Wanted: Best 911 Engine Combinations...

[Wayne 962]

Ok, I'm querying a whole bunch of people on this topic, trying to come up with a recommended list of engine combinations. Here is the intro to this particular section in the book:

Wayne’s Top Engine Picks

Okay, you’ve read this section, and you’re all excited about rebuilding your 911 engine, and extracting some more performance out of it. However, you’re still confused as to exactly what you need to do to get the engine performance that you want. In this sub-section, I have polled quite a few Porsche engine rebuilding experts, and have generated the following table of engine recommendations, based upon the performance characteristics you may wish to extract out of your 911 engine.

Keep in mind that these recommendations only represent a small sub-set of what you can do. With a custom crank regrind, custom-designed JE pistons, and even a custom-programmed engine management system, there really is no limit to the number of variations that you can achieve.

-------------------

Okay, what does everyone here recommend based upon their own experiences?

-Wayne

[tobluforu]

I've only rebuilt 1 porsche engine, so not sure if this counts but here goes. Started with 72, 2.4T motor. Installed rs pistons and kept the T cams as stated by Anderson. Great torque, but wasn't satisfied. Took cams out and had them ground at what was at the time called a slalom grind-whatever that meant. Even more torque w\ more mid range. Still not satisfied, so I put in E cams and am very satisfied with the over all power band. Had pump rebuilt by pacific fuel inj. Installed stock head studs which after 40,000 miles are still going strong. Plus did all the goodies that one is suposed to do.
That's it. Still runs great and that's after very hard driving
Can't wait to hear all the reply's by the TRUE engine builders.

[RarlyL8]

930:

K27-7200 Turbo
1 bar wastegate spring
SC or 964 Cams
C2T sized Intercooler
Aftermarket Heat Exchangers or Euro Exhaust

This is a 100 horsepower upgrade that is commonly done.

[Bill Verburg]

93 up 964 or 993 in a 89 or earlier chassis, B&B headers

[Wayne 962]

Sorry, engine swaps don't count...



-Wayne

[Bill Verburg]

Darn!!

[orbmedia]

I would say the tried and true:

2.7
Euro RS pistons/cylinders
S cams
light flywheel
Webers or MFI

When this comes on cam there is no other sound or experience like it.

[zuffenhausen]

A short-stroke 3.2 (98mm bore x 70.4mm stroke) with GE80 cams, headers, and a set of Weber (or even better, PMO) 46IDAs makes a very strong engine that loves to rev. It's probably my favorite 911 engine of all I've driven, and it's built from a common SC. It's also a tried-and-true combination so you don't have to worry about piston-valve interference (though it's still a good idea to check that when you build it). The idle is lopey but insane people like me could tolerate it on the street. And talk about useful track power when combined with a short ratio 915... pulls like a freight train from 6000-8000 RPM and wants to keep going! Ah, I miss that motor. Now we've taken it apart a built a scary 3.4 with it and I must admit I'm a little timid about pushing this new one, though I imagine I'll gain confidence with it once I get a chance to run it on track. Sure sounds mean though.

Oh, by the way, the 3.2 short stroke combination above dyno'ed at 305 crank HP on race gas, single plug. You'd probably want to twin plug it and be conservative with timing to run it on pump gas.


zuff

[emcon5]

Originally posted by zuffenhausen
the 3.2 short stroke combination above dyno'ed at 305 crank HP on race gas, single plug.

Holy crap. What compression ratio on that thing?

Tom

[zuffenhausen]

Originally posted by emcon5


Holy crap. What compression ratio on that thing?

Tom

Well, I didn't build the engine (Jerry Woods did, actually) so I don't know with 100% certainty, but it had the Mahle 98mm piston/cylinder sets commonly used for the short-stroke 3.2 conversions and I think those are 10.3:1. In Bruce's book he talks about a Max Moritz piston/cylinder set for that conversion, but everybody I've asked about that says "What's a Max Moritz?" LOL!

zuff

[82SC]

tell me more about your engine...I am planning something like that...did you switch the crank to a 3.2L 74.4?

I have been thinking of a long stroke 98mm or 100mm....

[zuffenhausen]

Originally posted by 82SC
tell me more about your engine...I am planning something like that...did you switch the crank to a 3.2L 74.4?

I have been thinking of a long stroke 98mm or 100mm....

Well, the 3.4 is not a combination I can recommend for this thread--at least not yet, so perhaps we should take the discussion elsewhere. I'll be glad to tell you whatever you want to know. Email me at zuffenhausen @ mindspring.com and I'll reply with details.

Regards,
zuff

[Wayne 962]

You can post details here, I'm curious...

-Wayne

[Wayne 962]

It's my recommendation that anything over about 9.8:1 should be twin-plugged. You'll be able to run it better on pump gas, and you won't blow it up from detonation. That sounds like a good engine, but it does sound like it's missing the twin plug...

-Wayne

[911_Dude]

Ive modifide my first and only P car and love it after driving it stock for about a year.
75S with a 2.7. I did as much as I could afford from B.A.'s book:
Webers, polished ports, Solex cams, and headers. This required eyebrowing the pistons. And then the standard "no gain- must do's", time certs, raceware studs, oil fed tensioners, 11 blade fan, electronic points. This gives a great midrange punch, and sounds so cool when its opened up. Im still going with the stock muffler. Ive been reading all the posts I can on muffler choices and nothing seems like its what Im looking for yet.

