Wheel Hop [Archive] - SVTOA Forums

KWladyka

11-07-2002, 12:49 AM

Has anyone had wheel hop problems with their 03 Cobra? At first the car had none but after some horsepower increases wheel hop has become extreme. Now if the tires break loose under acceleration the tires will always bounce around. With my current modifications any moderate to heavy acceleration in first or second gear will usually break traction and bring car rattling wheel hop. My understanding is the main cause is from the differential changing angles during acceleration but it looks to me that it is secured fairly well both in the front and back of the unit. Although I assume the bushings must give enough to cause the problem. I'm sure if it is doing it on my car others must have experienced the same problem. Now how to fix it is what I want to know. I talked to the folks at Kenny Brown but they only said that some owners reported having it and others did not. However, they had no solutions other than going to a live axle. I hope there is another way.

Beabout

11-07-2002, 08:56 AM

YEP me too :)

I believe that the wheel-hop problem is inherent to the IRS. I have stopped any further operation that may lead to wheel-hop. You may want to consider doing so as well. Although, SVT proclaims that they have had 1600+ launches without and axel failure it is clear that each occurance puts a great strain on the rest of the vehicle.

As to what can be done to correct the problem, just wait and some person smarter than us will come up with a simple add on or change that will correct the problem.

2003 Cobra is a great car. Perhaps even a classic.

Dana

11-09-2002, 06:26 AM

A couple of suggestions:
Get bigger, stickier tires. Less spin=less hop.
Polyurethane bushings are available. Replace them in the rear.
Launch the car at a different RPM.
These things will help reduce wheel hop. Only perfecting the launch method can eliminate it completely.
Things to try because they are cheaper than axle shafts.

Dana

white venom

11-09-2002, 07:05 AM

dont take this the wrong way but is the traction control on by any chance? i have a 99 cobra and i only spun tire 2 or 3 times but the first time i thought i had major wheel hop. it turns out i had the traction control on and what was happening was the computer sensed wheel spin and started applying the brakes on and off very rapidly. make sure your tractoin control is off next time. and if it is allready off, disregard this reply.

KWladyka

11-09-2002, 10:41 AM

Some more clarification: I do appreciate any query on what may lead to a remedy but this has nothing to do with having the traction control on. I'll also add that the traction control is basically worthless in this car especially once more horsepower/ torque is added. With it on I cannot even go to ¾ throttle in a lower gear without it activating and causing the car to completely bog down. It’s down right dangerous to use I my opinion. Anyway, not wanting to get off the subject, I can definitely say that Dana is correct: bigger, stickier tires can be a big help.

However, it was not a completely successful solution for me. I tried a pair of BFG drag radials, the same size as stock although they were actually ½ inch wider. After I first put them on I could heat them up with no wheel hop and they gave much better traction. Using them felt great on the rear end, much smoother. Nevertheless, after a few runs at the local drag strip, these tires would wheel hop just as bad on hard starts. I’m sure it had to do with the condition of the track, that is, all the rubber that was being left on the pavement by other cars but it prevented me from getting a good start off the line. Yes, one can adjust the way they start to avoid the hop but I would really like to be able to start hard without the problem. Moreover, after one night at the strip, these tires were almost completely worn down to the tread lines. So they would not be useful for day-to-day driving. I want to use tires that I won’t need to change all the time. Slicks may help to prevent the problem but again, I want to fix this issue so I won’t have the problem with street tires.

Additionally, while it may be true that wheel-hop problem is inherent to the Ford IRS, I do not want to stop any further operation that may lead to wheel-hop. I just want to fix the problem. At least for me the whole idea of having this car is being able to drive it hard from time-to-time and I don’t want to settle for anything less. I know there are other high performance cars that have IRS and don’t seem to have the problem. So I’m going to believe that it can be remedied. I think the stiffer bushing suggestion is a good one. Does anyone have a link for stiffer bushings for this car? The people at Kenny Brown were not helpful.

Thanks much for the feedback!

Dana

11-09-2002, 10:56 AM

Try Steeda maybe or JDM for the bushings. They're out there, just haven't looked real hard for them yet.
Dana

2k3cobra

11-09-2002, 06:49 PM

I too have experienced this hideous wheel hop. Like you, it has happens easier now at 3500 miles than when I first purchased the car. This is with traction control (sucks/dangerous) off. In addition, this is will happen with moderate RPM launches.

I love this car, but I wouldn't bet that 60' times could beat a stock civic at times.

