Why Are Turbos Unwanted
 

It seems that everybody is chasing speed here but the majority are attempting it with na cars. Is it the higher entry cost of the turbos? More/higher maintenance? Higher engine rebuild cost? Turbo lag? Just curious, it seems to always take longer to sell the 930s..Whats your opinion?:confused:

$$$$$$$$$$

Opinion: turbos are a crude way to make power, and just as rear-wheel drive and rear/mid-engine are the gold standard, so is natural aspiration. Quicker, more linear and more predictable response. The people I know who have raced various turbocharged Porsche professionally admit that what you do, basically, is drive around the corner and then use the brute force to eat up the straights. Little finesse involved. As I said, purely opinion.

Stephan

Most folks are afraid of turbocharging, as in the unknown.

I kinda want one. I like finesse, but I like the brutal characteristics of a turbo also.

I think the Porsche Turbo is every mans boydream but at the same time a bit frightening both to drive and pay for.

I have to put in a plug for Protomotive. I converted my NA 3.2 over a year ago and I've put about 8 K miles on it. These are street miles, no track.

The car was good BT (before turbo), but now it is incredible. Smooth and exhilerating beyond words. It is a well designed turbo system, and has so far been maintenance free. Thank you Todd.

It's also nice to know that you can suck the headlights out of just about anything else on the road, even if you don't do that sort of thing....

Any chance of seeing some pics of the install? Which stage did you get?

930s seem to go somewhat tangent to what the early Porsches and Loti were. They often go against the general mindset of some Porsche faithful in that to build speed you lighten and balance the car. With turbos you worsen the balance, add weight, reduce responsiveness, decrease durability, and obviously increase horsepower incredibly.

The funny thing is that if you ask any "non-Pcar" guy which Porsche they would want, its almost universally the turbo. Some have said the street turbo was for Hot Rodders that just happen to drive a Porsche. As a guy coming from V8's myself, I crave a turbo...but after I learn how to drive my NA.

I think one thing that slows the 930 sales is not the "value" but the cost of ownership. Cost of ownership is with 996's and therefore you've got a smaller audience, I believe. Do many of us want one to add not replace our NA, I believe so. But there lies the other problem, we want one as our second 911.

It is stage 1 with intercooler. Here is the link to the install and pics:
http://forums.pelicanparts.com/showthread.php?s=&threadid=176597&highlight=protom otive

P.S. I have no relationship with Protomotive other than as a customer.

Grab a favorite beverage and sit down for a nice long read.
350's rebuild saga shows what is involved and also the HP junky while you are there disease. Also note the amount of time it has taken, with a moderate budget, expensive things need to be spread out a bit more. ;)
http://forums.pelicanparts.com/911-engine-rebuilding-forum/115632-rebuilding-my-930-a.html

david 89 turbo cab

Almost everyone that walks up to talk about my car asks if the T is for turbo :). When I was a kid I thought all 911s were turbos.

Turbocharging is basically cheap, free HP. The 930 is a great concept, but Porsche went way over the top when they designed the original. I sometimes think the factory engineers go for perfection when they make a quantum leap forward. Do you really need an intercooler? It's still "free HP" without an intercooler. Turbos are a dog without boost, because their CR is so low. (CR is directly proportional to HP) Build it with a higher CR, and reduce the boost, and it becomes a more broad ranged unit.

I think when I get around to the new engine, I'll go for a scaled down version. Part of the turbo problems, besides $$$$, is that the engine needs to basically be built to support the turbo. Can't just hang a turbo on like an ornament on a Christmas tree.

That's one beauty of the Proto Stage 1. It is designed for US spec CR so you don't have to modify the internal engine to lower CR. It is, more or less, bolt on, so you can always return the engine to stock if you save the parts, although I don't know why you'd want to do that except maybe for resale.

Once you've driven it, you (or a prospective buyer) would never want to go back.

Not an apples to apples comparison but in heavy trucks and or tractors/equipment Turbo charged motors are just a given anymore.

Very reliable horsepower / torque with very little maintenance.

From memory, Cummins diesels went from normal aspiration back in the late 60's to 70's @ around 160 to 220 HP to adding turbos with no coolers @ around 260 to 335 HP.

Then in the late 70's inter-coolers were added to net around 350 HP. The 350's went to 400's through the 80's with just suttle changes.

Then in the 90's through today with eletronics and Air to air cooling some of the biggest power is over 600.
At around 550/600 HP the drive-train has to size up to handle the power. So this much HP starts to get expensive at these levels.
I'm not positive about the earliest motors from Cummins but from the late 70's foward they are all the same displacement, 855 C.I.
and run up to about 2100 RPM's

Just another perspective on Turbo power :)

Big trucks all run, or did anyway, turbos and superchargers. Diesels love it, since they need 18 or 20:1 just to fire.

Turbocharging is a sophisticated engine addition, which delivers heaps of power in a crude fashion.

Its is known that 3.0 and 3.2 motors have lasted over a ridiculous amount of miles. Whats the life expentancy (in general) of a 3.3 turbo engine ? Any stats on 91/92 3.3, 94 3.6 turbo ? Maybe even perhaps 1 96 TT ?

I’ll argue the point counter to Formerly.

A turbocharged 911 on the track requires even more finesse in the turns than NA. This is only slightly due to any turbo-lag. Most turbo racers have two smaller turbochargers rather than one large one. This adds to the responsiveness. Additionally the engine spends most of the time between 5000 and 8300 RPM, again increasing the responsiveness and linearity. It is not “point-and-shoot” driving but very drivable with the throttle.

The difficulty is applying all that power to the road. There needs to be serious amount of grip from huge tires (on 15x19 rear wheels) and aerodynamic forces. Some of this compromises the handling. Hot and sticky Goodyear slicks with a “spool” in place of a deferential leave only a small window of good handling in corners and is above the 98% performance range. Drop below that and most develop a severe “push.”

On track a 300 HP NA 911 with realistic tires is a dream to drive. It also is drivable with the throttle. The benefit (mostly from skinny tires) is there is a wider window of proper handling.

Performance on the street is a whole ‘nother animal. The difficulty with a turbo is most aren’t prepared for the sudden rush of power when having gone to full throttle and the engine is at low revs and the single large turbo isn’t already at full speed. Just about the time you get full power you want to be modulating the throttle. Occasionally that all occurs too suddenly for comfort and some bad things can happen. Many of the unique features we find in a street 930 are to prevent the driver from killing himself.

A NA 911 can more easily modulate the power and is relatively linear with the throttle position. Some well designed systems are particularly good response (MFI, EFI, V-Ram.)

Current turbos have a unique ability to modulate the performance depending on use, fuel octane quality, and temperature. Far from crude and not easily done with a NA engine.

Best,
Grady

HP for our purposes, in its most basic form, is all about "how much charge can you pack into the cylinder?", followed by "how hard can you push that piston down?". All attempts to increase HP are derived from this basic premise, Whether its NA, turbo, supercharged, that is the botom line.

There is only a finite amount of power which can be extracted from the internal combustion piston driven platform. There are ways to deliver less of a heap in a less crude fashion. However, Dr. Island's statement pretty much sums up turbocharging as we know it.

Pat