Knocking the tires off, Need Help.
10-02-2016, 06:19 PM
#1
Racer
Thread Starter
Knocking the tires off, Need Help.
Guys, I am looking for some insight.
Car is a FI (800 rwhp range) with a A4 & 3500 stall, 3.42 gear, I just removed a 3.15 gear. Same problen with the 3.15's. Tires are 295/45/17 MT, and @ the track, I run around 17psi. Front shocks are Vikings set @ 2RB & 12CP, NO front sway bar. Rear shocks are stock with large sway bar. (Car does squat pretty bad on launch).
Will not 60' at all, blow the tires at will.
Any thoughts and suggestions is appreciated.
Car is a FI (800 rwhp range) with a A4 & 3500 stall, 3.42 gear, I just removed a 3.15 gear. Same problen with the 3.15's. Tires are 295/45/17 MT, and @ the track, I run around 17psi. Front shocks are Vikings set @ 2RB & 12CP, NO front sway bar. Rear shocks are stock with large sway bar. (Car does squat pretty bad on launch).
Will not 60' at all, blow the tires at will.
Any thoughts and suggestions is appreciated.
10-04-2016, 07:32 AM
#3
Racer
Thread Starter
Launch
At first, I was leaving off of the brake around 2200 rpm, and it would flash around 3500 into boost and blow the tires. I found leaving around 1000 rpm would actually let the car bite for a second, but would still blow the tires at the 60' when the boost would ramp in.
I did notice Sunday morning that the tires are getting into the top of the fender wells. Maybe it is squatting so much the camber is not letting the tires plant.
Yesterday I ordered a set of double adj shocks for the rear to stabilize the rear. Also considering removing some timing until the car is planted.
I did notice Sunday morning that the tires are getting into the top of the fender wells. Maybe it is squatting so much the camber is not letting the tires plant.
Yesterday I ordered a set of double adj shocks for the rear to stabilize the rear. Also considering removing some timing until the car is planted.
10-04-2016, 09:39 AM
#4
Melting Slicks
Have you gotten any videos from outside the car to see what it is doing on the launch? If the front is rising but the rear suspension is being compressed as the weight transfers that could be a problem. Instead of pushing the tire into the ground immediately, the rear is compressing until it bottoms out. At that point the force is too abrupt and the tires break loose.
You could play with timing and also try setting the rear shocks stiffer. I have the LG coilovers and they are full stiff in the rear. If the car still won't 60 foot, you may have to go with a different tire. You could just be overpowering it at this point.
Are you at wide open throttle when the tires break loose? You could try squeezing the throttle so that you don't hit wide open throttle until after the power is ramping in. Three things could all be happening at the same time. Torque converter is fully engaged at 3500, boost is building, and car is at wide open throttle. You would need to lessen one of the variables. Not being at wide open throttle so quickly may help.
You could play with timing and also try setting the rear shocks stiffer. I have the LG coilovers and they are full stiff in the rear. If the car still won't 60 foot, you may have to go with a different tire. You could just be overpowering it at this point.
Are you at wide open throttle when the tires break loose? You could try squeezing the throttle so that you don't hit wide open throttle until after the power is ramping in. Three things could all be happening at the same time. Torque converter is fully engaged at 3500, boost is building, and car is at wide open throttle. You would need to lessen one of the variables. Not being at wide open throttle so quickly may help.
10-04-2016, 10:51 AM
#5
Racer
Thread Starter
Thanks
Thanks again for the suggestions.
I do not have videos of the passes, but know for sure the tire is getting into the top of the wheel liner. I have a set of double Adjustable shocks coming later this week, I will get them on and stiffen up the rear end. As suggested, after that if I still have issues, I will look at pulling some timing off of the hit. I was considering a M&H 325/45/17 to replace the M/T 295/45/17.
I do not have videos of the passes, but know for sure the tire is getting into the top of the wheel liner. I have a set of double Adjustable shocks coming later this week, I will get them on and stiffen up the rear end. As suggested, after that if I still have issues, I will look at pulling some timing off of the hit. I was considering a M&H 325/45/17 to replace the M/T 295/45/17.
Last edited by 1slowride; 10-04-2016 at 02:19 PM.
10-10-2016, 10:37 AM
#6
Racer
Thread Starter
My new Viking double adjustable shocks will be arriving today, and I plan to install them tonight. Viking suggested I set the compression & rebound both on #12. Setting are (soft 0 to stiff 18).
10-11-2016, 07:00 PM
#8
Tech Contributor
Have you tried more pressure than 17psi? If not, I would recommend starting at 23psi and lowering the pressure each pass until you get the best results. 17psi is usually what I find to be the absolute lowest pressure before they become useless again. What happens is the sidewalls push down and the center collapses at a certain point in pressure. It takes time to get everything dialed in. Just be logical and methodical about it and you'll get there.
10-11-2016, 08:48 PM
#9
Racer
Thread Starter
Tire Pressure
Just finished installing the Vikings, and have them set at #12 compression & rebound. Maybe the tires will plant now.
Demonicbird, I have to say lees power is not a option at this point, lol.
Thanks BlownblueZ06, I will start out at 23psi as you suggested, and drop from there. A question, hot or cold 23 psi? I will say I went to 17PSI cold last weekend, and it seemed to move around on me at the top of the 1/8th. Car will normally trap 117-118 mph.
Demonicbird, I have to say lees power is not a option at this point, lol.
Thanks BlownblueZ06, I will start out at 23psi as you suggested, and drop from there. A question, hot or cold 23 psi? I will say I went to 17PSI cold last weekend, and it seemed to move around on me at the top of the 1/8th. Car will normally trap 117-118 mph.
10-11-2016, 09:23 PM
#11
are you turbo or SC?
SC is def out with the method i said, but being turboed, you can progressively increase lbs per rpm http://www.enginebasics.com/EFI%20Tu...By%20Gear.html
just throwing out an option that maybe you may have missed.... less power is never an option
i agree! but launching off say 5lbs is better than launching off 17.
like i said, im still new at FI, so please dont take my .02 as an insult
-brandon
SC is def out with the method i said, but being turboed, you can progressively increase lbs per rpm http://www.enginebasics.com/EFI%20Tu...By%20Gear.html
just throwing out an option that maybe you may have missed.... less power is never an option
i agree! but launching off say 5lbs is better than launching off 17.like i said, im still new at FI, so please dont take my .02 as an insult
-brandon
10-12-2016, 08:01 AM
#12
Racer
Thread Starter
S/c
Car is Supercharged. The converter flashes up kinda high, thus leaving on good power. I will play with the suspension a little now, and see where I am with it.
10-20-2016, 09:44 PM
#13
Say suspension doesn't work.... as I'm sure you can eventually get it right, I'm going to throw a more complicated setup out lol. You could always do the big wastegate setup and use a boost by gear controller like the Boost Leash. Way more complicated lol, but hey more ideas out there you know haha.
10-21-2016, 05:32 PM
#15
Racer
Thread Starter
Timing
Should get a chance to get to the track this weekend and tune the shocks. Next step will be as suggested by realcanuk, we will pull some timing to get the car to plant.
Thanks guys.
Thanks guys.