given all things equal: airflow and efficiency of the turbo at the same given PSI. for example: a 50trim will give you MORE HP at the stock boost level of say 19psi as the stock one would at the same given PSI of 19psi. now take the same stock turbo and try to boost it to 25psi and watch the efficiency diminish, where as the 50 trim will start to sing and give you gobs of HP and TQ at the same 25psi. make sense??

this was also discussed before on why a HONDA engine can boost to say 8-10psi and have roughly the same HP level as a 4g63 at stock levels and sometimes more. reason: compression ratio. Honda's have a higher compression ratio 11:1 on most of their blocks, whereas we have 8.8:1. the Honda cylinder head flows MUCH better than a stock 4g63 head.

post #2
https://www.evolutionm.net/forums/sh...onda+head+flow

 

Roughly makes sense. But I want to know why. I want the actual technical explanation of which aspect of efficiency makes this true.

Pardon the thread hijack, I'll go search. Thanks for the info

 

Older generation Audis were equipped with an ECU controlled scramble boost function and would hit near 25 for a few seconds before the duty cycle dropped it down. I dont remember what model in particular but I believe it was the RS4 that C&D did a review on years ago.

In line with the turbo diesel answer, there are Cummins that boost 55psi from the factory (ISX series).

 

the main reason we can run so much boost is the compresion is very low.....

 

the reason is the realtionship between psi and cfm... check out threads like:

https://www.evolutionm.net/forums/sh...d.php?t=140363

 

Thanks, blue

 

Diesel engines accepting turbos lot better than gas engines and it is less complicated process to create TurboDiesel engine. Thats why Diesel engines can run @ higher boosts than gas. PLUS Diesel engine is stonger due to the way it works.

 

The larger turbo pumps denser air into the engine. eg.. it has more oxygen molecules.

 

I completely forgot about turbo diesel engines

 

I think i am going to go test drive one after work just for poops and giggles..