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Call Me Stupid... Trade 86 Fiero GT for 80 931

Hello guys been a while since on the forum, last known owning a 914. But I have come to a caveat. I have a 80K miler 86 Pontiac Fiero GT with the rare 5 spd that I am thinking on trading on a 80 931. I know how fast my fiero is and like it I know how clean my interior is and like it also. I saw this 80 931 and disliked how the interior was dirty and seats were torn and stained. The car doesn't run. I do know that it has original 50K miles though. Title proves it also. I know the history of the car concurs with the current owners claim, the current owner is the nephew of previous. Previous is 2nd owner of car. So 50K miles, 3 owner 2 of which is family owned. I have reviewed this car and don't know what to do. I am in for the long haul of ownership but would like to see something with appreciating value. Might this car appreciate more than the Fiero? I am also in for something that can produce power. Since this is an 80 it has the old fuel distributor style injection system. This is a reliable system but does it have power potential? Where are the limits of this system? I know a Intercooler would be necessary and possible t3/t4 style cartridge also. What else if possible would be needed? Only other questionable thing is this guy claims that this is a "Anniversary Model" (thought only on 82 was there a anniversary edition), claiming that it is rarer than the norm 931 is this a possiblity? What is another possibility?

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1986 Pontiac Fiero GT 5 Spd 2.8V6
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Old 02-08-2010, 07:05 AM
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The market is small for a 931 as it takes a special buyer to appreciate the car. It is a complicated car with performance on par with a normal 944. Due to the higher maintenance cost associated with the 931 turbo system in comparison with a 944 it is no wonder why so many have fallen by the wayside. The old 931 can be boosted to higher than stock HP numbers though.

I don't think there are many 931 followers here on Pelican but there is another forum out there that caters more to the 924/931 series cars. A fellow Pelican will chime in with the forum name as I can't recall it.

Best of luck,
Speedy
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Old 02-08-2010, 07:24 AM
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Run and run fast the fiero runs and the 931 may never run, Heavy maint involved and you are opening a can of worms. It would be driven now if it didn't have problems.
There have been very good threads about low entry prices on 944's with the same story and major cost involved.
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Old 02-08-2010, 07:34 AM
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I won't call you stupid, because that would make me an absolute ignoramus given the number of 931s I currently own but there are definitely some things to think about before making that trade.

The CIS system does not like to sit for more than 12 months (ideally even less). The entire fuel system will need to be gone through with a fine tooth comb. Here is the authoritative thread on that topic: 924Board.org :: View topic - 931 Resuscitation - how to resurrect a long-dead turbo
...and also a diagnostic approach that might come in handy if you do decide to pursue it: 924Board.org :: View topic - A Systematic Approach to 931 Diagnostics

Being a 1980, the car is referred to as a "Series 1". Some people automatically assume that the 1981-82 Series 2 cars are better, but not necessarily so...there are gotchas with both. For the Series 1, the original exhaust manifold (part # ending in 594) ALWAYS cracks under the #1 and #2 runners, impossible to see from the top with engine in situ, but a potential boost leak issue. Many S1s were converted to the S2 manifold (part # ending in 596), so if it has this manifold, that's a bonus. If not you're going to want to find an S2 manifold to swap on, because I can pretty much guarantee you the S1 mani will be cracked. Also, the S2 had an updated breather setup for the head, as well as an updated turbo oil drain. These upgrades may have been installed already on the car, again a bonus if so, and something you'll want to add if it's not already there.

The S2 cars had the infamous and finnicky DITC (digital ignition & timing control) which the above-linked threads discuss at length. DITC is great when it works, but it is terribly finnicky, and the crank reference sensor is unobtanium. As a consequence, some S2 owners have retrograded to the less sophisticated but more reliable hall effect setup from the S1 cars (I have one such example). Point being, from an ignition standpoint, the S1 will be easier (and cheaper) to resurrect.

The S1 has a funky ovoid-shaped charge tube and throttle body interface which is prone to leaking. Many S1 owners like to convert over to the S2 setup, which has a solid charge tube from the turbo to the TB, eliminating the funky rubber connector of the S1, including a single throat 60mm circular TB. This setup makes it much easier to adapt aftermarket components when adding an intercooler (for example).

