+1 on the wheel bearings and alignment
The IRS Tech Article
- Thread starter Snake Eyes
- Start date
As of right no. Kenny Brown did but I do not recomend them due to part failures and quality control issues.
DC97Cobra said:
Been a while since I have bene here but just wanted to give you all an update. The culprit turned out to be the tires. The previous owner had Michelin 255/45/17s on a 17x8 rim. I purchased some Continental tires and the problem went away!
I'm guessing that the tire's sidewalls were bad due to the tire bowing out. Everyone kept telling me that 255 size tires are fine on a 8" rim. This proved to me that it isn't.
I have gone through and completely rewritten the entire article. Let me know what you think.
Looks good to me Kyle!! :-D I'm pretty sure you and I are on the same page! :read:
Which translates to making the Red and Blue Pill pretty much obsolete!
FWIW
:thumbsup::coolman::beer:
Nice job!:beer:
Awesome article, I, myself have been looking to buy a 2001 Cobra for awhile now and after
i get 1, would really like to make the suspension even better but i didnt know where to
start and had little to no knowledge of the IRS system on the cobra or the problems
they faced and Now i have a list.... as soon as i find one i like.
Thanx much
i get 1, would really like to make the suspension even better but i didnt know where to
start and had little to no knowledge of the IRS system on the cobra or the problems
they faced and Now i have a list.... as soon as i find one i like.
Thanx much
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This thread is BAD ASS. Definatly bookmarked. One day the wife will get sick of driving her 01', (I hope) so I can turn it into a pissed off corner carver.
so ill just want to clarify that in a sense, Bump Steer is characterized by the changing toe angle and chamber angle as the wheel moves up and down with the suspension.
And just so its known the link to the sketch of the IRS in the II.Intoduction didnt work for me
And just so its known the link to the sketch of the IRS in the II.Intoduction didnt work for me
Bumpsteer is strictly the toe change as the suspension travels up and down. Below is a nice video explaining bumpsteer and demonstrating it's setup.
http://fulltiltboogieracing.com/Videos/bumpsteer explained.wmv
More informative videos are available at:
Informational Videos
http://fulltiltboogieracing.com/Videos/bumpsteer explained.wmv
More informative videos are available at:
Informational Videos
Thanx, id had seen that video but none of the other 1s that are good too.
I had read on a different website that it also changes chamber as it travels but guess they were wrong,
Thanx much
Camber does change but bumpsteer only refers to the toe change. Camber change is refered to as the camber curve.
Late Model Mustang Suspension Basics
Late Model Mustang Suspension Basics
Thanks for answering my questions, thats a great website
Digging this up again! Just wanted to see if it was possible if you had any specific directions for IRS/SRA swaps? Im putting an 04 IRS into my 04 Mach 1 which currently has the SRA. Any info would be helpful, and yes ive reseached and found other threads about it, but was just wondering if you had any insight on the swaps. Also Installing of (Steeda) Bump Steer kits. Thanks, great right up!
This is about as good as it gets as far as a write up for the swap (though it is written to swap in a SRA it basicly tells you everything you need to know).
http://www.svtperformance.com/forum...obra-irs-8-8-live-axle-swap-details-pics.html
cobraracer46
Banned
MM tech support comparing the MM IRS kit to the FTBR kit:
The comparison listed above from the FTBR website contains quite bit of incorrect information about MM products.
The actual price for the MM IRS upper and lower Delrin control arm bushings is $498.68. This includes the tools to install the bushings which are an essential requirement to get the job done.
IRS Rear Grip Package - The Basics [MMRG-20] : Maximum Motorsports, the Latemodel Mustang Performance Suspension Leader!
The price for the FTBR IRS upper and lower Delrin control arm bushings is $410. This does not include the price of the required tools to install the bushings. This costs an additional $70. This brings the total cost to $480. A 3.9% difference, $18.68.
The comparison of the differential mounts is invalid. The quoted kit from MM (MMIRSB-40) is not a bushing replacement, but a complete mount replacement made of aluminum. This is a very high strength design that will not break at any power level. The gear cover housing will break first. All of the components in the kit are aluminum and will therefore conduct more gear noise into the IRS subframe.
IRS differential mounts, aluminum, pinion angle adjustable [MMIRSB-40.1] : Maximum Motorsports, the Latemodel Mustang Performance Suspension Leader!
The more suitable kit to compare the FTBR differential bushing kit to would be the MMIRSB-45 ($50.58). This is a polyurethane bushing replacement kit with installations tools. It is $104.42 cheaper than the FTBR equivalent.
IRS differential mounts, urethane, complete kit [MMIRSB-45] : Maximum Motorsports, the Latemodel Mustang Performance Suspension Leader!
