Car Squatting at Launch

S

SCrazy

SCCoA Member
Alot of the stock suspension cars really squat at launch, mine is pretty extreme. I have vogtland springs and Koni shocks that are adjusted full firm but the car still rotates alot on launch.

Is there something short of new springs & shocks that can be done to get this under control?
 
SCrazy said:
Alot of the stock suspension cars really squat at launch, mine is pretty extreme. I have vogtland springs and Koni shocks that are adjusted full firm but the car still rotates alot on launch.

Is there something short of new springs & shocks that can be done to get this under control?
Click to expand...

drop it off at my place after the shootout and it will quit doing that
 
The attached picture is typical of what I'm talking about....looks as though the rear suspension is bottoming out. I don't think the wheels bounce, I've not felt that anyway, and unfortunately I don't have a video that shows a good view of the launch.

Front and rear shocks are all set firm now although I think in this pic fronts were pretty soft.

Bushings have all been changed...MN12 performance kit from a few years ago

Somehow I knew Kevin's "ulimate" solution would rear it's head...someday maybe!!

Airbags??? Can I just chuck a couple of air bags in there and make this better?
 

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Mine does the same thing. Stock suspension all around.

That is a great picture Brian.

Ira
 
about a month ago when I took my black car to the track it was doing the same thing, rebuilt stock but upgraded bushings...now my red car which is lowered 1.6in not so much. Suggest lowering with proper lowering springs...casue when I bought my red car it had cut springs and still had the squish they were just shorter. The lowering springs seem to be tighter, less flex therefor less squat. jmo:)
 
Ira R. said:
That is a great picture Brian.

Ira
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I agree. If i had a picture of mine doing that I would frame it and hang it on the wall. Not being a die hard racer I would think that the rear dropping like that would be perfect as it looks to be planting the rubber right into the track rather than spinning and loosing traction. Just my thought

Ken
 
kenewagner said:
I agree. If i had a picture of mine doing that I would frame it and hang it on the wall. Not being a die hard racer I would think that the rear dropping like that would be perfect as it looks to be planting the rubber right into the track rather than spinning and loosing traction. Just my thought

Ken
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You mean like these? Speak with Sally, the godlike woman with the camera :)


DSC_0186-1.jpg



DSC_0110.jpg
 
THere does appear to be a difference in the two pix of the cars. One of Brian's car showing the suspension at (what appears to be) full travel, and Ira's is close but I think there is a bit left. Only way to measure that would be to raise the front end and see what the difference is in the drop.

So to answer your question for the suspension; Once the front end is that high, a majority of the weight is now put on the rear suspension. Without going to a stiffer spring (pretty sure you do not want that on the rear of an IRS car) or to put air bags in. The suspension can only handle so much weight and that is actually increased over the weight (its actually force) as the vehicle takes off since the rear end is trying to climb under the car towards the front.

So...go on a diet or add some air bags would be my suggestion. However, what is the problem with what is happening? Are you getting too much bite right of the line and causing a bog or are you just concerned about the way it looks?

SWS
 
you turbo guys are starting to sound like honda owners.

real men race from a dig. if you have to go from a roll. you can't drive for crap.
 
seawalkersee said:
what is the problem with what is happening? Are you getting too much bite right of the line and causing a bog or are you just concerned about the way it looks?

SWS
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I guess my real concern is that my 60' times in this car are at VERY best high 1.6s. Car launches hard off a trans break and two step, sticks pretty well, weighs less than 3400#s. Maybe I'm expecting too much but I don't think so and I trying to figure out what's keeping the 60' times higher than I would like.

Seems like I'm burning energy rotating the car in lieu of pushing it here.
 
SCrazy said:
I guess my real concern is that my 60' times in this car are at VERY best high 1.6s. Car launches hard off a trans break and two step, sticks pretty well, weighs less than 3400#s. Maybe I'm expecting too much but I don't think so and I trying to figure out what's keeping the 60' times higher than I would like.

Seems like I'm burning energy rotating the car in lieu of pushing it here.
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It seems surprising to me as well. I am in the 1.6 range for 60 foot but the diffrence is my car weighs 3800 lbs without me in it. Sounds like you should be a little quicker not only in the 60 foot than me but overall ET as well. Less than a tenth of a second between us. Maybe your concern is justified

Ken
 
More stall, more gear, higher shift point? Tires screwed down? Mark the tire and see if its turning on the rim. I just screwed down the inside of mine and it seems to be working fine that way.

Do you have a data log we can look at? Sorry if I missed it in another thread. Your torque is kinda low in your sig. I have 440 torque at 4k and pull low 1.6's high 1.5's at about 3900lb race weight. Mine doesn't squat as much as yours in the pics I've seen. Stock shocks on firm and eibach springs.
 
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Chris:

Both data logs I posted in the "Tuning at the Track" thread were both high 1.6 60' launches.

Converter stalls at about 3800 and I've been launching at 3400 which has yielded the best results, gears are 3.73. Last year running around 12s I was trapping at a little over 6k rpm now at 11.6 I'm down around 5700....I might have room there for a gear change...not sure.

See now....it's 60' #s like this I hear from you and Ken that make me think I'm missing something.

I've not checked to see if the tires are slipping on the rim but I'll do that.
 
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I pulled consistent high 1.6's at the shootout last year. With the trans brake and 2 step I'd expect you in the 1.5's with that converter for sure.
 
If you are running lowering springs your car is probally bottoming out the rear suspension.
The front end lift can be limited. This gives a better reaction time, its also slows your 60'.
My guess get rid of the lowering springs.
 
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