Contemplating an 85 Cabrio purchase have a few questions

[dman525]

1. 915/vs g50 trans. I hear a lot about how much better the newer trans is. Will the 915 last as long behind the 3.2 motor?

2. Horsepower. Was it just a DME chip change that gave the later 3.2 cars more power?

3. Early Motronic issues. Are there any problems with the early adoption of Bosch Motronic on the 3.2 motors that caused issues?

4. Anything special to look at on an 85 Cabrio from a problems/issues perspective ?

Thanks

Derek.-

[Macroni]

Derek,

I have a 915 mated to a 3.2 in my longhood. I had a g50 in my Cab. The difference to me is the concentration to hit the proper gear; 4th to 5th. A bit looser but I drove another car w/ a very tight 915. Otherwise no real difference noted.

All my issues w/ the cab were related to the top. Went throught a motor also had issues w/ the relay. Dry rot took out the liner and the fabric covers on the window seals. The top cover stiching were wearing when I sold the car.

Lots of great low mileage cabs out there. Good luck w/ your purchase.

Luke

[84_Carrera]

Derek,
I have a chipped '84. As I understand it, the DME boxes went from 24-pin / 2k memory to 28-pin / 8k memory over the years. Tuning on the DME was better as you got closer to '88/89. It's also my understanding outside of Euro cars with higher compression, the US-spec 3.2L are the same through the 84-89 range. Someone feel free to correct me on that, though.

I have been told by Steve Wong that converting my early DME to a later memory / pin style chip will yield better driveability (ie, less surging, etc.), but I'm not sure there's any peak numbers difference in the aftermarket chips.

FYI, I'm making around 213-214hp from memory at the wheels. I'm also running a crappy Weltmeister chip, has been in there for around 60k miles IIRC (I bought the car at 50k, clocked 92k this month & it was in there when I bought).

I just had my 915 rebuilt this year due to 1 & 2 synchro issues while the clutch was being replaced. The mech who did it build stuff for track use also, and told me a 915 is absolutely fine up to about 300, maybe 350hp tops; after that yes, the G50 is absolutely the trans you want on a modded setup. It's going to hold up fine with a normal / lightly modded street car.

The big thing about a 915 is the bushings, and the lack of a gate, really. Put a Wevo gate in the trans & I think any real likelihood of doing a high rpm 3-2 mis-shift is negated.

The only possible issue with my DME box MIGHT be tach signal related. I just swapped out the voltage regulator this week with a new one, and my flukey tach is still there. I've pulled the tach out & am sending the rebuilt unit back to North Hollywood Speedo this week & have them take another look at it. I have a signal at the tach lead, but intermittent working / intermittent misreading (low) on the unit, and I've been told one possibility is the DME unit itself (pricey).

Cab-specific, I'd look for alignment issues / chassis tweaking, especially if the car's been suspension-modded. I put the roll bar back in this week & noticed a nice increase in stability, and also that it was harder to reinstall this time. To me this indicates things are moving around a little too much for my liking after going to 22/29 t-bars & upping from Boges to Bilstein HD / sports.

Cab top, look for replacement or if original, make sure the zipper's intact, look for shrinkage, fitment / leaks. Mine's a manual top w/ manual seats. I have plenty of height for me (6'1") w/ helmet for occasional DE days.

Speakers will likely be toast w/ a cab, look for weather exposure, how dry are the seats, dash condition, etc. As for said speakers, I took the opportunity to replace the tiny 4" round speaks with some 6.5" Infinity Kappas, & they've been great. Get an under-seat sub if you like music, you'll lose any low-end with the soft-top. I have a Nakamichi deck, no amp, Kappas all around, and a Clarion powered sub under the pass. seat. Not too shabby for everyday tunes.

Keep in mind the rear seats actually angle forward with a cab to make room for the top. It's bad enough back there, but my 9 year old is starting to complain vs. when he was 5 or 6.

Other than that, the normal 3.2L Carrera look-fors apply.

Good luck.

