Assuming someone here has done the Allante intake, N* pistons, custom cam, etc.
Any dyno numbers or track times? Just curious.

4.9 turbo built by PBJ here on the forum was the most powerful. Nobody has taken a 4.9 to its limits to see whats truely possible. What I mean by limits is upgrading til the first weakest link breaks, strengthing it, and repeating until something like the crank or block explodes.

Its been shown that the 4.9 is capable of low 12 to high 11's without reaching a failure point or becoming unreliable.

The highest dollar NA build (built by Rick Stewart, GT here on the forum) was never tuned properly to take advantage of the upgrades. So far, we just don't know how far it can be taken. Its likely we never will either. The 4.9 is mostly used as a reliable and cost effective solution to get more out of a fiero without breaking the bank. If you want tp upgrade to lots more power a different platform is almost certainly a better way to go. Its a great motor for what it is. It is not a great motor for what it can be. It all comes down to the 4.9's single biggest hinderance... the heads. They were squashed to fit inside the relatively low height of the caddy engine bays. This created an issue in making any significant power. The total lack of any aftermarket heads, throttle body's, or intakes only add insult to injury.

Don't get me wrong, I love my 4.9. I drive it everyday and am quite satisfied with it. It has power whenever I need it. It puts all stock fiero engines to shame easily. However, if I needed something more then a daily driver I would look elsewhere. Most other 4.9 owners will tell you the same.

[This message has been edited by Fieroseverywhere (edited 01-11-2011).]

quote Originally posted by BigGuyTinyCar: Assuming someone here has done the Allante intake, N* pistons, custom cam, etc. Any dyno numbers or track times? Just curious.

My friend Robert did an allante intake, P&P heads, larger SBC intake valves, .50" lift cam, N* pistons, polished intake and exhaust, 1.7 roller rockers with LS1 springs, all on his 4.9L, and he is currently working on getting it dialed in and tuned. after it is "street tuned" for both power enrichment and lean cruise, he will be taking it to the dyno for "fine tuning"... when we have the result, i will post the numbers here in the forum.

one thing is for sure, the valvetrain upgrade combined with the headwork has completely changed the motor, it now pulls HARD all the way to 6500 ( rev limit set at 6500). with the tall deville highway gears, the 1-2 shift happens at like 45 mph at WOT, pretty f-ing cool...

Racingman24 has the 4.9 with Allante intakes, fully P&P heads and Delta cam in his 88 base coupe... supposedly, it runs now too... if only he would drive it... I would love to see what it makes on a dyno naturally aspirated.

[This message has been edited by carbon (edited 01-11-2011).]

quote Originally posted by carbon: Racingman24 has the 4.9 with Allante intakes, fully P&P heads and Delta cam in his 88 base coupe... supposedly, it runs now too... if only he would drive it... I would love to see what it makes on a dyno naturally aspirated.

any cam and head work change needs a full retune on that motor, because it totally changes the flow characteristics....

If you built one absolutely to the nines and did everything right, including fabbing long tube headers from scratch, 300 HP all motor would still be an achievement. The heads are *that* bad.

As far as turbo goes, a similar build might be good for 400-450 HP on pump gas, @$$uming that the turbo is well selected. I don't believe PBJ's was.

Modding a 4.9 is a tough sell when you can get the same results for less effort and expense out of a 3500 V6.

Now there is a company that makes BILLET heads for Ford 302's. They flow something like 400 CFM on the intakes. Does anyone know what the bore centers of the 302 and 4.9 are?

quote Originally posted by Will: If you built one absolutely to the nines and did everything right, including fabbing long tube headers from scratch, 300 HP all motor would still be an achievement. The heads are *that* bad. As far as turbo goes, a similar build might be good for 400-450 HP on pump gas, @$$uming that the turbo is well selected. I don't believe PBJ's was. Modding a 4.9 is a tough sell when you can get the same results for less effort and expense out of a 3500 V6. Now there is a company that makes BILLET heads for Ford 302's. They flow something like 400 CFM on the intakes. Does anyone know what the bore centers of the 302 and 4.9 are?

