964 Modification Help
 

My 1994 964 C4 is having its engine pulled and resealed (oil leak). While this service is being completed I thought this might be a good time to look to modify the engine for better performance. Does anybody have any suggestions? I was thinking exhaust, but which one? I want the most bang for the buck with the least amount of stress on the engine.

Thank You in Advance

Lou

What do you hope to accomplish from the modification(s)? A beter exhaust and new chip may get you some hp (20ish?), but you don't need the engine out to change them.

With the engine out, I would say the best mod to do would be a lightweight flywheel with RS clutch and to add an LSD if you don't have one. After that, I think suspension modifications provide the most benefit (as opposed to engine mods).

How much were you planning to spend?

Lou, you just opened an incredible can of worms! Good for you -- but you have a question to answer before anyone can help -- how much do you have to spend?

We could get you for $15000 in a heartbeat, y'know, by developing the engine with a 3.8l rebuild and regearing the transmission. Another $10k for suspension with remote reservoirs for the shocks with lightweight wheels and serious tires.

But if all you want is a good-sounding exhaust, we can recommend, again, the expensive (do you need emissions tests where you live and register the car?) with headers, cat bypass, and dual outlets. Or just a catback unit -- you might visit the Fabspeed website where they have nice wav files for the different exhausts they carry for this car. And the cheapest, and most enjoyable for my money (some claim it makes torque gains to boot) is to just eliminate the secondary muffler (right rear) with a "G" pipe bypass.

Hang on. There's lots of folk here who will be eager to spend your money for you. You might find more helpful suggestions if you can give us an idea of your budget and what you'd like to accomplish.

And if we do a good job, join Rennlist. It's a great place. Welcome aboard. Joe W. :cheers:

(Edit: Not repeating Tom on purpose -- typing while he was posting ... sorry for the duplication!)

964s respond well to cam changes;)

Bill,
How? What cams? higher lift, longer duration or overlap?
I've been researching and was told the effect is more one of shifting the torque curve up or down the rev range, no across the board increase in torque possible. True?

pzull

All I can say is that we are using longer duration cams in my engine but as they are only a tiny part of the modifications being performed I would not be able to quantify the gain attributed to them...once the car is run in, I hope to be able to show that there are considerable gains to be had on a 964 but also at a considerable cost of course.

I'll agree with Tom. A lightweight flywheel and clutch replacement (if necessary) would be timely.

Other little things... I'd put in RS motor mounts (and possibly tranny mounts) while the engine is out. Then I'd adjust the valves and replace the spark plugs (and possibly wires). Finally, I'd rip out (or replace)the sagging foam insulation piece that sits under the firewall.

Erick

You can't gp to crazy w/ duration and retainthe stock air metering system. There are several good candidates from Elgin, WebCam and others. I have seen very impressive #s approaching 300 flywheel w/ WebCam 993SS cams, larger valves and mild port work, rod bolts were also updated and a custom chip was burned, but an otherwise stock 964. Hp and torque are improved through out the extended rev range, but the percieved powerband does become narrower. It help if the upper 3 ratios are closed up somewhat but it's certainly not necessary.

Christer, longer duration with I assume more overlap? Can you remember how much overlap and cam timing?

Doing cams with rebuild + change of engine management increases projects costs by only a little over the same project without cams.....I regret not doing it all at once, which is why I need to justify a major project with more increase in bhps now having done a "halfway" job on rebuild without cams + engine management. Still searching & hoping the Techart CT3 kit is still available

Forgive me for even bringing this up, but the E36 M3 (even the US version) is capable of making 100bhp/liter (albeit with some extensive mods). These mods would include your basic bolt ons, plus a good tune, and cams. One guy I know of is making 265rwhp with the 3.0L. You could probably duplicated what he has done for about 8 grand. Is this simply due to the fact that the M3 has an insanely high flowing head and VANOS? Will the 3.6L from the 964 ever come close to 100bhp/liter without dropping 20k+? I really love these cars and realize power isn't everything, but 300bhp seems fairly reasonable. Let me know what you guys think.

I'll let you know what I can actually prove when my car is run in. Obviously I dont know what the figures will be , but I would certainly expect 300rwhp+....

Are you kidding - I don't know that....:D In any case, I guess all that has gone into my engine will be in synergy with all the other mods so even if I knew that it may not be of use. I am doing everything at once, i just couldn't sit there for years doing cat by pass, G pipe, then cams, then Motec or whatever - IMHO it is best to do everything to get maximum synergy. The project will not stop here, but it will certainly be on hold for a while so we can see what the current modifications bring as far as pwer, driveability and practicality....

The proof will be in the pudding, and I will let you know whatever those results are...