stevebez

So been wondering about where the benefits of the larger TB lie ... is it because the engine is simply getting more air - or is it because the S/C has to work less hard to suck air through the TB , so parasitic losses from the S/C would drop off... or is most of the S/C's work done on the compression side, and if its getting more air to compress its maybe working even harder - albeit only slightly!!!!

Why does this matter? Well in the first scenario the car should run a little leaner all else constant, and in the second scenario the A/F would remain constant...

Clearly this mod is a great one (all parts are 100% AMG and almost undetectable)... but more from a scientific standpoint which would be more correct?

dsc

It's because the engine is getting more air. The old rule: more in, more out- big air pump. The car should run leaner also with the same ECU program. Same fuel amount, more air, mean leaner.

ErikGreen

Actually you're car will not be any leaner than it was before this mod. The more air you engine draws in, the more air will pass by the MAF sensor and the engine will compensate by adding more fuel. If a larger TB made it leaner, then a pulley would destroy the engine

jangy

I'm not so sure about that. I haven't really figured out how much the ECU compensates. But, the real point has to do with where our bottleneck lies. It is in getting Air in. The exhaust isn't the hurt side, like the intake is. These cars run pig rich as is and that is why I like the thought of a pulley without ECU tune. Same reasoning goes for the TB.

In all honesty, I believe the effects of TB are nearly as much as the oversized pulley. The gains are similar.

mclarenm8d

I think the answer is both, "because the engine is simply getting more air - or is it because the S/C has to work less hard to suck air through the TB , so parasitic losses from the S/C would drop off".

If I were to keep the camshafts and heads the same but increased engine displacement, I would expect my boost level to go down but IAT to lower and the net would be more power. I believe the TB/airbox and headers would effectively do the same thing, and that may be where some of the benefit comes from.

Jrocket

E55's dont have MAF's.

ErikGreen

Yes, I was informed of this today...Thank you

jangy

Bingo!!

TopGun32

I agree..

I would say the ECU tune is needed for cars that have multiple mods working in combination.

Zod

has any one actuly done a dino with just a TB?

chiromikey

i had exhaust and pulley but i posted pre and post tb dyno and 1/4mile data in vrus' tb thread.

Zod

cheers will check it out

jangy

Look at the '06 SL55 vs the '07 SL55. The only difference is TB. Pulley, etc are all the same. They claim over 30HP.