loosing boost at 6.5 - 7k rpm upwards
 

have a problem holding boost. im using a .57 trim t3/t4 (.50 compressor/.63 exhuast) which i think should be good enough to flow 10 - 15 psi without goin out of its efficiancy.
i had a mbc set at 8 psi and it held until 6500 - 7000 where its starts to slowly come down .
i got rid of the mbc to see if it was that , using 3.6 psi spring it still kinda drops but not as much maybe to 2 psi. can hold high boost until high rpm so i dont think its a boost leak ,. any one got any ideas or experianced this ?. im stumped

Re: loosing boost at 6.5 - 7k rpm upwards (flangemastermike)
 

Well we definently need to know what motor this is to get an idea of "PSI".

But for reference I have a Turbonetics T3/T04 50 Trim on my SRT and running 17 PSI and I'm barely into the "sweet spot" of this turbo. Turbo should be good for 400-450HP. Now if you have a good K-Series, then ya 15 PSI might be moving alot of CFM, but if its a D-Series then it shouldn't be as big a problem.

Re: loosing boost at 6.5 - 7k rpm upwards (Westrock2000)
 

exhaust setup too please.

setup is as follows

b16a2 with b18c4 pistons (had a little accident tuning) 9:1 cr
pfabrications log manifold
xs power 38mm wastegate
greddy S BOV
T3/t4 .57 (.50 compressor/.63exhuast)
home made 3" downpipe and full 3" exhuast

Re: (flangemastermike)
 

where is the wastegate soarce line hooked up to? i had that problem on my setup when i had the line going to the compressor housing. i changed it to the intake manifold and it held solid all the way to redline.

Change the spring to a tial spring.

i'd bet its the Chinese wastegate....




Modified by Schister66 at 3:45 PM 2/6/2007

Re: loosing boost at 6.5 - 7k rpm upwards (flangemastermike)
 

what type/size/brand air filter do you run??

Re: loosing boost at 6.5 - 7k rpm upwards (vtec.dc2)
 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Schister66 &raquo;</TD></TR><TR><TD CLASS="quote">i'd bet its the Chinese wastegate....


Modified by Schister66 at 3:45 PM 2/6/2007</TD></TR></TABLE><TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by turb20_vtec &raquo;</TD></TR><TR><TD CLASS="quote">Change the spring to a tial spring.</TD></TR></TABLE>

https://honda-tech.com/forums/images/smilies/emthup.gif https://honda-tech.com/forums/images/smilies/emthup.gif https://honda-tech.com/forums/images/smilies/emthup.gif

wastegate vaccum is off the inlet manifold. but the BOV is also T'd off the line. air filter is a fine metal mesh with foam over the top as its kinda tight for space , works well. think u might be right about the "made in a cave" wastegate. think a tial is gettin purchased soon.

I have used an ebay tial style wastegate with a tial spring with no problem. That was in my old setup when I had it on my hatchback.