I found the following equation on the internet (so it must be correct )

234 * (HP / Weight) ^ .3333 = mph


396 HP, 3420 lbs = 114.1 mph
350 HP, 3420 lbs = 109.5 mph
333 HP, 3420 lbs = 107.7 mph

 

Well I went to the track a few weeks ago in full street trim (20s all round) to see what it can do, I was told off last time for not having a battery holder so on the day I disconnected my battery and fitted a battery holder. I drove about 60miles to the track and my first 2 runs were 12.7xxx my third was 12.5 and I finished with a 12.44 BUT in saying that my mph was 110 when I got my 12.31 my mph was nearly 113.

Bob one way to check for sure is to take it to a dyno that was the same as when you got your reading and see if your getting similar figures. If there's a 20-30hp drop then you know something wrong.

 

Yes it is your DA. Running in very low DA that you were able to set your personal best at is very lucky and deceiving at the same time. I've stressed in the past how important it is to pay attention to the DA on every pass. As you can see from Mke's post the DA changed on every pass. With enough passes and consistency on your part as a driver, i.e. similar mods, launches, tires, etc.. you will be able to predict your ET within 3 hundredths of a second. Yesterday at a local shootout I ran 12.40, 12.399, 12.393 in qualifying. Eliminations broke out with a 12.379 on a 12.39 dial, then bought back in and broke out again with a 12.367 on a 12.37 dial. The DA fluctuated from 3890' up to 4400', and my car was a half second slower than my personal best. Was I worried, not in the least. Once you have enough data on your car you will know how much .01 you will add to your personal best baseline for every 100' DA is higher than the 250'. My best was at 1400' DA and just over 2000' difference slowed mine a half second. I did use the stock conti's yesterday and soft launched, so I lost maybe a tenth. Still my Performaire PA2 was dead on with my prediction after adjusting for the tires. I'd recommend to check the weather for your next event, use a DA calculator online to get an idea of what you may run.

Sidenote: MikeR are you kidding me? Negative DA and you wasted it on an 11.96. Just send in your ECU to Washington to ummm some tuner there and get your 11.7 already.

 

bob like i said on the fone its the weather. cruzinquick i believe nailed it. the guys out west get absolutely killed with the heat for racing. you had a massive storm coming in and the weather beat you bad.
the car is fine and ill bet you a cold glass of tea next week you and i run within .1 of each other. whether the times are low 12's or high 12's we will be so close it will be worth the price of admission!
side note: i looked at the pre-register and not a single rwd!! could you and i be the only ones? what a day that would be!!!

 

Cruzin is spot on with his explanation....minus that whole Washington thing. LOL. I just say this after seeing 240M3SRT switch from one tune to the other and saw no increase in performace what so ever!!!

Dont worry Bob!

 

Thanks guys.... I guess it is my inexperience that had me concerned. We will see what happens this coming weekend. Oh, and Steve... We may be within .1 of each other next weekend if your lucky.... But after we finish, let me know what my exhaust sounds like OK. And, you had better nail your launch also if I hit them like I did on Friday. JK.... We should be pretty close to each other. I ran against Alan 2 times Friday. He had slightly faster times than me. The first run, he ran out of room to reel me in as I beat him off the line. The second run, I beat him off the line again, but he reeled me in and beat me by about half a car.

Also, to give Alan credit, he was not doing any burnouts, and was not launching as hard as he normally would. He is still gun shy of the differential..... With good reason. I must admit, that I was a bit leery of doing burnouts myself.

 

reiterating everyone elses comments, Humidity is hell on these cars as they can't breath the dense air. You would be amazed at the difference just 5 or 10% will do to your times. I wish I had things in order to meet the three of you at the import showdown, and to beat Steve as I have heard about our last meeting for 6 months now, lol. I can't wait til it is a bit more level fielded. Good luck with your findings, and at the showdown. Give em hell!!!

 

Well, either I will be giving Steve hell for the next 6 months, or he will be so busy ragging me that he will forget about razzing you. I have been told that my exhaust sounds like a jet engine going down the track. Maybe Steve can confirm that. LOL

 

I'm proof to tonight that DA has nothing to do with it. I'm in the lanes waiting to start my 3rd run and so far I've got two 12.8's and it's freezing outside.

I'm really starting to think my tune is gone

 

Define freezing... I spent 18 months in Northwest Cape and freezing was..like 70°....

Sorry to hear you are still having probs.....

 

Hey Mike it was about 45 degrees, but by being cold I thought the car would build more boost and go harder

I emailed InMotion and they said that even though I may not be noticing it the car (because of the cold track) might still be slightly loosing traction meaning the ESP and stability control and slowing the car down. Im not sure if thats true or not but I sure hope so


Sorry to hijack your thread Bob, but it seems were having similar problems!!

 

Do you data log? I ask because I installed a code3 pulley and went slower, then I got a data logger and found out the car was shifting early from 1rst to 2nd and 2nd to 3rd. And the reason was the tires started slipping when the car entered the power band and the (I assume ESP and traction control) made the transmission shift at 4500 rpm. You can't go faster if you never get into the power band. The last time at the track I ran a bunch of 15's at 109. (I have lots of negative camber at the moment) If you can rig a camera to watch the dash you might see the traction control light flashing, which will confirm what I'm suggesting.

Les

 

Hey Les I have my traction control off when I drag race, but InMotion said stability control will still be slowing me down.

Interesting thing that you said though, my car shifted to 3 gear before I was even at half track which is really wierd, its never done that before so maybe you and InMotion are on to something, car shifting earlier when its losing traction.

 

I always race with traction control off but it is never all the way off. The car will upshift with traction control "off" instead of cutting the power like it does with it on unless you get really, really out of shape. I found out what was going on because of my data logger. Then I did some tests to verify. If you can, watch for the traction control light. With traction control turned off it will flash 2 or 3 times and then upshift if the tires are loosing traction. Perhaps it's stability control and not traction control but the result is an early upshift and a slow time.

Les