Well, I got my car dynoed saturday.
I've had a re-manned 3.4 put in from the Fiero Factory with ported heads, intake, hollow cat, IRM dual exhaust, K&N, ADS superchip, accel coil, SpiralMax, 1.52 Roller Rockers, Crane Compucam .423/.423

The graph can be seen at http://www.geocities.com/lou_dias/dyno.jpg

My peak HP was 146.3 at the wheels and peak torque was 201.6... What do you guys see as the gross HP?

HP was dissapointing but the torque was impressive.
By comparison, my little brother's stock 98 TA produced 301hp on the same day.

I want to do this again but this time try removing the spiral max and try putting in the stock chip. The place we went to rushed us out of there and didn't bother asking if we wanted any tuning with timing or anything else.

Those are good numbers! You can't compare a 3.4 V-6 to a 5.7 V-8....apples and oranges.

Given a "normal" 20% driveline loss (may be less), that would give you about 175 HP and 240 pounds of torque. Not bad at all.....certainly more than a stock 2.8.

I think it would have been more interesting to dyno the stock 2.8 before transplanting a 3.4....that would let you know the horsepower your particular car has gained.

Those are some good numbers. I am especially impressed with the torque numbers. With my 2.8 and a 50 shot of nitrous I put a little over 200 torque to the wheels peak as well. So your 3.4 is making almost as much torque as most 2.8's would with a 50 shot of nitrous. I think that is very impressive.

However I don't think it is making as much as 240 tq at the crank however. When I had mine dynoed it put down 155 peak tq corrected. That was with no mods either and 110 hp. Hp was right on with about a 15% driveline loss but the torque is not at 15% if it was rated at 165 lb ft from the factory. It seems to me that peak torque is not affected as much at the driveline as hp is because the wheels are spinning less at a lower rpm so there isn't as much friction at the wheels or throughout the drivetrain. I could be wrong however so if I am then just say so.

I would definately take that spiralmax thing out. It isn't doing any good.

Also while looking at the chart it looks like the chart is incorrect. Hp is a factor of torque and always crosses each otehr at 5252 rpm but on your dyno printout they cross at around 4000 rpm and not at the 5252. It seems to me that it is incorrect and if it is and you slide the graph to the left so they cross at 5252 then I think you will have a higher hp reading. Right guys??

Glad to see that a 3.4 has been tested to see what numbers it can really lay down. It seems to me that it falls in the range of 170 hp and around 210 or so torque with the swap so 30 hp and 50 torque ain't that bad. pretty good I think for a simple bolt in engine swap.

------------------
Shaun-Toledo OH, 85 GT
3.2 With nitrous
http://members.aol.com/shaun41178

I hope to do it again in a month. 3 more runs. I want to remove the spiralmax, then put back the factory chip and then maybe play with the timing.

For the record, I was at 3300 miles since my last oil change and I wasn't getting air blown into the inlet. Also, I was running 89 octane.

you numbers aren't far off from BBBADs 350.

and right along with a nitrous 2.8 car!

did you do the install? Have you had a chance to run it on a strip?

The Fiero Factory did the install.
Remeber, this is at the wheels. I don't necessarily believe in quater miles times as a means of performance measuring. I know Mustangs that'll beat me in the quarter mile but have a low top speed due to a 4.11 axle gear and I've had my car up to 148mph before.
IE, I'd loose the sprint but with the marathon.

Not bad! Glade to see someone finally got a dyno done on a 3.4 fiero. Shaun is right; the HP and torque curve should always cross a 5,252-RPM regardless if its net, gross, corrected, flywheel, and drive wheel ratings. I don't know why yours does not. You should call the dyno shop and ask them why. The formula for HP is HP=torque*RPM/5,252.

If you do the math, the ratio between 4000 and 5252 is similar to 6 and 8. Not exact, but close.
I don't know how the dyno knows what the RPM is, but I'm making a wild-ass guess that it thinks it's looking at a V-8, instead of a 6.
What were they running just before you showed up?
In any event, it looks really good. Makes tons of torque for a looonnnnnnng time.
I'll bet it will plant you against the backrest.

