Road racing likes stiff front suspension. Drag racing seems to like soft front suspension.
So which hurts more. Slow time in the autocross or slow time drag racing?
I've gamed this out six ways from Sunday and while I could switch springs between events the diameter of the springs used don't give me any options for softer. I could buy a pair of different diameter springs and adapt them but then not be able to reverse into road racing springs.
Now if the weight transfer soft springs afford isn't a big advantage I'll trade the disadvantage in drag racing for the advantage on the Autocross
Not knowing what car . . . what about a whole strut/spring package for each type of event?
Green Miata is an autocross car. It did a 1.89 60 foot. You can't generalize and say a handling setup can't drag.
Just as a generalization, my thinking would be that a good handling suspension will hurt 1/4 mile times much less than a drag suspension would hurt autocross
60 foot will suffer with stiff suspension, but the front is less important than the rear.
Stampie (FS) said:
Green Miata is an autocross car. It did a 1.89 60 foot. You can't generalize and say a handling setup can't drag.
I don't know anything about either drag racing or autocross. ( I'm a road racer) Is that a good thing or not?
03Panther said:
Just as a generalization, my thinking would be that a good handling suspension will hurt 1/4 mile times much less than a drag suspension would hurt autocross
Just a general observation but I noticed all front engine rear drive drag racers seem to lift the front end up to transfer weight to the rear wheels.
On the other hand just watching a few fast cars in autocross the front end stays pretty flat with an absolute minimum of body roll.
L5wolvesf said:
Not knowing what car . . . what about a whole strut/spring package for each type of event?
Not possible for me to change the whole front suspension around. In my younger days it was nothing to pull an all nighter. But that's not possible anymore.
frenchyd said:
Just a general observation but I noticed all front engine rear drive drag racers seem to lift the front end up to transfer weight to the rear wheels.
On the other hand just watching a few fast cars in autocross the front end stays pretty flat with an absolute minimum of body roll.
That’s the observation that I assume initiated the question, since that implies opposite types of suspension
i take the question to be what direction should the compromise be in.
I think the “soft” (to simplify) will hurt the handling more than the other way around
i would also (generalizing again) think that road racing experience would translate to auto x more so than drag racing would relate to auto x
Rodan
Dork
2/21/21 12:38 a.m.
Front suspension optimized for drag racing will have very little rebound damping to allow quick extension, which creates weight transfer to the rear for traction. It's not so much about being 'soft', but getting good extension, and then the suspension is controlled in compression to allow it to settle without oscillation.
As noted, the 'penalty' for road race suspension on the dragstrip is probably less than the 'penalty' for drag suspension on the AutoX course.
JBinMD
New Reader
2/21/21 1:46 a.m.
frenchyd said:
Stampie (FS) said:
Green Miata is an autocross car. It did a 1.89 60 foot. You can't generalize and say a handling setup can't drag.
I don't know anything about either drag racing or autocross. ( I'm a road racer) Is that a good thing or not?
IMHO auto-x IS a form of road racing. Just, you know, a very short, very slow version of road racing. 
(don't attack me for that, just sayin)
A couple of thoughts:
1) While a stiff auto-x suspension will hurt you some at the drag strip, that's mostly at the launch, but not nearly as much beyond 100' or so or after you upshift. That said, a soft, wallowy drag setup will hurt you all over an auto-x course, so unless the situation is either one where the drag race scoring is weighted unusually high or the auto-x course has a point-and-shoot layout that favors muscle cars, you are probably better off tuning your suspension more towards the auto-x end of the spectrum.
2) Since a stiff front sway bar isn't nearly as much of a deficit at the drags as stiff front springs are, you could use somewhat softer front springs with a somewhat stiffer front ARB to achieve the same front roll stiffness without as much of a penalty at launch. Also, using adjustable dampers should help quite a bit to tune the suspension differently for the two events.
In reply to frenchyd :
For a 14 second car that's pretty good. You might want to just plug some numbers into an online calculator and get and idea of what times look like. Realize that they tend to be optimistic.
Instead of worrying about springs, just leave them stiff, it might be better to swap shocks.
I don't know what kind of car the OP is running but stiff shocks for autox and then something with soft rebound front and soft bound rear would probably get you 80% of the benefit of a dedicated drag setup.
