I have a Tial 38mm with the 5 bar spring (7.25 psi), a manual boost controller and have an 3" E-Cutout. Since having an open downpipe causes the boost to raise 2-4psi, what can I do to MAKE SURE that my boost doesnt climb over the 7.25 psi that the spring is for? Can I set the MBC to match the WG spring? Any insight on this would be great, thanks guys.

 

Anybody know what to do here?

 

yeah turn your boost controler down lower to match the MG spring

 

What manifold do you have?

 

Don't use the MBC, shouldn't the Wastegate work no matter what downpipe you have. Open downpipe will make you spool faster but as long as the wastegate is hooked up right it will start venting exhaust when you hit 7.25 psi.

 

I don't know why, but boost does raise 2 psi or so with the cutout open. Its really weird but it does. At least it isn't creeping to 22 psi like me.

 

Yeah I have that problem too when I have my cutout open.

 

yea i had the same exact problem with open downpipe...it was spiking up easily a good 4-5 psi or more. This was on a shitty internal wastegate though.

 

when your running your open DP, adjust your MBC to account for the boost creep.

 

I don't think he is using an MBC to control the boost, what he is saying is he is trying to just run what the wastegate spring is set at.

 

he said he has the MBC, and was wondering if he should set it to the same rate as the WG. to account for boost creep with the open DP, he could adjust the MBC a little lower to even it out

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by FwdCivicHatch &raquo;</TD></TR><TR><TD CLASS="quote">he said he has the MBC, and was wondering if he should set it to the same rate as the WG. to account for boost creep with the open DP, he could adjust the MBC a little lower to even it out</TD></TR></TABLE>

Thats exact what I want to do. The reason is that this is on an H22A4 and I don't feel comfortable running over 7psi , so even with the open downpipe, if I matched the MBC to the wastegate spring wouldn't tha make it to where the boost wouldn't go over that psi? You guys are giving good info so post more replys.

 

you can't lower boost with a mbc so i don't see how that would work.

 

 

I have an idea. since you can't lower the boost below the WG spring setting (7.25psi) and If I was to have my MBC down to the lowest setting, wouldn't that make it to where the boost wouldn't spike then?

 

Why not change the wastegate spring to a lower rate spring to take into account the creep? you want to run 7psi but have a 2 psi creep, put a 5 psi spring in the wastegate, with the 2 psi creep, your back to 7 psi.

 

I will do that if i need to, but i was just seeing if there was a fail safe way for me to prevent it from creeping with the parts that I have right now without having to order a new spring.

 

There kinda is as I'm sure you thought of. Cork up the exhaust, but then that would defeat the purpose of the cut-out.

I use to have the same problem. Ended up playing with the wastegate springs and a boost controller to get the street and stip boost levels just right.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BB6-213 &raquo;</TD></TR><TR><TD CLASS="quote">I have an idea. since you can't lower the boost below the WG spring setting (7.25psi) and If I was to have my MBC down to the lowest setting, wouldn't that make it to where the boost wouldn't spike then?</TD></TR></TABLE>

Does anybody know if this would or wouldn't work?

 

Bump for the day