At least thats what I keep hearing from turbo guys,lol. Someone on another forum said the backpressure dampens the piston or some chit. Is that the correct answer???? I'm having a hard time figuring that one out.

 

I'm a newbie to turbos and I'll throw out my theory. Not saying it's right or wrong. LOL

Nitrous, in my opinion, hits harder on the pistons instantly.
Superchargers are harder on cranks due to the belt/chain setup. I know a former SSO driver that broke three cranks with an F1R.
Turbos work off of exhaust and seem to be a bit softer on most parts with the proper tune. Sure they can break things, but I feel they don't punish a motor quite as hard as the others.

Just my opinion.

 

A 500Hp turbo setup requires the engine to put out 500Hp. A 500Hp supercharger setup requires the engine to put out 500Hp+ what ever it takes to drive the supercharger. If the engine was 250Hp naturally asperated it could take 70Hp to drive the supercharger meaning the engine is having to actually put out 570Hp.

I don't see nitrous being much harder on an engine. It is easy to mess up the tune and destroy an engine but under the right circumstances I don't see it being significantly different.

 

Iwould say that is the small of it.

 

I dunno...I hear of guys making 700-900 hp with guys running stock 350's and chit. I see a lot of 2000+ hp motors that are turbo's, not so many blown pump gas deals. I realize turbos are free power, just trying to figure out why they kick azz.... all I want is 1000+ out of my 557.

 

I've "heard" nitrous is harder on a motor/drivetrain because its more of an instant shock of horsepower rather than a relatively slower addition of horsepower while the turbos spool... Now leaving on a 2 step at 15psi of boost seems like it would be hard on anything. I'm more talking about rolling into in a street race.

And turbos aren't completely free hp. The exh backpressure does cause pumping losses. If you had the same temp/psi of air being pumped into a motor thru some other means not driven by the engine, it would make more hp than a turbo would.

 

Nitrous is adding a chemical to get more power, most high power nitrous motors have pretty high compression too.I'd assume the chemically added oxygen alters the flame a little, possibly making it a faster flame than something from a blower/turbo... (but that's a topic for the advanced tech guys to talk about I'm just theorizing outa my arse).

Superchargers and turbos both add power the same way, by compressing the incoming air. The supercharger just puts a hard load on the snout of the crank whereas the turbo puts the load relatively equally on each cylinder via exhaust pressure.

 

The higher exhaust pressure of a turbo also cushions the rods at higher RPMs. Helps remove some of the tension load.

 

I think thats pretty much what the guy on my boating forum was trying to say. I want to twin turbo my 557 so bad I can taste it.lol

 

your right, from what i keep hearing is 2-steps make small little violent explosions that build boost quick but can wear down turbines quickly FYI

 

I remember reading recently (might have even been in the turbo bible here) that the force of the piston fighting the backpressure on the exhaust stroke is more or less negated by the force of the boost forcing another piston down in the intake stroke. Sure, an N/A motor will have less backpressure, but it also will have a vacuum in the cylinders on the intake stroke.

Free power... I don't know if I'd go that far, but it's far more efficient.

 

I've have seen were John Force say's his 5000hp motor takes 800hp to 900hp just to spin the supercharger.

 

Agreed. Never thought of that. But most turbo systems have higher back pressure than boost pressure. So it still is using energy on the exh stroke. But if your ratio is close to 1 to 1 exh to boost than your right. Its probably negligible.

 

Corky bells book Maximum boost explains exactly why turbos are easier on the bottom end. Dont ask me though I just log it in my brain as turbos r the best over and over. Hot rod mag says Turbos have the most effiecent compressor as well. Again TURBOS RULE :rock: :rock:

 

Cylinder pressure/time is the biggie. Nitrous engine cylinder pressure is much higher in the initial burn, but fades out quickly. Turbos, and superchargers for that matter, build cylinder pressure over a long period of time therefore cushioning the hard parts. In the end a 600hp nitrous motor and a 600hp boosted motor are doing the same amount of work, but the boosted motors are producing the torque over a longer period of time (albeit we are talking milliseconds vs. milliseconds) and don't shock the bottom end as much. Naturally aspirated is hard on parts mainly because when compared strictly on power they will need to spin to a higher rpm than a similar power boosted or nitrous engine.

RPM kills engines much more than power ever will, and the simple equation for that everyone should know, E = mc^2. A piston's energy (E) goes up in multiples of the mass of itself, but the square of its speed. Put in a piston twice as heavy as a control and the stress on the rod on the return stroke is doubled, but if you take the control piston and put it in an engine spinning twice as fast then the rod stress has squared.

As far as free power, nothing in life is free. A turbo with a 1:1 TIP/boost ratio is as close as it will get, but internal combustion engines are heat pumps and turbos build (and waste) some serious heat. A crank is already under enough twisting stress just having to transfer the torque from the rod journal into the transmission to not have the extra stress of driving a supercharger. On big roots blowers the front main bearings and crank snout really take a beating, and that's why aftermarket cranks will offer beefed up snouts just for handling the extra load driving a big blower produces.

With all this said, I love turbos, and the only real disadvantage to them is trying to get all of that hot piping snaked throughout the engine bay without melting everything in sight. At least with a blower you just buy or build a bigass set of headers and the exhaust heat is pretty much out of the engine compartment from right there. Yes, turbos do RULE.

 

Well to throw another spin on things, Nitrous motors with progressive controllers don't have as much initial shock on the internals, then they build over the track kinda like a supercharger/turbo setup.