Somebody sent me this and I was wondering how true it is. I know that the upper and lower intake manifolds could use some porting but I never heard of any detuning of the Fiero's hp for regulations.

"Another single performance gain I have heard of is to
drill out the fuel injector manifold holes to a larger diameter to allow a
larger spray cone of fuel into the intake. This allows for a better
atomization of fuel and air going into the cylinders, thus producing more
power and better response. This info comes from a forum where one of the
original Fiero design engineers explains that in order for GM to comply with
federal laws of the time, the 2.8L was "detuned" to the allowed maximum HP
of 140 due to the weight of the Fiero. The restricted injection ports were
the easiest and cheapest way to arrive at this figure. According to my
sources in Phoenix, the "Big Fiero Parts Book" available from PISA corp.
also mentions this in the engine rebuilding section."

i suppose that could be true but how much HP could this thing make if it was un-detuned.

Sounds like total urban legend.

1. It's easier to detune an engine with a cam shaft or ariflow restriction.

2. Restricting fuel flow after the injector would just result in poor driveability due poor atomization and puddling in the intake.

3. A 5.0L "High Output" Mustang made 153hp in 1983, how much more power do you expect out of a 2.8L V-6?

4. Puddles of fuel in the intake would adversely affect emmisions, especially unburned hydrocarbons.

-Vinny

Is there any porting I can do my self on the intake now that I have a chance?

The article you are referring to mentions that the spray pattern is interrupted by the casting. You can get a better spray pattern by doing a little grinding/polishing in there. I have the same book from a couple of years back and remember reading the article. You might get some gains but it is only worth it if you are looking to get the last bit of horse power out of your engine. You would be better of getting an extrude honed intake and getting the throttle body and plenum intake bored out. Remember that the engine is basically an air pump. The more air you can move in and out the more power you can make.

Off topic a bit, but in 1969 Pontiac used the same 400 engine in the Firebird and the GTO. The GTO was rated at 15 HP more than the Firebird. The way they did it was to install a screw so that the carb secondary throttle plates would not open all the way.

All of my Firebirds ran lots better when they left my shop......LOL.

Phil

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87 FIERO GT 2.8 5spd
0-60 in 6.8 seconds!
If you found my advice helpful, please take the time to give me a positive rating. Thanks

quote Originally posted by connecticutFIERO: Somebody sent me this and I was wondering how true it is. I know that the upper and lower intake manifolds could use some porting but I never heard of any detuning of the Fiero's hp for regulations. "Another single performance gain I have heard of is to drill out the fuel injector manifold holes to a larger diameter to allow a larger spray cone of fuel into the intake. This allows for a better atomization of fuel and air going into the cylinders, thus producing more power and better response. This info comes from a forum where one of the original Fiero design engineers explains that in order for GM to comply with federal laws of the time, the 2.8L was "detuned" to the allowed maximum HP of 140 due to the weight of the Fiero. The restricted injection ports were the easiest and cheapest way to arrive at this figure. According to my sources in Phoenix, the "Big Fiero Parts Book" available from PISA corp. also mentions this in the engine rebuilding section."

LOL! Somebody's talking about something they have no clue about, that's for sure. There are no federal regulations on power output. That's just balony. There were lots of cars that put out more than 140hp back then, just like now, regardless of weight. The only regulations that affect engine performance are emissions laws, and those only serve to increase effiency and power as evidenced by how much clean and reliable power cars have now compared to then. And, regarding the injector hole thing, that's pure horsepucky. The injectors spray against the backside of the closed intake valve, where the fuel is evaporated by the heat of the valve and engine. When the valve opens it sucks in a nicely evaporated charge of fuel and air.

Again, pure horsehockey.

JazzMan

quote Originally posted by JazzMan: LOL! Somebody's talking about something they have no clue about, that's for sure. There are no federal regulations on power output...

Check that again! Federal law will not allow 8:1 (or 18:1, too tired to remember) Power to weight ratio for it to be street ligel! That's what nissan Skyline's were not imported. When they were "gray cared" they had to be de-tunned to be ligel! Check that agian man !

Damn I LOVE being right

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www.freewebs.com/fierogti

<>{RazorWing}<>

quote Originally posted by Razor_Wing: Check that again! Federal law will not allow 8:1 (or 18:1, too tired to remember) Power to weight ratio for it to be street ligel! That's what nissan Skyline's were not imported. When they were "gray cared" they had to be de-tunned to be ligel! Check that agian man ! Damn I LOVE being right

8:1 Power to weight

8 Power
1 Weight

3000 lbs = 24,000 HP

I think you mean 1:8 P/W man

3000/8 = 375 HP maximum

Ahh, much better

Damn, I love being right!

