Why is my MPH so low??
Thread Starter
Instructor
Joined: Jan 2003
Posts: 242
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From: Dallas TX
Why is my MPH so low??
in my '95 C4 auto, bone stock w/ only bullet mufflers, my best was a 13.6@99 w/ a 2.0. the car only has 40k miles. This was like this past May, around 80* weather, if that matters...
After checkin the forums out for a little while, it seems that most are runnin' 101+. The car feels strong, the e.t. was pretty good I thought, but the mph just seems low. just seeing if there's any kind of explanation for this..
After checkin the forums out for a little while, it seems that most are runnin' 101+. The car feels strong, the e.t. was pretty good I thought, but the mph just seems low. just seeing if there's any kind of explanation for this..
Race Director
Joined: Oct 2001
Posts: 19,653
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From: Melbourne Florida
Cruise-In IV Veteran
Re: Why is my MPH so low?? (red95vette)
13.6 is a good time for stock...did you have the ASR off ?....did you race it in 3rd or 4th gear ?....did you stay at WOT till about 60' past the finish line ?...
Thread Starter
Instructor
Joined: Jan 2003
Posts: 242
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From: Dallas TX
Re: Why is my MPH so low?? (Fuzzy Dice)
I had ASR off and I believe I had the car in D (3rd) instead of OD. I think there was a light that changed colors when you went through the traps... so i usually stopped when that changed. I'm pretty sure I was on it all the way through the traps. I pulled like 5 consistant 99 mph's...
Race Director
Joined: Sep 2000
Posts: 17,298
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From: The Top of Utah
Re: Why is my MPH so low?? (Fuzzy Dice)
Fuzzy Dice,
Are you living in the past? It used to be that the mph trap was from 66' before the finish line to 66' beyond the the line. Years ago, they eliminated the "speed off" timer, 66' past the 1320. Your mph is now measured from 66' before the 1320 to, the 1320. Nothing past the finish line counts for anything, any more. I hope I didn't take your, "did you stay at WOT till about 60' past the finish line ?...", comment wrong. Good luck, and...
RACE ON!!!
Are you living in the past? It used to be that the mph trap was from 66' before the finish line to 66' beyond the the line. Years ago, they eliminated the "speed off" timer, 66' past the 1320. Your mph is now measured from 66' before the 1320 to, the 1320. Nothing past the finish line counts for anything, any more. I hope I didn't take your, "did you stay at WOT till about 60' past the finish line ?...", comment wrong. Good luck, and...
RACE ON!!!
Elite Torch Red Member
Joined: Sep 1999
Posts: 57,805
Likes: 23
From: Exit 89 GSP,Lakewood,NJ The Land Of Mojo
Cental/South NJ Events Coordinator
CI 1-2-3-4-5-6-7-8-9-10-11-12 Vet
CI-II Burnout & Drag Champ
St. Jude Donor '03-'04-'05-'06-'07
Re: Why is my MPH so low?? (CFI-EFI)
Your mph should at least be 103-105.
This goes to a topic we've discussed many moons ago. It's called adaptive learning, the PCM learns how you drive your car and calibrates itself to run that way or something like that, I'm no expert. But it made sense because I was racing my car every weekend for two years straught before I started racing another car and my mph was always 107-108.
Garage queens tend to run more poorly than daily drivers. With 40k on the clock, your car has hardly been driven. Start racking up the miles and drive it hard, you may see an improvement. This is of course assuming all else is welll(state of tune etc.)
This goes to a topic we've discussed many moons ago. It's called adaptive learning, the PCM learns how you drive your car and calibrates itself to run that way or something like that, I'm no expert. But it made sense because I was racing my car every weekend for two years straught before I started racing another car and my mph was always 107-108.
Garage queens tend to run more poorly than daily drivers. With 40k on the clock, your car has hardly been driven. Start racking up the miles and drive it hard, you may see an improvement. This is of course assuming all else is welll(state of tune etc.)
Thread Starter
Instructor
Joined: Jan 2003
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From: Dallas TX
Re: Why is my MPH so low?? (Mr Mojo)
that's odd
I do drive it harder than it has previously been driven all it's life. It feels just as strong, if not stronger since i've had it. I'm the only person who's really pushed this car much.
during that 13.6 run, it put down an 8.8@81.9 in the 1/8, which seems like good mph that would net me over 100+ in the 1/4. and a month or 2 after that run, I went to an 1/8 mile track in 95*+ weather (it was hot as hell that day)... and pulled an 8.8@80 w/ a 2.1, which seems weird comparing the two times. only change was a cut airbox.
the car doesnt stutter, seems to mechanically run fine, but maybe I should look into replacing plug/wires, and a little tune-up??
I do drive it harder than it has previously been driven all it's life. It feels just as strong, if not stronger since i've had it. I'm the only person who's really pushed this car much.
during that 13.6 run, it put down an 8.8@81.9 in the 1/8, which seems like good mph that would net me over 100+ in the 1/4. and a month or 2 after that run, I went to an 1/8 mile track in 95*+ weather (it was hot as hell that day)... and pulled an 8.8@80 w/ a 2.1, which seems weird comparing the two times. only change was a cut airbox.
the car doesnt stutter, seems to mechanically run fine, but maybe I should look into replacing plug/wires, and a little tune-up??
