Track wheel hop problems, advice?
#1
04-10-2006, 02:07 PM
Track wheel hop problems, advice?
I have a 99 cobra with IRS, I have the 4:10's and subframe connectors but got sever wheel hop from the launch. If I'm aggressive at all my wheels wonts stay put. Is a susp. mod for this?
#2
04-10-2006, 02:13 PM
There are a few. IRS is a total pain, and you dont want to kill your halfshafts. 99/01 IRS are pretty weak compared to their 04 counterparts.
This website is all you will need to help you start to combat wheelhop. The other thing you can do is go with a higher level of halfshafts (DSS Level 2 or 3 depending on how much power you are making).
http://www.maximummotorsports.com/irs-asp.asp
Thats the IRS Junkies part source.
This website is all you will need to help you start to combat wheelhop. The other thing you can do is go with a higher level of halfshafts (DSS Level 2 or 3 depending on how much power you are making).
http://www.maximummotorsports.com/irs-asp.asp
Thats the IRS Junkies part source.
#5
04-12-2006, 10:26 AM
the independant rear is a wheelhop nightmare almost no matter what. You have to replace all the bushings with non-deflecting types, go to a pretty high rear spring rate (650 for standard type, 550+ for coil over), and generally make your car less streetable.
If you want good drag times and low maintenance then go find someone with a 99-04 GT or better yet a Mach1 and swap with them. The "live" axle is a solid axle where you have tubes extending from the differential to just before the wheels that contain the axles and allow the differential to move with the suspension. Independant suspensions remove that tube and fix the differential to the chassis which reduces unsprung weight and can improve handling. Once you have a new solid axle, then get some weight jacker arms and drag springs, or pop for some coil overs, and a maximum motorsports PHB & TA setup. You'll be moving down the track nicely with wild grip and solid handling.
Level 5 halfshafts won't help attenuate the wheel hop, they'll keep it from fragging your halfshafts so easily and are a requirement for guys that drive their car to the track instead of trailering it if they'd like to drive home. You also stand a strong chance of damaging your diff housing which is a 700 dollar aluminum part if you let the wheelhop get too bad. If it break it replace it with a 92-94 iron case from a T-Bird supercoupe. They're LOTS stronger.
So, from the MM parts bin to get your IRS useable: Aluminum diff bushings front and back, delrin control arm bushings top and bottom, poly cradle bushings, and a rear diff support (I think billetflow makes one, if not check MT or Steeda (ick.. steeda's yucky)). Also get the stage 5 halfshafts... don't cheap out. Use as stiff a spring as you can stand and it'll help to a point. Stiffer rear springs without stiffer fronts can unbalance the handling so understand there are side effects. Also, pull the front sway bar so the front end can lift and that'll help plant the back end.
In order to launch a IRS car (I've had 2 gt's that I converted to IRS) you can try my method. No guarantees but it worked well for me on the street. (start by getting a really nice warm up on the tires is you're using DR's or slicks) hum it up to about 1800-2200rpm at the green, haze the clutch out as aggressively as you can without letting it spin the tires real hard. As soon as the car starts picking up speed you've got all the traction you're going to have for a few meters so dump the clutch slowly and at the same time start matting the go-pedal very smoothly. If you do it right the launch won't break any 60' time records but it will have you off to a smoother run than you'd otherwise have which helps times.
A live axle is easily 80lbs lighter no matter what than a IRS and that's going to equal almost a tenth in the 1/4 on weight alone. Add that you can build the 8.8 live axle nicely and really beat the hell out of it without too many worries of getting home. The IRS... one problem and you're stuck.
If you want good drag times and low maintenance then go find someone with a 99-04 GT or better yet a Mach1 and swap with them. The "live" axle is a solid axle where you have tubes extending from the differential to just before the wheels that contain the axles and allow the differential to move with the suspension. Independant suspensions remove that tube and fix the differential to the chassis which reduces unsprung weight and can improve handling. Once you have a new solid axle, then get some weight jacker arms and drag springs, or pop for some coil overs, and a maximum motorsports PHB & TA setup. You'll be moving down the track nicely with wild grip and solid handling.
Level 5 halfshafts won't help attenuate the wheel hop, they'll keep it from fragging your halfshafts so easily and are a requirement for guys that drive their car to the track instead of trailering it if they'd like to drive home. You also stand a strong chance of damaging your diff housing which is a 700 dollar aluminum part if you let the wheelhop get too bad. If it break it replace it with a 92-94 iron case from a T-Bird supercoupe. They're LOTS stronger.
