Idiot needs help to hit build target
 

Have '85 3.2 that I'm going to rebuild (as soon as I can find space to work in.) Have experience rebuilding to stock but this time stock is off the menu (to some unknown degree.) It's typical to build for more HP, torque, etc.----not going there for this build. Instead, this build is dedicated to enhancing/optimizing engine's run-ability. Result should be an engine with emphasis on durability first---from this should come a measure of performance. My basic knowledge grasps reducing reciprocating/moving weights. Easing air flow in the case. Ultra balancing moving parts. But how? What more is there?

Time wise I can spend as long as it takes. In this regard, attention to detail is invited to go insanely overboard. Dollars... would like to think engine parts, machining, finishing services don't need more than $17k to reach the goal. (I have another $3k for suspension parts. Ultimately, these $s in combo are hunting a very fine street 3.2.) Outside-the-box thinking is welcomed. Am open to designing and machining new parts (keeping budget in focus... and so needing to avoid parts calling for professional/expensive engineering.) To some extent this is a creative platform to explore new ideas that focus on simplicity & functionality. Also to some extent, this is a sculptural endeavor so finished engine wants to have some unique, interesting appeal.

I know enough to be dangerous given where this project is heading---into the unknown for me. Am also smart enough to seek guidance from you who have genuinely been there and done that. Am looking to rough out a project plan so $ budget has some basis.

Help is requested... What to do? How? Materials? Resources? New ideas?

As far as rotating mass goes. A GT-3 crank has more counterweights, thus smoother, and it has a longer stroke for more torque. Carillo or Pawter rods, light weight and stronger. Titanium rods? Pistons are a debate for others with more knowledge. In my current motor I used JE pistons. They are forged, so stronger and lighter than stock, plus you can optimize your CR.

If it was me, I would go dual plug, with a 12 cylinder distributor. That is the ultimate bling IMO.

One would have to ask why go in this direction since stock Carrera motors are bullet proof and last for ever as is?

I have some trouble imagining how the 3.2 Carrera's street suspension could be improved for street use. I have always thought, when rattling around in my street/track car, how I had adversely affected the balance between handling and comfort that Porsche had built into the car.

The only thing I can think of for an engine rebuild for street purposes beyond the usual you'd do for any rebuild would be to use aftermarket high strength rod bolts. Not that the stock bolts are a significant weak spot for street RPMs, though, but why not. And convert the CHT to the two wire system. On my wife's 3.2, we had the voltage regulator go bad (and the brand new replacement did, too, and in a rather short time for a new part). So I'd be inclined to pay the Porsche premium and replace that, need it or not.

GT3 crank and Carillo and Pauter rods noted Gordon---appreciate you breakin the ice here. Looked into titanium… $6,700 as opposed to $1,700 (Pauter.) Hefty dollars for tits. Would you consider JE pistons better as in lighter and more durable than Mahle? Concerning CR, is there any better fuel-burn value to upping from 9.5:1 95 mm to 10:1 98 mm or is this a more power upgrade?

Your dual plug idea… was initially thinking that being complete heresy where this build is concerned but maybe not. If there’s a better burn AND this can be done with EFI… is interesting. If pure bling… we’re back to heresy! (Have feeling you’re lusting after 12plugging it!) Think I’ve seen somewhere in PPF that going to 10:1 CR requires 12plug to work well. ???

You ask “why go this route since 3.2s are bullet proof?” Agreed that 3.2’s reputation is robust.That said, this build’s direction believes this: it cannot be that any engine is “completed.” In other words, Porsche---given 'for-profit' economics---left us space to explore and improve on what they created. In this case making their engine more resilient, durable, sustainable, efficient, etc. Much of the “void” left by Porsche deals with time-given value IMHO. For example, if you or I will spend 10 hours doing what Porsche’s bean counters forced their production person to do in 1… I’ll say we’re very likely to improve on what Porsche’s production person can do. That’s not to be critical of Porsche or to brag on us. Am seeing this as a simple reality. After time-given value comes the opening of Pandora’s box of new technologies. EFI by example---surly something to explore for this project.



Good point on suspension Walt. I must say that suspension budget here is to maintain existing system---new bushings, struts, ball joints… that sorta stuff. Should also note that 3.2 in this case is in lowered ‘80 SC. Not sure if ‘80 is in same suspended performance territory as ‘85. My 911 is so slammed-down there’s little suspension travel to begin with. I looked at KW coil over systems. If, at the end of this engine build there’s surplus $’s… I’d consider KW parts if only to explore whether their apparent glitz offers any functional value (to a slammed 911.)

High strength rod bolts… a fine---subtle---idea. Brand?

CHT… why 2-wire? And does that include a sensor change? (Am azzuming CHT is Cylinder Head Temp.)

VR… engine has 4 year (approximately) old Bosch alt with internal VR. (Replaced that alt due to VR failure.) Perhaps extricating VR from alt has merit.


All input/ideas are going into a spreadsheet. Will consolidate everything and eventually share whole of it. (Distillation is likely in order to make budget work. Then on with build.)

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I realize we are bench racing, as it were, however, as far as dual plugs go, Porsche went to that on their 3,6s. Why? Probably for two reasons, emissions and efficiency. They allow a higher CR to run safely. It also aids in preventing pre-ignition.

In a perfect world Mahle would sell forged pistons for the 95 or 98mm cylinders. But they don't. I and many others are using JEs with not issues. They are forged and considerably lighter than the stock Carrera units. There may be better pistons out there, but what?

ARP has the rod bolts.

Something else to consider would be a 3,6 or GT-3 intake manifold. Then add ITBs to that. Take a look at what Singer does to their motors for some more inspiration.

Lets see what the gurus on this board have to say.