Rick Stewart had only the mild cam regrind from Delta, and his engine put down 234hp and 304tq to the ground in a completely untuned state. Assuming an 18% drivetrain loss, that equals 285 HP and 371 lb/ft TQ at the flywheel... if he was tuned properly, i guarantee that 300 HP at the flywheel was achievable on his motor. Yeah, i know the 4.9L will never be a major HP contender, but it has tons of TQ, and in short distances, TQ wins races.

now with robert's engine build, he has a more aggressive cam, and judging from Rick Stewart's thread pics, better flowing heads than rick as well. i was amazed at how much material could be removed safely from the ports on the 4.9L heads when Robert had his P&P done...the ports were much larger, and he had larger intake valves installed, which really helped... i don't know HOW MUCH of an increase in flow it was, but it was significant to say the least, the motor pulls hard and breaths very well all the way up to 6500 rpm now. It's a shame he didn't have the heads flow tested before he installed them on the engine....

out of curiosity, whats the name of the company that casts those 302 heads Will?

[This message has been edited by stickpony (edited 01-11-2011).]

quote Originally posted by stickpony: Assuming an 18% drivetrain loss out of curiosity, whats the name of the company that casts those 302 heads Will?

It was a stick right? 10% would be much more realistic.

They don't cast them. They cut them. Can't find my username and password right now, but I think they were shown on www.gofastnews.com


EDIT: http://www.gofastnews.com/s...ht=billet+ford+heads

http://www.ultrapromachining.net/

Trick Flow also does something similar: http://www.trickflow.com/pr...rportbilletcylinder/

http://www.totalflowproduct...=view&id=9&Itemid=14

[This message has been edited by Will (edited 01-11-2011).]

quote Originally posted by Will: It was a stick right? 10% would be much more realistic. They don't cast them. They cut them. Can't find my username and password right now, but I think they were shown on www.gofastnews.com EDIT: http://www.gofastnews.com/s...ht=billet+ford+heads http://www.ultrapromachining.net/ Trick Flow also does something similar: http://www.trickflow.com/pr...rportbilletcylinder/ http://www.totalflowproduct...=view&id=9&Itemid=14

10%? hahah come on man, seriously, are you joking? the average manual tranny 4.9 dyno numbers i have seen are all right around 155-160 HP and 210-220 lb/ft TQ, coming from a stock 4.9L engine, i would say that is more like a 20%-22.5% loss, however, i said 18% to be conservative, since most MODERN FWD manual trannies waste about 16-18%.

quote Originally posted by stickpony: 10%? hahah come on man, seriously, are you joking? the average manual tranny 4.9 dyno numbers i have seen are all right around 155-160 HP and 210-220 lb/ft TQ, coming from a stock 4.9L engine, i would say that is more like a 20%-22.5% loss, however, i said 18% to be conservative, since most MODERN FWD manual trannies waste about 16-18%.

Nope, not joking at all. FWD manual transmission is around 10%. Go read an NSX forum. There's nothing special about that transmission, yet they claim 11%. There's basically nothing in a FWD stick box to lose power. An automatic has a pump and extra moving parts, and a longitudinal driveline has a hypoid bevel final drive. The FWD stick doesn't have either of those power-sapping characteristics, as well as typically having a pretty light flywheel (14# is quite light for a V8).

As for the 4.9, it seems to suffer from SBC Fiero syndrome in that it rarely makes rated power.

[This message has been edited by Will (edited 01-13-2011).]

quote Originally posted by Will: Nope, not joking at all. FWD manual transmission is around 10%. Go read an NSX forum. There's nothing special about that transmission, yet they claim 11%. There's basically nothing in a FWD stick box to lose power. An automatic has a pump and extra moving parts, and a longitudinal driveline has a hypoid bevel final drive. The FWD stick doesn't have either of those power-sapping characteristics. As for the 4.9, it seems to suffer from SBC Fiero syndrome in that it rarely makes rated power.

For those of us that are uneducated, is the power rating of an engine at the flywheel what you can REALLY expect out of an engine, especially used? I imagine gm has been being generous with their numbers like everyone else. Hell, Ford has been blatantly lying about their performance cars' output for a while from what I can tell. I could be completely wrong I suppose, but I doubt engines get rated at exactly what they actually put out very often...

quote Originally posted by MadDanceSkillz: For those of us that are uneducated, is the power rating of an engine at the flywheel what you can REALLY expect out of an engine, especially used? I imagine gm has been being generous with their numbers like everyone else. Hell, Ford has been blatantly lying about their performance cars' output for a while from what I can tell. I could be completely wrong I suppose, but I doubt engines get rated at exactly what they actually put out very often...

