Shortening a JAG IRS anyone got any experience????
Discussion
retroracing said:
Hi there, wanting to shorten a jag irs by about 4'' per side, does anyoe know anyone who can do this, i'm based in the southwest near bath, also what ballpark figure would i be looking at???
thanks
Ask over on the V8 Forum if you havent already.thanks
But maybe Any Robinson Race cars, Hauser racing etc ?
Or maybe investigate some kit car places who use that axle.
My brother-in-law was always against shortening the driveshafts on the Jag IRS he insisted it weakened them too much,he was twisting the stock S type ones before going over to a narrowed yank r-end(drag racer)problem with the Jag IRS is that failure of these shafts causes the rear end to collapse 
as the driveshaft serves as the upper wishbone/arm support too 
of course it probably depends on how much Torque you intend to stick through them 
he always rated the Jag IRS though and used 1 for years from a Ford BB 390 & Olds BB 455 through to a 454 LS7 Chevy BB around the same time he started twisting them and running out of sources of good used S shafts 
no coincidence there,just added this bit so you get an idea how strong they are 
maybe shortening techniques have improved nowadays though so worth investigating I would think 
as the driveshaft serves as the upper wishbone/arm support too of course it probably depends on how much Torque you intend to stick through them he always rated the Jag IRS though and used 1 for years from a Ford BB 390 & Olds BB 455 through to a 454 LS7 Chevy BB around the same time he started twisting them and running out of sources of good used S shafts no coincidence there,just added this bit so you get an idea how strong they are maybe shortening techniques have improved nowadays though so worth investigating I would think Edited by Simon says on Wednesday 16th February 21:49
Simon says said:
My brother-in-law was always against shortening the driveshafts on the Jag IRS he insisted it weakened them too much,he was twisting the stock S type ones before going over to a narrowed yank r-end(drag racer)problem with the Jag IRS is that failure of these shafts causes the rear end to collapse as the driveshaft serves as the upper wishbone/arm support too of course it probably depends on how much Torque you intend to stick through them
its a 3.5 v8, these diffs are sad to hanlde upto 500bhp so i should be fine lol. I get the point on weakeneing, however you are olnly welding what is welded anyway. I hear the best way to do it is to cut the required amount out the middle press fit a sleeve and weld around the ends, or so i'm told. as the driveshaft serves as the upper wishbone/arm support too of course it probably depends on how much Torque you intend to stick through them 
retroracing said:
its a 3.5 v8, these diffs are sad to hanlde upto 500bhp so i should be fine lol. I get the point on weakeneing, however you are olnly welding what is welded anyway. I hear the best way to do it is to cut the required amount out the middle press fit a sleeve and weld around the ends, or so i'm told.
The props on my dakar are done like that - with a dowel pin as well for good measure:
And these are shafts that go between the gearbox and transfer box on my Dakar:
You can see on the left hand one I tried to fishtail the weld for extra strength.
(Picture actually taken to show the difference between a TH350/700R4 output shaft and the TH400/4L80e - now you can see why everyone uses TH400 in big power cars)
Gassing Station | Engines & Drivetrain | Top of Page | What's New | My Stuff