There's been much iron-head vs. aluminum-head debate lately.
I have argued that the main attraction of the 3X00 engines is the roller cam adaptation of the blocks. I have argued that in our 6/60 motors that the heads are not the limitation of the engine's power.
We have GM documentation showing 100HP/L out of a 2.8 and a 3.0 respectively with 12.5:1 compression using Falconer ported heads and ITB-designed Falconer intake. Back then the 3.1 and 3.4 weren't around yet so who knows what they could have achieved.
Well, the "aluminum head enthusiasts" are trying to say that a race-prepped 3500 would destroy the old #'s of GM's smaller diplacement engines...due to the 'advances' of the heads...
So I looked for a race-prepped 3500 build.
I found this user on another forum named 'SuperDave'. http://www.jboi.org/registry/Superdave Seems pretty 'race-prepped' to me. Even uses a higher lift cam than what is possible on iron heads. Iron heads are limited to .510" lift. http://www.youtube.com/watch?v=vCdRKvMlmck 274.6 hp, 248.9 tq He was using higher compression but got poor results and when back down to stock 9.8:1 compression. He then decided to build a 1/4 mile car out of an '89 Camaro... You can see the build here: http://www.thirdgen.org/tec...633-my-3-5-swap.html He decided to at an ITM intake. Yep...INDIVIDUAL THROTTLE-BODY intake MANIFOLD. Funny thing is this car using a 700R transmission dynoed at lower HP but more TQ. 263/263 http://www.youtube.com/watch?v=DxewiTeUMlk
Is it possible that running open exhaust on his 3500Z car got him more HP and less TQ? Is it possible that running an exhaust on his 3500RS car got him more TQ and less HP?
I would answer yes to both questions.
Regardless he still didn't surpass GM's older tech. Yes, GM has to spin the motors higher with more comprssion, but that is easily made up for by the extra displacement and higher lift cam. IF the iron heads were restrictive, spinning the motors faster wouldn't have had any benefit.
The main point here is that iron heads can flow 300 HP naturally aspirated. They would have probably flowed even more behind a 3.4 or 3.5 L motor. Heck, Falconer's port-job on the intake side wasn't even as good as Oreif's porting when he dyno'ed 2 iron head engines at ~200rwhp.
HP is related to air flow. A 3.4 flows/requires as much air at 4941 RPM as a 2.8 does at 6000 RPM. Engines are just air pumps. Flow = flow. HP=HP. I have yet to see the heads being the factor in limiting horse power on v6/60 engines.
Originally posted by lou_dias: There's been much iron-head vs. aluminum-head debate lately.
Nope, just resistance from you Lou.
Had to take that shot at you. The best thing to do here I believe is for you to prove the opposition wrong by producing the results to support your position as the aluminum head believers are pretty confident about where they stand relative to iron heads. It's just a tough sell on the iron head's potential relative to the aluminum and considering the 3100 - 3500 all use the same cam spec if I read a link posted in your other thread correctly, it would stand to reason the two latter motors might do even better than OE spec with cams that match their increase in displacement.
Good luck trying though.
[This message has been edited by Joseph Upson (edited 02-18-2013).]
Just out of curiosity Lou, what is your take on why the 3x00 engines respond so much better to forced induction then iron head 60's do? I have seen a bunch of 3x00's with basically just a cam and a turbo putting out 400+ hp. I cant recall ever seeing an iron head do that. Do you have any examples of one? Is your engine running? Do you have a current dyno to post? I'm not saying your wrong, I just need more proof is all. So far your the only guy I've seen on the net arguing that the iron heads are just as good as the alum.
In Pat Ganahl's 1982 book "Buick, Ford, & Chevy 90/60 V-6 Performance", there are several examples of 60v6 engines producing in excess of 200HP using iron heads. Some quotes from the book are enlightening:
"One of the pioneering efforts in Chevrolet V-6 modification is a front-wheel-drive Citation put together in 1980 for the IMSA Champion Spark Plug Challenge road racing series. Campaigned by Don Yenko, owner of a Chevrolet dealership in Pennsylvania long known for building, racing, and selling specially prepared Chevies, this X-11 has proven very competitive in two years on the circuit. The 173-inch motor, assembled by Katech Engines (MT. Clemens, Michigan), has undergone only moderate modifications, yet delivers 230 horsepower with a single 2-barrel carb."
"Another excellent source for 60-degree V-6 parts is MacPherson Chevrolet. They have just completed a two-wheel-drive S-10 pickup for SCORE Class 7 off road competition, to be driven by Jerry McDonald. Using a H.O. 660 V-6 block sleeved down to 2.4 liters (146 cubic inches) and modified only with a reground cam, ported heads, custom pistons, headers, ignition, and a 2-barrel carb, the engine produces a healthy 220 horsepower and proved extremely quick and reliable in its first long distance race."
