[Z06] Preventing Breakage--Driver Errors to Avoid
Racer
Joined: Dec 2006
Posts: 4,434
Likes: 18
From: Braselton GA
Ranger, have followed a of your posts. Have done a lot of drag racing in other cars, but am reasonbly new to the Z/C5 set up.
I'm a track junkie (road racing) but am probably one of the few who do that, that enjoy some gear banging as well.
Looking to get an extra set of rears for strip work (local drags is 20 mins away).
What's your recommendation, MT's 275/40/17 (on front C5Z rims), BFG 275/40/17, or BFG's other DR which has an exact C5 rear size, 295/35/18?
Every car I've ever ran always does better with more sidewall (less hop, more straight line stick), so I'm inclined to give up a tick of width for a smaller dia (17") wheel with more sidewall on the tire.
Not looking for totally bonsai launches for now, just something I can be reasonably aggressive with and have it stick through 1-2 without spinning/hopping (my F1's are OEM 01, 6+ yr old now). Which tire (MT or BFG) do you think is easier on the driveline (softer sidewall?) Which is stickier?
thanks
I'm a track junkie (road racing) but am probably one of the few who do that, that enjoy some gear banging as well.
Looking to get an extra set of rears for strip work (local drags is 20 mins away).
What's your recommendation, MT's 275/40/17 (on front C5Z rims), BFG 275/40/17, or BFG's other DR which has an exact C5 rear size, 295/35/18?
Every car I've ever ran always does better with more sidewall (less hop, more straight line stick), so I'm inclined to give up a tick of width for a smaller dia (17") wheel with more sidewall on the tire.
Not looking for totally bonsai launches for now, just something I can be reasonably aggressive with and have it stick through 1-2 without spinning/hopping (my F1's are OEM 01, 6+ yr old now). Which tire (MT or BFG) do you think is easier on the driveline (softer sidewall?) Which is stickier?
thanks
Thread Starter
Race Director
Joined: Aug 2000
Posts: 10,649
Likes: 31
From: Central Florida
^^^ Hi drivinhard. The best options are
(1) BFG 315.35.17
Required launch rpm of 3600-4200 at 18 psi
(2) MT ET Street Radials 275.40.17
Required launch rpm of 4600-5200 at 20-22 psi
Both tires will fit on C5Z front wheels 17" x 9.5". I use this wheel with those BFGs on my C6Z now.
The MT will produce a little more consistent 60' and 330' with more in the 1.6x and sub-5.0. But the higher launch rpm put more wear on the clutch.
Ranger
(1) BFG 315.35.17
Required launch rpm of 3600-4200 at 18 psi
(2) MT ET Street Radials 275.40.17
Required launch rpm of 4600-5200 at 20-22 psi
Both tires will fit on C5Z front wheels 17" x 9.5". I use this wheel with those BFGs on my C6Z now.
The MT will produce a little more consistent 60' and 330' with more in the 1.6x and sub-5.0. But the higher launch rpm put more wear on the clutch.
Ranger
Burning Brakes
Joined: Sep 2002
Posts: 1,077
Likes: 1
From: Greenville SC
I have a stock 02 Z (04 shocks).
99% of my high performance driving is on a roadcourse, but once in a great while I will get on it on the street for a couple of gears.
Question:
Are 2 hops reason enough to get off the gas on the 1-2 shift? That is usualy what my car does. It spins the tires in first (goosing it from a roll) and hops 2-3 times on the 1-2 shift (no power shift, just speed shift) then catches and goes.
Any harm in this?
Thanks,
MD
99% of my high performance driving is on a roadcourse, but once in a great while I will get on it on the street for a couple of gears.
Question:
Are 2 hops reason enough to get off the gas on the 1-2 shift? That is usualy what my car does. It spins the tires in first (goosing it from a roll) and hops 2-3 times on the 1-2 shift (no power shift, just speed shift) then catches and goes.
Any harm in this?
Thanks,
MD
Thread Starter
Race Director
Joined: Aug 2000
Posts: 10,649
Likes: 31
From: Central Florida
I have a stock 02 Z (04 shocks).
Question:
Are 2 hops reason enough to get off the gas on the 1-2 shift? That is usualy what my car does. It spins the tires in first (goosing it from a roll) and hops 2-3 times on the 1-2 shift (no power shift, just speed shift) then catches and goes.
Any harm in this?
Question:
Are 2 hops reason enough to get off the gas on the 1-2 shift? That is usualy what my car does. It spins the tires in first (goosing it from a roll) and hops 2-3 times on the 1-2 shift (no power shift, just speed shift) then catches and goes.
Any harm in this?
At stock and near-stock power levels, the C5 axles and rear are stout.
If the rear were to start hopping, continue to hop, and you stay on the throttle, that would be risky. Two-three hops and go, not unusual.
Ranger
Safety Car
Joined: Jun 2004
Posts: 4,921
Likes: 1
From: Minburn Ia
Nice thread Ranger ....
