Thread: 88mm VE Build

Don't rethink your goals.

^This

knocking on 12.5:1 = Bad tune for the gas used

x 2. Don't rethink.





This x 2.



Exactly. There are guys runing 12.5:1 on 91 octane. 93 is a bit better though.

correct

it was knocking a touch in the midrange on 93octane alone due to the fact that

1. it was mapped with some stupid additive i thuoght i wanted to use all the time, but at times couldn't

2. it was priobably higher than 12.5 after an idiot machinist seemed to take a fair bit off my block which i tried to compensate for with a thick HG

3. yes, the map probably wasnt too perfect

12.5 is fine on 93, although i wouldn't think 91 would be great i think the ignition you could use on 91 would be lower and negate the point of having the extra compression


My main reason for wanting 12 or just under is due to the thin sleeves with 88mm and after my recent bad experience want to make sure i avoid any risk of knock and extra heat on these thin walls.

Aha I see. Ok good to know! I'm still rediculously noobish on compression.

With n1s 12.5 is not an issue with 92oct and a decent tune. Ofcourse if the tune is off you can knock w much lower cr.

if 91 is all the better i can get on a regular basis, i should probably go no higher than, 11.5:1 ??

80% of it has to do with tuning.

what if I said 13.5:1 or higher could be done on pump with the right cam/tune?

You would probrably say b.s...

Yeah 12.5:1 I tuned on 91 octane pump gas here in az. No knock. Probably need to take a bit of timing away in the midrange or richen it up a bit. I had to work with the Calum tune quite a bit to get rid of any knock. I did that by just richening it up and it went away.