any one boosting on 87 i jsut got one question how much timming do you pull compared to runnong on 91

my set up

b16a all stock compression ect

and im running about 13.75 deg at 11.2 psi column p30 base starts at 24 deg so im running about 1.0 deg a psi retard


how much timming would you typically pull on your boosted set up wehn going from 91 to 87 octane


my dam gasstation keeps on running out of 91 :1

so im thinking of making it run on 87 perminetly!!

hers my bin file
880cc pte
cdm turbo

b16a

 

pull enough to stop it from detonating, then add 2 degrees so your living on the edge

 

cromes timing map is hardly accurate

 

^^ can you explain more indepth here?

 

I run 87 and Water/Meth...I took out 2 degrees from the boost maps.

 

hey xeno,

was it hard to transition from 91 pump to 87 besides just pulling the timing?

also what meth kit are you using?

 

I'm curious on the crome timing too.

 

Water/meth is amazing, we did a buddys talon and went from running 110 to 93 with water/meth, we actuallty had to add timing up to to stop the thing from popping through the exhaust. I don't have dyno numbers, because my slack *** can't afford a awd dyno, but dsm link estimated it at 625 hp.


To the Op, You need to keep a close eye on your plugs, check for denotation. More than llikely peak power willl be past the knock threshold with 87. so you'll think everythings fine but really your at the ragged edge to were a few pings will knock out the ring lands in a split second. If it were me i'd pull keep pulling timing until it starts to missfire, then add a degree or to back in until it runs clean, think the opposite of tuning for mbt. 87 sucks.

 

I run 87 octane on my 12.5:1 CR beater. The ethanol laden "E10" cheap gas is more knock resistant than the good stuff, believe it or not. You take a minor hit in the mpg and power department, but not enough to worry about.

 

So your thinking that because the knock limit on 87 and 93 was real close on your small bore 12.5cr d series, that'll be real close on a 10.5ish b16 with some boost that will have an effective cr of somewhere near 15:1.


From what i'm told, stations are dropping the ethanol content lower since gas is now cheaper than ethanol.