FOrSfEd

I see some people do this. Does it affect anything or help anything. I think I've tried it before but I could not boost past 2LBS.

DaX

iTrader: (1)

Here is my thought on why TiAL recommends using a pre-throttle-plate boost source for the wastegate:

Obviously if you use a post throttle plate boost source, the wastegate will see boost and vacuum. Why would this be bad for the gate? I couldn't come up with an answer for a while.

Let's say you're using a proper MBC [like TurboXS] that bleeds off pressure and you're using a correct pre-throttle plate boost source for your wastegate. When in boost, the MBC does it's job...it bleeds pressure off to the atmosphere. When in vacuum [throttle plate closed], the gate see's no vacuum...no harm done.

Now let's say you're using a proper MBC and an incorrect location for your wastegate boost source of post-throttle plate. When in boost, the MBC again does it's job of bleeding boost off to the atmosphere. But now when you're in vacuum, both the gate and MBC are seeing vacuum. The MBC is an open system vented to the atmoshpere, and now when in vacuum, it's sucking air back through the MBC to your plenum - a vacuum leak.

I don't know if this is really how it goes down...I haven't had time to test it out, I was just thinking about it the other day on the way home. If I'm completely off my rocker, someone please throw a tomato.

FOrSfEd

Thats some damn good insight. ANyone else thanks

Boofster

There is also the issue with delay. You will not see the same boost after the throttle plate that you see at the compressor at the same time. If you hook up the WG post throttle plate (aka intake manifold) it may be too late in responding and you may get boost creep.

FOrSfEd

up

Griffin@Camtech

interesting thoughts. I had mine installed that way and the car wouldn't boost past 4psi tho. any instight into why?

RyanEJ8

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Boofster &raquo;</TD></TR><TR><TD CLASS="quote">There is also the issue with delay. You will not see the same boost after the throttle plate that you see at the compressor at the same time. If you hook up the WG post throttle plate (aka intake manifold) it may be too late in responding and you may get boost creep.</TD></TR></TABLE>

....but if you hook up the wastegate to the compressor you will not have an accurate reading either. Some of the boost is lost through the intercooler and piping.

Boofster

I had it hooked up to the manifold, got boost creep past 8k rpm and it never stopped. Changed setup to compressor and the spring can hold it perfectly now. Maybe the theory is wrong but in practice, it works.

gdrum

I had mine hooked from the tial to the intake manifold...and it wouldnt hold what it should it was a 6psi spring and it would just go right by it never ending. So I taped right where the turbo was and hooked it up there and it holds solidly now.

FwdCivicHatch

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RyanCivic2000 &raquo;</TD></TR><TR><TD CLASS="quote">

....but if you hook up the wastegate to the compressor you will not have an accurate reading either. Some of the boost is lost through the intercooler and piping.</TD></TR></TABLE>

In that case you can up the boost to compensate for the loss in your readings.

Boofster

Boost creep on a 0.5 bar spring (~8psi) using manifold vacuum (2.5" flared to 3" dp to 3" catback with POS drag manifold). The yellow is a run with the compressor hole open cuz we forgot to cap it



Best way is to dyno it and set it to whatever setting works best for your boost level and makes the smoothest curve. We found that setting the controller to even what the spring is makes a better curve than just the spring alone.

Second dyno after switching to compressor. Spring by itself holds at 8psi but I raised the boost to 10psi and tuned for that. There isn't that much of a difference but at least it holds. We'll see how the new Inline-Pro manifold does.






Modified by Boofster at 7:11 AM 5/18/2004

nsxmatt

Many people including myself have notice no creep and spikes when using turbine to WG vac lines.

91civicDXdude

I am running a home made turbo setup on my y7/z6 mini. Its a 14B turbo, which you should all know has no outlet nipple on the compressour housing.

I am running my wastegate off of a T'd vacuum line from the intake manifold (post throttle body). I am using a powerup VENOM MBC. If i adjust it, its true that i now have a vacuum leak.

how did i solve this problem? easy. I put a check valve in line with the manual boost controller so that it will only see boost and not vacuum.

Boofster

Added second dyno chart above.