How much boost can u put into a 1275 n not have too mant problems?
Just wanting to know how much boost i can run the supercharger at before i have to start worring about the engine blowing up

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hope be back on the road soon with a blown 1275.

Ummmmmmm vague question.....

Rule of thumb is 4-5 Psi then start looking at de-compressing the engine....

I'd limit it to about 18Psi, but then again, I'm aiming for 20Psi for the next Dyno day (damn, secrets out...)

You shouldnt aim for boost, Boost is just showing you how much "back-pressure" there is in the intake system (ie the engine has swallowed as much as it can handle). . . aim for FLOW ...

I changed from a stock 1100 Cam to the Re-13, lost 4 Psi, and gained a HEAP of power..... its not all about the boost....

J

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well im rebuilding the engine with flow as my main objective, and it will have lowered compression to suit boost. I was looking at prob running 14psi but im lookin about 120hp @ the wheels.
Im open to suggestions n ideas.

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hope be back on the road soon with a blown 1275.

with the right tune, cam and head on 14PSI to get 120 HP at the wheels easy as.
I run upto 18psi and mine is still together getting a little smokey but its been 5 to 6 years now ith the same bearing and rings etc.

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100% Pure A Series Turbo
Morris - The Original RedBull Racing

thanks man
could u pm me some suggestions/ recommendations of what to do to a 1275 to run 14psi or so. Im not sure if i can get away with hone or if i have to bore it out yet cuase im yet to pull it down n send it off to a shop to get the machining done.

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hope be back on the road soon with a blown 1275.

Mini4350,
You are a local guy. What setup are you using? Have you got the buildup underway. I have modified the block, box etc etc etc to handle the power but it will easily hold 21psi at full noise. At the end of the day a 5 port will only flow so much. A decent head job will see you flow over 130cfm. Upping your boost will show resistance within the intake ports so it is more of a balance between head flow and the pressure you plumb it. Having said that high pressures do alleviate the problems of fuel pooling but then there are other problems such as ring blow through that come into it. Drop me a line some time for a chat.
G.

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1970 Cooper S ex-Bathurst & ATCC
1964 Austin Cooper S ex-Group C race car
1967 Morris Cooper S ex-Group B
1962 Mini Speed sports sedan
1968-71 ex-Peter Manton Shell car