3.2 upgrade help
 

I have a 3.2 motor ready to build up for fun occasional street & track use. I’m at a crossroad looking for advice on the best combination of displacement and cam upgrades that will work well with single plug Motronic on 94 octane?

No emission requirements, I can go with any combination on exhaust & chip. I currently have a SS single in, dual out aftermarket muffler The intake, intake runners, intake and exhaust ports have just been cleaned up of all casting imperfections and the case boat-tailed, all in anticipation of a displacement increase. Access to local machining is my greatest limitation so far, so for the most part I’m trying to do the majority as bolt on.
Using Stock crank and rods, with upgraded rod and head bolts.

Options that come to mind:

3.2 original P&C 9.3:1 cleaned up, mooned, new rings, and try hard to be happy with that. Feedback on perhaps leaving out the base shim rather than fly-cutting heads for small compression gain?

3.2 Euro 10.3:1 P&C, exhaust & chip recommendations?

3.4 Mahle Motorsport 9.8:1 P&C, single plug & stock cam, or performance cam, chip suggestions. Told expensive for marginal gain, anyone care to comment on this?

3:4 Nickies 98mm with JE pistons 10.5:1 single plug, compensating with ceramic coatings, water injection and or higher octane blending. Performance cam, chip & 1:3/4”headers

3.4 Nickies with JE pistons 10.5:1 dual plug and all the performance goodies.

What is the best bang for the buck? Anyone work out the most HP gain per $ spent?
Are there any options on modifying the Motronic to operate better with engine modifications? Perhaps substituting the airflow sensor?

3.6 engine swap!

Non of your options above will beat it.

I'm in a similar situation and personally prefer "3.2 Euro 10.3:1 P&C with improved exhaust & matching chip if the P&C are not too expensive.

A 3.6 swap is tempting but expensive and would probably hurt the resale value unless you can find a right buyer. Just my 2 cents ;)

Go with a stock 3.2 rebuild + chip/exhaust, and spend the savings on rebuilding your G50 with shorter gears.

I would love to start with a 3.6, considered it at one time but that option is out of the picture now just to far down the slippery slope with this one, thanks.
My stock P&C are within spec, so that is the cheapest way out, but I'm looking for more power.
Yes looking at gearing and weight loss also, but back to the topic I really would like some input on the proposed builds.

The other option that I played with and did not mention earlier was building higher compression, low boost turbo motor. That would be lots of fun to drive but big gamble at the same time with single plug and Motronic. Also I want to maintain maximum low end torque for Autocross

Low boost turbo is not an economical option, IMHO, unless you get it pretty inexpensive. Guess you probably cannot get both low end torque and high end hp without resorting to high displacement.

I'm in the middle of a 3.2 rebuild myself.

>>3.4 Mahle Motorsport 9.8:1 P&C, single plug & stock cam, or performance cam, chip suggestions. Told expensive for marginal gain, anyone care to comment on this?

Keeping 9.5:1 standard compression, cylinders bored to 98mm (3.4 liter) and replated by EBS in Nevada
JE Pistons
964 Motronic cam grind, or you could do 20/21 Webcam grind
ARP rod bolts
upper and lower head studs in steel *gasp*
Updated Steve Wong chip (911chips.com)
cat bypass, dual out exhaust, standard heat exchangers

If you stay under 10:1 no need to twin plug with 98mm, but you're at the limit. 91 octane minimum.

And, twin plugging realistically adds a fair amount of expense between the dizzy, signal splitter, extra wires, extra coil, etc. ($1500+) Twin plugging is desirable, but recognize what it really costs before you go down that path.

With the setup I am doing I am told the gains are not huge, but a 10-12% bump in rwhp and torque can be expected. On my 2600lb Carrera I think that is significant for the money spent.

Honestly best bang for the buck might be to rebuild it with what you have (if everything is within spec) and turbo it. Especially if you have no emissions requirements.

Change MAF, exhaust, cam, and chip.

Any more new bits (like P&C) and you are not far from a 3.6 swap.

Yes in one sense your right "IF" this is all done to my 3.2 but consider that in doing a 3.6 swap I would still need the exhaust, chip, DME, wiring harness and everything else to do the conversion. These are all additional expenses over the cost of the motor and in the end I still have a used motor.
Thanks for your input but really I'm to far down this path now to to change directions.