My intake manifold has some pretty big injector holes in it already. They are 1/2" diameter.

quote Originally posted by Razor_Wing: Check that again! Federal law will not allow 8:1 (or 18:1, too tired to remember) Power to weight ratio for it to be street ligel! That's what nissan Skyline's were not imported. When they were "gray cared" they had to be de-tunned to be ligel! Check that agian man ! Damn I LOVE being right

Provide a link. So far you're the only one saying this, and it seems that you have direct knowledge of the law and I don't have time to spend the rest of my life digging for it.

The Skyline was probably not imported because Nissan didn't want to spend the money to get it legal here for such a low-volume car.

Again, I call on any power to weight law.

BTW, Ferrari F50, power to weight ratio 5.3:1; McLaren F1, 4.5:1, etc. See more at http://members.fortunecity.com/carstats/ .

No link, no proof...

JazzMan

[This message has been edited by JazzMan (edited 10-30-2003).]

im checking other place and ive found a few things

-From what I know talking with Motorex directly, there are quite a few, but minor if you will upgrades and addons (as they put it) that need to be done before the car can be reg'ed and plated.

Things such as side intrusion beams in the doors, and rear crash protection. Shawn would not disclose everything for obvious reasons but lets say that in parts and labour you looking at an additional 8,000 - 12,000 US dollars. You have to remember the local market that congress and the Dept of Transportation is protecting, not to mention what is required by law for safty equipment in the states.

-according to motorex

Q. What modifications do you perform in order for the GT-R to meet US regulations ?

A. In order to protect our business interests, research and developmentcosts, the answer to this question is confidential. Some of the basic items that are changed are things such as US emissions, speedometer , crash structure , lighting , US VIN , warning , and information labels.

from what i have found the power thing is bs in regards to the skyline.
they wont import b/c the reasons stated above

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quote Originally posted by Razor_Wing: Check that again! Federal law will not allow 8:1 (or 18:1, too tired to remember) Power to weight ratio for it to be street ligel! That's what nissan Skyline's were not imported. When they were "gray cared" they had to be de-tunned to be ligel! Check that agian man ;)! Damn I LOVE being right :D :D :D :D

Um...love being right? I, too, am calling BS. We have a gas guzzler tax, but I've never heard of such WEIGHT:POWER limitation. We have crash safety standards, lighting laws, and emissions standards that make importing certain cars infeasible. As has already been pointed out, you can get cars imported with FAR less weight :power than a Skyline.

If it was 18:1, about half of the sports cars of today would be illegal with just the base engine...hell, almost a third of the cars on the road. If it was 8:1, there are still plenty of imported cars that wouldn't be here.

Not only should you check your facts, but you should also check your spelling.

Bryce
88 GT
*edit:damn auto-smilies got me again

[This message has been edited by Nashco (edited 10-31-2003).]

quote Originally posted by Razor_Wing: Check that again! Federal law will not allow 8:1 (or 18:1, too tired to remember) Power to weight ratio for it to be street ligel! That's what nissan Skyline's were not imported. When they were "gray cared" they had to be de-tunned to be ligel! Check that agian man ! Damn I LOVE being right

What the hell are you talking about? I sure hope this is a joke because it's the most ridiculous thing I've ever heard.

Put down the bong and step back. Go to bed and sleep it off.

Just for sanity check...

ZO6 Corvette: 3115/405 = 7.69
New Viper: 3300/500 = 6.6

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'87 Fiero GT: Northstar, Getrag, TGP wheels, rear sway bar, rod end links, bushings, etc.
'90 Pontiac 6000 SE AWD: Leaking ABS unit fixed, load levelling rear suspension fixed, still slow

Just my .02, if I remember correctly, Japan had/has some sort of power restriction (~300ish) on their cars which is why the 3000GT, Supras, RX-7s, 300ZX, Skylines all had about the same power in top trim.

Yea motorex wont disclose what they do because that is insanely overpriced for the BS they so said do. The new regulations are so screwed up that we get trash for new cars that don't last.