This is, of course, only practical if your platform mounts shocks separated from the springs.
03Panther said:
frenchyd said:
Just a general observation but I noticed all front engine rear drive drag racers seem to lift the front end up to transfer weight to the rear wheels.
On the other hand just watching a few fast cars in autocross the front end stays pretty flat with an absolute minimum of body roll.
That’s the observation that I assume initiated the question, since that implies opposite types of suspension
i take the question to be what direction should the compromise be in.
I think the “soft” (to simplify) will hurt the handling more than the other way around
i would also (generalizing again) think that road racing experience would translate to auto x more so than drag racing would relate to auto x
That's remarkably astute of you. My one drag racing experience showed me quick reaction time was everything. Where as my one autocross showed me smoothness was critical.
Road racing is more about finding the edge and not going over it. The edge of acceleration so you don't blow off traction. The edge of braking so you aren't locking up. The edge of cornering so you aren't slowing down to catch the car.
DaewooOfDeath said:
Instead of worrying about springs, just leave them stiff, it might be better to swap shocks.
I don't know what kind of car the OP is running but stiff shocks for autox and then something with soft rebound front and soft bound rear would probably get you 80% of the benefit of a dedicated drag setup.
This is, of course, only practical if your platform mounts shocks separated from the springs.
A 90/10 shock for drag racing and a 50/50 shock for road racing is actually swap able between events. Now to find a 90/10 shock that will fit on or can be adapted to a Jaguar.
I wonder if there is a way to convert a regular shock to a 90/10 or heck a 100/0? A one way check valve. But how would I insert it?
JBinMD said:
frenchyd said:
Stampie (FS) said:
Green Miata is an autocross car. It did a 1.89 60 foot. You can't generalize and say a handling setup can't drag.
I don't know anything about either drag racing or autocross. ( I'm a road racer) Is that a good thing or not?
IMHO auto-x IS a form of road racing. Just, you know, a very short, very slow version of road racing. (don't attack me for that, just sayin)
A couple of thoughts:
1) While a stiff auto-x suspension will hurt you some at the drag strip, that's mostly at the launch, but not nearly as much beyond 100' or so or after you upshift. That said, a soft, wallowy drag setup will hurt you all over an auto-x course, so unless the situation is either one where the drag race scoring is weighted unusually high or the auto-x course has a point-and-shoot layout that favors muscle cars, you are probably better off tuning your suspension more towards the auto-x end of the spectrum.
2) Since a stiff front sway bar isn't nearly as much of a deficit at the drags as stiff front springs are, you could use somewhat softer front springs with a somewhat stiffer front ARB to achieve the same front roll stiffness without as much of a penalty at launch. Also, using adjustable dampers should help quite a bit to tune the suspension differently for the two events.
Very valid point. A comment, I don't know how valid. but in the Bahama's neither I or Sir Sterling Moss had ever done one. I saw him attack it like a extremely short coarse road race. I knew with fresh tires on and his more powerful engine he would probably beat me . So instead I determined to attempt to be smooth and I actually beat him!!!!!
I don't know if it's the right approach. But it's what I'm going to try.
This will be a local version of the challenge so I won't have access to the "pros" but maybe I can find a local driver who's pretty good?
If you run a shock with adjustable rebound, just crank the front rebound down before the drags. It won't get you as far as a proper drag suspension, but depending the car, power level, and tires, it'll probably get you close. And as others have said, the wrong suspension will hurt far less on the drag strip than for autocross.
frenchyd said:
DaewooOfDeath said:
Instead of worrying about springs, just leave them stiff, it might be better to swap shocks.
I don't know what kind of car the OP is running but stiff shocks for autox and then something with soft rebound front and soft bound rear would probably get you 80% of the benefit of a dedicated drag setup.
This is, of course, only practical if your platform mounts shocks separated from the springs.
A 90/10 shock for drag racing and a 50/50 shock for road racing is actually swap able between events. Now to find a 90/10 shock that will fit on or can be adapted to a Jaguar.
I wonder if there is a way to convert a regular shock to a 90/10 or heck a 100/0? A one way check valve. But how would I insert it?
