EFI turbo build?

[krikra]

I'm going to build myself a nice EFI turbo engine. I'm not new to building turbo engines but I am new to porsche engines.
I'm in a position where I can chose to build it on a 3,2 engine or I can start out with a 930 3,3 turbo engine. I would like some advise as to what engine would be best for my plans..

No matter which of the engines I chose, I'm planning the following:
- Change out pistons+cylinders
- Nice set of aftermarket turbo manifolds with a GT35 turbo
- EFI with some aftermarket ECU
- Big intercooler
- lots of other things..

Do I go with the 3,3 turbo engine and change for 3,2 intake manifolds plus all of the above.. Or is it better to use the 3,2 engine as starting point..?
I understand that the crank + other parts are the same in the 2 engines.. But not sure if there is anything else making the 3,3 turbo engine a better starting point?
There is maybe the heads being more heat resistant in the turbo engine.. but the 3,2 heads flowing better..

Advise needed from people with experience in such builds

[krikra]

my goal with the build is a very reliable street engine with 500hp

[beepbeep]

I would use 3.2 engine as intake is already there and matched to cylinder heads. Crank is the same, so are the rods and rod bolts (as far as I remember). 3.3 engines are more expensive and you will need to buy Carrera intake and then port-match it to (narrower) 930 heads. That isn't trivial as injector notches will not align.

With 3.2 engine you will get plenum/fuel rails, bigger port heads etc. You loose turbo scavenge pump though so you need to install it. But it's probably easier to do than porting 930 heads to correct dimension and doing the messy notch-realignment job.

I would use 3.2 engine, a set of JE pistons and H-beam rods, 930 scavenge pump etc.

[Dynamohum]

Originally Posted by beepbeep

I would use 3.2 engine as intake is already there and matched to cylinder heads. Crank is the same, so are the rods and rod bolts (as far as I remember). 3.3 engines are more expensive and you will need to buy Carrera intake and then port-match it to (narrower) 930 heads. That isn't trivial as injector notches will not align.

With 3.2 engine you will get plenum/fuel rails, bigger port heads etc. You loose turbo scavenge pump though so you need to install it. But it's probably easier to do than porting 930 heads to correct dimension and doing the messy notch-realignment job.

I would use 3.2 engine, a set of JE pistons and H-beam rods, 930 scavenge pump etc.

Goran,
I'm in the middle of a 3.2 turbo conversion with a 350 to 400 hp target. Question what VE to use on calculations? To match a Garrett turbo to the my desired shifting power band of approx 3000 to 5000

http://www.not2fast.com/turbo/glossary/turbo_calc.shtml

As you pointed out E85 is the other option and I'm looking at also. What injectors and fuel regulator would you recommend?

[930gt-40r]

+1 on the 3.2 engine
you will also need sodium filled exhaust valves, some larger piston squirters would be nice, and cams of your choice.

To tell you the truth- I wouldn't use either motors- I would go with a non turbo 3.6 with sodium filled exhaust valves, pauter rods, stock 993 turbo pistons/cyls, and have it ready for 600+ or a verrry easy 500. I say this because it is already twin plugged, has 964 oil pump, nasty heads, nasty plenum, fuel injection, twin plug distributer...etc. This is the way I would have gone if I could do it over again without a question. Did I also mention that it would be a 3.6 liter?....

[Dynamohum]

Originally Posted by 930gt-40r

+1 on the 3.2 engine
you will also need sodium filled exhaust valves, some larger piston squirters would be nice, and cams of your choice.

To tell you the truth- I wouldn't use either motors- I would go with a non turbo 3.6 with sodium filled exhaust valves, pauter rods, stock 993 turbo pistons/cyls, and have it ready for 600+ or a verrry easy 500. I say this because it is already twin plugged, has 964 oil pump, nasty heads, nasty plenum, fuel injection, twin plug distributer...etc. This is the way I would have gone if I could do it over again without a question. Did I also mention that it would be a 3.6 liter?....

