QA1 settings
Thread Starter
Drifting
Joined: Nov 2002
Posts: 1,905
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From: 2003 Points Champ Great Lakes Corvette Challenge; 2006/2007 Winner MSD True Street
QA1 settings
Trashing my DRM custom valved bilstiens.
qa1's will be here in a week.
I know each car is different but I am looking for a suggested setting F/R to start with. Something that works for you maybe.
Car squats almost too much on launch now. I raised the rear leaf and an inch and a half already.
My 60 ft now are 1.54 on a good day.
I pull the skinnies off the ground a tad when I launch now.
Hope this helps with your suggestions as to where my car is at now and to which settings I should start with before tuning them in.
Thanks!
Matt383
qa1's will be here in a week.
I know each car is different but I am looking for a suggested setting F/R to start with. Something that works for you maybe.
Car squats almost too much on launch now. I raised the rear leaf and an inch and a half already.
My 60 ft now are 1.54 on a good day.
I pull the skinnies off the ground a tad when I launch now.
Hope this helps with your suggestions as to where my car is at now and to which settings I should start with before tuning them in.
Thanks!
Matt383
Thread Starter
Drifting
Joined: Nov 2002
Posts: 1,905
Likes: 1
From: 2003 Points Champ Great Lakes Corvette Challenge; 2006/2007 Winner MSD True Street
How about the fronts.??
I am getting dual adjustables by the way, so they have different settings for compression and release.
So that would be 10-12 clicks for the "down" force resistance how about the "Up" force?
That's the quandary.
Matt383
Thread Starter
Drifting
Joined: Nov 2002
Posts: 1,905
Likes: 1
From: 2003 Points Champ Great Lakes Corvette Challenge; 2006/2007 Winner MSD True Street
But I still have the question about the dual adjustables.
There are two settings for each shock.
Compression and rebound.
Would that setting be 2 for the compression or rebound or both?
Matt383
Team Owner
Joined: Jul 2001
Posts: 182,997
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From: Lakeland, FL
Cruise-In IV-V-VI-VII-VIII Veteran
St. Jude Donor '03, '06, '17
The 10 - 12 clicks is for the down and up force... On IRS cars, you want to have as little travel in the rear as the geometry gets messed up when the car is squatting too much. The most important resistance is the rebound setting (expansion) as a too quick rebound in the rear makes the front come down too quickly.. Slow compression and slow rebound is the ideal for a IRS car.
I went through a long learning process with my setup.. People would call my car the dolphin because the front would be sooo bouncy. I thought that it was caused by the front suspension but it was caused by the rear suspension being too soft.
Team Owner
Joined: Jul 2001
Posts: 182,997
Likes: 88
From: Lakeland, FL
Cruise-In IV-V-VI-VII-VIII Veteran
St. Jude Donor '03, '06, '17
Edgar, your problem is not in the front. Watch the video of your transbrake launch.. The moment the rear rebounds, the front gets forced down and that causes the bounce. I had exactly the same problem and going stiffer in the rear fixed it...
Thread Starter
Drifting
Joined: Nov 2002
Posts: 1,905
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From: 2003 Points Champ Great Lakes Corvette Challenge; 2006/2007 Winner MSD True Street
I use competition engineering adjustable 90/10's in front and they work great (90/10 setting).. They can be adjusted 90/10, 80/20 and 60/40..
The 10 - 12 clicks is for the down and up force... On IRS cars, you want to have as little travel in the rear as the geometry gets messed up when the car is squatting too much. The most important resistance is the rebound setting (expansion) as a too quick rebound in the rear makes the front come down too quickly.. Slow compression and slow rebound is the ideal for a IRS car.
I went through a long learning process with my setup.. People would call my car the dolphin because the front would be sooo bouncy. I thought that it was caused by the front suspension but it was caused by the rear suspension being too soft.