:(

dennish

11-10-2002, 05:00 PM

I'm sick and tired of it too. Vett's don't wheel hop. Even with blowers...anyone know why???:bash: To the engineers that designed this IRS.

cobrajim9999

11-10-2002, 09:18 PM

Vettes do have wheel hop but because tranaxle is bolted to rearend it has a heavier amount of weight planting tires but they also get wheel hop.

dwtalso

11-10-2002, 10:29 PM

Originally posted by dennish
I'm sick and tired of it too. Vett's don't wheel hop. Even with blowers...anyone know why???:bash: To the engineers that designed this IRS.

'Vettes have plenty of hop. Supra's too. And BMW's. Hop is inherent in the IRS and a function of traction and unsprung weight. In the right place at the right time every IRS will hop. With a properly tuned setup and traction it might be more of a skip but it's still there. I have a great video of a well tuned, high power Supra skipping through three gears :).

Put on tunable shocks, stiffer springs, lighter wheels, and upgrade all the bushings. Run a high traction tire and find a shock setting that minimizes the hop conditions for your setup. This will be as good as it gets.

JT COBRA

11-11-2002, 11:25 AM

I also experienced wheel hop with stock radials

first I purchaced some Nitto 555r 315/35/17

worked very well until mods then started wheel hop again

next purchased QA1 adjustable rear shocks and began

playing with settings ( at 4 clicks works for me) and then

changed bushings and cut rear coils one full coil ( sits perfectly

level now) . You'll never believe how stiff the stock rear shocks

are.

best 60ft on radials this weekend 1.71 at south carolina

dragway ( north of jackson, SC) .

car went 11:70 @ 118.87 lots cobras there with SCMC

from alanta area believe there was some from the SVTOA

alanta chapter too. A good turn out and great weather

HAD A BLAST !!!!!!!!!!!!!!!!!!! a small drive 851 miles one way

JT COBRA

11-11-2002, 11:34 AM

KWladyka

11-11-2002, 06:33 PM

JT COBRA that's helpful information. Thanks. Where did you purchase the shocks and bushings? What type of bushings did you get? I was also wondering how long it took to make these changes. Are you saying that cutting the coil springs helped or was that just a cosmetic change?

Dana

11-11-2002, 07:11 PM

I e-mailed Kenny Brown with this message:

Do you have a simple kit that would contain all the necessary pieces to replace the stock bushings in an '03 Cobra rear suspension with your poly bushings? I'm trying to head off any wheel hop problems.

and got this response:

Dan the part Number is kbp-87001 and retails for 49.50.

Thank you for your interest in Kenny Brown Performance Products,

Rich Cottrell
Kenny Brown Performance
317.247.5320 x 219
rcottrell@kennybrown.com

I have not checked any further into this yet, but I will soon. It's a place to start.

Dana

KWladyka

11-11-2002, 07:57 PM

Yes that was the same guy I talked to. He also pointed out that part but said he didn't know if would help the problem. He said they had not really figured out how to fix this issue yet (other than using a live axle). My understanding was that this was also only one bushing so I also asked him for a picture because there are several pieces of equipment that connect to the differential and I wanted to see what he was referring to. I have not received a reply although I have sent several email queries.
I just got the impression that he didn't really know what to do.

Dana

11-11-2002, 08:08 PM

I guess I'll have to find out just what this kit contains...

Dana

GChronis

11-19-2002, 04:36 PM

http://www.superstallions.com/forum/viewtopic.php?t=1229

And a review:
http://www.superstallions.com/forum/viewtopic.php?t=1857

KWladyka

11-19-2002, 11:13 PM

Thanks George,

That fix looks good and although I have a coupe, I'm thinking I'll need stage II.

JT COBRA

11-20-2002, 07:14 AM

nothing special have to see it in action!!!!!!

same thing I did alot less money .

QA1 shocks work great 12 adjustments ( 279 pr )

cut stock set of springs one coil

lowers rear about 1.25" ( new $80.00 pair at ford)

conv 470# coupe 600#

kenny brown bushing kit (50-100 set)

lowering rear moves transfer center towards

rear of car ( get weight on tires quicker )

when they go 1.7 60fts on nittos 555r

I will believe!!!!!!!!!!!!!!!!!!!

still think that new coil over shock setup for IRS

is going to be the best

It moves the control on the lower arm out and back further

should show improvement

Thanks

JEFF

:D :wtf: :D

KWladyka

11-20-2002, 09:30 AM

Good point Jeff and if their Stage one is really just shocks that's a steep price.