So, from the MM parts bin to get your IRS useable: Aluminum diff bushings front and back, delrin control arm bushings top and bottom, poly cradle bushings, and a rear diff support (I think billetflow makes one, if not check MT or Steeda (ick.. steeda's yucky)). Also get the stage 5 halfshafts... don't cheap out. Use as stiff a spring as you can stand and it'll help to a point. Stiffer rear springs without stiffer fronts can unbalance the handling so understand there are side effects. Also, pull the front sway bar so the front end can lift and that'll help plant the back end.
In order to launch a IRS car (I've had 2 gt's that I converted to IRS) you can try my method. No guarantees but it worked well for me on the street. (start by getting a really nice warm up on the tires is you're using DR's or slicks) hum it up to about 1800-2200rpm at the green, haze the clutch out as aggressively as you can without letting it spin the tires real hard. As soon as the car starts picking up speed you've got all the traction you're going to have for a few meters so dump the clutch slowly and at the same time start matting the go-pedal very smoothly. If you do it right the launch won't break any 60' time records but it will have you off to a smoother run than you'd otherwise have which helps times.
A live axle is easily 80lbs lighter no matter what than a IRS and that's going to equal almost a tenth in the 1/4 on weight alone. Add that you can build the 8.8 live axle nicely and really beat the hell out of it without too many worries of getting home. The IRS... one problem and you're stuck.
#6
04-12-2006, 11:34 AM
Here is a technical answer. http://en.wikipedia.org/wiki/Live_axle
Even better one.....
http://www.ukcar.com/features/tech/s...n/LiveAxel.htm
Many Cobra owner complain of wheel hop at the track and contemplate changing to a Live Axle like the Mach 1 has. The Live Axle doesn't have quite the handling of the IRS, however is much stronger and can launch at higher RPM's. With a little work you can make the Live Axle out handle the stock Cobra IRS any day! The good thing about the IRS is the the handling and is probably better for everyday driving comfort.
Someone with way more knowledge than me might want to chime in cause there might be a way to make the IRS just as strong and good for launching.
Even better one.....
http://www.ukcar.com/features/tech/s...n/LiveAxel.htm
Many Cobra owner complain of wheel hop at the track and contemplate changing to a Live Axle like the Mach 1 has. The Live Axle doesn't have quite the handling of the IRS, however is much stronger and can launch at higher RPM's. With a little work you can make the Live Axle out handle the stock Cobra IRS any day! The good thing about the IRS is the the handling and is probably better for everyday driving comfort.
Someone with way more knowledge than me might want to chime in cause there might be a way to make the IRS just as strong and good for launching.
#7
04-12-2006, 12:57 PM
GT Live Axle is better because of the rear brakes. You can run some NIIIICE 15" rims and put some huge drags on the rear 
.
If you are planning on staying Naturally Aspirated, you could just get some 03/04 Cobra Halfshafts and be done with it, but if you wanted more piece of mind I would go w/ level 2's. Be prepared for a pretty hefty price though. It's going to run you about $1 (level 2's) to 1.5k (level 5's).
.If you are planning on staying Naturally Aspirated, you could just get some 03/04 Cobra Halfshafts and be done with it, but if you wanted more piece of mind I would go w/ level 2's. Be prepared for a pretty hefty price though. It's going to run you about $1 (level 2's) to 1.5k (level 5's).
#8
04-12-2006, 04:13 PM
Originally Posted by r3dn3ck
the independant rear is a wheelhop nightmare almost no matter what. You have to replace all the bushings with non-deflecting types, go to a pretty high rear spring rate (650 for standard type, 550+ for coil over), and generally make your car less streetable.
If you want good drag times and low maintenance then go find someone with a 99-04 GT or better yet a Mach1 and swap with them. The "live" axle is a solid axle where you have tubes extending from the differential to just before the wheels that contain the axles and allow the differential to move with the suspension. Independant suspensions remove that tube and fix the differential to the chassis which reduces unsprung weight and can improve handling. Once you have a new solid axle, then get some weight jacker arms and drag springs, or pop for some coil overs, and a maximum motorsports PHB & TA setup. You'll be moving down the track nicely with wild grip and solid handling.
Level 5 halfshafts won't help attenuate the wheel hop, they'll keep it from fragging your halfshafts so easily and are a requirement for guys that drive their car to the track instead of trailering it if they'd like to drive home. You also stand a strong chance of damaging your diff housing which is a 700 dollar aluminum part if you let the wheelhop get too bad. If it break it replace it with a 92-94 iron case from a T-Bird supercoupe. They're LOTS stronger.
