still torn between super vs turbo

[SRV BOY]

Ok I found out all the facts about a turbo and a supercharger, I have came to some kind of conclusion that a turbo will provide much better results in terms of performance for my car but it will require a lot of changes towards my engine such fuel management, pistons, intercooler and so on and so fourth. I also understand that I will significantly be reducing the life of my motor. So if I were to choose the supercharger path, will I atleast get 3-4 years of engine life out of this?? What I was told or a reply that I got if i got a turbo put on my car, lets say 7-8psi my engine would only last for 1-2 years?? Please respond if you can give me any advice thanks!

[Neutrino]

Originally Posted by SRV BOY

Ok I found out all the facts about a turbo and a supercharger, I have came to some kind of conclusion that a turbo will provide much better results in terms of performance for my car but it will require a lot of changes towards my engine such fuel management, pistons, intercooler and so on and so fourth. I also understand that I will significantly be reducing the life of my motor. So if I were to choose the supercharger path, will I atleast get 3-4 years of engine life out of this?? What I was told or a reply that I got if i got a turbo put on my car, lets say 7-8psi my engine would only last for 1-2 years?? Please respond if you can give me any advice thanks!

the changes towards your fuel management, internals etc will be determined on how much air you want to cram in regardless of the means

the same goes for the engine life

basically a supercharged engine will not require less modifications(besides the install of the kit itself) or will make you engine last longer than a turbo pushing the same amount of airflow

[Doubletap]

Man I just read that thread posted by neutrino and that was some heavy stuff. I feel like the smartest person alive. Its too bad we can't make that required reading on this forum. It sure might stop a bunch of numb nuts from asking lame questions. Except the the ones who are too dumb to understand what it says anyway. But they're more fun to laugh at anyway.

Neutrino rules

DoubleTap

[killah_xft]

either setup will decrease engine life to an extent... but it's how you go around doing the forcing of air into the engine that determines the life of the engine... Turbos are good for higher end performance by elevating the top end power of your car.. while a SC will elevate the entire powerband of your vehicle, while the Turbo has no limits to how fast (up to 19,000 RPMS or more for most turbos) it can pump air, SC's are limited by how big of a pully they are running on the SC itself.

[Neutrino]

Originally Posted by Doubletap

Man I just read that thread posted by neutrino and that was some heavy stuff. I feel like the smartest person alive. Its too bad we can't make that required reading on this forum. It sure might stop a bunch of numb nuts from asking lame questions. Except the the ones who are too dumb to understand what it says anyway. But they're more fun to laugh at anyway.

Neutrino rules

DoubleTap

Glad you liked the articles.

Originally Posted by killah_xft

Turbos are good for higher end performance by elevating the top end power of your car.. while a SC will elevate the entire powerband of your vehicle,

not necesarily, here is a quote from the turbo vs super article:

Finally, turbos run proportional to demand. What I’m getting at is that compressor speed is dependent on airflow, which comes from two main variables: engine rpm and throttle position, if you will. Now, a belt-driven blower car’s compressor speed is dependent on only one variable: rpm.

as you can see as long as you put a large demand on the engine(read: put the pedal to the metal) you'll get boost down low(as long as you don't have some ridiculously laggy turbo) and a fat power band

you should try driving an srt4, if you push them even at low rpm they feel like a v8

[killah_xft]

well nutrino I was putting it in laymans terms for those not well aquainted with turbos.. I know turbos run proportional to the airflow produced by exhaust, and throttle position (demand). turbos do have their limits.. SC's depend on engine RPM's yes... but aside from the dependancy on RPM's they basically do not modify the powerband of the car (change of relation from HP/RPM's) the SC basically takes the powerband before install, and moves it north (higher) than it was before the install. Including lower end power, and top end... while a turbo will change the powerband. powerband will be the same as before the install until enough RPM's are made in the exhaust turbine to drive the intake turbine fast enough to produce boost. then the powerband will drive skyward as demand increases beyond initial boost.