"Whether cylinder head wizards will be able to find any more hidden horsepower in these ports remains to be seen. However, initial work done by Diamond Racing, Katech Engines, and others seems to verify that Chevy did their job well. Extracting 250 to 300 horsepower from this V-6 requires virtually no port reworking other than the usual port matching and smoothing of casting irregularities. Using the stock intake manifold with a 2-barrel carb, the Katech-built Yenko motor produced 230 horsepower at 7200 rpm on the dyno. With alcohol injectors, Shelley Arkov projects 300 horsepower from his circle-track V-6 with virtually stock H.O. heads."
At the time that this book was written (1982), only stock components were available for these engines. Aluminum heads and the larger displacement 3.1 and 3.4 liter engines did not yet exist. Specifications for camshafts used in these racing engines were in some instances less radical than the Crane 272 used by many of the forum members in their rebuilds.
IP: Logged
11:52 AM
lou_dias Member
Posts: 5348 From: Warwick, RI Registered: Jun 2000
Had to take that shot at you. The best thing to do here I believe is for you to prove the opposition wrong by producing the results to support your position as the aluminum head believers are pretty confident about where they stand relative to iron heads. It's just a tough sell on the iron head's potential relative to the aluminum and considering the 3100 - 3500 all use the same cam spec if I read a link posted in your other thread correctly, it would stand to reason the two latter motors might do even better than OE spec with cams that match their increase in displacement.
Good luck trying though.
But in my own motor, I out-torqued most performance 3X00 builds using a stock 3400 cam and Fiero intake...and in most cased, out HP'd them also. I have repeatedly showed that it was the Fiero intake neck, A KNOWN RESTRICTION that is the only thing the limited my hp to 4400 rpm. It is the 'aluminum head enthusiasts' that are denial of this. I will be posting a dyno when I get my car back from the collision shop. I'm now using a Trueleo intake and L98 throttle body. Those youtube videos are not of me racing "stock" cars. The WRX I raced did a documented 13.2 1/4 mile and he couldn't pull on me even with the inside lane. The AWD turbo Eagle Summit did a documented 12.453 1/4 mile time. I know my hp is over 200, I just lack the dyno because I was too busy racing until the collision during one of the races gave me frame damage.
GM has documented 100HP/L on iron heads. So HEADS aren't the restriction. It doesn't matter that GEN3 can flow 25-33% more under un-natural circumstances if other parts of the motor are going to limit the VE. TPI has a naturally high VE.
@Bridgetown The motors in question are NA. Boost is a whole other ballgame.
[This message has been edited by lou_dias (edited 02-18-2013).]
But in my own motor, I out-torqued most performance 3X00 builds using a stock 3400 cam and Fiero intake...and in most cased, out HP'd them also. I have repeatedly showed that it was the Fiero intake neck, A KNOWN RESTRICTION that is the only think the limited my hp to 4400 rpm. It is the 'aluminum head enthusiasts' that are denial of this. I will be posting a dyno when I get my car back from the collision shop. I'm now using a Trueleo intake and L98 throttle body.
@Bridgetown The motors in question are NA. Boost is a whole other ballgame.
"Out torqued" is the same argument that people make when running TPI intakes on built-up GENII small blocks. http://forums.corvetteforum...thram-dyno-info.html When it is proven time and again, cars become faster when a better intake/head combination is used that has the power band within the gearing of the vehicles transmission. I think your next dyno will show a drop in torque and gain in power. I don’t think you will only gain top end and sacrifice nothing else. The design of the Fiero intake is more than just a "wall" at RPM the restriction will be a function are volume flow and Reynolds number, so it’s pretty well dependant on power production and manifold pressure. The runners have a smaller cross-section and long runner, favoring lower RPM airflow and induction pulse timing. The Trueleo has slightly shorter runners, greater plenum volume. Even if you still out torque a GENII 60V6, it may be no faster because of how gearing affects the engines RPM drop when all out accelerating. More average toque at the wheels for the longest time wins. Without a real head to head test, I don’t think we will solve this argument.
IP: Logged
12:49 PM
lou_dias Member
Posts: 5348 From: Warwick, RI Registered: Jun 2000
Just out of curiosity Lou, what is your take on why the 3x00 engines respond so much better to forced induction then iron head 60's do? I have seen a bunch of 3x00's with basically just a cam and a turbo putting out 400+ hp. I cant recall ever seeing an iron head do that. Do you have any examples of one? Is your engine running? Do you have a current dyno to post? I'm not saying your wrong, I just need more proof is all. So far your the only guy I've seen on the net arguing that the iron heads are just as good as the alum.
I'm saying they are just as good for all intents and purposed in naturally aspirated applications. I'm saying both iron and aluminum heads support HP potentials higher than we can spin the motors. I'm saying that even though aluminum head potential may be higher, without forced induction, you won't see it.