With regards to the MMIRSTR-1 tie rod kit. This kit does not include higher strength inner tie rod tubes as most customer do not need these. The higher strength inner tie rod tubes are primarily needed by drag racers and cars involved in wheel to wheel racing. Slight wheel to wheel contact will bend the OEM inner tie rods. For most customers using their car for street use, they aren't needed. The customer is better off spending that money somewhere else on the car. That is why we sell two different tie rod replacement kits.
On the subject of the inner tie rod tubes themselves, we use aluminum for a good reason. The IRS uprights are no longer serviced by Ford. In an accident or collision, you need something in the system to be a fuse so the steering arm or inner subframe mounts are not damaged. That is the job of the inner tie rod tube.
On the subject of the studs and spacers included in the tie rod kit itself. We have designed and manufactured custom parts for both of these applications. The studs are made of the correct steel alloy, with proper hardening, stress relieving and thread rolling. They are expensive to manufacture. The spacers are made of high strength steel alloy to allow the nuts to be torqued to a high enough level to give the stud the proper amount of stretch. Without the proper amount of stretch in the stud, the nuts can come loose when the stud is subjected to radial loads from cornering. Once the nut comes loose, the steering arm can fail very quickly or the outer tie rod can fall off. These are parts where cutting any corners in the design or manufacturing is unacceptable as they allow the driver to control or not control the direction of the vehicle.
We've tested plenty of competitors bumpsteer studs and spacers that just mushroomed when torqued to the proper amount of stretch.
On the subject of the IRS subframe to chassis mounting bolts. Why would you want to install the wrong bolts in the car, even if they were a total of $5.97 cheaper? Ford has almost completely purged the car of English fasteners, so you can work on the car with one set of tools. I don't want to use two sets of tools. For a total cost difference of $5.97 you get real OEM Ford bolts and nuts from MM with the proper flanged heads, shank diameter and much better corrosion resistance than a generic zinc plated grade 8 bolt.
On the subject of the polyurethane subframe bushings. We use the appropriate bushing material for the appropriate application. In the case of the upper control arms as an example, you must use a very stiff material as the bushings are very close to each other. The moment (torque) applied to the bushing pair has a lot of leverage on them, so they must be made of a stiff material to resist deflection.
On the other hand, the subframe bushings are very far apart, so much less bushing stiffness is needed to keep deflection to a designed level. The custom polyurethane we use is several times stiffer than the OEM rubber bushings. This limits deflection to an acceptable level.
What about using an incompressible (very stiff) bushing material in the IRS subframe mounting locations? There are at least two major problems with this.
1) NVH. The subframe bushings are the last series element between the road and the body of the car. The amount of NVH that they transmit to the body is a function of their stiffness. If you make them out of aluminum, Delrin, etc they are going to conduct much more NVH into the body. The correct durometer polyurethane in this case gives acceptablely low NVH and low deflection for good handling. There is no free lunch here.
2) Installation. The IRS subframe is a large weldment. The exact location of the four mounting tubes is not that well controlled. Installing the first two bushings and getting the bolts to go through the holes in the chassis is not that difficult. To get the second pair of bolts into the chassis holes can be a challenge. When you have an incompressible bushing in the subframe, this job can very very difficult. You may need to use a ratchet strap to bent the subframe into position. This is not fun when you are trying to hold up 150lbs+ of IRS stuff. If the subframe bushings allow some deflection, this job becomes much easier. This is why Ford installed M12 bolts at one end of the subframe from the factory. It added enough slop to make the installation easier.
The $332 cost savings quoted is pure fiction. It is made not using the actual MM component prices. It is made comparing oranges to apples in terms of products. When one accurately compares the prices of the various IRS kits, in some cases the MM prices are lower, in some the FTBR prices are lower, but this is primarily a function of how the products are grouped. In most cases it is not possible to do an apples to apples comparison.
____________________________________
Jack Hidley
Maximum Motorsports Tech Support
The comparison listed above from the FTBR website contains quite bit of incorrect information about MM products.
The actual price for the MM IRS upper and lower Delrin control arm bushings is $498.68. This includes the tools to install the bushings which are an essential requirement to get the job done.
IRS Rear Grip Package - The Basics [MMRG-20] : Maximum Motorsports, the Latemodel Mustang Performance Suspension Leader!
The price for the FTBR IRS upper and lower Delrin control arm bushings is $410. This does not include the price of the required tools to install the bushings. This costs an additional $70. This brings the total cost to $480. A 3.9% difference, $18.68.
The comparison of the differential mounts is invalid. The quoted kit from MM (MMIRSB-40) is not a bushing replacement, but a complete mount replacement made of aluminum. This is a very high strength design that will not break at any power level. The gear cover housing will break first. All of the components in the kit are aluminum and will therefore conduct more gear noise into the IRS subframe.
