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Increasing Boost

airbox

By airbox,
in Four Door Family & Wagoneers

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airbox Contributor

airbox

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Been thinking about a boost controller for a while but couldn't make up my mind which way to go, electronic expensive or cheap manual. The cheap manual ones work on a ball and spring and although I have heard good reports on them I didn't like the way they operate by suppressing the pressure to the wastegate rather than bleeding it off as the standard set up. I had tried to just bypass the solenoid but that gave me too much boost and spiky too, so I thought if I bought an adjustable valve and just bled a bit more off than the solenoid does I would get as much boost as I wanted. As standard with the solenoid shut and no air bleeding off then the wastegate opens at 3 to 5 psi, solenoid open and you get 7 psi. This is all confirmed with my boost guage, which although is only a r32gtr one, seems to read right.

So I bought one of these off ebay for £18

6d561.jpg

I had to change one of the male connectors to the bottom and blank off the hole. I then modified the original solenoid bracket and mounted the new valve to it.

imag0192dj.jpg

imag0189x.jpg

I first tried with a full turn out and that gave me about 10 or 11psi, so screwed it in to just over half a turn out and that gave me about 8 and seems to be nice and steady with no spikes or anything.

Very pleased with it, nice and cheap and only took an afternoon pottering to fit.

  • 4 weeks later...
KiwiRS4T Grand Master

KiwiRS4T

Posted
Posted

hmmm does anyone know where I can get one in a hurry? I have a tune tomorrow and forgot to get one of these pinch.gif

You can do this in 10 - 15 minutes for free. Pictures in first few pages of Jaycar thread in DIY section if you need them (post #40)

http://www.skylinesaustralia.com/forums/topic/61207-jaycar-boost-and-fuel-control/page__st__20

This is the 10 minute no cost boost to 0.5 bar rerouting of the vacuum hoses [thanks to SK]. Disconnect the two vacuum hoses from the solenoid. Then connect the boost feed (from the cross over pipe on the left of the picture) to the standard T piece. Connect one side of the T piece directly to the wastegate actuator (on the right of the picture). The remaining connection on the T piece goes back into the inlet via the BOV return pipe (on the standard fitting). Make sure to put the standard brass restrictor in that vacuum hose to bypass the desired amount back into the turbo inlet. The standard bypass hole of 1.25 mm bypasses enough air flow for 0.5 bar. (See photo)

PS: If you want more boost you can drill out the bypass, 1.5 mm = more boost (around 0.7 bar) 1.75mm = a bit more (around 1.0 bar).

pixel8r Mentor

pixel8r

Posted
Posted

wire that wastegate shut. ceramic turbines can run 40psi you know.

not sure the hundreds of people whose turbo has let go at 14psi would agree with you...

Its not the ceramic that is the weak link, so I'm told, its the way it is held onto the shaft. Excess heat causes it to separate from the shaft, at which point it touches the housing and shatters.

You may be right in that other ceramic turbines may be able to handle more boost, but please dont put misleading stuff up on here.

Its been proven many, many times that the RB25 turbo will shatter at 14psi and therefore anything over 11-12psi is not safe for the turbo.

While we're on the topic, I've had a turbotech manual boost controller before and I highly recommend them. I first bought one of the cheaper knock-offs on ebay and it was terrible. So I tried the turbotech and saw a 100% improvement.

Which reminds me, I need to get me another one for my new stagea.

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