GChronis

11-20-2002, 10:29 AM

This is what Amazon's defense was:

eibach springs were NOT designed to control the wheelhop problem, they were made to lower the vehicle and they have a firmer ride, our springs WERE designed to control the wheelhop issue, lower the car for a better appearance and last but not least, PRESERVE the great ride quality that the IRS suspension was designed for. I have the stage 1 and 2 kits on my vert, and i can tell you this without a doubt, the hop problem is just about totally eliminated, even in the cold weather with cold tires, which is the worst possible conditions to control the wheel-hop. My car used to hop at very light throttle in 1st and 2nd gears, it made the car terrible to drive, and is super bad for the halfshafts, now , even in the cold it takes a combo of uneven road I.E. bumpy, rough and FULL throttle to even make it hop a little. With the addition of the stiff bushings for the centersection i am confident the problem is well under control now. We have done extensive testing with shock valving and after months of testing and much money we finally have a product that can be adjusted to combat the wheel hop, AND when a stock type ride is desired a simple turn of the adjustment knob and it's if the car has never been modified in the suspension dept! Rick and i have done all the hard work, testing dozens of setups so you guys WON'T have to. Give this stuff a try, you won't be dissapointed. Working with the design ford has given us, we feel the results are well worth the money. One last bit of info we found during our months of testing, on these cars with both of the kits installed, even when fully modded, making over 450 at the tire, the stock tired cars in the cold didn't hop at all, the bfg drag radial cars didn't hop at all , the only cars that even hopped a little were the cars on the nitto tires, but even they only hopped when the tires had no heat in them, when you first started driving like in the morning after it sat all nite. We hope this post will help you get a better idea what we went through to help our fellow stangers out with a very real problem when you have a high horsepower irs cobra, it has been tested on 1999, 2001 and 03 cobra with great results, thanks for you time, hermann of horsepower by hermann www.hbh.org, and rick of amazon racing www.amazonracing.com icon_smile.gif

Not saying they're right, just repeating what they said.

JTFX6552

12-04-2002, 08:28 AM

Originally posted by JT COBRA
nothing special have to see it in action!!!!!!

same thing I did alot less money .

QA1 shocks work great 12 adjustments ( 279 pr )

cut stock set of springs one coil

lowers rear about 1.25" ( new $80.00 pair at ford)

conv 470# coupe 600#

kenny brown bushing kit (50-100 set)

lowering rear moves transfer center towards

rear of car ( get weight on tires quicker )

when they go 1.7 60fts on nittos 555r

I will believe!!!!!!!!!!!!!!!!!!!

still think that new coil over shock setup for IRS

is going to be the best

It moves the control on the lower arm out and back further

should show improvement

Thanks

JEFF

:D :wtf: :D

I go 1.7x 60 fts all the time with the stock set up on DR's, but I don't think that means that this kit is no good. If I was having hop trouble, I'd give it a try.

Rick and Herman took a convertable that was having big time wheel hop problems and did a lot of experimenting to come up with good shock valving to eliminate the hop. The shocks are custom made, hence there high cost at the moment. The kit has been tried by others with great success. As it has been explained to me, the 'verts are more prone to hop because of the different rear spring rate.

NJC

12-04-2002, 09:13 AM

I have the same problem with my car. Went to the drag strip and everytime I would heat the tires up it would wheel hop. I ended up that night snaping the left rear axel. I have since then put on a Kenny brown Irs Carrier. I have not been to the strip yet. I am affraid Im going to snap it again. 460RWHP. I now feel a viberation when I slow down from about 30 to 15 but only when I slow down with it in gear(down shifting). But I would recomend kenny brown I put just aboud all the frame kits, the caster kit shock towne brace and alot more. the car fells much stiffer. That unie body cant take much stress for long with out something braceing it up.

SRiley

12-04-2002, 03:20 PM

has anyone tried the Amazon kit to see if it works like they say it does?

JT COBRA

12-05-2002, 07:09 AM

Funny I was at the Bowling Green shootout did not see one in the

1.7 area HUH???? did I miss something?????

I dont see any wheel hop with my mods. It either leaves or spins

usually dependent on track conditions!!!!!!!!

I did not say their kit does not work but alot of us buoght these

cars on an average budget not millioniares pocket just trying to

help those who cant afford and want improvement!!!!!!

not here bashing their kit just showing there are more than one

way to modify cars?????

BY the way I have been inthe 1.6's on nittos but not consistently

i dont post by best it usually my most consistent if its any test

my girlfriend run 1.7s with the car but only at 12:15@117

what ever works for stick with it !!!!!!!!!!!!!!!!!!!

if someone other than the designers ( he who paid) please

let us how it work (I always want something better)

THanks

JEFF

P.S. JT if I remember right you had the blue one with NOS finished

right behind MATT with NOS ?????

