4.6L General Discussion This section is for non-tech specific information pertaining to 4.6L (Modular) Mustangs built from 1996 to 2004.

Car is getting slower in 1/4

Old 06-27-2011, 07:44 AM
  #21  
teej281
4.6L Section Moderator
 
teej281's Avatar
 
Join Date: Nov 2007
Location: South Central PA
Posts: 10,286
Default

Do not run drag radials on your IRS! If anything find an extra 2 v6 wheels and throw some slicks on them if you want to run. IRS+DR's=broken half shafts every time.

Back to the issue at hand. I think its all in the 60' and the spinning after shifts thats hurting you. Spinning will add MPH but hurt ET. Its been proven many times. Also, clutch slipping is probably the reason for the slower 60'. Plus tires could have been "newer" and bit better back 2 years ago. Overall, I think your car is still performing the same, just the clutch might have seen its better days and the tires might not be as grippy as they were. Track prep too is also a concern to check into.
teej281 is offline  
Old 06-27-2011, 10:43 AM
  #22  
Moonshine
5th Gear Member
 
Moonshine's Avatar
 
Join Date: Nov 2008
Location: Wa
Posts: 2,293
Default

Teej....why is it okay to run slicks but not drag radials?
Moonshine is offline  
Old 06-27-2011, 10:48 AM
  #23  
teej281
4.6L Section Moderator
 
teej281's Avatar
 
Join Date: Nov 2007
Location: South Central PA
Posts: 10,286
Default

Radial means stiffer sidewall than a slick. Running full slicks give you the soft sidewall to absorb the shock of a launch. Drag radials stick great, but they have a radial sidewall which is still stiff and shocks the halfshafts hard on a launch, contributing to their failure.
teej281 is offline  
Old 06-27-2011, 11:00 AM
  #24  
uberstang1
Chupacabra
 
uberstang1's Avatar
 
Join Date: Jul 2004
Location: wilkes-barre PA
Posts: 9,621
Default

Slicks will kill irs halfshafts fast as well, i got 3 terminators drivers berween 470 and 520 and a tow truck driver to attest to it.
uberstang1 is offline  
Old 06-27-2011, 11:05 AM
  #25  
teej281
4.6L Section Moderator
 
teej281's Avatar
 
Join Date: Nov 2007
Location: South Central PA
Posts: 10,286
Default

Well if there is an issue with the half shaft before putting the slicks on it will break. But you'll have less chance breaking with a slick.
teej281 is offline  
Old 06-27-2011, 11:25 AM
  #26  
uberstang1
Chupacabra
 
uberstang1's Avatar
 
Join Date: Jul 2004
Location: wilkes-barre PA
Posts: 9,621
Default

Originally Posted by teej281
Well if there is an issue with the half shaft before putting the slicks on it will break. But you'll have less chance breaking with a slick.
May be less chance but it still a good chance of failure regardless especially with high hp. A 400 hp car with irs has the same axle failure rate as a 500rwhp car woth a 28 spline SRA, both woth equivent tires
uberstang1 is offline  
Old 06-27-2011, 11:32 AM
  #27  
teej281
4.6L Section Moderator
 
teej281's Avatar
 
Join Date: Nov 2007
Location: South Central PA
Posts: 10,286
Default

There are guys running 9's on stock half shafts with 700rwhp on slicks...
teej281 is offline  
Old 06-27-2011, 11:37 AM
  #28  
uberstang1
Chupacabra
 
uberstang1's Avatar
 
Join Date: Jul 2004
Location: wilkes-barre PA
Posts: 9,621
Default

Another thing that makes me further disagree about this slap a slick on and go theorybis that for car under 300 wheel HP a full blown rinkle wall slick is probably to much tire forthe power level which means your reall gonna have to come off the line hard and high in the rpm range so u dont bog it out which honestly maybe more stress than coming off the softer with a drag radial. I mean if you think ur gonna put a slick on a 260rwhp and come off the line at 2500 you got another thing coming.
uberstang1 is offline  
Old 06-27-2011, 11:39 AM
  #29  
uberstang1
Chupacabra
 
uberstang1's Avatar
 
Join Date: Jul 2004
Location: wilkes-barre PA
Posts: 9,621
Default

Originally Posted by teej281
There are guys running 9's on stock half shafts with 700rwhp on slicks...
Im sure there is, i can also read on the internet people running 9s on a horrible stock chevy 10 bolt. My 3 examples are from first hand expereince of friends cars at the track not what some guy managed to get away with on the internet, just saying. I think your JDM roots are showing a little Teej dont take offense.

Last edited by uberstang1; 06-27-2011 at 11:42 AM.
uberstang1 is offline  
Old 06-27-2011, 11:59 AM
  #30  
turbo232
4th Gear Member
 
turbo232's Avatar
 
Join Date: Mar 2010
Location: GA
Posts: 1,232
Default

Originally Posted by teej281
There are guys running 9's on stock half shafts with 700rwhp on slicks...
yeah...but if they are running autos that absorbs some of the shock as well.
turbo232 is offline  

Thread Tools
Search this Thread
Quick Reply: Car is getting slower in 1/4



All times are GMT -5. The time now is 11:40 PM.