Help with my first swap please!

[phonedawgz]

The TH125C was an ok transmssion, back in 85.

Yes you need to replace the transmission if you want something decent.

btw I build Fiero swap harnesses.

http://reddevilriver.com

[ericjon262]

If you paid someone else to put it in yeah. But if you did it yourself it would cost about the same as an ls1 swap into a 3rd gen fbody does.

what bellhousing pattern dos the DI motor use?

[2.8/3400 1985 Camaro]

If you paid someone else to put it in yeah. But if you did it yourself it would cost about the same as an ls1 swap into a 3rd gen fbody does.

[ericjon262]

If you're going for that much power you should probably rebuild the transmission, transmissions usually last 150-200k typically. After seeing its a 3 speed from what the guy above me says though, I would replace it with a performance built 4t60. And actually for $6k you could get a 3.6 DI which has your power goals right out of the box, but its uncharted territory so far as I know. And paying someone else to figure it out would put you over budget if you couldn't do it yourself. Someone seriously needs to start cranking out standalone ECUs for that motor, I want a 3.6 DI in my camaro bad...as much power as an ls1 in a small lightweight, v6, could have my handling and my power.

I would stay away from the DI motor, it would have a ridiculous pricetag just to get in the car, and we're not talking running either. spend your money wisely, get an LX9 and a cam, have a fun DD, and a reliable car.

[2.8/3400 1985 Camaro]

Yeah, note my edit after I noticed it was a 3 spd, lol.

[ericjon262]

If you're going for that much power you should probably rebuild the transmission, transmissions usually last 150-200k typically.

I vote swap still, the TH125C is GARBAGE, it's my main reason for going 5 speed, not because my trans was toast, but because it was a crappy trans, three forward speeds, thats it. the torque converter lockup drops the rpm's more than the shifts...

[2.8/3400 1985 Camaro]

If you're going for that much power you should probably rebuild the transmission, transmissions usually last 150-200k typically. After seeing its a 3 speed from what the guy above me says though, I would replace it with a performance built 4t60. And actually for $6k you could get a 3.6 DI which has your power goals right out of the box, but its uncharted territory so far as I know. And paying someone else to figure it out would put you over budget if you couldn't do it yourself. Someone seriously needs to start cranking out standalone ECUs for that motor, I want a 3.6 DI in my camaro bad...as much power as an ls1 in a small lightweight, v6, could have my handling and my power.

[ericjon262]

Ok, thanks I will start reading up on the 3400/3500 swaps that have been done, if I have more questions I'll be sure to stop in.

Oh, I was looking at the longitudinal sbc installs specifically using the cradle from team321, but for the time being my budget doesn't quite match up with those dreams, so I will be staying in the v6 market.

What turbo would you use on a 3500? How much boost would it take to bring it into the 300+ area? How much will be in my capabilities (bolt-ons, some welding, decent knowledge of my fiero)? How much will I be turning to a professional for? Finally, guesstimates for a cost to 300 hp/tq.

I would start by finding how much the engine will set you back, mine set me back about $450 (38K miles) and then the trans, so then you can figure out how much you will have to do on your own. there's not much you won't be able to do if you have decent mechanical skills.


I wouldn't use the TH125C at all, it's a piece of crap, no overdrive, insane parasitic loss, ect. if you want to stay auto go with a 4t60 or one of it's variants, you'll be much happier, if you want to go manual, you have several options, the V6 four speed (ribbed case) the Fiero Getrag, The F23 (00-02 cavalier 5 speed) and the F40 6 speed (lots of work and $$)

as for what turbo, I'm not in the know on turbos yet, so I'll leave that blank.

$6000 if a pretty big budget, it ought to make for an awesome car!

[Josh-86SE]

Ok, thanks I will start reading up on the 3400/3500 swaps that have been done, if I have more questions I'll be sure to stop in.

Oh, I was looking at the longitudinal sbc installs specifically using the cradle from team321, but for the time being my budget doesn't quite match up with those dreams, so I will be staying in the v6 market.

