924Board.org

phoenix02 · Joined: 16 Apr 2006 Posts: 15 Location: Chino, California

Hello all,
I just won an '81 931 (ebay item number 4630059093 if you want to lookit up). I'm going next weekend to check it out and do some work on it- the seller is going to help me get it back in one piece to make the 100 mile trek home. I was looking for a daily driver car that would be fun, not all too terribly hard to work on, and perhaps when more money comes along, to fix up nicely. I have a few questions-

1-Do you think I got a good deal? The seller is also knocking it down to $550 final price to pay for the smog test. From what I've seen, it looks like a good deal.

2-The engine was rebuilt with 8.5:1 compression, a 1 bar spring installed, and there's a front mount IC included to be installed. on California premium (91 octane) gas, do you think this combo would cause detonation? I need a car reliable enough to not have to rebuild the engine every year or replace the head gasket everytime I do an oil change.

3-Do I need to/ should I put in a water/methanol injection system to negate detonation? Do any of you know if it is california smog legal? I was thinking about designing my own system with the tank hidden in the spare compartment or trunk area and piped up to the engine, so it's pretty much totally hidden. If I do install one, does the injector have to be after the throttle body in the intake to prevent rusting the TB butterfly, or is it okay to be between the turbo and the TB? I've never had a turbo car, so any ideas would be greatly appreciated.

4-Would a K&N CAI kit make any difference over the stock airbox?

5-I'm 6'2" and 300 lbs- do you think I'll have much of a problem in the car? I'v eheard they're roomier than they look. Can anybody give me a comparison interior size? Geo Metro small, Ford Probe medium, Crown Vic large...

I've spent about 15 hours since I bought the car looking at the boards on this website, but have yet to find definitive answers to all my questions.

Thanks alot to anybody that can help me out!
-Michael

Paul · Posted: Sun Apr 16, 2006 8:10 am Post subject:

Welcome to the board and congrats on the 931 (924 turbo).

To best help you, please add at least the state you are from in your profile. I assume it's California....

A 1 bar spring can cause engine damage (think BOOM) so care must be taken. The IC will help but they are a PITA to install.

I suspect you will have a difficult time getting this car to pass emissions, but we are here to help.

Based on the description of the car, you can expect to spend several thousand dollars to bring it back. The first concern is the timing belt since these cars are interference. Even if the seller says it's new, take a look at it before starting the car.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

Smoothie · Posted: Sun Apr 16, 2006 9:10 am Post subject:

phoenix02 · Joined: 16 Apr 2006 Posts: 15 Location: Chino, California

Okay, I'll check out the sheet metal- I just got some cheap Neoprene seat covers, so that'll make 'em easier for me to slide in and out- less plopping down.

As far as the timing belt- I thought the 2.0 was non interference.- are you thinking about the 2.5 from the 944-up, or am I mistaken/ did they change the engine sometime in the production run?

That couple thousand estimate- is that mechanical, or with new interior, paint, etc? If th eengine was just rebuilt and a new clutch installed, I can't see how it could be a couple grand just for mechanicals to get it back on the road... then again, I've never owned a porsche.

Why wouldn't it pass emissions? Are an IC and water/meth injection not smog legal? The reason I even got another car was because my Jag has a '70 motor in a '76 car, so the smog police are giving me all kinds of crap. If something improves emissions/ combustion/ relability (IC, CAI, water injection, etc) it really bugs me that we can't have in Cali. It's like the gun laws- no 50 cal BMG guns here. I can understand not having automatic weapons, but why not a gun that is pretty much good for only target shooting? Is someone going to rob a bank with a gun that knocks you on the butt with each shot and takes 2 seconds to operate the bolt?

I'm sorry for a totally unrelated rant, but it's just an example of why Cali kinda sucks in some respects. I'm hoping to expatriate to another country, like Tennessee or somewhere else in the south some day. only problem is with the lack of un rusted out old cars.
_________________
'81 Porsche 931
'76 Jaguar XJ-12 w/ Chevy 350 from a '70 'Vette
'84 GMC Suburban C-2500

Save your sanity- kick a puppy.
Save your puppy- kick your mother-in-law.

