2.7 & 901 vs. 3.2 & 915

drystack · 10-09-2007, 08:56 AM

Is a 2.7 with Webers, etc. making ~230hp powering a short-geared 901 with LSD going to feel much different than a chipped 3.2 making a little more power running a non-LSD 915? Apples to oranges, but both cars are 73s and weigh about 2250lbs. I'm concerned that the 2.7/901 may feel like shifting a dumptruck in comparison and be close to its max power capacity. Any thoughts?

Steve@Rennsport · 10-09-2007, 10:22 AM

Hi:

Some clarifications are needed,......

Are you asking about shift qualities between the two transmissions?

Are you asking about the personalities of the two engines?

Are you asking about the durability of each transmission coupled with the respective engines?

There are major handling differences between an LSD-equipped car and one without; are you aware of what that really means?

The answers to the above really decides how to help you.

drystack · 10-09-2007, 11:32 AM

Yeah, kind of vague, sorry

Mostly concerned with the shift quality and drivability. I'm not able to drive the 2.7, nor have I ever been in one to compare to the 3.2. Will a short-geared 901 mask the torque loss of the 2.7? I am familiar with the LSD performances in a traditional live axle setup and feel that for a driver it is not mandatory, but for a more performance oriented car it is.

And finally, will a 901 withstand 225-250 hp for long?

Thank you
Matt

twin plugged targa · twin plugged targa's Garage

I may be corrected here but I believe the 901 will handle up to around 250HP fine.
I believe my 2.7 (with 901) puts out anywhere from 220-230HP and feels much faster than my old 86 Cab. which had about 209HP and a 915 non LSD.
My 2.7 targa is the quickest feeling 911 I have driven, it actually felt much faster than Rattlesnaks RSR with a 3.6 and 915 - but believe that had longer legs.
A 2.7 with carbs sounds so much nicer than a 3.2 injected if that helps any!.
Rgds Ben

RWebb · RWebb's Garage

fine??

Todd Simpson · 10-09-2007, 01:30 PM

If the 2.7 was built well it will be much more fun than the 3.2. It'll rev faster, sound better and redline higher (depending on cams). The 901 shift effort is lower than the 915 but the shifter sloppier.

The 3.2 will start easier and get better mileage while being dull in comparison. (I have a nicely worked euro 3.2, 964 cams, early exhaust, etc. and I think it's dull compared to the early engines)

The 3.2 will leak less oil, last longer and you'll never need to tinker with it.

drystack · 10-10-2007, 06:26 AM

So with all the gloom and doom regarding the 2.7 motor and its head studs, overheating, what exactly needs to be looked for that will minimize these concerns?

Thanks again

Matt

Kemo · 10-10-2007, 06:38 AM

ive seen a few threads posted here on the site. i bet a good search would bring up some info.

in a nutshell, if you have the head studs replaced and install case inserts to stop the studs from pulling, you have done a great service to the longetivity of the engine. Aside from that, dump the thermal reactors if you have them and get a big assed oil cooler. Then go drive the hell out of it

Steve@Rennsport · 10-10-2007, 08:43 AM

Quote:

Originally Posted by drystack

So with all the gloom and doom regarding the 2.7 motor and its head studs, overheating, what exactly needs to be looked for that will minimize these concerns?

Thanks again

Matt

IMHO, the "gloom & doom" about the 2.7's has been wildly exaggerated. These are excellent engines IF,............IF they are built properly; these do not suffer fools who take shortcuts in this process.

The only issues with the 2.7's is the need for some extra case preparation which is not always cheap to do and the requirement for an excellent oil cooler system to maintain oil temps in the 180-190 deg F range.

Properly prepared and assembled, these last as long as any 911 engine.

RWebb · RWebb's Garage

search on line bore & align bore -- iif the 2.7L needs that work, it is not cheap and needs to be done by a good machinist with experience with the 2.7 not just any machinist; but it may not need it.

Todd's comments relate to the cams, induction & exhaust -- the option not mentioned is to modify a 3L or 3.2L motor with Webers - it will rev as well as a 2.7

the 2.7L is more period correct...

RWebb · RWebb's Garage

some info on transmissions - note it is not hp, per se, that is the concern - also, you really need to watch 1st gear on the 901/911