[pwd72s]

Originally posted by Wayne at Pelican Parts
It's my recommendation that anything over about 9.8:1 should be twin-plugged. You'll be able to run it better on pump gas, and you won't blow it up from detonation. That sounds like a good engine, but it does sound like it's missing the twin plug...

-Wayne

Which brings another question to mind...how high in compression ratio can you go? Single plug, pump gas? Well, what they call gas these days. Do the more modern ignition systems allow one to run higher compression than what was considered safe in the good old days? And...Oh...I think I just figured out WHY Wayne feels there is a market for such a book...

[zuffenhausen]

Originally posted by Wayne at Pelican Parts
It's my recommendation that anything over about 9.8:1 should be twin-plugged. You'll be able to run it better on pump gas, and you won't blow it up from detonation. That sounds like a good engine, but it does sound like it's missing the twin plug...

-Wayne

I agree completely. For us, this was a race engine only, so the single plug was fine 'cause we were running race fuel. However, I can't think of anything about the engine other than the lack of a second plug per cylinder that would prevent it from being a killer street/track engine too. Like I said, the idle and low end torque are somewhat lacking, but a lot of us are crazy enough to put up with it.

As for the new 3.4 my father and I built, it came to be as a result of a 915 gearbox breaking under full load at Summit Point Raceway in WV. When the gearbox went, the 3.2 was zinged as well and all the valves were bent. Up until that time, the 3.2 had been a powerful and bulletproof engine for several seasons. The car races in PCA's GT-3S class for which the displacement limit for a naturally aspirated engine is 3.4 liters. So since we had to take the engine apart to fix it anyway, we decided to build a more powerful 3.4 liter engine.

The new engine uses a 74.4mm Carrera crank, Pauter rods, and JE pistons which retain the 98mm bore. The compression ratio is 12:1. We had the heads repaired and twin-plugged. We're still running the GE80 cam which should work well, but a GE100 would probably be a better match for the larger displacement. This is a race engine only, thus my hesitation in including it in this thread, though I'm glad y'all are interested as I am very excited about it.

As for building a 3.4 street engine the same way, by substituting a 74.4mm crank and using Mahle 98mm pistons & cylinders, I'm sure it would make a nice street engine as well. It's just that the short-stroke 3.2 is much cheaper to build (the 74.4 Carrera crank alone cost us over $1500) and really likes high RPMs. I imagine when we'll eventually spin this new 3.4 to 8000 RPM too, but I'm just honestly not as confident in the Carrera crank as I am in the SC crank. The short-stroke 3.2 is just a great combination.

Oh, one more thing about doing a 3.4: there are distributor issues to consider when you change to the Carrera crank. You either need to swap drive gears before you put the crank in, or you need to get a clockwise distributor. My father and I found that out the hard way when we tried to put the distributor in the new 3.4. Yup, we had to tear it back down all the way to the crank, change the drive gear, and build it all over again. We had already spent the $$$ on the twin-plug distributor, so redoing the engine was the best solution. There was a lot of profanity when we figured out why the distributor didn't fit. I never have figured out why Porsche decided to change the way the distributors run on the SCs.

Regards,
zuff

[RLJ]

Motor:
1983 SC 3.0 95mm x 70.4mm
Bored and sleaved cylinders to 98mm 3.2 liter
10.2:1 J-E pistons
Web-Cam #120-104 grind
3.2 Carrera heads, upgraded springs/retainers,dual plugged
PMO 46mm carbs w/ tall manifolds
Dual plug 964 distributor conversion to mechanical advance
ARP rod bolts
Carrera pressure fed chain tensioners
twin MSD 6AL ignition boxes
930 lower valve covers
Elverude aluminum flywheel
Sach aluminum pressure plate
SSI heat exchangers
S-CAR-GO Racing dual in/out stainless steel muffler
281 HP-244ft/lbs torque @ 6700 RPM on PUMP GAS

Gear box: 1983 SC 915
ZF LSD
Factory short shift kit
8:31 R&P
1st gear / 11:35 ( stock )
2nd gear / 17:34 ( down three ratios )
3rd gear / 21:29 ( down two ratios )
4th gear / 25:26 ( down one ratio )
5th gear / 38:30 ( stock )

I have bought throttle bodies and in the near future will add EFI.



Randy Jones
1971 911

BTW- This is just one guys idea not saying it is correct for anyone but ME.

[WydRyd]

OK, MY dream engine, here it goes:

Start with a 3.2 Carrera Engine platform and add:

RUF 3.4L Turbo P&C's (7.5:1)
RUF Lightweight Titanium Rods
ARP Rod bolts & head studs
964 Piston Squirters
964 Oil Pump
Twin Plugged heads
Extrude honed intake manifold & ports
GT2-Evo CAMs
Flame ringed cylinders/heads with Aluminium sealing ring
944t Injectors
Motec/Autronic Injection (Pressure Sensing)
Twin T3/T4 Hybrid turbochargers
Twin TiAL 40mm Wastegates
Dual in/out free flowing muffler
Electronic Boost controller set to max of 1.4bar
Custom 900+ Cubic Inch Intercooler

Hmmmm - should be good for 600+ HP

[Wayne 962]

Hmm, indeed these are very cool setups, but they would probably be very difficult to drive on the street.

Anyone with a driveable car (that's not crazy?)

-Wayne