3.2 engine: how to increase performance?

[911hillclimber]

Keeping this topic off my Hillclimb thread, but my stock 3.2 is utterly original, so maybe giving 220 bhp (has an old set of rusty 2.7 RS headers on).

Looking at the Anderson book last night, it seems there is not much to be done with this engine other than cubic inches and Webbers.

One of the nicest things about my 3.2 is turn the key and it starts. I had webers on my original 2.2 and it was horrid to start and warm-up. I love fuel injection and the DME so what are my options?

Seems I can go to 3.4 without a machine shop (bottom end also stays intact), or a glorious 3.5 and a total tear-down. (etc)
I do not want to go crazy or ruin the car, so how about dropping a 3.6 in there?
I doubt the 915 will tolerate it etc?

Seem to be in a bit of a corner, but any comments or thoughts?

Graham.[8|]

 

[38F3E1]

A 993 3.6 will fit in there. You will need a G50 box though. Why don't you give Colin Belton at NineMeister a call as I am sure he could give you good advice on your options (and he is a rather good hillclimber to boot).

Ian.

 

[911hillclimber]

Agree on both fronts about Colin!
Don't want to go made though as the 911 Plan in 2008 is for a budget year so I can buy a real racing car for hillclimbing.

As we know, the G50 box is not a swap for the 915, and I think the 993 engine is a bit limited on bhp over the 3.2 in stock form.

Can't help but think the 3.4 is the best way, with DME, matched injectors and fresh SSI's and let Bob mapp a chip for the DME or even ditch it for an Apexi FC (as I have in my Impreza.)
Could make good use of a solid torquey 300bhp engine output.

 

[burrow01]

ORIGINAL: 911hillclimber

Agree on both fronts about Colin!
.

As we know, the G50 box is not a swap for the 915, and I think the 993 engine is a bit limited on bhp over the 3.2 in stock form.

Could make good use of a solid torquey 300bhp engine output.

Standard 993 Varioram is 285bhp, and will go to 300 fairly easily with a remap. My non Varioram 993 is noticibly torquier than my previous 3.2

Pete

 

[911hillclimber]

Thanks Pete. The issue will be the gearbox I think as changing the rear tube on the car does not appeal!
A loose engine and G50 box will cost a lot more than a 3.4/3.5 on the 3.2 base?

Graham.

 

[Tony]

If you do talk to Colin, ask him about motec on a 3.2 - I know it's something they're looking at - would keep the smooth running easy start stuff as well.
3.6 is a fairly straight forward job - there's a few converted cars around - It's what the PCT guy's did before building their 996. Capacity increase probably won't gain you too much without changing cams - and that probably means chaging injection or fitting carbs - makes a 964 or 993 engine almost a bargain[]

Tony

 

[911hillclimber]

But I'm stuck with the weak box at 250 lbft (ish) or is the 3.2 aluminium box that weak?

 

[Tony]

It's not that weak, several cars running in P1 with more than 250 bhp and 915 boxes. Article by Chris Harris in GTPP about his lightweight hotrod has a Tuthill built (3.4 I think) with 300+, seem to recall there was something about what the limitations of the 915 are.

Tony

 

[38F3E1]

You also might want to talk to the team at JZ Machtech. I have just come back from an open evening there and we had a very interesting chat about performance mods and earlier engines. They have a lot of experience with this stuff and would certainly give you another perspective.

Ian.

PS I believe you can get a short G50 box (a G50 with shortened bellhousing?) to allow it to be fitted without the torsion bar tube mod.

 

[911hillclimber]

Yes, there is a short G50 made in the USA (Patrick Motors I think or similar).
Must need a different input shaft and /or clutch mix too.

If I can't sell my hot Impreza then I might simply develop the 911 to its 4th engine level.
Might call Bob Watson and see what he has to say too.

If I do this it must be a DIY low cost job.

Just to compare things:

In the Impreza world my 2 liter is running 370 bhp/360 lbft and you can race or visit your Aunt in it.

A bullet proof box is £2000 and a 500 bhp mod will cost £4000

A 993 engine will cost about £3000? A G50 about £1500?

Sell my 3.2 and box for about £2000 tops so that will be about £2500 for a 90 bhp engine increase and a strong box.

 

[38F3E1]

BTW I believe the Impreza engine will fit in the early 911 no problem. :- D

 

[911hillclimber]

I bet the gearbox will too converted to 2 wheel drive!
Bloody cars and going faster![]

 

[38F3E1]

I am sure somebody has actually done this with a 912 so I was semi serious. I believe a VW camper van has also had the conversion. LOL.

 

[911hillclimber]

Finally, I think by faithful 3.2 is showing the signs of stress and strain.
I have some blue smoke on the over-run apprearing.

Need to get a leak-down test done down at Bob Watson's to see if bores or valve stem seals.

If the top end needs to be done( strictly DIY), may as well go for a 3.4

I've looked around and seems they are quite hard to find.
The ones in Automotion catalogue look good and the £/$ rate might help.

Anyone have any sources for a piston/barrel set?
Gaskets etc easy from Bert Gear, but the rest?

I'll leave the crankcase alone as it is good.
Should add the car runs well, so it's not too bad yet, and the oil is 3/4 between low and high.

Graham.

 

[IanHighfield]

Graham,

This is a long but 'must read' Pelican article on a 3.2 -> 3.5 conversion.

