Ok, so it's time for me to move on to another chapter with my Fiero. This time I won't be following the V6 route so I will ditch my mildly modded 2.8 in favor of more standard HP baseline and leaner mass. A family friend has given me a 1991 Grand Prix with a LO Quad4 engine "Vin D" mated to a 125c auto tranny. The Car has been sitting in their front yard for almost 6 months. I know is not the HO version but with minor modding it can reach that level. I always wanted a Quad4 and finally got my chance not to mention the whole car is free!

What I'm planning to do to get it started is rebuilt the whole engine to HO specs with new pistons, HO cams and damper, custom header (obiusly needed), and mild port and polish the 086 head. I will use ARP studs and bolts from Top to Bottom for added safety. My Fiero is auto from stock so I will just rebuilt the Quad tranny with a good kit (Alto probably) a good band, shift kit and higher stall converter (probably use the one in the quad). I will try to get a hold on another cradle to make the swap easier. What I'm planning is to put the engine running good NA for now. Turbo will be later since I have a T3/T4 hybrid laying around which also got for free.

I have done some searching and reading but need more information on what is needed to accomplish this swap. Now let's get to the questions.

1- How many engine mounts I need to fabricate to mount it in the Fiero?
2- Where do they need to be located?
3- Where can I get drawings of the mounting point fabrication if any?
4- Where can I find wiring diagrams?
5- What mods can be done to the 125c to handle 6500 rpms at least?

More questions later.

[This message has been edited by vEnOm (edited 03-02-2008).]

all I know is that my 12.8 second 3800 got slightly beat by some totally random guy with a quad4 turbo fiero, he tuned with a narrowband a/f gauge, and a FMU, stock ecu and #30 injectors. ( I gave him a little jump, because he had a stock autozone clutch)

The guy out here used stock trans mounts, one engine mount cobbled onto the front cross member, and a dogbone. Remember he had a manual... which really would be more efficent transmission than any stock fiero transmissions.

If your going to do an auto, your going to want to run a 4speed transmission, and toss the junk th125. Youll need a small amount of fabrication to make that happen, but in most cases, axles will be cake (or multi layered cake aka some assembly required)

Wirering is not much more than getting the grandprix harness power where it needs it, then messing with gauges. You will retain all of the "engine-ecu" connections when you remove the harness from the GP. Diagrams are availible around, somone else on here I bet has them.

Get that turbo going, and youll have one fast car. I wouldnt even want to think how fast this car out here would be with some real tuning.

Hmmmm, why did he used a dogbone? The other swaps I seen have only two engine mounts at the cradle. Is there a need for a dogbone at the top of the engine?

I will be doing the 4 speed auto with a 3.73 overall final drive but at a later time. I will need to fetch a good unit to get it started and unfortunately for me most of the good units are either in junkyards (asking around $400 for a pandora box tranny) or in line for the crusher. Getting parts from junkyards is very costly here in Puerto Rico.

On the other hand, I would like to level the engine as easy as possible so adding another variant to the swap would make things a little difficult. The 125c is not that bad of a tranny I have one in my Fiero V6. I've put it trough a lot of stress, 125 wet nitrous shot and 6K rpms shifts every weekend for the past 2 years and has not given up on me. Not to mention it drives me to work three to four times a week. Shifts are still very firm and quick.

Remeber this is just a start. I usually build in steps that way I have a before and after.

With an auto behind an engine making as little off-idle torque as the Quad 4, you might not really need a dog bone.. but consider that even the stock 4-cyl auto Fiero used a dogbone. The drivetrain does rock quite a bit without one, and you'll probably ruin some parts by slamming them into the trunk wall before you decide you need a dogbone.. so it's probably a good idea ;-).
Even with 4-point mounting with short stiff rubber mounts on my 3.4 DOHC it moved ~1/2" at the top at wide open throttle in 1st WITH a dogbone. Use one!

[This message has been edited by Steven Snyder (edited 03-03-2008).]

Sweet info. I want to do a Quad4 swap when I have garage space to rebuild one, but I want to use my existing manual trans.

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1986 Fiero SE V6, stock, auto, fastback. GT conv. Awaiting parts or sale.

1988 Fiero 4 cyl, Isuzu 5 spd.

1985 Dodge Ram D-100 Custom (318 5.2L V8)

I got a W41 Q4 from a yard a few years ago with the idea that I could build it and swap it into a Fiero as a high strung canyon carver type of build.

As technology marched on, however, I realized that anything I could do with the Q4, I could do lighter, cheaper, more reliably and just flat better with an Ecotec.

Find an Ecotec engine and transmission. You'll do better in the long run.

Does anyone knows what kind of engine mounts Fierobessed, Standard and bryson used? Let's see if they could chime in to clarify the dogbone confusion.

Will, I see where you're going. I actually want the ecotec also but the cost for such an engine here in Puerto Rico is about $1,000 and needs to be rebuilt since they have em sitting in an open space taking direct water and sunlight. Add to that ECM, tranny (I dont know if the stock bellhousing is compatible) and whatever else is needed and you may be floating around 3K. With that same amount of money I can build me a super Quad. Hell I can even change it to stick.

Note that the whole car with engine and tranny is for FREE.

there is no "confusion" per say in weither nor not to use a dogbone, its really your choice. You need 4 mounts total, so if you put it on top or under the motor it doesnt matter.