I don't have a current dyno sheet, just comparative track results against cars with documented 1/4 mile times...which you can see in my thread. I have repeatedly said "let's wait until I get my car back" so I can post a dyno, but aluminum head enthusiants keep trying to ram their version of the facts down my throat. Dyno's don't lie. If you read the build thread for SuperDave's Camaro, you'll see someone post about 2.8 S10's making 260hp but whomever was building them stopped since something wasn't selling. I forget the details. So it wasn't just GM getting big HP #'s from iron heads...
Originally posted by Heinz_57_Fiero: "Whether cylinder head wizards will be able to find any more hidden horsepower in these ports remains to be seen. However, initial work done by Diamond Racing, Katech Engines, and others seems to verify that Chevy did their job well. Extracting 250 to 300 horsepower from this V-6 requires virtually no port reworking other than the usual port matching and smoothing of casting irregularities. Using the stock intake manifold with a 2-barrel carb, the Katech-built Yenko motor produced 230 horsepower at 7200 rpm on the dyno. With alcohol injectors, Shelley Arkov projects 300 horsepower from his circle-track V-6 with virtually stock H.O. heads.".
quote
Gasoline - Gasoline is what most of our cars came setup so it's usually what we stick with. Gasoline is a mixture of hydrocarbons. The petroleum distillate fraction termed "gasoline" contains mostly saturated hydrocarbons usually with a chemical formula of C8H18. The air fuel ratio, A/F Ratio, for complete combustion is 14.7:1, stoichiometric. The A/F ratio for maximum power is approximately 12.5:1 - 12.8:1. This means that our engine at max power, 12.8:1, consumes 12.8 pounds of air for 1 pound of fuel. Gasoline has approximately 18,400 BTU/lb . Using the air flow calculator with the default inputs we get our 355 SBC consumes 567.53 cfm @ 6500rpm which is 42.64 pounds of air and consumes 2.89 pounds of fuel. Therefore if we are using gasoline our engine is producing 53,176 BTU's of energy at 6500 rpm.
Alcohol (Methanol) - Alcohol is usually used in the form of Methyl alcohol or methanol. CH3OH is the chemical formula. Methanol burns at a much richer mixture than gasoline does, between 5.0:1 - 6.0:1. That's 5 lbs of air to one pound of fuel. Methanol has approximately 9,500 BTU/lb. Using our 355, example above, SBC consumes 567.53 cfm @ 6500rpm which is 42.64 pounds of air and now at 6.0:1 ratio for Methanol is 7.11 pounds of fuel. Therefore if we are using Methanol fuel our engine is producing 67,545 BTU's of energy at 6500 rpm.
Gasoline produces roughly 78% less power than alchohol mixtures, due to oxygen content. An esitmated 300hp become 234 when using gasoline. And that was an estimated power level, still not proven.
[This message has been edited by FieroWannaBe (edited 02-18-2013).]
IP: Logged
12:58 PM
lou_dias Member
Posts: 5348 From: Warwick, RI Registered: Jun 2000
"Out torqued" is the same argument that people make when running TPI intakes on built-up GENII small blocks. http://forums.corvetteforum...thram-dyno-info.html When it is proven time and again, cars become faster when a better intake/head combination is used that has the power band within the gearing of the vehicles transmission. I think your next dyno will show a drop in torque and gain in power. I don’t think you will only gain top end and sacrifice nothing else. The design of the Fiero intake is more than just a "wall" at RPM the restriction will be a function are volume flow and Reynolds number, so it’s pretty well dependant on power production and manifold pressure. The runners have a smaller cross-section and long runner, favoring lower RPM airflow and induction pulse timing. The Trueleo has slightly shorter runners, greater plenum volume. Even if you still out torque a GENII 60V6, it may be no faster because of how gearing affects the engines RPM drop when all out accelerating. More average toque at the wheels for the longest time wins. Without a real head to head test, I don’t think we will solve this argument.
The TPI intake was designed for a 305. Just like the Fiero intake was designed to a 2.8. I modified as much as I cold except the neck to make my 3.4 happy but a choke point is a choke point. So I switched to the Trueleo. Results to be determined at a later date.
IP: Logged
01:06 PM
lou_dias Member
Posts: 5348 From: Warwick, RI Registered: Jun 2000
Originally posted by FieroWannaBe: Gasoline produces roughly 78% less power than alchohol mixtures, due to oxygen content. An esitmated 300hp become 234 when using gasoline. And that was an estimated power level, still not proven.
You have a good point about the fuel, however, as Superdave is a 1/4 guy, he may have been running track fuel. We simply don't know.
