racerboy

Subject to PPI I am looking at buying a 91 C4 and I want to make it into an awesome street car that I can occassionally take to a DE. This particular car has 95K miles, already has suspension and wheels and a chip but the rest is pretty much stock. My plan is to buy the car and send it right to the mechanic, so what do you all recommend? My thoughts are:

Short shifter (what kind?)

Front strut tower brace

Replace primary or secondary muffler (which do you recommend?)

Stainless braided brake lines

Possibly poly bushings (which would be worth changing out?)

Also thinking about aligning to RS specs.

What do you all think of these mods? Anything else I should add or have the mechanic do while in the shop? Please keep in mind this will be my daily driver (although I won't have to drive it everyday) I want it to be comfortable, driveable and liveable. Thanks!

ilko

I would just drive it for a while before spending a bunch of money on it. That way you can see what you are happy with and what you would want to change. Good luck with the new car and post pics when you get it

racerboy

Thanks. Normally that is what I would do, however I am buying the car and shipping it cross country to CA and want to have my mechanic in Connecticut do all the work (guy I have know and trusted for years) before I ship it out here. I can save alot of money and time this way and make certain that a quality person that I trust is working on the car.

rotorheadcase

Can't agree more.... Drive the s^!t out of it and decide what characteristics you like and don't like. C4's are a bit of a mixed bag as to how they handle depending on what has been done by the previous owner.

That said the car will definitely benefit from RS spec alignment but all the other stuff is just...well...stuff. Most of us end up doing all that stuff but to be brutally honest and out of earshot of my wife, the basic car is fantastic. This was one of THE supercars of the early 90's and it can still hustle when it's cranked up.

You'll end up on the slippery slope soon enough but for the time being just drive it as much as you can and keep it out of the clutches of your neighbourhood mechanic whilst you can!!

Regards,

Neil

ilko

In that case, if you trust the mechanic ask him what he feels needs attention. I would stick with the OEM shifter, but it's really a personal preference. The strut tower brace would help. Also you might want to look into 225 wide tires in the front to help reduce understeer. Euro RS alignment, corner balancing and ride height would be great as well. SS lines are unnecessary, there are no proven benefits for them in our cars. The bushings could be worth it, but again it depends on how you like the feel of the car. I replaced the secondary muffler with a G-pipe, it provides better weight savings. Others have done the primary muffler and swear by it. Have fun!

racerboy

Yes, I trust him fully, he has been a long time family friend and usually charges me like 25-35 an hour cash. I am going to do the brake lines because when I track the car it makes sense to have them, plus the rubber ones are coming up on two decades of use, right?

I will definantly ask his opinion and regardless will change all the fluids, bleed everything, change belts, etc just as good practice. Knowing myself though, I can't keep things stock for very long, every car I've owned I usually do a combo of intake/exhaust, shifter, suspension, brakes, etc within a month of purchase so I want to get some of that stuff out of the way when it's cheap and easy. Keep the opinions flowing...

jimq

on the track you should use factory brake lines as you can not see if the lines are bad when incased in the mesh.

sullivs

Hey Racerboy,

Ditto to all the other comments previously listed. Your car is pretty awsome already. Most of us will never be able to fully utilize the real potential of the car. What will make it even better is to improve the nut behind the wheel. Go to DE's, read up on improving your driving skills, take as many lessons as you can. Become a smarter, more informed, courteous driver, and you will really be able to get the most enjoyment out of it. Be safe, learn something, and have fun along the way.

Steve

911skb

There's a thread in the 964 forums about dialing in the suspension on a C4. Should be able to find it with a quick search. Go through that list with your mechanic, see if everything has been done.

I don't think you can do the LWF on a C4, otherwise that would be a nice mod.

Search here for "diet" also. Gives good ideas of how to lighten up the 964's.

Maybe a set of Big Red brakes. I know my stock brakes surprise passengers already, but have heard good things about the Big Reds.

After that, a 3.8 ltr upgrade

Also, search for posts by "kgorman" he has a dialed in C4 for the track. Maybe too aggressive for the street, but probably good ideas.

1990-964

Hey there,

The short shifter is a nice mod I have one and love it, but use the factory piece. You will need to verify that you can use one in a C4. The strut brace is definately worthwhile as are most of your other ideas. Don't forget about the suspension though. The RS spec alignment will only be fully realized if the suspension is set up properly. Good Luck

racerboy

Steve- I understand what you are saying, but I should have prefaced this by saying that I did the whole Skip Barber thing, ran karts for a few years ( 125 rotax and shifter), ran my own SCCA car for a season, done DE's in my fathers SCCA ITE mustang and run HSR in his 680hp IMSA car. The 964 should be quite tame in comparison but I'm just looking to have some fun for the next few years before getting back into racing.

Marc Shaw

Things to consider.....

Exhaust:
cat. bypass or high flow cat
primary bypass (more power) or secondary bypass (more noise)
...or just go heater-less and put in headers

Intake:
remove the barn-door and put in a hot-film MAF
skip the K&N or cone filter
a custom chip to match on a rolling road

Suspension:
it has been "done" but is it any good and is it new?
Euro spec alignment and corner balance
increase negative camber for cornering - may need camber plates
front and rear adjustable sway bars (TRG are good)
front strut tower brace
replace bushings if tired (PowerFlex are good I am told)

Gear box:
I've never tried a short-shifter so can't comment but the stock one is very good

Wheels:
lighter is better, or course
MPSC tires

Brakes:
s.s. lines
Big Red brakes (turbo calipers and disks)
Pagid black or yellow pads
good, new brake fluid

Just my opinions and others will disagree. The bottom line though is that the more you make it a track car, the less you make it a comfortable street car.

Marc

JohnMetro

Hi Marc

thanks for all the tips. Is it possible to "shorten" the list to mods that WOULD suit a street car? By that, I mean things that would improve handling and performance, without compromising the comfort and reliability too much

amfp

If was me, I would be more concerned about safety of existing parts, not upgrades. Look at replacing brake hoses with rubber stock hoses, check tie rods, sway bars, brakes, etc. I would use your friend to spend hours to do the PPI on the car, including leakdown, if it really is the right car. However, if you plan to track the car a lot, I would spend more time looking for a C2, not a C4.

racerboy

I don't plan on tracking the car alot, just a few events a year, maybe some auto-x for fun.

It will be my only car but will really serve as my weekend toy for trips to Monterey, Santa Cruz, Napa, but also has to get me to Tahoe in the snow to ski, hence the C4.