I guess my best approach at this point will be to switch to "excuse elimination" If I one by one pick off the open concerns, then the correct result should only be left. I'll hit the track tomorrow and hope for some answers.
Thanks for the input Lud
More 1/4 mile stuff
- Thread starter McAttack
- Start date
I guess my best approach at this point will be to switch to "excuse elimination" If I one by one pick off the open concerns, then the correct result should only be left. I'll hit the track tomorrow and hope for some answers.
Thanks for the input Lud
Hope I get the chance to meet the man behind the emails down the road.......
You can redline before 130mph in 4th gear w/ a stock 6-speed... If the rear tires have a diameter smaller than stock!
With McAttack running 285/30/18's, I think that results in a slightly smaller diameter than the stock rears (245/45/17's if memory serves).
But that really doesn't take anything away from the point you were trying to make however.. Something is wrong. I have a stock 6 speed and run 285/30/18's as well and I'm into the 120's before I'm thinking about shifting. No way McAttack should be redlining at 114mph unless those are 285/30/16's or something
Marc
The're 285/30/18's. Virtually the same diameter as stock tire and wheel. Didn't go to the strip yesterday (just didn't seem right) Will try my luck tomorrow night.
I guess you could say I've been down the track once or twice! (Read Honda tuning magazine page 92) I've run into all sorts of problems. The Simplest things you'd never expect have happened.
One of my problems was - I FORGOT to open the nitrous bottle. Runs the engine rich and slows it down.
Another problem was that I had a friend mount the bottle for me (Switch out to a full bottle) between races while I checked on the schedules. He just sat it in the trunk. There's a siphon tube that points in a SPECIFIC direction. even though the bottle was full, I didn't get any nitrous into the system because the siphon was pointing into the only part of the bottle that was air, not nitrous. Which brings me to another point. Are you sure you're just not running out of nitrous?! You can heat up AIR to have the bottle at 900-1100psi, but it's just air, not nitrous.
I'm going to have to say no way on the tires effecting much. I ran 10.5" slicks with a 26.5" diameter. Large and in charge, my time slips did not drop even when using my smaller 100 shot. (got faster because of more traction) So, no real drag there. ALWAYS make sure your TCS is off. It will kill your times. You should be running 118 without nitrous. I just don't understand!
My car Totally stock 91 with a 100 shot Stock tires 12.4 @ 116mph Drag slicks 12.3 @115mph. With your six speed and supercharger and more stock horsepower how can you be running slower?! - I do speed shift which may shave a few tenths, but none the less speeds should be up for you - especially looking at your dyno. Great power all the way through.
Check your boost. Make sure the bypass valve is working. What else?
Good Luck!
Bruce Karger
Autologic Inc.
[email protected]
One of my problems was - I FORGOT to open the nitrous bottle. Runs the engine rich and slows it down.
Another problem was that I had a friend mount the bottle for me (Switch out to a full bottle) between races while I checked on the schedules. He just sat it in the trunk. There's a siphon tube that points in a SPECIFIC direction. even though the bottle was full, I didn't get any nitrous into the system because the siphon was pointing into the only part of the bottle that was air, not nitrous. Which brings me to another point. Are you sure you're just not running out of nitrous?! You can heat up AIR to have the bottle at 900-1100psi, but it's just air, not nitrous.
I'm going to have to say no way on the tires effecting much. I ran 10.5" slicks with a 26.5" diameter. Large and in charge, my time slips did not drop even when using my smaller 100 shot. (got faster because of more traction) So, no real drag there. ALWAYS make sure your TCS is off. It will kill your times. You should be running 118 without nitrous. I just don't understand!
My car Totally stock 91 with a 100 shot Stock tires 12.4 @ 116mph Drag slicks 12.3 @115mph. With your six speed and supercharger and more stock horsepower how can you be running slower?! - I do speed shift which may shave a few tenths, but none the less speeds should be up for you - especially looking at your dyno. Great power all the way through.
Check your boost. Make sure the bypass valve is working. What else?
Good Luck!
Bruce Karger
Autologic Inc.
[email protected]
I called Comptech yesterday and spoke at length with Shad. My mechanic lent me the SnapOn Meter thing that plugs in under the glove box. All the numbers were in line w/ what shad said. Also checked the Map Hg which was exactly at 29.9% under full boost and no more than this at 8000 RPM confirming the CT ESM is doing its job.
