s/c and turbo torque

[SLSduke82]

I'm still very interested in the torque vs. hp discussion. I believe I've worked that one out...one thing I've always wondered...why do turbo cars seem to consistently make more torque that s/c'd cars...often more torque than hp? I understand s/c tq and hp tends to be more linear (i.e. my car pushes me in the seats from 2k rpm up to redline), but am simply curious. Does it have to do with the parasitic nature of a supercharger?

[bc3tech]

my understanding is yes. the draw on the engine from the s/c contributes to a loss of overall tq. like anything else, there's always a tradeoff... w/ turbos you have to deal w/ that lag, but you'll get some higher tq numbers. with the (roots) s/c you get insta-power, and insta-tq, but not as much throughout the band... pick your poison

but, i'm subscribing

[OZERMAN]

subscribed since i cant answer your question, even with a guess

[Boosted_Ion]

Originally Posted by bc3tech

my understanding is yes. the draw on the engine from the s/c contributes to a loss of overall tq.

I've always been under this assumption as well.

Subscribed.

[bigd2010]

ill be checking back..i wanna know as well

[Shabodah]

It's all about flowing air. The supercharger is more efficient at slower speeds, and when at lower boost, thus, well below 5250. Whereas, the Turbo is very efficient at 5250. Sure, the parasitic loss of turning the s/c doesn't help, but if you check any dyno, the S/C is making more torque down low than the turbo, but then the turbo outperforms it at higher rpms.

[NoRemorse]

Originally Posted by Shabodah

It's all about flowing air. The supercharger is more efficient at slower speeds, and when at lower boost, thus, well below 5250. Whereas, the Turbo is very efficient at 5250. Sure, the parasitic loss of turning the s/c doesn't help, but if you check any dyno, the S/C is making more torque down low than the turbo, but then the turbo outperforms it at higher rpms.

See, why that dosn't make sense, is because the same peak tq at a higher rpm means MORE HP.

[Project_Redline]

subscribed as well...

[Shabodah]

Originally Posted by NoRemorse

See, why that dosn't make sense, is because the same peak tq at a higher rpm means MORE HP.

It does make sense, it just depends on where exactly your are sizing your turbo. If it makes peak boost at 4000 rpm's, it's gonna make more torque than horsepower, while most drag car turbo's hit max boost around 7000 rpm's, thus making more horsepower than torque- see turbo LS1's. lol.

Edit: Another thing you have to keep in mind is that the basics of the engine that is being FI'd still come into play, mostly with oversquare and undersquare dynamics.

Edit2:

SRT-4 Bore 88mm Stroke 97mm
Mazda 2.3L Bore 87.5mm Stroke 94mm
WRX-STI Bore 89mm Stroke 100mm

Any other engines in question?

[bc3tech]

oh boy... can't we just get WOP in here to give the final word then lock the thread? i see where this is going already....