addictedtotrack

Ok I know I have been posting a lot lately but I知 excited about the new ride!
So I want to be smart about the immediate improvements with my car. I intend to do the common bolt on including a good stout cam! The car is in my buddies shop until spring and I知 itching to do something! I want to be smart about this and do all the cool stuff but while I知 digging deep into this I want to address any and all items that would need attention or would be considered weak points. I MIGHT even try an autocross, it looks really fun. So let痴 hear it.... FYI the car only has 20k miles. Thanks everyone!

addictedtotrack

I'm hearing about guys doing Z06 diff and transmissions in there cars. is this an upgrade to my Z51? I thought the Z51 already has a good trans and diff?

HOXXOH

You might try identifying what you intend to do with the car, other than that you MIGHT try an autocross event. A stout cam is overkill for car shows and cruising. The trans and clutch are the weak points at the drags, when compared to the A6. Street tires don't work well at road tracks, are marginal for autocross, and awful for drag racing.
You bought someone's 9 year garage queen, so what's next?

Kenny94945

Sounds like you want a race car toy?
There are really no weak spots IMO.

Depends on your desires.
Cam - top end or low end?
Differential gearing Low of High?
Corner weighting and alignment?
All just depends as mentioned above identify what you want from the car.

Maybe if you want a do it all, find some compression and rebound adjustable shocks?
Adjust for drags, adjust for road coarse.
Maybe a second or third set of rims with autocross tires and drag slicks?

Yes, headers intake tune many mention as first step for performance.

Have fun.

JerriVette

Want to be smart? Leave the vehicle stock.

Stock the car is strong, balanced and reliable.

Without question the best performance mod would be driver training.

The 2009 corvette z51 manual is more capable than most street drivers...

Don't modify it...

Alright..maybe the seat ..put in a better drivers seat.....or just cinch the drivers seat belt before hitting the auto x...

Hope you don't mind my opinion and please don't take it personal. That was not my intention....

addictedtotrack

Thanks Guys! Jerri...I certainly welcome your advice and opinion, no worries brother. HOXXOH and Kenny you nailed it, I would like to do a little bit of everything. I suppose when I really think about it the car will be used the most in some.....lets just call it spirited street driving! As far as autocross/road race... I only have driven in 1 autocross event in my 73 TransAm just to try it out and the big block car is so nose heavy it pushed terribly! But with the right car I could see this being a blast! I have 2 friends that have (maybe both around 99 or 2000) Shelby mustangs that have already started bumping their gums about showing me whats fast when spring gets here and I want to wax their a$$e$
I raced karts for several years when younger. In my teens and early 20's I street raced a 67 Camaro a lot! In my 30's I ran an Allison legacy car for a few years, but I mostly let my son race it to enjoy some father/son bonding time. Now in my late 40's my kids are grown and out of the house and I want to go fast and have some fun while I still have some decent agility and decent reaction times LOL!
So yes Kenny! I want a race car toy that lets me have fun with a little bit of everything I enjoy. I can wrench on this car no problem. I have a 2 post lift. Before spring....My thought is to drop the entire rolling chassis out of the car and do all the performance upgrades, cam, full exhaust, Z06 clutch??(please chime in guys) Tick slave/throw out bearing, speed bleeder and adjustable mater cylinder(again chime in) Motor mounts and trans mounts?? Z06 Brkakes?? Ihave no idea what if anything needs to be done to the trans and rear diff. I just want to do what needs done while the rolling chassis out. All advice welcome!!

Ragtop 99

For spirited street driving, I would not rip the car apart. I also would not pour a ton of money into the car without putting some miles on it and determining what YOU think is lacking.

My thoughts are:
1) put the best tires on consistent with the driving conditions you have to deal with. If you can run an R compound tire because it is a fair weather toy, do that first. Then put some miles on and see what isn't up to the task. The stock clutch is more than adequate for hard street driving (unless the original owner did not know how to drive or beat on the car).

2) You could add a CAI, headers, and a tune right away since you'll want headers no matter what. Tuning with just bolt-ons is a good way to get the feel for this PCM as the car will drive ok with headers even before any tuning. Then decide how much more power you really want. A moderate bump form a cam or a big bump from FI.

3) I'm not a fan of the stock z51 shocks. they don't hold contact on less than ideal roads, especially under power. For a slight decrease in ride, good shocks can make the car feel more controllable on the street.

4) If your driving adventures will occur mostly at 130 mph and below, I suggest 3.90s or 4.10s. I have 3.90s and it really improve the fun factor and 4th gear still can reach 135 mph at 6,500 rpm. If you're thinking of staying NA, they complement a cam very nicely. At this point you can beef up the rear a bit if needed. The Z51 with headers/tune/3.90s/shocks/tires will feel like a different car. A cam or blower will then give it the big top end power.

addictedtotrack

Thanks ragtop! All great advice.....this is exactly the stuff I'm looking for to help me decide what to do. Even if everything I want to do is done in stages which is sound advice. I would like to build a road map that gets me there and stick to it!. All the feedback is great. I have a couple of questions.....

In regard to #3 above...What direction would you send me looking for shocks?

In regard to #4 above...Yes I want to stay NA. If I went with 3:90 or 4:10 gears are you suggesting to do that in my stock rear end housing? If so what do you mean when you say "at this point you can beef up the rear end a bit"?

I have been trying to read up on and get familiar with everything regarding this car. I see a lot of people doing Z06 rear diif and some doing Z06 transmission swaps too. I have seen guys doing ZR1 trans and diff swaps too. Are my Z51 rear diff and trans weaker in some way than ZR1/Z06? or is it more of a performance advantage? Should I be considering any of these parts for my car in the future?