Shad also mentioned the bypass valve. My mechanic checked it a while back and it was fine. I am going to adjust the A/F on the reg a bit since the dyno showed it is running a tad lean. RE The nitrous. I was told if you are not getting nitrous, YOU KNOW. Not exactly sure what my mech meant. I will have the bottle topped off to be sure. Glad to hear about the tires not mattering as I'm inherently too lazy to change them. Will put them to 20PSI. Extras out of the car and as little Sunoco 94+ PLUS 104+ Octane Boost in the tank as possible. Bummed to hear the power shifting is only good for a few 10ths. I was hoping it would be more.
Going tomorrow morning....wish me luck!
Shad also mentioned the bypass valve. My mechanic checked it a while back and it was fine. I am going to adjust the A/F on the reg a bit since the dyno showed it is running a tad lean. RE The nitrous. I was told if you are not getting nitrous, YOU KNOW. Not exactly sure what my mech meant. I will have the bottle topped off to be sure. Glad to hear about the tires not mattering as I'm inherently too lazy to change them. Will put them to 20PSI. Extras out of the car and as little Sunoco 94+ PLUS 104+ Octane Boost in the tank as possible. Bummed to hear the power shifting is only good for a few 10ths. I was hoping it would be more.
Going tomorrow morning....wish me luck!
If it was me, I wouldn't be too worried about nitrous / boost / tire pressure / etc.. until I figured out why I am getting to redline in fourth way too soon.
You need to do some simple tests before taking the car out to the track again. Get a friend to sit in the passengers seat with a paper and pencil. Put the car in first gear drive up to 4000rpm and record the MPH, then do the same thing in each gear. With this information we can calculate your gear ratio's and see if you have standard or modified gearing. It might also let us know if your clutch is slipping at the track, because at 4000rpm if you do it gradually you shouldn't see any slip and get the true gear ratio.
I did some testing on my '00 to give you a baseline of a stock car in the first four gears:
1st Gear @ 4000rpm 20mph
2nd Gear @ 4000rpm 37mph
3rd Gear @ 4000rpm 50mph
4th Gear @ 4000rpm 65mph
So you can see you would need to be going 130mph to have to shift into fifth.
Please keep us posted on your results.
Good Luck!
[This message has been edited by Carguy! (edited 13 September 2002).]
You need to do some simple tests before taking the car out to the track again. Get a friend to sit in the passengers seat with a paper and pencil. Put the car in first gear drive up to 4000rpm and record the MPH, then do the same thing in each gear. With this information we can calculate your gear ratio's and see if you have standard or modified gearing. It might also let us know if your clutch is slipping at the track, because at 4000rpm if you do it gradually you shouldn't see any slip and get the true gear ratio.
I did some testing on my '00 to give you a baseline of a stock car in the first four gears:
1st Gear @ 4000rpm 20mph
2nd Gear @ 4000rpm 37mph
3rd Gear @ 4000rpm 50mph
4th Gear @ 4000rpm 65mph
So you can see you would need to be going 130mph to have to shift into fifth.
Please keep us posted on your results.
Good Luck!
[This message has been edited by Carguy! (edited 13 September 2002).]
Have you done anymore testing?
Well, I did NOT go to the track this past weekend. Since I'm attending the NE NSX 2002 Ralley in NH this weekend, my wife reminded me we would look pretty stupid if of the 26 attendees, we were the only ones in a minivan. Looks like the 25th. BUT, I did get a chance to check my speeds at 4000 rpm. They are:
1st - 24 mph
2nd - 38 mph
3rd - 50 mph
4th - 64 mph
5th - 79 mph
6th - 100 mph
Factor margin for error and they are identical to yours. My tire size being 285/30/18 makes it a hair off but I'm convinced my gears are stock. Checked my NOS and still have 1200 lbs of pressure too.
Maybe I'll learn something in NH this weekend. 26 heads are better than one.
Remember, just because your bottle pressure is at 1200psi, it doesn't mean you have any nitrous. Do yo have a bottle warmer? The best way is to pull the bottle and weigh it. Anything over 14.5 lbs is nitrous (Unless you measure it with a warmer and bottle opener still attached)
One big thing that everyone has overlooked is that you running at a track in New Hampshire. Altitude has a huge effect on HP combined with the hot temperatures and the humidity, would easily cause your car to run slower then a sea level track. Hope that helps.
