boost fluctuation with Zex 53900??
 

I have just recently rebuilt my motor and have been using the ZEX 53900 cam. I noticed that during the vtec switch over i loose a little boost. For example, while in second gear WOT, i'll get 10psi no prob all is dandy. When i shift into 3rd it will climb up to 7-9lbs and fluctuate there till i reach higher RPMs... like 6000 RPM and up. At first i thought it was something funky with my HMT boost controler but it never did this before.

its annoying as hell... anyone else experience this?

Re: boost fluctuation with Zex 53900??
 

What engine and what turbo?

Re: boost fluctuation with Zex 53900??
 

I have the same cam in my D16Z6, and I don't have that problem at all.

Re: boost fluctuation with Zex 53900??
 

SOHC ZC w/VX pistons and Z6 head
t3/t4 50trim .48AR

today i went through and checked all of my couplers for leaks...

i think ive narrowed it down to dirty air filter, although its not that bad, or shitty boost controler.

Re: boost fluctuation with Zex 53900??
 

shitty boost controller is my guess

Re: boost fluctuation with Zex 53900??
 

yeah, but my home made boost controler worked flawlessly before though... i pretty sure its the MBC but i just don't see how the ball and spring go bad? :-\

Re: boost fluctuation with Zex 53900??
 

how much power with the cam?is there a big difference?do u need new valves?

Re: boost fluctuation with Zex 53900??
 

so tonight i took the HMT boost controler apart, which consist of a "t" and nipples on each end, spring and ball bearing... i disasemble it, put it back together and guess what? everything works fine. no more boost fluctuation. ------- gremlins i tell ya...

p.s. i noticed about a 200whp difference with the cam!

Re: boost fluctuation with Zex 53900??
 

I got the same cam and it makes a huge difference. I have some boost fluctuations too, but i contribute it to my mbc.

Re: boost fluctuation with Zex 53900??
 

yeah the cam deffinately makes some noticeable gains and really comes alive in the upper RRRRs. i'm just currently running stock valve train and stock rev limit.