[Neutrino]

Originally Posted by killah_xft

well nutrino I was putting it in laymans terms for those not well aquainted with turbos.. I know turbos run proportional to the airflow produced by exhaust, and throttle position (demand). turbos do have their limits.. SC's depend on engine RPM's yes... but aside from the dependancy on RPM's they basically do not modify the powerband of the car (change of relation from HP/RPM's) the SC basically takes the powerband before install, and moves it north (higher) than it was before the install. Including lower end power, and top end... while a turbo will change the powerband. powerband will be the same as before the install until enough RPM's are made in the exhaust turbine to drive the intake turbine fast enough to produce boost. then the powerband will drive skyward as demand increases beyond initial boost.

but that is what makes the turbos so much better. In a way you get a dynamic powerband that adjust itself to the demand you put on the engine. since they run off exaust gasses the turbo will basically "know" what you want from it and will deliver

on the other hand a supercharger has no ideea what you intend to do and will boost blindly

bottom line a turbo can get a much better powerband than a supercharger and not just top end

[SRV BOY]

Thanks for all the replies, but with a compression ratio of 10:0:1 especially with an h22a engine, I've read a lot of sites where people have blown the motors and these motors are not the most popular to turbo.

[Neutrino]

Originally Posted by SRV BOY

Thanks for all the replies, but with a compression ratio of 10:0:1 especially with an h22a engine, I've read a lot of sites where people have blown the motors and these motors are not the most popular to turbo.

well as you said 10:0 compression ratio is quite high for forced induction, plus fron what i hear the stock h22a rods are quite weak

[duplox]

SC's depend on engine RPM's yes... but aside from the dependancy on RPM's they basically do not modify the powerband of the car (change of relation from HP/RPM's) the SC basically takes the powerband before install, and moves it north (higher) than it was before the install. Including lower end power, and top end...

only if you're talking about a positive displacement blower. centrifugal types like your vortechs and paxtons do not. just like turbo compressors(since they're essentially the same thing) they have certain rpm ranges at which they're effective. At low RPMs they won't produce any boost either. Turbos have the advantage of being able to alter the ammount of energy they use via a wastegate. If full boost hasnt been achieved, the turbo will use all of the exhaust's energy that it can until it does, then it'll bypass the extra. This gives you a wide flat powerband since the engine sees the same boost pressure for a long time(if you sized your turbo right). Centrifugal supercharger's pressures vary throughout the rpm range, which makes it resemble a stock engine's powerband, but it is steeper as boost increases. Its like a stock powerband that was sort of stretched up and down. Positive displacement blowers like roots, lysholm/screw, vane, or wankel/rotary have more of a stock appearance to they're powerband. Piston type as well, but not very popular for cars. Basically, centrifugal superchargers rely on achieving a certain compressor wheel speed to accellerate air enough to create pressure. A positive displacement type simply says: "well, i need x ammount of air per engine revolution to create x intake manifold pressure" and so each revolution the supercharger delivers that much air. Positive displacent basically increase the displacement of the engine.

Oh and one more thing, turbos are dependant on 3 things... exhaust volume, load, and EGT... Although load is just translated into EGT. so i guess two things, exhaust volume and EGT.

[duplox]

P.S. On the subject of compressor RPMs, I'd be interested to see someone develop a supercharger with an CVT(continuously variable transmission, as was in saturn's vue up until this year... obviously much smaller though!). that way the IVT could be at its lowest ratio whenever not at WOT, so you'll get no boost and no power loss to the supercharger(since it'd be spinning so verrrry slow). then when you floor it, the IVT will decrease its drive ratio, and overdrive the supercharger until you hit your desired boost level. It could then continue to vary the supercharger's rpm throughout the rpm range to hold the desired boost level. Sort of a supercharger that mimics a turbo, stealing the advantage of a wide flat powerband, and even extending it by eliminating lag(well almost, depends on how fast you can get the CVT to react). Still does have that nasty parasitic drag though.