TacomanSI

Well guys i got my car back with the pistions from Earl and the car feels great.
i had it retuned and cannot get the damn car to hold 16psi. We are using the greddy spec b BC. It will boost 16psi untill about 6500RPM then falls off to a steady 12psi or 11psi. we tried all the settings on the boost controller and even swaped to a MBC but that did not effect it.

From what i was reading porting the flapper is not going to help keep that boost steady,but to maybe try another spring on the internal gate. My question is & (i have searched but came up with no how too's or nice write ups). I want to try and get another spring between the flapper and something else on the internal wastegate but not sure what springs to buy or were to latch them too.

any idea's?

TIA

wantboost

iTrader: (2)

port out the flapper... even try using atpturbo's v-band turbine adapter so you can run a 3" dp

TacomanSI

i will do a search on how to port the flapper. I never thought of going to a 3 inch adapter cause i do not want to spend another 500 on a 3 inch exhaust. I might as well get a new manifold external waste gate and downpipe

Leutenegger

What turbo is it?

wantboost

iTrader: (2)

you can still use the internal wg.... you can have a 3" dp and have it go to a smaller diameter

tony1

The turbo might be running out of airflow. If you disconnect the vacuum signal from the wastegate all toghether, what happens?

TacomanSI

greddy 18g
internal gate
greddy cast mani
greddy stock elbow
greddy downpipe


I may look into that and have a 3inch downpipe to my 2.5inch testpipe/exhaust.

Tony1 i have not tried anything like that yet so i am not sure. I can try it out over Thanksgiving but really not sure what your getting at. So i disconnect the vacuum signal from the wastegate and run it under boost what am i looking for? insta jump to 20psi or just the 5.5psi the wastegate should be rated at?

Leutenegger

maximum boost W/G won't open

BoostR41

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tony1 &raquo;</TD></TR><TR><TD CLASS="quote">The turbo might be running out of airflow. If you disconnect the vacuum signal from the wastegate all toghether, what happens?</TD></TR></TABLE>

tony it probably is running out of air at that boost as I was having the same problem with mine. what I did was on the profec B spec 1 is turned the response adjustment to sharp. that allows boost to hover right around 16-17psi. the spec 2 sucks. ditch it cause it will never hold boost. get the profec type s and you will never have a problem again.

the reason it won't hold boost is because of the exhaust housing. DSM 18g's are known to push well past 20psi and hold fine

tony1

Be careful when you try it with it disconnected. If you blow it up, i'll laugh at you. lol

BoostR41

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by TacomanSI &raquo;</TD></TR><TR><TD CLASS="quote">greddy 18g
internal gate
greddy cast mani
greddy stock elbow
greddy downpipe


I may look into that and have a 3inch downpipe to my 2.5inch testpipe/exhaust.

Tony1 i have not tried anything like that yet so i am not sure. I can try it out over Thanksgiving but really not sure what your getting at. So i disconnect the vacuum signal from the wastegate and run it under boost what am i looking for? insta jump to 20psi or just the 5.5psi the wastegate should be rated at?
</TD></TR></TABLE>


the boost would go to where the turbo would start to fall off then fall back.

I run a 2.5" DP but stock elbow and gate flapper btw....just set the response as sharp as it will go

TacomanSI

bleh i have seen serval other people on this board running up to 17psi on a greddy turbo. i just may **** can this whole manifold and turbo for something else and stick with the 12psi for the winter.

I just wanted a cheap easy way to try and have the wastegate hold the 16psi without spending another 600 or more on turbo/parts.

tony1

What is the displacement on your motor?

TacomanSI

we did that. We had it set to sharp on the low setting bamn held 11psi steady up to 8k. we then switched to high boost and sharp setting bamn 16psi untill 6500rpm then would fall off to 12psi. We then tried the gain all the way over to the oppisite on high boost. Bamn 16psi untill 6500 then falls off to 11psi. Thats why we are kinda stumped. I Had tried to follow your setup since i saw your sig awhile back. BoostR41.

Tony1 it would not be the 1st time my motor blew up. i just got this one rebuilt.

TacomanSI

here is the break down on my motor.

2000 honda civic si
b16
cp 9:1
arp head studs
stock headgasket
greddy 18g
RC 440's
crome
2.5inch testpipe
2.5inch exhaust
greddy mani
greddy elbow
greddy downpipe

hope i covered everything.

i posted my dyno sheet awhile back i did 216whp/167tq on stock block with busted ringlands. about 2 months ago on 6psi.

tony1

hmm, who knows. Try unhooking the wastegate and see what it does.

TacomanSI

Thanks for your help guys. I will report back after Thanksgiving and let you know if it worked or i am carpulling with my wife after i blew up my 2nd motor

JDMisGOOD

Maybe its a sign... The car doesn't want more than 11-12psi after 6500...

BoostR41

get a 2.5" DP made from the elbow back and see if it helps

99blusi

I had a 3" exhaust when i had my greddy. Had no problem holding 16psi, just could never get any higher. Even with the wastegate disconnected...16psi was the max.

I ported the wastegate flapper and had a 2.5-3" DP. Profec B spec 2... Rock solid boost