Actually, GM has a history of UNDER rating motors to lower insurance costs!

quote Originally posted by MadDanceSkillz: For those of us that are uneducated, is the power rating of an engine at the flywheel what you can REALLY expect out of an engine, especially used?

You can imagine a lot, but the facts remain what they are.
Yes, a modern EFI engine should make it's rated output unless it's blowing oil smoke and has no compression. The ability of EFI to meter fuel better than a carb keeps the bores from being washed down on cold starts and prevents most bore wear. It's very common for EFI engines to go over 200K miles with visible hone marks on the bores.

I think that 4.9's and Northstars both suffer computer problems that keep them down from rated output in most installations with the factory computer.

The 4.9 is a cheap and easy swap, but if you're after cheap and easy performance, do the L67 instead. If you insist on a performance V8, a 350 Chevy can do 400 HP cheaper than a 4.9 can do 300, even figuring the extra $ for the adapter plate.
If you want more than 400 HP, the best bang for the buck is the LS4.

quote Originally posted by Will: Nope, not joking at all. FWD manual transmission is around 10%. Go read an NSX forum. There's nothing special about that transmission, yet they claim 11%. There's basically nothing in a FWD stick box to lose power. An automatic has a pump and extra moving parts, and a longitudinal driveline has a hypoid bevel final drive. The FWD stick doesn't have either of those power-sapping characteristics, as well as typically having a pretty light flywheel (14# is quite light for a V8). As for the 4.9, it seems to suffer from SBC Fiero syndrome in that it rarely makes rated power.

dude, dyno numbers dont lie when they consistently show otherwise. IF the FWD manula trannies we use on our engine swaps only lost 10%, then ALL 4.9L manual tranny fieros would dyno at 180HP, and NONE of them do, not one. show me a stock 4.9L engine mated to a fiero manula tranny that does that, and i will eat my words.

and OF COURSE these NSX guys all have linear graphs to show the power/TQ curves on an engine dyno compared to a wheel dyno!? dude, seriously, anybody can CLAIM anything, the fact is that power loss due to transmissions in the FWD realm is no different than the RWD realm. yes, automatics loose more there is no arguement there. When comparing FWD to RWD though there is also more parasitic loss from the CV axles additionally to the transmission itself, considering they each have two U-joint style connections, so that has to be added to the loss by just the transmission alone. each CV axle has two Universla style joints, thats two more than a RWD car. the loss is also INCREASING with engine output, so the transmission looses the most power at the peak of an engine's TQ curve.

tell you what Will, you show me hard numbers, like the differing numbers on a dyno of the same engine mated to an automatic vs a manual, or engine dyno vs wheel dyno for any manual tranny setup on a fiero, then i will start to believe you. Until then, the loss is 18%.

last time i checked, the manual tranny fiero's didn't have 15 more HP than the automatics in stock form, they all dyno around the same numbers.

quote Originally posted by Isolde: The 4.9 is a cheap and easy swap, but if you're after cheap and easy performance, do the L67 instead. If you insist on a performance V8, a 350 Chevy can do 400 HP cheaper than a 4.9 can do 300, even figuring the extra $ for the adapter plate. If you want more than 400 HP, the best bang for the buck is the LS4.

I'm not so sure that the LS4 swap will give you the best bang for the buck. I tend to think that a ZZ4 rated at 355HP and 405TQ would be a less expensive swap with fairly respectable performance. You might want to talk to Oreif about this since he did this swap and seems to be quite pleased with the results.

~ Bob

edited to correct spelling.

[This message has been edited by FieroBobo (edited 01-13-2011).]

quote Originally posted by FieroBobo: I'm not so sure that the LS4 swap will give you the best bang for the buck. I tend to think that a ZZ4 rated at 355HP and 405TQ would be a less expensive swap with fairly respectable performance. You might want to talk to Oreif about this since he did this swap and seems to be quite pleased with the results. ~ Bob edited to correct spelling.

What planet are you from? A new ZZ4 runs $3500. Only practical way to get one. A good used LS4 runs $1400. Again, only practical way to get one. To get 450 HP from a ZZ4 can't be done without a head swap, and a cam, and an intake manifold. Or nitrous, but that breaks trannies. So. Heads: $700 installed, minimum. Cam: $350 installed, minimum. Intake manifold: $ 300 installed, minimum.
To get there with the LS4 requires nothing more than a cam swap and a tune. Cam, under $500 installed. Tune $ 500, maximum. Call it a half price hero. No, wait, forgot it needs pushrods. Add another $100 to be sure. Still.