------------------
Raydar
88 Formula T-Top
88 Coupe (ISO big V-6)

Out of my mind.
Back in five minutes.

So contrary to popular belief, if I install a 3.4, I will not get approx 200hp and 210ft/lb? Damnit.. This was my big plan..

is your car an automatic i was looking at the spike at 2200rpm.. there is a "force scaling" option in the winPEP program that the dyno runs off of. if that isn't clicked on then you may have the curves intersect at an arbitrary number. how do you like the IRM exhaust?

No you won't get 200hp unless you use the aluminum Gen ][ heads and a roller cam. Basically, you want to soup up the minvan engine. I've stated this many times. SFI and aluminum heads are the way to go with the 3.4. even all of today's V8's have aluminum heads...roller cams and higher compression and with SFI, you get better air fuel control. you'll get 20 horses more out of the aluminum head minivan 3.4 than the cast iron 3.4 camaro engine. Associated Auto sells a minivan kit for like $500...

Don't get me wrong, the torque is great. But I'm souped up to the max and my little brother's STOCK LS1 made OVER DOUBLE (301hp)my HP with only 70% more cubic inches. His friend's stock RAM AIR made 324 hp on the dyno. Torque numbers matched up fairly even when comparing cubic inches to ft-lbs of torque on both engines.

Hey I can answer why the curves don't cross at 5250. If you will notice the torque and HP numbers are not the same scale. On the left side(HP) the scale is -25 to 175 on the right(FT-LB) it's -25 to 225. Who says old fogies don't know nuttin? T and HP seem to be about 128 at 5252

Wow, great info. That's a pretty good jump from stock. Did you clean out the restrictions in your stock exhaust manifolds before you put the motor back in or are you running any kind of headers? Maybe that would help keep the horsepower climbing over 4500 rpm.

See ya,
Dave

Actually, I have Sprint Headers from the fiero store, and a hollow cat. Looks like I need a hotter cam to really open it up.
This engine performs as advertised by the cam specs. I wanted a hotter cam but I settled for the 423/423 Crane compucam because I intend to turbo it next year.

200 HP is entirely possible with the iron heads. Iron heads believe it or not make more HP than aluminum heads. Iron heads are more thermally efficient than aluminum heads are. The aluminum heads on the 3.1 engine may make more HP because they have splayed valves and optimal intake runners that flow more air than the iron heads do. The only advantage aluminum has over iron is weight savings and that’s it. You can make the iron heads better than the aluminum heads by having them properly ported and having a three angle valve job done on them by someone who knows what they are doing. With the GM 3.4 crate engine performance cam, ported heads, real tuned headers (not sprint manifolds), a higher compression ratio, blueprinted block, and a custom prom chip you can make over 200 HP with the iron head 3.4 and still pass the sniffer test.

I put in the specs for the crane 2030 performance cam with ported heads, high performance manifolds, and 9.0 compression on my dyno program and got 177 HP @ 5000 RPM and 217 ft. lbs. of torque @ 3500 RPM. That is pretty close to what you have on your real dyno taken account for the driveline loss. With the combination I stated above and a 9.7 to 1 compression ratio I got 209 HP @ 5000 RPM and 236 ft. lbs. of torque @ 3500 RPM.

So what you are saying that Lou's machinist does not know how to port heads? :-)
I think its funny how people will argue a point even when the real data is right in front of them. I would sure like to find a machinist who can get a 31.7% exhaust flow increase on an iron head. Maybe he could bore it into a D shape or something, since thats what the Gen III aluminum heads have to use to get that kind of flow increase.

I always thought that since you could get away with more compression with aluminum heads that you could squeeze more power out of them. Do I stand corrected?

88formula,

I don't want to start a pissing match or a flame war but I'll have to dissagree with your statements: "Iron heads are more thermally efficient than aluminum heads are" and "The only advantage aluminum has over iron is weight savings and that’s it".

