6-speed 930??

[sjd]

Anyone have any information on practical issues of fitting 6-speed gearbox to 930. I have an old "Porsche & 911" article where a turbo 6-speed box (plus 4 wheel drive) was fitted to a 1993 964 and know that 5 speed G50/50 is a standard upgrade.

It may sound a bit mad, but basically it all seems to boil down to comparative length of 6 speed box to 5 speed and how much, if any, work needs to be done to floor pan to get it to fit.

John Ward knows the car it is running circa 500bhp/500+llbs torque on a cold day. I have read-out of 478bhp/505llbs on G-Force rolling-road, but they thought it was down as it was running hot! It has a standard 4 speed box with LSD and low ratio ring and pinion. This was great to about 420-450bhp, but geared to max of 150mph it is now a bit of a handful at 100mph when you put your foot down and could do with some extra cogs.

(NB currently waiting for poly-bronze bushes for front a-arms to arrive from US and also to fit 935 rear spring plates if anyone interested in outcome)

many thanks for any input
Simon

 

[John_Ward]

Simon
That 930 of yours is just getting more extreme - and I presume that it's still looking like a standard 911 turbo.
I haven't got a clue about your gearbox question, but have no doubt that you will solve it; just remember to keep making notes of why, how and what you did, and keep taking pictures too.
Cheers
John

 

[nathan 1981 930 G50]

I think really that the 6 speed may be too weak. The G50/50 and also the G50/52 are the strongest boxes that were made.
A 50/50 will not bolt straight in a 930 either. What year is your car ? Add it your signature as it helps if you ask questions.

To get the 6 speed in you will have to do away with the rear torsion bars and convert to coil overs only. Maybe you could ask someone to measure how wide the box is at the nose end to make sure it will go in between where the rear banana arms mount.
A lot of metal would have to be cut away from the car and also some work done to make suitable mountings for it.
The end cover of the box would also be a problem. Maybe you could have any excess cut off the cover and have something welded onto the bottom of it so that studs come out the bottom of it to resemble the 915,930,G50/50.
Maybe the box could be fitted with the end cover as it is if you were not worried about losing or disrupting rear cabin space.

It can be done. Of course it would be easier to move your engine into a 3.3 965 that has a 50/52...

Would love to see pics and details of your car, it sounds great.

 

[sjd]

Thanks for all the input.

John - yes it does still look standard and still looking to see what the guys in the US are up to - the poly bronze a-arm bushes look like a good upgrade and I will do you a piece to let you know how I get on.

Maurice - you are right RUF did both a 5 and 6 speed compact. Buying one is a problem, the cost of fixing it when it breaks is even worse. However, the fact that RUF could squeeze the 6 speed in has spurred me on to keep exploring.

Nathan - I do have coil-overs so can cut the torsion tube if need be. I take your point re strength of boxes, but understand you can use turbo 4 box in 2 wheel drive mode. If this is strong enough for standard 409bhp, I figure it must be up to the job. I think this will all come down to measuring a G50/50 and a 6 speed. Have added signature so hopefully you can get an idea of the mods so far.

 

[nathan 1981 930 G50]

I see your point about it being strong enough for the car it came in as standard. Also our cars are lighter (the 993 is the heaviest 911 of them all).

I thought this too but actually we are wrong. Something in the 6 speed bends when used hard.

 

[nathan 1981 930 G50]

MoC2S, Yes, I think that sounds familiar.

I've heard that even the 996tt's ecu reduces power in the lower gears to save the manual transmission. Supposedly getting it remapped makes a big difference to performance. I wonder if the 996GT2 box is stronger.

sjd, Your car sounds great. I would like to do the cams in mine sometime or get the heads ported. My mods are just bolt ons at the moment and are still not complete []
Who do you use for insurance ? I'm currently with Heritage but was happy with AON previously.

 

[sjd]

Nathan - I use Heritage (as for the last 8 years).

