Boost problems on 245whp Sohc - Honda Forum / Acura Forum

96scD16 · 10-19-2006, 06:50 PM

I got a question thats been plagueing me and Ive tried almost everything.
Quick setup:
D16y8 built bottom end
SRP pistons, Eagle rods, ARP studs
Stock head
2.5 Dp and exhaust
Hondata
550 injectors
t3/t4 .50/.48 (not sure on the trim)
15 psi, 245whp 202ftq
My goal was 300+!
So obviously, just turn up the boost right? Well, the boost will not go past 15psi!!! I have a turbosmart MBC and a 10.153 Tial wastegate spring. Ive tried everything. No boost leak anywhere, no exhaust leaks anywhere. I have posted this and got some ideas, like take the vacuum lines completly off the wastegate, tried that, still 15psi. I havent put a bigger spring in yet, but some people say that this wont matter. Do you think a bigger spring will raise the boost in my situation or is something else wrong.

2highpsi · 10-20-2006, 07:42 AM

idk if retarding the timing anymore would help?

BurntRubber87 · 10-20-2006, 11:13 AM

Sounds like a wastegate problem..but I dunno..if you tried to unhook the wastegate vacuum line and it only went to 15 PSI I don't know what to tell you..maybe take the WG sprng out and try stretching it out or something..

96scD16 · 10-21-2006, 08:51 AM

I was gonna try the spring next. I'll probably just put in a 14.5 psi spring and see what happens.

Sirfallsalot243 · 10-22-2006, 01:59 AM

Are you maxing out the turbo?

96scD16 · 10-22-2006, 05:42 PM

I dont know. The trubo is a t3/to4e .50ar intake-.48ar exhaust. I dont know the trim. The dyno sheet showed that it was loosing power on the top end. It went from 245@6500 to 210@7500.

g2nickle · 10-23-2006, 04:35 AM

Quote:

Originally Posted by 96scD16

I dont know. The trubo is a t3/to4e .50ar intake-.48ar exhaust. I dont know the trim. The dyno sheet showed that it was loosing power on the top end. It went from 245@6500 to 210@7500.

That turbo should be good to about 400hp. How about shaft play? A sloppy turbo or one that really needs a rebuild could be to blame....

SD6 · 10-23-2006, 03:23 PM

I'm also going to suggest that the wastegate is the culprit. Some sloppiness in the turbo might slow it down a bit, but I've still managed to push 20psi out of a small IHI, with the compressor wheel and turbine rubbing the entire time.

96scD16 · 10-23-2006, 09:16 PM

I think its the wastegate also. The turbo was rebuilt less than 300-400 miles ago, by a company that does nothing but rebuild turbos. No shaft play at all.

2highpsi · 10-25-2006, 07:43 AM

my friend had a turbo ls and for ran into that same problem somewhat. except when his car was cold it would run at 14 pounds but as soon as the car warmed up it would only go to 12 pounds i think and seemed like it was leaking boost. I took the wastegate apart and found out that the diapram (spelling) inside the wastegate was ripped some how. ordered a new wastegate and it fixed his problem held steady at 13 pounds. but he couldnt go past 13 becasue thats how far they retarted the timing. so he says. i never messed with retarding the timing anymore for him so i wouldnt know if that would help you

liquidblue · 10-25-2006, 08:43 AM

just an idea, but check your CAT, see if it is getting clogged. i had this problem on one of my other turbos, the cat was getting clogged and it would just not let the exhaust gas flow fast enuff to spool up the turbo any higher

96scD16 · 10-30-2006, 04:27 PM

I took the cat off. The car has 2.5 DP and 2.5 custom to a resonator back.
I fixed all the boost leaks a while back and still 15. Im gonna put in a 14.5psi spring to see what happens.

I'm Gay on a harley · 11-02-2006, 11:55 PM

what is the exact turbo? and it could be your wastegate itself thats making the problem, and if u wann make some serious hp get your head ported and polished and a nice dyno tune, you should make your numbers from that, good luck

95accordlx · 11-04-2006, 03:04 AM

I doubt ur maxing out the turbo. I can almost gaurantee its a boost leak. I had the same problem on my previous setup. Car would boost real lazy and only go to 12 psi no matter what i do. Found out the BOV connection to the up pipe was leaking at high boost. Next time it happened i was leaking boost from the exhaust manifold gasket.
The hardest part was jus finding the leak.