Octane level of gasoline has little affect on energy content. It is still gasoline, but the acatual composition of fossil fuels are not so easily predicted. Octane is a rating of resistance to burning. Higher octane is harder to ignite, allowing for more timing advance and resistance the negative work during the compression cycle. The combustion cycle on an engine can extend far beyond the 180 degress it takes for the piston to make its stroke downward. Any pressure in the cylinder prior to TDC makes for negative work on the crankshaft, do to the net work to compress gasses. If race gasoline is still gasoline only, the energy available is directly related to the energy produced for each reduction process in the oxidation of the fuels. The more oxygen burned the more energy released. C8H18 mixtures, regardless of octane rating, should produce the same levels of reactants and therefor energy. These processes are highly complex and difficult to predict. But any power increase from using high octane race fuel will be due to timing and static compression, not from energy content. Alcohol mixtures not only contain there own oxygen in the fuel, allowing for richer AFRs and therefor more energy release per amount of air ingested, its lower vapor pressure means it can resist compression knock easier by extracting heat due to vaporization.
Long story short: race gas in street motors makes a lot less power than alcohol is street motors because the fuel benifits of race gas are hard to extract, since stock motors cannot be easily allowed to run higher static compression. Using Alcohol at the proper power rich AFR can produce great power results for little or no changes to the longblock.
EDIT: I was wrong earlier.
[This message has been edited by FieroWannaBe (edited 02-18-2013).]
[quote]We have GM documentation showing 100HP/L out of a 2.8 and a 3.0 respectively with 12.5:1 compression using Falconer ported heads and ITB-designed Falconer intake. Back then the 3.1 and 3.4 weren't around yet so who knows what they could have achieved.
so you would consider this engine "race-prepped" OK. 12.5:1 compression is not very streetable. I wonder what the cam profile looked like...
really? you consider a stock bottom end to be "race prepped??"
quote
He was using higher compression but got poor results and when back down to stock 9.8:1 compression.
again, really? i had no idea that you followed that build thread so closely. can you provide truth data for this claim? those who actually followed the ENTIRE build thread know the answer, lets see how much you followed....
1/4 mile car only? or is it streetable too? since you may have followed this build too, is the ITB set up still on there? Is it possible that running open exhaust on his 3500Z car got him more HP and less TQ? Is it possible that running an exhaust on his 3500RS car got him more TQ and less HP?
I would answer yes to both questions.
Regardless he still didn't surpass GM's older tech. Yes, GM has to spin the motors higher with more comprssion, but that is easily made up for by the extra displacement and higher lift cam. IF the iron heads were restrictive, spinning the motors faster wouldn't have had any benefit.
quote
The main point here is that iron heads can flow 300 HP naturally aspirated. They would have probably flowed even more behind a 3.4 or 3.5 L motor. Heck, Falconer's port-job on the intake side wasn't even as good as Oreif's porting when he dyno'ed 2 iron head engines at ~200rwhp.
the ACTUAL main point here is that GEN III heads are far better to start with, where as irons need ALOT of help just to be within reach of untouched GENIII heads. canted valves, higher ports, LARGER ports, better quench areas all contribute to why most people start with alums. most of us have built engines using the iron head top end, and found the limits fairly quick. I challenge you to build your iron head engine, dyno it, race it, then do the same thing with an LX9. spend the same amount of time and perform the same modifications and, pound for pound, Im sure you will like the results. no disrespect, just try it... .[/QUOTE]
[This message has been edited by sleevePAPA (edited 02-18-2013).]
IP: Logged
03:31 PM
joshua riedl Member
Posts: 1426 From: watertown wi USA Registered: Jan 2004
Perhaps if you read his thread your questions would be answered.
Stock bottom end is better on newer blocks than older blocks. That's not what we're comparing is it?
Being a Fiero owner, I can improve iron heads cheaper than I can buy GEN3 heads...isn't that the point rather than telling every iron head motor owner that their heads are fail and that they are stupid for starting with anything less than a full 3X00 swap?
PS, if you actually bothered to read his motor build, you'd read the words "race prepped" a few times.
IP: Logged
05:01 PM
lou_dias Member
Posts: 5348 From: Warwick, RI Registered: Jun 2000
So you made more power with the trueleo? Because I could have sworn the last time I asked you said it lowered power. I'll have to find the links because there is more than one. I suppose it's easier to hide the truth by starting new threads.
IP: Logged
05:13 PM
joshua riedl Member
Posts: 1426 From: watertown wi USA Registered: Jan 2004
Perhaps if you read his thread your questions would be answered.
[quote]Stock bottom end is better on newer blocks than older blocks. That's not what we're comparing is it?
