so the people in the performance section and fellow texas IS owner's know I have made some mods that increased my performance. Well I went from being happy about running 8.8's in the 1/8th mile to 8.7's. Then mods came and started hitting 8.5' and 1/4 @ 13.32. Great!

well, now i have double the miles on my car I did 2 months ago and it (in theory) should be getting faster as the car breaks in. Well sunday i ran 1/8th mile at 8.8 and 8.9. I was pissed so i left. I went back tonight with good bp, nice dry cool temps. I could not run anything better then 8.7. I had just 1/4 tank of gas , no spare and no engine covers. The funny thing is that my 60' time is awesome for stock tires. like 2.00 60's. However, my trap speed is 2 to 3mph slower then when my car was stock.

Just pissed. Not sure what to think about the slower trap speeds. OH well , just *****ing.

 

More weight in the back may not be a bad idea. It should give you better traction. Try with the spare tire in the car.

 

Interesting. Buying your gas at the same place? Maybe the oil companies are changing the mix (like % of ethanol, or other additives) of the gas for Summer? Judgeing from the 2.0 60', it's not the track or your tread.

 

DJ Amtrax. My 60's are great so I am hooking up well at the rear wheel

cws: I am thinking that is what it could be. Maybe the summer gas mix? I didn't buy gas at the same place. OH well. maybe it's time to go back to the drawing boards and see what else I can do exhaust wise without making it all loud.

 

Lower mph means less hp. End of story. Lots of possible reasons, but all this BS about break in and getting faster is just that: BS. You're not driving a domestic with hypereutectic pistons and a cast crank. It isn't going to get better as the miles roll on. It might be fuel, it might be ring wear, it might be air pressure, it might be a lot of things, but for sure it is less hp. MPH never lies.

Imagine how I felt last week at 9.0 and 81.x mph...

 

how's your tire condition?

 

How many miles are on your car now anyways? just curious-

 

My car is the same way, I trap over 103 when I was stock. NOw I have a joez intake and I can barely trap 103. I still haven't been able to duplicate my best of 13.49 after adding the joez. My 60' also got better too, they are usually in the 2.0X, the stock dunlops seem to hook very well when bald for some reason. They were usually in the 2.1x when they were new. It seem like caymandive's car is the only car that run consistent. My car been running 13.5 all the time lately but I still haven't been able to beat my best of 13.49 back then when I was stock, arh the frustration.

 

lobuxracer is right... The car will not break in "more" and get faster with higher miles....

I am going to specifically prove it on my IS350 when my car hits 5000 miles too... As I dynoed my car with less than 1000 miles on the ODO, and I will dyno it again (at the same place) with 5000 miles (fully "broken in")... I have made no performance mods, so the car was stock for the first dyno run, and will be stock for the next dyno run... I bet the numbers will not change at all...

Stay tuned for another episode of mythbusters featuring my car as the guinea pig...

 

I don't see how you guys can say that the car doesn't make more power after a few thousand miles. My car is MUCH more powerful now than it was a year ago. When my car was new, I couldn't even make my rear tires "chirp" without torque braking. Now, I can't even go full throttle in 1st gear without breaking loose, and I can chirp 2nd gear all day long. Before people start blaming my tires ... they are new.

 

are you driving in automatic mode? maybe it's your learning computer adjusting itself to your driving habits when you're not running it hard?

 

Comb,

I would try getting to the track with as little gas as possible, then buy a few gallons of race gas from the track. Of course, you should probably then reset your ECU and drive around for 10-20 miles before racing.

 

Have you been eating too much fast food in past 2 months?
just kidding

Do you drive in PWR mod all the time? I felt that my car goes faster when I switch between PWR and Normal rather than at PWR all the time. May be ECU reset as Grenby said would help.

 

Track conditions can also be a factor.

 

Different days, different conditions. Plus just because its a track doesn't mean the timers are perfectly accurate everytime.

Could be slower, the same, or faster on any given day. Not really a big deal worrying about tenths of a second unless you are a professional racer.