I guess I am calling on a Fiero history Buff for this question. During the mid 80s the IMSA Fiero that had the SD4 was the performance combination at the race track. My question is really two parts, did they ever do any racing with the 2.8 v6, and why did GM go with the 2.8v6 as the performance engine, and not a build up version of there 2.5?

The 2.8 WAS the high performance street engine from GM in those days (short of a V8). It was the logical choice. The 2.5 and the SD4 have very little in common, and the SD4 would never pass anything resembling an emissions test. There was some racing with the 2.8s, but not a huge amount.

quote Originally posted by Fastback 86: The 2.8 WAS the high performance street engine from GM in those days (short of a V8). It was the logical choice. The 2.5 and the SD4 have very little in common, and the SD4 would never pass anything resembling an emissions test. There was some racing with the 2.8s, but not a huge amount.

At least with the track cams and injector (or was it carbed?). Adding about 50 lbs of iron doesnt magically kill the emmisions.

If I remember correctly, the IMSA Fieros used the 2.8. I believe some of the Pontiac Spices in the Camel Lights division used them too. My guess is that using the 2.5 as a base, to include the SD, would be too expensive and unreliable for racing as compared to the 2.8. Same as with our stock Fieros. If you want more power out of your four cylinder, you can modify it and get a certain horsepower out of it. But it's expensive and the motor will probably break quickly. Or you could start with the stock 2.8 with as much HP as you get out of a heavily modified four and have a better, more reliable platform to start with and get more HP out of it.

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Whade' "The Duck Formerly Known As Wade" Duck
'87 GT Auto
'88 Ferrario
'84 Indy

quote Originally posted by whadeduck: If I remember correctly, the IMSA Fieros used the 2.8. I believe some of the Pontiac Spices in the Camel Lights division used them too. My guess is that using the 2.5 as a base, to include the SD, would be too expensive and unreliable for racing as compared to the 2.8. Same as with our stock Fieros. If you want more power out of your four cylinder, you can modify it and get a certain horsepower out of it. But it's expensive and the motor will probably break quickly. Or you could start with the stock 2.8 with as much HP as you get out of a heavily modified four and have a better, more reliable platform to start with and get more HP out of it.

from what i read they used SD4s

Ok here is the scoop from someone who was at the track all years Pontiac Raced the Fiero.

IMSA cars

GTU the stock style bodied cars all ran Super Duty 4 cylinder engines

GTO had one V6 stock style bodied car and it ran a 4.3 Chevy 90 degree V6 [Red GT just saw the car and can back this up]

GTP Light prototype cars built by Spice enginering all ran Super Duty 4 cylinders.

GTP Spice Prototypes were all call Firebird GTP's They were all powered with Small block Chevy V8's

GTP Spice Buick's used after Pontiac left were 3.8 based V6 engined.

GTP Light Acura Spice was a V6, I still have the BFG poster on the wall.

The differance in the classes were weight of the cars the engine size. That is why the Fiero GTP light and the Fierbird GTP were nearly the same car but the Bird had a bigger engine and weight was more.

NHRA had several Super Duty 4 cylinder Fiero's

The only place I remember a 2.8 Fiero racing was in SCCA show room Stock with Herb Adams. they did not race much.
Also some SCCA rally events had a few V6 and 4 cylinder cars

The only real racing for the 2.8 was with the Cars and Concepts Berreta and Z24 cars. They raced in what was once the RS champion spark plug challange series. I can't recall the name when C+C was there but will look it up in on of the programs I have from Mid Ohio. C+C won many races and the series with the 2.8 engines.

I also think but not sure but the USAC Miget series used the 2.8 in some Midgets for a short while but later were replace by the 4.3.

The reall engine of V6 racing was the 4.3 and mostly the 3.8 Buick. the saw the most use and development. The 2.8 saw very little and was never really saw much use as a race engine. Great road engine but never a great race engine. I am sure someone can find some rare or odd race car with a 2.8 but it was never a major factor outside the C+C team.

The SD 4 also was used in racing boats and the Daytona Dash series now that I remember.

[This message has been edited by hyperv6 (edited 03-16-2007).]

BTW, IIRC the Fiero's 2.8 was the only version to use the newly-designed "High Output" cam and heads, which were both used on the 3.4 when it was introduced for the Camaro/Firebird. One of the few bragging points of the 2.8, I guess.

quote Originally posted by FieroGT42: BTW, IIRC the Fiero's 2.8 was the only version to use the newly-designed "High Output" cam and heads, which were both used on the 3.4 when it was introduced for the Camaro/Firebird. One of the few bragging points of the 2.8, I guess.

The 2.8 HO Originally was brought out in the 1983 X-11 Citation. It used the same heads and cam. The Pontiac did use their own intake, exhaust manifolds and the computer was closed loop vs Chevys mass air.