I don't know why people expect big HP #'s from a 4.9 when it's rod to stroke ratio is something like 1.5.
The motor is not designed to be rev'd highly. Heads and intake may free up some top-end but the motor was designed to be a stump-puller from 1200-4500 rpm.

Can't we leave it at that? Why add a jetpack to a turtle?

If you want to spin it faster, destroke it and upgrade the valve-train.

Heads and intake are used to optimize efficiency over a certain rpm range but they can only do so much. I think even the Northstar uses a 1.7x ratio. For comparison a Honda S2000 has a 2.0 ratio. That motor spins to 9000+rpm but ofcourse has no bottom end torque, plenty of HP.

From the early 4.9 swaps most of the dynos were in the 175 hp neighborhood. I believe the getrag consumes 25 hp ~ 5000rpm. So those seem right to me. It doesn't matter what engine is mated to a transmission...at a given rpm, that transmission/driveline will require X amount of power to be spun at that speed. It's not a % of engine power. For instance, a 50 FWHP engine could spin a getrag to 5000rpm but only do 25 hp at the wheels. It wouldn't be 41 rwhp (assuming 18% loss) it would be flywheel hp - driveline loss at a given rpm. I hope that makes sense. At 2000 rpm, the driveline loss may only be 10hp. The only way to really measure driveline losses is to do a flywheel dyno and a traditional chasis dyno and compare the results.

Am I way off on my 25hp #?

A 2.8 dynos at 115 hp (140 flywheel)
A "stock" 3.4 dynos at 135 hp (160 rated)
A 3.4 TDC dynos at 185 hp (210 rated) (again stock)
The list goes on and the difference in motors in stock form on a getrag has always been about 25hp. Engine total power is irrelevant.
People complain about the old TPI 350's in Fieros...they were rated at 220hp from the factory and still have dyno'd under 200 rwhp...yet people laugh when they see a sub-200rwhp 'Archie V8' as if it's Archie's fault...

Peace.

quote Originally posted by stickpony: SFI keep the caddy motors very clean man, even a high mileage 4.9L puts down damned near the reated power, sometimes more, as people have stated before, GM always underrates their motors slightly..

Huh. Well, now I know, glad I made a stupid comment so I could be corrected. Learn something every day, I guess.

For what it's worth, I had a Getrag car at slightly over 200whp, and a 4.9l auto with a few small mods. I thought the Getrag car would be faster, but it wasn't. Must have been the TQ difference. I think the 4.9l makes close to 100 more TQ than HP from the factory.

A long time ago I started screwing with a guy from RFT about the 4.9l running 13's. His tantrums are hilarious, and he still talks about it even though I got tired of the game something like a year ago. Same guy that starts 3 Archie bash threads every day. From what I can tell, he spends his days trolling Pennock's in some kind of demented effort to rid the world of evil. It's amazing how much hate people throw at the 4.9l. It isn't a piece of junk, it's really fast as far as 99% of people are concerned, and I'm unaware of another V8 Fiero swap that can match the gas mileage it gets other than maybe a DOD LSX. I've got a beefed up 3800SC Series III now, and it's way faster, but that doesnt mean I won't do another one someday. Going fast in a straight line isn't the only thing a Fiero is good for, and the 4.9l probably makes a better autox engine than the 3800sc does, being that it's a LOT lighter and makes great lowend.

Somebody should push it to the limits we apparently don't really know about yet, everyone I've talked to that's been inside one says it's an incredibly well built motor and looks as if it was built for boost.

[This message has been edited by MadDanceSkillz (edited 01-13-2011).]

Not sure why drivetrain efficiency keeps coming up, but in the world of Camaros, Mustangs and light pickups, it is a percentage.
Shall we discuss why?
Manual transmissions don't use straight cut gears. So there's some power loss there, from thrust loading. And while roller bearings and good synthetic lube reduce the loss, there still is loss. More power = more thrust loading = more loss.
Pretty much the same story with live axles, but the ring and pinion design eats more power per pressure unit applied. Plus the lube must be even thicker, even if synthetic.
Automatics also have the angle cut gears like manuals, but in a thinner lubricating fluid. However, automatics add 2 other losses. The torque converter, and the fluid pump. Aftermarket converters can be built strong enough to survive being locked at WOT, but stock, they unlock at WOT, as it should be for best RWTQ.
The AT pump eats a set amount of HP at a set RPM, true enough. But to handle more power typically means raising pressure, so the pump takes more power.
The end result is that Camaros and Mustangs with synthetic lube in the axle, will lose about 12-14% if manual, and about 22-23 % if stock automatic.
Fieros don't have the ring and pinion, at least not in the manuals. So there should be a bit less loss.