Thanks for all the feedback and help everyone!

Boomer111

Not sure how well the 4:10's work with the Z51 spec trans. I have a base 2008 and I love the 4:10's, as Ragtop stated. Look to drop $2500 with installation incl.

Tires non RF summer performance and a tune would be entry starting point and really transform the car. Maybe another $1200-$1500 depending on your tire choice.

You have the Z51 suspension but things can always be improved, again depending on goals.

Just depends on your pocket book and end game.

Boomer111

#4 Most exchange their complete diff for a new reconditioned/built with all new parts except the case. This is checked for cracks and shoot preened. One from say RPI or as I did DTE, now Hoosiers.

They will rebuild an install new ring and pinion and then you can upgrade the axle shafts to stronger ones. Improved clutch packs and oiling and other mod options.

Go a search at RPI Transmissions or Hoosiers Engineering formerly DTE.

Both at one time and RPI still for sure are Forum sponsors.

I had my ring and pinion gears cold treated for strength and upgraded clutch packs along with the Z06 half axles. They offer stronger axles too.

You can choose the different stages depending on your HP target.

#3 Again depending on end use. Most will go with coilovers and here the price varies from mid teens to $5000. But coils for a street vehicle most will discourage this mod. Guys run it on the street and some like it but most will not.

Boomer111

http://hoosierpe.com/


http://www.rpmtransmissions.com/

J3TVETTE

The weak point is the Harmonic Balancer.

Ragtop 99

The Z06 rear is beefed up compared to the base and Z51 rear. Still, you don't see many people grenading the rear unless they are doing high rpm clutch dumps and or doing things to cause wheel hop. It's not easy (or at least wasn't years ago) to simply swap gears in the driveway. Most of us ended up doing swaps for units with the gears of our choice.

Boomer covered the popular options. I have a DTE and opted for some of the available upgrades, but not everything. I added the tranny brace too. As to gearing, I have 3.90s. With our transmission ratios, 6th gear is 72 mph at 2000 rpm. 4.10s would be 68 mph. I'd really like a little taller highway gear so 3.90 was my compromise. I like the short gearing in 1 - 5 and if you cam the car,the big gain is above 4000 rpm so gears make it easier to find that sweet spot.

Regarding shocks, every one has an opinion. Lots of threads on here about shocks. I had the Johnny O'Connells. The ride was firm, but handling and maintaining contact were noticeably better than stock. I had one fail and couldn't get a replacement so I recently switched to DRM Bilstiens. So far they feel pretty similar to the JOCs but I haven't had enough seat time on them to test them in each spot that I know was a problem with the stock shocks as my car was down for a while and now the weather is too cold for the tires. I also had Koni FSDs. I liked them as the ride was a tad better than the JOCs or the DRMs and and handling / maintaining contact was almost as good as the JOCs. However, between speedhumps and small potholes, they caused me to scrape too often so I took them off. Another option is adjustable shocks. They are more expensive, but half the price of coilovers. The adjustable shocks seem more popular with cars being set-up for drag racing as they make it easier to dial in weight transfer.

BTW, I also have heavier sway bars and that may color my view of the shocks. The combination has really flatten the car in turns and the steering responds quickly. The quickness of response eliminated the some of the sneeze factor safety margin in the stock set-up.

HOXXOH

I think I identified the weak point and it's not the car.

You want everything in the same car and that's exactly what you already have. The problem is that any changes you make to do something better, means something else won't be as good. So you need to pick what you'd like to do well and limit the mods to allow you to do other things, albeit not so well.

addictedtotrack

Hahaha..... I知 not completely clear, if it痴 not the car what else could it be!!??

Ok I feel you.....I want a nice corner carver with as much power as I can ring out of it naturally aspirated. I will attend maybe 3-4 autocross events a year just for fun and the rest of the time I will just enjoy street cruising. I was just this evening looking at the hot rod power tour dates and route. Also would like to take the car to LS fest. I won稚 be doing any official drag racing.

addictedtotrack

What痴 the fix for this? Drill and pin it? Aftermarket balancer?

addictedtotrack

Boomer thanks for all the time and effort you put in today! Much appreciated. I will be putting together a plan for the car this week. I may have some more questions if you don稚 mind?

addictedtotrack

Ragtop......you too! Thank you for taking the time to help a fellow member out! I may have more question for you to if you don’t mind?

Ragtop 99

I went with the ATI super damper 10% under-drive when I did my cam swap. Upgraded the chain too. My stock unit balancer was fine and I would not have touched it or the chain had I not done the cam swap.

Some have had problems with the balancer so it is worth an inspection to be sure there is no wobble.

There is an autocross and road racing forum and those guys can address mods for that if you want the car set up for that.

AORoads

I fully respect the knowledgeable advice from people like HOX and Ragtop. However, what Jerri and HOX are saying, and said two or three times is, YOU are the issue. The big problem is the driver, and the fact that you want to rip it up on the streets. And maybe hit a track eventually. That's where you need more training. Or the car you have today that excites you so much will be around a tree with you in it. Take your first $2K-$3K and go to a school like Ron Fellows or Bondurant. Or even, local HPDE's. Anything to give you some training so you don't hurt anyone.

Next, what you are saying is, you want it all, and it can't be all things, simply put. Do you understand? You change one thing to try to optimize one feature and it makes it worse or affects something in some other areas. The idea is "balance." Balance in the direction that it keeps most things going the way you can live with it, unless it's a completely, non-streetable, track car. HOX has been able to race his car a lot and STILL have 150K miles on it, +/-.

So, the advice to live with the car a little, get yourself trained as a driver, and then decide on what you want is good advice. We don't need any more Roger Rodas drives.

Good luck.