[craigyirush]

My understanding is that the G50 cars had 217 bhp as opposed to 207 or thereabouts.
However, the G50 box is also heavier.
I would drive both before you make a decision - some prefer the vintage feel of the 915, others swear by the more modern gate of the G50.

[tonythetarga]

Originally Posted by craigyirush

My understanding is that the G50 cars had 217 bhp as opposed to 207 or thereabouts.
.

Correct about the HP numbers. The ratings are at the flywheel on stock engines. The Euro engines had a higher compression, therefore higher hp.
If 84-Carrera's car is making 214 at the wheels and the car originally came with 207 at the flywheel, then he is making horsepower from somewhere other than the chip, crappy or otherwise, you won't pick up 25 or 30 hp at the wheels from just that.
My car is a stock everything 86 except I have installed headers. The dyno at the wheel hp is 198hp, which puts it roughly equivalent to the Euro stock 'at the wheel' hp (231 at the flywheel).

A well serviced 915 is a good transmission, but as always, buy the car based on overall upkeep and value unless you specifically want a car with the G50 trans.

[84_Carrera]

Sorry, just checked, it's just under 213 at the wheels, sorry.



I have the airbox removed & a K&N Cone, Weltmeister chip, stock heat exchangers, Fabspeed pre-muffler & M&K 1-in / 1-out muffler as of the dyno, Magnecor wires, std Bosch plugs. This was right after a fresh cap & rotor from memory, after the trans rebuild & new clutch. Mech did a +6% fuel adjust setting change on the DME prior to the dyno run. 2 previous runs are also shown, 203 & change was as-purchased, stock airbox, stock cat & muffler from memory, and the other one I think was pre-muffler & another muffler, plugs near the end of their lifespan.

I am very pleased with the numbers, obviously.

[whiterabbit]

I have an 1984 cab and love it. I believe this year is lighter due to no power hood. The 915 has been rebuilt and shifts as well or better than a G50 I owned before. Mine is ROW with SSI's, M&K and a SW chip so I assume about 250hp at the flywheel, it seems plenty fast.

[dman525]

The car is stock. under 60K miles on it. Will have the local shop scope it out before I pull the trigger on it. My girlfriend in high school had a 911 turbo body cab - really enjoyed driving that car. Never spent enough time with it to learn the mechanicals. Being around BMW's for the last 10+ years, I have gotten to know the German hardware pretty well.

[84_Carrera]

She's a looker. Burgundy interior like mine? Good luck finding interior pieces to swap should you want them. To do again, I'd be looking for a black interior, easier cheaper to get stuff that matches.

[dman525]

Originally Posted by 84_Carrera

She's a looker. Burgundy interior like mine? Good luck finding interior pieces to swap should you want them. To do again, I'd be looking for a black interior, easier cheaper to get stuff that matches.

That Pic was of the girlfriends 911, and it had the lipstick red interior.

Car I am looking at is not a widebody and it has a black interior.

[450knotOffice]

She had a beautiful widebody Cab there.

[ChkbookMechanic]

Originally Posted by dman525

1. 915/vs g50 trans. I hear a lot about how much better the newer trans is. Will the 915 last as long behind the 3.2 motor?

The 915 transmission in my '84 appears to be original (at least from all the records I have) and still shifts fine. Of course you really have to have all the bushings and such in good shape.

2. Horsepower. Was it just a DME chip change that gave the later 3.2 cars more power?

Fom what I understand, each year Porsche got a little more aggressive in finding more power in the air / fuel maps.. which seems almost standard.. you always need to give cars that year to year hp bump..

3. Early Motronic issues. Are there any problems with the early adoption of Bosch Motronic on the 3.2 motors that caused issues?

I have the first year of the Motronic ECU and other than getting a tune up on the engine and getting the idle set correctly the ECU has been ticking right along with no issues.

4. Anything special to look at on an 85 Cabrio from a problems/issues perspective ?

Not familiar with cabrios, but I'm sure you should look for rust, leaking oil, etc. like you would all 911s. You can also check the fit of the top when it is up and if there are any tears in the soft top.

[porschenut]

The difference in stock hp shouldn't be a consideration, as you won't feel 10 hp.