[This message has been edited by Isolde (edited 01-13-2011).]

quote Originally posted by stickpony: GM always underrates their motors slightly..

...and in the case of the F-body LS1s, severely. Those cars are rated at 305-310 HP (depending on year) and most of them put down
about 290-310 RWHP (some even more). The truth is, although they had different cams and programming than the LS1 Corvette, they all
had about the same crank HP (somewhere in the 350-370 range).

Friction loss is documented in the Getrag service manual. in 1st, 2nd, 3rd, its around 1N-M 4th and 5th are between 2-3. N-M. So friction losses are practically non-existent. They were much higher in the 4 speed, but Im talking 4 N-M in 4th which is still close to nothing. I assume these tests were done with the 140 HP engine that the model transmission was introduced with. These are obviously pre-gearing torque losses, the type that would have a direct correlation on a dyno.

Now, if you include tire friction, and the having to accelerate the mass of the flywheel, the transmission, axles, wheels and brakes. On a load acceleration dyno, these factors start to add up to some large losses at the wheel. (10-20%?) But... on a brake type dyno, the points are sampled as a load at a specific RPM, without the factor of acceleration. The true engine numbers start to come out minus only friction losses, which are VERY low on a FWD manual to begin with. So when considering dyno loss, on a wheel acceleration dyno, friction is #2, Accelerated mass is #1. On a dyno that uses a brake, mass gets factored out since acceleration is barely occurring.

Which dyno numbers should you trust? If you want to compare your results to those of a factory HP rating, you need to dyno on a brake type dyno. If you want to measure how fast your car will be, use a acceleration type dyno. Believe it or not, you can have two cars that weigh the same, and put out the same power on a brake type dyno, actually pull different numbers on an acceleration dyno. The one having the lighter drivetrain will do better, and on the track, will be faster.

I don't know why I felt the need to contribute to this argument, It doesn't even relate to the original post!

Ya know, a Getrag 282 NOT installed in a car, can be spun by the power of one real live horse, like you find on a farm. It's not until you add the resistance of the Fiero that the HP drain climbs to 25 horses. Adding power is like adding resistance.
If a 200 HP engine takes 25 HP, then a true 400 HP engine should take nearly 50 horses.
It won't be that linear, but it's like putting 6000 pounds on a 200 HP engine.

[This message has been edited by Isolde (edited 01-13-2011).]

it is what it is, everybody has there opinion here. when robert gets done tuning his fully built to the max NA 4.9L ( now bored to 5.1L with the N* pistons ), i'll post the numbers

http://www.chrfab.com/Engines.htm

We have custom pistons, rods, cranks, cams, and other modifications such as belt driven blowers and exhaust driven turbo chargers for the Northstar and Aurora engines. How much power do you want to make?
A Weiand supercharger on our manifold puts out 600 HP with very conservative boost of 9 psi and 525 HP at 5.5 psi. These engines with rods, pistons, rotating assembly balance, head work, cams, springs, retainers, head studs, etc. runs approximately $18K

This is a 3300 Whipple supercharger installation with enough air for 20 lbs of boost, about 800 hp!

quote Originally posted by Isolde: R/S ratio has nothing to do with rpm range. Ideally, it should be higher for more rpm, but when we have 6.135-rod, 4.25"-stroke BBCs making power to 7000 rpm, with good heads but no power adder, it's fun to realize it has an r/s of 1.4435:1. You want a low-rpm engine with a good R/S? How about the 318 Mopar? 1.85:1 They can be built to rev, by using good heads, but the smog versions were low rpm torquers.

And you can (theoretically--I haven't built one yet) use 6.385 BBC rods with SBC bearing bores (Eagle makes them) with a 3" stroke crank in a SBC and have a 2.13 (2.1283 to keep Isolde happy) rod ratio. While that will reduce side loading frictional loss, it won't do squat for power...

More on driveline loss later...

