i have an 86 fiero gt with a 2.8 auto whats some cheap mods i can do to gain more power thanks

There isn't a lot to do to the 2.8 auto combo really. I have that combo myself. LOL
Start by a good tune-up, if you can weld remove the stock y-pipe and cut the big restriction out. A shift kit for the TH125 would help.
Other than that...turbo, nitrous, cam, port/polish or engine swap.

you mean cut the y out and run true duals?

https://www.fiero.nl/forum/F...HTML/097768.html#p23

And of course port the exhaust logs, you'll see when you get them off why.

You could also port the intake manifold.

Like what has been said, a good tune up is a good idea. Just go over everything, I'm sure you'll find something that could be replaced.

You aren't really cutting the Y-pipe out, search for DodgeRunners 3.4 build, it has pics.
The factory created the y-pipe so that it has a major restriction (to cut assembly cost I assume) It has a "wall" in the middle of the two pipes. Some say it is such a restriction that you gain like 5 rwhp.

quote Originally posted by IROCTAFIERO: ...if you can weld remove the stock y-pipe and cut the big restriction out.

quote Originally posted by 2.5fierose: you mean cut the y out and run true duals?

quote Originally posted by IROCTAFIERO: You aren't really cutting the Y-pipe out, search for DodgeRunners 3.4 build, it has pics.

IROCTAFIERO is referring to removing the restriction within the Fiero's Y-pipe, not removing the Fiero Y-pipe itself.

Shown below is Dodgerunner's "Before" versus "After" comparison of a sectioned Fiero Y-pipe that has been modified:

quote Originally posted by Dodgerunner: Well here is the before and after pic. While there is some restriction don't know how bad it really is but took it out like others have.

2.5fierose, this is the same photo in the link that bnevets27 provided you two posts above. It seems a bit of an "eye opener," doesnt it?

of all the things I did to my 2.8 to get "more power" - the single thing which did the most was:
switching to a manual trans

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1985 Fiero SE - Plain Red 3.1 V6 Coupe
Engle18Cam DIS 4.10-4spd 7730 WCF Long Tubes Borla
D.A.M.M. - Drunks Against Mad Mothers

Port those exhaust logs and Y pipe. Get the timing dead on - use quality tune up parts - AC Delco if you can. Remove the upper plenum and clean it - inside - take it to a machine shop and have it tanked if you can. Also give the TB a thorough cleaning. Service the cooling system - make sure it is not running too hot or too cold. The 2.8 likes to run in the 190 to 210 range.

thanks for the info on that i also heard that the in the factory intake manifold that it was very restrictive and limits the power what can i do to that or is this not true

It's true. Porting/polishing only helps a little. Username Francis T sells a bolt-on intake that is much better and is quality construction. However, it may not do much on a mostly stock 2.8. It really shines on modded 3.4s.

The bestest modification to a Fiero 2.8 V 6 is to modify the exhaust manifolds ,, the 2nd bestest is to open up the exhaust ,, 3rd bestest is to open the Y pipe ,,

The restriction in the exhaust limits all other modifications
Porting the manifolds is tedious and time consumming but worth it ,,Most exhaust manifold porting is not properly done
I am building a 86 gt 4 speed ,,into a 26,to,28 MPG around town Rat,,much of my work has not worked out,as I wish.. but I did the exhaust system in a detailed manner,, the difference in performance is amazing I wish i was not so cheap and had done a before and after dyno ,,I was more interested in Gas milage so the performance increase is frosting on the beets/ turnip greens delite ..

There is NO other modification that gives the benefits that exhaust manifold porting gives,,nothing else is close ,,you only have to eyeball the manifold the blockage is often 1/3 of the pipe ,,a wall that stops flow ,,
if you have to have a cat use a performance cat ,,I gained 15 horse power easily ,,but you will probably not do as thorough a job as I did ,, I run no cat and use a 26 inch cherry bomb (use a shorter model,,or a thrush.!!
because of possible broken bolts.. this can be a bear of a job ..


