Carrera 3.2 Engine - Oversizing to 3.8?

[KeoRS]

Good day to all;

I was reading my copy of the Porsche 911 Performance Handbook. On page 170, there is a list of piston and cylinder sets for different 911s, including oversized combinations.

It lists a 3.0/3.2 oversize to 3.8L piston/cylinder set (100 x 76.4). I've read quite a few on 3.4 conversions. There is less information on 3.5 conversions... and I've yet to see someone who has done a 3.2 to 3.8 conversion.

Has anyone ever seen/done this. Are these piston/cylinder sets still in production? I can't seem to find sets specifically to oversize a 3.2. I was able to find 100x76.4 3.8L sets made by Mahle and JE Pistons, but they advertise them as 964 oversize kits. Are these compatible with a 3.2 core and would any additional modifications be needed?

Here is the link to JE Pistons website, look towards the bottom:
http://www.jepistons.com/Catalogs/Automotive/Porsche.aspx
3.8 102mm 76.400 Compression of 11.5 (Kinda high for North American gasoline, no?)

Here is the link to the Mahle set sold here on Pelican Parts:
http://www.pelicanparts.com/cgi-bin/smart/more_info.cgi?pn=PS102-015-M362&catalog_description=Motorsport%20Piston%20%26%20Cy linder%20Set%20%2D%20%33%2E%38L%20RSR%20%28%31%30% 32mm%20bore%2C%20%31%30%37mm%20Sleeve%2C%20%31%31% 2E%35%3A%31%20Comp%2C%20Slip%20In%29%2C%20%31%20se t%20per%20car%2C%20RSR%20rods%20required%2C%20%39% 31%31%20Carrera%2F%34%20%28%31%39%39%35%2D%39%38%2 9%20


On a side note, I hope all fellow northern pelicans are taking the opportunity to ride in their p-cars on every sunny day before snow starts to fall and it's yet again time to store our beloved cars.

Thanks in advance for any feedback on this type of conversion!
Kev

[NY65912]

Of course it can be done.





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 will be able to turn to 8600 rpms, but we are holding it down to under 8000 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

52mm ITB’s big injectors – FP Regulator (plus all kinds of other stuff)

Smart Racing Oil Filter Console

1¾” Nabel’s Headers into an (M&K Sport Muffler for street) M&K Shorties on the track

Spark and Fuel controlled by Haltech E-8 Engine Management System
Crank Fired Wasted Spark Accel Coil Packs

Light weight Al flywheel and HD clutch

[88-diamondblue]

NY65912, very nice just doesn't say it well enough, that has to be one hell of a ride with that engine in it.

The link that you gave for the Mahle's are for a 964 3.6 engine to be upgraded. Looks like the Nickies will take you to a 3.7 with machine in cylinders. Enjoy a great project. Check with Camgrinder Dougherty Racing Cams for recommendations on the right cam for what you want from the engine. Wish I had the budget to take it to 3.7 as I am very happy with the outcome of my 3.4 rebuild.

[e3photo]

Man, that is sweet looking. What kind of HP you crankin?

Cheers,
Emerald

[NY65912]

Thanks guys, The real genius behind the 3.8 is Bill Rudtner. We collaberated and he made ithappen.

The engine did 365 to the rear wheels, with a 15% drivetrain loss I believe we were looking at 415 crank.

I had Bill make a less aggressive street map to be more user friendly on the street.

Due to health issues it has become more difficult to attend track events, but I hope to get back soon and use the more aggressive track mapping.

Oh yeah, it pulls like a freight train to 8600 rpm.

[KeoRS]

That's insane!

Thanks for posting this. It's really impressive. I'm sure it sounds amazing. This kind of setup is rare and I feel it has a bigger "raw" factor than a forced induction setup.

415hp NA... NICE!

Mike, what transmission is hooked up to your 3.8? G50? Did you change any gear ratios or are you running a stock transmission with an upgraded flywheel/clutch?

[NY65912]

Keo,

Currently I'm still running a stock 915 and have virtually no miles on this engine. I'm running a light flywheel and HD Sport clutch.

Plans do include a G50, and more suspension work IF I keep it.

Right now we are undergoing an IROC upgrade.

The big problem is my health.

Over the last year I have had a few problems and progress has been slow.

i was pondering selling the 3.8 and refitting a stock 3.6 in it's place for better street drivability as my track time is up in the air.

[KeoRS]

Hey Mike;

Sorry to hear about your health. It's awesome to see you on the boards! I hope the members are able to keep you on a positive mindset!

I really like the choice of engine mods you've done with your track project.

I'm sending you positive waves so that you get better soon and maybe you won't sell your track project after all!

Man.... what an engine....3.8 droooool

[smokintr6]

Mike, What is the exhaust setup like on your 3.8??

