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Flip
28-12-07, 00:06
At the moment I am running BPU in my J-spec with an AEM boost controller on the second turbo, making me around the 1.2bar mark, giv e or take. However on the first turbo I guess it makes around 0.8bar, all fairly normal. I find the transition from one to two is quite a jump, and this is great fun some of the time, but a little smoother would be nice (like it is with the boost controller off, bringing the second turbo level down to nearer 1bar in the summer).

I am wondering if I might be able to pop a manual boost controller on the first turbo, and raise it to 1bar, thus making the transition from 1 to 2 a bit smoother, and giving me more power into the bargin. I've found posts where people have done this, but with no replies from the experts. Before I go playing, I wanted to know what people think on this, and also what is a sensible/safe level for the first turbo.
tucky40
28-12-07, 11:34
Very interested to hear the opinions on this.
Thorin
28-12-07, 13:39
It is possible, I think there used to be an article on mkiv.com but I'm too lazy to go search for you. I think Ian C may have done this once upon a time (back when he was still on hybrids) but I may be mistaken.
Thorin
28-12-07, 13:52
This might have been what I was thinking of on mkiv.com

http://mkiv.com/techarticles/ebv/ebv.htm
Flip
28-12-07, 13:57
Ah ok thank you, I was looking as well... That EBV article doesn't sound too good for the second turbo though...

I thought you might simply be able to put in a boost controller or a manual bleeder in the first turbo's wastegate setup, much like you do for the second one, then you can just "wind it up" a bit to match the increase in the second one, and hey presto, smoother transition?
Thorin
28-12-07, 15:13
I thought you might simply be able to put in a boost controller or a manual bleeder in the first turbo's wastegate setup, much like you do for the second one, then you can just "wind it up" a bit to match the increase in the second one, and hey presto, smoother transition?

You can, and I know people have set say first turbo to 1.0bar then 1.2bar when the second comes on-line. How it's all plumbed together I have no idea!

Drop Ian C a PM perhaps?
Wez
28-12-07, 15:28
Prob not much use to you but I did this when running the stock turbos with the AEM, all software controlled.

Was also able to smooth the transition out as you can control when each VSV is activated.