Haveing Problems Making Power When Runnin Big Boost

[timsr33]

MAZMAN i relied to your post on supra forums... small world!! it would drive me insane!

timsr33 i had standard cams.. well bog stock motor 1.4 bar same everthing made 315awkw. lag was almost identical,put the cams in a mild head and went to 376awkw on 1.6 bar.

ive been told its the small cams and weak valve springs... but there are the odd freak ones on here making 400+ kw on same boost. either im missing something or they arnt telling us something..

but you have valve springs. wich make me worry about mine. but yours has crazy lag! what was the "clearance issues" you discoverd?

ps.. my girly has a rb25 and a gt35 with .68 ar rear. she made 345rwkw on 1.5 bar. little 252 poncams and type a springs on a 6 boost. now when i built the motor it made 260kw on 1.2 bar i opened up the small radius on exhaust ports only! went straight to 301kw..

so i think our cyl heads are the place to look at.

my valve clearances were only 0.15 inlet and exhaust and when hey heated up they were opening slightly so i redone the clearances my self and redialed my cams and i can get 1.5 bar in 4 th gear by 4800 rpm but i need to get it tuned again because it is leaning out bad now on boost gettting 14 afr so ill add a bit of fuel and then get mark to put it on the rollers again to see how i goes

Edited March 7, 2009 by timsr33

[timsr33]

I thought i would join in and give you my experience as well.

I however have a supra 2jzgte with a gt42.

Long story short, i have very low power numbers for the size of turbo and boost im running, ive tried a lot of things, people were saying also valve float, small cams etc.. after replacing them, i am still having the same issue's.

My boost comes on hard at 5500rpm@26psi and thats where it makes its max HP, then just flat lines all the way to redline.

All the info is in the links here, i have posted my issue's on a fair few forums, so if you can be bothered, have a read what ive done, im pretty sure we may have a similar issue, also running a haltech e11 and having a hard time finding someone to tune it...

http://www.performanceforums.com/forums/sh....php?t=67205139

http://www.supraforums.com.au/forum/showthread.php?t=37070

http://www.supraforums.com/forum/showthread.php?t=529982

Not sure if you'll be able to go on all of them, may need to sign up? and some are a very long read, but plenty of suggestions, just everything ive tried so far hasnt worked, very frustrating!

i originally had the same problem with the power just flat lining with my old setup then i changed to m and w ignition and it made a massive difference in top end but it was still laggy so thats when i went single and my car went back wards but mine was valve clearance fingers crossed

[timsr33]

problem fixed put car on the dyno yesterday and it made 411.9 kws at 1.55 bar boost and had full boost by 4700

[DRIFTER]

what was it?

[timsr33]

it was a valve clearance issue