I was thinking the same thing John. Many of my existing parts like intake plenum and heat exchangers are desirable upgrades to the turbos CIS fuel system. So in some ways going this route gives me a head start and reduces cost. I can also run my existing cams. I can place thicker shims under the jugs to drop the comp ratio a bit, still run the domed Motronic pistons with a single plug. The additional fuel requirements and combating detonation can be meet with the addition of a inexpensive water/alcohol system. For a measure of caution I could install a bung for a wide ban O2 sensor to read AF and measure exhaust temp. Apparently there is a sudden drop in combustion temp just prier to detonation. Can also add a stand alone knock sensor, with a warning light on the dash. These are relativity cheap systems to install and would add a measure of safety on any modified engine.
The boost requirements are minimal so even a K26 would do the trick.
Lots to consider and that is why I'm here to get all the feed- back I can get.
Thanks for every one's input

Does Paxton put out a unit for a 3.2? Which would give more effective performance, a root type blower, or a true turbo? Which would be more effective as far as power is concerned, and which would be more cost efficient to run? I have seen very little data on NOS systems for a 3.2, I believe the reason is that it is not really a sound way to achieve more power with the air-cooled 3.2 engine. I have built 3.0 liter V6 conventional type engines, and fabricated custom headers and added single or even dual stage systems with up to 150HP shot NOS systems for them, without problems, but I don't think the 3.2 would be a good candidate for that type of upgrade, but... maybe I am wrong in thinking that??? Any thoughts?? Good luck with it!! Tony.

Thanks for your input John,

I think your right, in the end its more bang for the $,, plus it opens up a much larger window for HP potential on future builds. HP is addicting and eventually we all want more, more, more! lol

After lots of research, internal debate and sleepless nights I have decided to go the Turbo route. No turning back now, ordered APR rod bolts, and head studs in preparation and a Dansk header.

My build - which I think was a good bang for the buck

3.4 mahle 9.8 to one jugs
~ 1MM taken out of pistons for valve pockets
Single plug
Magnecor Wires
extrude hone intake
993ss cams (Dougherty Racing Cams)
arp rod bolts
Supertech Head Studs
enlarged throttle body
competition springs and retainers (EBS)
993 Flipped Flange Heat Exchangers
MK 993 Bischof flange muffler
Steve Wong custom chip to pull it all together

JeremyD... what did your set up wind up putting out for fwhp and or rwhp ??
I followed your build some time ago but I can't remember how it turned out.
Thanks for posting your build info! Anything you would of done differently reflecting back now ??
Bob

in signature - 244.3 rwhp

No replacement for displacement. A single plug 3.4 at around 9.8-10.0 compression makes for a very nice strong motor.

Hi Steve,

I agree with you " No replacement for displacement " and this was my intended route.
After much consideration and internal debate, I'm converting and going Turbo.
There are no emission constraints.

What are the Dyno figures (high low window) that you’re seeing with a 3.2 conversion using stock cams, single plug head, headers, non-restrictive exhaust, intercooler, Motronic and your Turbo chips? At what compression ratio, boost pressure and fuel pressure? Is a cam upgrade beneficial while maintaining the Motronics?

I figure if I can get an idea of the Maximum obtainable HP attainable within the Limits of the Motronic, I can properly match the rest of the components and purchase the ideal turbo & intercooler.

My intentions are to use my old PC’s for now. I can shim to reduce the CR down to about 8.8/1 if it produces better results.. The engine is still apart so this is the time to do it and I’m open to suggestions.
The exhaust and intake ports and intake have been cleaned up for added flow.

Still debating the following:

Possibly coating the crowns and combustion chambers with ceramic.

Water/Alcohol injection.

Your input is much appreciated, Thanks Paul

I'm no engine expert, but adding shims will mess up the squish area. Bad for pre ignition control...

having dealt with turbos for years, the constant tinkering, maintenance, heat, turbo lag, attention to operation, oil coking, proper shutdown procedures, discovering the limits of your hardware not designed for the torque (i.e. clutch, gears ... if you know what I mean) I just got tired of it all and guess you can say I prefer the 'no worries, no surprises' n/a instant response configuration. The fact that you're talking about intercoolers and alcohol injection has me thinking you're the type to head down the same path I did. No doubt, a turbo will have a engine deliver more torque and hp than you're going to get from a n/a motor, including a 3.6, but it's not as linear and instant, and if there's lag, especially from a single turbo, it can surprise you if the boost kicks in in the middle of a curve.

Have you driven a 3.6 transplant? A 993 motor in a lighter weight 911 body, with the shorter gears of the earlier trannys is scary brutal - like a giant 2-stroke motor.

Anyways as for options with respect to turbocharging the 3.2, have you looked in the 930 turbocharging forum. Lots of guys there who have BTDT, so check it out.