Note it is a 1988 thus G50 box though.

http://forums.pelicanparts.com/showthread.php?s=&threadid=181728

Part II is here :-

http://forums.pelicanparts.com/showthread.php?s=&threadid=186906&perpage=20&pagenumber=1

Here is the opening post

==========================================================================

Well,

Summer is unofficially over in Southern California and it's now time to take the 3.2L motor out of the car for the performance rebuild. The motor has 88K on it and is being rebuilt due to one or more bad valve guides. Will know soon enough how many are bad (or even if the problem is the guides!!!). Car has intermittent blue smoke at idle (not start-up). Will go for a couple of weeks without smoking and than for a day or two spews blue clouds of smoke at a light. My guess is that the valve stem seal is moving around, which is why the smoke is so intermittent. Oil consumption is still 1,400 miles a quart which is acceptable.

The car was on the dyno (Dynojet) today to get a baseline for the performance improvements to follow. With a Steve Wong chip, Dansk premuffler and Dansk 2 out muffler, the motor made 3 runs total. The first run saw 197 rwhp and the two subsequent runs saw 198 rwhp. All numbers were SAE corrected. Max torque was 182. Seems to be in the ballpark what other people are getting with the same/similar mods. Kudos to the gentlemen who got 219 rwhp with similar mods. I'm not even close but I guarantee I will surpass that with the new motor!

We than took the motor out this afternoon, transported it to my buddie's machine shop and placed it on the engine stand. Tomorrow I will remove the exhaust, the Motronic injection and see how far I can get into the longblock. Bear in mind that my friend and I are doing this after hours.

This will also take alot longer than normal because I am writing a series of articles for European Car Magazine detailing the build and options that are available to SC and Carrera owners. Basically every thing I do I have to stop and take pictures, both for possible publishing for the magazine as well as for my own documentation.

What did we find while removing the motor? The first thing we noticed that will need replacing is the clutch slave cylinder. There is a small whole in the rubber boot that pisses fluid when squeezing it. Next thing I found is when the rear swaybar was being removed one of the rear swaybar mounts is beginning to crack. They are the original mounts as far as I know, but they are also the reinforced versions. Last, after removing the transaxle from the motor, it looks like the main seal is beginning to weep as well. Everything else external seems to be in good shape, we'll see what things look like internally in the next few days.

The 3.5L motor has the following specs:

100mm Mahle Piston & Cylinders (MI/Carb Piston shape)
10:1 - 10.3:1 CR (goal)
993 Twin Plug Distributor with ANDIAL Motronic Signal Splitter
ARP Head Studs
ARP Rod Bolts
Web Cam 20/21 Camshafts
AASCO Performance Valve Springs
Extrude Honed Intake Plenums
Bored out Throttle Body
Magnecore 8.5mm Twin Plug Wire Set
Boattailed Engine Case
Polished (not ported) Heads
European Racing Headers by George Narbel
Dansk 2 in 2 out Stainless Muffler
Custom Steve Wong Chip for Twin-Ignition
Hardware/Sheet Metal powdercoated, cad plated, etc, etc

The motor is destined for street use with limited track days and thus will retain the std. Motronic and will run using our pathetic 91 octane available in California. Other than the headers (which the stock heat exchangers can easily be refitted in a couple of hours), the motor will be CA smog legal. The heat will be gone but the a/c will be retained (the wife will drive the car from time to time and she insists).

I will post some pics from time to time as things progress but I also have an agreement with the magazine and thus they have first rights for publication. I can only post pics that won't be used for publication. Since the "before" and "after" dyno charts will be published, I can't post the "before" dyno graph from today. Since I am also doing this afterhours, I can't spend a bunch of time on the computer loading images. Posting progress for the most part will have to do.

I know some of you are probably saying to yourselves why bother with a 3.5L from a 3.2L when you can just transplant a 3.6. The answer is two fold: I wanted the original engine case for the car and the cost for me to build this motor is WAY WAY less than sourcing a used 3.6L and conversion pieces. Thanks to European Car Magazine for helping to make this happen.

Special thanks to Vision Motorsports in Laguna Hills, CA for dyno time, engine removal and storage of the car for the next few weeks/months.

The goal for the project is 280 FLYWHEEL horsepower, or 238 rwhp if you use the 15% driveline loss that everyone seems to use. Why 280? Because with 3.5L, that is 80 horsepower per litre which is approximately what Porsche's most powerful street engines put out. The 87-89 Carrera only puts out 67.8, but the 2.7 RS puts out 77.78 and a 3.6 Varioram puts out 79.17. If I can get in the same ballpark as the latter two I will be quite pleased. Will provide plenty of punch even for my 2800 lb. Carrera.

Will I get there???

Ralph __________________
1988 Carrera w/ 3.5L Twin-Plug

===============================================================================

ATB

Ian

 

[Gary C]

Is a turbo out of the question ?

Would involve lowering compression and would need 930 headers & plumming plus a good injection/ignition package but would give you all the power you could ever need .

 

[911hillclimber]

Thanks for the info!

The 3.5 need the crankcase m/c'ing out, and I'm not ready to split the block but it is little extra effort when the rest is off!
I did a full crank-up rebuild on my 2.4 E engine so no stranger to the engines.

He has quite a spec there, and beyond my desires to be honest now I have the Lola to think about.

I want to get the 3.2 back to rude health, and even a stock 3.2 top-end will do.

I wonder if it is simply valve stem seals?
I've read that you can change them without stripping the heads off using compressed air fed to the cylinder via the spark plug hole with the valves shut.
Best to slip the engine out for that I think, but sounds feasible. Chance to check the clutch too.

Full bore Championship weekend at Loton Park this weekend! Great track!
(www.hdlcc.com)

Usual mini-report on sunday evening.

Trip to Bob's coming up!