Contour Enthusiasts Group Archives Forums Modifications Forced Induction price for power???

Vortech comes with 3yr warranty+ease of installation at your local vortech distributor, Turbo installation might be a pain unless you're near Terry, Chris, or in AZ where SF is. . .

Originally posted by RTStabler51:

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Demon, how is the turbo not rpm dependent??

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A turbo is not rpm dependant; it is exhaust energy dependant. The rpm, and consequently boost pressure and flow of the turbo are not controlled by the rpm of the engine, but by the exhaust energy coming out of the engine. Whereas a supercharger is entirely rpm dependant because it is mechanically tied to the crank.

Tommy, I thought you meant if the turbo had a quaife as well.

right, but does the exhuast flow (higher rpm = more exhuast flow) make it rpm dependent? I know little about turbos and looking to get informed Rare :-)

Originally posted by Rara:

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Originally posted by RTStabler51:

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Demon, how is the turbo not rpm dependent??

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A turbo is not rpm dependant; it is exhaust energy dependant. The rpm, and consequently boost pressure and flow of the turbo are not controlled by the rpm of the engine, but by the exhaust energy coming out of the engine. Whereas a supercharger is entirely rpm dependant because it is mechanically tied to the crank.

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Yes and no.
The turbo is rpm dependent in that you must have a motor that spins/runs to make exhaust, but that is about it. Exhaust volume/cylinder does not change a whole lot as rpm goes up, but the total volume/time does go up as rpm goes up since there are more strokes at higher rpm.
That is irrelevant in the case of the turbo's dependency upon it.
Let me ask you this, if the throttle is full open and the engine is at 1000 rpm or at 7000 rpm: Is there a significant diference in the exhaust volume that one cylinder can produce at either rpm if time is not a factor?

Think of it this way...you can size the turbo to provide boost at a low rpm, and then as the rpm climbs you can regulate the portion of the air that is put into the engine with a wastegate. This is why turbos are called 'free' power.

I don't want this to sound condescending, but if you understand what Rara is talking about then you will understand why aside from cost, the turbo is a far superior option to the centrifugal force supercharger. It translates in a torque boost all throughout the usable rpm range of the motor and not just at the top of the rpm range as with the vortech.
On the other hand, any boost is better than no boost!

warmonger

You can hash back and forth which is better for any given application all year. You're still left with several basics of modding.

Price: Vortech kit comes in cheaper initially, but the SF turbo system has quite a bit more parts included in that initial price. Advantage: Depends on your pocket book.

Performance: The turbo kicked the crap out of the Vortech on initial numbers. But yet again, add on those extra bits like headers, cooler boost, and tuning ability to the Vortech and see what you get. Advantage: Depends on your pocket book.

Reliability: The Vortech had some stumbles out of the gate, but picked up some points with the redesigned jack shaft and mentioning putting a loop in the oil feed line to save the oil seals. The turbo just started making waves and needs to settle in before I make any sort of move. Advantage: Vortech until the turbo is at least a year old in my eyes.

Upgrade availability: Put a smaller pulley on the Vortech to bring the boost on sooner for more low RPM torque and HP. Still at the factory 9psi ratings unless you change out the BOV. Add a water/air cooler. Headers. About all that's left to upgrade on the turbo system is the boost setting and/or swapping out to a larger turbo. Advantage: neither.

It's all about trade offs when it comes to modding. Quite frankly I won't be happy until I've had both and been able to break both before I make any decision. What ever puts down the best numbers in my car with me driving is what I'll stick with.

Well put Bnoon

However we do need to see a direct juxstaposition of the two dyno plots of 2 stock for stock cars of the same Bread meaning "SVT vs. SVT" or whatever, before we come come to any conclusion!!!! Also the same conditions and remember no Ice in the intercooler!!!

Rara: I challange you to rev your turbo'ed engine to 2000rpms and look where the boost gauge is and then tell me the turbo is not RPM dependent!!!!!

Given the turbo can be more efficent if done right and again I am not dissing the turbo, I whould like to have one myself !!!!!!

Thanks Warmonger, that makes sense :-)

On an SVT, EITHER system has been shown to make near 300 FWHP. So, EITHER system is then making just about as much power as you want to make with stock internals...something to consider. If you are upgrading rods/pistons (but most are not) that is another story...

Turbo makes much more low end tourque..is this good or bad?


Basically..
Will the rods hold over 300 FWHP for long???
Can you get 300lb/ft+ to the ground in a FWD car without violent wheelhop???
Will ANY (modified or not) MTX-75 survive a 300+lb/ft with a clutch drop???

Like a end of season cliffhanger...
When someone figures out these 3 answers, you will know what to buy.

Originally posted by TommyBoy:

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Rara: I challange you to rev your turbo'ed engine to 2000rpms and look where the boost gauge is and then tell me the turbo is not RPM dependent!!!!!

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To sum up what warmonger said, how do you get to 2000rpms? Do you mash the gas pedal or do you go up to that point as slow as you can? That's what will make all the differance, not that fact that you're at a certain RPM.