Lots of people sell used drag racing shocks. I can't imagine welding on a couple tabs to adapt whatever's cheap to your stock control arms would be that difficult. It doesn't need to be a direct replacement for the regular/autox stuff or to mount in the same place.
frenchyd said:
Stampie (FS) said:
Green Miata is an autocross car. It did a 1.89 60 foot. You can't generalize and say a handling setup can't drag.
I don't know anything about either drag racing or autocross. ( I'm a road racer) Is that a good thing or not?
It's not bad, but good drag cars will 60' in the 1.3-1.4 second range.
Most of a quarter mile ET is made up in the first sixty feet, so this is critical.
Pete. (l33t FS) said:
frenchyd said:
Stampie (FS) said:
Green Miata is an autocross car. It did a 1.89 60 foot. You can't generalize and say a handling setup can't drag.
I don't know anything about either drag racing or autocross. ( I'm a road racer) Is that a good thing or not?
It's not bad, but good drag cars will 60' in the 1.3-1.4 second range.
Most of a quarter mile ET is made up in the first sixty feet, so this is critical.
My 82 Camaro is a super-not drag car. Big springs, big bars, bad instant center, old Kuhmo 712s, 2.6 second 60 foot, 13.50s around 104 mph. I figure suspension and tires has it in the 12s, but then it wouldn't be as much fun to drive.
Plus I'm cheap and lazy.
Edit: My new phone is not a car guy phone. It corrects Camaro to Cameron. Not cool, Samsung.
Pete. (l33t FS) said:
frenchyd said:
Stampie (FS) said:
Green Miata is an autocross car. It did a 1.89 60 foot. You can't generalize and say a handling setup can't drag.
I don't know anything about either drag racing or autocross. ( I'm a road racer) Is that a good thing or not?
It's not bad, but good drag cars will 60' in the 1.3-1.4 second range.
Most of a quarter mile ET is made up in the first sixty feet, so this is critical.
I hope this really isn't stupid, but wouldn't power and traction affect the 60 ft times too? Or is it all reaction and traction?
DaewooOfDeath said:
frenchyd said:
DaewooOfDeath said:
Instead of worrying about springs, just leave them stiff, it might be better to swap shocks.
I don't know what kind of car the OP is running but stiff shocks for autox and then something with soft rebound front and soft bound rear would probably get you 80% of the benefit of a dedicated drag setup.
This is, of course, only practical if your platform mounts shocks separated from the springs.
A 90/10 shock for drag racing and a 50/50 shock for road racing is actually swap able between events. Now to find a 90/10 shock that will fit on or can be adapted to a Jaguar.
I wonder if there is a way to convert a regular shock to a 90/10 or heck a 100/0? A one way check valve. But how would I insert it?
Lots of people sell used drag racing shocks. I can't imagine welding on a couple tabs to adapt whatever's cheap to your stock control arms would be that difficult. It doesn't need to be a direct replacement for the regular/autox stuff or to mount in the same place.
Excellent point. I can pull one set of shocks and find something with a similar stroke and adapt it. Plus rumor has it there are probably a lot of Chevy's that have used drag racing slicks for sale. ( those bolt right on Jaguars)
frenchyd said:
I hope this really isn't stupid, but wouldn't power and traction affect the 60 ft times too? Or is it all reaction and traction?
Power does impact 60 foot times, but making good use of the tires makes a bigger difference. Getting weight onto the tires, loading them up enough at launch (appropriate launch RPM with a manual or appropriate converter choice with an auto) and related factors all have a huge impact. There's no magic formula for a lot of it though, as different chassis and tires will have different needs as far as suspension and drivetrain to use the tires to the best of their ability.
In reply to rslifkin :
The Turbo 400 transmission is there a smaller torque converter with a higher stall speed that just bolts on?
Rodan
Dork
2/21/21 10:32 a.m.
Are you running single passes for time, or actually racing against the other car?
A quick reaction time will often win a close drag race, but it has ZERO effect on the elapsed time of the run. Reaction time is a measurement of how well you time the car's start (when the wheels break the timing light beam) to the green light. Hint: if you wait for the green light, you're already too late. If you're just running a pass for time, you can forget about reaction time.
60 foot time is all about how hard the car launches, which means it's all about traction. Get the max amount of power to the drive wheels and keep it there.
