Why Are Turbos Unwanted

[jryerson]

Turbos appeal to a different driver, typically a performance speed oriented type. I had 2 other NA 911s a S and SC and the Turbos are a totally different car from the power, you can dump the clutch and fry your tires at will from 1st to 2nd gear, something you don't usually see in a 911 going down the street burning rubber.

I have hit corners hard on full boost at 4500 rpm and its very controllable, going into a corner under boost then hitting full boost is more of a challenge.

Whats funny is many people see my Turbo who don't know the cars and actually think their new SUV is faster such as going to an on ramp and so forth, when I punch it you can see the suprised look on their face as I pull away from them before they know it. Usually they are looking at their cars dash for some reason watching their instruments to see if something is wrong with their vehicle and wonder how an old Porsche just left them totally in the dust.

[sprbxr]

I have owned turbos and non-turbos. I currently track a 91 C2 turbo. It takes finesse to drive any type of 911 well. The guy that said you need to turn, then accelarate in a turbo is mistaken. When I am on the track my car doesn't even feel like it has a turbo. Maybe I am just used to the power. One thing I do know is I am almost always on boost (1 bar), even while cornering. The key is timing. Get on the gas early in slow corners so you get full boost at the right moment. A very satisfying experience when done properly. The lag in the C2T is minimal compared to my 930. I think alot of that is due to better gearing and better exhaust.

After driving turbo Porsches, the normally aspirated ones seem kind of boring. Everyone should be lucky enough to experience the rush of accelaration only a turbo can give you. You won't be disappointed.

[Craig 930 RS]

It is addicting. I drove the 930 for about 2 days before buying it........it is amazing.

[89911]

One of the issues I see with turbos is that the ones that own them are definitely into power and they just don't know when to leave well enough alone. All power, no matter how much becomes, second nature after a while. You get use to it. With a NA car, the improvements are minor and expensive, but generally do not harm the engine and may actually improve reliability. With turbos, the cost for dramatic increases of power are relatively inexpensive, but the possible damage to the engine is considerable. All it takes is another 930 with larger intercoolers and higher boost passing you on the track for you to consider these options. It's a power addiction that keeps aching for another hit. Just say no !

[fastpat]

The current RS engine is 3.6 liters, 430-460 horsepower @ 8200 rpm naturally aspirated. These cars are competitive at Daytona and Le Mans.

When I chose a car I intentionally avoided turbo models, not from a cost standpoint, but from avoiding needless complexity.

One of the best things a turbo owner could do is have an engine driven supercharger added to replace the turbo. Responsiveness would dramatically improve, and engine temps would likely be lower.

For example, an interesting car built in Southern California last year is a BMW Z8 that started out with a 5 liter 400 horsepower engine, with a belt driven supercharger and custom manifold with intercooling it cranks out 750 horsepower, not proof of the concept, but pretty interesting nevertheless.

[YermanCars]

Its all prefrence, I myself love turbos, of course my car is more of a drag/ hot rod car more than a track car, but I love boost

[derickc]

Originally posted by fastpat


One of the best things a turbo owner could do is have an engine driven supercharger added to replace the turbo. Responsiveness would dramatically improve, and engine temps would likely be lower.

This is a common misconception about turbos that would *seem* to make sense because a turbo uses hot exhaust to create boost whereas a supercharger doesn't. The reality is that the heat created by either a supercharger or a turbo is a function of compressing the air (when you compress air it gets hot) and has nothing to do with the hot exhaust.

There are two basic types of superchargers: screw type (imagine two large, long gears rubbing against each other to compress air) and centrifugal (basically the "cold" or compressor wheel side of a turbo). Any gas compressing device can be measured on an efficency scale. The efficiency scale measures the amount of heat added to the air as it is compressed relative to the ideal gas law. When you compress any gas it is going to get hotter by some minimum amount (the ideal) and the efficiency of a compressor is a function of how much MORE it heats up the gas than the ideal.

A screw type SC heats the air a LOT more than a turbo and is basically very inefficient. You don't want this device unless you want lots of low-end torque (below 2000 RPMs) and very little additional horsepower.

A centrifugal SC is just a belt-driven turbo. It compresses the air in exactly the same manner as a turbo, but it has a huge flaw - it's spool characteristics are a direct function of engine speed. Once a turbo engine produces enough exhaust velocity to spool the turbo to maximum boost (usually 2500 to 3000 RPMs), the extra exhaust velocity past that point is bled to the atmosphere via the wastegate. So a turbo will produce full boost from about 3k to redline. A centrifugal SC compresses the air as a function of engine speed because it is driven from a belt via the crankshaft. By definition, max boost is set at redline. If it were set below redline, you would overboost beyond that RPM. A centrifugal blower produces boost as a square function of rotational RPM of the blower. So a car that produces 16 psi of boost at 6k RPM will only produce 1/4 of that or 4psi of boost at 3k RPM. The centrifugal SC has 4psi of boost at 3k and the turbo has 16 psi at 3K. Which would you rather have?

