Blackbird CPV35

iTrader: (19)

Im in the market for some new bia ply et streets and the wheel I am using is a 1993 RX-7 wheel. The only options I have are a 26x10.5-16 which actually has a smaller diameter than stock or a 28X11.50-16 which has a diameter a little over an inch taller.

I would like to go with the taller tire because at 550 RWHP the gears go by too damn fast. I am still on the 3.5 FD as well

Anyone have experience using a 28 in tall tire and what are any potential drawbacks besides the obvious loss of power

thom000001

You get a lot of gearing help. You are right on the edge at 550rwhp but they will help you. Won't have to shift into 5th or even worry about being at the rev limiter in 4th.

I know SP is running a 28in tall slick (1.4 60') but they rev to almost 9K rpm too.

I think the sidewall height of the 28in tall tire also helps put less shock on the drivetrain (but that is a guess)

tom

Blackbird CPV35

iTrader: (19)

550 was actually last year, im probably going to crank it up to around ur hp level

thom000001

The gearing change will definately help,
how high do you rev?

tom

Alberto

iTrader: (14)

If your running a bias ply front do the 28" rear. If your still running radials up front dont even try the 28" the float will be horrible. Why not run a 27" tire as a compromise? I tried that setup last season but it wouldnt work for my situation.

I run a 26" tire but can rev to over 8000rpm's, also with a 3.3FD = 140mph+ in 4th

Blackbird CPV35

iTrader: (19)

I rev to 7200, but im pretty sure i can go higher because i have a built head. the car just doesnt make any power up there though.

I would run the 27" but they discontinued the 27x10.5-16 and I have to run a 16 because of my brembos

i could run a bia ply up front but they only make one size that would fit and its a 17 x 2.5 or something and being on a tire that skinny kind of scares me

thom000001

7200rpm, 3.5FD, 28in tire 4th gear is 134.8mph......thats plenty of mph to put you in the 10's.

tom

thom000001

yea, think we'll do cams on mine later in the season....no point reving too much higher than stock redline with stock cams...power and tq are dying above 6200rpm......i'll be bumping it up a touch though just to run through the traps in 4th (and not be on the rev limiter) before we change the cams.....FYI I did the 3.3FD swap this weekend, helps a little so far but roads are too cold to hold much of any power yet.

tom

Alberto

iTrader: (14)

Use 2 factory donuts on skinnys that's what I will be doing. If you run a tall sidewall (bias play) rear and street radial front you will do this

http://www.youtube.com/watch?v=qe8bBfMi6uw

Blackbird CPV35

iTrader: (19)

I think my donuts are 18s. are you going to use the bias ply et fronts?

scotts300

iTrader: (46)

HA!! That walk looks like what I experience at the top-end with the MT ET Streets and street radial up front. It's pretty hair-raising at 130mph.

txshldm

iTrader: (4)

what makes it do this? and what kind of front tire do you need to stop it?

scotts300

iTrader: (46)

It's having a bias ply tire at one end and a non-bias ply tire at the other. One can run the MT ET Street Radial, like the OP is going to do, with radial front tires, deal with the walk, or run a non-radial rear (MT ET Street) with a non-radial "skinny" front.

txshldm

iTrader: (4)

How do you think my et street radial and street tire in the front will do?

OldManZ350

iTrader: (23)

28's (275/60/15) M/T et street Radials rear
26/6/15 M/T Sportsman S/R Radial front

I rev to 7000, had 26's and was still hitting the rev limiter in 4th
So, went to the 28's

Pro's: Hooks much better, and cut .30 off my 1/8 mile, and .16 off 1/4 mile
con's: did not pull as hard in 4th gear, lost 1 mph on 1/4

This is with about 430-450whp max

Blackbird CPV35

iTrader: (19)

I think u mean run a ET Street Bias Ply in the rear and deal with the walk, which i was doing all last year. Its kind of like driving an old floaty Buick at 125 mph

Blackbird CPV35

iTrader: (19)

woot, thanks for that input. It will probably be better for me with a 28 then.

What was your 60' with the 28s

OldManZ350

iTrader: (23)

1.76 60 ft, but only have 13 runs on the car total, only 2 runs with the 28's
I come out of the hole @ 4200rpm, not 7000 like Alberto
11.85@116.75 on 28's
12.01@118.00 on 26's and on rev limiter

Alberto

iTrader: (14)

I actually think FI Z's like taller gearing/taller tire. Oldman's times prove that. Going to a 3.3FD feels slower because your not shifting as often, but it keeps the car in the powerband longer. I counteract the 3.3FD with my 26" tire some, but my rev limit more than makes up for it

When running a bias ply rear/radial front, the front will act like ski's on your car. The steering will become hypersensitive, because as you make steering corrections or adjustments, the front will react quick (radial), and the rear will always be 2 steps behind catching up (bias ply) you end up with a butthole puckering ride. Notice my 1-2 shift sends me waayyyyy sideways and you can see I have to let off to let the car settle down. Scary and fun at the same time. I ran my 11.1 drifting to the left lane at the top end, I crossed a ****s hair from the middle line.

I will be running IIRC 17" Track spares with bias play next time I go.

thom000001

Oldman are you SC or turbo? For some reason I remember you being Vortec (not you really throwing a wrench into the guys going to 4.0x gears lol)

definately showing the positives of 28in tires at the strip.

tom