Big Power Rear Diff Help NEEDED

[adamsbees]

Hello,
I have a cd009 swapped 780. I will be putting a 6.0 LS in it soon. The car has IRS. Will the stock diff housing and subframe handle 500HP? (yes I will seam weld the chassis) I just need advice on what rear diff or subframe to use. People have spoken about using the IRS ford 8.8, BMW diffs, etc. But I cannot find anything on them and people who have done them are very secretive :(

Any advice or links to other builds would be hugely appreciated!!
Thanks,
Adam

[VB242]

I think the Toyota IRS fits with some work, Vincent Gagnon put one in but I can't find the thread

[adamsbees]

Originally Posted by VB242

I think the Toyota IRS fits with some work, Vincent Gagnon put one in but I can't find the thread

Okay thank you I will look into it!

[SkeTchy-MechAniC]

Contact bakaxel.se they speak english and should have a solution at hand. They also make some seriously strong internals for the 1041. I was looking for something to handle my 2jz build when it's done and they make a set that's well proven to handle a turbocharged v8. (photo of a 240 doing a wheelie at the dragstrip included).

[940T4R]

Buy a torsen from bakaxel.se

For the same product but with a fast reply and handling you can contact Markus from www.mkmotorsport.se

[culberro]

If you're going big power, why even mess around with anything but a Ford 9":
https://dutchmanaxles.com/products/h...rear-ends.html

[adamsbees]

Originally Posted by SkeTchy-MechAniC

Contact bakaxel.se they speak english and should have a solution at hand. They also make some seriously strong internals for the 1041. I was looking for something to handle my 2jz build when it's done and they make a set that's well proven to handle a turbocharged v8. (photo of a 240 doing a wheelie at the dragstrip included).

Originally Posted by 940T4R

Buy a torsen from bakaxel.se

For the same product but with a fast reply and handling you can contact Markus from www.mkmotorsport.se

Originally Posted by culberro

If you're going big power, why even mess around with anything but a Ford 9":
https://dutchmanaxles.com/products/h...rear-ends.html

bakaxel has IRS stuff? My car has the 1045 I am pretty sure. I was looking at Sander's build thread with the Mercedes v12 745. He uses a bmw diff and modifies his rear subframe for it. I 100% want to retain IRS. Based on what I read I think I will be going with a bmw e32 (750i) rear diff. They have LSD from factory and can handle a lot more torque than I plan on putting out. The stock Volvo axles are a direct bolt on to that diff. It will suck having to remake the rear subframe but I am up for the challenge.

[culberro]

Originally Posted by adamsbees

... a bmw e32 (750i) rear diff. They have LSD from factory and can handle a lot more torque than I plan on putting out. The stock Volvo axles are a direct bolt on to that diff. It will suck having to remake the rear subframe but I am up for the challenge.

BMW LSDs are crushingly disappointing, just an FYI.

[adamsbees]

Originally Posted by culberro

BMW LSDs are crushingly disappointing, just an FYI.

Damn for real? How so?
If that's the case I will have to go with ford and get custom axles. Same amount of work but more $$$

[culberro]

The Ford is just a known quantity and extremely strong.

The BMW clutch pack LSDs have hideously low break away torque, and it's a ton of money to make them work better. They're also really expensive for what they are.
The supra LSD is slightly better than the BMW one, but still suffers from the same design shortcomings.
Best option with the BMW and Toyota diffs is to get a real 1.5/2-way clutch LSD. So you have to factor in another $800-1200 if you go that route.

[adamsbees]

Originally Posted by culberro

The Ford is just a known quantity and extremely strong.

The BMW clutch pack LSDs have hideously low break away torque, and it's a ton of money to make them work better. They're also really expensive for what they are.
The supra LSD is slightly better than the BMW one, but still suffers from the same design shortcomings.
Best option with the BMW and Toyota diffs is to get a real 1.5/2-way clutch LSD. So you have to factor in another $800-1200 if you go that route.

Gotcha, yeah looking at the BMW diff prices made me sick. Thank you for the insight I greatly appreciate it. Gathering from what you said I have 2 options:

1 Find an IRS 8.8 at the junkyard (idk if there is an IRS 9)
2 Get a cheap junkyard BMW diff, let's say just the case and flanges, and then buy a true aftermarket LSD for it

[culberro]

The 8.8 IRS isn't a bad setup at all.
You can get an aftermarket Ford 9" IRS , but they're about $1300 for the case and stub-axles, you supply the center section and half-shafts.

There's also the mk3 supra diffs. A Cusco RS LSD is like $800 usd for those, and they're much stronger than the "medium" case BMW diffs.

[KwikBrik245]

Originally Posted by adamsbees

Hello,
I have a cd009 swapped 780. I will be putting a 6.0 LS in it soon. The car has IRS. Will the stock diff housing and subframe handle 500HP? (yes I will seam weld the chassis) I just need advice on what rear diff or subframe to use. People have spoken about using the IRS ford 8.8, BMW diffs, etc. But I cannot find anything on them and people who have done them are very secretive :(

Any advice or links to other builds would be hugely appreciated!!
Thanks,
Adam

Make a project thread and show that thing off

[adamsbees]

Originally Posted by KwikBrik245

Make a project thread and show that thing off

I will soon. Already documenting it on insta: @adamsvolvo

[mikezohsix]

I have a complete subframe drop out from a 2004 GTO with an automatic.
Had an idea that I was going to adapt the center section into my LS1/T56 powered V90.
My plan was to keep the Volvo hubs, and make "adapter" half shafts.
I didn't want to loose the advantages in ride and handling by going to a solid rear axle.
That rear end took LS power without a lot of internet chatter about it being weak, don't know if that's changed in the last years or not.
Never got into it.

It's complete from caliper to caliper.
How's $150 sound?
I'm in western MA, so 2.5 to 3 hours away.

PM me if you want to discuss.

[mikep]

Originally Posted by culberro

If you're going big power, why even mess around with anything but a Ford 9":
https://dutchmanaxles.com/products/h...rear-ends.html

Originally Posted by adamsbees

Gotcha, yeah looking at the BMW diff prices made me sick. Thank you for the insight I greatly appreciate it. Gathering from what you said I have 2 options:

1 Find an IRS 8.8 at the junkyard (idk if there is an IRS 9)
2 Get a cheap junkyard BMW diff, let's say just the case and flanges, and then buy a true aftermarket LSD for it

9” sucks power due to the pinion angle, but is good for many gear changes.
Dana 44 is similar to 8.8, and is in lots of IRS cars. Older corvettes, for example.

[Jussi Alanko]

If i was you i will go to a bakaxel.se and buy a torsen lsd with 31 splines and then CrMo driveshafts to it, those costs some $$$ but those will hold something about 1250nm at drag car with drag tyres. So with a street tyres it will hold up a 1000 pound feet, which is, if i think this kind of torque in a old volvo it will need some reinforcements to chassis and better brakes etc etc.

[adamsbees]

Originally Posted by Jussi Alanko

If i was you i will go to a bakaxel.se and buy a torsen lsd with 31 splines and then CrMo driveshafts to it, those costs some $$$ but those will hold something about 1250nm at drag car with drag tyres. So with a street tyres it will hold up a 1000 pound feet, which is, if i think this kind of torque in a old volvo it will need some reinforcements to chassis and better brakes etc etc.

Yeah I know the chassis will need reinforcement haha. I’ve seen bmws shear their bodies at 500hp hahaha. So you’re suggesting I upgrade the internals of my volvo IRS MK1 diff. The case will hold? I’m looking to do 600hp 600tq (approx).

[283SD]

Your tires will be the weak, link unless you run slicks.