The 10 - 12 clicks is for the down and up force... On IRS cars, you want to have as little travel in the rear as the geometry gets messed up when the car is squatting too much. The most important resistance is the rebound setting (expansion) as a too quick rebound in the rear makes the front come down too quickly.. Slow compression and slow rebound is the ideal for a IRS car.
I went through a long learning process with my setup.. People would call my car the dolphin because the front would be sooo bouncy. I thought that it was caused by the front suspension but it was caused by the rear suspension being too soft.
My car does squat too much now.
It slams the half shaft loops with the underbody which pushed them to rub against the half shafts.
Fronts = 90 down 10 up? or the other way around?
Rear = max(90?) down and up.
Do I have that right?
Thanks
Matt383
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Team Owner
Joined: Jul 2001
Posts: 182,997
Likes: 88
From: Lakeland, FL
Cruise-In IV-V-VI-VII-VIII Veteran
St. Jude Donor '03, '06, '17
Thanks for the clarification.
My car does squat too much now.
It slams the half shaft loops with the underbody which pushed them to rub against the half shafts.
Fronts = 90 down 10 up? or the other way around?
Rear = max(90?) down and up.
Do I have that right?
Thanks
Matt383
My car does squat too much now.
It slams the half shaft loops with the underbody which pushed them to rub against the half shafts.
Fronts = 90 down 10 up? or the other way around?
Rear = max(90?) down and up.
Do I have that right?
Thanks
Matt383
In the rear, ideally you want a 50/50 distribution of very tight compression... A tighter spring will also help a lot in combination with a very tight shock setting..
A tight rear shock/spring setting causes the weight to be directly forced onto the tires. If the rear suspension compresses, force to the tires is actually reduced as the suspension absorbs part of the down force. The concept for a solid axle car is completely different but for IRS cars, you want the rear as stiff as possible.
Look at the slow motion launch. There's no noticeable movement in the rear. (it actually compresses by 1 inch (visible on the shock) but that's about it
Thread Starter
Drifting
Joined: Nov 2002
Posts: 1,905
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From: 2003 Points Champ Great Lakes Corvette Challenge; 2006/2007 Winner MSD True Street
Thanks.
I needed the clarification between the set up for solid and IRS.
That explains a lot!
I assume that solid cars want to have a softer set up up in the rear than IRS.
Do you think I should get a stiffer spring now too?
I suppose I should try one thing at a time as the saying goes then I know what effect each has.....
Matt383
I needed the clarification between the set up for solid and IRS.
That explains a lot!
I assume that solid cars want to have a softer set up up in the rear than IRS.
Do you think I should get a stiffer spring now too?
I suppose I should try one thing at a time as the saying goes then I know what effect each has.....
Matt383
Team Owner
Joined: Jul 2001
Posts: 182,997
Likes: 88
From: Lakeland, FL
Cruise-In IV-V-VI-VII-VIII Veteran
St. Jude Donor '03, '06, '17
Thanks.
I needed the clarification between the set up for solid and IRS.
That explains a lot!
I assume that solid cars want to have a softer set up up in the rear than IRS.
Do you think I should get a stiffer spring now too?
I suppose I should try one thing at a time as the saying goes then I know what effect each has.....
Matt383
I needed the clarification between the set up for solid and IRS.
That explains a lot!
I assume that solid cars want to have a softer set up up in the rear than IRS.
Do you think I should get a stiffer spring now too?
I suppose I should try one thing at a time as the saying goes then I know what effect each has.....
Matt383
What I would do if I was you would be to first try to go with a very tight setting for your QA1's in the rear and see how the car reacts.
Mark the tire with shoe polish and have someone videotape one of your launches with the camera pointed at the rear tire (that the shoe polish mark is visible).
Try to do a slow motion analysis of front and rear suspension travel. (watch what the front suspension does when the rear suspension rebounds). I'd also mark the shocks to see how much rear end travel you get. (you can use a black marker etc.). I put some grease on mine and I can see how much the shock compresses by looking at how far the grease was moved down. You really don't want more than 1 inch travel in the rear..