So, from the Maximum Motorsports parts bin to get your IRS useable: Aluminum diff bushings front and back, delrin control arm bushings top and bottom, poly cradle bushings, and a rear diff support (I think billetflow makes one, if not check MT or Steeda (ick.. steeda's yucky)). Also get the stage 5 halfshafts... don't cheap out. Use as stiff a spring as you can stand and it'll help to a point. Stiffer rear springs without stiffer fronts can unbalance the handling so understand there are side effects. Also, pull the front sway bar so the front end can lift and that'll help plant the back end.
In order to launch a IRS car (I've had 2 gt's that I converted to IRS) you can try my method. No guarantees but it worked well for me on the street. (start by getting a really nice warm up on the tires is you're using DR's or slicks) hum it up to about 1800-2200rpm at the green, haze the clutch out as aggressively as you can without letting it spin the tires real hard. As soon as the car starts picking up speed you've got all the traction you're going to have for a few meters so dump the clutch slowly and at the same time start matting the go-pedal very smoothly. If you do it right the launch won't break any 60' time records but it will have you off to a smoother run than you'd otherwise have which helps times.
A live axle is easily 80lbs lighter no matter what than a IRS and that's going to equal almost a tenth in the 1/4 on weight alone. Add that you can build the 8.8 live axle nicely and really beat the hell out of it without too many worries of getting home. The IRS... one problem and you're stuck.
If you want good drag times and low maintenance then go find someone with a 99-04 GT or better yet a Mach1 and swap with them. The "live" axle is a solid axle where you have tubes extending from the differential to just before the wheels that contain the axles and allow the differential to move with the suspension. Independant suspensions remove that tube and fix the differential to the chassis which reduces unsprung weight and can improve handling. Once you have a new solid axle, then get some weight jacker arms and drag springs, or pop for some coil overs, and a maximum motorsports PHB & TA setup. You'll be moving down the track nicely with wild grip and solid handling.
Level 5 halfshafts won't help attenuate the wheel hop, they'll keep it from fragging your halfshafts so easily and are a requirement for guys that drive their car to the track instead of trailering it if they'd like to drive home. You also stand a strong chance of damaging your diff housing which is a 700 dollar aluminum part if you let the wheelhop get too bad. If it break it replace it with a 92-94 iron case from a T-Bird supercoupe. They're LOTS stronger.
So, from the Maximum Motorsports parts bin to get your IRS useable: Aluminum diff bushings front and back, delrin control arm bushings top and bottom, poly cradle bushings, and a rear diff support (I think billetflow makes one, if not check MT or Steeda (ick.. steeda's yucky)). Also get the stage 5 halfshafts... don't cheap out. Use as stiff a spring as you can stand and it'll help to a point. Stiffer rear springs without stiffer fronts can unbalance the handling so understand there are side effects. Also, pull the front sway bar so the front end can lift and that'll help plant the back end.
In order to launch a IRS car (I've had 2 gt's that I converted to IRS) you can try my method. No guarantees but it worked well for me on the street. (start by getting a really nice warm up on the tires is you're using DR's or slicks) hum it up to about 1800-2200rpm at the green, haze the clutch out as aggressively as you can without letting it spin the tires real hard. As soon as the car starts picking up speed you've got all the traction you're going to have for a few meters so dump the clutch slowly and at the same time start matting the go-pedal very smoothly. If you do it right the launch won't break any 60' time records but it will have you off to a smoother run than you'd otherwise have which helps times.
A live axle is easily 80lbs lighter no matter what than a IRS and that's going to equal almost a tenth in the 1/4 on weight alone. Add that you can build the 8.8 live axle nicely and really beat the hell out of it without too many worries of getting home. The IRS... one problem and you're stuck.
#9
04-13-2006, 07:30 AM
I have to say that there's no high performance suspension that feels as good to drive as an independant rear. I originally got my first one because my back doesn't like being jarred around but I like to drive a fast car really fast. After a while I stopped commuting so far and swapping back to a solid axle made practical sense again and I got the opportunity to put a MM TA and PHB on it for no cost so I went ahead with it.
This is where I get preachy. You can tell me to go eat a back of cacks if you want but I've been there so here's my sermon:
IRS is for road course drivers. NOT drag racing. It sucks azz for dragging but is uber wonderful for turning fast. IRS can't compete with a really well set up live axle because of design deficiencies in the Mustang IRS. It's not to say that a live axle is any better, it's just hard to design an IRS that's good at everything. Pick your sport and equip for it, or just do as good as you can with what you have and buy a lot of spare parts.