Any modifications you make (cam,s porting, fuel,compression) are strangled unless you open up the exhaust there is a WALL in the port.. use the search feature on this forum to research porting exhaust manifold,,I swear my complexion cleared up! and I lost weight,
and am now more handsome !!!
I am 67 years old and have done many port jobs ,,I have never seen the blockage the fiero V6 has.. You need to remove the ""WALL"" and also smooth out the port weld so the flange weld is the same diameter from front to back..I remove the inner metal that is difficult to reach,,do not worry about this Very difficult to remove

[This message has been edited by uhlanstan (edited 07-09-2009).]

Here is what an unported one looks like.. You can see the ring around the flange opening. Then on the main pipe they just cut a slot in the pipe and left the extra on both sides of the slot. On my 3.4 I ported the heads, logs and Y pipe as shown above. I just check my mpg over the last two weeks and am getting 26mpg around town. I normally get 36+ on the Hwy.

[This message has been edited by Dodgerunner (edited 07-09-2009).]

DodgeRunner, which transmission are you running? I have read your entire thread but it's been forever and I can't remember.

I have owned many Fieros over the years and all of them have been great but I never owned an auto till my 88.
and I must say it is the bigest turd I have ever owned. it runs great but the auto kills it my other 88 has a 5 speed and it is way more fun to drive.
you can make a 2.8 a good motor just by fixing all the factory shortcuts just like others have listed.
good luck.

THE OBSTRUCTION IN MY MANIFOLDS ,,was much worse than Dodgerunners photo,,but even the log in the photo shows the Wall that stops flow,, I have been an advocate of exhaust manifold modification,, I was actually surprised at the performance increase this made ,,even a bad port job will help,, you can generate higher gas milage than any of the new V6 cars,, you can not equal thier horse power ,,The porting increases horse power ,,gas milage ,makes the engine run smoother run cooler ,,more efficient makes it possible for modification like cams & internal engine mods to realize thier full potential,, The cost is your time and $100.00 at the most I include the cost of welding ..

www.fierofocus.com/articles...exhaustmanifold.html
the letter after the t may be wrong ,, this is on the northern illinois site a great article wish i had plagerized it.. ha ha
sorry I can not get my computer to print this properly

[This message has been edited by uhlanstan (edited 07-10-2009).]

IROCTAFIERO it still has the izzy 4sp in it. I have a 5sp Getrag I plan on swapping in within before the end of Aug. so I can take a trip to western CO. with it. Want to get the rpms down a bit if I can.

I have to agree about the Fiero Auto. I never take my 88 on the interstate since I hate the high rpms it runs. I also have a 4T60 to rebuild and swap into my 88.

There IS actually quite a lot that you can do for your Fiero.

The only thing is that you should consider at least is... after spending tons of money in parts, you'll end up with a car that's still slower than most grocery getter sedans.

We're in a strange time right now though... I would figure that today is a lot like 1968-1969 in terms of performance. I mean, the average daily driver puts out over 200 horsepower, which was CERTAINLY not common back in 1984. I assume this will change in a few years with the new emissions standards that will be pushed through... but it's just something to think about.


200hp is pretty much the reasonable limit you can expect to get from your Pontiac Fiero's 2.8 V6, and that would include probably rebuilding it into a 3.1 or 3.4 V6, as well as a new cam, portmatching all the intake pieces, larger throttle body, exhaust, higher flowing cat, blah blah...

The alternative of course is to go with a turbo-charger. At this point, it's probably one of the better routes to go, especially if you want to keep the Fiero looking relatively stock anyway. You just need to make sure the engine can handle it.


Anyway, some quick easy upgrades are:

1 - Synthetic oil and high-flow air filter
2 - Accel or MSD super coil (replaces stock one, no modification necessary)
3 - Remove water seperator, or get Rodney Dickman's "kit" that bypasses all that stuff, goes directly from the scoop to the bottom of the intake)
4 - Ported Exhaust Manifolds (6-8hp)
5 - Higher flowing catalytic converter from Rodney Dickman or the Fiero Store
6 - Port-Match the entire intake (biggest need is in the middle to lower intake)
7 - Crane Roller Rockers, 1.52:1 or 1.6:1
8 - H272 or 2030 Crane / CompCam
9 - Bored throttle body from Darrel Morse (does he still do them?)

