Dange

So I am coming from a 230hp mazdaspeed miata full suspension, 4 point roll bar light wheels and 225/45/15 hankook RS3's all around long story short the car got totalled out. So I decided to jump up to a more capable platform, I always loved corvettes, and they are really the only car that is consistently pulling the top spots in most racing along with the miata. So picked up my new to me 99 corvette targa. and I would love to pick some of your brains and get some opinions so I can sort out my chassis a bit before i focus on power.

I am really missing how nimble and composed that car was set up and Id like to get that feeling back. I'm betting im probably the only person here ever to want my corvette to be more like a miata lol. Well i got back in the miata and i realized other than the vette being heavier and bigger feeling which really cant be changed. the things that stick out to me. is the slower steering rack. the worse turn in. and lack of stiffness..
the vette will be mostly DD duty. weekend warrior, the occasional trip to the dragstrip, occasional autocross or short track. so i dont need something full race quality. I am not competitive, i just drive for fun. ive pulled a few FTD's at local autocrosses with the msm but i dont pay attention to classes, or points i just like to go out and take some turns.

from doing a bit of research im guessing coilovers, tunnel plate, and swaybars are first on my list.
first question is how do the c6z51 sway bars stack up. is it worth it to spend the 600 on the pfadt C5 Johnny O'Connell Sway Bars? maybe a different suggestion?

if i switch to a "squared" setup. im really looking at the TSW nurburgring 18/18 setup in 10.5 wide. but will this improve my turn in? I noticed that the vette stock is a little sluggish with quick inputs when out playing about on a curvy road. great with sweepers. but its not as sharp as I want. i understand more tire out back tends to dial out the oversteer thats common in a FR platform with this much torque. but with a good alignment and sway preload im pretty sure that can be tuned out and made pretty neutral or am i completely wrong?

finally What tires are people running for a vette that sees the occasional trackday? the allseasons on it now I really dont like. i Daily drove 140treadwear RS-3's on the miata because well at 100 bucks a pop i didnt mind changing tires every year. and the light weight let me get a surprising amount of miles out of them. I'm noticing that wont be as friendly on my wallet in this car. so im guessing something UHP summer. first set that sticks out to me is the BFG KDW. is there something better?

anyway. I appriciate your time and help.

MY03C5Z

Congrats on getting your c5. You'll probably get a lot more help if you post this in the c5 general section. There is a lot more activity over there, this section is c5 z06 specific. As far as tires the nitto nt05's are a great street/track tire. I have them upfront, want to get a pair for the rear too. Im running stock 17/18's and haven't had it on a roadcourse yet. This car handles very well in stock form (z06) so I cant suggest any suspension mods. So far Ive just been concerned about hp mods. Good luck!

mobius

Nt05 are decent but there are a lot better options out there. ran them on a 430rwhp vette and they spin easy and you can push the front end easy (understeer). This was on a coilover car. R888 are way better. if you dont want that aggressive the pilot sports are awesome.

Solofast

Actually the place to ask the question is on the roadracing and autocross page in the general section. That's where folks who have been there and done that really hang out.

The first thing is that the car is already a Z, so as far as road work and serious setup, the basic parts are already there. If you aren't looking for serious track duty you just need to set the car up properly and the difference will be amazing.

First of all, you want to sharpen the handling and make the turn in more crisp. The things you need to attack are the front suspension bushings, the tires and the alignment. Only after you've done those things, and if it still isn't racy enough do you want to spend the $ for big suspension changes.

Number one would be to upgrade the front bushings to poly or delrin. I know they tend to squeak, but if you do some searching there are some that are much better than others in that regard.

Second thing is to lower the car about 3/4 of an inch and get it cornerweighted. You want not only sharper handling, but you want the car to turn equally in both directions, and cornerweighting it is the right thing to do. Do not get greedy on the ride height. These cars don't have much travel to start with and the one tired and true method to screw it up is to lower it too much. Other fools will chime in and say the've lowered it more, cut bushings or used longer bolts and their car handles great, but they don't understand that riding around on the bump stops feels like a go kart, but when you are serious corner carving it will go to crap on the first bump.

While you are corner weighting it, get it aligned with a serious performance alignment. If the car isn't going to the track much you can use about 1.0 to 1.5 degrees of negative camber in the front and about .5 degrees less than what you put in the front in the back. Front caster is as much as you can get. Rear toe should be about 1/8 of an inch of total toe in.

