3.3 turbo engine performance limits?

[ornas]

hi, again I am going through turbo engine rebuild. This time I would like to squeeze a bit more HP. I am going to do regular mods, such as ARP rod bolt, head studs, heads porting. This time I would like to lift is compression ratio, car should be more responsive at low rmp and should boost up faster. My goal would be not max HP, so I am not interested in larger turbo. What would be your recommends? 8:1? 8,5:1? more or less and why?

[spuggy]

Originally Posted by ornas

hi, again I am going through turbo engine rebuild. This time I would like to squeeze a bit more HP. I am going to do regular mods, such as ARP rod bolt, head studs, heads porting. This time I would like to lift is compression ratio, car should be more responsive at low rmp and should boost up faster. My goal would be not max HP, so I am not interested in larger turbo. What would be your recommends? 8:1? 8,5:1? more or less and why?

You don't need a bigger turbo, you need a better turbo. The 3DLZ is very, very, old design - and wasn't designed for a petrol sports car motor. Junk it.

K27/HF works very well; mine makes 6PSI @ 2400. If you're sticking with CIS, that's about as far as you can/should go.

Don't go over 8:1 - in fact, that's quite high; puts you at an effective C/R over 12:1 with .8 bar. I went with 7.5:1 - can always use boost control for more power.

You want better cams. SC cams work well in 930's - only slightly less power than 964 at the top end, and better low to mid-range torque.

Don't bother porting the heads UNLESS you want big power; small factory ports make more torque lower down - and 425 FWHP is not hard to get with stock wastegate and heads/valves - just add SC cams, good intercooler, decent headers and a hybrid K27. Use factory RoW heat exchangers if budget is tight; won't cost much power over aftermarket.

The restriction from the 34mm intake ports is irrelevant once boost comes in. By all means open them out to match if you're going to use a 3.2 manifold, otherwise leave them alone.

Certainly uncork the wastegate. Free-flowing muffler also good.

Twin-plug if possible; otherwise run as much off-boost ignition advance as you can; single-plugged 930 loves advance and this makes a huge difference to response, but you will need to lose the advance under boost. i use an adaptive per-cylinder knock detection/control system that does boost retard as well.

5-speed box also makes a huge difference to a 930 that isn't making massive power. Some say it isn't necessary - but I note that the Ruf CTR prototype "Yellowbird" was quoted at 469HP, commonly thought to have far more (based on a measured two-way top speed of over 210 MPH) - and had 5 speeds....

[ornas]

sc cams - you mean 3.0l engine?
what about 3.2 carrera cams?

should I also change conrods?

Originally Posted by spuggy

You don't need a bigger turbo, you need a better turbo. The 3DLZ is very, very, old design - and wasn't designed for a petrol sports car motor. Junk it.

K27/HF works very well; mine makes 6PSI @ 2400. If you're sticking with CIS, that's about as far as you can/should go.

Don't go over 8:1 - in fact, that's quite high; puts you at an effective C/R over 12:1 with .8 bar. I went with 7.5:1 - can always use boost control for more power.

You want better cams. SC cams work well in 930's - only slightly less power than 964 at the top end, and better low to mid-range torque.

Don't bother porting the heads UNLESS you want big power; small factory ports make more torque lower down - and 425 FWHP is not hard to get with stock wastegate and heads/valves - just add SC cams, good intercooler, decent headers and a hybrid K27. Use factory RoW heat exchangers if budget is tight; won't cost much power over aftermarket.

The restriction from the 34mm intake ports is irrelevant once boost comes in. By all means open them out to match if you're going to use a 3.2 manifold, otherwise leave them alone.

Certainly uncork the wastegate. Free-flowing muffler also good.

Twin-plug if possible; otherwise run as much off-boost ignition advance as you can; single-plugged 930 loves advance and this makes a huge difference to response, but you will need to lose the advance under boost. i use an adaptive per-cylinder knock detection/control system that does boost retard as well.

5-speed box also makes a huge difference to a 930 that isn't making massive power. Some say it isn't necessary - but I note that the Ruf CTR prototype "Yellowbird" was quoted at 469HP, commonly thought to have far more (based on a measured two-way top speed of over 210 MPH) - and had 5 speeds....

[WPOZZZ]

Typical upgrades to a 3.3 turbo motor would be SC or 964 cams. These are cams that are made for the 3.3 turbo motor with the SC or 964 cam grind. My 86 had bigger P&Cs and had a 3.4 displacement, SC cams, K29 turbo, B&B intercooler and exhaust. It pulled like a freight train to redline and had power to spare.

