possibly getting a 924 turbo

rebelgtp · 06-29-2005, 09:56 PM

hey guys i'm new to the boards but not to the world of porsches. i use to drive a 944 and sold it several years ago and have missed it everyday since. today i found a beautiful example of a 924 turbo for sale here local and its even a decent price. what sorts of things should i look out for on this car? what sorts of things can i do to increase the performance of the turbo engine. i know its the same basis as the carrera gt engine and i would love to get it close to that kind of power as time goes on. any tips or suggestions will be greatly appreciated. thanks.

fast924S · fast924S's Garage

Welcome to the board. I dont know much about the 924 turbo aka 931 but Im sure some one will chime in soon

PhillysMostWntd · 06-30-2005, 01:55 PM

i dont know much about 924 turbos, but in most turbocharged cars an aftermarket turbo will almost always yeild more hp.

SlowToady · 06-30-2005, 04:49 PM

Look out for engine trouble. Cracked exhaust manifold, which is pricey and a ***** to get, rust, cracked turbines on the turbo, leaks...same things you'd look for on any performance car. After going through some of the wiring on my 944, I'd say check that out as well. The factory wiring is rather complex and can be easily mucked up. Remember, engine and exhaust parts on a 931 are $$$.

As for perfomance mods, bigger turbo, lighter forged rods, lighter lower compression pistons (and more boost), shaved crank, maybe port the head, cam, adjustable cam gear (if someone makes it). An engine is an engine, you know? Same principles. Also, a large factor in the 924 Carrera GT generating the power it did was the top mounted intercooler. As legend has it, they are extremely rare and command a hefty premium if you ever do find one.

Get a PPI done, and if it checks out, go for it. IMO, they're pretty cool cars. If I could find one in GREAT shape, I'd probably get one. (Only probably because I don't have steady work right now...) Good luck!

Wolf1 · 06-30-2005, 06:44 PM

Quote:

Originally posted by rebelgtp
today i found a beautiful example of a 924 turbo for sale here local and its even a decent price. what sorts of things should i look out for on this car?

First off.

What year of 931 is it?
And how much is a decent price?

rebelgtp · 06-30-2005, 07:04 PM

thanks for the input so far.

its a 1979 silver and black black leather interior both the exterior and interior are in good shape (no splits in the leather no big dents in the body)

its $1600 but they are willing to deal some. most 931s i have found around here have been always around $4000 wich is way more then i was willing to pay (they have all been in alot rougher shape then this one)

Wolf1 · 06-30-2005, 07:21 PM

A 79 931 will most likely have synchro problems in the transmission. Make sure it upshifts and downshifts without any grinding. First and second gears are the first to go. Even if it shifts great, be aware that this trans WILL NOT tolerate any harsh shifting. The trans overall is pretty tough, but the synchro's suck.

A 79 will also come with a bigger turbo than the 81&82 models. It has the ability to provide more boost, but also has a little more lag.

Is it five lug or four lug wheels. This makes a big difference in the braking ability of the car.

Another weak spot on the 79-80 931's is the ignition system, it can be tempermental at best.

$1600.00 doesn't sound too bad if it all checks out ok.

Of coure, a PPI would be a good choice. Simple things like the A/C not working, or an exhaust problem, or clutch issue etc.. could instantly double the cost of the vehicle.

Good luck!!

MoonBoy · 07-01-2005, 11:07 AM

You may want to visit 924.org and the forums there @ http://www.924board.org/ it's not always that active but there are many dedicated 924 enthusiasts there!
Wouldn't a '79 be a Euro model? I thought that US production was started in '80, I've heard of a few '79s but they were euros, which is a good thing becasue the euro models had bigger turbos.

nickd · 07-01-2005, 04:17 PM

Amazing the things you guys come up with...

#1, ignore everything "SlowToady" posted.

#2, this sounds like an excellent buy if it is in any sort of reasonable shape. These models are doing nothing but appreciating.

Wolf1 has a good list of things to look out for. 931's running regular dino oil usually see turbo lifespans of around 30-50k miles. Check the rebuild history. In fact, try to get as much history as you can, as with any model.

Keep in mind that while the purchase price is pretty reasonable, you're definitely going to give the car a serious cash infusion over the first year. It is 26 years old after all.

Best of luck!
nick

rebelgtp · 07-02-2005, 08:46 AM

a little more info on the car it is a 4 lug car wich i would probobly be switching over to the 5 lug setup from a 944. wich as it is there are alot of 944s i'm sorry to say in the local junk yards for me to pull parts from (including front fenders for that whole carrera conversion).

i'm not sure if the 79 was a euro only model but it would explane why i'm having trouble finding some info on it for us specs if anyone can confirm that please do. also if it is a euro model what kinds of issues will i have on registration, getting correct parts etc?

i'm trying to contact the owner this weekend to see if i can go take it for a test drive and check it out. i'm hoping that they say they had the work done at sunset imports since i use to work there i could ask the guys about the car and they were always flat out honest with me.

scottmandue · 07-02-2005, 09:56 AM

Is the stock 79 931 engine the same as the Carrera?

