tylerxfire

iTrader: (15)

hey guys, well it is almost that time of the year...I havent ran since last year but have been thinking more about it for the up and coming season...I ran 11.90@115-116 mph last year..I pull consistent 115-116 mph and with my setup i have to hit 5th gear right before the line which sucks and i know is taking a little time off!!! i run a 17" MT ET street which i beleive is 26" tall tire..With my setup now i dont get swaying but have heard with a 27" tire most people do get the swaying feeling if they dont run skinnies in the front which i am not going to do...I am pretty sure that switching to a 27" tire would solve hitting 5th gear but i do not want the swaying and really dont want to have to buy new wheels and tires as i dont go to the track very much and already have what i am using which works very well besides having to shift to 5th..Does anyone have useful info on other options to get around shifting to 5th or am i stuck with this if i dont want to change the tires or bump the rev limiter?..I have really been against bumping the rev limiter on a F/I DE so i am leaning against that mostly.

Would tire pressure play a part in this? say if i aired my tires right up to the max would i still need to hit 5th assuming i could still hook? I have only tried them between 16-20psi

which would u do? or any other suggestions
1. change to a 27" tire
2. bump rev limit a little higher
3. leave it on the rev limiter crossing the line in 4th
4. keep shifting to 5th until i decide i really want to buy different wheel and tire setup


thanks for the time

tylerxfire

iTrader: (15)

curious on if tire pressure would make the difference now that i am thinking about it...anyone?

davidv

iTrader: (2)

The extra shift hurts ET. Crossing the finish line at the bottom of 5th instead of the top is 4th gear is bad. Besides changing the final drive, you may be able to get away with new tires. See if the tire calculator here is helpful: http://www.wallaceracing.com/Calculators.htm

tylerxfire

iTrader: (15)

thanks for the link, from everything ive read changing to a 27" tire would do the trick..alberto was just recently telling someone else this..I just really dont want to buy another set at this time and i plan to only go to the track once or twice this year so it wouldnt really be worth it to change tires at this time imo..

do you know or think that a higher tire pressure would make any difference or is that a waste of time? just seems that if it were a higher psi it would make the tire slightly taller than being aired down and maybe i could hold 4th gear out slightly longer that way? just a thought

if not then i will most likely just deal with shifting to 5th as its not like i go all the time but i would like a little better time and i know it would make the difference to get to 11.8x's

i also want to try holding it at the rev limiter in 4th crossing the line instead of shifting to 5th to see what the outcome is..

str8dum1

iTrader: (11)

tire pressure wont matter. leave it where you hook the best on launch. I'd just bump the rev limiter for track days. thats free and you said you dont go much. kinda silly to drop another 500$ on tires you barely use. bouncing off the limiter will KILL your ET.

oldman350z revs his out to at least 7200.

new tires would be alot more expensive than even a final drive swap.

Nealoc187

get a 27" drag radial, that's what I'd do. solves all your problems. no swaying, no more shift to 5th, no increased rev limiter on stock rod bolts (something I'm wary of as well).

if you have a dyno plot of your car I can run it in cartest2000 and see what happens with some different options. I've done this for both my car and briguymax's car extensively and the results are always dead nuts with what happens at the track after we make such-and-such change to our setup (tires, power, rev limiter, etc. whatever we change I test it out first).

tylerxfire

iTrader: (15)

thanks for the reply..i did not know oldman was revving it out like that..damn if i were to rev it out i know it would help alot i just have heard bad things about bumping it up..i really only need another couple hundred rpms's though to get thru so seems like the most logical thing to do...too bad its not free for me to bump the limiter up though..ss box lol..

maybe i will do the t.s. reflash to bump it up and just use that for the track to get thru the trap in 4th and still shift at 6600 in all other gears and at all other times

tylerxfire

iTrader: (15)

ive thought about the 27" tall drag radial but am wary of that as it is more of a shock to the drivetrain than a bias ply tire...any tire recommendations to look at? anything that will fit a 17" wheel?

tylerxfire

iTrader: (15)

^^ ive been lookin for a dyno sheet for the last hour and cant track even 1 down..frustrated, my girl prolly threw them out cleaning and didnt realize..

i emailed vinny ten to see if he has any on file to send me

ajcool2

iTrader: (11)

I raised my rev limiter just to see how holding my gear through the traps would change my times and there wasnt any major difference. I'm really not comfortable doing it truthfully so Ive been shifting at stock rev limiter. Of course it may be different since your a boosted 6 speed. I'd say try it and see what happens.

tylerxfire

iTrader: (15)

^^according to the graphs ive seen on gearing, the stock gearing is good till 114 so me crossing at 116 in 5th is just into 5th and not good, i think the auto gearing is different