Your 4k readings suggest stock gearing, so how is it that you need to shift to 5th if 4th should be good to ~128? I previously dismissed the idea of a slipping clutch and still don't believe it's likely, but we're running out of possibilities.
Darn, I was just in Boston last Saturday and should have stopped by before the LONG drive home.
Darn, I was just in Boston last Saturday and should have stopped by before the LONG drive home.
I did pull it to have it filled. The guy who fills them measured the PSI. He also gave me and empty one vs mine. Mine is at least half full.
The "slipping clutch" theory seems to be gaining more and more favor. Hopefully some of the "more seasoned" owners will have added ideas when I see them at NE NSX 2002 in NH this weekend.
A slipping clutch is very easy to detect, even if you don't smell it. If engine speed (RPM) raises more quickly than suggested by the rate of acceleration, then something is slipping. That something can only be tires or clutch. (or rims inside the tire like a real drag car) Do you have any sense of this when you run it hard?
The amount of slip necessary to cause your case would be enough that you should be able to cruise along at 4k in 2nd or 3rd gear, press the clutch in, rev the engine about 1500 and dump the clutch back out while giving it full throttle. If it slips rather grabbing solidly then you have problems.
This should be done by someone who knows how to do it correctly to avoid unnecessary wear or other damage. But I still get back to the launch. If it grabs hard off the line and spins the tires from a dead halt, then it should not start slipping on the shifts.
The amount of slip necessary to cause your case would be enough that you should be able to cruise along at 4k in 2nd or 3rd gear, press the clutch in, rev the engine about 1500 and dump the clutch back out while giving it full throttle. If it slips rather grabbing solidly then you have problems.
This should be done by someone who knows how to do it correctly to avoid unnecessary wear or other damage. But I still get back to the launch. If it grabs hard off the line and spins the tires from a dead halt, then it should not start slipping on the shifts.
Things I dismissed on my last trip to the strip I'm thinking on now and have to wonder. For example, "not moving" off the line.....slipping clutch or spinning wheels? I don't know. I am however sure to find out this weekend.
What gets me is that the clutch (a CompTech PowerGrip II w/only has about 3500 miles on it) can run fine as a daily driver but slip under heavy stress.
Shouldn't/wouldn't it have shown itself on my daily commutes by now? Never heard of this "selective slipping" but as I said, I should know more this weekend.
A BIG THANK YOU to everyone who posted. Your knowledge and advice is greatly appreciated.
What gets me is that the clutch (a CompTech PowerGrip II w/only has about 3500 miles on it) can run fine as a daily driver but slip under heavy stress.
Shouldn't/wouldn't it have shown itself on my daily commutes by now? Never heard of this "selective slipping" but as I said, I should know more this weekend.
A BIG THANK YOU to everyone who posted. Your knowledge and advice is greatly appreciated.
The odds of the tach being off and getting the same mph numbers @ 4000rpm as stock gearing is remote. Also he stated that the rev limiter kicked in on a couple of shifts so it sounds like the tach is fine.
My money is betting on a clutch that is slipping. There isn't anything else I can think of that would cause the car to redline in 4th gear with the current gearing.
I'm kind of paranoid at this point on this. It's like the med student who comes down with the latest illness he is studying that week. I seem to be feeling "slipping effects" since you brought this thought up. Should know for sure this weekend.
If your clutch was slipping, you would smell it after your run. Its the same smell as buring brake pads.
I listed this in another related post but FYI, turns out my car was running way rich plus one of my plugs may have been out. Replaced all the plugs, had the A/F adjusted, went to the strip and.......1/4 mile WITHOUT having to shift to 5th.
Let another NSX owner (Larry Bastanza) drive my car this past weekend. "The clutch is fine." and the gears are stock too.
How could a bad plug and running rich do this? Who knew?
Let another NSX owner (Larry Bastanza) drive my car this past weekend. "The clutch is fine." and the gears are stock too.
How could a bad plug and running rich do this? Who knew?
A bad spark plug and running rich would not make you car redline in 4th requiring a shift into 5th. If anything it would be running at a lower RPM in 4th that if the car was generating more power. I am glad the car is running better though
One run only after 90 minutes waiting. 12.9
DON'T SAY IT!!!!
I'm going back next week when it's less crowded
This has got to be an unrelated overlap. Both did happen but does not necess mean one caused the other.
Stay tuned...
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