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what boost to run in motor???

Posted: Fri Oct 19, 2007 10:17 am
by compressor
hi guys iv got a fresh forged twincam motor iv just finished and tuned to 7 psi is this ok??? what boost do you run it in at i have been told if its not a bit the motor will be slugish is this true also what revs should i get the limiter set to??

pic of motor
microtech computer
bosch 044 fuelpump
has aries pistons
scatt rods
arp head and mail bolts
fully balanced
balance shaft removal kit
hks 3037 turbo
hks 264inlet and exhaust cams
hks camgears
steampipe manifold
turbosmart externall wastgate
evo 510cc injectors

Show Image: Image

Posted: Fri Oct 19, 2007 5:10 pm
by iXNAY
i beleive u should be running like 14psi day in day out on a motor like that u seem to have built it with all good gear so u should have no problems.

others on here will have better info than myself

Posted: Fri Oct 19, 2007 5:56 pm
by redzone
7 psi is fine for the 1st 1000km, dont go making it swallow heaps of boost before the main and big ends bed in properly or u could have dramas later on...

Posted: Fri Oct 19, 2007 6:54 pm
by Starion VR4
7 psi is fine for the 1st 1000km, dont go making it swallow heaps of boost before the main and big ends bed in properly or u could have dramas later on...
I agree with REDZONE, but once run in...... 14PSI everyday, then 20PSI on the weekend! :beer

Posted: Fri Oct 19, 2007 11:44 pm
by Xentro
Well even on stock internals on a well tuned DOHC you can run 20 PSI without any problems

so with all the upgraded parts more booost should be possible.
The only problem could be that your injectors are too small.

Posted: Fri Oct 19, 2007 11:54 pm
by zippo
get your self a dual stage boost controller ..... $120
swithch between 7 and 14 psi .

drop the oil every 1000ks twice , cruise along and give the thing a good flogging every so often (after the first oli change ).

with 510 injectors dont try to run more than 14 psi .


wip out the evo injectors drop in some 720 cc units and off you go to 20 psi , dont bother any more than that , turbo will not make more ...

if you baby the thing too much it will flip out when you thump it .
you have gone to the trouble of fitting good gear in there , thats what its made for , pushing it to the limit ..... :D

go out and have some fun .......

Posted: Sat Oct 20, 2007 12:08 am
by zippo
i would also re work that cooler piping.... you have forked out a decent outlay so far , for the sake of some custom pipe work and some decent clamps , larger plenum aswell

also that waste gate seems a little large ,42 mm would work much much better , remember the secret is to match , not biggest is best ...

well done on the work you have done ....

:beer :beer :beer :beer :beer

Posted: Sat Oct 20, 2007 1:51 am
by Chryzla
7psi or so for first couple of 1000kms, i like to change oil/filter after the first 500/1000 as there will be metal shavings from the honed bores beading in the new rings.

Drive it like normal except don't maintain a certain rev rage for too long (i.e dont go drivin it interstate but on the flip side dont redline it either.

I look at it that if its going to fail driving it normally (within reason of course, dont take it out drifting bouncing if off the limiter in the near future) then it was destined to fail.

Posted: Sat Oct 20, 2007 2:34 am
by Abalistic
And when you do and oil change... cut open the old oil filter and see whats in there. Gives you a good indication of whats going on.

Posted: Sat Oct 20, 2007 10:23 am
by compressor
ok thanks heaps guys looking forward to running it in

ill keep you all posted calder as soon as it run in i cant wait should run some good times :twisted:


what revlimiter should i run???????

Posted: Sat Oct 20, 2007 5:28 pm
by Sigve_B
I`ve got it :) now i 300hp is a high goal, you guys run to little boost rofl No offence but 30 Psi should work great on a engine like that once it`s broken in.
I run 14 Psi in my starion with only the CO adjusted.. Runs good and have been for a while now :)

Posted: Sat Oct 20, 2007 7:59 pm
by redzone
^^^ yeah but he's not gonna run 30psi on a brand new engine is he?? after all thats what this thread is all about?

Posted: Sun Oct 21, 2007 2:06 pm
by Sigve_B
once it`s broken in

Posted: Sun Oct 21, 2007 2:49 pm
by Chryzla
we dont run in snowy conditions either, it gets quite hot here, and 30 psi reliably in australia? not likely unless its middle of winter and its actually cold for once.

besides 30psi = rofl in my book anyway.