Front toe is a key setup variable and should be adjusted to taste. About 1/8 of an inch of total toe in up front I find is a good compromise. Big negative camber in the front does wear the front tires more, but it's not as bad as you might think. Front toe out (as used by more serious track cars) will make the car turn in like it's on rails, but that tends to eat front tires, as well as make the car tramline (follow ruts in the road) and can get scary in the rain. For that reason you want to adjust toe to taste, and you can go to zero toe up front without a big tire wear penalty. I would suggest that you mark the front toe links with a stripe of paint across the tie rod ends and onto the tie rod. You can then fine tune the toe by turning the links equal amounts on both sides. One full turn from 1/8 of an inch of toe in is about equal to 1/8 of an inch of toe out. If you start at 1/8 of total toe in, then 1/4 to 1/2 a turn will give you a bit less toe and will provide sharper initial turn in.

If you do that kind of setup, you will have a very different car and it will be a lot more sharp and be more fun to drive. Proper setup can really wake these cars up.

Next on the list is shocks. If you've done all of the above, and if you don't have a 2004, get a set of the Bilstein sport shocks. They are valved perfectly for this car and give really good grip and handling.

As you might realize, at this point you really haven't spent much to get a really good driving car. The stock Z springs and bars are a good package and are plenty stiff for street work. Coilovers for a street car are just a waste of money.

If you do all of the above, and still find it wanting, you can then think about a bar upgrade. I'd consider doing both front and rear to keep the car balanced, but those who have done the T1 bars find them really too stiff for the street. You need to go somewhere between stock and T1 if you want a liveable street package.

Suspension setup is 99% gettting the right package dialed in, and unlike horsepower upgrades, it generally doesn't cost all that much if you know what you want to do.

SoDiezl350

For me the biggest difference came from a racing steering wheel. The weight and diameter of the stock unit completely kills all feedback you get from the car.

Of course eventually I ended up going with Pfadt Featherlight coilovers, poly bushings, and JOC swaybars. In the end, going with the steering wheel and a nice set of tires made the difference. I hated the way the car felt at first.

SoDiezl350

NT05s can't compare to R888s for a reason. I really like the NT05s and if I was to recommend a stickier tire I would suggest the NT01 over the R888.

I'm currently running 17x9.5 and 17x11 C4 Grand sport sizes. I can get the NT05s in 275F/315R sizes for 750 shipped. The NT01s come out to around 825 shipped.

Dange

solofast. thanks a ton some amazing info there.
I posted here because the z06 forum was the only c5 subcatagory labeled with suspension. but I dont have the z06. i have a 99 targa but ill probably go about seeing if a mod can move this over or repost over there.
I love the car in general I just have a few nitpicks and the sharpness is the main one. great to know a few mods will wake it up.

So how about the c6z51 sways? think thats a good middle ground between the stock and T1 bars?
I definately need to look at new bushings as old as my car is the stock rubber is probably pretty worn out.

Ive definately been thinking about swapping the wheel out. it is kinda meaty feeling.

and what kind of mileage are people seeing out of the NT05? nt01/888 are great but i dont think i can afford 1k in tires every couple months on a Daily driver. so 5k or less is a bit out of the question. id like to hover around 15-20k miles between changes. granted more would be better.
I have Pilot Sport A/S Plus on the wheels now. im not thinking that i am to happy with them.

mobius

Go with something like a ps2 vs a nt05. I was much happier with that tire it performed very well and lasts decently.as for the nt01 vs r888 each is own.... Just giving my opinion.

As for the guy saying coilovers are a waste? Seriously... I assume u haven't driven on coilovers. Night and day difference there is no comparison... Especially when the op is saying he wants more nimble better turn in feeling.

2K3Z06

I had a 04 MSM, it was a great car. The balance was great, and in many ways, it was more fun than my Z06. I put more miles on the mazdaspeed than my Z06, because it was simply more fun to drive, even though it was slower than my vette.

The vette, has the power that sportscars guys love. But, as you know, its a big and heavy car, with a long wheelbase and wide stance. you have to slow it down to get through a corner, a use the power to rocket out of the corner exit. the mazda will carry more speed through a corner, but lacks the acceleration down the straights.

The vette will never be a agile as a miata, its just too big and heavy. But can have faster lap times with all the power on tap.

The classic sportscar battle, big heavy car with monster power VS. small, lightweight car with decent power.

Welcome to the vette world.

Omaha02Z06

Some great info posted above for car setup.

Sadly they good street tires like the RS3's don't come in our common sizes. For something that you will still have fun with at the track and last more than 5k and not break the bank you are looking at Nitto NT05's, Kumho XS's (whenever they come back in stock), or Falken 615's. My last NT05 set lasted around 7k I'd say. There was still a little tread left but they were shot. The grip didn't last to the end like the Hankook RS2's I had on my old car.

