Ok first when i floor it and get on the boost, it shoots to 7.5-8psi depending on load and ----.. then it levels out around 7psi then 6.8 or so.. then as i approach redline it goes to around 5.5 5.3 psi!!
why the hell is it dropping like that? what is the cause

ihi rhb5 internal wastegated turbo on a d16y8 with intercooler and 450cc smc 500

 

turbo had no shaft play and was in EXCELLENT condition... spins really good and this turbo is watercooled so that's why it's in good condition... stock WG is around 8psi i have heard... with my intercooler i should be hitting 7psi or so...

 

The only thing I can think of of is that your out of the efficiency range

 

mine does that too... d16y8 w/ t25 set at 9psi.
i think its the waste gate. also it varies in different gears. must be wastegate related.

 

ok have you tried putting the WG signal line right at the manifold or at least after the IC?

i'm going to try someshit like this and see if it'll help

 

yea your out of range for your turbos i test drove a saab the other day and it fell out of boost at like 5200rpm but was fully spooled by 2100rpm it was to under sized for the big 2.0litre in them. so its the same thing your having. just need a bigger turbo!

 

ok if i pull my wastegate vacuum line, the turbo should boost to heaven right?? maybe at least 15-18psi even at redline...

sooooooooo... if i get some boost controller, then it'll up the boost accordingly at higher rpms to accomodate the higher flow right??

 

i don't belive my turbo with the wastegate CLOSED will only give me 5-6 psi at redline on my dinky d16 engine...

my friend holds 7.5psi to redline on same engine...

do you think it's boost leak somewhere?? how can i check this

are dsm 1g bov ----?