Hi Kris,

Re: 3.2 exhaust valves are already sodium filled, or at least mine are. According to Wayne's Rebuild book, There is a little divit in the middle of the face from where they fill the valve with sodium during manufacturing.

Re: the bigger piston squirters.
On my own build I'm going with a Ceramic Thermal Barrier coating on the piston crown to reduce heat loading the stock Motronic pistons and have abraded the undersides, to increase the surface cooling area exposed to the piston squirters. Me thinks that this should be enough insurance for my target (350 to 400 HP window) build.
Beyond that window it gets expensive and is beyond my budget.

Check this calculator out and look at the fuel octane needed!
http://www.turbofast.com.au/TFcompB.html

if check out his site there are a few other java calculators that are handy.

My favorite so far is this one: http://www.not2fast.com/turbo/glossary/turbo_calc.shtml

[beepbeep]

Originally Posted by 930gt-40r

+1 on the 3.2 engine
you will also need sodium filled exhaust valves, some larger piston squirters would be nice, and cams of your choice.

To tell you the truth- I wouldn't use either motors- I would go with a non turbo 3.6 with sodium filled exhaust valves, pauter rods, stock 993 turbo pistons/cyls, and have it ready for 600+ or a verrry easy 500. I say this because it is already twin plugged, has 964 oil pump, nasty heads, nasty plenum, fuel injection, twin plug distributer...etc. This is the way I would have gone if I could do it over again without a question. Did I also mention that it would be a 3.6 liter?....

I agree. If you hunt for extreme power output, turbo-converted 3.6 N/A engine is the way to go. But budget will grow accordingly.

Any way you see it, 930 engine is probably next-worst option (3.0SC being the worst if you don't count old stuff)

[beepbeep]

Originally Posted by Dynamohum

Goran,
I'm in the middle of a 3.2 turbo conversion with a 350 to 400 hp target. Question what VE to use on calculations? To match a Garrett turbo to the my desired shifting power band of approx 3000 to 5000

http://www.not2fast.com/turbo/glossary/turbo_calc.shtml

As you pointed out E85 is the other option and I'm looking at also. What injectors and fuel regulator would you recommend?

Work backwards by entering N/A 3.2 values and adjust until you reach rated power and substract couple of %. That would bring you near.

VE depends heavily on cams, so there is no clear answer.

Also, remember that matching turbo size so efficiency best at power peak will give you very laggy engine. All manufacturers "downsize" turbo to reach reasonable trade-off between driveability and power.

P.S. Chart power estimate seems to be a bit pessimistic with OEM 930 values...

E85 means 40% bigger injectors than petrol ones. So just multiply calculated figures with 1.4 and budget for more fuel flow (pump-wise)

[930gt-40r]

Originally Posted by Dynamohum

Hi Kris,

Re: 3.2 exhaust valves are already sodium filled, or at least mine are. According to Wayne's Rebuild book, There is a little divit in the middle of the face from where they fill the valve with sodium during manufacturing.

Re: the bigger piston squirters.
On my own build I'm going with a Ceramic Thermal Barrier coating on the piston crown to reduce heat loading the stock Motronic pistons and have abraded the undersides, to increase the surface cooling area exposed to the piston squirters. Me thinks that this should be enough insurance for my target (350 to 400 HP window) build.
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Didnt know that about the 3.2 valves
As far as the squirters go- if your goin for 350-400 you should be fine

[JBL930]

Does it not matter that the turbo heads are made from RR350 alloy? And the NA heads are not?

[930gt-40r]

It depends- some people get lucky with it while others not so much. I believe that it depends on the tune

[mppickett]

The 3.3 engine has the better oil pump if I'm not mistaken. The 3.2 has better cylinders (fully finned).