The cam and heads also were available in GM Performance book with non production aluminum 2.8 block.

quote Originally posted by whadeduck: If I remember correctly, the IMSA Fieros used the 2.8. I believe some of the Pontiac Spices in the Camel Lights division used them too. My guess is that using the 2.5 as a base, to include the SD, would be too expensive and unreliable for racing as compared to the 2.8. Same as with our stock Fieros. If you want more power out of your four cylinder, you can modify it and get a certain horsepower out of it. But it's expensive and the motor will probably break quickly. Or you could start with the stock 2.8 with as much HP as you get out of a heavily modified four and have a better, more reliable platform to start with and get more HP out of it.

What also may confuse some people is the SD4 was able to be built as a 2.5L, a 2.7L, and a 3.0L engine. They had crankshafts for each displacement. 2.7L was the most popular size for the SD4. In IMSA racing, GTU class has to have an engine Under 3.0L and the GTO class was engine Over 3.0L. GTP Lights was 3.0L or less (popular with the SD4 and later with the QUAD4 engine) and the regular GTP was the V-8 cars.

Today the SD4 2.7L is the ARCA series standard engine size. But the SD4 isn't made by GM, Kansas Racing Products is licensed to build SD4's.

Also the SD4's were also used in Firebird and Grand Am race cars as well.

quote Originally posted by hyperv6: The 2.8 HO Originally was brought out in the 1983 X-11 Citation.

It was also used in the 1983 Firebird SE's. (had one.)

[This message has been edited by Oreif (edited 03-16-2007).]

At least one Fiero race car uses a 3.5L Buick V6 in a longitudinal layout with ITBs and DIS. The owner is from Aromas and races it occasionally at Laguna Seca.

Many Fiero's after they left the Pontiac Motorsports programs kept racing for years later. They have had different engine layouts and and changes made over the years and do not always have the orignal set up's in them.

The only stock body Factory car was the Digman Brothers Bob Earl driven GTO Fiero. It did not make the whole season with Pontiac's support since it race in 1988. The car survies in tact in Florida and has been seen on this site many times due to Red GT and his great photos.

The GTO car had a 4.3 Chevy with a Hewland Transaxle from the GTP cars. This Stock like bodied car had a lot of GTP parts under the skin. The cool part is when I saw it run it did use a stock leather GT steering wheel.









This GTO Fiero is 100% original from its last race and has not been restored.

All other GTU Fiero's were transverse engine layouts.

[This message has been edited by hyperv6 (edited 03-16-2007).]

quote Originally posted by hyperv6: The 2.8 HO Originally was brought out in the 1983 X-11 Citation. It used the same heads and cam. The Pontiac did use their own intake, exhaust manifolds and the computer was closed loop vs Chevys mass air. The cam and heads also were available in GM Performance book with non production aluminum 2.8 block.

The HO came out on 1981 as the Z code carb engine and was converted to MPFI in 85 using a mass in the Chevy and SD in the Fiero.

quote Originally posted by FieroGT42: BTW, IIRC the Fiero's 2.8 was the only version to use the newly-designed "High Output" cam and heads, which were both used on the 3.4 when it was introduced for the Camaro/Firebird. One of the few bragging points of the 2.8, I guess.

This is true...the L44 used in the Fiero was the only 2.8 to get the larger head and Cam. This is why I warn people who want to swap in a 3.1L from a minivan that it's a downgrade from the Fiero 2.8.

quote Originally posted by hyperv6: This GTO Fiero is 100% original from its last race and has not been restored.

That is such a gorgeous car. Always loved it!

quote Originally posted by TK: The HO came out on 1981 as the Z code carb engine and was converted to MPFI in 85 using a mass in the Chevy and SD in the Fiero.

I am doing this from memory and could not recall the carberated 2.8 HO but now you metion it I think I have a Motor Trend with the X-11 and all the parts that made it one form an earlier year. I know the MPFI did not make it till around Feb of 1985 since my dads Eurosport with the same engine had to wait till it was available mid year.

I never have seen the L44 Pontiac 2.8 called a SD? Where did GM ever call it a SD? My lit only show Pontiac as a 2.8 HO too.

Also note the L44 was the engine of choice in the Pontiac 6000 STE. But it was only available in the high option STE and not the SE.

quote Originally posted by hyperv6: The Chevy 2.8 HO had the same cam and head just a different intake and computer for the fuel.

What was the power output on the Chevy 2.8 HO? I'm betting that the L44 made more net power in the Fiero, if nothing else with the shorter exhaust.

quote Originally posted by hyperv6: I never have seen the L44 Pontiac 2.8 called a SD? Where did GM ever call it a SD? My lit only show Pontiac as a 2.8 HO too. Also note the L44 was the engine of choice in the Pontiac 6000 STE. But it was only available in the high option STE and not the SE.

SD is refering to speed density, the MPFI calibration in the computer.

quote Originally posted by FieroWannaBe: SD is refering to speed density, the MPFI calibration in the computer.

Sorry I did not understand Thanks!

[This message has been edited by hyperv6 (edited 03-17-2007).]

The original 660 engine was the 1980 X code engine.

In 1981 GM released the HO Z code engine in the X-11. It was rated 140 HP and 150 lb-ft depending on the docs you read. It had a red-line of 6500 RPM. It used the new bigger valve heads, higher compression pistons, higher lift cam and larger oil pump. It was carburated. It had the smaller diameter crank journals (63mm I believe). The exhaust was a Y pipe similar to the later Fiero version. The X-11 had true cold air induction via the cowl. That hood was real.