[NY65912]

Headers are George Nabel's European Racing Headers in 1 3/4" with an M&K Sport Muffler

[alniki]

Nice setup.
But headers in the second picture might have been put on the wrong sides.

[smokintr6]

Thanks Mike... I have a similar setup to yours. Keo, it might be an interesting reference for you, so I'll post some details. Your engine won't be quite like mine, because I have a lot of 964 & 993 parts, but it is important to understand "slippery slope victim" directly below NY's username

I'm running a 964 case with a worked crankshaft, and custom Pauter rods (longer) and JE 12:1 pistons. Stock 964 cylinders (only 3.6L displacement hahahah), 993 cam boxes modified for solid rockers. 993 3.8 RSR cams and port sizes, Vellios injection with autronic engine management. I am not running a super light flywheel and clutch combo. The sticking point has been trying to figure out an exhaust that won't choke off all the power, but isn't horrendous to live with. Right now I have a B&B system that is 2 in 2 out, and the droaning is unbelieveable, and unbearable. I have tried a flowmaster muffler, but all my throttle response went out the window. I have then next option picked out, but I'm getting sick of trial and error. At this point, I would settle for something that sounded good, even if I had to give up 15hp. Slippery slope almost seems like an understatement these days!

In all reality I'm probably running too much cam for the street. I can't seem to get enough flow through a muffler to take advantage of the high RPM horsepower. I really should go back to an 11:1 piston, and a more reasonable cam, but it's not in the budget for the moment.

[KeoRS]

smokintr6;

your setup looks brutal!

Does oversizing from 3.2 to 3.8 affect the responsiveness or driveability in any way that it might be better to opt for say a 3.5 or 3.6 oversize?

[NY65912]

I think the responsiveness on the street would be to use a more moderatley sized ITB.

I'm running 52mm. I am thinking of dowsizing to 50mm or thereabouts. I have yet to discuss this with the builder.

Since my direction will now be more street than track, I think a smaller ITB would be called for.

Drivability on the street, (as is) is like driving a bucking bronco.

BUT, when she catches.... hold on!

[smokintr6]

Mike, I wish I knew what size my ITB's are, because I don't have any trouble in town. my car runs like a kitten up to 4,000 RPM, and then Screams like a banshee until 7,500. Under 4k I don't make much more power than a nice 3.2, but above 4500, it's a different ball game. Quick WOT at 1500-2000 makes it a little mad, but I don't have a reason to do it. I had no trouble with standing starts for autocross. I'm sure you'll get it figured out.

Keo, have you considered buying a complete 3.6 engine to swap in, and sell off your 3.2? That is probably actually your most cost effective solution. You are rolling the dice on a used engine, but with due diligence you can ovoid most snares

[KeoRS]

Originally Posted by smokintr6

Keo, have you considered buying a complete 3.6 engine to swap in, and sell off your 3.2? That is probably actually your most cost effective solution. You are rolling the dice on a used engine, but with due diligence you can ovoid most snares

I have given it some thought, but I rather like the idea of knowing the engine inside out and being able to trust it's reliability for the years that follow the build. Also, from what I've been reading the 3.2 is a great platform to augment performance. Of course, it doesn't come without expenses.

However the whole process of deciding what exactly I'd like to build out of my engine is more than motivating. As they say... the journey is just as fun as the destination. ( if not moreso... how many people build crazy cars and then sell it off for the next "project" - which I don't plan on doing! My p-car is a keeper!)

So back to the technical stuff, guys. If I understand correctly, the minimum needed for the 3.8 oversize is:

-102mm X 76.4mm P+C set with 23 mm wrist pins (custom ordered I suppose?)
-Crank stroked to 76.4mm ?
-Dual plugs

Any thing else in the "required" category? Can the motronic handle the changes or would I absolutely need an aftermarket engine management system?

I understand that there are additional modifications to bring in order to obtain peak performance, but I'm just trying to understand what's required and what's ideal.

Any input would be awesome!
Thanks in advance, guys.

Kev

[NY65912]

102 mm LN Nickies Cylinders
3.2 Crank - Stroked to 76.4mm

Can't comment on Motronic as I am running Haltech.

Cam selection is critical.

[KeoRS]

Thanks for the quick reply, Mike!

Any updates on the 3.8 project?

Speaking of the Haltech eng. mngmnt system. Does that use the stock wiring harness or does that need to be updated as well? Are you satisfied with it as of yet?

Also, I completely understand that the cam selection is critical. If kept stock, I suppose it could run but it wouldn't be no where near ideal.

3.8 is soooo tempting. I'll research even more on it now!

Kev

[Henry Schmidt]

How about a titanium rod tytanium valve 4.0 liter?

[KeoRS]

Henry;

Droooooool. 4.0L

Looks like a killer engine. Is that based on a 993 engine? Seems like the shroud came from a 993. If it's a 3.2 case, I'm impressed. Quite the oversize... and I thought 3.8 was pushing it