First, aluminum is MUCH more thermally efficient than any ferrous metal. Since the aluminum conducts heat better that iron, it allows the motor to operate at a higher compression level, using the same type fuel, without premature detonation.

Second, because the motor can operate at a higher compression level, by nature, it will make more power. As you stated; "...9.0 compression on my dyno program and got 177 HP @ 5000 RPM and 217 ft. lbs. of torque @ 3500 RPM... 9.7 to 1 compression ratio I got 209 HP @ 5000 RPM and 236 ft. lbs. of torque @ 3500 RPM".

The weight savings are an added bonus.

Roy

Right Roy, so my limiting factors are:
Compression ratio and cam specs
Again, it's probably best that my compression ration and cam specs are what they are so that I can still turbo this baby next year. If it blows up on me before then, I will either sell it and get a 97 Vette or put in an Montana 3.4

Sarloc, I am not saying that Lou’s machinist does not know how to port heads. I don’t know who Lou’s machinist is and I don’t care. I also don’t see any factual information here that directly says those heads flow 31.7% more air than the iron heads. To get that kind of information Sarloc you would have to take a set of the iron heads and the generation three aluminum heads and have them flow-bench tested on the same flow bench. You can’t compare head flow numbers from two different flow benches because they will never be the same.

Terrybogin and Mrfixit58, to get the same thermal efficiency of an iron head with a 9 to 1 compression ratio from an aluminum head you would need approximately a 10 to 1 compression ratio. This is because the heads on an engine are like a big heat sink that draws energy from the combustion event. Cast iron is not a good heat sink and does not transfer heat as well as aluminum does to the coolant and away from the combustion chamber. The iron heads have reduced thermal transfer into the coolant passages and surrounding material leaving more energy available to push against the piston, which will then create more force to turn the crankshaft. The reason why you can run a higher compression ratio with aluminum heads is because of aluminum’s higher thermal transfer; more heat energy goes out the head so that the fuel does not reach its flash point as easily thwarting off Pre–ignition and detonation. The increased transfer of heat from the combustion event into the coolant makes your cooling system work harder also. It is the expansion of heat that actually pushes the piston down its bore and the more of that heat energy that goes out the head through the coolant the less heat there is to push the piston down. Most engines loose something like 1/3 the of the heat energy through the cooling system and 1/3 out the exhaust system with 1/3 left to push the piston down.

Haven’t any of you guys ever heard of some racers using thermal barrier coatings on the tops of pistons and in the combustion chambers? These thermal barrier coatings are designed to reduce thermal transfer from the combustion event into the heads and pistons. By putting the heat back into the combustion process, the engine produces more power and is less prone to detonation. The heat is also reflected, and that increases flame travel speed and allows cylinder pressure to peak higher and sooner in the crankshaft’s arc of rotation. Accordingly, the increased burn rate requires less tatal timing to produce maximum brake torque. The coatings used on pistons and combustion chambers are very similar to the coatings that are applied to headers from companies like Jet Hot Coatings.

So mrfixit58 how can aluminum be more thermally efficient if aluminum conducts heat better than iron? If you need to run a higher compression ratio with an aluminum head to get the same thermal efficiency that an iron head has than how can aluminum be more thermally efficient? A head that is more thermally efficient is a head that holds the heat in and does not transfer it to the cooling system.

When I stated “I got 177 HP @ 5000 RPM and 217 ft. lbs. of torque @ 3500 RPM and with a 9.7 to 1 compression ratio I got 209 HP @ 5000 RPM and 236 ft. lbs. of torque @ 3500 RPM". I used the same heads from the program even though the program can’t account for things like thermal efficiency. I also added tuned headers to the latter engine dyno.

I'm not trying to start a flame war either, just arguing my point so that we can come to an understanding here.

[This message has been edited by 88formula (edited 09-14-2000).]

