Boost Machine Question
03-15-2007, 04:39 PM
#1
AudiWorld Super User
Thread Starter
Join Date: Dec 2004
Posts: 2,155
Likes: 0
Received 0 Likes
on
0 Posts
Boost Machine Question
Since installing my EH'd manifold and phenolic spacer I have been toying with the Boost Machine a little. It seems that no matter what I set the Max boost side at I boost to like 25psi then drop to 17-19 and then steadily climb back up to about 20-22 as the rpms go up. I even set it back to 0 turns and it did this. I have it at 4 turns now and it seems to be just the same as when it was at 0 turns. This is mind boggling to me and I thought that you guys might have an idea.
(my guess is that the valve might be worn out or something like that and it is staying at full open all the time? maybe, but that doesn't make sense.)
(my guess is that the valve might be worn out or something like that and it is staying at full open all the time? maybe, but that doesn't make sense.)
03-15-2007, 04:43 PM
#3
Senior Member
Join Date: Jul 2004
Posts: 7,071
Likes: 0
Received 0 Likes
on
0 Posts
The BM can only increase boost, not lower it
Remove it completely and see what boost numbers you are getting. I suspect that since your boost doesn't change it is never coming into play and something else is increasing your boost. Remove it from the equation and see what happens, it's only 2 hoses.
Trent
Trent
03-15-2007, 04:56 PM
#4
Yup...What Trent said plus...>
Make sure you Zero the onset valve (fully counterclockwise). Has the BM been in regular service Josh? Haven't had a valve faiure yet, but if you let one sit with the Onset on, sometimes the rubber diaphram sticks to the seat and doesn't pass through the air signal. This could cause an overboost and erratic behavior. If this is the case, turn it counterclockwise til it's loose and shoot a little compressed air into the inlet hose. This will unseat the daphram and you should be good. Proceed with normal tuning from there..
Also re-check all the vac lnes under the Manifold that you had to re-connect...
Also re-check all the vac lnes under the Manifold that you had to re-connect...
03-15-2007, 09:22 PM
#6
AudiWorld Super User
Thread Starter
Join Date: Dec 2004
Posts: 2,155
Likes: 0
Received 0 Likes
on
0 Posts
How much PSI to run through the valve with compressor?
I've been playing with it and both of the valves have been to the max and min of both their adjutments, don't know if this would cause a problem or not. I totally unhooked the Boost machine and it spiked much lower it seemed, but still had the max boost in 3rd gear leaning on the throttle of 20psi. I'm really not sure what else to do. (Hoses on manifold are on and good.)
03-16-2007, 03:18 AM
#7
Something else is going on then,,,,
With all the valves in the "Relaxed" position, you can blow into the intake hose. Air should pass through the BM. If it doesn't try the shot of air. 30-40 psi shoud do it if that is the case. Since this started with the manifold install, I would re-trace everything you did. Is the manifold temp sensor harness hooked up? That's an easy one to mis. Stuff like that.