They still produced the base V6 using the smaller valves and lower compression pistons. I think it was rated 110 or 115 HP.

In 1982 they switched to the crossover style exhaust and dropped red-line to 6000 RPM. The engine was now available in the other cars (Omega, Phoenix, Skylark.) The crossover change was mainly due to the cradle change and moving the rack from the firewall to the cradle.

1983-1984 were the same.

In 1985 GM released the MPFI version of the engine in two forms: the LB6 and L44. Both are the same engines other than the manifolds, the upper plenum and accessory brackets (stuff needed to get the engine in the rear of the car). GM certified the engine with both the mass air flow system (using the 6870 ECM) and the speed density (using the 6869 ECM). If one had failed the tests they could switch to the other. Since both passed, they put them into production for field testing. Some early LB6 engines had the smaller crank journals (I've never seen one) but generallly the LB6 and L44 used the larger journal blocks (67mm).

The LB6 was rated 135HP and 160 lb-ft and the L44 was rated 140 HP and 170 lb-ft. In 88 I believe the L44 dropped to 135HP but they are all the same engine, same specs, etc. other than little things to get them into the car. The RWD version of the LB6 was the S engine and the FWD was the W engine. There is nothing really special about the Fiero V6.

In 1986 the Fiero switched to the 7170 ECM. It is the same hardware as the 6869 and 6870 other than the embedded code.

Again, there is nothing really unique about the Fiero engine other than the exhaust manifolds and while appearing to be something special, I think it was just a cheap way to get manifolds for the Fiero since no other car would need them. I don't know if the Beretta version used stainless manifolds. Maybe someone knows.

If you get a chance to drive an 81 X-11 do it. Wind that baby up! It will clear 7000 if you let it. The short runners of the cab intake made a huge difference in the upper end but it lacked the low end torque of the MPFI engine (which won't wind up like the carb). I owned three X-11s and one time. I still miss them.

[This message has been edited by TK (edited 03-17-2007).]

quote Originally posted by TK: Again, there is nothing really unique about the Fiero engine other than the exhaust manifolds and while appearing to be something special, I think it was just a cheap way to get manifolds for the Fiero since no other car would need them.

You casually toss out that there was nothing special about the L44, but it did make more power than any other GM push rod V6 of it's time. And I think it has the best exahust tone of any V6 ever to come out of GM.

I agree it made a little more power but not enough to make much differance. 5 HP-185 HP is nothing to write home about.

Pontiac claimed the Closed loop system was to make for better divablility which is true to a point. It also made it harder to modify the engine without messing the computer up. With the Chevy mass air system it would adjust better to any changes.

The intake is not really much different and was changed to cleat the deck vs the Chevy.

I do agree the Fiero Exhaust has a great sound. The stock muffler combind with the 60 degree engine have always made a great sound.

Keep in mind small differances in HP from year to year can be also just the way it was tested. The 85 and 88 Fiero showed 5 HP more but we all know it was no faster or better then the engines from 86-87.

The bottom line is Pontiac did a great job with sound and dressed the engine up better. But as power goes the 2.8 is not and never was a power house. Most smaller 4 cylinders are well over even the Fiero's power witha thrid less displacment in cheap 4 door sedans. So I would not sweat the 10 HP here or there. It was a good solid engine for it's time and not anything that will be on any all time top ten list and leave it at that.

quote Originally posted by hyperv6: The bottom line is Pontiac did a great job with sound and dressed the engine up better. But as power goes the 2.8 is not and never was a power house. Most smaller 4 cylinders are well over even the Fiero's power witha thrid less displacment in cheap 4 door sedans. So I would not sweat the 10 HP here or there. It was a good solid engine for it's time and not anything that will be on any all time top ten list and leave it at that.

I don't disagree with anything you said, but since he asked about the History, for it's time the L44 was up there with the best of the V6s. I can remember walking down the street in the 80s and I could tell when a 2.8L was approaching just from the sound.

True today, the measly 140 hp or so is nothing to write home about. Just about any grocery getter today will have more hp than that. But given what they had to work with, Pontiac delivered a pretty decent motor. Waaaaaaay better than the 2.5 in almost every way possible.

Agreed! In 1981 the HO engine was killer. The 660 series didn't become dated until the early 90s.

TK

guys, dont forget the aluminum 2.9 v6, not used in racing, but only cause it scared the corvettes.

quote Originally posted by jscott1: Just about any grocery getter today will have more hp than that. But given what they had to work with, Pontiac delivered a pretty decent motor.

x2
always when I tell people that I get 27mpg out of this old car they are just looking like wtf...

remember that todays grocery getters probably have more hp, but they are heavy! back in '88 a Opel Kadett with the 2.0L 16valve engine and 150hp reached the 60mph in just under 8 seconds. Today some even smaller cars with their ~180hp-200hp are slower.

also dont the newer high horse 4cylsput out less FT/LBS than the L44in a heaver car to