[tailwind22]

Originally Posted by spuggy

Twin-plug if possible; otherwise run as much off-boost ignition advance as you can; single-plugged 930 loves advance and this makes a huge difference to response, but you will need to lose the advance under boost. i use an adaptive per-cylinder knock detection/control system that does boost retard as well.

Spuggy, not to hijack the thread but could you comment a bit more about your knock detection/control system?

[spuggy]

Originally Posted by ornas

sc cams - you mean 3.0l engine?
what about 3.2 carrera cams?

SC and 3.2 cams are identical profile/lift, just timed differently. In fact, with the exception of the quietening ramps for the hydraulic tappets, I remember reading that 993 cams were the same as SC and 3.2 cams.

Dougherty Racing Cams Porsche 911, 930 and 964 camshaft profiles

Thing is, a 3.3 with SC cams drives like an SC with a big-bore kit. With a K27/HF as well, you can make .4 bar (6 PSI) by 2400 RPM with load...

So you have two entirely different cars - zoom around with light throttle load, revving it freely (and a 5 speed is great for this) - it's just a low-compression SC with a big bore kit/more torque. And you can spool the turbo now and again to make it pick up it's skirts and hustle.

When you remember that the loud pedal goes further than 1/3 open, it's still fun - but it's really not so light-hearted...

should I also change conrods?

The factory bottom end, with the exception of the cursed rod bolts the factory chose to make from string cheese (yeh, I spun a rod bearing from a missed shift/overrev), is pretty strong. Most people don't replace the rods unless they plan quite serious power - it's probably not actually necessary until you target is 600 HP and above - although if you have budget, a set of Pauter or Carillo rods will reduce reciprocating weight (and thus stress on the bearings).

Even a tuned 930 doesn't need to be revved much beyond 6000 - although they do sound quite incredible when you do that - so fit ARP rod bolts anyway so you can .

But it's counter-productive; mine makes peak HP @ 6100 and peak torque @ 5000 - with SC cams and a K27/HF @ .8 bar, Kokelyn, GHLs etc.

With a 3DLZ (but still with SC cams), it made max power @ 5680 RPM (just ran out of turbo).

The 3DLZ is pretty useless. Not only does it not make much power at the top, it tends to heat the charge more than an efficient turbo would. Exactly what you don't want. Couple that with a light-switch power band that does nothing! nothing at all! for ages and ages - and then hits you in the chest @ 3300 RPM... It's a drag anchor.

[spuggy]

Originally Posted by tailwind22

Spuggy, not to hijack the thread but could you comment a bit more about your knock detection/control system?

Sure; I installed mine in 2010. It originally just listened for knock, but now I run about about 6 degrees more timing than factory and use the boost retard to gradually bleed off the extra advance as boost builds - so I get the (significant!) benefit of improved throttle response off-boost, and arrive back to factory timing by .8 bar.

(Surprisingly, 930's don't seem to detonate where you'd expect. At least, mine doesn't.)

I primarily installed it to guard against bad gas or a clogged injector - although boost retard turned out to be very useful as well. But I posted this thread My J&S Safeguard paid for itself last week... when my distributor suddenly locked fully-advanced - 25 degrees at idle! - and the Safeguard saved the day...

John's a member here; his main web site is J&S Electronics SafeGuard Indivdual Cylinder Knock Control

The Universal deals with distributor (points, pertronic) and coil/CDI/Motronic systems Universal SafeGuard for Distributor Ignition

The Interceptor deals with "smart" coil-on-plug units J&S Eight Channel Interceptor.

And there's a Vampire model for "dumb" coils.

PM for my number if you like; more than happy to chat about it. I liked my Universal so much that I just bought an Interceptor....

[OttoB]

When my 3.3 turbo out of my 1991 was rebuilt, we used a 3.6 crankshaft from a 1994 case and increased the displacement to a 3.5, among other "while you're in there" mods... Noticeable difference and highly recommend if you're re-doing yours...

[RarlyL8]

You don't say what mods the engine has now (if any).
Our tuned headers, muffler, IC, 7200, SC cams yield 350+WHP at stock boost.
Boost threshold is ~1600rpm with full boost before 2700rpm. Added 100+ft/lb of torque over stock by 2500rpm. Driveability is much improved without changing compression. Standard fuel is retained by not changing boost level. The 3LDZ yeilds a bit more lag and a bit less horsepower but still vastly improved performance.