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quote Originally posted by JazzMan: LOL! Somebody's talking about something they have no clue about, that's for sure. There are no federal regulations on power output. That's just balony. There were lots of cars that put out more than 140hp back then, just like now, regardless of weight. The only regulations that affect engine performance are emissions laws, and those only serve to increase effiency and power as evidenced by how much clean and reliable power cars have now compared to then. And, regarding the injector hole thing, that's pure horsepucky. The injectors spray against the backside of the closed intake valve, where the fuel is evaporated by the heat of the valve and engine. When the valve opens it sucks in a nicely evaporated charge of fuel and air. Again, pure horsehockey. JazzMan

time to add my two cents worth...

(Not picking on you here Jazzman..just trying to keep my post in perspective so that the "real" BS flag wavers will not give me a negative rating... )

..first let me say that all you BS freaks are way off base again.. You are just too ready to start waving your flags.. and spouting your retoric (read: just talking to hear yourselves talk..)

The fiero was ALWAYS DETUNED FROM THE FACTORY.. this was a corporate
edict due to C.A.F.E requirements.
Fact # one.
Take the HP to weight ratios from 1984 standards. The 84 corvette weighed more than the 84 Fiero, but it only produced 205 HP (Crossfire injection). No way could the " Fiero economy car" have a lower hp to weight ratio than the "Vette". Remember that there were turbo Fiero prototypes and V8 Fiero prototypes. ..All out performing the Vette, year for year.
Fact # two.
We already know that the fiero intake is restrictive at higher Rpm’s. But porting the intake system is always a tradeoff. (the lower rpm flows (under 2000 rpm)are compromised so that higher rpm flows will flow better...).AFTER you increase the airflow, the NEXT step is to increase the "Fuel Supply" and try to get a better spray pattern in the process.
Now due to the fact that the Fiero was always an "economy car" corporate policy was to strive for maximum fuel economy numbers rather than peak HP output. Also remember that at this time in history if the manufacturer could not meet the C.A.F.E. goal, they were forced to suspend sales on the performance cars until they again met the C.A.F.E. number.
Put yourself in the corporate decision making loop. Would you want maximum fuel
economy out of the Fiero.. or want to add HP (decreasing the economy factor and then
having to suspend the sales of the V8 F Bodies and Corvettes (and the big engine 4WD
trucks that were only getting 10 miles to the gallon, too) sooner.
The stock 2.8 Fiero was set up for maximum fuel economy.. not maximum power. Which was just another corporate compromise.. The public wanted a fiero with more power than the Duke was producing. So the V6 that was chosen was the "economy V6 and not the 3.8 the 4.3. or the 4.5/4.9 V8. Also remember that the Fiero intake system was designed from the start for fuel economy Not Power. (and everyone knows that even now, HP can be increased by modifying this part of the intake system.)
Therefore the Fiero was "detuned" from the start, and never was going to be a factory high HP sports car, as it would not then fit into the bigger picture.

.. So instead of just waving your BS flags..LOOK at the bigger picture.

But everyone should realize that the 60 degree V6 is self limiting anyway. But if you want more power from this engine, the best bang for the buck is Nitrous or forced induction rather than messing with the intake system flow. Even better is swapping in a smog compliant newer motor (Read: 3800 series II SC engine) that is producing more power and getting better fuel economy.

C.A.F.E. = federal regulations

[This message has been edited by SanBerdueFiero (edited 10-31-2003).]

I think the power to weight issue was a Insurance issue back in the late 60's to early 70's that targeted the muscle cars of that time.

[This message has been edited by Phoenix (edited 10-31-2003).]

Its actually 280HP, it was a gentilmens agreement in Japan not to produce cars that have more than that. I am not quite sure if its still in effect or not.

James Z

quote Originally posted by virii01: Just my .02, if I remember correctly, Japan had/has some sort of power restriction (~300ish) on their cars which is why the 3000GT, Supras, RX-7s, 300ZX, Skylines all had about the same power in top trim.

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quote Originally posted by SplineZ: Its actually 280HP, it was a gentilmens agreement in Japan not to produce cars that have more than that. I am not quite sure if its still in effect or not. James Z

yea it's still in effect, as for the Nissan R34 (their latest skyline model) is still rated at 280 hp...but with some tuning and money, you can make that 280 hp into 800+

-Coop

I used to have a 91' 300ZX soI did alot of research on the nissans and was a member of a Nissan/Datsun club. The only reason the Skyline was not imported was the fact that the US already had one nissan super car the 300ZX twin turbo. These cars had 300hp and for about $2000 more could get a cool 200hp more. They were every bit the performer the skyline was maybe more. I don't know about regulations but it (Fiero) may not have passed polution tests until it was tuned down.