IRS differential mounts, aluminum, pinion angle adjustable [MMIRSB-40.1] : Maximum Motorsports, the Latemodel Mustang Performance Suspension Leader!
The more suitable kit to compare the FTBR differential bushing kit to would be the MMIRSB-45 ($50.58). This is a polyurethane bushing replacement kit with installations tools. It is $104.42 cheaper than the FTBR equivalent.
IRS differential mounts, urethane, complete kit [MMIRSB-45] : Maximum Motorsports, the Latemodel Mustang Performance Suspension Leader!
With regards to the MMIRSTR-1 tie rod kit. This kit does not include higher strength inner tie rod tubes as most customer do not need these. The higher strength inner tie rod tubes are primarily needed by drag racers and cars involved in wheel to wheel racing. Slight wheel to wheel contact will bend the OEM inner tie rods. For most customers using their car for street use, they aren't needed. The customer is better off spending that money somewhere else on the car. That is why we sell two different tie rod replacement kits.
On the subject of the inner tie rod tubes themselves, we use aluminum for a good reason. The IRS uprights are no longer serviced by Ford. In an accident or collision, you need something in the system to be a fuse so the steering arm or inner subframe mounts are not damaged. That is the job of the inner tie rod tube.
On the subject of the studs and spacers included in the tie rod kit itself. We have designed and manufactured custom parts for both of these applications. The studs are made of the correct steel alloy, with proper hardening, stress relieving and thread rolling. They are expensive to manufacture. The spacers are made of high strength steel alloy to allow the nuts to be torqued to a high enough level to give the stud the proper amount of stretch. Without the proper amount of stretch in the stud, the nuts can come loose when the stud is subjected to radial loads from cornering. Once the nut comes loose, the steering arm can fail very quickly or the outer tie rod can fall off. These are parts where cutting any corners in the design or manufacturing is unacceptable as they allow the driver to control or not control the direction of the vehicle.
We've tested plenty of competitors bumpsteer studs and spacers that just mushroomed when torqued to the proper amount of stretch.
On the subject of the IRS subframe to chassis mounting bolts. Why would you want to install the wrong bolts in the car, even if they were a total of $5.97 cheaper? Ford has almost completely purged the car of English fasteners, so you can work on the car with one set of tools. I don't want to use two sets of tools. For a total cost difference of $5.97 you get real OEM Ford bolts and nuts from MM with the proper flanged heads, shank diameter and much better corrosion resistance than a generic zinc plated grade 8 bolt.
On the subject of the polyurethane subframe bushings. We use the appropriate bushing material for the appropriate application. In the case of the upper control arms as an example, you must use a very stiff material as the bushings are very close to each other. The moment (torque) applied to the bushing pair has a lot of leverage on them, so they must be made of a stiff material to resist deflection.
On the other hand, the subframe bushings are very far apart, so much less bushing stiffness is needed to keep deflection to a designed level. The custom polyurethane we use is several times stiffer than the OEM rubber bushings. This limits deflection to an acceptable level.
What about using an incompressible (very stiff) bushing material in the IRS subframe mounting locations? There are at least two major problems with this.
1) NVH. The subframe bushings are the last series element between the road and the body of the car. The amount of NVH that they transmit to the body is a function of their stiffness. If you make them out of aluminum, Delrin, etc they are going to conduct much more NVH into the body. The correct durometer polyurethane in this case gives acceptablely low NVH and low deflection for good handling. There is no free lunch here.
2) Installation. The IRS subframe is a large weldment. The exact location of the four mounting tubes is not that well controlled. Installing the first two bushings and getting the bolts to go through the holes in the chassis is not that difficult. To get the second pair of bolts into the chassis holes can be a challenge. When you have an incompressible bushing in the subframe, this job can very very difficult. You may need to use a ratchet strap to bent the subframe into position. This is not fun when you are trying to hold up 150lbs+ of IRS stuff. If the subframe bushings allow some deflection, this job becomes much easier. This is why Ford installed M12 bolts at one end of the subframe from the factory. It added enough slop to make the installation easier.
The $332 cost savings quoted is pure fiction. It is made not using the actual MM component prices. It is made comparing oranges to apples in terms of products. When one accurately compares the prices of the various IRS kits, in some cases the MM prices are lower, in some the FTBR prices are lower, but this is primarily a function of how the products are grouped. In most cases it is not possible to do an apples to apples comparison.
____________________________________
Jack Hidley
Maximum Motorsports Tech Support
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This made me laugh. I am an installer for FTBR and have plenty to comment about on this, but am short on time at the moment to correct MM's points of concern and false info, hopefully Bruce will Chime in. First off though, i have never had to use a ratchet strap or excessive force to install any on the FTBR items, or to reassemble and install the IRS with any of their concerns from hard material bushings. second off, the tools rented from FTBR that cost $70, you get refunded $60 back on return. :nonono:
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