Trackrash -- believe Mahle does sell 98mm forged pistons, see, e.g. https://patrickmotorsports.com/products/eng-ps98-010 -- and, these are optimized for single plug applications.

One bulletproofing idea I'd push is going with Paulter rods -- folks consider the smaller rod bolts used on stock 3.2 pistons to be undersized and a weak link -- Paulter uses the same size (larger) rod bolts as a 3.0 rod . . . .

But you can't buy just the pistons, you have to buy the P&C set. Sorry, it is a sore point with me. Open a Jeg's or Edelbrock catalog and you can get Mahle FORGED pistons made for small block chevys, but not 911s.:rolleyes:

Those Mahle sets are a great option if you have worn out cylinders and want to go to 3,4. They won't work with an aggressive cam however.

It would be best just to talk on the phone, i know that doesn't have the benefit of every one seeing for all time and being able to pick apart BUT there is just to much to type on this subject. If you would like to talk on the phone i can quickly tell you what i know and also you can bounce ideas off me and ill tell you my real world exp. with them. I build these engines all day every day and most if not all of what you are talking about is integrated into race engines. Of cores we build them for the most power but also to run the whole endurance race, race after race. DM me if you would like and i will send you my Phone number

PS. As for some comments above we do live in a perfect world and you can buy Mahle Pistons from Mahle. I do it all the time. I run JE and Mahle just depends on the build and budget.

Gordon... parts noted in spreadsheet. GT manifolds = interesting idea. Think that would work with EFI. Singer has nice styling to their work IMHO. Air filter incorporated inside manifold is idea worth duplicating. Looks like there are ITB's below their manifolds...

http://forums.pelicanparts.com/uploa...1544292889.jpg


ITBs... also very appealing. But, because system adds more moving parts to engine, that cuts against grain of build. Mission is to head towards increased simplicity---less maintenance. Am envisioning GT intake with single throttle plate config.

http://forums.pelicanparts.com/uploa...1544292889.jpg


Question... will GT intake drop onto 3.2/3.4? If so, can see pursuing this direction.

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Take a look at post #189 here. http://forums.pelicanparts.com/porsche-911-technical-forum/991399-official-black-911r-build-starting-over-10.html#post10277593

Thanks Adam. PM sent you.



See that post reveals 3.6 manifold going on 3.0m heads. Is this an aspiration upgrade?

Yes. The plastic 964 intake has a two stage operation for low-midrange torque and high rpm power. This picture from a 964 Bentley document briefly describes how the 964 intake operates with the resonance flap

http://forums.pelicanparts.com/uploa...1544484043.jpg

You can see in the pictures that the 964 intake manifold has a throttle body with two plates. Within the intake assembly is another passage that opens above 5400 rpm to change the effective length of the intake path.

^^^ Thanks for notes Kev. I looked around for more info on 964 manifold. Found one for $25,000. EDIT: Found another 964 intake manifold listed for $3,300.

http://forums.pelicanparts.com/uploa...1544634323.jpg


What about 930 manifold? This can be had for build's budget. But does it fit 3.2/3.4? And does it add aspiration improvement value?

http://forums.pelicanparts.com/uploa...1544634738.jpg

umm. no. $25k? They are routinely on ebay for a few hundred.

the 930 manifold will not work for you. Too small volume and flow characteristics are designed around boosted air (pressurized flow) not vacuum driven flow.

The issue with adding the 964 manifold is having an ECU to drive the plenum. The vacuum pod gets a signal from the ECU. YOur 3.2 Motronic ECU will not have this. And you can not add it. This can be done with a stand-alone ECU.

Thanks Jamie. Am planning on EFI & ignition. Megasquirt 3 is currently being researched. Did just find 964 IM for $3,300...

http://forums.pelicanparts.com/uploa...1544637945.jpg

Some advice if you wish to take it.

Disassemble the engine first and find out what is wrong and what needs to be repaired. This may take more $$ than you think.

Then set a budget.

Then ask yourself, what are my performance goals? The two are typically poles apart.

You now have 3 numbers you can work on.

"Design" your upgrade on paper, having researched all of the costs. You may have to compromise on your "wants" to fit the budget. You have to decide on what sort of build quality you want.

I think $17K could be on the low side. The danger on these builds is to "go down the road" where you cannot return.

That intake you first pictured isn't a 964 intake. Looks like a GT3 intake and must be a special one for $25K because an entire GT3 engine can cost that much.

Rothsport has developed an individual throttle body intake system using the 964 manifold and they typically manage it with a Motec ECU. It's very common to have a RPM triggered output with a fully programmable ECU.

That intake assembly from FVD for $3300 is still highly overpriced. Like Jamie said, you can find them for much less. http://forums.pelicanparts.com/porsche-911-used-parts-sale-wanted/1005414-964-intake.html

Article (Bisi commentary) supporting premise that ITBs offer more even air intake per cylinder than a TB on manifolds.

https://www.drivingline.com/articles/air-cooled-911-intake-revamp/

Idea of our engine builds being the "road with no return" ...that's darkly comical! Agree with you that once inside, the unexpected is a likely find. Will deal with that once there. If I can stay focused on the goal without being torn apart by surprises or seduced by +HP questing... I think I can make $17k. We'll see. (Now and then I have to flog myself back to the goal. Last temptation was supercharging.)


Yeah, pictured one was $3,300 manifold.

Link to $25,000 intake... 993/964 RSR Intake Manifold

Am now finding them as you and Jamie mentioned... hundreds of $s.

The upper one is a Thielart(Sp?) 964RSR/993RSR resonance manifold, you don't need that, probably 964 plastic or 993 nvr would work best w/ itbs, The gt3 is could also work but is designed for a much higher revs

a turbo manifold would be a poor choice for a n/a motor