I understand your points now. Makes perfect sense the way you re-explained it.
Edited to add: Just because it makes sense, don't mean I agree with you.;-)
Edited to add: Just because it makes sense, don't mean I agree with you.;-)
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03-04 Differential Girdle Cover
- Thread starter TVSCobra
- Start date
so,in regards to pistol whip's comments about his cover vs. a diff brace. if we already have a diff brace, what benefits would there be to switching to one of these covers? i'm guessing the fore cover would be lower profile than the diff brace, but from a strength standpoint would a stock cover w/ a diff brace really be as strong? it just seems like a cover like fore's would be overall stronger as there is more strength around the entire piece as opposed to the diff brace which doesn't cover the entire perimeter of the oem cover.
No. What keeps the other half of the housing, that has no brace on it, from deforming? :shrug: As I stated in my previous post, the housing does spread as the ring gear and diff TRIES to go toward the drivers side under acceleration. A FULL cover that is strong and rigid will limit this more than a brace that only covers half the differential. We are probably talking about less than a hundred thousands of an inch, but as you make more power and increase traction these numbers increase....until something breaks :burnout:
You got it! There is definately more strength in having one solid piece covering the whole differential and the carrier pre-load bolts in the cover are icing on the cake and very beneficial. IMO....the best of both worlds.
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Once again, I totally disagree. I think your trying to compare apples to oranges here. I'll try to explain my above post more simply. The billet cover will obviously be stronger as a whole (theres no question of that), than the sintered aluminum (stock) cover. HOWEVER, the question you should be asking is whether or not the added strength is addressing the specific problem. As I stated above, the reason the dif covers break on IRS Cobras is due to the weak mounting point. The carrier does not cause the breakage, nor do the bearing caps or their deflection. The rotating force applies torque to the carrier, its transfered into the housing itself. Since the carrier doesn't give (not do its bearing caps), the housing will twist. The housing is mounted to the IRS sub frame, which is steel, through the mount on the cover which is sintered aluminum. The aluminum is obviously weaker than the steal so when torque levels reach a point of failure, the cover flexes beyond failure and your left with a broken dif cover and most likely other damage due to the housing now being out of proper alignment since the rear mount just broke.
Now that you know that, what do you think is more important to strengthen? The entire cover marginally, or the section of the cover that mounts to the steal sub frame extensively? Knowing that rotational torque is applied in ONE DIRECTION and is technically creating pressure at the mounting points, you only benefit from the added strength on the mounting side itself. The IRS brace disperses the load of the rotational torque through the entire housing rather than just applying to the mounting point itself like the factory design does.
As I stated before, the billet cover is nice for the fact that it allows a better mating surface to the housing and will be more rigid over time. It will eliminate leaks from eventual flexing and wearing of the housing itself and will strengthen up the open area of the housing. However, I still think that the IRS brace itself is a better solution to the dif cover breakage that these cars experience.
If the mounting point of the billet cover is a complete, solid peace of billet (meaning not hollow or milled on the inside) I can see it being just as, or stronger than the brace. If it's hollow on on the inside, I think you going to have the same breakage issues as you had with the stock peace.
Bottom line, the brace works and solves the problem that these IRS's suffer from. If I can put the brace on the billet cover, I'd get one. If not, I'll stick with what I have. My opinion of the bearing cap pre-load bolts remains the same. I don't believe that they increase housing strength at all and I see them more as a gimmick than a productive peace of equipment.
I'd like an explanation on how a set of 10 or 11 mm fine thread bolts screwed into aluminum threads, will apply any more holding pressure to a bearing cap that is already held in place by two grade 8 15mm course thread bolts bolted into nodular iron. Keeping in mind that once again as you stated, the carrier is having rotational torque applied to it and its walking TO THE DRIVER SIDE, not out the back. Sorry, I don't buy it.
Now that you know that, what do you think is more important to strengthen? The entire cover marginally, or the section of the cover that mounts to the steal sub frame extensively? Knowing that rotational torque is applied in ONE DIRECTION and is technically creating pressure at the mounting points, you only benefit from the added strength on the mounting side itself. The IRS brace disperses the load of the rotational torque through the entire housing rather than just applying to the mounting point itself like the factory design does.