The centrifugal SC has a *fake* torque curve. The only reason it feels linear is because it comes on in such a slow, pathetic manner.

A turbo has a much broader, deeper torque curve than a centrifugal SC, and it produces boost with a lot less heat than a screw-type SC (less heat equals more power given an equivalent level of boost). There isn't a supercharger made that has any characteristics that are more favorable than a turbo.

[yasir]

Originally posted by fastpat
The current RS engine is 3.6 liters, 430-460 horsepower @ 8200 rpm naturally aspirated.

So you think this NA engine is cheap my guess would be atleast 30-40 grand if not more !

[nostatic]

Originally posted by jryerson
Turbos appeal to a different driver, typically a performance speed oriented type.

as in streetlight drags against suvs?

[fastpat]

Originally posted by yasir
So you think this NA engine is cheap my guess would be atleast 30-40 grand if not more !

More.

The point was that NA engines can be quite challenging and potent. Want to price a new turbo engine from Porsche?

[Shuie]

Im sure a capable NA motor will cost about the same on a tight, technical, and twisty track as a big nasty turbo would on a longer and straighter track. None of this stuff is cheap.

[350HP930]

LOL, I always enjoy hearing all the excuses the NA people will make to explain why they are better off without all that extra power a turbo would give them.

[patkeefe]

Derickc:
I got a bit lost after the first paragraph. I was under the impression the only difference between a supercharger and turbocharger is the compressor drive mechanism, and that they both obey the laws of thermodynamics.
Pat

[fastpat]

Originally posted by 350HP930
LOL, I always enjoy hearing all the excuses the NA people will make to explain why they are better off without all that extra power a turbo would give them.

That's the point, the turbo doesn't give extra power, it's a method of increasing displacement artificially. Rdane's new ride is 3.6 liters and 280 RWHP, more than the turbo you started with, with significantly less weight and complexity. Increasing displacement is nearly always productive, in the power department, whether by forced induction or an actual increase in cubes.

It's personal choice, like paint and interior colors.

[ficke]

I want a 930!! but for different reason than an early 911, they are different cars and offer a diff. drive.
930 have four speed trans. because they have more torque and a broad enough power band that Porsche felt a 5-speed was unneeded. Should that not answer some ??'s
When NA cars our hot rodded 930 tie-rod ends, CV's, trailing arms,brakes etc. etc. our used At some point I wonder also, why not just buy the 930?
My nimble early 'S' could never be replaced by a heavy brute 930. They or so different Porsche even call's them different ,911 ,930. I want both!! I do not want to turn my 911 into a 930 and a 930 can not offer the same pleasure as my 911. Drive a good example of both and depending on who you are or the mode you are in will determine the one you like more. Some times more HP does not equal more pleasure, like more alcohol does not always make a better wine.
A good track car is not what I want to drive on the street. I usually do not like to track my street cars, of course I do
The people who really should answer the originally question are the ones who put twice what a 930 cost into there 911 money is not the deciding factor for them.

[afterburn 549]

I think every one needs to read Max Boost by Corky Bell. This is a ez to understand and get rid of old rumors on turbos.gives some guidelines and how to stuff and some math!

[89911]

Originally posted by ficke

930 have four speed trans. because they have more torque and a broad enough power band that Porsche felt a 5-speed was unneeded. Should that not answer some ??'s

Why did they match a turbo in the 89 G50's 5 speed? I think the reason was they didn't feel a 5 speed 915 was up to the challenge and would rather sacrifice a gear for beefing up the other 4. Nobody in their right mind would prefer a 4 speed over a 5, or a 6 nowadays. I think the early turbo lag and 4 speed has some to do with early choices towards light, quick reving 911's. Turbos have improved dramatically, especially now.

[fastpat]

Originally posted by ficke
I want a 930!! but for different reason than an early 911, they are different cars and offer a diff. drive.
930 have four speed trans. because they have more torque and a broad enough power band that Porsche felt a 5-speed was unneeded. Should that not answer some ??'s
When NA cars our hot rodded 930 tie-rod ends, CV's, trailing arms,brakes etc. etc. our used At some point I wonder also, why not just buy the 930?
My nimble early 'S' could never be replaced by a heavy brute 930. They or so different Porsche even call's them different ,911 ,930. I want both!! I do not want to turn my 911 into a 930 and a 930 can not offer the same pleasure as my 911. Drive a good example of both and depending on who you are or the mode you are in will determine the one you like more. Some times more HP does not equal more pleasure, like more alcohol does not always make a better wine.
A good track car is not what I want to drive on the street. I usually do not like to track my street cars, of course I do
The people who really should answer the originally question are the ones who put twice what a 930 cost into there 911 money is not the deciding factor for them.

