What tire pressures do you run at the Drag Strip ??

[JH23JOB]

What tire pressures do you run at the Drag Strip ?? I'm running stock 17" Michelin Pilots on my '96 GTS, and I'm wondering what the optimum pressure would be for the rears and the fronts. I'm guessing about 23-25 lbs rear, and 30-35 lbs front. Am I way off base with my guess ??

 

[Chuck 98 RT/10]

18 - 22 rear
45 - 50 front

Don't drive to the track like that. It's pretty squirelly.

 

[Eddie N]

but (insert name here) from (insert magazine publication here) recomends running normal tire pressure on street tires.. he also says that running lower pressure does nothing to lower ET's..

hopefully 1badgts will chime in with his take.. i believe its more about allowing the tire to give more than increasing the contact patch, but i am surely not a professional..

- eddie -

 

[HP]

Time and time again, there are posts by members that get
better times, with lowers pressure on rears(20-25lb) there
seems to be little to lose by running the fronts to 45-50lb.
The physics that allows slicks to run with low pressure would
probably also pertain to streets, and normal rules of stationary
contact patch would not apply - the dynamics of a spinning tire
changes that. Of course there is a point where the rear tires
may spin on the rims, and that should be avoided at all costs.

 

[Mike Brunton]

I'm not much of a drag racer

, but MY take is...

Street tires have very stiff sidewalls compared to slicks, so if you lower the pressure too much, the sidewall gives a bit and actually will cause the tread of the tire to sort of cup upwards in the middle. Tom Welch has a good method of getting the exactly right pressure - doing burnouts and looking at the tread pattern until it's even all across.

As for pumping up the fronts... ehh, I don't think it does anything. The lower drag isn't going to be noticed. It reminds me of when I was at a VOI and they were giving tips out on drag racing. Guys were folding their mirrors back for decreased wind resistance, adjusting their tire pressures in 1/4lb increments, pumping up the fronts, removing the spare tire, removing junk from the glovebox, resetting the ECU for a 'richer' mixture, and all sorts of stuff like that. Then these same guys tend to run a 12.95@109 in their GTS. Did the stuff they did help? I dunno... but I'd concentrate on the basics first.

Ultimately, it comes down to how much can you put down - and that is probably more a function of your technique than it is of what your tires are set to. My *personal* experience has been that lowering the pressure tends to hurt the times. I always seemed to run my worst 60' at 18psi, and my best ever was at 30psi. Go figure.

But like I said, don't take my word for it... I don't really know what I'm talking about.

 

[HP]

Mike, looking at the rules, if you run Norman in the ModII
class, and he runs under 10.50, then he would be disqualified,
and you would win. Just a thought..
P.S. I think I'll change my mind and have you send that shift-light, If you don't have my address, I'll resend it.

 

[Chuck 98 RT/10]

Evan Smith is a pro, correct? His style may work better with the stock 29 psi and I wouldn't argue with him to lower it. If I ever reach that level, maybe I'll be able to run 29 also.

Brunton is just a natural, God had to give him some talent since he was shortchanged so badly in the looks department.

I made sure I ran consistantly before messing with tires. The same goes for Rob. Neither of us are pros. But the results and gains were identical and consistant. For the time being, I'm sticking with what I've seen work for me.

 

[95Viper]

1bad gts, I plan on going to the track for the first time within the next few weeks. Not too sound like a stupid question but how do I keep the engine cool? Is there a place to shut off the engine between runs? How long should I wait? What temp should it be? I assume cars line up to run down the track, doesn't it only take a few seconds to get hot again? Thanks!

 

[Mike Brunton]

Oh my god, I agree with 1 Bad GTS!

I've been to the dyno a few times and it's absolutely correct that a cool motor is good for +20 to +30hp more than a heat soaked motor.

95 Viper, the best way to keep the motor cool is to...
1) After you run, pull over and open your hood, shut the motor
2) Don't be idling in the lanes longer than you have to.
3) Run your fan when the car is off to cool the motor (you would need to install a switch)
4) If you can stand it, when you are in the car and the engine is running, turn the heat to full and crank the blower - it will get hot in the car but that is heat that isnt in your motor

You could always buy a bag of ice for the intake, but in my experience most folks laugh at the guys icing their intakes

HP, I still have your address, I will send it out to ya!