As I stated before, the billet cover is nice for the fact that it allows a better mating surface to the housing and will be more rigid over time. It will eliminate leaks from eventual flexing and wearing of the housing itself and will strengthen up the open area of the housing. However, I still think that the IRS brace itself is a better solution to the dif cover breakage that these cars experience.
If the mounting point of the billet cover is a complete, solid peace of billet (meaning not hollow or milled on the inside) I can see it being just as, or stronger than the brace. If it's hollow on on the inside, I think you going to have the same breakage issues as you had with the stock peace.
Bottom line, the brace works and solves the problem that these IRS's suffer from. If I can put the brace on the billet cover, I'd get one. If not, I'll stick with what I have. My opinion of the bearing cap pre-load bolts remains the same. I don't believe that they increase housing strength at all and I see them more as a gimmick than a productive peace of equipment.
I'd like an explanation on how a set of 10 or 11 mm fine thread bolts screwed into aluminum threads, will apply any more holding pressure to a bearing cap that is already held in place by two grade 8 15mm course thread bolts bolted into nodular iron. Keeping in mind that once again as you stated, the carrier is having rotational torque applied to it and its walking TO THE DRIVER SIDE, not out the back. Sorry, I don't buy it.
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IRS Cover
Problem is the IRS Brace doesnt work 100%. I know quite a few people in my area that have had the re-end crack even with the Billetflow IRS brace on and it still leaks. So is it worth a shot for something else that may work?
In my opnion yes has to be stronger than the IRS brace. Only time will tell once these are relased.
Problem is the IRS Brace doesnt work 100%. I know quite a few people in my area that have had the re-end crack even with the Billetflow IRS brace on and it still leaks. So is it worth a shot for something else that may work?
In my opnion yes has to be stronger than the IRS brace. Only time will tell once these are relased.
First of all I just want to say I'll be the first to tell you I don't know everything and really enjoy learning. I enjoy these kinds of discussions and I have nothing to prove. I don't work for any parts company and only want the best parts for my car. I could really care less if they said Tonka on them. Hey Pistolwhip....thanks to your previous post I rode 45 minutes home from work yesterday and didn't even turn on the radio.....I just pondered your comments 
We established earlier that there is a force on the bearing caps toward the rear AND drivers side of the car right? The ring gear is pushed back AND toward the drivers side. If we were able to look at the vector forces we would probably have a resultant force that would be directed more toward the drivers side exhaust tip, but for the ease of this conversation just know that there is a force exerted on the bearing caps toward the rear of the car. The only thing holding that carrier in the housing (excluding the axles here) is those 4 bearing cap bolts, which are taking the full brunt of that force.....right? If I add ANY mechanism (like the pre load bolts) to take some of the load off these 4 bolts, haven't I DEcreased the chances of those 4 bolts failing? Kinda like this.....if you are exerting a force to move a disabled car and a buddy comes along and adds ANY amount of force in the same direction as you, doesn't that make your job easier? Another thing that these pre load bolts help with is stabilizing the bearing caps. In reality they move around ever so slightly and these bolts make them act more as one piece with the rear end. In essence they are now more like one whole piece. For my car I would also like to put billet steel bearing caps and replace the stock diff cap bolts with studs just to add another degree of strength.
You are correct in your statements about the stock IRS cover. I would agree that most likely the #1 cause of the IRS cover failures is due to torsional (rotational) forces on the housing coupled with the mounting location on the rear cover. I'll buy that. The center section is trying to turn due to being hooked up to the driveshaff and that stock rear mount is trying to stand up and say "OH no you don't." That equals broken diff cover at some HP and traction level. Also, diff bushings other than rubber will keep the housing from moving as much and putting as much load on the rear cover mounting point.
On to the brace setup you are running. With your setup, where does all that torsional load we just discussed go now with that steel brace on the rear mount? The force mostly goes into the 5 or 6 bolts (depending on brand) that attach the brace. This setup is a definate improvment over stock no doubt, but wouldn't it be better to spread that load over all 10 of the rear diff cover bolts? You are correct about the rear mounting point....if it is hollowed out it might not be as strong and that could become your weakest link. To hollow out that mount point would not be wise engineering. The solid Billet diff cover, done correctly, will spread the load of the torsional forces created by the rear IRS subframe mount over all 10 of the rear bolts (pre load bolts will also take some of this load) which is better than the 5 or 6 used in the steel brace/stock cover setup. Think of the shear (or cross) loading on the these bolts as the cover TRIES to spin off of the diff housing as the housing TRIES to rotate with the driveshaft.