No 88formulow, I do not need to generate flow data to prove this. GM has already done that and the 31.7% number was taken directly from the GM Performance parts catalog. The catalog is even online now, so if you need everything spelled out for you, go here:
https://www.spoperformanceparts.com/store/catalog/Product.jhtml?PRODID=192&CATID=190

Sarloc, I found that information on the GM performance web-site and I stand corrected. Here is a copy of the description from the web-site "These Gen III cylinder heads are used on late model V6/60º engines for improved performance. They feature an increase of 0.040" in intake valve diameter and a reshaped port for a flow improvement of 16.7% at 0.450" of valve lift. The exhaust port has been reshaped into a "D" port configuration for a flow improvement of 31.7% at 0.450" of valve lift".

http://www.spoperformanceparts.com

So I was right?

quote Originally posted by 88formula: The only advantage aluminum has over iron is weight savings and that’s it.

If thats true, then why are all the racers and their grandma's running alum heads with a required min weight? I'm not a mechanical engineer in thermodynamics, but I really think there is more to it than just weight savings IMO. Not trying to start flames either....

------------------

BBBAD V8

BBBAD GT

BBBAD 5.0

I've got a tired worn out 2.8 (stock). Will the 3.4 (I really don't care if it's got aluminum heads, cast heads, or Silly Putty heads) take my breath away or just feel like a stock Cavalier? (Only way to compare something as that's what my wife has.)

An easy test to tell which metal conducts heat (or cool) better. Take a hunk of aluminum and a hunk of ferrous metal, same size. Place both in an oven until both reach 400 degrees. Now, remove both and place on top of the oven to cool. Leave them standing for 3 minutes then grab BOTH one each with bare hands. The one that hits the floor first is the HOTTEST. I'm willing to bet it the ferrous metal. Aluminum conducts heat better and therefore cools faster. It will also let you run higher compression with the same or lower octane fuel rating. The higher the octane the longer it takes to burn. The longer it burns the more efficient the motor becomes (meaning less unburned fuel out the tailpipe). More effeciency means more power. Pick up a thermal dynamics book.

Roy

88formula,

In addition... the coatings you are referring to may help to reflecting heat but also help reduce hot spotting... which leads to premature detonation. Since aluminum conducts heat very well, the coating is usually not needed. While it may work to a certain degree, it can easily be burned off if you get too radical with the compression. In reality, iron is more thermally inefficient (conducts heat poorly).

When you mention; "By putting the heat back into the combustion process, the engine produces more power and is less prone to detonation" this is true. The heat should be referred to as waste heat. If you can convert waste heat into energy, it produces more work, more work means more efficiency, more efficiency means more power. All internal combustion engines produce waste heat and the key to a more efficient motor is to convert as much of the it into "work" as possible. Physics plays a large part in determining how much waste heat can be converted. By raising the compression more of the fuel is burned thereby increasing the efficiency and converting otherwise unburned fuel into power.

Finally, if you could really produce more power with an iron head, I believe that NHRA and NASCAR would be using them.

Roy

Maybe the racers using aluminum heads are using those thermal barrier coatings to increase the thermal efficiency of aluminum heads.

Mrfixit58 says "Aluminum conducts heat better and therefore cools faster”. Yes you are right. “It will also let you run higher compression with the same or lower octane fuel rating”. Combustion chamber design has a lot to do with this and not just the fact that the material is aluminum. “The higher the octane the longer it takes to burn”. Yes you are right about the fuel taking longer to burn but this is not a desirable thing. It leaves more time for things to go wrong like detonation. “The longer it burns the more efficient the motor becomes (meaning less unburned fuel out the tailpipe)”. The longer the fuel burns the more likely detonation will occur and the more oxides of nitrogen you get out the tailpipe. The longer the fuel burns the less compression you can run because of detonation. The longer the fuel burns the more ignition advance you have to have, which means more hydrocarbons find there way out the tailpipe. The longer the fuel burns the more the flame is in contact with the piston, combustion chamber and valves. The heads on the Chevy Vortec engine for example have fast burn combustion chambers, which makes the fuel burn faster. This makes it possible for the Vortec engines to run more compression with fewer emissions, they need less ignition advance so there are fewer hydrocarbons, and there is less chance of detonation to occur because of the quick burn rates. Most high performance heads have fast burn combustion chambers. “More efficiency means more power.” Yes more efficiency means more power and less emissions and better gas mileage, but I think we are talking about two different things when it comes to thermal efficiency. The concept is very, very simple. The more BTU'S from the fuel that are not taken away from the combustion event the more there will be to turn that crankshaft over harder. A thermally efficient head is not one that conducts heat away quickly; it is one that resist heat transfer from the combustion chamber into the coolant. "Pick up a thermal dynamics book". I think you are the one that needs to research this a little further Roy.