Smoothie · Posted: Sun Apr 16, 2006 11:23 am Post subject:

The 2.0L 924NA is non-interference, but the 2.0L 931(924T) is interference.
_________________
"..it's made in Germany. You know the Germans always make good stuff."

'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

Paul · Posted: Sun Apr 16, 2006 11:46 am Post subject:

You bought the car for the price of the new tires or for about what some have paid to have the turbo rebuilt so you are off to a good start!

The car has the Audi transaxle which is good since parts are available and there's lots of good used ones. A new clutch is a real bonus (parts are about $500).

The ignition system is unique to 81 and 82 931s so certain parts are becoming difficult to find.

A good paint job will cost thousands, a decent interior can be sourced from a younger 944.

The fuel injection system is CIS which hates to be left sitting around. Parts are expensive. It uses 2 fuel pumps, a WUR, a fuel Dizzy, an AAV, etc. Each of these are hundreds of dollars each.

The brake and clutch hydralic parts may also have suffered from not being used. Not cheap either.

Got to wonder why the guy is selling it for 1/4 of the cost of the parts he's put into it....

Hopefully it will start and run and pass emissions, if not you know where we are. We'll do everything we can to help you save a 931!
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

phoenix02 · Joined: 16 Apr 2006 Posts: 15 Location: Chino, California

Thanks alot- it's great to have such a comunity atmosphere here.

Right now, my budget was my tax return- all of $1300- for a vehicle. So far, I have $580 gone for the car, seat covers and a Haynes manual. That leaves me with $720 for the registration, smog, etc. Basically, e-bay and junk yards shall become a friend to me all over again. Does anyone happen to have any of the porsche factory 931 manuals on CD they'd be willing to make a copy of for me, or know of anywhere I could pick them up cheap?
_________________
'81 Porsche 931
'76 Jaguar XJ-12 w/ Chevy 350 from a '70 'Vette
'84 GMC Suburban C-2500

Save your sanity- kick a puppy.
Save your puppy- kick your mother-in-law.

gohim · Joined: 02 Nov 2002 Posts: 4459 Location: Rialto, CA

Welcome, and good luck with your new project. The least expensive places to buy parts are the Pomona Porsche/Corvette Swapmeet at the Pomona Fairgrounds, the Internet, aftermarket parts Sellers from magazine ads, and discounting Authorized Porsche Dealers, not necessarily in that order.

If the engine was rebuilt properly, and the turbo is in good condition, then getting the car to smog should not be a huge problem, as long as the fuel system is not screwed up.

I looked at the owner's eBay ad, and if you looked at the photos carefully before you bid on it, you know that the body needs work, and not just paint.

The engine was rated 156 by Porsche in original form, not 140 as the Seller advertised. The 8.5cr pistoned Euro 931 engines were rated 177. You are going to need to buy a good grade of premium gas all the time.

If the fuel system or ignition system has been hacked, then the $700 remaining in your budget isn't even going to be a down payment.

Don't waste (oops spend) any more money (on worthless cosmetic stuff, until you get the car home and running) until you see the car, and get an idea of what it will need to get it running properly. You are going to have to pay for the DMV transfer, sales tax, registration, smog check, and that's already going to cost you $200 or more.

You will need to buy the Factory Workshop Manual (four volumes) for the 924 AND the 931 (924T) single volume. I got my brand-new (at the time) 931 manual from the Pomona swapmeet for $25. The 924 Workshop Manual that I have also came from the Pomona Swapmeet ($75). Porsche sells the Service manuals on paper, and on microfiche. You can find copies being sold on eBay on CD or DVD. These are all unauthorized, illegal copies scanned and stored in pdf format.

Smoothie · Posted: Mon Apr 17, 2006 12:48 am Post subject:

A few pics to go with my previous post -
Here's the cracked sagging sheet metal below the rear-left seat mount -
http://pg.photos.yahoo.com/ph/smoothies931pics/detail?.dir=/a174&.dnm=fef1.jpg&.src=ph
this shows where to look for it -
http://pg.photos.yahoo.com/ph/smoothies931pics/detail?.dir=/a174&.dnm=66d0.jpg&.src=ph
Here's the torn-out front-right mount -
http://pg.photos.yahoo.com/ph/smoothies931pics/detail?.dir=/a174&.dnm=e59b.jpg&.src=ph
-and repairs viewed from below -
http://pg.photos.yahoo.com/ph/smoothies931pics/detail?.dir=/a174&.dnm=22c4.jpg&.src=ph (some countries require plates of a specific minimum size to be welded in, so the fender washer repairs wouldn't fly everywhere)

