$$$$$$
Suspension Question...how to decrease nose diving..
Thread Starter
Burning Brakes
Joined: Nov 2006
Posts: 1,098
Likes: 0
From: Yorkville IL
Suspension Question...how to decrease nose diving..
I have a 2009 C6 Z51. I went to slightly lower profile tires..
Stock 245 40 18 front
285 35 19 rear
new 245 35 18
295 30 19 with R6's
The car lost some height so under moderate or hard cornering and braking I'm scraping the front undercarriage plastic air deflectors. I only have about 1 inch clearance in the front from the plastic air deflectors . I have a procharger with intercooler that sits low...this is what I'm concerned about ..it only has about 2 3/4 inch clearance.
Can the suspension be tightened down to prevent too much diving so I don't bottom out...if not I'm afraid to run my new setup on the track...
Anyone have an idea how much my suspension will 'give"....more then 2 3/4 inch?
any thoughts
Stock 245 40 18 front
285 35 19 rear
new 245 35 18
295 30 19 with R6's
The car lost some height so under moderate or hard cornering and braking I'm scraping the front undercarriage plastic air deflectors. I only have about 1 inch clearance in the front from the plastic air deflectors . I have a procharger with intercooler that sits low...this is what I'm concerned about ..it only has about 2 3/4 inch clearance.
Can the suspension be tightened down to prevent too much diving so I don't bottom out...if not I'm afraid to run my new setup on the track...
Anyone have an idea how much my suspension will 'give"....more then 2 3/4 inch?
any thoughts
Race Director
Joined: Sep 1999
Posts: 12,422
Likes: 905
From: CONCORD NC
the easiest thing would be to raise the ride height. Stiffer springs/shocks would also help. If you actually want to reduce "dive", then you need to remount the control arms to change the roll centers.
You raise the front by turning the adjusters in each end of the leaf springs. However, unless you intercooler is lower than the steel radiator support (nerf bars) you are probably safe. If it hangs below that, you WILL hit it eventually regardless.
You raise the front by turning the adjusters in each end of the leaf springs. However, unless you intercooler is lower than the steel radiator support (nerf bars) you are probably safe. If it hangs below that, you WILL hit it eventually regardless.
Thread Starter
Burning Brakes
Joined: Nov 2006
Posts: 1,098
Likes: 0
From: Yorkville IL
Team Owner
Joined: Sep 2003
Posts: 43,084
Likes: 33
From: Raleigh / Rolesville NC
Safety Car
Joined: May 2005
Posts: 3,520
Likes: 3
From: Redwood City CA
FWIW, I had PFC 01 / PFC Z pads the first couple of track days and the nose dive was crazy. When I ran matched brake compounds F/R the car was MUCH happier. I didn't really care for the KONI 3013Sports I tested on the car, but the ability to crank in some rebound certainly helped. I am pleased with my DRM [non-adjustable] coilovers...
Former Vendor
Joined: Oct 2007
Posts: 2,713
Likes: 9
From: Morgan Utah
It does seem your car is probably to low so if you want to go faster on the track you might need to raise it up to where the geometry is correct. We cannot lower these cars much without giving up far to much in handling.
Though some run their cars really low and seem to feel they work well for them if all things are set correctly with a higher ride height(correct height) the car will be faster and should be easier and safer to drive fast in all conditions.
Brake pads, I generally run one compound softer in the rear with no issues but have not tracked my C6 yet, it seems your are quite a bit different. You can run much bigger calipers in the front versus rear on most cars, bigger rotors as well, deals with the heat better, and match up the compounds to the task.
If you still have the problem and do not want to change springs then at least some adjustable shocks could help, keep stiffening them up until the problem gets better though this is a bit of a bandaid approach.
Though some run their cars really low and seem to feel they work well for them if all things are set correctly with a higher ride height(correct height) the car will be faster and should be easier and safer to drive fast in all conditions.
Brake pads, I generally run one compound softer in the rear with no issues but have not tracked my C6 yet, it seems your are quite a bit different. You can run much bigger calipers in the front versus rear on most cars, bigger rotors as well, deals with the heat better, and match up the compounds to the task.
If you still have the problem and do not want to change springs then at least some adjustable shocks could help, keep stiffening them up until the problem gets better though this is a bit of a bandaid approach.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
2027 Corvette vs The World: Every Model vs Closest Competitor
Joe Kucinski
10 Most Common Corvette Problems of the Last 20 Years!
Joe Kucinski
5 MOST and 5 LEAST Popular Corvette Model Years in History!
Joe Kucinski
2027 Corvette Buyer's Guide: Everything You Need to Know!
Joe Kucinski
10 Things C8 Corvette Owners Hate (But Won't Tell You)
Joe Kucinski
10 Best Corvettes Coming to Barrett-Jackson Palm Beach 2026!
Brett Foote
Every Corvette Grand Sport Explained! (C2, C4, C6, C7, & C8)
Joe Kucinski
Grand Sport & Grand Sport X Launch Alongside All-New 535hp LS6 V8!