I thought the Carrera had a special factory engine... I could be wrong...and usually am.

rebelgtp · 07-02-2005, 10:25 AM

Quote:

Originally posted by scottmandue
Is the stock 79 931 engine the same as the Carrera?

I thought the Carrera had a special factory engine... I could be wrong...and usually am.

the carreras engine was based off the normal 931 engine. if i remember right the block crank and rods were all the same, i beleive the pistons were differant, it had a larger turbo, intercooler and i think bigger injectors but i'm not 100% on those. i have a parts list of all the carrera specific parts somewhere that i got when working at the dealer. you could build a reasonable copy of the carrera engine at least performance wise. still isn't the real thing but hey its still gonna be fun

Wolf1 · 07-02-2005, 07:50 PM

Here is a little bit of info on the various 931-937 models.

924/944 info

1.2gees · 1.2gees's Garage

I'm suprised to see a 4 lug 924 turbo, I remember something about how all 924 Turbos had the same brake set-up as the early 944 NAs...

Anyway, be careful about the purchase and try to stay objective looking at the car as with all (and especially older ones) Porsches, cheap purchase price does not always mean a good buy or cheap running costs. 924 turbos have a fair amount of unique parts that can be hard to get. If your goal is 250+hp, you're far better off getting a 944 turbo.
Ahmet

Tishabet · 07-04-2005, 12:07 PM

Quote:

Originally posted by nickd
Amazing the things you guys come up with...

#1, ignore everything "SlowToady" posted.

Best of luck!
nick

What's wrong with what slowtoady posted? Looked mostly like decent advice to me....
Where in Cambridge are you? I live in Arlington and work near the Museum of Science.

scottmandue · 07-04-2005, 12:51 PM

Sorry for the OT

Grant, do you ever go to the museum of science, did you see the magic exhibit?

Tishabet · 07-04-2005, 01:46 PM

I do go there from time to time, but I missed that exhibit. Were you in town for that one? If you're ever back, I'll buy you a beer or three.

scottmandue · 07-04-2005, 02:30 PM

I work for the science museum in Los Angeles so I helped install that exhibit (we own it).
Love Boston, great people, great history, next time I'm out that way I'll let you know.

Okay back to 931 talk.

Hey, can I turbo my 944?

Buddy · 07-04-2005, 08:59 PM

Five bolt was still an option on the early 931's. It it's a euro version, wouldn't it have the fog lights built into the bumper?

A good running 931 should easily outrun a 944. And yeah, the synchros are usually trashed and very expensive to replace, if you can find them.

nickd · 07-05-2005, 06:48 AM

That post just doesn't have much to do with 931's- or many turbo cars in general.

The manifolds can and do crack, but anyone who knows what they're doing welding cast iron (much different than steel), can patch it up. Several members have welded manifolds and have had no problems with them.

Rust- never happens unless there has been a bad repair job. These models are galvanized 100%.

Cracked turbine blades? Only happens to any turbo if debris enters the combustion chamber. I've never seen it happen on a 931. Of course, mine was an exception since I melted the alloy pistons and molten aluminum chewed up the blades... most people don't have that problem!

Bigger turbo- the stock K26 should be able to breathe just fine until over 250hp. Few people shoot for numbers higher than this. 931's have a unique turbo which lends to some difficulty when wanting to upgrade, basically, you can't change the hot side at all.

Forged rods? Who outside of pro racing using these? They something like $1500/set through Pauter/etc. and have no benefits on the street.

Less compression and more boost, also makes for a terrible street car.

Shaved crank? More track car territory...

Ported head- doesn't hurt, but gains will be minimal.

Cam- pointless on any turbo until you're maxing out the stock cam, which takes a lot, or you want to move the power band up- another track feature.

Adjustable cam, pointless.

With a 931 the first step is to pick up a boost controller, you can safely run 8-9psi (stock US is 4-6) on premium fuel. That automatically bumps you up to ~175hp range. Top mount intercoolers are very inefficient and you have to cut a hole in your hood. Though, you will see a solid 210hp with one. Front mount IC is really the next step, though very tricky to install. You can see ~230hp range still on the stock CIS. Above that, EFI is the next step.

PS- I'm right in the heart of Inman Square, haven't made it to the science museum yet although it's just around the corner! Hope you enjoyed yesterday's fireworks :-)

nick