Thread Starter
Drifting
Joined: Nov 2002
Posts: 1,905
Likes: 1
From: 2003 Points Champ Great Lakes Corvette Challenge; 2006/2007 Winner MSD True Street
Team Owner
Joined: Jul 2001
Posts: 182,997
Likes: 88
From: Lakeland, FL
Cruise-In IV-V-VI-VII-VIII Veteran
St. Jude Donor '03, '06, '17
Well, I also switched from wrinkle wall to radial slicks but suspension tuning has made a significant difference..
Le Mans Master
Joined: Feb 1999
Posts: 6,172
Likes: 11
From: somers, ny
Matt, your car sounds similar to mine. While the double adustables are nice to have, i dont think they are necessary with our C4 suspensions. As Oliver said, you want the rear to be stiff and you also don't want it to squat too hard. So a stiff spring/shock combo works well. I've got my Qa1 set at 6 clicks (midpoint) and usually dont vary it more than 2 clicks (although after seeing Olivers launch i might try 10-12 clicks in the rear). I see you've already raised the rear...I also use long bump stops in the rear so it can only squat so far. If the rear shocks are too loose, i can feel it hit the stop, but with them stiff, it just touchs the stop. In the front you want it as loose as possible without losing control or bouncing down the track. The front uspension in most C4s is inherently stiff, so i set my shocks to zero. QA1 also makes a drag version single adjustable that is stiffer on compresion (similar to a 90/10). That shock might be a little harsh on the street when tightened, but they work great at the strip.
Last edited by ralph; Feb 28, 2007 at 01:58 PM.
Team Owner
Joined: Jul 2001
Posts: 182,997
Likes: 88
From: Lakeland, FL
Cruise-In IV-V-VI-VII-VIII Veteran
St. Jude Donor '03, '06, '17
Matt, your car sounds similar to mine. While the double adustables are nice to have, i dont think they are necessary with our C4 suspensions. As Oliver said, you want the rear to be stiff and you also don't want it to squat too hard. So a stiff spring/shock combo works well. I've got my Qa1 set at 6 clicks (midpoint) and usually dont vary it more than 2 clicks (although after seeing Olivers launch i might try 10-12 clicks in the rear). I see you've already raised the rear...I also use long bump stops in the rear so it can only squat so far. If the rear shocks are too loose, i can feel it hit the stop, but with them stiff, it just touchs the stop. In the front you want it as loose as possible without losing control or bouncing down the track. The front uspension in most C4s is inherently stiff, so i set my shocks to zero. QA1 also makes a drag version single adjustable that is stiffer on compresion (similar to a 90/10). That shock might be a little harsh on the street when tightened, but they work great at the strip.
Thread Starter
Drifting
Joined: Nov 2002
Posts: 1,905
Likes: 1
From: 2003 Points Champ Great Lakes Corvette Challenge; 2006/2007 Winner MSD True Street
Matt, your car sounds similar to mine. While the double adustables are nice to have, i dont think they are necessary with our C4 suspensions. As Oliver said, you want the rear to be stiff and you also don't want it to squat too hard. So a stiff spring/shock combo works well. I've got my Qa1 set at 6 clicks (midpoint) and usually dont vary it more than 2 clicks (although after seeing Olivers launch i might try 10-12 clicks in the rear). I see you've already raised the rear...I also use long bump stops in the rear so it can only squat so far. If the rear shocks are too loose, i can feel it hit the stop, but with them stiff, it just touchs the stop. In the front you want it as loose as possible without losing control or bouncing down the track. The front uspension in most C4s is inherently stiff, so i set my shocks to zero. QA1 also makes a drag version single adjustable that is stiffer on compresion (similar to a 90/10). That shock might be a little harsh on the street when tightened, but they work great at the strip.
We did talk to Qa1 tech and they don't make a Drag shock to fit my 88 vette. They said to use the dual adjustables.
Thanks for the stop suggestion...
Matt383