newbie to 931, (and 924/944) many questions

palle7688 · 10-28-2004, 08:08 PM

I've been running a 911 for 10 years but need a winter car and have been thinking of a 931 because of low price vs power.
How is reliability on these cars unmodified/modified( thinking of a '79 170 hp euro model as I'm living in europe)??
I've heard that it's easy to modify them to +200 hp, how much boost can you safely run?
How much power has any of you made on a 931 and what did you do to accomplish that?
Has anybody installed a supercharger on a 931?
What are differences between the 931 and 924/924s/944?(transaxle/gearbox/brakes/suspension/enginemounts/other?)
Can you modify the brakes to 951?
What are widest tires front/rear you can run without adding flares?
Any other ideas are welcome:-)
As you can probably read from what I ask, I like to run it fast and perhaps regulary at tracks.
951 is out of the question because of the stupid Danish tax system.
Thanks Palle

Rmills944 · 10-29-2004, 05:07 AM

A supercharger and a turbo? That's an interesting thought.
The 931 is a 924 turbo. The 924 was a 2.0L engine. The 924s is a 924 body on a 944. The 944 is the 924 with a new engine (163Hp and new suspension). The 924 Turbo is not any faster than a stock 944. If you want to mod it, I'm not sure what's out there for a 924, but the 944 doesn't have much that you can do to raise the power easily and cheaply. A supercharger is made for the 944, and it'll get you to about 240Hp if you do it right. On the 944, you can run a 9" in the back and I'm not sure about a 9" in the front, but an 8" works fine up front without a problem (with the right backspacing). That would allow about a 245 front and a 255 rear at least. I have 225's all around on my 7" wheels now and they look great.

palle7688 · 10-29-2004, 01:43 PM

Ok, thanks that much I did know (except from wheel info)
I wanted some more insider/technical specs, like fitting 951 brakes to 924T, is 931 gearbox the same as 944n/a or 951 and transaxle? if not will a 951 gearbox fit a 931. Did 931 come with lsd as std? and so on.

Conc. supercharger, I've about toyotas using both super- and turbo chargers, that would give you instant power from low rpm from the supercharger and high output from turbo, with less turbolag.

Any ideas as where to get more info on tuning these engines, other forums? (sorry Wayne, but it seems like this forum is not as active as the 911 forum, which I think rocks:-))

scottmandue · 10-29-2004, 02:22 PM

Well the 944 gets no respect and the 924/931... (if you can't say anything nice)

The HP numbers you are quoting seem a little optimistic, even for a euro model, those look more like the 2.5 numbers not the 2.0 turbo. Many people are not enthused about moding 944's... even less the 924.

Okay enough with the negativity, try:

www.924.org

They should be able to help, just not a bunch of 924 folks here.

Best of luck.

palle7688 · 10-29-2004, 03:39 PM

I did not intend to upset you or anybodyelse, I think they are great cars! which is also the reason for my interest. The 944 is more expensive if you compare power vs price, at least here in Denmark.
The hp figures is from a Swede who has an intercooler and some other stuff on and claims +40-50 hp for what he says is installed in an afternoon.
It's just I've been on 911 technical forum for some time and I'm sure this kind of question would have given more replies there.

scottmandue · 10-29-2004, 04:11 PM

No offence taken, I guess what I'm trying to say that here in America we don't have the tax laws you do so the 2.5 engine in the 924S and 944 is prefered here.

Honestly have not seen much posted at this board about the 931. However the folks over at 924.org seem to have a lot going on. They are a neat car and I'm glad to see people are saveing them.

palle7688 · 10-29-2004, 04:58 PM

I'll check 924.org, thanks.

Wolf1 · 10-29-2004, 05:50 PM

Quote:

Originally posted by palle7688
I wanted some more insider/technical specs, like fitting 951 brakes to 924T, is 931 gearbox the same as 944n/a or 951 and transaxle? if not will a 951 gearbox fit a 931. Did 931 come with lsd as std? and so on.

It is possible to fit 944 spindles on the 931, so I would guess brake upgrades are possible as well.

The 79 931 that you are looking at should have the "snail shell" transmission. This is a Porsche built transmission rather than the Audi unit used in later 931's and 944's. A standard 944 unit can be installed with replacement of the torque tube and shifter rod. Some modification to or replacement of the torque tube would also be required as they mount differently. Later 931's used basically the same trans as the early 944 and would be a direct swap.

LSD was optional on 931's with both transmission styles.

Boost levels can be raised significantly with the installation of an intercooler.
Without an intercooler detonation will occur at around 12-14 psi of boost. Several people claim to run 17psi without an intercooler (not sure how).

Good luck!!!!!!!...

fast924S · fast924S's Garage

You might want to check rennlist out too, Lots of people on there and always a new topic. You can run nitrous on a turbo car to help spool up the turbo alot faster and its cheaper then adding a supercharger