Girdle needed? Benefits?

90tbirdsc

Registered User
Hey guys I was just wondering if my tbird could benefit from a rear end girdle? I will hopefully be 250-270hp and 350-380 tq at the wheels. I plan to get a cam and ported big valve heads next fall/winter as well. I already have the 3rd member out and figured it would be a good thing to put on to help keep everything rigid. My car is a auto as well. Just didn't know if it's worth the $200

Thanks
 
Hey guys I was just wondering if my tbird could benefit from a rear end girdle? I will hopefully be 250-270hp and 350-380 tq at the wheels. I plan to get a cam and ported big valve heads next fall/winter as well. I already have the 3rd member out and figured it would be a good thing to put on to help keep everything rigid. My car is a auto as well. Just didn't know if it's worth the $200

Thanks

I think you are better off upgrading to a stronger differential cover than adding a girdle. I recently put this LPW racing cover on both my SCs and also upgraded to the Performance Art Work rear diff mount and Energy Suspension poly front diff mounts.

http://www.lpwracing.com/Ultra_IRS/Ultra_IRS.html

http://www.sccoa.com/forums/garage_attachment.php?id=3214&attach_type=full

David

At your power level and having an automatic, I don't really think you need to upgrade the cover or add a girdle, but it wouldn't hurt anything.
 
Last edited:
I think you are better off upgrading to a stronger differential cover than adding a girdle. I recently put this LPW racing cover on both my SCs and also upgraded to the Performance Art Work rear diff mount and Energy Suspension poly front diff mounts.

http://www.lpwracing.com/Ultra_IRS/Ultra_IRS.html

http://www.sccoa.com/forums/garage_attachment.php?id=3214&attach_type=full

David

At your power level and having an automatic, I don't really think you need to upgrade the cover or add a girdle, but it wouldn't hurt anything.


David,
Looks like I know where to buy my diff. Cover now lol. (Haven't seen any I like lately)
I see that diff. Brace, is that better to have that, vs. a cover/brace?


Thanks
Steve
 
David,
Looks like I know where to buy my diff. Cover now lol. (Haven't seen any I like lately)
I see that diff. Brace, is that better to have that, vs. a cover/brace?


Thanks
Steve

Steve,

To get more strength from the diff cover you can add a brace/girdle or you can do as I suggested and go to an upgraded stronger cover. Benifits to going with something like the LPW cover are lighter weight, carrier bearing pre-load studs and a drain plug. Control freak and Ford Racing also make upgraded 8.8 IRS covers.

The rear diff mount is a separate issue. You can use a stock mount, a modified stock mount (extra plates welded on/drilled thru and bolted) or you can purchase the aftermarket unit like I did that is much heavier construction and uses a big poly bushing.

David
 
I think you are better off upgrading to a stronger differential cover than adding a girdle. I recently put this LPW racing cover on both my SCs and also upgraded to the Performance Art Work rear diff mount and Energy Suspension poly front diff mounts.

http://www.lpwracing.com/Ultra_IRS/Ultra_IRS.html

http://www.sccoa.com/forums/garage_attachment.php?id=3214&attach_type=full

David

At your power level and having an automatic, I don't really think you need to upgrade the cover or add a girdle, but it wouldn't hurt anything.

I forgot to add that my whole case is allumnium as well as the cover, they guy I bought it from said that 10-15 years ago ford Motorsport made a all allumnium unit that was like $1000 and that's what's in the car. I don't know if that's true or not but i do know that it is allumnium.
 
I forgot to add that my whole case is allumnium as well as the cover, they guy I bought it from said that 10-15 years ago ford Motorsport made a all allumnium unit that was like $1000 and that's what's in the car. I don't know if that's true or not but i do know that it is allumnium.

It would be from a FN10 or AKA Mark VIII.
 
I forgot to add that my whole case is allumnium as well as the cover, they guy I bought it from said that 10-15 years ago ford Motorsport made a all allumnium unit that was like $1000 and that's what's in the car. I don't know if that's true or not but i do know that it is allumnium.

Yes the Ford Motorsports/Racing differential had an aluminum case just like what came on the 99 Cobra. As I recall they sold for around $750.

David
 
Last edited:
My 60 foot in the Mark viii was in the low 1.6s and the car weighed a lot more than a sc. tHotTodd was running low 1.5s and breaking axles from time to time while he was running a 200hp shot to the wheels. Both of us had diff housings with no modifications other than differential and gear. Best bet is to put money into a good set of bushings for your irs, like the upper and lower control arm inners and outers, get it realigned. That way when you start bringing it to the street you dont have to worry about the crazy rear glass breaking wheel hop. If you were close i would gladly help you, i have a Sun alignment machine.
 
My 60 foot in the Mark viii was in the low 1.6s and the car weighed a lot more than a sc. tHotTodd was running low 1.5s and breaking axles from time to time while he was running a 200hp shot to the wheels. Both of us had diff housings with no modifications other than differential and gear. Best bet is to put money into a good set of bushings for your irs, like the upper and lower control arm inners and outers, get it realigned. That way when you start bringing it to the street you dont have to worry about the crazy rear glass breaking wheel hop. If you were close i would gladly help you, i have a Sun alignment machine.

Where you from?
 
Originally, Texas, but been stuck in Va for the last 15-16 years.

Yea definately not close enough to have you help, I'm in the middle of Nebraska. So you can align the rear of the car? That's how I kinda took your other comment about poly diff bushings. I didn't know that you could do that
 
Yeap, one of the cool things about these cars. And, you can set it how ever you like. Simple adjustments make a world of difference on how the car feels.
 
Sweet ill have to look into it, does anyone have a description of how changing the caster and toe will affect handling and launching? Like for example more toe in helps keeping the car straight or something like that:confused: I've done a lot of atv racing and I know the affects of bolth on the front just not how they affect the rear
 
I dont think you could go that far with it. But, you can set rear toe slightly negative say -.10-.15 deg per side and that would shave a little time off due to the deflection of the rear control arms. Ive seen people get away with upto -1.75 deg of camber without any real tire wear. Thats for the rear only. You could do -2.0 deg rear, but dont expect tires to last more than 30k/mi.

I think i just set the front at -1.0camber per side and 0.0 total toe and 5.5 to 6.0 caster per side. When everything is tight, the car pretty much goes straight or where ever you hold it, especially with the rack and pinion steering.
 
Back
Top