What turbo would you use on a 3500? How much boost would it take to bring it into the 300+ area? How much will be in my capabilities (bolt-ons, some welding, decent knowledge of my fiero)? How much will I be turning to a professional for? Finally, guesstimates for a cost to 300 hp/tq.

[Kaiju Senso]

I would have to agree that if your goal is 300-350 then one of the aluminum head motors would be a better platform to start. The LX9 3500 would probably be the best place to start and there are a few of us Fiero owners who have a running, or work in progress 3500 swap to help you out if you get stuck.

I don't really know anything about auto transmissions but I believe I read once you start getting into that 300-350 hp/tq range, the stock auto trans' start needing some work to keep up. (The ones that come with the aluminum head engines, the Fiero auto is probably even worse)

[ericjon262]

based on your power and torque goals, I would say turbo 3400 or 3500. there was a guy near me with a stock 3500+turbo putting down 300 ft lbs, and he didn't really have much in the car. I would rebuild the transmission, are you staying automatic? the F23 five speed if supposed to be a solid trans that has the same bolt pattern as our motors, and can use stock fiero 5 speed axles. as far as automatics go, I would do a 4t60 or one of it's variants, The 125C is a total slushbox.

[Josh-86SE]

Also, with the mileage as high as it is should I be looking for a new tranny? Or do the new engines already require a tranny swap?

[Josh-86SE]

Thanks for all the input. I have been doing more research and am considering a few things, I have $6000 and don't mind using my local shop to do what I can't. I'm willing to entertain any ideas you guys still have but this is a basic run down of what I'm looking to accomplish.

First what I am starting with,

1986 SE Auto w/ 150k mi on it? I know it's rolled passed 99999 at least once and it sits at 62k now.
Access to 15+ parts fiero's on my uncle's lot.

What I want,
A V6
Around 300-350hp/tq, enough to be quick in town
Decent MPG 20+ preferred
Reliable
Boost
Room to move up to 400hp area

So can I build a turbo/SC v6 for around 6k? I can weld, never touched a turbo (would hire out for this), but have access to an uncle who has owned and built fiero's since they rolled out.

Thanks again,

Josh

[2.8/3400 1985 Camaro]

The swap itself is quite easy and straightforward for a 3.4, which is why I snagged one up for my camaro when I found out the PO was wrong or lied about HGs being the issue(cracked block, couldn't have it welded either as the coolant and oil passages were FUBAR). As for mods, I would throw a cam at it, port the heads, some roller rockers, an exhaust system, and one of the intakes, the DTB almost certainly flows more. The truleo might give more torque though.

[Kaiju Senso]

I'm not going to straight up try to push you towards a different engine then you suggested (seems to happen a lot on Pennocks...) The 3.4 iron head motor would no doubt the easiest engine swap/upgrade you can do. Rodney Dickman sells a kit to drill the holes for the starter and you can bolt on the heads, intake, and then basically plug and play with all your stock wiring.

Now, the point of the topic seemed to be about getting a little more power out of the 3.4. Obviously as stated porting your stock 2.8 manifolds and Y pipe is a must. I'm overall happy with my set of Trueleo headers modified for my 3400/3500 engine swap (I assume my engine was the one neophile mentioned) I can't compare to the headers on a stock 2.8 or 3.4 but I was having problems with the shift cables of my 4 speed Muncie touching the Y Pipe. If you have that transmission, expect a bit of modification because Trueleo's jig was built with the 5 speed manual transmission in mind. That's about as helpful as I can be because I don't have any first hand knowledge with any other products.

Though if you are swayed to try a newer, aluminum head engine swap, there are a few of us with first hand experience swapping into 85-87 Fieros. We would of course be glad to help with any questions. It's really not that difficult, only marginally more then a 3.4 and then you have wiring to deal with. It look longer to disassemble my Monte Carlo wiring harness then to actually connect the necessary wires. There are charts available from Sinister Performance (aka Darth Fiero on PFF) that ease the process.