Hey guys, I'm having alittle trouble getting out of the 13's, I know some of it has to do with spinning 1/2 shift and 2/3 shift. My best time is 13.3 and my best mph is 107. I have JLT/SCT93 Race tune/UDP/LT w/or hpipe/3.55 gears/5 speed. I was wondering if anybody has hit a 12.9 or better with a similar setup, and what RPM's do you recommend shifting at? I try to shift around 6000, but stay in 3rd through the traps.

 

Depends how your car pulls. Have you had it dynoed? They USUALLY pull right to 6200rpms if you have your rev limiter set to atleast 6800. Maybe try shifting there. I know with my 4:10's if I shift at 6200 I can just barely trap in 3rd gear at the rev limiter. (Mines at 7000)

Other than that your problem is most likely more to do with your 60' time and getting a good hard launch than anything else.

 

Hey Dean,
I do not drag race anymore but from reading this post you need tires, tires, and more tires. Spinning is your biggest problem it seems to me. What tires are you running. And where is your rev limiter set at. It seems to need to raise your shifting rpm.
Scott

 

You are definately spinning too much. Let me guess...you have about a 2.1+ 60ft time? Like Scott said you need stickier tires.

 

That's exactly how I ran w/ similar mods and stock rubber. You need a rubber upgrade. I need gas prices to come down so I can afford to go to the track and report the better numbers. Just w/ hard street driving, there's definitely a lot more grip.

 

That quote from Shaun is classic John!

 

Scott , I got the stock BFG's, and I have the rev limiter at 7000. I have tried shifting at several different rpms, it is just last time out I went with 6000.

Silverbossgt your right! My best 60ft is 2.112, but my best mph is 107.08, and last time I ran 106 on all runs with 106.94 2X's.

It is just a bummer having to buy tires, I would like to get 2 16" wheels and put DR or slicks on, it is just my wife and I are looking to buy a house and our budget just got really tight so we can save enough for a down payment. So for right now I can only work with what I got. Well next time out I will let the car cool longer, try shifting at 6500, and feather the shifts to try and control spinning. We'll see what happens!

 

Back when I had similar mods, MPH, and 60' times, I would run a 13.1 with 4.10's. You should be able to get a little more out of it if you adjust your shifting point. Probably going to be impossible to get to the 12's without some stickier tires though.

 

106+ mph trap speeds are indicative of a 12.90 car. If you heat (dare I say "melt") your tires before you pull up to stage (just don't back up into the water box), then you can get your 60' times down around 1.90. I've done it on my factory 235/50/18 BFG's many times. As a general rule, every two tenths you improve your 60' time should result in about three tenths improvement in your 1/4 mile ET. That should get you right at 13 flat, and maybe a 12.99 or better once in awhile. Get some drag radials and you'll be able to pull 1.80's for 60' times and you'll be running 12.90's all day.

 

You may be able to get that 60' down a little with some LCAs and relocation brackets. You could also let a bit of air out of the tires.

 

Are the LCA just for wheel hop on strait acceleration? Or do they help something else that would improve 1/4 mile time? I am fine with the way it handles on the street so I am not interested in changing something that will not help me go down the 1/4. I never had a problem with wheel hop on a launch or burn out, yet, I might if I get down to a 1.9 or 1.8 short time. I also run the BFG's at 25 psi at the track, ran 35 once and it spun even worse. Anouther problem is the HRP track is always hot when I run, we are in mid 90* wheather here in Houston so the VHT on the track is more slick than sticky untill about 1 or 2 hour after the sun goes down.

 

Hi Dean,
The weather down there for the next few months will aggrevate you to death. Not much will hook up in the conditions you will be seeing the next few months. So don't kill yourself over it.

 

I know Scott, it is just a bummer. Do you think the temp and a heat soaked engine could eat .4 a sec? I mean, I can't be that bad a driver, I was doing better than most mild moded domestics there. I just feel the car has more than what the board lights up. Good thing Houston's Raceway is open longer in the year than tracks up north, less/no snow=more practice.

 

Heat soak and hi temps in general can kill times on the top end of the track- but focus first on getting your 60' down; if you do that, then you'll be able to tell if the heat/humidity is the culprit.

 

I don't race anymore so I am not the best source to ask but I still have an opinion. And I agree completely with Tom. I known tires are out of the question now but I know they would help you so much. Even in this heat.

 

Everyone pretty much already said it all...But that 107 trap is good for 12s, so I'd recommend SEAT TIME!

 

If you're going to try shifting at 6500 (I'd suggest 6400) Then raise your limiter to atleast 6900-7000.