 

[Chuck 98 RT/10]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by 1bad gts:
he usually does not even measure the air pressure in the tires.
<HR></BLOCKQUOTE>

If he doesn't measure the pressure then how does he know that it's not 20 psi???

Nevermind, just being a smartazz.

 

[Tom Welch]

Hello,

a few quick tips;

Set stock tires to 22 rear and 35 front.

Do not run cold..warm up the rear end and other fluids and make passes at about 180 water temp. Failure to warm up the rear end will damage the clutches that make your posi unit work(if you drive the car to the track you will be fine). Do not cool the engine by icing the intake with ice bags as water will puddle in the intake tray and upon acceleration can seep through the engine transmission mating surface and onto your flywheel and clutch.

WHEELSPIN IS YOUR ENEMY. There is a fine line between blowing the tires off and bogging the engine, and it takes practice to find the right amount of clutch slippage(will not hurt anything) to get the job done.

track conditions make a major difference..a poorly prepped track is worse than driving on a street.

DO NOT BURN OUT WITH STOCK RADIALS. All you are accomplishing is tearing up the track surface for the real race cars, as a matter of fact you are going to find small "dog tird" looking pieces of rubber on your tires after a water burnout which are rolled up pieces of rubber from the track surface. You will not get maximum traction with them stuck all over your tires.

DO NOT ALLOW ANYONE TO DRIVE YOU THROUGH THE WATER BOX, OR GET WATER ON YOUR TIRES....DO NOT DO A WATER BURNOUT. Water will get in your treads, fenderwells and when you stop at the starting line, gravity will create a puddle under your tires....

shift at about 5500 and SHIFT INTO 4TH GEAR.

Do not speed shift, it is possible to wheel hop from speedshifting the 1-2 and sometimes the 2-3 which can cause failure of your stock half shafts depending on track conditions.

There is alot more to going down the dragstrip than meets the eye. Try my dvd or vhs to help answer your questions.

Best of luck,

Tom Http://btrviper.com

 

[HogWhisperer]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Tom Welch:


a few quick tips;


<HR></BLOCKQUOTE>

Tom, Evan is not going to like you giving tips like that! Especially when they conflict with his....

 

[Eddie N]

i am actually nearly convinced that 1badgts is actually evan smith, and that he just likes referring to himself in the third person

...

is speed shifting the same as power shifting? (not letting off the gas during shifts)

- eddie -

 

[USAF BAD ASP]

my best times, both 60 foot, and et, are ALWAYS better with stock tire pressure. Lowering it always seems to hurt.

 

[Chuck 98 RT/10]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Eddie N:
i am actually nearly convinced that 1badgts is actually evan smith,

<HR></BLOCKQUOTE>

Ed, I think it's a religion. I saw a bumper sticker the other day - WWED?

 

[Mike Brunton]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Eddie N:
i am actually nearly convinced that 1badgts is actually evan smith, and that he just likes referring to himself in the third person

...

is speed shifting the same as power shifting? (not letting off the gas during shifts)

- eddie -

<HR></BLOCKQUOTE>

That is f-ing HILARIOUS!!!!


As for your question, I have always believed they are two different things... I have also noticed different parts of the country use different terms, and different aged drivers use different terms.

When *I* say "speed shift", I mean let off the gas about 10%-20% of the way - basically if you shift out of gear when you are at 5,500RPM, you keep on the gas most of the way so you stay between 5,000-5,500RPM, but you don't keep it all the way down, or you'll bump the limiter and torque the driveline and it will be hard to shift.

When I say powershift, I mean keep your foot to the floor from the time you are solidly in 1st until the time you cross the line at the end of the 1/4.

I have tried powershifting the Viper... it causes more than 1/2 the runs to be duds because it's to hard to get the gear correctly. The few times I did get it right, I lost time and it's dangerous to be dropping the clutch in a Viper going 100MPH and an engine zinging along at redline. The solid grab of the clutch and the sheer mass & inertia of the rotating parts of the engine is enough to make any Viper lose traction under those conditions at almost any gear shift.

 

[Tom Welch]

1bad,

I always expect and appreciate your comments, even if you rely on the merits of others to make your points.