When you get tired of your day job ..... Open up RANGER'S 1/4 Mile School.
Do summer road tours in your Z ... visiting vette clubs, instructing @ club events / track rentals, and selling DVD's to all on hand.
Chevy/Goodyear ought to sponsor you ... and provide you new Z/tires on yearly basis
In return you provide them with 'official' performance #'s ... on each current/future generation of vettes.
When you get tired of your day job ..... Open up RANGER'S 1/4 Mile School.
Do summer road tours in your Z ... visiting vette clubs, instructing @ club events / track rentals, and selling DVD's to all on hand.
Chevy/Goodyear ought to sponsor you ... and provide you new Z/tires on yearly basis
In return you provide them with 'official' performance #'s ... on each current/future generation of vettes.
Thread Starter
Race Director
Joined: Aug 2000
Posts: 10,649
Likes: 31
From: Central Florida
Nice thread Ranger ....
When you get tired of your day job ..... Open up RANGER'S 1/4 Mile School.
Do summer road tours in your Z ... visiting vette clubs, instructing @ club events / track rentals, and selling DVD's to all on hand.
Chevy/Goodyear ought to sponsor you ... and provide you new Z/tires on yearly basis
In return you provide them with 'official' performance #'s ... on each current/future generation of vettes.
When you get tired of your day job ..... Open up RANGER'S 1/4 Mile School.
Do summer road tours in your Z ... visiting vette clubs, instructing @ club events / track rentals, and selling DVD's to all on hand.
Chevy/Goodyear ought to sponsor you ... and provide you new Z/tires on yearly basis
In return you provide them with 'official' performance #'s ... on each current/future generation of vettes.
Ranger
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Thread Starter
Race Director
Joined: Aug 2000
Posts: 10,649
Likes: 31
From: Central Florida
Every time you add fuel, check the fluid in the reservoir. If it's not clear and pale color, follow the fluid changing protocol in brief in Post #28.
It's never too late to start this as a preventive measure for avoiding pedal woes and consequential tranny issues.
Ranger
It's never too late to start this as a preventive measure for avoiding pedal woes and consequential tranny issues.
Ranger
Burning Brakes
Joined: Sep 2002
Posts: 1,077
Likes: 1
From: Greenville SC
I know what you are talking about. The only time I took my car to the drag racing track it was 45 or so degrees (dead of winter here in South Florida) I couldn't get the stock F1s to stop severely hopping, so I aborted the mission entirely and parked the car. From what you are saying, sounds like I made a good decision...
MD
Burning Brakes
Joined: Oct 2004
Posts: 924
Likes: 0
From: Calgary
I know you've already answered this one for me in the past Ranger, however I must confess, I've forgotten the answer! :bb
Thanks again!
Thread Starter
Race Director
Joined: Aug 2000
Posts: 10,649
Likes: 31
From: Central Florida
Is that when you do a burnout, then get off the gas but leave the transmission engaged in gear, so that the tires slow down, and eventually catch traction and launch you forward towards the staging line?
I know you've already answered this one for me in the past Ranger, however I must confess, I've forgotten the answer! :bb
Thanks again!
I know you've already answered this one for me in the past Ranger, however I must confess, I've forgotten the answer! :bb
Thanks again!
The driving error occurs when, instead, the driver then rehammers the throttle several times on the way to the line, "testing the tires' hook." The on-and-off power depleat the heat in the tires and risk damage to the drive train. Dry-hopping to the line has all risk, no benefit.
Ranger
Safety Car
Joined: Apr 2003
Posts: 4,306
Likes: 772
From: Long Island NY
Why would it be hard on the rear if hammering a 1-2 shift on cold streets/tires? That just means the tires are going to spin. Correct me if I am wrong but I've always known it be hard on the rear when the tires hook and the full force goes into the rear, instead of being spun away with the tires spinning.
Thread Starter
Race Director
Joined: Aug 2000
Posts: 10,649
Likes: 31
From: Central Florida
Why would it be hard on the rear if hammering a 1-2 shift on cold streets/tires? That just means the tires are going to spin. Correct me if I am wrong but I've always known it be hard on the rear when the tires hook and the full force goes into the rear, instead of being spun away with the tires spinning.
C5Z was engineered end-to-end to handle stock power plus about 10%. Your 450-500 is way beyond that.
Likelihood of breakage will depend entirely on your driving venues, habits and techniques. Brutal techniques can break axles, clutch and tranny, most commonly. Smooth driving and avoiding launches at the drag strip, you may never see breakage until hammering a 1-2 shift on the wrong surface or cold streets/tires.
Most racers at your power-level harden the rear-end and change to an after-market clutch. If/when the tranny goes, they harden and micro-polish key components during the rebuild...
Likelihood of breakage will depend entirely on your driving venues, habits and techniques. Brutal techniques can break axles, clutch and tranny, most commonly. Smooth driving and avoiding launches at the drag strip, you may never see breakage until hammering a 1-2 shift on the wrong surface or cold streets/tires.