Im well aware of the priority main feed oiling system, hydraulic roller cam, cross-bolted main caps, etc. you dont have to tell me which shortblock is better. no kidding thats not what we are comparing. if thats the way its going to be then youre mention of the 12.5:1 compression RACE engine doesnt belong. and even then comparing that to a bonestock LX9 shortblock is APPLES TO ORANGES. I dont know why you keep trying to make that comparision.
quote
Being a Fiero owner, I can improve iron heads cheaper than I can buy GEN3 heads...isn't that the point rather than telling every iron head motor owner that their heads are fail and that they are stupid for starting with anything less than a full 3X00 swap?
car-part.com, you can find a WHOLE engine for less than 500 bucks with fairly low miles. sure you can modify and improve the heads and save a buck or two, still wont touch GENIII heads. maybe someday you will experiement more with them and find the benefit?
quote
PS, if you actually bothered to read his motor build, you'd read the words "race prepped" a few times.
[/QUOTE]
only items on that engine that were considered "race prepped" would be the porting of the heads and maybe the intake. some other modifications were adding springs seats to keep the springs from dancing around in the pocket, better beehives, modified lifters, etc. i read that build thread from the start BTW. I think your opinion would be taken more seriously if you actually built the GENIII, or have you? so far you are the only real proponent of the GEN I topend and though you have some impressive numbers, they really dont prove much. I guess its more a matter of preference. again, I mean no disrespect. If the GEN I heads are your calling, by all means dont let me get in the way of that. cheers
[This message has been edited by sleevePAPA (edited 02-18-2013).]
IP: Logged
06:02 PM
lateFormula Member
Posts: 1048 From: Detroit Rock City Registered: Jul 2002
Originally posted by FieroWannaBe: Higher octane is harder to ignite, allowing for less timing advance
Actually higher octane will allow you to use more advance on the ignition timing. With lower octane you may need to retard the timing to prevent knock.
IP: Logged
06:54 PM
Blacktree Member
Posts: 20770 From: Central Florida Registered: Dec 2001
The only reason I'm keeping the iron heads on my 3.4 V6 is because my Falconer intake won't fit the aluminum heads. But I'm willing to take a small performance hit, to keep that sexy Falconer intake.
Stock for stock, the Gen III engines outperform their Gen I counterparts. And it isn't solely due to the camshaft. It's the "complete package", so to speak. To point out one single part and say "all the performance increase is due to THIS" seems kinda silly to me.
IP: Logged
07:14 PM
82-T/A [At Work] Member
Posts: 24139 From: Florida USA Registered: Aug 2002
I just want to make some comments about everyone here.
I really hate to see people get "negative" in a discussion about things that are this technical in nature. Obviously, everyone who's involved in the discussion here is fairly experienced with technically... I would hate to see anyone actually get "upset" with anyone else here and leave because of a technical disagreement.
So I'd just like to emplore everyone to be cool with eachother even if you guys have a disagreement.
For the record, I'm going to go with a roller block and iron heads because it'll allow me to keep my factory intake, which is important to me because I want to keep my car stock looking while still seeing the benefit of improved quality of performance. I'm going to have a stick anyway, so I should still be able to use the improved low-end power.
IP: Logged
07:29 PM
PFF
System Bot
ericjon262 Member
Posts: 3109 From: everywhere. Registered: Jan 2010
In Pat Ganahl's 1982 book "Buick, Ford, & Chevy 90/60 V-6 Performance", there are several examples of 60v6 engines producing in excess of 200HP using iron heads. Some quotes from the book are enlightening:
"One of the pioneering efforts in Chevrolet V-6 modification is a front-wheel-drive Citation put together in 1980 for the IMSA Champion Spark Plug Challenge road racing series. Campaigned by Don Yenko, owner of a Chevrolet dealership in Pennsylvania long known for building, racing, and selling specially prepared Chevies, this X-11 has proven very competitive in two years on the circuit. The 173-inch motor, assembled by Katech Engines (MT. Clemens, Michigan), has undergone only moderate modifications, yet delivers 230 horsepower with a single 2-barrel carb."
"Another excellent source for 60-degree V-6 parts is MacPherson Chevrolet. They have just completed a two-wheel-drive S-10 pickup for SCORE Class 7 off road competition, to be driven by Jerry McDonald. Using a H.O. 660 V-6 block sleeved down to 2.4 liters (146 cubic inches) and modified only with a reground cam, ported heads, custom pistons, headers, ignition, and a 2-barrel carb, the engine produces a healthy 220 horsepower and proved extremely quick and reliable in its first long distance race."
"Whether cylinder head wizards will be able to find any more hidden horsepower in these ports remains to be seen. However, initial work done by Diamond Racing, Katech Engines, and others seems to verify that Chevy did their job well. Extracting 250 to 300 horsepower from this V-6 requires virtually no port reworking other than the usual port matching and smoothing of casting irregularities. Using the stock intake manifold with a 2-barrel carb, the Katech-built Yenko motor produced 230 horsepower at 7200 rpm on the dyno. With alcohol injectors, Shelley Arkov projects 300 horsepower from his circle-track V-6 with virtually stock H.O. heads."