You say, “In addition... the coatings you are referring to may help to reflecting heat but also help reduce hot spotting... which leads to premature detonation. Since aluminum conducts heat very well, the coating is usually not needed”. There are a lot of racers out there that do think thermal barrier coatings are needed on aluminum heads and pistons. “While it may work to a certain degree, it can easily be burned off if you get too radical with the compression.” Those coatings protect up to 4200-degrees Fahrenheit. If your engine temperatures are that high you are going to melt more that just a coating. “In reality, iron is more thermally inefficient (conducts heat poorly)”. Remember that an internal combustion engine that is thermally efficient is one that converts as much of the BTU’ s from the fuel into mechanical energy. If this is true than if iron conducts heat poorly isn’t that what you want. You want as much heat to be converted into mechanical energy as possible, not to have it transferred into the coolant (wasted energy)
“When you mention; "By putting the heat back into the combustion process, the engine produces more power and is less prone to detonation" this is true. The heat should be referred to as waste heat”. How can the heat be wasted thermal energy if it is used to turn the crankshaft? “If you can convert waste heat into Mechanical energy, it produces more work, more work means more efficiency, (less waste means more efficiency) more efficiency means more power”. “All internal combustion engines produce waste heat and the key to a more efficient motor is to convert as much of the it into "work" as possible”. Correct! “Physics plays a large part in determining how much waste heat can be converted. You mean heat that is not wasted. By raising the compression more of the fuel is burned thereby increasing the efficiency and converting otherwise unburned fuel into power”. This is true as long as you don’t run into abnormal combustion.

I suppose we'll have to agree to dissagree.

Roy

All I know is that today's aluminum heads produce more power than yesterday's iron heads. That's what the Fiero heads are: yesterday's technology.
I think the only way we'll know the answer to which is really better is by having a set of iron heads identical to the aluminum heads and testing them in real world applications. Don't forget. The aluminum heads have the heart-shaped combusition chambers and splayed valves to improved fuel combustion.
One point about the heat. An aluminum engine can be kept cooler. That means you can probably fill it with more air+fuel. What happens in the combustion chambers happens so fast that I don't think it matters much there what the material is and wasted heat being transferred into the heads is going to be negligable. The alminum heads would have a bigger explosion due to having more air in there anyway. That's just my 2 cents. Also, I've driven a Cavalier 3.1 with the getrag 5 speed...it has aluminum heads and it felt stronger than my 3.4 GT all day long. It was an '89 so I think the axle gear was the same since our speeds in each gear matched up to our RPM...

Real world is what counts, not just they physics of one aspect of the process.

I think you are comparing apples to oranges. The two heads you are talking about are completely different. The discussion I believe was basically between two identical heads, with iron/alum being the only difference. Its hard to say a caviler motor with alum heads is stronger than the fiero motor just becuase of the heads, because there are more than likely some other major differences between the two except the heads (cam/timing/intake/etc).

Alright i'm no rocket scientist here, but you also have to look at the flow charactisics of the heads. Sometimes too much flow is not good! You have to match your cam shaft to the flow charactics of your cylinder heads. Most times in fieros, you can't put a super hot cam in because you run into computer problems with vacuume and such and you could also loose your power brakes. I'd love to have a cam with a higher duration but the computer wouldn't like that very much.

------------------
Mike LeCompte
86 Fiero GT 3.2L w/ Nitrous

Well, the Cavalier was stock and my engine is modified to kingdom come...