The S1 also came with the G31 "snailshell" gearbox, while the later cars had the same Audi box that you are familiar with in the 924S/944 world. The G31 is infamous for having weak 1st and 2nd synchros. The shifting mechanism is also overly complex, and the rear shift linkage bushings are almost always shot, which only exacerbates the G31 shifting issues (see this thread: 924Board.org :: View topic - 1979 924 NA or 1980 924 Turbo shifting problems). Nevertheless, many people prefer the G31 gearbox due to its Getrag-style (a.k.a. dogleg) shift pattern. With practice, it is fairly easy to manipulate the gearbox without crunching 1st and 2nd, but it is not a fast-shifting box, and you shouldn't expect it to hold up in drag racing conditions. The biggest benefit of the G31 is that it is even stronger than the Audi boxes, which means it can handle tremendous power increases (which do lurk in the 931). More importantly, it came with an option for LSD, the same unit available in same-era 915s. I have two G31+LSD setups, and they are lovely. This car almost certainly has the G31; if you're lucky, it may also have the LSD.

The great news is that I can now provide a complete repair kit for the G31, including 1st, 2nd, and 3rd gear dogteeth, all of the synchros, and the complete seal kit. Most of the original G31 parts are unavailable, but through the help of a few 924board members, we've been able to identify replacement bits from other gearboxes, and I can source all of them in a kit.

Regarding the turbo, it is a Royal Pain to R&R. The big problem with them is the totally unique three bolt flange on the exhaust manifold-to-turbine housing interface. This means that without major engineering and expense, your only option for the turbo is the original K26 with its unique hotside housing, so you can forget about swapping in any type of modern T-style arrangement. Worse, the 931s turbine housing almost always cracks, and often when it does, it damages the turbine wheel. Even if the turbo spins, there is a high likelihood that you have damaged turbine wheel. Over 50% of the dozens I have personally inspected and taken apart were unusable, including the turbine housing itself. I have never, ever seen an uncracked turbine housing...so it's simply a matter of whether or not you can find one that is serviceable even if cracked. Good news is that John Walzel @ Majestic Turbo is very familiar with these units, and offers excellent pricing on rebuilds (~$350 assuming no major damage).

There are a whole bunch of other minor details of things to look for that can give you an indication of how well the car was cared for. If you'd like more info, feel free to send me a PM, and I'll give you some more stuff to watch for.
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Old 02-08-2010, 07:34 AM
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I am sure Rasta Monsta is still celebrating the Saints win and thus no comment.

Here is a link to the 931 forum and may answer many questions.
924Board.org :: View Forum - 931 Discussion
Old 02-08-2010, 07:38 AM
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Do not buy a 931 thinking it will appreciate. And even if by some miracle it did, you're still gonna be out a bunch of money on maintenance and restoration that would easily eclipse any increase in value.

Having said that, the 931 is a great car when its running well. With standard boost levels it exceeds the 944s performance and with a minor mod can be upped to Euro boost levels with the commensurate increase in performance. At the next level up you can add an intercooler and run 924 Carrera GT boost levels and you will see performance comparable to a 951.

All in all, great cars with excellent performance when maintained and in good condition but... and this is a big butt... absolute nightmares in bad condition and not running.
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Old 02-08-2010, 08:04 AM
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Timmcgraw67- You got to be kidding rigth your Fiero is 6 years younger nice interior ect ect & can't see an 80 -931 with only 50k if so it's your answer been sitting there because something was wrong with it & not running. Got nothing against the 931 a buddy of mine got one but it took him quite a while before he could sorte it out & the guy can tackle almost any thing mechanical, like somebody was saying you got to be a special person to own one,so maybe you should step back & think about it before making such a move.
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Old 02-08-2010, 09:19 AM
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exactly what I am doing right now ernie... taking a step back and looking at what I am doing. The story behind the car is it was bought in 85 at a car dealership in Nebraska with 20K miles driven til parked with 50K and replaced fuel pump 2 years ago and accumulator drove for a week water pump went out, replaced water pump last year, now fuel pump out. still with 50K miles. I am just wondering if these 931s will ever appreciate. I know that the fieros in nice oondition are holding their value and appreciating in some circumstances. Mine falls into the uber nice condition category. I just saw one sell for $4500 on ebay last week, will the 931 be there? I think that this car will clean up alright the right fender has a crinkle, the paint is faded (may be buffable), the dash is cracked it is light blue with green carpet and black (vinyl with grey suede inserts), the carpet is faded but may be able to bring back with flexible acrylic paint. All in all it looks restorable. I think the rear hatch is leaking as well as the sunroof. What I do see is it has the 5 lug and 16" dish rims, I assume it has the m471, I didn't see if it had the Koni shocks but even then I bet they probably have been replaced by now. It is a 5 spd dog leg. As I have red it had the desireable aluminum cradle for quick repair. How much is a car like this worth in tip top condition? Or is this more of a high maintainance toy for a person?
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Old 02-08-2010, 11:17 AM
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Why not keep the Fiero and purchase the 931.. Can't be more than $1000 for the 931.
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Old 02-08-2010, 11:57 AM
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Good point, flosho. If it's non-running, you shouldn't pay more than that, and probably a lot less.