[This message has been edited by Will (edited 01-13-2011).]

:-)

quote Originally posted by Isolde: Ya know, a Getrag 282 NOT installed in a car, can be spun by the power of one real live horse

Very good point for those that say a MT always sucks up a set amount of HP, I hear that crap all the time (Especially from DSM guys)...if that was true I couldn't spin the transmission by turning a wheel while the rear end was jacked, wouldn't be strong enough.

quote Originally posted by stickpony: it is what it is, everybody has there opinion here. when robert gets done tuning his fully built to the max NA 4.9L ( now bored to 5.1L with the N* pistons ), i'll post the numbers

Yes, please do. I'm very curious. I don't think I'll ever break into my 4.9, because I love what it is right now (a torque monster) and mine
will never see a race track. If I put any money into this car it will be into suspension and possibly interior cosmetics.

quote Originally posted by Gokart Mozart: http://www.chrfab.com/Engines.htm We have custom pistons, rods, cranks, cams, and other modifications such as belt driven blowers and exhaust driven turbo chargers for the Northstar and Aurora engines. How much power do you want to make? A Weiand supercharger on our manifold puts out 600 HP with very conservative boost of 9 psi and 525 HP at 5.5 psi. These engines with rods, pistons, rotating assembly balance, head work, cams, springs, retainers, head studs, etc. runs approximately $18K This is a 3300 Whipple supercharger installation with enough air for 20 lbs of boost, about 800 hp!

18K for 600 HP is insane. L67 can do it for like a fifth of that cost. So can LS4 with a T76.

quote Originally posted by MadDanceSkillz: Somebody should push it to the limits we apparently don't really know about yet, everyone I've talked to that's been inside one says it's an incredibly well built motor and looks as if it was built for boost.

Back about 10 years ago there was a guy named Dvorak (Dvorak2 ebay ID) that had a full on 4.9 drag racing effort (in a full size caddy of all things). He had custom cams, custom heads and did some work to the block. He got away from the 4.9 sceen around 2002/2003 and went to the N* platform. I picked up one of his custom camshafts in 3/02 as he was liquidating his 4.9 stuff and could have had a set of heads as well, but they were quite expensive... but never did anything with it and have no idea where it is today (2 moves later... it probably got tossed).

If you are serious about building power with the 4.9... you need to track this guy down and see if he has any of his parts left over.

Here is their business:
http://www.dvorakmachine.com/

[This message has been edited by fieroguru (edited 01-15-2011).]

quote Originally posted by fieroguru: Back about 10 years ago there was a guy named Dvorak (Dvorak2 ebay ID) that had a full on 4.9 drag racing effort (in a full size caddy of all things). He had custom cams, custom heads and did some work to the block. He got away from the 4.9 sceen around 2002/2003 and went to the N* platform. I picked up one of his custom camshafts in 3/02 as he was liquidating his 4.9 stuff and could have had a set of heads as well, but they were quite expensive... but never did anything with it and have no idea where it is today (2 moves later... it probably got tossed). If you are serious about building power with the 4.9... you need to track this guy down and see if he has any of his parts left over. Here is their business: http://www.dvorakmachine.com/

do you remember the specs on the camshaft??

quote Originally posted by stickpony: 10%? hahah come on man, seriously, are you joking? the average manual tranny 4.9 dyno numbers i have seen are all right around 155-160 HP and 210-220 lb/ft TQ, coming from a stock 4.9L engine, i would say that is more like a 20%-22.5% loss, however, i said 18% to be conservative, since most MODERN FWD manual trannies waste about 16-18%.

You're assuming that these engines are making 200 HP at the flywheel...

quote Originally posted by stickpony: dude, dyno numbers dont lie when they consistently show otherwise. IF the FWD manula trannies we use on our engine swaps only lost 10%, then ALL 4.9L manual tranny fieros would dyno at 180HP, and NONE of them do, not one. show me a stock 4.9L engine mated to a fiero manula tranny that does that, and i will eat my words. and OF COURSE these NSX guys all have linear graphs to show the power/TQ curves on an engine dyno compared to a wheel dyno!? dude, seriously, anybody can CLAIM anything, the fact is that power loss due to transmissions in the FWD realm is no different than the RWD realm. yes, automatics loose more there is no arguement there. When comparing FWD to RWD though there is also more parasitic loss from the CV axles additionally to the transmission itself, considering they each have two U-joint style connections, so that has to be added to the loss by just the transmission alone. each CV axle has two Universla style joints, thats two more than a RWD car. the loss is also INCREASING with engine output, so the transmission looses the most power at the peak of an engine's TQ curve. tell you what Will, you show me hard numbers, like the differing numbers on a dyno of the same engine mated to an automatic vs a manual, or engine dyno vs wheel dyno for any manual tranny setup on a fiero, then i will start to believe you. Until then, the loss is 18%. last time i checked, the manual tranny fiero's didn't have 15 more HP than the automatics in stock form, they all dyno around the same numbers.