Solofast

That's a slightly different kettle of fish. The C5Z is a lot sharper than base car and if you are willing to go a bit stiffer, the complete z06 package will be a huge upgrade from where you are now. There is a chart on the Pfadt site that has the relative sway bar rates on it, and you can pick a package that will really help the car. You can often find a set of springs and bars in the C5 for sale section and get a complete package for not much money at all. If you are going to do it piecemeal, get a set of bars and then shocks and probably then springs. For shocks the Bilstein sports are the best choice in terms of bang for the buck. They are about 50 to $70 more than the C6Z shocks but they are a better match for your springs and will last longer than stock shocks.

All of the alignment and setup stuff above still applies. From where you are now there is world of improvement available for not much $.

Dange

ahh ok. looking at the chart. I am kinda confused with GM's engineering. they install thinner front tires and wide back tires which creates understeer. and then install a equal or even stiffer rear sway bar which creates oversteer. It would seem like a recipe for snap oversteer.
i dont know if it was to compensate for the necessity for wide rear tires for straight line traction or what.

So what do you all think about this plan.
Im thinking about keeping my rears 10.5 but going with a square wheel setup. 18x10.5 all around and then something like a 275/35 front 295/35 rear to guard against a little power on oversteer. and still give me the slight size difference required to keep my TCS/AH from freaking out.
and then either c6z51 sways seeing they are only 200 which are still relitively small increase. or a set of the pfadt jonny oconnels that are 600.
going by the chart to me a jonny oconnel front sway with a gm T1 rear sway would be a perfect setup. but i cant afford 2 different sets lol.

Solofast

You are pretty much right in that bigger rear tires need more rear bar to balance it out. It won't snap oversteer unless you are on the bump stops. You pretty much always need to balance tire width changes with more bar, no matter which end you are working with.

That said, a 275 up front isn't as big a change, but the stock Z bars balance well with a 275/315 setup. Don't be afraid of going a bit bigger in the back too if you go bigger in the front.

The GM T1 bars are brutal on the street. Unless you are tracking or running the car they are really a track only thing.

john8642

This post was very informative for me (speaking as one who has only had my C5Z for about a month). It follows the OP as he make several mods for HPDE, and tells how well they work. I think the best advise is to drive as much as you can and become familiar with the car.

http://forums.corvetteforum.com/auto...e-learned.html

Atok

Sounds like you bought the wrong car for what you want to do. You need a Z06.

Solofast

Well yes, to a point, but remember as Zora Duntov said in that famous film clip..."all Corvettes are the same it's just a matter of degresze"... And I've be looking for that special grease for a long time...

The OP can very quickly upgrade to a set of Z51 or Z06 suspension parts for almost nothing and have essentially the same setup. Lots of folks go to coilovers and you can pick up the parts you need used for a song. The Pfadt Jonny O bars are a good upgrade and aren't crazy stiff too, so there are options. If you already have the car and like it, it's so easy to upgrade that in most cases it's worth it. I have a Z, but there are times when a hatch back there would be nice to carry the extra stuff once in a while. If you aren't going racing or super serious track day workouts, the targa body is probalby more liveable on a day to day basis.

Lastly, if you want to sharpen it and the car is old and needs new bushings anyway, you can get a set of the T1 control arms that have stiffer rubber bushings in them and that will also sharpen the handling without going to poly bushings and putting up with the hassle of keeping them lubed and the squeaking that results.

Dange

thanks everyone lots of great info. ill have to get going on it.

solo- will 315's even fit on a 10.5" wheel?

believe me I wouldnt have turned down a white z06. that would have been great. but this car was a good find and at a great price so i couldnt pass it up. and to be honest I wanted the targa. I can run around top down, seeing as ive owned convertibles most my adult life. but its still technically a hardtop so no special hoops to jump through for trackdays.
if i was going to compete. id agree with you. but the targa just fits my needs a bit more.

Solofast

Easy, no problem. I run 315 Hoosiers on the back most weekends

Actually the STOCK C5Z wheels are the lightest and best bang for the buck that you can do for wheels for these cars. You can pick up a nice used set for under $600 if you look around. Perfect sets are a bit more, rough, racing wheels go for a bit less, but they are out there in pretty good numbers. Those wheels, (not aftermarket Z wheels, but real Speedlines or Alcoa's) are really light too. You absolutely can't beat them in terms of getting a bit more wheel and tire under the car for the price.