I think this is the best argument for a turbo that's been made in this thread so far.

[alwaysflat6s]

Well folks, I should just stay out of this but, as I am a 930 addict, as well as a n/a lover.. here is the answer.

Short answer: Money money money.

Second short answer: People don't really unstand them.

Third less short answer: They are the all time best Porsche ever built. If Porsche had only built that run of 500 930s to go racing [which almost happened], people would speak of 930s in hushed voices. NO one would pontificate about the 73RS as the all time greatest Porsche like they do. It is the very success of the 930 and long run of cars that has ruined the aura which would otherwise exist for them. Can you IMAGINE how people would sing their praises if they had only built 500 and turned 25% of them into race cars? [I reserve the right to pee all over the 73 RS as I own one.] 73 RS: Great driving, responsive, light, quick, pretty, somewhat rare. BUT any good early 911 that is well setup is just as great in its own way. It is all a matter of what part of the performance envelope you worship or have the ability to use. NOTHING Porshe has built since has the abilities of a GREAT 930. Ido include ALLof the good RWD puffers here. Even the GT2. Supreme driver's cars all. Remember, NOTHING comes close.

Long answer: You can buy an inexpensive turbo but, they are NOT inexpensive cars to own and operate! REALLY. Can you afford to maintain a 12 cyl Ferrari or a Lambo? If the answer is YES then you will be able to stand the brutal prices it costs to make them work the way they should and the much more expensive maintence costs.

Unfortunately, since they look just like a 911 with flares and wheels, people get sucked into buying them that cannot afford them. The reason a lot of them sell inexpensively is because the particular car has had somwhere between indiffernt to totally inept maintence. Many of them have horrible modifications by"mechancs" that have no business working on them. MOST Porsche mechanics do NOT understand how all the subsystems interact and do very poor repairs. The cars do not tolerate half ass workmanship that a you can get away with on a 911. This goes back to the early part of this where people who cannot afford to care for them can afford to purchase one.

3- Outside of poor maintence and dysmally inept owners, the biggest and theoritically the most troubling situation with 930s is people increase HP without increasing the ability of the engine to handle THERMAL STRESS [that's heat to us regular folks]. When that happens, as with the add on turbo kits, the engines run just great.. until they finally suffer from generating more HP than the pist/cyl were every designed for. That is when they are great fun to watch [as long as it is someone else's. Kinda like watching Kimi in his McL blow itself to bits with flying parts and fire all over. Thermal overload makes things break in a very big and expensive way.

The only way 930 owners get around this when they decide their rocket ship is still not fast enought is to tear it completley apart and enhance things. This means a nice 3.4 pist/cyl kit. Why, you ask? NOT because they are bigger, because they are designed to to get rid of heat MUCH better than stock 930 pist/cyls.. which again are much better and stronger than n/a pist/cyl [which again is why add on kits without upgrading pist/cyl are a very short sighted way of increasing hp]. Go to BA's book and look at his images of the 3.4 pist/cyl. See all those nice cooling fins? Now look at the stock 3.3 pist/cyl and you will notice they have far fewer. These DO make a difference.

Back to the main subject. It is not uncommon for hot rodders to blow well over $20k upgrading their 930 engines. That is JUST the engine guys! How about adding $12,5k for a Ruf 5 speed? Yea-needed. When they are doing this, they know the car is not going to be worth that much more. They are paying for the pleasure of making it terrific and reliable. They know the money will never be there at resale time. My very first 930 was in 1987. It was great. I wanted more-more-more. I added it up. I was going to spend $12k for improvements WITHOUT opening up the engine. This was just for the add on stuff. To make it really work I needed to port the heads, install better cams and then the piston/cylinders $$$$. They are VERY expensive to play with. When done right they are incredibly rewarding to use.

On the track: Frankly, most the tracks in the US are a waste of time. They need long straights to really open them up. It is fun to destroy someone running you in their...whatever. But it is insane bliss to take someone who thinks they are "racing" you in their mildly tweaked 930 and nail it at 140 or so and just watch them instantly disappear into a speck in your rear view mirror. [R.I.P. Riverside back straight.] If you are one of those guys who has stuffed a modded 3.6 in the arse end of your early 911, I agree it is fast, yea. BUT pally, is it REALLY fast? How badly do ya wanna find out what FAST is???!!! Quick-ok. Fast... ahaaaahahhahaha.