Dyno numbers don't lie, but they do lend themselves unscrupulously well to misinterpretation.
I mentioned the NSX to simply be illustrative of the fact that I'm not way out in left field and there are other people who agree with me.
Would you mind linking some of these 4.9 stickshift dyno threads?
Have you had a 4.9 on an engine dyno to verify that they are making 200 HP as installed in a Fiero? Since that's the standard of proof you're asking of me, that's the standard of proof to which you must comply as well.

Front wheel drive transmissions are very different than rear wheel drive transmissions. Obviously the loss is much different as well. The big factor between front and rear wheel drive is the hypoid bevel final drive mesh. As Isolde mentioned, this mesh consumes significant power. It's much more lossy than a simple spur gear like the FD in a 282, F23 or F40. Also, RWD drivelines have a LOT more bearings, shafts and seals than FWD drivelines.

Bottom line, the 282's simplicity means that it has low loss. It has two spur gear meshes to consume power and *BASICALLY NOTHING ELSE*.

quote Originally posted by stickpony: proper programming for the 4.9L computers has been around for a long time now. as far as fuel trim goes, as long as the power steering input is taken care of and the chip is programmed, the engines run very cleanly and have ZERO issues. rockcrawl, until recently was doing chips for people as far back as 2002, and i have been doing chips for people for 4 years now, so i would say your point raised is MOOOOT.

Ever had one on an engine dyno to prove that it's making rated power?

quote Originally posted by lou_dias: From the early 4.9 swaps most of the dynos were in the 175 hp neighborhood. I believe the getrag consumes 25 hp ~ 5000rpm. So those seem right to me. It doesn't matter what engine is mated to a transmission...at a given rpm, that transmission/driveline will require X amount of power to be spun at that speed. It's not a % of engine power. For instance, a 50 FWHP engine could spin a getrag to 5000rpm but only do 25 hp at the wheels. It wouldn't be 41 rwhp (assuming 18% loss) it would be flywheel hp - driveline loss at a given rpm. I hope that makes sense. At 2000 rpm, the driveline loss may only be 10hp. The only way to really measure driveline losses is to do a flywheel dyno and a traditional chasis dyno and compare the results. Am I way off on my 25hp #? A 2.8 dynos at 115 hp (140 flywheel) A "stock" 3.4 dynos at 135 hp (160 rated) A 3.4 TDC dynos at 185 hp (210 rated) (again stock) The list goes on and the difference in motors in stock form on a getrag has always been about 25hp. Engine total power is irrelevant. People complain about the old TPI 350's in Fieros...they were rated at 220hp from the factory and still have dyno'd under 200 rwhp...yet people laugh when they see a sub-200rwhp 'Archie V8' as if it's Archie's fault... Peace.

Can you link to such a dyno thread (175 HP?)

quote Originally posted by Fierobsessed: Friction loss is documented in the Getrag service manual. in 1st, 2nd, 3rd, its around 1N-M 4th and 5th are between 2-3. N-M. So friction losses are practically non-existent. They were much higher in the 4 speed, but Im talking 4 N-M in 4th which is still close to nothing. I assume these tests were done with the 140 HP engine that the model transmission was introduced with. These are obviously pre-gearing torque losses, the type that would have a direct correlation on a dyno.

Involute profile gear teeth slide across each other in the radial direction as the gears turn. This is the source of frictional loss. Increasing the torque increases the contact force at the teeth, which increases the force required to make them slide across each other. Thus the reduction in torque due to friction is proportional to the torque being passed by the transmission. Frictional loss is a percentage. Viscous loss due to churning of the fluid is more complex. I can make a WAG that it's related to the square of RPM. The "flywheel effect" is related to both the RPM rate AND the square of the gear ratio.

Those 1-4 newton-meter numbers are what it takes to spin the transmission by itself with no load.

