Is timing with 100% meth knock limited?

[mrfred]

I'm tuning a car that is injecting 100% meth. The meth/gasoline ratio is 20-25%. I'm starting to tune for power and wondering if timing is knock limited.

[tephra]

i would think you should be hitting MBT especially at high rpm where the turbo might run out..

[mrfred]

Originally Posted by tephra

i would think you should be hitting MBT especially at high rpm where the turbo might run out..

Any particular reason? Have you got your meth installed?

[tephra]

ive seen people with 50/50 not getting anymore power after a certain timing number... no knock, no more power... so i'm assuming they have hit they MBT...

Particularily for a stock turbo where you run it to 100% @ redline - you just can't get anymore airflow...

nope I havn't got mine installed yet.... soon hopefully gotta get all the parts together

[scheides]

Yes you'll eventually start getting knock. How much depends car-to-car, but being right on the edge of knock is never good, just like when tuning on pump gas. My car runs 5-6°@4000-4500rpm on pump and about 10° on alky.... also 13°@7500 on pump and 21° on alky. Every degree really turns into about 5whp on the dyno.

The above numbers are on my 'kill' tune, 432whp on dyno dynamics. I generally run a more 'street safe' map that I just yanked 2° out of the whole high-load section of the map. That map yields 420whp and is safe as safe can be. I like my car reliable so going for that extra 12whp is just not worth it for me.