I thought about porting the heads, but read that Porsche did a pretty good job as standard. I would go for the 3.4 higher compression ratio pistons and barrels in preference as they also have better cooling fins etc. (but big money!).

The 964 cams were done with engine rebuild by Bob Watson. I have found these great. I now hit the rev limiter at 7k revs with no effort and looking at the power graph Ithis shows 473bhp at 5200 revs which is held until about 6300 revs. This was with boost at circa 1.1bar.

If you are at Eynsham on the Sunday look me up and I can take you through the highs and lows of £15k+ of bills on mods.

regards - Simon

 

[sjd]

To finish this 6-speed link I can confirm I have been speaking directly with RUF. They no longer make the 6 speed short box, but did have their technical unit look at a 993 box conversion, but at Euro 25,000+ they thought it too expensive. No kidding!!!!!!!!!!!

 

[nathan 1981 930 G50]

I won't be at Eynsham []

Would using higher compression mean you would have to use lower boost as our fuel is not that great ?

Everything is big money [:'(]

Why not settle for a G50/50.

Did you upgrade the rod bolts ?

 

[sjd]

Higher comp can lead to earlier detonantion - so yes would need o take care on boost pressure. I use super unleaded with a full bottle of NOS fuel additive per tank, This gives min 100 octane rating (higher if I fill up with Shell optimax).

I will look at G50/50.

I did not upgrade rod bolts (they should be good for 500bhp), but did fit later head bolts.

Simon

 

[Tankman]

You could always look at something like the Patrick 5 speed close ratio racing box I have on mine as an alternative. The site is here . . .

[FONT=Trebuchet MS"]Patrick

 

[nathan 1981 930 G50]

Marc, did you buy the gearbox from them ?

It seems to me they are a terrible company to deal with, they do not return phone calls or emails and this is when I am enquiring. Imagine if I had a problem...

Someone in the USA quoted him as being a jerk, although I thought that was going too far.

I cannot seem to find what your 510 & 563 are. Are they options ?

 

[sjd]

Patrick

Thanks for the tip - despite Nathan's comments I have used Patrick Motorsport for parts before and found them very helpful.

What sort of money did your box cost - is it based on the 4 speed? Can you also let me know what gearing you are using - e.g. what is it maxing out at?

many thanks
Simon

 

[nathan 1981 930 G50]

I'm glad that you received good service, maybe there is hope.

Here is a link http://forums.rennlist.com/rennforums/showthread.php?t=295248&page=1&pp=15

What did you buy ?

I emailed Patrick Motorsports about 4 years ago and also 4 months ago. They have never returned the emails. I telephoned them 4 months ago twice and was promised each time they would return my telephone call (the chap was not available each time I rang), they never did [&o].

I like the look of their lightened flywheel for my 3.2 carrera if I do refit the 915 back into the car.

 

[Tankman]

ORIGINAL: nathan 1981 930 G50

Marc, did you buy the gearbox from them ?

I cannot seem to find what your 510 & 563 are. Are they options ?

Nathan, The car had all the work done on it by a previous owner so I cannot comment on the buying process from Patrick. However, I did find them very helpful when I contacted them.

Those numbers are not options check the Dyno link below

Dyno

Regards

Marc

 

[Tankman]

ORIGINAL: sjd

Can you also let me know what gearing you are using - e.g. what is it maxing out at?

many thanks
Simon

Simon,

See the above post re: Cost etc

Regards

Marc

 

[nathan 1981 930 G50]

Sweet dyno, I am jealous [8D]. Was that to the wheels or corrected crank ?

How did you go about contacting Jim Patrick ?

TIA

 

[sjd]

Marc

Nice dyno (I have same print out but "only" 473 bhp and 505 llbs of torque. I'll be interested to see details of your engine spec to acheive the 510 bhp figure. Twin plug, fully electronic ignition and fueling???

regards Simon