Being a 1980 with the M471, it's highly likely that it's the so-called 924 Turbo "S" model, and if so, it may have an LSD-equipped G31...
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Old 02-08-2010, 12:07 PM
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Honestly I am seeing several good 951s in the sub 5k range.... If it was me I'd dump the fiero if you can really get 4500 for it and get a 951.... Thats about 1,000x more car....
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Old 02-08-2010, 12:41 PM
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951 will also be 1000x the maintenance cost of a 931.
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81 931
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Old 02-08-2010, 03:03 PM
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I highly doubt that.... A 931 is much harder to find parts for...
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Old 02-08-2010, 04:06 PM
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Quote:
Originally Posted by porsche4life View Post
I highly doubt that.... A 931 is much harder to find parts for...
Not if you know where to look => Ideola's Garage: Products & Parts for Transaxle Porsches

Just about the only part I can't currently get for the 931 is replacement lifter adjusting screws, and I'm working with ARP to develop replacements. And those aren't 931 specific in any event.
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Old 02-08-2010, 04:27 PM
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Timing belt Job = 2 hrs and $50.
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81 931
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Old 02-08-2010, 05:51 PM
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Call Me Stupid... Trade 86 Fiero GT for 80 931

OK...your stupid.

No seriously, don't do it.
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Old 02-08-2010, 09:57 PM
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A 5 speed in an 86 GT ?...must be a different transaxle, since the 5 speed getrag transmission was not added until 87.

I had an 87 fast back GT...ended up with 300,000+ kms and 2 clutches later.

Fun car. Very rare to see them on the road.

I'd keep her, and then buy the 931 too.
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Old 02-09-2010, 07:42 AM
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Man, what is with all the 924/931 hate around this place recently?!?

Sounds like a nice upgrade to me. I've raced against Fear-Os, and my crew chief used to have what was considered a nice one. They're still crap, either way - a shining example of corporate parts bin raiding by GM. And I even know some of the engineers that worked on them.

The 931, long-term, will indeed be worth more than the Fiero, IMO, due to rarity. I agree w/ flosho, though - why not keep the Fiero, and buy the 931 outright?
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Old 02-09-2010, 09:32 AM
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Agree with many that posted. I think the ring & pinion is different from the 911 type 915 transmission, but there may be parts to swap & get different rations between gears. Its steep going from 4th to 5th in the 944 type trans the later models use.

I'm one of those that changed the ingnition from late to early. When the Siemens box under the dash messed up, put an MSD box & early 931 distributor in wife's car. Siemens box is NLA.

On a hot day, like we have in SE, a 944, probably even a Kia, will kick even late 931 ass, 931 no intercooler. Cool tem, it's a different story. When it's right passengers say "Damn is this a 4 cyl?"

Fuel distributors, potential for more power, but they are high dollar & scarce. Late & ealrly are different along with WUR. Saw a Carrera GTS at Robleing. Had 8 cyl fuel distributor, could adjust boost to 1.5 from 931 stock of around .5 bar. Also had intercooler.

931s are good cars if you're hooked on them.
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Old 02-09-2010, 10:14 AM
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There you guys eat your heart out the most beautiful Porsche ever made & don't anybody argue with me there is no argument to be made.

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83-944 show room -sold___New ride 93-968 with SC steering wheel-ROW signal ligths- Susp M030 mods lowered,Porsche VA springs- Adjustable struts - Bilstein inserts - Bilstein sport rear -LSD -riding on Cup 1 wheels 17x8 frt 17x9.5 rear road contact Falken 452/ 225-45 ZR Front 255-40 ZR Rear -- Motor Mods /chip /K&N / mod air boxe just love the handling & power
Old 02-09-2010, 11:04 AM
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