Most racers at your power-level harden the rear-end and change to an after-market clutch. If/when the tranny goes, they harden and micro-polish key components during the rebuild...
As to wrong surface, new concrete with a textured surface has big grip. Put one wheel on that concrete and the other on blacktop (eg, transitioning from the shoulder to the roadway) and then hammer the throttle to accelerate...snap an axle. Guy in our club did just that.
If anyone bumps the power of a Corvette more than 8-10% the risk of breakage goes up enormously. The drive train simply isn't engineered for the additional stress.
At the drag strip on both stock tires and drag radials at stock power levels, I've dead hooked my C5Z and C6Z many times without breaking the rear. But it's something I'd try harder to avoid if I had 20-25% rwhp via engine mods and hadn't hardened the drive train.
Hope that clears it up a bit.
Ranger
Last edited by Ranger; Apr 16, 2007 at 07:16 PM.
Safety Car
Joined: Apr 2003
Posts: 4,306
Likes: 772
From: Long Island NY
I'd still expect Wheel hop would be less likely to happen on cold streets/tires than warm ones, but I guess the difference lies in the fact that you are refering to DR's.
From my experiences with the stock GY SC's, a hard 1-2 shift on cold streets/tires only ever equals spin, spin, spin. If its warm outside but the tires aren't "heated up", than my tires will try to catch and thats when I get wheel hop sometimes. My tires have no prayer at catching the pavement enough to even muster a wheel hop in the cold at stock 01 Z06 power levels. My SC's are useless in the cold, spining hard in the 2-3 shift, let alone the 1-2 shift, and even a little spin in the 3-4 shift sometimes.
I guess the DR's semi-hook in the cold causing the wheel hop, whereas they just fully hook and go in the warm, and thats what you mean.
From my experiences with the stock GY SC's, a hard 1-2 shift on cold streets/tires only ever equals spin, spin, spin. If its warm outside but the tires aren't "heated up", than my tires will try to catch and thats when I get wheel hop sometimes. My tires have no prayer at catching the pavement enough to even muster a wheel hop in the cold at stock 01 Z06 power levels. My SC's are useless in the cold, spining hard in the 2-3 shift, let alone the 1-2 shift, and even a little spin in the 3-4 shift sometimes.
I guess the DR's semi-hook in the cold causing the wheel hop, whereas they just fully hook and go in the warm, and thats what you mean.
Safety Car
Joined: Jul 2006
Posts: 4,647
Likes: 1
From: Objects in your mirror are losing , Long Island, NY
St. Jude Donor '08
With racing season upon us, here are some tips...driver errors to avoid.
I had 500+ passes in two stock Z06s and never broke anything.
But here are some ways folks break them....
(1) Get the rear wheels hopping on launch or the 1-2 shift and then stay on the throttle. Great way to break an axle or the diff case.
(2) Heat the tires at the drags and then dry hop it up to the line. Another great way to break an axle or the diff case.
(3) Burnout dry tires at the drags. More torture for the rear.
(4) Try to heat the tires at the drags, botch it, then try it again without reapplying water to the rear tires. This glazes the clutch or break the rear.
(5) Mod the motor to above 390 rwhp and then do hard launches at the drags on DRs. The rear will hate that.
And I'll throw in two for the tranny:
(6) Brutalize the tranny with poorly timed shifts near the redline.
(7) Fail to follow the clutch fluid maintenance protocol; get the pedal woes and do strong shifts anyway.
Now, if you avoid the (1)-(7) driving errors, then you can probably make 500+ passes without breakage...like I did.
Here is a link to a write-up that may be helpful in improving performance: C5Z06 Launch Techniques
Ranger
I had 500+ passes in two stock Z06s and never broke anything.
But here are some ways folks break them....
(1) Get the rear wheels hopping on launch or the 1-2 shift and then stay on the throttle. Great way to break an axle or the diff case.
(2) Heat the tires at the drags and then dry hop it up to the line. Another great way to break an axle or the diff case.
(3) Burnout dry tires at the drags. More torture for the rear.
(4) Try to heat the tires at the drags, botch it, then try it again without reapplying water to the rear tires. This glazes the clutch or break the rear.
(5) Mod the motor to above 390 rwhp and then do hard launches at the drags on DRs. The rear will hate that.
And I'll throw in two for the tranny:
(6) Brutalize the tranny with poorly timed shifts near the redline.
(7) Fail to follow the clutch fluid maintenance protocol; get the pedal woes and do strong shifts anyway.
Now, if you avoid the (1)-(7) driving errors, then you can probably make 500+ passes without breakage...like I did.
Here is a link to a write-up that may be helpful in improving performance: C5Z06 Launch Techniques
Ranger
Le Mans Master
Joined: Oct 2000
Posts: 5,474
Likes: 80
From: raleigh, nc
good info.. Wish I reread this a couple of days ago... I went to the track and put only 20 pounds in the runflats. Was it really that bad I went down that low, because Ranger recommended only go down to 26lbs or so..