JTFX6552

12-05-2002, 07:50 AM

Originally posted by JT COBRA
Funny I was at the Bowling Green shootout did not see one in the

1.7 area HUH???? did I miss something?????

I dont see any wheel hop with my mods. It either leaves or spins

usually dependent on track conditions!!!!!!!!

I did not say their kit does not work but alot of us buoght these

cars on an average budget not millioniares pocket just trying to

help those who cant afford and want improvement!!!!!!

not here bashing their kit just showing there are more than one

way to modify cars?????

BY the way I have been inthe 1.6's on nittos but not consistently

i dont post by best it usually my most consistent if its any test

my girlfriend run 1.7s with the car but only at 12:15@117

what ever works for stick with it !!!!!!!!!!!!!!!!!!!

if someone other than the designers ( he who paid) please

let us how it work (I always want something better)

THanks

JEFF

P.S. JT if I remember right you had the blue one with NOS finished

right behind MATT with NOS ?????

First, no NOS on my car. At BG, I had 4 mods total, L pulley, Amazon Diablosport Chip, Amazon Cold Air kit, Borla cat back.

Second at BG I was running on the stock F1's. My best 60 ft on F1's there 1.839, ET 11.790.

I added the DR's later, I only haven't had a 1.7x 60 ft three times. All the rest 1.7x, with the entire suspension completely stock. I just went on a "street" night to Atco, where the temperature was 30 degrees. According to everyone, bad traction. '03 + Dr's... 1.718 60 ft.

If your opinion is your homemade kit helped your wheel hop, great, I'm happy for you. But I don't think you getting 1.7x or the occasional 1.6x 60 fts means anything.

Wow, your GF drives GOOD!

JT COBRA

12-05-2002, 09:29 AM

SUPPOSE NEXT YOUR GOING TO TELL ME

YOU HAVE THE SWAY BAR STILL ON TOO

WHAT EXACTLY IS STOCK???????????

YOUR POSTED MILE PER HOUR IS A LITTLE HIGH

FOR NO NOS ( GOOD CHIP ?)

AND GETTING 11:40'S ON DRAGS

YOUR TELLING US ALL WE DONT NEED ANY SUSPENSION

UPGRADES THEN ???????????????????

AND CAN ANY ONE GET THESE NUMBERS IN YOUR CAR??????

OR OUR CARS??????

SEEMS GREAT WHAT DO WE NEED TO DO????????

SO YOU STILL HAVE WHEEL HOP PROBLEMS??????

OR YOU HAVE THIS SUSPENSION AND GETTING 1.6 OR 5'S NOW

I GUESS i AM LOST HERE????????

AND I TOO MIGHT GET 1.7' ON F1 BUT THEY SUCK IN THE

CORNERS DID NOT LIKE THEM !!!!!!!!!!!!!!!!!!!!!!!!!!!

WHERE IS THE THE IMPROVEMENT???????

1.7'S ON STOCK SUSPENSION AND STOCK TIRES ( WITH NO VHT)

IS IMPRESSIVE SO THIS NEW SUSPENSION ONLY HELPS WHEEL

HOP???????

HELP ME HERE??????

SEEMS SO EXPENSIVE OF A WHEEL HOP FIX THEN

side note : letting up on the throttle helps wheel hop and

smoother release of the clutch these cars make

lot of torque.

LOVE THIS FORUM

THANKS

JEFF

JTFX6552

12-05-2002, 10:18 AM

JT Cobra, Why are you yelling?

My MPH is what it is, no NOS ever even near my car.

My chip is one of Rick's (Amazon Racing) most conservative tunes.

My best MPH with just the 4 mods on the factory F1 tires was 121.39, 11.751 with a 1.874 60 ft at Atco the week before Bowling Green. That was full weight, with the sway bar on and the spare and jack in the trunk. As I am sure you remember, it was pretty hot for September the day of the '03 shootout, where I ran the 11.790@121.39. At BG I took out the spare and jack and removed the front sway bar, since everyone else was doing it and it was the '03 shootout afterall. Anyway, whatever the "no sway bar mod" is worth, it ain't much.

I put that stuff back after BG.

I added two other mods, too, but they didn't improve anything on the dyno or at the track, at least not in the cool air (see thumbnail in my signature), best on F1's with the new mods 11.709 @ 121.86.

I added the Dr's and then it went the 11.410@ 122.98, on that run the 60 ft was only ok, a 1.780.

I do not have, and never did have any wheel hop problems. Only on the worst prep track did I ever hop at all, (englishtown, first run on a friday night).

The suspension is untouched. I can only speak as to what I can do in my car, since no one else has driven it. I don't know about other cars either. But mine ran what I said it did, and it will go faster.