Actually CAFE stands for Corporate Average Fuel Economy or the average miles per gallon all of the company's models get.

quote Originally posted by SanBerdueFiero: The fiero was ALWAYS DETUNED FROM THE FACTORY.. this was a corporate edict due to C.A.F.E requirements. Fact # one. Take the HP to weight ratios from 1984 standards. The 84 corvette weighed more than the 84 Fiero, but it only produced 205 HP (Crossfire injection). No way could the " Fiero economy car" have a lower hp to weight ratio than the "Vette". Remember that there were turbo Fiero prototypes and V8 Fiero prototypes. ..All out performing the Vette, year for year.

The Fiero was not "detuned" from the factory. It was tuned for emission compliance with the best perfomance of the 60* V-6. If it was "detuned" why is it the Fiero 2.8L was the highest horsepower 2.8L GM made? The S-10/S-15 trucks/SUV's (Which at the time had LESS emission requirements) Only had 120hp. The Pontiac 6000 and Chevy Celebrity weighed more than a Fiero and the 6000 did have an AWD version only had 130hp. The Cavalier Z-24 only had 125hp. Even the F-body cars only had 130hp.

There are no weight/HP "standards". In the 80's is when emission standards started to tighten. Hence the technology of the time prevented high horsepower V-8's from being emission compliant. As advances grew in controlling emissions, then the horsepower of the engines increased.

quote Originally posted by SanBerdueFiero: Fact # two. We already know that the fiero intake is restrictive at higher Rpm’s. But porting the intake system is always a tradeoff. (the lower rpm flows (under 2000 rpm)are compromised so that higher rpm flows will flow better...).AFTER you increase the airflow, the NEXT step is to increase the "Fuel Supply" and try to get a better spray pattern in the process.

Again this is incorrect. The Fiero intake is one of the best flowing intakes for the STOCK 2.8L. The restriction comes into effect when the engine displacement is increased or the engine is modified. "Lower RPM flows"??? What is that? Do you think that porting the intake decreases air flow during low RPM's??? The fuel is regulated by the MAP sensor. So the increased air flow of porting is already compensated.
As for spray pattern, The Fiero uses pintle type injectors. The later disc type injectors have a better spray pattern. Again this is one of those things where you need to put the technology of the time in perspective. Just because engines today have good flow and good spray patterns does not mean that they knew about it 18 years ago.

quote Originally posted by SanBerdueFiero: Now due to the fact that the Fiero was always an "economy car" corporate policy was to strive for maximum fuel economy numbers rather than peak HP output. Also remember that at this time in history if the manufacturer could not meet the C.A.F.E. goal, they were forced to suspend sales on the performance cars until they again met the C.A.F.E. number. Put yourself in the corporate decision making loop. Would you want maximum fuel economy out of the Fiero.. or want to add HP (decreasing the economy factor and then having to suspend the sales of the V8 F Bodies and Corvettes (and the big engine 4WD trucks that were only getting 10 miles to the gallon, too) sooner.

Fuel economy was not the driving force in engine design. Emission output was what they had to design for. If fuel economy was such a high priority, why did they ever go with the V-6? They would have stayed with the 4-cyl. In order to meet C.A.F.E. standards, you needed to have a certain number of cars getting a certain level of gas mileage. There were plenty of cars in GM's line-up that allowed them to meet the C.A.F.E. levels for gas mileage. It was the EPA emission levels that dictated the engine designs. The Fiero was originally designed as a "Sporty Economy Car" and evolved into a "Sporty 2-seater Car" (NOTE: I said sporty car, NOT a high horsepower sports car)

quote Originally posted by SanBerdueFiero: The stock 2.8 Fiero was set up for maximum fuel economy. not maximum power. Which was just another corporate compromise.. The public wanted a fiero with more power than the Duke was producing. So the V6 that was chosen was the "economy V6 and not the 3.8 the 4.3. or the 4.5/4.9 V8. Also remember that the Fiero intake system was designed from the start for fuel economy Not Power. (and everyone knows that even now, HP can be increased by modifying this part of the intake system.)