At the time that this book was written (1982), only stock components were available for these engines. Aluminum heads and the larger displacement 3.1 and 3.4 liter engines did not yet exist. Specifications for camshafts used in these racing engines were in some instances less radical than the Crane 272 used by many of the forum members in their rebuilds.
HP at the crank or at the wheels?(if wheels, auto or manual? transverse or longitudinal?) gross or net HP? what accessories run off the motor?
To many unknowns with this post to be valid in the argument.
Actually higher octane will allow you to use more advance on the ignition timing. With lower octane you may need to retard the timing to prevent knock.
You’re absolutely correct; pretty much everything I wrote was kind of wrong looking at it 8 hours later. The benefit of using the higher octane allows greater advance. Running the optimal advance allows the peak cylinder pressure to correlate with the crank position that creates the most torque. The octane prevents pre ignition BECAUSE of the negative work scenario creating an auto ignition atmosphere from excess in-cylinder pressure as expanding combustion gasses and a shrinking quench area rais the combustion pressure and temperature. The mixture needs to have resistance to burning to survive longer before the flame front can ignite the mixture.
There's been much iron-head vs. aluminum-head debate lately.
I have argued that the main attraction of the 3X00 engines is the roller cam adaptation of the blocks. I have argued that in our 6/60 motors that the heads are not the limitation of the engine's power.
We have GM documentation showing 100HP/L out of a 2.8 and a 3.0 respectively with 12.5:1 compression using Falconer ported heads and ITB-designed Falconer intake. Back then the 3.1 and 3.4 weren't around yet so who knows what they could have achieved.
Well, the "aluminum head enthusiasts" are trying to say that a race-prepped 3500 would destroy the old #'s of GM's smaller diplacement engines...due to the 'advances' of the heads...
So I looked for a race-prepped 3500 build.
I found this user on another forum named 'SuperDave'. http://www.jboi.org/registry/Superdave Seems pretty 'race-prepped' to me. Even uses a higher lift cam than what is possible on iron heads. Iron heads are limited to .510" lift. http://www.youtube.com/watch?v=vCdRKvMlmck 274.6 hp, 248.9 tq He was using higher compression but got poor results and when back down to stock 9.8:1 compression. He then decided to build a 1/4 mile car out of an '89 Camaro... You can see the build here: http://www.thirdgen.org/tec...633-my-3-5-swap.html He decided to at an ITM intake. Yep...INDIVIDUAL THROTTLE-BODY intake MANIFOLD. Funny thing is this car using a 700R transmission dynoed at lower HP but more TQ. 263/263 http://www.youtube.com/watch?v=DxewiTeUMlk
Is it possible that running open exhaust on his 3500Z car got him more HP and less TQ? Is it possible that running an exhaust on his 3500RS car got him more TQ and less HP?
I would answer yes to both questions.
Regardless he still didn't surpass GM's older tech. Yes, GM has to spin the motors higher with more comprssion, but that is easily made up for by the extra displacement and higher lift cam. IF the iron heads were restrictive, spinning the motors faster wouldn't have had any benefit.
The main point here is that iron heads can flow 300 HP naturally aspirated. They would have probably flowed even more behind a 3.4 or 3.5 L motor. Heck, Falconer's port-job on the intake side wasn't even as good as Oreif's porting when he dyno'ed 2 iron head engines at ~200rwhp.
HP is related to air flow. A 3.4 flows/requires as much air at 4941 RPM as a 2.8 does at 6000 RPM. Engines are just air pumps. Flow = flow. HP=HP. I have yet to see the heads being the factor in limiting horse power on v6/60 engines.
Superdave's cars were not "race prepped" I'm not sure where you keep getting that... his motor is a HCI 3500. that hardly means "race prepped" if his motor is race prepped, all the LSX motors running a .600" lift on the street must all be Pro mods...
I'd like to see you run half the cam Superdave runs, and not give up all of your low end, head flow matters, and it matters alot in the world of performance.
I'll make the comparison again. this is like saying you can put 305 TBI truck heads on a aluminum head 350 LT1 and make the same power (or more) because it has a roller cam... it's not going to happen... ever.
Answer, if this was the case, how come the L03 in a truck with a flat tappet cam, and the L03 in a Camaro or firebird with a roller cam both made the same power and torque?
If there were an appreciable difference in power, GM would have given both engines a separate designation, it's easier to sell a base model Camaro with 200HP Vs 170HP....
you have claimed 300 HP numerous times, you have yet to back it up with a dynograph, you have also not told us whether that was net power, gross power. crank power, at the tires, ect... you have nothing to back up your claims.
