Swagger93

"Go with the turbo....You know what car company was the first to put a turbo on a mass produced.......and what year.....?"

Actually Saab in '75 if i remember correctly.

Lead Foot 944

Thought it was Porsche in 76 or 74...on the 911 turbo....?

What about first mass produced to have airbags..?


DAmian

Porsche-O-Phile

I've always preferred the solution of the turbocharger over the supercharger from an engineering standpoint - a supercharger takes a tremendous amount of power away from the engine in order to work, whereas a turbo utilizes something that would be wasted anyway (the momentum of the exhaust air) to beneficial effect. True there is some loss due to the exhaust gas having to spin the turbine in a turbo, but that would be an inherent factor with ANY additional device.

If you're doing a lot of quick "spool up / spool down" operations, such as with aggressive track cornering, a supercharger would probably be a better bet. For overall maximum power generation I'd say go with a turbo - less to go wrong. Unless you lose oil to it, a turbo is pretty much bulletproof and even if you do, in most cases you'd just get NA (or very slightly less than NA) performance. I'd be more confident in a turbo being able to "run all day" on a long trip somewhere than a supercharger, even given the increased temperatures.

Swagger93

Hehehe Damian-- im not positive which was first, but i think they were both in 75 or 76, at almost the exact same time.

The fact that a supercharger drags power is inconsequential at this level of output. If you want another 40-50 hp, its not going to matter since a supercharger and turbocharger can both deliver the same net gain.

And i beg to differ on the "bulletproof" comment on a turbo. Ever have a wastegate stick? Lose coolant to a water cooled turbo? Bake oil in a turbo and trash the bearing? Vac line fly off the BOV at high boost and surge the compressor to death upon throttle closure? Turbos are dependent on more external systems to keep them operating properly, and some of those above situations have occured directly to me or to people i know. If a turbo seizes and you leave it on a motor and run the motor you run the risk of spewing the shaft or impeller blades because of the immense heat; this could damage the motor.

Superchargers arn't extremely reliable either. They snap belts, can do the same internal engine damage as a turbo (burned pistons/blown headgasket) and such. Mounts can break for them since they require so much torque to drive.

I personally prefer turbochargers as well so I don't know why I'm arguing for the side of the supercharger. I guess its just a friendly rebuttal to Porsche-o-phile's post. Gotta keep this one going anyways.

The smartest idea is to sell your N/A and get a 951. Is that the idea that will provide the most fulfillment? NO! I am envious of all you 951 owners? YES! hehehehe

Porsche-O-Phile

The "coking" problem you mention is addressed on the 951 by the coolant circulator; as a general good practice I would recommend running synthetic oil and doing a one to two minute "cooldown" at idle before shutting down. I know that's impractical as heck sometimes, but it does help to keep the oil that's sitting in the turbo from cooking and congealing. Of course, an oil circulator would address this problem too. . .

I guess it's six of one - half a dozen of the other. I guess it's whatever you're comfortable with. Anyway, welcome to the FI world; hopefully I'll have my car done soon and be turbo-ing along with the rest of you. . .

Bhj0887

I've never had a supercharged car, but am really thinking of supercharging my 944. It's much simpler to install and has ist's advantages. Mainly the flat torque curve.

If your looking for the most power then turbo is hands down your best bet. If your looking for instantaneous extra power the supercharger wins.

You have to look at in a different point of view.......
You have 300 rwhp in your 944, you have turbos this car.
You have 300 rwhp in your 944, this one's SC'ed.

Now who cares, whether its a turbo or an SC, they both make the same HP. The SC probabaly makes a better Torque curve.

Now, put the cars in a drag strip (I know there not meant for it but it has to go in my little explanatuion). Which do you think would win....I'd put money on the SC'ed car.

Now throw em at a track who do yout think would have the quicker times, with the same driver. I go with the SC again.

Now just put the cars on the street fr normal everyday driving, in this case the turbo could win, for getting better fuel ecomony if you don't get into boost that often. And probably a much more subtle drive through traffic.

Everyone in saying SC's are inneffiecent, technically they are in some ways, but in others they can be better than turbos. And if your goal is to reach, say, 300 hp, and you hit that goal with a supercharger then who care's if you have rob power to get power.


BTW, any kind of FI is going to create more stress on the engine and risk the reliabiltily of the engine.

bader$

IIRC the porsche uses variable lifters to constantly vary lift and duration not a rotating camshaft.

bader$

GM had it as an option in the late 60"s but as a standard option i think it was Mercedes

roadrunner

Not true... The Porsche lifters don't constantly vary the lift, they operate in one of two positions to follow two different camshaft profiles, exactly the same function as the VTEC rocker arms in a Honda engine...

Are you also saying Porsche doesn't use a camshaft?

bader$

No. My understanding is that they use a fixed grind camshaft with electronically controlled lifters that uses oil pressure to vary lift and duration. This way they can constantly vary the valve timing.

What I meant in the reference to the camshaft is that most utilize some way to rotate the cam position to vary cam timing, which is an on/off type system. The vtec does though have a split cam love which varies duration, but still is an on off system.

bader$

I am wrong. It uses both. Variable cam timing (shaft rotates its position) , lift and duration accomplished by the cam and two stage lifters

http://content2.us.porsche.com/prod/...evariocam_plus

roadrunner

It still uses only two cam profiles, which is where the lift is determined. The lifters cannot change the timing or lift with respect to those profiles. Whether the camshaft angle changes with respect to the crank does not change the profile of the cam lobes, of which there are only two.

It should be noted that the distinctly different systems of the original VarioCam and VTEC have been combined by both companies into VarioCam Plus and i-VTEC, and they perform essentially the same function. At least VTEC was revolutionary, VarioCam had already been done in one fashion or another in other cars, and usually had a less pronounced increase in power production. That doesn't mean that Porsche doesn't produce bad engines, but it should burst the bubble that they are all conquering and superior in engineering, and that Japanese engine technology is worthless. I still say that if the Japanese can produce a powerful engine of smaller displacement, make it last at least as long as anything any other countries' manufacturers can, and make it cheaper, then that IS a sign of superior engineering.

Just remember that Civics can be had with twin cam designs that last over 300K miles, but Porsche 944S and 944S2 engines had a design flaw that could end up cracking the head and costing several thousand dollars to repair -- don't forget to reach for your ankles as you pull out your wallet...

roadrunner

ummm... that's about 10 years after the following:

1962 Oldsmobile Jetfire Turbo with a 215 CID V-8, then followed a month later by the 1962 Chevrolet Corvair Monza Spyder Turbo with a 145 CID H-6.

bader$

I think that there are a lot of manufacturers that build some note worthy engines/powertrains. I think that they all copy one another and make improvements as they go. I have seen many similar component on the various makes I have worked on over the years. I am impressed by the balance and handling of the 944 series. Hard to match for the times they were built until you consider how much they cost new. The original list for my 88 944S was 38k. Which was twice as much as the cars they competed with on them market then. They are an exceptional value now though.

Also getting back to the original topic. I agree with many that for all out performance the turbo route is best. But for my own daily use I would rather have a s/c on My S for low end torque, which is where it is seriously lacking.

Lead Foot 944

Yeah Mercedes was the first for a standard with the airbags in their cars...But still no definate on the first mass produced Turbo car...

DAmian