what's the highest compression i can run on 91 octane???

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jspeccrx91

New Member
I got a b20 vtec i'm working on but all i can get around here for gas is 91. gonna keep this one all motor but need to know the highest comp i can go. also my b16 setup now makes peak power at 9200. i plan on using this head so what can the b20 safely rev up too? or what can i do to it to keep it together up there?
 

efhondakid

My name is Byron.
I wouldnt spin it past 6500, the stock redline for the B20s, any higher and youll slowly stretch the rod bolts, and eventually destroy the motor. This is only for a stock bottom end though.
 

jspeccrx91

New Member
dyno proven, fully built head, port/polish, brian cower stage 2 cams
 

Magana559

The Warden
I Would Also Like To See That Dyno Sheet.

Im Going to Run A 12:5:1 CR And BC Stage 3 Cams On Cali 91 pump gas.
 

whiterabbit06

Why oh why didn't I take the blue pill?
VIP
I bet you he had it on the dyno and reved it till it blew and the dyno sheet has a powerband that spans till 9200 rpm at which time he shut it off because he heard a lot of noise. He then decided to make another run and it blew up which is why he now wants to rebuild the motor. If by some miracle chance he is telling the truth and he does have an engine that makes peak power at 9200 rpm then he should know how his engine was built and have some kind of research on how to get it to make power at that range including the amount of compression. This leads me to believe that his claim is either a croc or he has extremely low compression and some really good quality parts.
 

nootrac22

Well-Known Member
VIP
wankel-1.jpg
 

INJEN78

HS LEGEND
ALL ROTO NO MOTOR!!!
bullshit your motor makes pa powr at 9200,thats when my boys fully built b18c5 drops off,and hes making a hell of alot mor power than 182whp
 

jspeccrx91

New Member
my bad i worded that wrong, after looking at my dyno sheet i peak around 8k drop off is 92. sorry for the confusion. no one awnsered my b20 question what can i do to safely rev to 8500-9k
 

NWDRVRBWE

Hands Off my Balls
for a simple answer, reving to 9k is just not a good idea. if you can do it or want to do it, go for it, but let me know how long your engine lasts...
 

Magana559

The Warden
stay at 11:1 cr and only rev to 8k with stock rods and injectors.....it will still go soon lol
 

phyregod

!!YTINASNI
Alot depends on the motor.. Timing, chamber shape, material, surface, etc..

My bike has 12.2:1 compression, runs great on 91. Try that with a 72 ford and it'll knock and ping itself into oblivion.
 
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