Can someone recommend a good drag radial that still performs decent on the street? The video is from my first trip to the strip, and although I have my times down to 12.6, I am still spinning all through first. Any advice would be appreciated. Go to the link and check out "porsche928".

http://www.properformancedyno.com/videos/

Thanks in advance.

Woody

 

Do you have room under the wheelwells for some big ole' M/Ts if you dropped down to a 15" rim and ran some 12.5" wide cheater slicks?(this would be a track only mod obviously)

I ran those on my 400+HP Buick T-Type turbo and they cut a full 1/2 second off my 1/4 mile times.

PS- nice vid.

As far as drag radials, i hear the BF Gs are pretty good, but i've never used them- street or otherwise.

 

Sniper,
I drive the car a few times a week and need something that works for both road and track without changing wheels. I am leaning to BFG drag radial 275/40 17. I currently have a little over 460 at the wheels(soon to be more) and street tires just aren't enough. Thanks for the mod info.
v/r
Woody

 

Nice video Woody.

 

Nice work!! Too bad you and Tony live so far apart....it would be fun to watch you guys run together!

I have heard good things about BFG drag radials....they wear out pretty quick...but should drop your times by about .5 or so? I don't know if they work well on a racetrack with turns though?
Brian

 

Woody, forgot to ask....what Psi were you running in the rear tires for your runs?

You should be NO HIGHER than 22psi in the rears. Believe it or not just dropping from the 36psi stock to 20-22 psi will cut several tenths off your 1/4 mile time(you can go even lower, i used to run my cheater slicks at 16psi, and the .5 ET reduction i quoted above was above and beyond the ET improvement i saw with street tires at 20psi vs the T-types stock 32psi rating, which was .2 sec IIRC). Also, pumping the fronts up to 50+psi will reduce rolling resistance, and will normally also cut another .1 or so.

The Porsche factory 1/4 mile and 0-60 times were accomplished using stock pressure ratings, so even in a bone stock car there is .2-.4 seconds available just by playing with your air pressure!(increased front, decreased rear)

I really have no idea how good drag radials are for twisties. The few guys i know that run them have mustangs, and most of those guys have welded rears, lol.

 

Sniper,
I tried 20psi last weekend and had slower times than with 36psi, go figure. I will try it again next friday and see if I was just having a bad day. I will also try raising the air pressure in the fronts.

It may be a while before I get back to a track event or autocross, so I expect to wear out and replace the drag tires before then.

Thanks again, Woody

 

" I tried 20psi last weekend and had slower times than with 36psi, go figure. "

Wow...that's highly unusual, lol.

The reason the lower air pressure works(well, on most cars anyway) is because it allows the sidewalls to flex or 'twist' on launch, thus softening the initial shock to the tires.

You have 17"s though, so it's possible that there's just not enough sidewall to flex at all, particularly if they're stiffer than the average sidewall. I really don't know what the 17" and up rim guys do, never asked any of them(never had a car with rims bigger than 16" or a sidewall lower than 245/45/16).

There is some chemical goo that a lot of guys i know who run mustangs use. You gob it on the tread before your burnout, and it makes the tires super sticky. I can't remember the name of the stuff, it's something like "liquid traction" or some such thing.

BTW, what gear/RPM were you at when you hit the traps?

 

Woody,

I've got my eye on this, too, as I am running the same HP (you at 10psi also?). I have Yokohama AVS100's and they break free in second gear as the rpm's climb (depending upon the road temp, etc.). What year is your S4? I've got an 89 with the 2.64 gearing & LSD.

Something with just a bit more grip might let me get through second and land in third at the right rpm.

 

Woody, nice runs! You might consider heating your tires a bit more, maybe get some bleach on them. Yeah, it's messy, but makes for some real soft, sticky rubber! Also, this will vary by tire, but I've found that the optimum tire pressure seems to be about 28 psi for 255/40/17s. My criteria for "optimal" is even pressure across the contact patch, tested using chalk across the tread, pyrometer readings and by observing tire wear closely. Also by checking the triangle marks on the side of the tread to ensure the tire is not rolling over excessively. Yoko AVS ES-100... YMMV.

 

Woody,

I run 295/30/18 bridgestone SO2a's on the rear on 18x11 Fikse wheels. I use 32 psi and still get wheelspin through 2nd gear with an aggressive launch. I get enough traction for a sub-4 second 0-60 on the g-tech withoutabusing the car on launch ( still have not run a full 1/4 yet with the g-tech--soon). If you have the stock single disc clutch, be carefull with the drag radials. If something is going to "slip" on my car, I would rather it be the tires.

Tough to have these problems, isn't it?

Jim

 

Hi Jim,

Sounds like we have the same setup - '89, that is.

I went to the dual plate clutch...

Woody, what year?

 

Get a good set of drag radials. BF Goodrich makes an excellent drag radial.

 

Hi Woody,

what all did you do to your car?

LO

 

Woody,

Go with the BFG Drag Radials. They are very good, and I know from experience. They do wear out alot faster than normal tires, but I was daily driving them around for about a month. Don't kid yourself with street tires... r-compounds and stree-compounds are completely different.

If you're interested in sticky street tires, the BFG KDs are about the best i've found. Right before I lost my car, I had SO-3s in front and KDs in the back. I swapped them around and the SO-3s were much worse in straight-line traction.