blown

[hfh330i]

Trying to increase my automotive knowledge...I understand the basic differences between a turbo and supercharger and how they increase the power of the engine; however which form of forced induction is the more efficient use of energy? Why would one prefer one or the other? Just curious. :?:

[Plaz]

I'm no expert, but my understanding is that a supercharger will deliver a more even power curve, making the car feel like it just has a bigger engine, while a turbo is less parasitic and potentially more powerful, but suffers from a less linear curve... hence "turbo lag".

[FC]

I'm no expert, but my understanding is that a supercharger will deliver a more even power curve, making the car feel like it just has a bigger engine, while a turbo is less parasitic and potentially more powerful, but suffers from a less linear curve... hence "turbo lag".

I think that is correct. It also explains why MB sticks to superchargers given that they are a luxury maker and "God forbid" the customers registered significant lag in their cars. Meanwhile Prosche prefers turbos; more performance at the expense of some non-linear response early on.

[blee]

Trying to increase my automotive knowledge...I understand the basic differences between a turbo and supercharger and how they increase the power of the engine; however which form of forced induction is the more efficient use of energy? Why would one prefer one or the other? Just curious. :?:

It kind of depends on what you want, and how you want it. Both forms of forced induction (FI) can give you tremendous amount of extra power for a relatively modest amount of money, up to a point.

As Plaz said, turbos are powered from your exhaust and therefore do not cause direct parasitic loss of engine power. However, there is a certain lag time involved between opening up the throttle and experiencing the correlated boost. Because superchargers are typically belt driven, your engine loses some HP from spinning it up; of course, the gains from the supercharger outweight the parasitic loss by a significant amount. Centrifugal SC designs have a bit of lag, but supposedly provide smoother power output and more high-end power. Roots-style superchargers, which involve screw-like impellors, provide more low-end grunt but are known for being less efficient that centrifugal blowers and have somewhat less top-end power.

If you are careful with the type and install of an FI system, you can get a LOT of power (like 40% more) for a few thousand dollars. Engines with high compression ratios are not the best candidates for FI without some extra precautionary work (perhaps lowering compression by getting a thicker head gasket, getting bigger injectors, water injection/intercooling to keep charge temps down, etc). The problem is that FI increases the effective compression ratio, which can cause serious damage if you're not careful.

Another thing to keep in mind is that heat soak is a big issue with SC setups (maybe also for turbos, but I don't know as much about them). Supercharged engines are very sensitive to air temperature and density, more so when they are not intercooled.

I believe this information is correct; I'm not an expert on FI, but I picked up some interesting things while I owned my Grand Prix GTP.

[hfh330i]

:cool: thanks guys, and now I know.

[lip277]

I could add the Diesel engine into the equation and really screw up preconceptions based on the gas fed units.....

Oh yeah, I forgot....
This isn't the Mercedes forum..... he he
(I've been a fan of the oil burners since I could drive.....)

[blee]

I could add the Diesel engine into the equation and really screw up preconceptions based on the gas fed units.....

Oh yeah, I forgot....
This isn't the Mercedes forum..... he he
(I've been a fan of the oil burners since I could drive.....)

So the rules change with diesels? I know that just about every diesel available in passenger cars and semis are turbocharged, but I just assumed it was to make the hp/tq numbers and curves more palatable.

[FC]

I could add the Diesel engine into the equation and really screw up preconceptions based on the gas fed units.....

Oh yeah, I forgot....
This isn't the Mercedes forum..... he he
(I've been a fan of the oil burners since I could drive.....)

I'm already drooling at the possibility of a E320 CDI wagon.

369 lb-ft @ 1800rpm and over 40mpg in the highway. 'Nuff said. :D



OT: Before I got my 190E 2.6 I actually drove a 1985 190D 2.2 NON-TURBO. Check out these specs:

- 72hp@4200
- 96lb-ft@2800
- 0-60 in 18.6 seconds (not a typo)
- top speed 97mph (I could never get my car over 91mph)

You can now understand why my 190E 2.6 felt like it had a V8 when I got it. :roll:

[Doug]

"Injection is nice but I'd rather be blown" :D