I'm keen to learn more about boosting a 3.2 using a modern turbo with no lag - is your build documented somewhere? How much HP can a stock 915 tranny take?

Precisions spool insanely quick!

My turbo lags, but it's capable of 830 hp. Put it this way, I can put the original entire K26 turbo (the 930 turbo) inside of my turbine housing. Turbine housing, AR, and turbine wheel size account for the lag or lack thereof.

Ok, that is a stretch, but you get the point. My modern Borg Warner S366 spools quicker than the ancient 60-1 HiFi turbo I had before that maxed at about 500-550hp.

They've come a long way.

Anyhow, read this thread (Protomotives Todd Knighton did a lot of 3.2 stuff back in the day):

http://forums.pelicanparts.com/porsche-911-technical-forum/56563-protomotive-turbo-kit-information-what-do-you-think.html

BTW, the 915 will handle 350hp safely from what I read here, but at 400, good bye!

So at .5 bar, what is the effective compression ratio? Or is that the wrong way to look at it?

love love love PT units. Reasonable too.


I might FI my 3.2

Stock 3.2 compression and .5 bar of boost is ok.

Not sure ECR?

Lots of great, cheap kits out there now to FI your engine.

going to 3.6l but using the existing 3.2 case is done over here. The common opinion is that while 3.4l is a plug and play solution and good if you have to rebuild the engine anyway, it will not result in dramatic power increases. Machining the 3.2 case and using 3.6l P/C with a 964 crank is expensive but apparently a good way to make a lot of power.

Maybe if you putt around, butt remember that Brandon grenaded two 915s and I believe that he is likely a little bit under 350hp. :)

Having a 3.2 with ITBs I agree with this.
In a nice and light 69 tub this will make a sweet engine!

*Awesome throttle response
*Incredible sound
*The right "look".

The added power might not be that big (my ROW 3.2 dynoed to 265 with headers, stock otherwice), but the character of the engine is transformed.

With the aftermarket EFI, that is necessary, you could also go twinpluged or stay single with coil-on-plug without the expensive distributor.
.

Been to their website, which set up mates with the 3.2?

looks to be this one - Throttle Body Kits : Porsche 2 bolt large port. SF Taper throttle body kit - Jenvey Dynamics

These 2 motors are great upgrades and look stock, they retain the entire stock DME and harnesses while bringing the EFI a bit more modern:

Twin Plug 3.4L upgrade:
http://forums.pelicanparts.com/911-engine-rebuilding-forum/871561-1985-3-4-build-using-maf-279-56-hp-237-63-rwhp.html

Single plug 3.4L upgrade:
http://forums.pelicanparts.com/porsche-911-technical-forum/851912-my-87-3-4-maf-project.html

Both those setups are rock solid every day drivers.

3.8 from a 3.2
 

Hello
I'd like to share with you my experience between stock 3.6, 3.6-to-3.8, and 3.2-to-3.7 engines.
I have all of these engines currently in my cars. Patrick Motorsports built the RS spec 3.8 from a 964 3.6. They also rebuilt the 993 3.6, and the 3.2-to-3.7 is an engine built by Bill Rudtner that came with a car I bought from Michael Serrone.
To be blunt, the best overall engine, with the most usable torque, power delivery, rawness and monster power is the Rudtner-built 3.7 from a 3.2. It is simply awesome!
The 3.6 and the 3.6-based 3.8 are great but lack the low end of the Rudtner engine, the specs are:

Based on a 3.2 case – boat tailed
3.2 74.4mm crank stroked to 76.4mm Re-nitrate
Using 2” rod journals utilizing NASCAR type rod bearings.
Center drill for better oiling to #2 and #5 rods (special center main bearing) engine able to turn to 8600 rpms, but I am holding it down to 7200 rpms.

Custom Pauter Connecting Rods – using Raceware Hardware
Camgrinder -DC62 profile on a 108° lobe center
Race Springs, Ti Retainers

3.2 Heads – Dual Plugged & Ported

102mm LN Nickies 11.3 to 1 CR

JE Pistons coated

50mm PMO Carbs

Smart Racing Oil Filter Console

1¾” Nabel’s Headers into a custom 2-into-2 banana muffler with interior x-pipe and dual 80mm outlets

Spark controlled by dual MSD

Patrick Motorsports Twin Plug dizzy

Light weight flywheel and HD clutch

When I first bought this engine it came with 52mm ITBs, Haltech management sys and accel coil packs but decided on carburetors and it made it even better.

I am so happy with this engine, that my plans are to replicate it for my other cars and sell the 3.6 and 3.8 engines.
Thats how much difference I see and my highest recommendation for ending up with a 3.7. Build it out of your 3.2.
Cheers
MD

yea but you didn't say if the 3.6 or 3.8 had anything but stock induction plenum, the more stock 3.6 should be more reliable in the long run and would make more with the 50's also:)

I went 3.4. I thought about 3.6.

Costs depend on what you do. A 3.4/3.5 is a great idea in my mind if you need to rebuild your 3.2 anyway. The 3.4 can be had cheaper especially if you go for max mortiz pistons that retain the single plug setup. Plus, after the rebuild, you know exactly what you have.

A 3.6 will be more reliable, and more drivable than a hot 3.4/3.5 (depends how hot). However, the savings are only there if the 3.6 does not need a rebuild. 3.6 engine prices are rising fast. I guess the trick is getting a good one. Downside on costs it that flat torque curve. It will shorten the life of the gearbox. More of an issue with 915's... But our local 3.6's like to chomp on oem gears. Not cheap. Upgrade your gears to something from guard transmission if you go this way.

I needed a rebuild anyway, so went 3.4. Had i not needed a rebuild, and had access to a good 3.6, i would have gone 3.6. In reality, the cheapest option of all is to buy a good 3.6 car that is completed. I tried to do that and still think of the money i would have save had i persisted.

Reliability
 

You are right that I was not specific about the induction of the other engines, I'm sorry for that. Here are the induction specs:

-One is a stock Vram 3.6 and motronic
-One is a 964-based 3.8 RS spec with Vram induction and motronic
-One is a 993-based 3.8 RS Spec with 50mm PMO carbs
-One is a 3.2-based 3.7 with 50mm PMO carbs

The one I prefer as mentioned is the 3.7

No one can say with absolute certainty that one rebuilt engine will be more reliable than another, once you rebuild even if specs are stock, there are too many variables to be absolutely certain.
None of these engines are eternal, I would hope to be able to squeeze 100k miles before rebuilding again on any of them.
My criteria on which I prefer is based mostly on the most enjoyable, fun, fast and exiting engine to drive. I would prefer to have this even if it came at the cost of shorter engine life. I know it is a very personal opinion, but all I want is to give the original poster a personal insight on direct comparison of these engines based purely on enjoyment, after all, isn't it that the very reason for spending on these cars? Pure driving bliss until we can't drive anymore.
We (users) also have a limited mileage and I'd rather spend my last days having fun than choosing reliability for the next owner.
Just a thought
Cheers
MD

No use saving your girlfried for the next guy to use. Have fun with her while you can!

But some engines can be like a porn star with a cocaine habit. Fun i am sure, but count the relationship in hours and get out your wallett.

More than likely, in the 3.2 to 3.7 case I think your cam choice is what makes that motor behave as it does. Those DC62 cams on a 108 lobe center is what results in that engines torque profile.

Oh snap........pun intended, butt of course. :)