I think these guys are having this problem with the steel brace setup because, the other half of the diff housing is still in stock form (i.e. aluminum cover & bolts) and can still move and deform more than the passenger side with the steel IRS brace. The forces I talked about before are still at work. The ring gear and diff are still trying to exit the rearend somewhere out the back toward the drivers side. As they exert force toward the drivers side carrier bearing on the aluminum diff housing, it will deform. I would be interested to see what is breaking and where they are leaking. I would also be interested in their whole car setup, such as HP levels, tires, gears, etc.
We established earlier that there is a force on the bearing caps toward the rear AND drivers side of the car right? The ring gear is pushed back AND toward the drivers side. If we were able to look at the vector forces we would probably have a resultant force that would be directed more toward the drivers side exhaust tip, but for the ease of this conversation just know that there is a force exerted on the bearing caps toward the rear of the car. The only thing holding that carrier in the housing (excluding the axles here) is those 4 bearing cap bolts, which are taking the full brunt of that force.....right? If I add ANY mechanism (like the pre load bolts) to take some of the load off these 4 bolts, haven't I DEcreased the chances of those 4 bolts failing? Kinda like this.....if you are exerting a force to move a disabled car and a buddy comes along and adds ANY amount of force in the same direction as you, doesn't that make your job easier? Another thing that these pre load bolts help with is stabilizing the bearing caps. In reality they move around ever so slightly and these bolts make them act more as one piece with the rear end. In essence they are now more like one whole piece. For my car I would also like to put billet steel bearing caps and replace the stock diff cap bolts with studs just to add another degree of strength.
You are correct in your statements about the stock IRS cover. I would agree that most likely the #1 cause of the IRS cover failures is due to torsional (rotational) forces on the housing coupled with the mounting location on the rear cover. I'll buy that. The center section is trying to turn due to being hooked up to the driveshaff and that stock rear mount is trying to stand up and say "OH no you don't." That equals broken diff cover at some HP and traction level. Also, diff bushings other than rubber will keep the housing from moving as much and putting as much load on the rear cover mounting point.
On to the brace setup you are running. With your setup, where does all that torsional load we just discussed go now with that steel brace on the rear mount? The force mostly goes into the 5 or 6 bolts (depending on brand) that attach the brace. This setup is a definate improvment over stock no doubt, but wouldn't it be better to spread that load over all 10 of the rear diff cover bolts? You are correct about the rear mounting point....if it is hollowed out it might not be as strong and that could become your weakest link. To hollow out that mount point would not be wise engineering. The solid Billet diff cover, done correctly, will spread the load of the torsional forces created by the rear IRS subframe mount over all 10 of the rear bolts (pre load bolts will also take some of this load) which is better than the 5 or 6 used in the steel brace/stock cover setup. Think of the shear (or cross) loading on the these bolts as the cover TRIES to spin off of the diff housing as the housing TRIES to rotate with the driveshaft.
I think these guys are having this problem with the steel brace setup because, the other half of the diff housing is still in stock form (i.e. aluminum cover & bolts) and can still move and deform more than the passenger side with the steel IRS brace. The forces I talked about before are still at work. The ring gear and diff are still trying to exit the rearend somewhere out the back toward the drivers side. As they exert force toward the drivers side carrier bearing on the aluminum diff housing, it will deform. I would be interested to see what is breaking and where they are leaking. I would also be interested in their whole car setup, such as HP levels, tires, gears, etc.
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The re-end cover cracked right down the middle on one of their cars. And most of them have to keep resealing them bec of leaking. Its leaking where the re-end cover is sealed. Im not saying that you are wrong. I just wanted to inform you that people I know still have problems even with the IRS brace. So Im thinking it maybe time to try something new.
Most of their cars have pulley, exhaust, air intake, and tune. Nothing extreme. 295, 315, 335 tires out back. I mean its basically everything most Cobra owners would have.
Most of their cars have pulley, exhaust, air intake, and tune. Nothing extreme. 295, 315, 335 tires out back. I mean its basically everything most Cobra owners would have.
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