My car got slower
#1
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My car got slower
My F completely stock ran the 1/4 mile at 12.8 @ almost 112 mph. A year later I added a Joe Z intake pipe and ISS DES Exhaust and ran a 12.6 @ 113 (March '12). Last week I headed back to the track and the car will not break into the 12's. I'm running 13.0-13.2 @ 109-110 mph. My 60' times are still the same ~2.0, Sport mode, Trac/VSC off, I'm paddle shifting at the beep. I lost 3 mph in the 1/8th and 3-4 mph in the 1/4. I thought it was bad fuel so I ran it down and got a 1/2 tank from Sunoco 93. I even reset the ECU. Headed back to the track a few days later and same results. Looking for some ideas on what could be the issue
Here are a couple of vids stock and after intake/exhaust.
Here are a couple of vids stock and after intake/exhaust.
#2
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There are a lot of factors that go into these 1/4 mile runs. Weather, temperature, humidity, etc and even driver skill. No offense!
Seeing how you ran it earlier in the year it was bit cooler I'm assuming. If that's the case it may be a little warmer last week than your last run so that's something to keep in mind.
If you really want to find out if you're actually losing power, try running your car stock and again with the mods to have a better benchmark.
Seeing how you ran it earlier in the year it was bit cooler I'm assuming. If that's the case it may be a little warmer last week than your last run so that's something to keep in mind.
If you really want to find out if you're actually losing power, try running your car stock and again with the mods to have a better benchmark.
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Both March and September were both cool days in the 50's low 60's. I don't think it was enough to lose 4 tenths from stock. I understand the Joe Z gets very warm. Maybe I'll try going back to stock. I had about 30-45 min between runs. Spare is out of the car. I'm running Mickey Thompson Street ET's. I'll probably get it back on the dyno to see if there was any hp loss.
#7
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Weather is most likely the culprit. With the same setup but in different weather conditions (density altitude) I've run anywhere between 11.9 and 12.5. Check the weather history for the days you were at the track and calculate the DA to see for yourself.
PS even on a dyno you won't be able to tell much as you'll also get varying results on a day to day basis. Obviosly if the results are way off then you may have something to go on.
PS even on a dyno you won't be able to tell much as you'll also get varying results on a day to day basis. Obviosly if the results are way off then you may have something to go on.
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#8
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Weather matters more than just the degrees. Honestly with DR's you should be cutting at least 1.9 60' if not 1.8s.
Anyway. I would drive it for a couple weeks if you reset the ecu. I always got good results from using sport mode when I was actually hauling *** around, not stuck in traffic going nowhere. I dont know for certian what sort of learning the ecu does on/off of sport mode, but I do know I always posted good-great times everytime I went out.
~Dv8
Anyway. I would drive it for a couple weeks if you reset the ecu. I always got good results from using sport mode when I was actually hauling *** around, not stuck in traffic going nowhere. I dont know for certian what sort of learning the ecu does on/off of sport mode, but I do know I always posted good-great times everytime I went out.
~Dv8
#9
Check the BAROMETRIC PRESSURE. I've cut 2.0 and down to 1.8xx completely depending on the pressure. That's with MT and low weight. My best was 12.3 and recently did a 12.8 and the only difference was barometric pressure.
Everytime I go drag racing now, I check to see if the barometric pressure is 30.2 inches or higher. If it's like 29.8 inches I'm only going to hit 12.7-.8 I ran my 12.3@30.4
Everytime I go drag racing now, I check to see if the barometric pressure is 30.2 inches or higher. If it's like 29.8 inches I'm only going to hit 12.7-.8 I ran my 12.3@30.4
#10
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You guys are probably on to something. The DA in March when I ran was -822 and when I ran last week it was 553. Barometric Pressure was 30.24 vs. 30.10. Temp was 51 vs 65 degrees.
DV8 - I still can't figure out what RPM to launch this car. I've tried off idle upwards to 3000 RPM and can't get this thing to take off. I'm running tire pressure as low as 20 psi to 30 psi. I also took cayman's advice of burning out to the top of 2nd gear.
DV8 - I still can't figure out what RPM to launch this car. I've tried off idle upwards to 3000 RPM and can't get this thing to take off. I'm running tire pressure as low as 20 psi to 30 psi. I also took cayman's advice of burning out to the top of 2nd gear.
#13
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You guys are probably on to something. The DA in March when I ran was -822 and when I ran last week it was 553. Barometric Pressure was 30.24 vs. 30.10. Temp was 51 vs 65 degrees.
DV8 - I still can't figure out what RPM to launch this car. I've tried off idle upwards to 3000 RPM and can't get this thing to take off. I'm running tire pressure as low as 20 psi to 30 psi. I also took cayman's advice of burning out to the top of 2nd gear.
DV8 - I still can't figure out what RPM to launch this car. I've tried off idle upwards to 3000 RPM and can't get this thing to take off. I'm running tire pressure as low as 20 psi to 30 psi. I also took cayman's advice of burning out to the top of 2nd gear.
~Dv8
#14
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FWIW.... I recently changed my battery on the IS-F.. The + & - terminals were unplugged for 3 days.
From time to time I like resetting my ECU, using the Fuse Pull procedure.
I have also done it by disconnecting the battery for a few minutes..
BUT this time I noticed a major difference in how the car responds and how it launches.. I feels like it did when I first bought it.. Plus the extra kick from the performance parts...
Try leaving the battery disconnected for a longer period.. or as long as you can...
Just my .02 cents
~ Joe Z
From time to time I like resetting my ECU, using the Fuse Pull procedure.
I have also done it by disconnecting the battery for a few minutes..
BUT this time I noticed a major difference in how the car responds and how it launches.. I feels like it did when I first bought it.. Plus the extra kick from the performance parts...
Try leaving the battery disconnected for a longer period.. or as long as you can...
Just my .02 cents
~ Joe Z
#15
Lexus Champion
Though there are many differences in comparison from a top fuel nitro dragster and a street car, I follow the NHRA Drag Racing Series and those guys that run Top Fuel, Funny Car, etc, these guys are obviously extremely talented and very skilled and have pretty deep pockets, and those guys from time to time will run different times.
Track setup, weather conditions, engine maintenance (1 year later), we don't know how the condition or specs of the internals of your car. However, given all things the same, like someone mentioned, it could very well come down to track prep as well. I've seen at some NHRA events where the different lanes weren't prepped the same. Considering that, depending on which track you went to and the budget that's put in place for track setup, could be something that was skimpped on.
Track setup, weather conditions, engine maintenance (1 year later), we don't know how the condition or specs of the internals of your car. However, given all things the same, like someone mentioned, it could very well come down to track prep as well. I've seen at some NHRA events where the different lanes weren't prepped the same. Considering that, depending on which track you went to and the budget that's put in place for track setup, could be something that was skimpped on.