Boost control solenoid
Originally Posted by daparis
I just installed a mbc & if my calculations are correct I'm running at 24psi. I didn't think this was a problem b/c before the install I was running at about 19-20psi (which I've been told is stock.) If he is running at 14psi, is that really low or is mine way too high?
Also ... 'my calculations' ??? does that mean you don't actually have a boost gauge? I'm not sure exactly how you can calculate boost without measuring it ...
And 24psi is a bit high generally for pump gas on an VIII ... what are your mods (you might want a separate thread to talk about your boost ...)?
I hope the Boost gauge in my EVO II is accurate.
I have the 16G TD05H turbo. I think they call it the small 16G according to what I have read. The big 16G did not come out until the Evo III model.
At this stage I'm going to reinstall the wires on the BCS and monitor the boost to see what differences in performance I get. Worst comes to worst I guess I'll order an MBC so I have some control over what is going on.
WADAD
I have the 16G TD05H turbo. I think they call it the small 16G according to what I have read. The big 16G did not come out until the Evo III model.
At this stage I'm going to reinstall the wires on the BCS and monitor the boost to see what differences in performance I get. Worst comes to worst I guess I'll order an MBC so I have some control over what is going on.
WADAD
Originally Posted by joshd
So is there nothing at all connected to the wastegate nipple? It looks like you're running with the wastegate line disconnected, in which case you will run the max boost possible that the wastegate flapper will hold before just blowing open due to the pressure. This can be unsafe due to the potential for overspinning the turbo, but then again if you're only hitting max 14psi it's probably not all that bad.
I don't know anything about the turbo in the Evo II, so I can't say what the max safe boost is ...
The supra guys used to do this as a super easy mod ... pull the wastegate hose for ~30whp or so
.
The good news is that it seems like you have a very soft spring in the wastegate so you're not overboosting terribly. If I was in your situation, I would hook up an MBC pretty quickly to have control over the boost ... the lines are already cleared for you! Also, how sure are you of the accuracy of your boost gauge? You might want to check it against a 'known-to-be-accurate' MAP sensor ...
I don't know anything about the turbo in the Evo II, so I can't say what the max safe boost is ...
The supra guys used to do this as a super easy mod ... pull the wastegate hose for ~30whp or so
. The good news is that it seems like you have a very soft spring in the wastegate so you're not overboosting terribly. If I was in your situation, I would hook up an MBC pretty quickly to have control over the boost ... the lines are already cleared for you! Also, how sure are you of the accuracy of your boost gauge? You might want to check it against a 'known-to-be-accurate' MAP sensor ...
Yeah I don't know why everyone assumed he would be running "wastegate pressure" (meaning the minimum pressure needed to open the wastegate via the wastegate actuator) since the only way to do that would be to run a hose from the nipple on the turbo cold-side pipe directly to the wastegate actuator. This would obviously be safe, but in all actuality he is running the maximum pressure the turbo could ever produce...which isn't safe or efficient..
OK...
Sorry to revisit this but now that I understand things a bit better I want to be sure if I need a BCS, an MBC or both.
Since I last wrote I have removed the BCS completely. It looks like the plastic was rotten and the hoses just broke off from the nipples on the BCS. I have been unable to source another BCS for my Evo II but people are saying you can just get an MBC and be fine.
MY question is do I still need a working BCS, if I do buy an MBC?
I read in a thread recently that you just cap off the BCS if you are you going to use an MBC but that means the BCS is still wired in to the ECU. I just need to know if I go MBC if I still need the BCS.
Help Please!!!
WADAD
Sorry to revisit this but now that I understand things a bit better I want to be sure if I need a BCS, an MBC or both.
Since I last wrote I have removed the BCS completely. It looks like the plastic was rotten and the hoses just broke off from the nipples on the BCS. I have been unable to source another BCS for my Evo II but people are saying you can just get an MBC and be fine.
MY question is do I still need a working BCS, if I do buy an MBC?
I read in a thread recently that you just cap off the BCS if you are you going to use an MBC but that means the BCS is still wired in to the ECU. I just need to know if I go MBC if I still need the BCS.
Help Please!!!
WADAD
The BCS basically is an EBC .. it's just controlled by the ECU. You can replace it with an MBC/EBC, but you'll probably have to leave the BCS plugged in (electronically) to avoid confusion with the ECU. I've always used the 2 in series though ... letting the MBC reduce the pressure getting to the BCS.
DISCLAIMER: VW guy ... I've never had an Evo II.
DISCLAIMER: VW guy ... I've never had an Evo II.
Put in a MBC and leave the broken BCS pulgged in to the ECU. You could probably remove it totally and get the same results.
If you do this you'll be covering all your bases ... MBC will see boost from the manifold and regulate pressure to the wastegate. The BCS will still be seen to the ECU. If the BCS is mounted in the intake piping, you'll have to cap it somehow.
You can get a MBC cheap, or even make one using a gang valve from the pet store. Try it before ordering OEM parts ... sounds expensive.
If you do this you'll be covering all your bases ... MBC will see boost from the manifold and regulate pressure to the wastegate. The BCS will still be seen to the ECU. If the BCS is mounted in the intake piping, you'll have to cap it somehow.
You can get a MBC cheap, or even make one using a gang valve from the pet store. Try it before ordering OEM parts ... sounds expensive.
Originally Posted by daparis
I just installed a mbc & if my calculations are correct I'm running at 24psi. I didn't think this was a problem b/c before the install I was running at about 19-20psi (which I've been told is stock.) If he is running at 14psi, is that really low or is mine way too high?
He has an evo II not an VIII or IX, so you cannot compair the two.
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