The turbo lag is really a problem of the past when these are correctly modified. A turbocharger is no more "artifical" than an "internal combustion" engine. Poorly designed [as with the K26] or badly integrated with the other engine parameters - they suck. Well designed, well chosen, and well integrated into the powerplant and they WORK. And with very little in the way of issues. The problem is simply their ability to overwhelm the rear tires and this does make them a handful if a driver is not well trained and understands how the car will react. A good one reacts pretty much the same as a n/a car but it has SO much more ooomph when you touch the throttle that it takes a LOT more skill and finess to use on the track. It also gives you wonderful options for burning up a set of rear tires!

With all of this I exclude the 933/996TT turbos. They are no fun. Too many electronics to save an inept driver. Yes, I am hard core but the only great cars to drive reward excellence in driving skill and PUNISH wankers. The new cars, as wonderful as they are, reward WANKERS! They can do all kinds of stupid things in them and their abs/yaw control/and all that crap- great it saves them from their ineptness when they don't know what they are doing. BUT, if you haven;'t figured it out by now, I despise this stuff for serious. Driving. In the wet, great. If it ALL can be turned off. Under normal driving it should ALWAYS be off.

If you can afford one, they are one of the most rewarding automotive icons ever driven. If you consider buying one, ONLY buy it after taking it to a well established mechanic who has a specific reputation for building/tuning TURBOS... not just some guy who is a Porsche mechanic and says they can fix turbos. I could tie up this entire list with tales of decent Porsche mechanics who are totally inept at working on 930s. Believe me, this includes dealers! Dealers no longer care about these old cars and they do not train their mechanics on them and their mechanics cannot plug their computers into them to figure out what is wrong. Many times they do what they do best... replace parts until the problems seems to go away. THO- nothing is as great as the SCal pilot who loveed his 930 but it seemed to be falling apart and ran horribly bad. The Factory dealership said "It's an old car. They all do that. Buy a new one." He took it to a REAL mechanic who understood 930s and in an afternoon the 930 was transformed into what he had always wanted.

So, if you like, go for it. BUT be careful. There is nothing as thrilling and rewarding as a good 930. There is nothing worse than a hacked up 930. AND, if you are still reading this.. And you think you might ...really... want a 930.. go out and buy some of the UK comparison books that cover the vintage 930s. Those guys drove them hard when they tested them and wrote about how they REALLY react to gas/brake/turn when the going gets serious. It was these writers that gave me a lot of knowlege [SCCA National racing also helped a bunch] and let me know what to expect when I drove them hard. I understand why many people see them as straight line machines. Most owners lack the skill/training to really use them. Most have NO clue how they will react. When they attempt this without a decent amount of skill and no training the result is usually a badly wrecked 930. I remember some astoundingly high precentage of new 930 owners who went off the road backwards in them back when they first came out. Many times in the first few hours of ownership. SOME RIDE. Get it right and heaven. Get it wrong and glorious burn in hell.

I have said way too much. Buried in all this are some words of genuine wisdom that may keep someone here from wasting a lot of money on a bad 930 or a poorly thought out modification. Anyone can benefit by reading the Brits and their testing of the older 930s and even the high preformance 911s of the 70s. Some great reading that is fun and will HELP educate you in how to DRIVE the "real" 911s.... before 911 became a marketing term

Now I will go away and hide. If I somehow offended someone 1/sorry 2/too bad -pick one but don't waste your time responding beacuse I try to never read a post if I have lectured like this and I have gone waaay past my limit. To those of you with 911 3.6 conversions- actually, I really like them. But its like comparing a P51 to an F16. Each has its optimum performance envelope. One is a lot more limited than the other. I have been lucky enough and crazy enough to own or build or just enjoy most of these better Porsches and that has given me specific opinions that I believe are valid and produced a series of performance results that are easily tested and repeatable. Scientific?

Godspeed all

[mmastro]

I don't understand the polarity of the Porsche owners on this issue.
I respect the early, NA light-weight 911's for what they are. And as the SC's and Carreras developed, they too were proven icons.
The original 930's were built to homologate the racing breed of that era. More of the street version 930's (at least in the US) were wrecked in their first week of ownership than any other import at that time. Many didn't know how to drive them and didn't know how to respect the 930's sudden power rush after 3200 RPM.

I have driven an early 912 (SWB) and that car is a BLAST to drive, but I would never compare it to my 930. It's just a different driving experience. I love the way my 930 feels on the track...turns 3, 5 and 9 at Willow's Big track come to mind. I'm just learning to finesse the car to decrease my times, and having enormous fun doing it!

Always looking for a early 70's 911 w/ MFI to buy and build for the track/street...I've heard that that's a whole different rush!...Would love to feel that!