Anyone using a 915 in a 3.0 litre turbo 930

[obrut]

915's don't seem to be recommended for the 3.3 turbos, but what about the 3.0's?

A stock 3.0 makes about 260hp which is about the same as a hot na 3.2 or a stock na 3.6 - both of which seem to be fine with a 915 if not driven carelessly.

Anyone have any first hand experience of this combo? I'm looking at a car for sale with setup.

[tailwind22]

A very good race mechanic down in Florida told me that you would not want to push much more than 300 hp with a 915 unless you were willing to drive it very passive. Thoughts?

[drmatera]

I think torque is the issue. Turbo motors make a lot more torque than N/A motor

[proffighter]

Good idea to disassemble the tranny very quick. For even faster results, just increase boost to... let's say 1.5bar

[quattrorunner]

I wish I had a 930 box.
I have a 3.0 930 engine and I don't have issues yet, but I would raise the boost if I had a 930 box. That said, I have become pleasantly comfortable knowing that my 915 with 8.31 ring and pinion is a great fit ratio wise for really good performance. But there is a limit and I'm up against that limit torque wise. If you keep boost at stock with around 265 hp that would still have higher torque than the cars this transission was designed for. But I'm over 325lb ft torque and have a year under my belt with no grenades as of yet.
If you have a 930, I would just rebuild it.

[obrut]

Thanks guys.

[timc]

Correct me if I a wrong, but I believe "Rarlyl8" ran a 915 in his 911SC (The Red Rocket) that was converted to 930 body and suspension with a 3.3 approaching 400HP????? I really think it's about how you drive, and when you lay down the power....

Edit: Disclaimer - I don't think I would call this the norm, and there was a reason Porsche went from the 915 5sp to the 930 4sp with stronger internals. But I think if you are careful it can be done.

[DGW]

I have one. My Porsche wrench thinks its a great combo, just don't boost it in first gear. I have unintentionally done that (not often), and its still together.
He had a 3.0 years ago that he put a 915 in, it makes the car a lot easier to drive on the street.

[sjf911]

My 915 had a loose pinion bearing race from just the stock motor. After turboing it, it had a very loose front main shaft race so I don't think it will hold up too long. I did put in a single piece bearing retainer and heavy duty side plate as well as have WEVO fix the main case and CMS the final development housing. Despite this, I figure I will need at least one replacement tranny in my future ownership. Still cheaper than a 930 or G50 upgrade.

[Uncle]

Are we talking wheel H.P or Flywheel H.P here?
I ask as I thought the 915 going bang mark was ~350 to 400 wheel H.P. I was aiming for my 3ltr & 915 build to be ~300RWHP with boost in 1st grear limited to almost nil just to be on the safe side.

[obrut]

I was talking fywheel hp.

From memory, a stock 3.0 made about 260 and a stock 3.3 about 300. But its the torque that busts things.

My former 3.3 (Kremer modded) 930 made 370 flywheel on low boost - truly silly acceleration...

[Uncle]

I'd better start looking for a 930 4 speed then lol.

[spence88mph]

Brian RareyL8 ran 915s on his previous 350-400hp 930 and swore by them, I think he broke at least one in the process though.

[dean]

I put a stock ROW 3.0L 930 in my SC with the stock 915 tranny. It felt like the tranny was going to blow up if I floored it in first gear. It is no fun having a nice car that you can't drive the way you want to. So I put a G50 in it. I have never looked back.

[spence88mph]

Something else to remember is Rex Broadbent's car uses a 915 and he has 350ish hp from an NA 3.4. He doesn't go lightly on that car, they must be able to work.

[quattrorunner]

Originally Posted by spence88mph

Something else to remember is Rex Broadbent's car uses a 915 and he has 350ish hp from an NA 3.4. He doesn't go lightly on that car, they must be able to work.

It's the torque not hp numbers that hurt.

[spence88mph]

What I'm saying is his engine would have a lot higher hp and tq numbers than any stock 3.0T and he makes it work.

[spuggy]

I just took a 915 out of a car making 370 HP and 350 ft/lbs - at the wheels - in favour of a G50. It was in there for quite a long time (6 years); they don't necessarily grenade if the 915 is treated with some basic respect and common sense (don't just yomp on the loud pedal at 2000 RPM, no drag starts etc).

But that 915/72 got built up (LSD, oil pump cover, spray bar kit, WEVO bearing retainer) to replace the '77 915 that a stock(ish) 3.3 chewed up and spat out (before my ownership, so I actually have no idea what kind of shape the original box was in before the turbo blued the 5th gearset and turned the cases to soap around the bearings).

There's an old thread on this on the 911 forum http://forums.pelicanparts.com/porsche-911-technical-forum/250779-how-beef-up-915-thread-parts-costs.html

I'm pretty sure that when Hayden says "350 ft/lbs" he means at the flywheel - like the factory would. It's only the turbo guys that quote at the wheels.

[Matt Monson]

You guys are taking about the torque of the turbo, but how many guys have done 3.6l swaps into 915 cars? They can take plenty of torque as long as you tend to reserve it for 2nd gear and up.

And you should be sure the 915 is healthy to start with. A tired 915 does not suffer much added power for long.

[RarlyL8]

I ran the 915 we were discussing in the link above for several years after building it up with WEVO parts. We then built an '86 Euro 915 with factory oil cooler when my headers went on. That engine (360ft/lb torque at the wheels) with tranny ran for a few years and was sold with the car about a year ago. The built 915 is a blast as long as you know the limitations and respect them. I now have a 930 tranny and do not like it with the stock 300CHP engine. Once the engine is 400WHP the 930 4spd will work better.