Don't drag race your IRS. It's just asking for trouble and it's really leaving so much on the table time wise. You can have a nice ride and decent handling with a solid axle without snapping expensive and hard to find parts. If you break any of the parts in the IRS you're limited to the replacements that exist since there's not a need for them to be manufactured currently. I don't figure they'll ever use most of the componentry in any other car ever again.
If you're a drag racer... get rid of the IRS. You will thank me.
Hey JJT... where'd you get the tune? Apex?
This is where I get preachy. You can tell me to go eat a back of cacks if you want but I've been there so here's my sermon:
IRS is for road course drivers. NOT drag racing. It sucks azz for dragging but is uber wonderful for turning fast. IRS can't compete with a really well set up live axle because of design deficiencies in the Mustang IRS. It's not to say that a live axle is any better, it's just hard to design an IRS that's good at everything. Pick your sport and equip for it, or just do as good as you can with what you have and buy a lot of spare parts.
Don't drag race your IRS. It's just asking for trouble and it's really leaving so much on the table time wise. You can have a nice ride and decent handling with a solid axle without snapping expensive and hard to find parts. If you break any of the parts in the IRS you're limited to the replacements that exist since there's not a need for them to be manufactured currently. I don't figure they'll ever use most of the componentry in any other car ever again.
If you're a drag racer... get rid of the IRS. You will thank me.
Hey JJT... where'd you get the tune? Apex?
#11
04-13-2006, 02:12 PM
Thanks again for the info. No, I got my tune from Nick at Newtech in Hayward. Besides Apex, he is the only one I could find that uses Diablo software in the Bay. Even though I ended up ditching the Predator and had him do a custom tune. From what I could tell Newtech does some mustangs, but mostly LS1's. When I first got there he had a BAD AZZ Vert Cobra on the dyno so that made me feel better.
I originally was going to try Apex, but when I called the guy kinda blew me off so I didn't even try again. I know Apex kinda has a bad rep, but I also know they are under new managment so I wanted to give them a try. I also got the sense their volume was so high they wouldn't spend quality time trying to get it right, and that's not what I wanted. Oh well, maybe next time Apex will get my hard earned cash! ha ha
I originally was going to try Apex, but when I called the guy kinda blew me off so I didn't even try again. I know Apex kinda has a bad rep, but I also know they are under new managment so I wanted to give them a try. I also got the sense their volume was so high they wouldn't spend quality time trying to get it right, and that's not what I wanted. Oh well, maybe next time Apex will get my hard earned cash! ha ha
#12
04-14-2006, 04:12 PM
Originally Posted by HTSTANG99
If I was looking into changing my rear end set up, were am I going to find it that wont completely kill my wallet?
Or, find a used 8.8 live axle from any 99-04 or (less desireable usually) 994-98 mustang on the interweb somewhere and slowly build it up with the MM kit and a nice aftermarket diff and axle set. You'll thank yourself for using high quality parts later.
Take my word for it, I've made the mistakes, I've cheaped out and I've regretted it. Use good stuff, spend the money and enjoy your car instead of repairing it.
#13
04-14-2006, 04:14 PM
Originally Posted by jjtgiants
Thanks again for the info. No, I got my tune from Nick at Newtech in Hayward. Besides Apex, he is the only one I could find that uses Diablo software in the Bay. Even though I ended up ditching the Predator and had him do a custom tune. From what I could tell Newtech does some mustangs, but mostly LS1's. When I first got there he had a BAD AZZ Vert Cobra on the dyno so that made me feel better.
I originally was going to try Apex, but when I called the guy kinda blew me off so I didn't even try again. I know Apex kinda has a bad rep, but I also know they are under new managment so I wanted to give them a try. I also got the sense their volume was so high they wouldn't spend quality time trying to get it right, and that's not what I wanted. Oh well, maybe next time Apex will get my hard earned cash! ha ha
I originally was going to try Apex, but when I called the guy kinda blew me off so I didn't even try again. I know Apex kinda has a bad rep, but I also know they are under new managment so I wanted to give them a try. I also got the sense their volume was so high they wouldn't spend quality time trying to get it right, and that's not what I wanted. Oh well, maybe next time Apex will get my hard earned cash! ha ha
Tell em' r3dn3ck sent you.
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