JT

JT COBRA

12-05-2002, 01:03 PM

did not mean to yell !!!!!!!

good mph then every track places their radar

different a couple tracks upto 60 ft after lines

it was hot and i could not shift bad quadrant

12.01 @ 113.xx missed fourth could have been

11 something I 've seen amazon chips seem to

make mph ( =HP) matt I believe has one too

he seems to go well into 120's

Ive been 120.87 local track

wonder what their changing different ???????

ALWAYS WANTING MORE

JEFF
:bna :( :bna

rickb

02-05-2003, 02:19 PM

I HAVE A 2003 COBRA RAG TOP AND HAVE 9600 MILES ON IT,
NO MODS, WHEEL HOP IS BAD, TAKE OFF OR ROLLING.

I AM LOOKING TO SOLVE PROBLEM, NOT LOOKING TO RACE ON TRACK, I BOUGHT FOR ENJOYMENT AND EATING VETS UP

KWladyka

02-15-2003, 11:16 PM

I finally got around to replacing the stock bushings with polyurethane bushings. Once I removed the stock bushings I could see that they were pretty beat up and the rubber section that goes into the differential (between the outer bushings) was deformed. The stock bushings had stress lines all over them.

Once the new bushings were in, for the first time in about 5 months I could smoke the tires with NO wheel hop. Since adding horsepower it was nice to see the power turn the tires like they were on butter rather than bounce them all around. Now I just need some sticky tires.

I have to assume those who don't have hop must still have bushings that are in good shape.

To change the bushings, I had to remove the exhaust and cross-brace and that cross-brace is bolted on real tight (as it should be). Also make sure you get the right kit. The stock bushings are slightly angled to fit inside a small lip on the sides of the differential. So if your kit comes with bushings with 90 degree edges its probably not the right one.

davideast

02-16-2003, 12:38 PM

KWladyka,

Which bushings are you referring to? The ones that attach the front of the differential to the cross brace I assume. Not the ones that are used in the control arms? Where did you get your bushings? How much and what part No.? Do you have any other suspension mods that may influence your results from a stock set-up? What about tires? Miles on tires if stock? Coupe or vert? Smaller pulley or stock?

Sorry for all the questions, but I've noticed that results vary and the less variables the better for accurate comparisons.

I have a bad hop problem, but it got a bit better when the dealer swapped out the differential, driveline and tires to fix the Vibration issue. I figured the new tires were a big part of it.

I bought the steeda bushings but haven't installed them yet.

Later
Dave

PS I grew up in Post Falls Idaho

KWladyka

02-16-2003, 02:06 PM

Hi Dave

Yes specifics are good. Here is what I know. The bushings are the two on the front of the differential near where it bolts to the drive shaft. I purchased the bushings from Steeda and they were $39.95. The part number was 324-IRS-100 but as I mentioned in my post I would recommend a bushing kit with a slightly tapered side like the stock bushings. This is necessary because of a small lip you will find on the sides of the differential. This kit does not have tapered bushings and I had to cut a small groove in each so they would fit over/against the lip. Moreover, the inner bushings (about the size of 4 quarters which slide over the inner steel sleeve) were slightly too large and I had to shim those as well to get it to fit into holes with the steel sleeves inserted. Finally, the instructions are wrong. They are not accurate for a 2003 install.

Steeda has this advertised as “1999 & 2002 Cobra Differential Bushings” and I asked them if this kit would also fit a 2003. The salesman assured me it would but I disagree. It will only fit if it is tweaked. I would have returned it but it took me several hours to get to the point of replacing the stock bushings and they definitely needed to go. It was one of those things in life were one just yells out S***! and makes it work the best they can. So be mindful of these problems.

Nevertheless, after the install I was very happy. No hop, all the power to the tires which now spin like they are greased. That I can fix with sticky tires but at least there is no more hop!

My feeling on this hop problem is that a spring remedy and/or shocks can help by transferring weight to the tire to reduce or maybe even prevent a wheel that is trying to hop but it is differential moving that starts the process in the first place. Eliminate it there and no other remedy may be necessary. I think that is why no one has this problem just after buying the car but only after horsepower mods or time weaken the differential bushings. I’m sure that anyone who has a hop problem will find their differential bushings in the same state that I found mine: mangled.

I do not have any suspension modifications. Everything (but these bushings) is the factory setup. The car is a coupe with stock F1 tires with a 2.8 pulley. The tires have almost 6000 miles and are in good shape

Hope this helps.

P.S. The weather here in Southern Idaho has been good. I drive this car almost everyday.