Wondering: S Type-R with twin screw

[boomerkk]

Been reading NormanD's postings re: twin screw conversions.

Also saw the hype around Arden's twin screw kit...

Noticed that good S Type Rs are hovering around the 10k mark nowadays and set me wondering, can the newer 6-speed autobox take 550hp (something like NormanD's setup) in their stride?

NormanD's using the older 5-speed auto tho.

[NST]

the 6sp is rated at around 460ish lb/ft.. (XK/F R the 6HP-28 is rated at 700nm, though the safe limit is probably close to what jag have limited the torque to.. Audi have also limited the torque on the RS6 V10 as they both share the same family of ZF autos.

looking at the blurb, Jag have strengthen the the standard 6HP-28 ZF to cope with the extra power..

maybe the Merc 5sp can handle more torque?

[a8hex]

I know when the SLR came out there were questions from some of the Rags about why it only had the old 5 speed box when Mercedes had a newer 6 speed one and the response was the old one could handle all that tourque and the new one couldn't. No idea what MB are doing these days.

[boomerkk]

Thanks for info.

Looks like the old 5-speed seems a much safer bet, apparently it's the same gearbox as in the McLaren SLR, and the cars with the biggest torque - AMG SL65 and CL65.

[NormanD]

From what I was told some time a go was that the 5 speed would take more power than the 6 speed
Maybe that getting six gears into the box thay are that much slimmer so not so much meat to take the load.

I have since put a 4.2 Lt engine in but kept the 5 speed box.

[boomerkk]

NormanD said:

From what I was told some time a go was that the 5 speed would take more power than the 6 speed
Maybe that getting six gears into the box thay are that much slimmer so not so much meat to take the load.

I have since put a 4.2 Lt engine in but kept the 5 speed box.

Thanks. Just the man I'd like to get some insights from.

Was it a major or expensive job to put the 4.2 in the MkI XKR?

MkI prices seem very attractive to me, and I'm seriously intrigued by the prospect of replicating what you did to your car to a certain extent.

I've also seen a few supercharged 4.2 engines for sale around 3k-4k mark, they don't seem particularly hard to source.

From reading about it, the MkI XKR is already a supercar is standard guise but with a twin-screw 4.2 it's probably well into hypercar realm (like yours).

p/s
I come from ownership of high hp Japanese machines but the prospect of climbing up several steps of the priviledge and class ladder into a big cat is very exciting.

[NormanD]

boomerkk said:

NormanD said:

From what I was told some time a go was that the 5 speed would take more power than the 6 speed
Maybe that getting six gears into the box thay are that much slimmer so not so much meat to take the load.

I have since put a 4.2 Lt engine in but kept the 5 speed box.

Thanks. Just the man I'd like to get some insights from.

Was it a major or expensive job to put the 4.2 in the MkI XKR?

Bob, eMail sent

eMail returned, please email me

Edited by NormanD on Thursday 9th April 23:00

[boomerkk]

NormanD said:

boomerkk said:

NormanD said:

From what I was told some time a go was that the 5 speed would take more power than the 6 speed
Maybe that getting six gears into the box thay are that much slimmer so not so much meat to take the load.

I have since put a 4.2 Lt engine in but kept the 5 speed box.

Thanks. Just the man I'd like to get some insights from.

Was it a major or expensive job to put the 4.2 in the MkI XKR?

Bob, eMail sent

eMail returned, please email me

Edited by NormanD on Thursday 9th April 23:00

Thanks! updated my email and email sent to you.