That's pretty much it, I might be missing a few things, but that's pretty much what you can expect. There's also a really well constructed intake called the Truleo intake, but it's fairly pricey, and it's almost worth getting a Turbo at that point.

I would talk to Dennis Lagrua on here, as he knows that area pretty well...

------------------
Todd,
2006 Pontiac Solstice
2004 Volkswagen Beetle Convt. (Wife's)
2002 Ford Crown Victoria LX
1987 Pontiac Fiero SE / V6
1981 EZ-GO Xi875-A "Miami Dolphins" Medical Cart
1973 Volkswagen Type-2 Transporter
1973 Oldsmobile Cutlass Supreme 350

Here's a question kind of related to the OP. I have an 88 with auto/Duke. I agree that the auto is lacking. I have some experience with turbo 350's and 400's and have built a few with shift kits, manual valve bodies, hi stall converters, etc. Is there something we can do to help the TH125? Is there a shift kit and aftermarket torque converters available?

Another question is - what about putting in the 4T60 behind the Duke? Would there be any benefits to it?

I agree that the manual Fiero is way more fun than the auto. I had an 86 SE with the 4 spd and I loved it - until I wanted to run 80 down the Interstate. I have an 88 Formula with the 5 speed - great car although it does not feel as "sanppy" as the 4 spd. But, I really like driving the 88 Auto/Duke - especially in downtown traffic. I would just like the auto to shift harder.

Sorry for the mini hyjack - but maybe some auto trans mods may help!

Pat

quote Originally posted by katatak: Here's a question kind of related to the OP. I have an 88 with auto/Duke. I agree that the auto is lacking. I have some experience with turbo 350's and 400's and have built a few with shift kits, manual valve bodies, hi stall converters, etc. Is there something we can do to help the TH125? Is there a shift kit and aftermarket torque converters available? Another question is - what about putting in the 4T60 behind the Duke? Would there be any benefits to it? I agree that the manual Fiero is way more fun than the auto. I had an 86 SE with the 4 spd and I loved it - until I wanted to run 80 down the Interstate. I have an 88 Formula with the 5 speed - great car although it does not feel as "sanppy" as the 4 spd. But, I really like driving the 88 Auto/Duke - especially in downtown traffic. I would just like the auto to shift harder. Sorry for the mini hyjack - but maybe some auto trans mods may help! Pat

nope. the best "mod" is to remove & replace. even a newer 4speed automatic is an improvement - they are geared slightly better

Well if you want to install a shift kit into the Th125, it is supposed to help the shifts, not the mpg

quote Originally posted by katatak: ...what about putting in the 4T60...? Would there be any benefits to it?

The 4-speed automatic transmission that I first think of for a Fiero is the TH440 or the 4T60.

First gear in that transmission (2.921) is 3% numerically higher than in the stock TH125 transmission (2.840). The difference is quite small, but slighty favors the TH440/4T60 for acceleration.

Conversely, second gear in the TH440/4T60 (1.568) is 2% numerically lower than in the TH125 (1.600). The difference again is quite small, but marginally favors the TH125 for acceleration.

Both transmissions have the same third gear (1.000).

The bottom line here is that the differences between those two transmissions in the first three gears either are quite small (3% one way, 2% the other), or zero (1.000 transmission gear for both transmissions while in third gear).

The primary difference between the transmissions is that unlike the TH125, the TH440/4T60 has a fourth, "overdrive" gear ratio (0.705) which will considerably reduce engine RPMs while cruising at highway speeds, thus benefiting fuel economy, but by itself doing nothing for acceleration.

For 2.5fierose's 2.8L `86 GT with auto, I've a vague recolection that changing the chain sprockets theoretically might boost his car's acceleration, but unfortunately, I don't recall the specifics of how or even if those chain sprockets actually could be changed to accomplish that with his car.


If someone has those specifics, please chime in.