what is a safe shift point for our cars, so as not to screw anything up (bend a pushrod, etc.). i've heard a lot of different opinions on this, just thought i'd take a quick poll. my mods and everything are in the sig. also, i have nitto 555r's (not the drag radials), what is the recommended psi for these at the track and on the street?

 

I shift mine at 5600 in first, and aroud 5700 in the other gears. I shift sooner in 1st because the tach cant quite keep up with the motor while increasing revs.

 

not sure how accurate that statement is.. My car was on the syno and was being shifted at 6K

The readout on the computer shows the RPMs as well. The driver was using the tach built into the car..

he ran it to 6k and it would correspond properly..

I run mine to 5900 since i stop making power at about 5700-5800 then I shift so that I can keep the rpms higher..

 

I have a calculation you can do to figure out your exact RPM shift points for the fastest possible 1/4 ET but I would have to find it. It takes into account many variables.

 

alright thanks guys. what about the psi on the tires?

 

Well your Nitto's may be different. I was running 30 PSI in my Yokohama AVS-I's and a guy told me to take them down to 22 PSI. I was a little nervous about going 100+ MPH with less than 25 PSI in the tires. So I only took them down to 25 PSI. It took .2 seconds off my 60' time. That was my last run so I didn't go to 22. I'll try that next time. I beleive Nitto usually has some pretty specific instructions on how to get their tires to hook up the best. It's either on their website or on Tirerack's website. I was surprised that such a low pressure would help this much. Keep in mind, Eagle F1's supposedly get less traction if you drop them down that far. I was told that it's because of the 'run flat' design of the tire. It all depends on the design of your tire.

 

Agreed with what he said.

honestly I think the best way to go, is keep them presusred up high, and drop them slower and slower to see if traction improves, I have gone on many times to try different things, on different sets of tires in a short amount of time.

with my current setup I actually run better at around 35-38 psi(wierd), then at 25 psi, like I did in an older set of tires. I also noticed the stiff sidewall thing(who would have thought chuck), I lit the tires up to test it out and sure enough, I can see I am have darker patches on the outside of the tire, but lighter in the middle insinuating that the middle wasn't getting enough traction, do that with lower tire pressure, the middle caves in instead of the sidewall. It takes ahwile but its always nice to find that sweet spot between spin and bog, with the launching rpms, and the tires.


yikes jsut noticed I am in the ls1 section.

 

Yeah! That's right! You and your big V6 had better get out of here! You big wannabe.