My reason for choosing the 3.4 TDC over other engine swaps is because it is a V6/60 engine. It still feels a lot like the 2.8, but with a higher redline and a lot more top end power. It's more like the ultimate 2.8, than something with boatloads of torque but not much top-end power (3800, SBC).
Off the line, it's about like the 2.8 with a bit more power (probably mostly due to the displacement increase). Like the 2.8, at about 3000 rpm is where the real power starts to build...unlike the 2.8, there's a whole lot more above 4000 rpm, and it pulls hard all the way to the 7000 rpm redline. Rated peak rpm is only at 5200 rpm, but it feels closer to 6000 rpm, and the power does not drop off much until you near 7000.
The engine is relatively rare, so performance parts for it are pretty much nonexistant, and some of the replacement parts are very expensive. (I've heard lifters are $25 each, and there's 24 of them!). Timing belt and idler pullies should be replaced at least every 60k miles. (Luckily those are cheap, you can probably get all the parts for $100 or so.)
I bought my car with the conversion already done, so I don't have all of the specifics of how everything on my car was done, but I had been researching the swap for some time and planning on doing one myself, when I found this one for sale for a good price.
Do you want to know how it was installed, or how I would install it now? :) There are some things that I plan to re-do eventually, when I pull the engine.
Right now, the engine is mounted to the stock Fiero V6 front engine mount. This is the most common way of mounting the engine. My particular setup has 2 half dogbones, one on each side of the engine. One just to the left of the forward cylinder head, the other attached to the engine lift hook bracket.
Everyone I know of seems to have a different dogbone setup, and many have had problems. When I re-do my car, I will be swapping in an 88 rear cradle. I may switch to the original 3.4L side engine mounts, in the hopes of reducing side-to-side movement of the engine to hopefully cause a little less stress on the dogbones. The forward dogbone I am not too worried about, that is the stock dogbone mount. It's the rearward one that worries me, as Michael Smith had a similar setup and he cracked his front cover in half after breaking a motor mount. Also, the rearward dogbone sits *right* under the "braces" of the decklid. The right side one had to be cut down so that the dogbone would fit. (see the line on the top of the round part of the dogbone, it still rubs a little bit.) I don't think it would be quite as bad if the car was a GT, I think the decklid sits a little higher relative to the engine.
The engine is bolted up to a Fiero Getrag 5-speed, using stock axles, etc. The only problem there is that the ECM expects a newer-style VSS signal, from the VSS sender that is built into the transaxle on newer cars. There is a solution to this now, with a custom PROM and a little rewiring, the ECM can be made to accept the Fiero's original VSS signal. Or you could use a trans out of a Grand Prix and (possibly) use Rodney Dickman's FWD Getrag conversion kit. Or build a circuit to convert the speedo signal. One of these methods is definately needed as the ECM is very unhappy about not knowing how fast the car is going, even with a manual and has a tendancy to want to die as you come to a stop.
I do not know for certain what my fuel pump is, but the stock one should be adequate, at least with a stock engine. If it ever dies, I will probably replace it with one for a 3800SC anyway, just to have a bit of extra capacity. My car has V6 Fiero fuel lines rerouted, with some custom tubing between them and the engine. (see the 2 hoses under the air intake tube.) 4cyl Fiero lines look like they would be an almost perfect fit, except for the fuel filter.
On my car, the ECM is mounted directly in front of the junction box in front of the former battery location. (lower right ). I plan to put it in the stock ECM location and reroute the wires. I plan on putting the DIS ignition module and coils where the ECM is now, instead of being bolted to the block, sandwiched between the starter and forward exhaust manifold.
The upper pulley shown in the same picture is just bolted to an aluminum plate, a lot of people just leave the power steering pump there and loop the lines.
You must remove the decklid torsion bar and part of the right rear decklid support so that the front cylinder head will fit. I'll probably go to a gas strut setup like Rodney Dickman sells eventually.
The spark plug wires have hard plastic boots that are over 6" long. (Centrally mounted sparkplugs, the wires go down between the cams.) You cannot pull the front plug wires out intact. Breaking them in half before installing worked for me, but that will put a lot of stress on the wires when they are removed. I hoped I wouldn't need to remove them until they needed to be replaced, but I just had to so that the spark plug sockets can dry out, hopefully the wires will survivie. I also now have a flat sheet of rubber covering the front valve cover to prevent water from getting in the spark plug wells. :) I know one person with the original 3.4 side mounts, and he says he can change the front plug wires, so I think they either slightly change the mounting angle or mount the engine slightly rearward, so that the wires are more easily removable.
The 3.4's stock exhaust setup is like most other recent GM FWD's. The front manifold is similar to a fiero manifold, there is a crossover pipe to the rear manifold, and the rear manifold has an outlet near the middle that goes to the rest of the exhaust system. You can cut the trunk out and build off of that (what was done in my case), or you can get another front manifold for the rear, and have the crossover pipe modified to a Fiero-style Y-pipe and connect it to the stock or similar exhaust system.
Some people have suggested using the 3.4 TDC block as a donor block for a 3.4 FWD pushrod engine...but it cannot be converted to pushrod heads because there are no holes for the lifters.
I thought about trying to go the other way - using the Bowtie aluminum block with the 3.4 TDC heads. However, from what I've heard, the water passages are different, so the heads would not match up to the block.
How is performance? I took it to the dragstrip once, not too long after I got it. Only my second time there (first time with this car), so I'm not exactly an expert, and my times were nowhere near good enough to brag about (best was a 14.5). I let fellow Daytona Fieros club member Elie make a run run in my car, and on his first time ever driving the car, he managed the quarter mile in 13.957 @ 96.49 mph.
