I'm in the middle of buying a 3.4 from a 95 Camaro. $450 Canadian, 3 hour drive there and 3 back. Snow is already on the ground, and it's getting colder so I won't be pulling the 2.8 from the Fiero until spring.
TONS of info on the actual swap which is great. I think I'll be able to handle it. But a few questions.
What kind of things should I be replacing/checking while the 3.4 is in the garage? I don't want to do a full out performance rebuild of the engine, I just want to make sure it will be running well and that I don't have to pull it back out after a week of spirited test driving.
And is there any decent tunes for a stock 3.4 that use the 7730 ECM? I actually have an 8262 which is apparently just an updated version that works exactly the same.
Finally, stock Fiero is 140ish right? And the 3.4 is 160. I read that some people have gotten near 20hp from upgrading the 2.8 to the 7730 with a knock sensor, because it let's the engine push itself further because it can actually determine when it's knocking. So what would the 3.4 get with a 7730 ecm? The 3.4 already has a knock sensor, and is supposed to run DIS. So is the only real benefit just response time and mpg with a proper tune? Or could you gain some hp too similar to the 2.8?
I really don't think anyone's getting 160 from a stock 2.8 just by upgrading to the 7730. Maybe just a few more horse, but that's all. The best benefit of that is just better response time due to faster input from the sensors.
A minor thing until you forget to do it is to remove the pipe plug from the passenger side of the 3.4 head, just to the top left of the #5 cylinder and install it on the front of the other head just above the #2 cylinder. This is your temp gauge sending unit. On the 3.4 it's on the exact opposite corner of the engine from the Fiero position. Keeps from having to modify engine harnesses, and makes replacing a failed sending unit much, much easier. Don't leave the old Camaro sending unit in the head. Be sure to move the pipe plug to that location. Gauge sending units can fail and cause a coolant leak. Rarely, but they can leak.
I have a stock F-body 3.4 in my 85 SE V6 Fiero...Using the stock computer & controls......I get approx 160 hp (vs stock 2.8 140 hp) but the torque goes up from 170 to 200........The big difference is that all of this takes place approx' 1000 rpm lower in the power band.......Kind of like installing shorter gearing......The top end is not spectacular, but 0-30 is psychotic! You have over 100 hp by 2600 rpm, and will stay over 100 hp until 5000....Thru the gears, that is half of your total rpm....You rarely have to shift on a tight winding road.....
The stock computer does not work the F-body injectors...I have heard that 88 Fiero computers will work them...and I suspect that your 7730 will do ok....My low throttle drivability is poor....the throttle is a bit twitchy. I'm in CA so I can't switch to the 7730 computer.....
The mileage on the engine would be critical to what you do to it for longevity......(My engine had 30,000 F-body miles before the swap......Still going strong after 60,000 additional hard driving miles......)
The stock computer does not work the F-body injectors...I have heard that 88 Fiero computers will work them...and I suspect that your 7730 will do ok....My low throttle drivability is poor....the throttle is a bit twitchy. I'm in CA so I can't switch to the 7730 computer.....
The mileage on the engine would be critical to what you do to it for longevity......(My engine had 30,000 F-body miles before the swap......Still going strong after 60,000 additional hard driving miles......)
I've done two 3.4L pushrod engine swaps (93-95 F body) and both used the stock Fiero V6 ECM's. Both worked but to optimize running, slight adjustments to the program fueling tables were required. The 7730 is no doubt a better ECM but with a small program change to a feature flag and the addition of an ESC module; a knock sensor can be used with the 85 Fiero V6 ECM. (not 86-88) While a reasonable mileage 3.4L P/R engine swap will pull well.; you will notice the difference but it won't be dramatic.
------------------ " 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 "
I'm using the same PCM that came with that motor in a 3100 engine that I swapped the bottom end out of from a 3400. Works silky smooth. They used the same PCM in the 1996 Grand Am 3100's as the 3.4 … You'd have to have the intake reversed though so that the throttle body point to the Fiero side but You'll have a smooth running engine... Whomever did the swap put the PCM in the trunk but if you don't mind playing with wires I'm sure you could mount it in the stock location.
I used a 3.4 in an old British car and because I am in Canada and didn't want to mail the 1994 PCM back and forth for tuning, I used a late 1988 Beretta chipped ECM, which works just fine.
I ditched the SFI feature which gives you sequential injector firing, but only up to a certain rpm, after which it reverts to batch firing, because the earlier ECM doesn't support it.
You will want to keep the knock sensor and DIS system.
Another question for you guys. Who here has installed a 3.4, with the aluminum heads and intake of a 3400? Been reading a lot and apparently it's waaaay better flowing, but I'm not sure if any fiero people have done that kind of work on a 3.4.
Another question for you guys. Who here has installed a 3.4, with the aluminum heads and intake of a 3400? Been reading a lot and apparently it's waaaay better flowing, but I'm not sure if any fiero people have done that kind of work on a 3.4.
If you want to do all that, you may as well start with a complete 3400 engine. Better oiling, roller camshaft/lifters, starter on correct side for Fiero etc.
The later aluminum heads are way better; Bigger valves and ports, the valves are canted so they move away from the cylinder walls.....One big problem with adding them to the Fiero; The intake ports do not even come close to lining up with the Fiero intake....I wish someone would make a lower intake that would match those ports to the Fiero upper plenum.......That would be great!
If you want to do all that, you may as well start with a complete 3400 engine. Better oiling, roller camshaft/lifters, starter on correct side for Fiero etc.
Isn't it overall more work going that route though? I have 2 venture vans with the 3400 now that I think about it, not sure if those are also aluminum heads though.
I wish someone would make a lower intake that would match those ports to the Fiero upper plenum.
But then you'd still be stuck with that major flow restriction in the neck of the Fiero upper plenum (unless it was modified). Would be easier (and flow a whole lot better) to just use the 3400 upper plenum...
...and have the Fiero logo engraved onto the top (if that's what you're afraid of losing).
[This message has been edited by Patrick (edited 10-20-2018).]
...and have the Fiero logo engraved onto the top (if that's what you're afraid of losing).
You can have any lettering removed (sanders work well) and have the plenum recut with a computer operated milling machine to put the Fiero on it (or use the sticker used on early V6 cars).
I had my 3.4 re-engraved with an MG as it was going into an Mg. It confuses people who keep asking which model MG came with a V6.... I also used Fiero valve covers as they are much nicer looking than the stamped steel versions the 3.4 came with (but you need to relieve the underside of the plenum before they will fit).
You can have any lettering removed (sanders work well) and have the plenum recut with a computer operated milling machine to put the Fiero on it...
Yes, that's exactly what I was suggesting. Funny though, I don't think I've ever seen a picture of a 3400 upper plenum modified in that manner... which is a shame, 'cause as you know, the factory lettering on the 3400 intake appears upside down when that engine is installed in a Fiero engine bay.
[This message has been edited by Patrick (edited 10-22-2018).]
Funny though, I don't think I've ever seen a picture of a 3400 upper plenum modified in that manner... which is a shame, 'cause as you know, the factory lettering on the 3400 intake appears upside down when that engine is installed in a Fiero engine bay.
