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Boost spiking cuntiness


lowlancer

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Helping a mate install a boot controller (bleed type) into his 6A13TT powered Legnum. Apologies for lack of oldschool

All is sweet, all plumbed in correctly afaik.

Here’s a diagram of how I’ve set it up

untitledzq0.jpg

Apologies for quality. That’s all set up right though?

Got boost gauge plumbed into where one actuator was plumbed into, so should be mint.

Problem is, the gauge is flicking up and down hardcore whilst boosting, that’s spiking right? Idles mint, but due to the spiking, it’ll sometimes hit boost cut (13psi approx in these motors) and sometimes it won’t. Was on a cold night too, but I want to eliminate the spiking. Any ideas?

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quite possible that the itsy bitsy teeny weeny turbo's also have itsy bitsy teeny weeny wastegates, that can only flow a given amount of air, and by upping bosst you are not only asking them to open later but also let more gas through (more psi = more air into engine= more fuel in= more exhaust out)

maybe, or perhaps the boost is ecu controlled from the factory and the ecu is working against you...

Maybe

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Especially on twin turbo set ups.

But from what I understand a boost spike is where it usually hits the roof for a sec and then drops back down to normal.. now ehre as bad as boost creep. Yours may be differant if it is continually spiking over and over again through rev range?

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BS fucking twin turbo shit

Serious.

Heaps of TT legacys with taps get it bad.

And a BOV protects turbs from compressor surge so prob not related.

Check the restrictor as this can cause boost spikes. Also,, stupid question.. but if it is installed backwards it will also cause boost spikes. But if the boost has actually risen then it must be in right way.

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Hey

Vr4 twin turbos with wound up boost is not a good mix, the standard turbos are nearly out of there effecntcy range at factory boost levels. My advice would be to tell you mate to sell the boost tap on trade me and spend money on good exhuast and seting up a good cold airbox will probaly find that the gains made will be way better than simply fitting a boost tap

IMO

Justin

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Hmmmm, im not sure thats setup correctly, depending on what brand of boost controller your using?

The boost controller should have an in and an out, and just goes inbetween the wastegate actuator(s) and the inlet manifold. I would get rid of the tee peice closest to the inlet manifold in your setup and just plub the boost controller in there.

Bleeds can be a pain in the ass to setup, as you really need a restrictor in the pressure line before the bleed valve itself. Turbos flow a fuck-ton of air, and quite often if you just try to bleed some of it off, you can't get rid of enough of it to make a noticable difference, thus no difference in boost level. So you add a restrictor before the bleed valve, which means any pressure the bleed valve bleeds off has a large effect. (I NEED TO STOP TYPING BLEED).

Yeah... what kind of boost controller is it? If its a Racepro one throw it the fuck away right now. I've had good runs with the GFB ones that look like a bee-hive. They have a restrictor built into them, and aslong as you set the level you wanted and loctited the screw in place they were all good :).

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