[hobieboy]

Originally Posted by beepbeep

Any way you see it, 930 engine is probably next-worst option (3.0SC being the worst if you don't count old stuff)

It depends if he really just wants an engine or a car 930 comes with lots of suspension pieces that may worth the difference if he needs a car for the engine (or unless going all out with everything mod-ed)

[waynesco1]

3.3 crankcase main bearing bore 65mm.
3.0 crankcase main bearing bore 62 mm.

3.3 Crankshaft has two counterweights per crankpin.

3.0 The oil supply groove (bearing No. 8)
3.3 Oil supply is in the bearing journal .

3.0 Crankshaft , stroke 70.4 . mm. Main Journals - Bearing No. 1-7 57 mm. Bearing No. 8 31mm
3.3 " " 74.4. mm. " " - " " 1-7 60 mm. " " 8 40mm

3.0 Con-rod Journals 52 mm. Shoulder to flywheel oil seal 65.0 mm.
3.3 " " " 55 mm. " " " " " 90.0 mm.

3.0 Connecting rods A- dimension 127.8 mm
3.3 " " A - " 127.0 mm

3.0 Flywheel Mounting 6 bolts washers on bolts 44 mm whole circle diameter
3.3 " " 9 bolts no washers on bolts 70 mm " " "

3.0 Oil pressure pump gears width 43 mm
3.3 " " " " " " 51mm 19% increase in capacity

3.0 Scavenge pump gears width 58 mm Alum Housing
3.3 " " " " 80mm. Housing change to cast iron increase of 38%

3.0 Cylinder head washers under the cylinder head nuts 22 mm.
3.3 " " " " " " " " 24 mm.

3.3 Distributor rotates anticlockwise

3.3 Pressure plate 30 mm thicker

[TimT]

so many variables....

we have built 3.3l @ over 600

3.2 over 700

3.8 watercooled which we call a 7&7... 700 hp 700 lb/ft torque..

You can make massive hp with any of the choices you outlined..

The NA 3.2 is nice ports are large. just turn around the intake... etc...

3.6 is good too.. just add the cost of those manifold adapters...

[930gt-40r]

I kick myself in the a$$ when I think about taking my 3.3 from stock to 500 horse when I could have done the same with much less money with a 3.6 motor. I am going to get more power out of my motor, but it would have been an easier build with a 3.6

[930gt-40r]

Originally Posted by TimT

so many variables....

3.6 is good too.. just add the cost of those manifold adapters...

Adapters to use which plenum? I would use the metal 3.6 plenum with a custom cross section and delete the resonance flap.

What are you suggesting? Or are you talking about a 3.6 plenum on a 3.2 (always wanted to try that)

[TimT]

Adapters to use which plenum?

To use a 3.2 plenum on top of a 3.6 which works very well..

the other pressurized 3.6's we have done usually have custom plenums

Haven't built a blow through vario-ram yet

[930gt-40r]

Originally Posted by TimT

To use a 3.2 plenum on top of a 3.6 which works very well..

the other pressurized 3.6's we have done usually have custom plenums

Haven't built a blow through vario-ram yet

I have never seen a 3.2 plenum on a 3.6, I would assume the 3.2 plenum would need serious porting to keep up.

A blow-through VarioRam would be nasty, but you would need an extra channel on a stand alone system in order to run it.

[krikra]

Thanks for all your inputs!
Maybe I should add that the car in question is a late 80's 930. So I'll have 930 brakes, suspension aso.. I probably have both engines available, so its just a question of choosing the one best suited for my build. Also forgot to say that I'll probably twin plug it now that the heads are of and I'm going with a standalone system anyway.

From the replies so far it does sound like there is good reason to use the 3,3 engine because of the bigger bearings, oil pump and the other mentioned things.. I had been told that the crank was completely the same in the two engines? Doesn't sound like it from what "waynesco1" is writing. If the 3,3 also has a better crank that's another good reason to chose 3,3 for the build.

So the only couple of things in favour of the 3,2 is that it has EFI intake manifolds and the better flowing heads?

Hmm.. I'm slowly leaning towards the 3,3 engine. But keep your arguments and ideas coming! It's really helpfull.