See my first paragraph about the Fiero 2.8L power. The 3.8L and the 4.3L were NOT FWD engines back then. There is no such thing as a 3.8L FWD, when they made the FWD version, they were called 3800's. They didn't come out until the end of the 80's which by that time the Fiero's demise was already in place. (Actually there is no FWD 4.3L even today.) The 2.8L was the the most reliable V-6 FWD engine availible and the Fiero had the highest horsepower. Buick had a 3.0L FWD V-6 for 2 years, but the reliability of the engines was poor and the engine was dropped. The Cadillac engines were only for Cadillac's use. No other GM vehicle used the 4.5/4.9 V-8's.

quote Originally posted by SanBerdueFiero: But everyone should realize that the 60 degree V6 is self limiting anyway. But if you want more power from this engine, the best bang for the buck is Nitrous or forced induction rather than messing with the intake system flow. Even better is swapping in a smog compliant newer motor (Read: 3800 series II SC engine) that is producing more power and getting better fuel economy.

For someone who keeps being a stickler for Emission compliance, You keep pushing the NOS. In case you forgot, NOS is not allowed to be used on the street in most states, and does not meet emission compliance.
As for the 60* V-6 being "self-limiting", It's not the engine that is limiting, it's your view and lack of understanding of the engine.

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Happiness isn't around the corner...
Happiness IS the corner.

[This message has been edited by Oreif (edited 10-31-2003).]

flame on. lol

quote Originally posted by Oreif: *.*

What he said.

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Donny
95 Z28 M6; Free mods, bolt-ons, 13.3@102 1.9 60' on DRs (Pic)
91 AccordA4; Stock. 140K miles. Runs like new.
86 Fiero SE M4; Not even mine anymore but I'm still stuck working on it ;) 3.4L, bolt-ons
86 Fiero SE M4; Restore and heads/cam 3.4L in progress.

No 3.8L FWD? Don't tell GM that. The A body's had the 3.8L Port engine in 85. My 86 Ciera had a 3.8L port engine (not 3800 mind you).

Well, at least GM called them 3.8L in the literature and manuals....

The B,C and 3 engines were all called 3.8L. Maybe GM called them 3800's somewhere from 85-87.

Otherwise I agree with your comments, well most.

[This message has been edited by TK (edited 10-31-2003).]

quote Originally posted by TK: No 3.8L FWD? Don't tell GM that. The A body's had the 3.8L Port engine in 85. My 86 Ciera had a 3.8L port engine (not 3800 mind you). Well, at least GM called them 3.8L in the literature and manuals.... The B,C and 3 engines were all called 3.8L. Maybe GM called them 3800's somewhere from 85-87. Otherwise I agree with your comments, well most. [This message has been edited by TK (edited 10-31-2003).]

"A" bodies were the Celebrity, 6000, Cutlass and Cierra, and the Century. These had 2.5L Duke's as base engine and 2.8L for the V-6. If yours had a 3.8L it must have been a Cierra only option because I know for a fact the rest only got 2.8L engines for the biggest engine. Even the top of the line 6000STE had a 2.8L with it's AWD version.

Doing a quick search via Google and looking thru Edmunds, None of the "A" bodies list a 3.8L for the engine. They only show the 2.5L and the 2.8L.

They started with the 3800 designation in the Bonneville size cars in 87/88 when they went to FWD.

Buick Century and the Olds Ciera both got the 3.8L port engine. The 2.8L was available for one or two years (with manuals trans too! 6000 STE manual anyone?) in at least the Ciera but I don't know about the Century. The Celebrity and 6000 never had the 3.8L engine available. All had the 2.5L. There was one year of 3.0L MPFI in the Century and Ciera. We'll ignore the 4.3L diesel.

The engine I removed from my 86 Ciera GT was a 3.8L port engine code 3, not a 3800. I replaced it with a 3800SC code 1. Again, none of of labels, manuals, logos said 3800, rather 3.8L. Again, it might be semantics.

For production cars, anyone can argue they are "detuned" from the factory. They certainly are for emissions. If emissions aren't a concern and you can fine tune each engine, you can certainly get more HP. Even the 3.4L DOHC and SC engines are dynamically detuned for shifts. The turbo Regals are detuned since there is tons of unused boost. But in terms of mass production, I don't think the 2.8L is all that detuned. 140HP from 173 cu.in. in 1981-88 isn't half bad with some nice torque to boot. Then considering the modest increase in HP people get after throwing a lot of money at a 2.8L (rockers, porting, etc.), I think the production 2.8L is near the top of it's capabilities.

TK

[This message has been edited by TK (edited 10-31-2003).]