As for Icing the intake, a cold air charge is no secret in racing and there are alternatives to ICE Bags, like cool blankets that can lay across the intake. I have seen them used on LPE cars.

I prefer to have ACTUAL conditions when I race, as do many of the regular folk(not superheros like you so profess)as it is difficult at best for a Viper owner to haul a cooler full of ice bags to the track in trunk.

Question..Why would someone want to run stock tire pressure knowing that the contact patch is smaller than with tires set at @ 23 psi, but want to ice down the engine for the last bit of power?? Im confused.

It is easy to run 11's on a prepped track in a stock viper. We have done it many times. The average drag strip on a Wed or Fri nite test session is not prepped and the surface is usually worse than the average street, so to profess about a magazine test bed at a sea level, closed session, prepped track with optimum conditions is not only considered bogus boasting(in my book) but it undermines the efforts of the average Viper owner who takes his car to the track on a typical tuning session. You make these guys feel like if they can't run 11.70's with their stock Viper then they ****. Give the regular drivers on regular tracks a break, please.

With that said, Ice down your intakes if you can without creating a hassle for yourself. Make sure that you do a few "dry hops" to sling the water out of the intake webbing before you get to the front of the staging lanes or when you launch water will spill all over the starting line and ruin the track surface for those folks behind you.

Don't be upset with a 12.20 in a stock viper at sea level, thats what the RECOGNIZED magazines have listed in their data base for a Gen II viper.

Again, best of luck to all, give drag racing a try, you will love it.

Tom
Http://btrviper.com

 

[Chuck 98 RT/10]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Tom Welch:
not superheros like you so profess
<HR></BLOCKQUOTE>

Ok 1bad, you're up.

Let the smackfest begin.

 

[99 R/T 10]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Tom Welch:
I always expect and appreciate your comments, even if you rely on the merits of others to make your points.
<HR></BLOCKQUOTE>
Wheeww, Tom that's harsh.

You know 1 bad is coming back on this one.

Mike

 

[Chuck 98 RT/10]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by 1bad gts:
Smith if anyone is interested got Houss stock Viper to run 11.9
<HR></BLOCKQUOTE>

Hey Brunton, don't you run high 11s in your Viper?

Hey Pemperton, don't you run high 11s in your Viper?

Who else?

You guys should start your own religion too.

 

[HogWhisperer]

Man, I learned a bunch from this thread! Next time I take my Super Comp car to Ennis, I'm gonna forget about the 6 lbs. of air pressure I normally run in my slicks and pump those babies up to 29 psi. CRAP! I'm liable to pick up a couple of tenths!

CANT WAIT!

 

[JH23JOB]

I see lots of people post the same questions in more than one area of this board. Maximum exposure for something that I felt was very important when it came time to actually race the car for the very first time. In fact, you guys really helped me out, and I would bet I wouldn't have gotten the times I did without your advice from experience. Thanks !!!

 

[Eddie N]

i am pretty sure that everytime evan smith goes to the track they lay down at least a weeks worth of VHT to the track surface.. that probably helps out a bit.. unfortunately us amatures dont have that privilege..

- eddie -

 

[Chuck 98 RT/10]

No way Eddie. Like Jesus walking on water, Evan Smith could run high 11s with bicycle tires on a track of Crisco.

Now repeat after me,
Hail Mary,
full of grace,
Evan is with me...

 

[HogWhisperer]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Chuck 98 RT/10:
No way Eddie. Like Jesus walking on water, Evan Smith could run high 11s with bicycle tires on a track of Crisco.

Now repeat after me,
Hail Mary,
full of grace,
Evan is with me...

<HR></BLOCKQUOTE>

with 40 lbs. of tire pressure!

 

[J DAWG]

OK OK already. We all now know Evan Smith is god when it comes to driving a Viper. He gets more passes done a strip in a week than I will get in a lifetime. Its no big secret that practice will improve your times.This is not life or death Maybe instead of icing the intakes some should use the ice to cool themselves. Take it easy. Go to the track. Line it up. And let it rip. Have fun. I learn something new everytime and try to improve on my own times and not what some other smith runs. See ya at the track. Good luck.

 

[viper spray]

Listen to Tom, I bought the video and am much faster now that I use the BTR tricks. That video is worth it's weight in gold.