I've said it before and I will say it again, post a dynograph showing a FLAT torque curve from 2000-6000 RPMs, and I will shut up.
------------------ we're in desperate need of a little more religion to nurse your god-like point of view...
Originally posted by Blacktree: The only reason I'm keeping the iron heads on my 3.4 V6 is because my Falconer intake won't fit the aluminum heads. But I'm willing to take a small performance hit, to keep that sexy Falconer intake.
Stock for stock, the Gen III engines outperform their Gen I counterparts. And it isn't solely due to the camshaft. It's the "complete package", so to speak. To point out one single part and say "all the performance increase is due to THIS" seems kinda silly to me.
Yes, but ignoring each part's individual contribution is no better, especially when they are not equal and you are dealing with a hybrid such as in your case. Camshafts are pretty straightforward and each has its pros and cons on the way to making power, solid vs. hydraulic vs. roller. Cylinder heads on the other hand are either okay, better, or best. There is no con to an organized flow increase through better design. The subject is about cylinder head flow improvement over the generations and whether or not iron heads can attain aluminum head performance despite their stock history of under performing aluminum heads. The 3.4 has a pretty good flowing intake in the F-body but still rates less than the 3400 and I'd say the 3.4L has a better flowing exhaust compared to the wrap around in front wheel drives.
Not much has been said about it but in addition to the flow improvement, there is substantial spark knock resistance in the combustion chamber design of aluminum heads that keeps high performance builds with them practical. I highly doubt the iron heads can sustain the kind of compression ratios run with aluminum heads on pump gas. Look at the difference in the spark tables for the two. Practicality should be considered as alcohol/race gas is not sold at the local gas station. I ran at least 11.5:1 compression with boost in the 3.9L on pump 93, and drove the car in the Summer a few times on 89, with no intercooler and 135 deg cruise inlet temps, off boost on long trips without a problem on the same compression and now routinely hit 10-13 psi with 11:1 compression still on 93 with no spark knock problems at that boost level and discovered along the way that I don't need the water injection (which comes on very late and in a small quantity) to do it. I keep it in place for added safety and I'm still scared.
Discussion/debate is good and although a little heated here in some places, for the most part it's tact which makes it okay. As I stated earlier, the best thing to do here to put the matter to rest is to prove it. I still wouldn't go back to iron heads if Lou succeeds, but I'd like to see him achieve better results and get on a track that goes in a straight line for a change.
IP: Logged
09:03 PM
ericjon262 Member
Posts: 3109 From: everywhere. Registered: Jan 2010
Yes, but ignoring each part's individual contribution is no better, especially when they are not equal and you are dealing with a hybrid such as in your case. Camshafts are pretty straightforward and each has its pros and cons on the way to making power, solid vs. hydraulic vs. roller. Cylinder heads on the other hand are either okay, better, or best. There is no con to an organized flow increase through better design. The subject is about cylinder head flow improvement over the generations and whether or not iron heads can attain aluminum head performance despite their stock history of under performing aluminum heads. The 3.4 has a pretty good flowing intake in the F-body but still rates less than the 3400 and I'd say the 3.4L has a better flowing exhaust compared to the wrap around in front wheel drives. Not much has been said about it but in addition to the flow improvement, there is substantial spark knock resistance in the combustion chamber design of aluminum heads that keeps high performance builds with them practical. I highly doubt the iron heads can sustain the kind of compression ratios run with aluminum heads on pump gas. Look at the difference in the spark tables for the two. Practicality should be considered as alcohol/race gas is not sold at the local gas station. I ran at least 11.5:1 compression with boost in the 3.9L on pump 93, and drove the car in the Summer a few times on 89, with no intercooler and 135 deg cruise inlet temps, off boost on long trips without a problem on the same compression and now routinely hit 10-13 psi with 11:1 compression still on 93 with no spark knock problems at that boost level and discovered along the way that I don't need the water injection (which comes on very late and in a small quantity) to do it. I keep it in place for added safety and I'm still scared.
Discussion/debate is good and although a little heated here in some places, for the most part it's tact which makes it okay. As I stated earlier, the best thing to do here to put the matter to rest is to prove it. I still wouldn't go back to iron heads if Lou succeeds, but I'd like to see him achieve better results and get on a track that goes in a straight line for a change.
and that has alot more to do with quench and chamber design than it does with material.
------------------ we're in desperate need of a little more religion to nurse your god-like point of view...
Originally posted by ericjon262: and that has alot more to do with quench and chamber design than it does with material.
I said that.
quote
Originally posted by Joseph Upson: Not much has been said about it but in addition to the flow improvement, there is substantial spark knock resistance in the combustion chamber design of aluminum heads that keeps high performance builds with them practical.
Go finish your motor.
