Basic Performance Improvement for 87 GT (Page 2/3)
Patrick AUG 20, 08:33 PM

quote
Originally posted by Spadesluck:

My advice would be to enjoy the car how it is. Fix what breaks as you go.
Once you start on the "upgrade" train you may find yourself never driving the car at all.




quote
Originally posted by pmbrunelle:

I wouldn't bother with taking out a perfectly good 2.8 L just to add another 0.6 L to it.
To me, increasing the displacement makes sense when your engine is broken, and then "while you're in there" you rebuild it with more displacement.



Words of wisdom!
Gryffindad AUG 20, 09:14 PM
I mean... I appreciate what you guys are saying but I'd like to have a bit more power than provided by the stock v6 and it seems like performance options on the 2.8 is extremely limited without investing more than it's worth.
Mike in Sydney AUG 20, 10:05 PM
Gryffindad, you’ve got a perfect “iron-triangle” situation on your hands. As the adage goes, your options are fast, cheap, reliable. Pick any two. You can have it fast & cheap but it won’t be reliable. You can have it cheap & reliable but it won’t be fast. You can have it reliable & fast but it won’t be cheap.

You can pull close to 200hp out of a ’93-’95 3.4L engine if you do a performance build on it. It won’t be cheap but if I was installing a 3.4L in one of my GT’s, I’d be looking at doing that. You can still find used Camabird engines in the salvage yards but they’re between 25 and 27 years old so a rebuild is a good idea. For performance, you’d need a cam, roller rockers, porting & polishing, better exhaust, bigger injectors, etc. You can get a long-block rebuild from Jegs but you’d be looking at 150-160hp but it would have a warranty.

My suggestion: If it ain’t broke, don’t fix it. Stick with the 2.8 until it breaks then build for power when you have to. The downside is that may be a long time because the 2.8’s seem to be pretty reliable if they’re maintained.

Good luck and welcome to the addiction.

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Mike in Sydney

MarkS AUG 21, 09:22 AM
This is a great thread because there are so many new faces buying Fieros in it! Good luck with the new obsession! If sticking with the V6 2.8 to 3.4, intake mods will be needed to get the most out of those engines if you keep to original induction set up. I've gone round & round with this myself regarding the 60 deg V6. If common wisdom is to rebuild any engine prior to mods, then there is a mid road option of a 3.1 crank & pistons in the original 2.8 engine. Punch it out some and you get close to 3.2. Is it worth it? Dunno, if sticking with the original 2.8 then I'd say so. Just my $.02.
sourmash AUG 21, 09:45 AM
It's good to know the options, but if you're doing a replacement engine why wouldn't you go with the larger displacement 3.4 instead of spending the same machine shop money on the 2.8?

Next easiest swap than the 3.4 is what, the 4.9 or 4.5 Cadillac? There's your 200 hp.
Gryffindad AUG 21, 01:55 PM
Mike, I think there's some confusion because I never said cheap, I said cost effective. For example if the cost to get the 2.8 to the same performance as a 3.4 is the same cost as swapping in a 3.4 that doesn't seem cost effective to me where the 3.4 would still have additional improvement opportunities and the 2.8 wouldn't.

Having said that I might do some very minor things to the 2.6 while working on general maintenance and getting the car painted. K&N Air Filter, 1.6 roller tip rockers, etc.

Would still love some feedback on these:
- Should I just assume that the motor mounts need replaced?
- Are the suspension kits from Fiero Store worth getting? https://www.fierostore.com/...rowse.aspx?d=331&p=1
- Are there any resources in the DFW area? I've read some bad things about fastfiero on here
- Does anyone know the best place to get some original wheels?
fierofool AUG 21, 05:26 PM

quote
Originally posted by MarkS:

This is a great thread because there are so many new faces buying Fieros in it! Good luck with the new obsession! If sticking with the V6 2.8 to 3.4, intake mods will be needed to get the most out of those engines if you keep to original induction set up. I've gone round & round with this myself regarding the 60 deg V6. If common wisdom is to rebuild any engine prior to mods, then there is a mid road option of a 3.1 crank & pistons in the original 2.8 engine. Punch it out some and you get close to 3.2. Is it worth it? Dunno, if sticking with the original 2.8 then I'd say so. Just my $.02.



Going to a 3.1 will net you ZERO hp gain. I just replaced a blown 2.8 with a 3.1 and in trying to determine what injectors it required, I found that it only produces 140 hp. Just like the 2.8. To get the 2.8 or 3.1 up to the 3.4 ratings of 160 hp would cost more than just dropping in a 3.4.

In the meantime, if roller rockers and cam are upgraded in the current 2.8, those mods can be transferred to a later 3.4 install.

theogre AUG 21, 06:43 PM
Before you try anything above and more...
First check when you "floor" the gas pedal the engine end of cable makes TB to reach WOT.

A lot of old car's can't do that and worse w/ Fiero w/ long cable, ~ 3x length vs nearly all others, and worn pedal parts.

see my cave throttle cable

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Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave

RayOtton AUG 22, 08:28 AM
We've had this conversation before and it hasn't gone well but I will repost my 2.8 mods and the results because you asked.

To start -

I have a flat, straight, SAFE spot near my rural home where I can do some drag testing. It's about 3/4 of a mile long with a fire hydrant at the 1/8 mile mark as measured by my GPS. Of course it's not an actual drag strip but I can use it to compare engine mods and also from car to car for my own edification. Relative vs absolute, if you will.

For instance I had a Chevy Tracker that barely hit 60MPH at the 1/8 mile mark, an '89 Mustang 5.0 that hit 88 MPH, an '06 Civic that hits 77MPH and an 06' Lincoln LS that reached 94 MPH over that same distance.

The Formula with 45K miles and and automatic hit 67 MPH when I first brought it home.

Then I started a gradual HP upgrade process based on info from right here on Pennock's.

All of these runs were made at least three times with 1/2 tank of 93 octane fuel, power braked to 1800 RPM and auto shifts.

Bumped timing to 12 degrees - 67MPH
Underdrive pully - 67 MPH
Ported exhaust - 69 MPH
Ported UIM and throttle body - 71 MPH
Low restriction cat - 71 MPH
80 lb weight reduction - 72 MPH
Streetfire coil - 72MPH
Hypertech chip - 73 MPH
1.6 rockers. - 78 MPH

At this point I tried manually shifting because it felt like the automatic was leaving something on the table because it shifts at about 4700 RPMs. I shifted manually at 5500 RPM. (I felt there was more room to run but it is a 30 year old car).

That's when I hit 80 MPH.

The rockers made a huge difference, I assume because they took advantage of all the other mods. And if this means anything to the engineering guys, I think there was some bottom end degradation as per the butt dyno. Which was more than made up for by a big increase in the mid and upper ranges.

If I were to do it all over again I'd leave out the under drive pulleys. They were a PITA to do in the garage and they offered no gains.

All told I spent about $800 and a ton of hours on this incremental project.

I don't know the HP gains but they are significant enough that I've given up all thoughts of swapping engines. I didn't want a Corvette killer, I wanted a peppy sports car and that's what I've got now.

[This message has been edited by RayOtton (edited 08-22-2020).]

Dennis LaGrua AUG 22, 02:47 PM
A fast easy and inexpensive engine swap that would get you to 200HP and 275 ft lbs of torque is the Cadillac 4.9L engine.

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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "