Jay,

I have been totally playing with the idea of going to TPC. I have heard nothing but good things. The bang for the buck is awesome.

In Canada, picking up a 965 is about $25k more. I can throw an S/C on my narrow body w/intercooler, put a wide body kit on my car, "show quality paint", for around the same. Which are my intentions.

Did you retrofit an intercooler? Clutch flywheel? New decklid and wing?

Last question, 0-60mph?

Thanks Jeff

 

I would have to have driven Jay's car to compare but from my standpoint the 3.6T is a totally different animal than the earlier 3.3l turbos especially the 4 speeds. Although there is a slight lag at low rpms, boost is on pretty full rather early and driveability is not an issue. The 94 is a pussycat around town and a Cheetah on boost. With the addition of the HF turbo, the on off power of the earlier cars is nonexistent and the car feels and can be driven like a high powered NA car except for the 1st 2500rpm in first gear.

Both SC's and turbos have their pros and cons and I don't see why an SC'd 911 wouldn't be a blast to drive. I would say that trying to sell an SC'd 911 will definitely be tougher than selling a stock turbo and slightly tougher than a modded turbo. But if you enjoy the car why would you sell it anyway.

 

Andy,
Some info is here in a previous post of mine:

https://rennlist.com/forums/performance-modifications-forum/90227-supercharging-of-knoxville.html

The PO spent $ 14k on my car 10 years ago converting it to widebody using all factory Porsche parts. They butt welded the rear quarters like the original 930s did. That's the only deviation from a 965 body my car has. The 965s actually had stamped quarters with the flares already there. The guy just wanted a normally aspirated, 2 wheel drive widebody.

Anyway, I am running a Centerforce clutch. Stock wouldn't last long. Big IC & piggyback ECU box so I can adjust timing & fuel curve. I bought the whole engine package from a buddy of mine who needed a stock motor so he could pass CA emissions. He had about $ 20k in the whole set-up inc. electronics. It was actually one of the first units SoK built back in '90. It is definitely not the cheapest way to go.

TPC seems like a much more reasonable alternative. If you intercool it & keep the boost reasonable, you should be fine. The old rule of thumb is .1 bar = 1/2 a compression point bump ie; my old 930 was an early car with 6.5:1 static compression so at full boost (1.1 bar), it was = to 12.0:1 . My current car was rebuilt by SoK & has a static compression of 9.0:1 so at full boost (.5 bar), it = 11.5:1. If you keep your stock CR which should be 11.3:1 I believe & ran (.25 bar) you would end up with about 12.5:1. Reality is your stock 964 probably has around 10.5:1 so you would be around 11.75:1. The only 964 motors I have heard of that had the actual published CR were the balanced cup & RSCS motors. Hope this helps more then confuses

 

True but again if you go to sell it how difficult will it be. Not everyone wants a turbo and a highly modified 911 is even tougher to find a buyer for.

The turbo's have never been drag cars. My car is a dog from 0-20, unless I rev the engine and drop the clutch (which I don't like doing) I would never attempt a drag from a dead stop, from a rolling start not even Dodge Vipers can keep up C5 Z06's go down real fast. From 60-130 is more of a test of power and the turbos have an edge in this area.

BTW Dan Jacobs from Hairy Dog Racing in CT has done a 3.6T install into a narrow body 964. Don't see why it should be too difficult.

 

Like Anthony said, turbos make power up high, superchargers down low. For track use, I would take a turbo hands down since you can keep it in the powerband there. I just prefer the drivability around town of my SC car over my old turbo hot rod. Both are great cars!

PS: My car will never see a drag strip. I just got in a hurry & nailed it that one time on the highway. Never again. I have a 500+ HP tri-power '64 GTO for those type of shenanigans

 

I hope Subaru is paying attention, the turbo lag in my WRX is pretty obvious. It's kinda like having the two cars mentioned earlier - one a little econocar station wagon runabout, the other a very fast, capable screamer (well, moaner, really) that happens to carry four people and luggage. Not a bad compromise as long as you learn to compensate for the turbo lag, but more even delivery would be nice...

 

OK, thanks Indycam, very cool.

 

This is a subject very close to my heart.I have been involved in a few serious SC conversions in the past.
On air cooled motors head temp is critical.Turbos raise head temps more than a SC.
There are two families of SC-Linear and square law(centrifugal )
The linear type does place a restriction on max boost @ max detonation sensitivity-about 4000rpm which is a limitation through the speed range.
Centrifugal SC have the characteristic of more rpm -more boost so can be sized so this is less of an issue but dont give 2000 rpm boost like a linear.
The static compression of a 964 is high but running compression is much lower due to the long inlet cam duration.This is why the simple boost/static compression sums dont work in the real world.
This is a huge subject and the "correct " solution depends on what end result
is needed and which problem is the biggest/most expensive to overcome.
Geoff

 

One of the problems with forced induction is that it inevitably raises air inlet temperatures, hence most turbos run with an intercooler. The TPC kit doesn't come with an intercooler as it is suggested that the low levels of boost will not raise air inlet temps to the degree that it will cause detonation; This is probably true in road applications but having been a passenger in a well known UK TPC equiped car on track I'd suggest this is not the full story, as this car definitaly went off after a few laps and the owner at the time was well aware of this anomaly to the degree that he sold the car because of it.
My NA 300hp car was faster in a straight line once the retardation by the ECU set in but before it did the performance was really impressive.

 

Most screw type SC have poor thermal efficiency so an intercooler is essential except that the sums have to be done on pressure loss/charge temp drop.If it was my choice ,with an air cooled motor,an intercooler would be high on the list.What is known as "customer preference" !!!
Geoff

 

I thlought I read somewhere on the site that they do now offer intercoolers for their superchargers. I think I had to dig to find the info... Or it may have been in an article that I read about TPC.

This is probably 6-9 months off for me. The new business is starting to take off and I need to devote all my time (and profits) to growing the business first.

 

Rick,
They offer an IC now:
http://www.turboperformance.com/Pors...C/993sckit.htm

 

Which makes you think; Does it or doesn't it need an intercooler?

If you're going down the way of intercoolers, and if you are then you really need to be considering dropping the compression, why not go the whole hog and turbo it and get much more power.

 

According to their site you don't need to drop the compression in either installation. It is kind of tempting isn't it? I'm planning on keeping my car for a good few years with a view to sorting the suspension and brakes first and then I'll do the supercharger which'll cost much the same as I would lose swapping cars....

Cheers,

David

 

Yes, but I bought my p-car for me to enjoy and not the next owner/buyer -- I guess it depends if you value the car for your own enjoyment in the "here and now" or just worry about future resale value.

Marc