Michael S. Palmer
5 Reasons Bad Drivers Crash & 5 Ways to Avoid a Costly Mistake!
Joe Kucinski
Racer
Joined: Apr 2008
Posts: 452
Likes: 8
From: Washington DC
Former Vendor
Joined: Jul 2001
Posts: 709
Likes: 3
From: Plainfield, IL
Trapp,
The differance in tire size is about 1" in diameter, so you lowered the car approximately 1/2". That can be raised up with the spring but you will need to do the rear as well or your rake will be off, assuming you went to lower profile in rear as well. Most likely your issue will be resolved with equal brake compound on rear. I always run the same compound on front and rear. GM already adjusted your brake bias.
Robert Finlayson
Performance AFX Motorsports
The differance in tire size is about 1" in diameter, so you lowered the car approximately 1/2". That can be raised up with the spring but you will need to do the rear as well or your rake will be off, assuming you went to lower profile in rear as well. Most likely your issue will be resolved with equal brake compound on rear. I always run the same compound on front and rear. GM already adjusted your brake bias.
Robert Finlayson
Performance AFX Motorsports
Thread Starter
Burning Brakes
Joined: Nov 2006
Posts: 1,098
Likes: 0
From: Yorkville IL
I would like to thank everyone for all the input on my posted question. I can always count on great advice from this forum.
Follow-up: I took the car to gingerman yesterday. I removed the front plastic air-dam...and tried some slow laps to see if I was going to 'bottom out" on the procharger intercooler craddle ski's... well I didn't. I ran harder and harder until I was full bore and NO touching to the ski's of the craddle. I am only 2 3/4 off the ground but somehow I never touched. The craddle is set-back from the front end somewhat and does not extend out near the wheel side to side so I guess I'm ok.
I will start running DTC 60's all around. That probably will help.
I would like to go to stiffer springs all-around if possible...I feel too much floating around which makes me less confident about higher speeds.
comment: This was the first time on R6's from Kumho XS's. Wow what a difference. I was so much faster through the corners..alot of fun.
thanks again
trapp
Follow-up: I took the car to gingerman yesterday. I removed the front plastic air-dam...and tried some slow laps to see if I was going to 'bottom out" on the procharger intercooler craddle ski's... well I didn't. I ran harder and harder until I was full bore and NO touching to the ski's of the craddle. I am only 2 3/4 off the ground but somehow I never touched. The craddle is set-back from the front end somewhat and does not extend out near the wheel side to side so I guess I'm ok.
I will start running DTC 60's all around. That probably will help.
I would like to go to stiffer springs all-around if possible...I feel too much floating around which makes me less confident about higher speeds.
comment: This was the first time on R6's from Kumho XS's. Wow what a difference. I was so much faster through the corners..alot of fun.
thanks again
trapp
Le Mans Master
Joined: Dec 2006
Posts: 7,251
Likes: 16
From: Phoenix Arizona
Le Mans Master
Joined: Dec 2006
Posts: 7,251
Likes: 16
From: Phoenix Arizona
I would like to thank everyone for all the input on my posted question. I can always count on great advice from this forum.
Follow-up: I took the car to gingerman yesterday. I removed the front plastic air-dam...and tried some slow laps to see if I was going to 'bottom out" on the procharger intercooler craddle ski's... well I didn't. I ran harder and harder until I was full bore and NO touching to the ski's of the craddle. I am only 2 3/4 off the ground but somehow I never touched. The craddle is set-back from the front end somewhat and does not extend out near the wheel side to side so I guess I'm ok.
I will start running DTC 60's all around. That probably will help.
I would like to go to stiffer springs all-around if possible...I feel too much floating around which makes me less confident about higher speeds.
comment: This was the first time on R6's from Kumho XS's. Wow what a difference. I was so much faster through the corners..alot of fun.
thanks again
trapp
Follow-up: I took the car to gingerman yesterday. I removed the front plastic air-dam...and tried some slow laps to see if I was going to 'bottom out" on the procharger intercooler craddle ski's... well I didn't. I ran harder and harder until I was full bore and NO touching to the ski's of the craddle. I am only 2 3/4 off the ground but somehow I never touched. The craddle is set-back from the front end somewhat and does not extend out near the wheel side to side so I guess I'm ok.
I will start running DTC 60's all around. That probably will help.
I would like to go to stiffer springs all-around if possible...I feel too much floating around which makes me less confident about higher speeds.
comment: This was the first time on R6's from Kumho XS's. Wow what a difference. I was so much faster through the corners..alot of fun.
thanks again
trapp
Thread Starter
Burning Brakes
Joined: Nov 2006
Posts: 1,098
Likes: 0
From: Yorkville IL
Sway bars and stiffer springs maybe in order..
Racer
Joined: Apr 2008
Posts: 452
Likes: 8
From: Washington DC
R compound tires are very pressure sensitive! Check your tire pressure immediately after the run to make sure you are under 40 PSI. High pressure can give you the floating effect. I should say, incorrect tire pressure in general wether it's low or high can give you that effect. It's unnerving!
Team Owner
Joined: Jul 1999
Posts: 50,808
Likes: 8
From: Buy USA products! Check the label! Employ Americans
Floating could be a mismatch of the springs and shocks due to selection or shock failure. When I had some real stiff springs and shocks that were not matched that was scary enough for me to quit after two laps and drive up the trailer.
