wolve

hello guys,

as some of you might've seen my setup in the allmotor or forced induction threads i wanted some advice from you guys for slicksizing.

the case is:

a few weeks ago i went to SantaPodRaceway (GB)
being that i live in holland that is 400miles away from where i live
once arrived at the track i switched front wheels, lowered the rear and of we go

that weekend i had some 195/55/15 (23.5inch) yoko advan a048 strapped on the front. not the ideal drag tire but hee, i'm a collegestudent and it was a streettire-event.

i ran a 13.3@103mph allmotor and a 12.3@119mph on spray.
problem is, i was riding the revlimiter for the last 20-40 yards@8700rpm on a near empty bottle (2lbs left) and at ~90% of the nitrous i ran on the dyno(~320whp)

the problem is i'm in the market for slicks for next event in holland, i can get some 13x7.5j lenso's for cheap, and i'm stuck between a 23 or 24.5inch slick.
next event i'll be running somewhere 320-340whp and i'm scared to again reach the limiter in 4th if i run the obvious choice for my powerlevel, 23's.

now my main question is, how much mph do slicks usually rob in comparison with streettires?

because i was running a 23.5inch radial at ~300whp and riding the limiter in 4th(@120mph), so i know a slick takes away mph, but does it take away so many that i can run a 23inch slick and stay of the limiter?

and no, i can't raise the limiter as my setup is the folowing:

bone stock jdm '96spec b18CR (stock VT, everything)
stock exhaustmani (will be an vteckidd RMF copy before next event)
WAI with apexi filter
2.5" kteller/magnaflow exhaust
680cc precisions
progressive dry nitrous (single nozzle)
ectune


and don't mind the dip in the graph on spray, had no time to straighten it out on the dyno, did it on the track


will 23's eat enough mph to keep me under 118mph on full power?
will 24.5's be to big and slow me down?

this will be first time for me ever on slicks, remember i'm a poor student

92redhatch

GO 24.5 . you dont want to be on the limiter with nitrous.

93lxh22

deff 24.5

wolve

thnx for the concerns of my revlimiter

but my revlimiter is ignition cut only and my nitrous stops spraying 100rpm before cut and does not update during cut

so it's not dangerous for my engine, just annoying...

anyone have experienced mph drop when switching to slicks and how much?

wolve

what size are you running on the H2B? what power/weight?

gtistile

it wont be drastic. if you're having to pedal at all on the street tires you may even gain mph. personally I would go with th 24.5

92redhatch

At the 8th mile i went 9.0 at 88mph on 24in tall street tires. i switched to 22in mt slicks and went 8.0 at 89mph. bouncing off the limiter in 3rd. so im sure i would have went 90+ with a taller tire.

wolve

dajum, a full sec faster on the 8th...
but you also switched to a smaller tire/"shorter gearing"

i'd be happy if i could scrape of 0.5 sec on the quarter.

old setup with 50 shot+unprepped track was also a 8.9sec@88mph 1/8mile.
now 8.2sec@93.4mph 1/8mile

anymore experiences from swapping on slicks and mph results?

champLSinteg

At 8700rpm with a gsr tranny and your 23.5in tires you should be in the high around 130mph! I dont see how you are trapping ~120mph unless you have a b16 tranny. If thats the case then go with a 24.5in slick.

wolve

i have the s80 tranny that came with my jdm '96spec ITR block

so it's the ITR gearing with the 4.4FD, the same as the b16a2

it going towards 24.5inch more and more

wolve

http://www.youtube.com/watch?v=JEXUdk3wffI

1st day at the weekend, spraying from 2nd gear and detonating like hell
i'm running the right lane at 1:18min

racing the E46 Vortechcharged M3, poor sucker never stood a change

93lxh22

i run 24.5 with 240whp 2400lb i tried 23's but i was on the limiter going though the traps. I have a b16 trans with itr lsd and 4.7 final drive

Ls_dx

iTrader: (5)

24.5's

rick_rabies

dangg

fatboy1185

what rpm was the limiter at.

93lxh22

8500rpm

base-op.1320

A friend of mine has a turbo gsr with gsr trans making 336whp went 11.8 with 23" slicks and went 12.5 with 24.5" tires. Didn't bounce of the revlimiter either run.

eg6-itb

MORE INFO!!

wolve

what where his trapspeed and rpm trough the lights with the 23 and the 24.5?

i'm not concerned that i don't have enough grip, gearing is a issue

bruised eg

Don't forget to take tire growth into account. On a 225-50-15 bfg d/r I have to go into 5th at about 1200' and cross at 119 to 120 mph, with 24.5's I cross the stripe at 124 mph in 4th. I don't know if the growth will get you to the end, but if you go with a 23" slick on a 13" wheel it will def. grow some.

wolve

i'll be running 13/7.5j lenso's
i'll have to wait for exospeedAMcrx to reply my PM and see what he says, but it looks like i'm going to a 23 inch after all.

the FWD classes that are within my reach are:
- 12sec index sportsmanclass
- 10.9 sec index superstreet class

if i want to be competitive i'll have to choose the sportsman class.
so during free practice i'll be trying to run as fast as possible.
but during qualifying and eliminations i'll have to run as close to 12.0 as possible

to achieve that i'll probably tone down the nitrous up top resulting in lower trapspeeds and concentrate on my getting my 1/8mile et's down.
so i can run competivly and concentrate at putting some nice launches and 1/8miles down at the same time

worst case scenario i'll have to practice my 4-5 shift (affraid of the ever so unfortunate 4-3 misshift)

base-op.1320

I was saying he didn't bounce off rev limiter at the end of the track I am not sure what his actual rpm was, I believe his mph was 119 for the 11.8 and 116-117 for the 12.5

220 ek9

24.5 FTW!!!!

wolve

that would be about 7900rpm for the 23" (kinda ideal)

and around 7100-7300rpm for the 24.5" (to low in the powerband)

kinda logical

if the 23's carry me just over the line they'd perfect

btw 11.8@119mph is kinda my goal for this season