The helical cut on the gears has essentially nothing to do with frictional loss. There is no movement in the direction that the axial force is applied, so there is no power consumed. It is possible that the end loading may increase the frictional loss in the shaft bearings a miniscule amount, but that won't be significant.

[This message has been edited by Will (edited 01-18-2011).]

I have a buddy who just finished rebuilding his 4.9 and dropped it into a Citation. He's done quite a bit of work to it, specifically with the heads.

His description isn't as exaggeratory as it should be, because there's a lot he's not mentioning here. He actually sent out his cyl heads to a special race shop somewhere, to this guy who specialized in 4.9s... (the guy is now retired, but he got him to do the work, but it took the guy like 4 months). The guy really hogged out the cyl heads. The motor pulls hard ALL the way to 6,500 rpms... and he had all the pieces properly balanced to be able to handle well above that rpm, although he doesn't get much power past that at all.


Here's his description:

quote On the Heads - Port & Polished intake & exhaust ports, 1.7 to 1 ratio Full roller rocker arms, Oversized stainless intake valves from SBC, LS1 Beehive Valve springs - good to 6800 rpm Redline, Comp Cams hardened performance pushrods. In the Block - Custom ground Camshaft from Delta Cams - .500 lift, Piston sleeves bored .040 over, & Northstar Pistons for increases compression ratio. Extras - Ported Exhaust Manifolds, Allante Intake = super flow, and MSD ignition.

Here's the head work: http://www.petacar.org/members/Coper/heads.htm

And here's everything else about his motor: http://www.petacar.org/memb...oper/engine_mods.htm

------------------
Todd,
2008 Jeep Patriot Limited 4x2
2002 Ford Explorer Sport 2dr 4x2
2002 Ford Crown Victoria LX
1987 Pontiac Fiero SE / V6
1973 Volkswagen Type-2 Transporter

quote Originally posted by Will: Involute profile gear teeth slide across each other in the radial direction as the gears turn. This is the source of frictional loss. Increasing the torque increases the contact force at the teeth, which increases the force required to make them slide across each other. Thus the reduction in torque due to friction is proportional to the torque being passed by the transmission. Frictional loss is a percentage. Viscous loss due to churning of the fluid is more complex. I can make a WAG that it's related to the square of RPM. The "flywheel effect" is related to both the RPM rate AND the square of the gear ratio. Those 1-4 newton-meter numbers are what it takes to spin the transmission by itself with no load. The helical cut on the gears has essentially nothing to do with frictional loss. There is no movement in the direction that the axial force is applied, so there is no power consumed. It is possible that the end loading may increase the frictional loss in the shaft bearings a miniscule amount, but that won't be significant.

dude, frictional loss isn't a percentage at all rpms, it is INCREASING with the rpms at a linear rate, peaking at close to 18%. So, now you are calling GM liars and their documentation in their own manual is a lie? come on man.

as to your Dyno's Will, yeah i don't KNOW that every engine out there would hit 200 HP on an engine dyno, but it is a safe bet that when many engines both here and in the cadillac forums consistently graph with similar numbers that it is more than likely accurate. i HIGHLY doubt that GM rated a 180HP to be 200HP in a Cadillac, someone would have figured it out, whether it be a magazine.

another thing you are entirely overlooking are the CV axles, which absorb ALOT more power than straight axles from a RWD car. CV joints are very loose and have alot of play in them, and there are two in each axle on each side.

and yeah, i don't have studied numbers to tell you how much power they lose, but i guarantee you it is alot more than the axles in RWD cars. simple logic would dictate that.

You ask people to post proof, but until you post proof that DISPROVES us, your claims are just as baseless as ours supposedly are. get a clue.

Modern RWD manuals, plus modern RWD R&Ps, add up to about 12-14% loss. Not even the CTD is 18%, even without synthetic lubes.
NO way is FWD / Fiero more than that. The CVs aren't costing enough to measure. Get them at an angle, it'll still take less than 1 HP to squish the grease around. Even if the grease is cold. If yours have slop, replace them.
18% might be a safe figure for a transverse automatic, since RWD auto with a R&P is around 22-23%.
But transverse again has no R&P, so less loss.
To test for slop, clamp vise-grips to the middle of the shaft, then wedge those against something. Then try to turn the wheel.
This slop still won't eat power unless there is binding, but that'll break stuff.