SVT_Z06

Me against a 550 hp SRT 8 Super Bee.

GARY2004Z06

Be very careful if you go to a radial tire. Wheelhop will break parts. I usually start around 21 psi with a Hoosier 275/40R17 at your power level. Since these will have less grip and smaller sidewall, I would start at 18 psi and go from there.
Good Luck.

Trash

I haven't run at Qualcomm so I can't attest to the launch pad prep. I also haven't run DRs. Having said that I've gotten as low as 1.78 with a normal street tire (Cont DW Extreme @ 25 psi). I've got a bunch of 1.8x as well but to get sub 2 seconds took a lot of experimentation/practice. I use more rpm than most to prevent bog and ride the clutch out as quick as I can. It's difficult to describe.

Basically I know its a good 60' when the motor doesn't bog, the nose doesn't drop and the tires hook. It would be nice to just side step the clutch but I'd spin profusely or disassemble the drive train at the tree.

Best of luck.

DVUSz06

Trash, if you don't mind can you tell me what rpm you are launching at. I'm thinking of taking my 02Z cam&header car to a test&tune day next weekend, but I have never been on a drag strip in my 53 years. Kinda a bucket list thing. I don't want to break anything or look completely stupid, but haven't a clue where to start. I'm running a similar tire, mine are the conti DWS. And any other advice would be greatly appreciated. Thanks

Trash

Gladly.....but....take baby steps on your technique.

When fully staged I have the rpm up around 5000+. As the last yellow comes on I ride the clutch out as quickly as I can where it won't spin the tires but I don't pin the throttle to the floor yet. By keeping the rpm near 5000k at the start it typically prevents bog and thus I just modulate the clutch travel. I'm probably traveling a full car length + before the clutch is fully engaged. At that point I pin the throttle and hang on.

Now mind you this is my technique. The big down side is this can be potentially hard on the clutch if you are riding it out too long so there is a limit. Ideally you'd want a little less initial throttle and feed out the clutch as you feed in the the throttle. The problem is the clutch let out and throttle tip in rates are different so you must split the right and left foot movement rates (does that make sense?).

All of my early passes were well north of 2.1x in the 60' department. Some were 2.75...yes 2.75. Most of those involved glorious tire spinning in 1st and 2nd. My initial goal was to simple break the 2.0 sec 60' barrier. I got like a 1.99 and was stoked. Then I got like a 1.94 and said, hey, maybe I can crack the 1.9 barrier. A few passes later I was in a string of 1.8x passes. I think I was at a 1.82 or so and then I got a 1.787. I was in disbelief yet pumped at the same time.

Reac 60' 330' 1/8th 1/8 mph 1k ft 1/4 Trap
0.541 1.787 5.175 7.982 87.02 10.367 12.378 111.46

(sorry for the formatting)

Ironically it was one of my lower trap speed passes, but I was at Fontana and the DA typically blows. Next pass I had a 2.4x 60' as I got greedy in my 60' quest and spun pretty hard in spite of me pedaling like John Force.

Let me also say that I don't crack off 1.7x or 1.8x 60' times all day long on these tires. BUT it is possible to run a bunch of sub 2.0 with effort. BTW my car is an 02 C5Z that is stock down to the AC Delco air filter. Tire pressure was around 25-26 psi and warmed up with a good burnout. Your initial burn out with those tires should be robust (5-7 seconds in 2nd gear). Subsequent burn outs won't need as much.

Since you have a cam/header combo you may need to massage your technique a little but I think you will find middle track and top end performance improvements from your mods.

Lastly, I mentioned timing clutch release on the yellow light. For test and tune stuff you can ignore all the tree timing as you aren't bracket racing. You could sit staring at a green light for 30 seconds if you wanted and it wouldn't affect your 60' or any other time. The staging crew might have a fit though....I simply use the last yellow light as an aid.

Best of luck and let us know how it goes!

SVT_Z06

Thanks, brother. Gonna try to see if things improve with my almost new drag radials.

SVT_Z06

Here are a few of my runs. The Jeep SRT8 run slip is in the original post. He ran a 7.3.

Trash

Can't wrap my arms around 1/8th mile stuff. Its over too quickly....

Stroker87

street tires around 2k +/-rpms, put the car in competitive mod that way if it gets side ways traction will kick on drop your tire pressure to 23psi cold if the tires are hot 25psi

depending on what it does adjust from there, if you spin lower your launch rpm and ease into the throttle (dont stab it) if you hook and bog raise rpms and get into the throttle faster the car will tell you what it wants

7.3 1/8 mile is good for mid 11.4-11.5

DVUSz06

Thanks for the info trash, man that's a high launch rpm. The very first time I launched this this on the street was at about 4500 and it just sat there spinning, I've been launching at about 2300 now and get some tire spin but also propels car forward better than at higher rpms. But this is street only stuff, never been to track. Thanks again for sharing the info

DVUSz06

Thanks Stroker87, that sounds like a plan I would feel comfortable with, not comfortable with a 5k+ launch as my car is factory setup on trans&rear, no exyra brackets and factory clutch. Now after first run, how soon should I run again, meaning target water & oil temps for best performance. Thanks again for info Stroker

Stroker87

I wait about 20 minutes between runs myself, another thing to know especially if your tuned the car temp should be above 172 degrees thats when the tune changes from open to closed or closed to open dont remember just be above it like 180-190 degrees i dont run my car over 210 degrees not saying you cant i just dont

your going to want to shift FAST as you can granny shifting is going to hurt your times

the hardest part is to just relax stay focused listen to what the car is telling you and have some fun!

Trash

Remember that's where I set the rpm when staged. I hold the throttle position but NOT the rpm as the clutch is let out. By the time the clutch is fully engaged the rpm is significantly lower. When the clutch is all the way out THEN I pin the throttle. This is all typically done within about 1 car length. The higher RPM usually prevents it from bogging.

If I'm too aggressive with clutch release then yes it will spin, no doubt. I've done that too and had to pedal the throttle.

I'm not side stepping or "popping" the clutch by any means.

SVT_Z06

I feel the same way, but I get good practice!

Switching from a 28x10 to 305 45 18's drag radial this week. I'm thinking my mph might go up, as the tire size effectively changes gearing a bit. I imagine rpms would ramp up faster.

I'd be really happy with a 1.7 60ft, 7.4 @ 98 mph.

I hit 96.1 mph with an 8.0 with the slicks last time out. We shall see.

btw, I'm still running cats

SVT_Z06

New clutch, tweaked my tune and lowered tire pressure. Cut a 1.8 60 ft. and 7.6 ET, but lower mph??? Tire pressure too low maybe? This is with old 295s up front at 30 psi. I imagine this factors in somehow.

Boredom

lower mph because you hooked better, probably bogged some. You have too much tire for your setup. Go to 26s honestly. I had 28s on my full bolt on T/A and it did the same thing.. dead hooked but crappy 60 foots.

Trash

You mentioned tune. That is likely your lower MPH issue, not the 60'.

Boredom

If he lost 5mph in the 1/8th from a tune something is waaay wrong with that tune.

Trash

I agree. But I would not pin the mph loss on a better 60'. Once that event (the 60' that is) is done, it's done. MPH down is indicative of motor not accelerating through the power band as quickly as before; timing/fuel/DA are likely culprits.

SVT_Z06

It's definitely not the tune. I tuned it.

Reviewed my logs and turns out I was low on nitrous. Way too rich on wot....no nitrous.

Best mph on motor was 91 mph. Ran 94 this time. So it's making more power for sure.