Elite Torch Red Member
Joined: Sep 1999
Posts: 57,805
Likes: 23
From: Exit 89 GSP,Lakewood,NJ The Land Of Mojo
Cental/South NJ Events Coordinator
CI 1-2-3-4-5-6-7-8-9-10-11-12 Vet
CI-II Burnout & Drag Champ
St. Jude Donor '03-'04-'05-'06-'07
Re: Why is my MPH so low?? (red95vette)
cut airbox won't do much if anything.
My best 1/8 mph was 85.
My best 1/8 mph was 85.
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Thread Starter
Instructor
Joined: Jan 2003
Posts: 242
Likes: 0
From: Dallas TX
Re: Why is my MPH so low?? (Mr Mojo)
maybe your cats are clogged. I know the mileage is low but you never know.
cut airbox won't do much if anything.
My best 1/8 mph was 85.
My best 1/8 mph was 85.
Elite Torch Red Member
Joined: Sep 1999
Posts: 57,805
Likes: 23
From: Exit 89 GSP,Lakewood,NJ The Land Of Mojo
Cental/South NJ Events Coordinator
CI 1-2-3-4-5-6-7-8-9-10-11-12 Vet
CI-II Burnout & Drag Champ
St. Jude Donor '03-'04-'05-'06-'07
Re: Why is my MPH so low?? (red95vette)
try and get your oil and coolant temps down and you should see a noticable difference
Race Director
Joined: Oct 2001
Posts: 19,653
Likes: 428
From: Melbourne Florida
Cruise-In IV Veteran
Re: Why is my MPH so low?? (CFI-EFI)
No, I'm not living in the past.. :lol: ..I just wrote it poorly...a lot of "now and then" racers sometimes think they are at the finish line when they are actually a bit short of it...they lift and don't get full value...had a guy last Saturday that was misjudging the line...I told him to stay in it a bit longer and his MPH went up by 3 MPH... :thumbs: ...not the case here apparently...
Instructor
Joined: Jun 1999
Posts: 182
Likes: 1
From: oak island NC
Re: Why is my MPH so low?? (Fuzzy Dice)
Dirty cats,, dirty air filter...tire pressure too low..and excessive burn on the start will affect your mph. What are your 60' times? Possibly your knock sensor is kicking in. What are your rpms when you cross the line ?
Race Director
Joined: Sep 2000
Posts: 17,298
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From: The Top of Utah
Re: Why is my MPH so low?? (Fuzzy Dice)
Fuzzy Dice,
It sounds like your guy might have thought the mph "on" line was the finish. Since your 60' number was so close to that old distance, I thought, maybe... I'll bet there are a few on the forum that don't remember the old 128' mph trap. Good luck, and...
RACE ON!!!
It sounds like your guy might have thought the mph "on" line was the finish. Since your 60' number was so close to that old distance, I thought, maybe... I'll bet there are a few on the forum that don't remember the old 128' mph trap. Good luck, and...
RACE ON!!!
Thread Starter
Instructor
Joined: Jan 2003
Posts: 242
Likes: 0
From: Dallas TX
Re: Why is my MPH so low?? (ncChris)
Dirty cats,, dirty air filter...tire pressure too low..and excessive burn on the start will affect your mph. What are your 60' times? Possibly your knock sensor is kicking in. What are your rpms when you cross the line ?
Burning Brakes
Joined: Feb 2003
Posts: 1,246
Likes: 1
From: SouthBend IN
Re: Why is my MPH so low?? (red95vette)
sounds like detonation to me.
Do you know if it has a chip in it ?
i think you can down free scan at no cost and monitor the car to see what's going on on a pass down the track. Check the plugs ( with a magnifying glass) look for detonation. Also if you see any then try some 100 octane leaded fuel as a comparison run.
Good Luck
Do you know if it has a chip in it ?
i think you can down free scan at no cost and monitor the car to see what's going on on a pass down the track. Check the plugs ( with a magnifying glass) look for detonation. Also if you see any then try some 100 octane leaded fuel as a comparison run.
Good Luck
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Re: Why is my MPH so low?? (mike 1985)
Also if you see any then try some 100 octane leaded fuel as a comparison run.
Good Luck
Good Luck
RACE ON!!!
Burning Brakes
Joined: Feb 2003
Posts: 1,246
Likes: 1
From: SouthBend IN
Re: Why is my MPH so low?? (CFI-EFI)
oops, i meant unleaded 100 octane. Although you can run quite a bit of leaded gas through before problems can occour. I believe the o 2's will take 50 hrs and i've never heard of a cat failure with leaded gas.
One guy here uses leaded 112 octane for 2 yrs ( at the track only) now on his lt-1 and hasn't had a problem yet.
good Luck
One guy here uses leaded 112 octane for 2 yrs ( at the track only) now on his lt-1 and hasn't had a problem yet.
good Luck