If you find you can, and decide to go for water injection, the wiper fluid tank comes in handy for that. I use mine along with a headlight washer pump for an unobtrusive seamlessly integrated

homemade water injection system. (even if you find you can't use it, water injection is way easier to hide or remove-replace than an IC

)

Here's me water injection - http://pg.photos.yahoo.com/ph/smoothies931pics/album?.dir=/3878
_________________
"..it's made in Germany. You know the Germans always make good stuff."

'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

phoenix02 · Joined: 16 Apr 2006 Posts: 15 Location: Chino, California

Thanks alot for the pictures, and the further info on the pomona swapmeet.
I'm really hoping that the car will work out forme- if I start nearing my spending cap, I'll have to just give up and resell it, trying to get what I put out for it. The $1300 is quite litterally all I have to work on it for at least a month. Ya know, perhaps a porsche wasn't such a good idea...

We shall see.
Will water injection give me the same effect as the IC? I thought that they were complimentary, with the IC doing most of the work. Do any of you think that water injection is enough to take care of detonation with the 8.5:1 CR and 1 bar boost? If I go with the water injection and not the IC, how much is it for a stock euro spring if I start getting detonation? Would the euro make all too much difference over the US, or should I just then go with the US spring scavenged from a scrap yard?
If I put the IC on and it fails visual inspection for smog, would I have plausable deniability to say that it was available on the GTS/GTR, which was technically (very, very, very loosely stated) an option package for the Turbo? (I know they're a different car almost all together, but what smog guy will know the diff?) I know that if it can be proven that whatever mods were available for that model year of vehicle, it can normally squeak by.

Now, if you all will close your eyes and bow your heads in a silent prayer to the Porsche Gods-

"lassen Sie bitte dieses porsche das für mich, große porschegötter OH- sein auf Höhe"

(please let this porsche be the one for me, oh great porsche gods on high)
(and if that's wrong, blame google translator)
_________________
'81 Porsche 931
'76 Jaguar XJ-12 w/ Chevy 350 from a '70 'Vette
'84 GMC Suburban C-2500

Save your sanity- kick a puppy.
Save your puppy- kick your mother-in-law.

Smoothie · Posted: Mon Apr 17, 2006 1:46 am Post subject:

Paul · Posted: Mon Apr 17, 2006 3:23 am Post subject:

In order to have any chance of staying within your budget:

Forget about the intercooler, sell it on ebay since your budget will not allow you to install it. (You need to have pipes and hoses fabricated.)

Try to get the stock spring for the wastegate and sell the 1 bar spring.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

phoenix02 · Joined: 16 Apr 2006 Posts: 15 Location: Chino, California

I just looked up the VIN on all the car research sites, and everywhere I looked came up with zero responses. Does this sound right? I thought at least change of title and smog info would be there, if nothing else...

_________________
'81 Porsche 931
'76 Jaguar XJ-12 w/ Chevy 350 from a '70 'Vette
'84 GMC Suburban C-2500

Save your sanity- kick a puppy.
Save your puppy- kick your mother-in-law.

phoenix02 · Joined: 16 Apr 2006 Posts: 15 Location: Chino, California

Okay, I just looked up the VIN on the BAR website- there's no smog info, but the system has been wrong when I've looked up other cars. My question is, if the vehicle was moved in from out of state, I'm concerned with it being able to be smogged. If this is the case, are all 924 turbos 50 state legal, or did they sell a 49 state version without the california smog controls? If there was a 49 state, and this is one of them... I'm kinda screwed.

_________________
'81 Porsche 931
'76 Jaguar XJ-12 w/ Chevy 350 from a '70 'Vette
'84 GMC Suburban C-2500

Save your sanity- kick a puppy.
Save your puppy- kick your mother-in-law.

gohim · Joined: 02 Nov 2002 Posts: 4459 Location: Rialto, CA

Maybe you have the wrong VIN number, or you typed it in wrong.