IP: Logged
10:05 PM
ericjon262 Member
Posts: 3109 From: everywhere. Registered: Jan 2010
Perhaps if you read his thread your questions would be answered.
Stock bottom end is better on newer blocks than older blocks. That's not what we're comparing is it?
Being a Fiero owner, I can improve iron heads cheaper than I can buy GEN3 heads...isn't that the point rather than telling every iron head motor owner that their heads are fail and that they are stupid for starting with anything less than a full 3X00 swap?
PS, if you actually bothered to read his motor build, you'd read the words "race prepped" a few times.
I think the problem is that you would rather put iron heads on an aluminum head block. Putting aluminum heads on an iron head block doesn't make too much sense either; I wouldn't even recommend it unless it was a race build. My problem is that people seem to think its best to put iron heads on an ALUMINUM HEAD MOTOR even though the mods required to swap the whole motor are minor at best. If it was a first time build for me I wouldn't attempt swapping on iron heads when the whole motor practically bolts in (speaking from experience).
Originally posted by bcampbell: I think the problem is that you would rather put iron heads on an aluminum head block. Putting aluminum heads on an iron head block doesn't make too much sense either; I wouldn't even recommend it unless it was a race build. My problem is that people seem to think its best to put iron heads on an ALUMINUM HEAD MOTOR even though the mods required to swap the whole motor are minor at best. If it was a first time build for me I wouldn't attempt swapping on iron heads when the whole motor practically bolts in (speaking from experience).
Actually putting aluminum heads on an iron head motor makes a lot of sense considering as is they flow better than the iron heads, the block will not know the difference and thicker gaskets are available to bring compression down to a practical range, or for a race engine you can use stock gaskets and race gas for an exceptional boost in performance. Sixshooter on the V6Z24 forum did something like this to his S10 I recall some years back as far as the head swap is concerned.
Actually putting aluminum heads on an iron head motor makes a lot of sense considering as is they flow better than the iron heads, the block will not know the difference and thicker gaskets are available to bring compression down to a practical range, or for a race engine you can use stock gaskets and race gas for an exceptional boost in performance. Sixshooter on the V6Z24 forum did something like this to his S10 I recall some years back as far as the head swap is concerned.
the majority of Fiero owners cant afford race gas, or even know how to get it. And there is an unnecessary fear of wiring changes and computer work, when in reality the cost of head gaskets and pistons can exceeds those. The truth is people really like the look of the red powdercoat and brushed aluminum fins. 3x00 motors dont come that way fiero did though. The stock look, is thrown away when people put on trueleo intaks and swap in a DIS brick. But they get to keep the sweet aluminum valve covers with brushed fins and red paint. And looks are the most imp[ortant thing to many people. The fiero is very underperforming, but looks otherwise. (get the trend)
Originally posted by FieroWannaBe: the majority of Fiero owners cant afford race gas, or even know how to get it. And there is an unnecessary fear of wiring changes and computer work, when in reality the cost of head gaskets and pistons can exceeds those. The truth is people really like the look of the red powdercoat and brushed aluminum fins. 3x00 motors dont come that way fiero did though. The stock look, is thrown away when people put on trueleo intaks and swap in a DIS brick. But they get to keep the sweet aluminum valve covers with brushed fins and red paint. And looks are the most imp[ortant thing to many people. The fiero is very underperforming, but looks otherwise. (get the trend)
That goes back to the topic of the later heads being all the better, as a race application has been mentioned and the aluminum head design takes a little longer to require alternative fuels as performance level increases. Gasket and piston options are available for the typical costs of increasing performance and many here spend the associated amounts on a regular basis.
The Fiero intake and valve cover design is rather unique and nice in appearance but unless you drive around with your decklid off or open, no one gets to appreciate them and they certainly don't improve performance. If I start missing the red dress of the Fiero valve covers and intake I'll put a picture of them on the dash and keep the 3x00 in place.
IP: Logged
08:41 AM
Will Member
Posts: 14250 From: Where you least expect me Registered: Jun 2000
There's been much iron-head vs. aluminum-head debate lately.
We have GM documentation showing 100HP/L out of a 2.8 and a 3.0 respectively with 12.5:1 compression using Falconer ported heads and ITB-designed Falconer intake. Back then the 3.1 and 3.4 weren't around yet so who knows what they could have achieved.
HP is related to air flow. A 3.4 flows/requires as much air at 4941 RPM as a 2.8 does at 6000 RPM. Engines are just air pumps. Flow = flow. HP=HP. I have yet to see the heads being the factor in limiting horse power on v6/60 engines.
You just proved the aluminum head argument...
The iron head race engine numbers were at the CRANK. You posted an engine in a MUCH lower state of tune making essentially that output at the WHEELS.
You say that HP is related to airflow, and then you say that the heads that flow better won't make any more power.
