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Re: Building the supercharger to the engine (75 3.0V6)

Posted: Sun Oct 13, 2013 12:11 pm
by gtv-racer
Haven't checked any thing so far. My 916 is in for a big checkup . Almost done. Then i'm gonna disassamble the 75.
I'll post the pics.

Wonder how you reinforced the components. I'm gonna have a good look at that also!any pics of that would be of great help! Or maybe somewhere i can look on the web.

Still a question how much nm of torque i have but it could be in the 450nm range i geuss. Don't know the numbers for the 3.7.

Maybe greg can give a more accurate estimation of it. 0.6 bar with high lift cams and a peak of 0.7bar. 16.250 supercharger rpm at redline and original compression. I know it's hard to give an accurte figure. Still didn't dyno...

Re: Building the supercharger to the engine (75 3.0V6)

Posted: Sun Oct 13, 2013 1:32 pm
by Giuliettaevo2
The gearbox om Kevin's pic is from a 928. :wink:

Re: Building the supercharger to the engine (75 3.0V6)

Posted: Sun Oct 13, 2013 11:30 pm
by gtv-racer
I know. I have the same :wink:

Still wierd that it does not fit the dedion. Looks so short :?

Re: Building the supercharger to the engine (75 3.0V6)

Posted: Mon Oct 14, 2013 12:12 am
by kevin
To be honest , I has was hoping to do far less work when doing that 928 conversion but if you go up high enough with box and cut huge tunnel and under the gtv tank etc you will get the clearance and the torque tube will be straight . As I said its weird I did not want to do all that work then but ended up doing it any way when fitting the 119 diff five years later :oops: maybe because I had a spare car and could abort the job anytime .
I'm not sure of torque on my car but had 192kw on wheels at 6000ft above sea level . I doubt the torque is anywhere near yours .
Check these guys out
http://www.artracing.co.uk/parts-and-services/

Re: Building the supercharger to the engine (75 3.0V6)

Posted: Mon Oct 14, 2013 3:22 am
by Greg Gordon
Those transaxle and suspension parts really look good. The lack of pricing is a little scary though.

Re: Building the supercharger to the engine (75 3.0V6)

Posted: Mon Oct 14, 2013 7:24 am
by gtv-racer
kevin wrote:To be honest , I has was hoping to do far less work when doing that 928 conversion but if you go up high enough with box and cut huge tunnel and under the gtv tank etc you will get the clearance and the torque tube will be straight .
The 3.0 75 has the tank in the trunk. And i think the tunnel is big enough. Those donust aren't small either :?
Only thing is the shifter machanism but i think it can be lowerd a bit.

Re: Building the supercharger to the engine (75 3.0V6)

Posted: Mon Oct 14, 2013 7:53 am
by gtv-racer

Re: Building the supercharger to the engine (75 3.0V6)

Posted: Mon Oct 14, 2013 7:56 am
by 75evo
I'm just curious, is it not possible to get a custom made ring and pinion? Or a modified pinion with a customized ring? Seems like it won't be cheap, but much less work than a whole new setup.

The center spacer which holds the bearings in the gearbox is also weak. That should be machined out of a solid block of aluminum. I've had 2 fail on mine.

Re: Building the supercharger to the engine (75 3.0V6)

Posted: Mon Oct 14, 2013 8:10 am
by gtv-racer
I heard a lot of things go bad at a certain torque. Pinion can be given a new heat treatment if you know the exact material. Then there's the imput chaft that's gonna break...

Re: Building the supercharger to the engine (75 3.0V6)

Posted: Mon Oct 14, 2013 9:29 am
by Mats
You are talking insane amount of money now, custom parts are crazy expensive for hypoid gears. Especially if you only want one.
To re-heat treat a finished gear sounds like a bad idea, the surface of the gear faces will be wrong and the risk of material structural changes are huge. Not sure what a new heat-treat would add either.

Yes, I'm against it. Unless you have the dough to spare, then I'm totally for it if I can get in on the action for the piece price ex setup/tooling/misc one time cost... :)

Re: Building the supercharger to the engine (75 3.0V6)

Posted: Mon Oct 14, 2013 10:23 am
by 75evo
Damn, forget it then. That guy in Norway with the GTV6 3.2 TT has a selholm + volvo diff. But that box alone costs at least Euro 6K or so. Plus all the other stuff, sounds like Euro 15K project to get it working right. So go ahead with the 928 gearbox :D

Re: Building the supercharger to the engine (75 3.0V6)

Posted: Mon Oct 14, 2013 10:46 am
by Mats
Sellholm box up front then? Never seen a Sellholm transaxle. He does mostly Rallycross parts. The gearbox is actually sourced from the UK I believe.

Re: Building the supercharger to the engine (75 3.0V6)

Posted: Mon Oct 14, 2013 11:24 am
by Giuliettaevo2
That's the speedhunters GTV6 with 600 bhp with the sellholm box.

that box is in the back, hanging in a kind of cradle with a volvo diff right behind it. pics are on the Alfabb somewhere. :wink:

Re: Building the supercharger to the engine (75 3.0V6)

Posted: Mon Oct 14, 2013 11:32 am
by kevin
Isn't it a drenth box in that car .( speed hunters)
What clutch set up are you gonna use with the 928 box . That's also a lot of work up font .

Re: Building the supercharger to the engine (75 3.0V6)

Posted: Mon Oct 14, 2013 11:57 am
by Mats
The article claims Drenth gears in a Sellholm box. Seems strange but I guess he has his reasons.