How To Fix Compressor Surge?

[discopotato03]

If thats what your using (pics) I can give some reasons for surge . The compressor looks like an old T04B 8/16 blade wheel which is really a low speed design . Some people try to use them in "Hi flows" and they generally surge because the turbine wants to drive them at a speed which pumps too much air at low engine speed hence the pressure waves and reversals at the spool phase . Judging by the wall thickness of the compressor housings inlet snout its probaby the -24 or -25 version of the 409179 series which is 70mm diametre T04B 8/16 blade compressors .

If you must persist with that thing (pic example) the easiest thing to do is to exchange the compressor wheel for one of the 6/12 blade T04B compressors which are 409826 series and are available in 39/48/57/62 and 70 trim . Depending on what 8 blade wheel it has one of the 6 blade compressors may go in with a little reprofiling of the compressor housing or get another and have it profiled to suit . This is just one option but something tested and proven would be better .

Cheers A .

[bazr33]

what you have said makes alot of sense discopotato03

as when i ran the turbo at 12psi it wasnt really doing it, not pushing enough air for it to hesitate.

18psi just makes it goes nuts,

depending on how much changing the compressor wheel is and mucking round, might be better off buying a whole new turbo.

Even though 12psi didnt make it hesitate, i wasnt happy with the power it was making so will be pointless going back to it.

i'll let yas know what happens

[paulr33]

basically pressure past the compressor outlet is going higher than the compressor can supply, so it surges.

a bit like trying to pedal on a bike down a hill, and gravity pulls you do so fast that you cant pedal quick enough, but with like foot brakes, so your feet are pulled along with the road drive

[wolverine]

how about adjusting the exhaust cam gear and tuning.

also try softening the BOV to the lightest setting will ease surge as it will allow a path of low resistance.

[Dale FZ1]

I tend to agree with Adrian's views about the number of blades affecting how effectively the impeller can push air at lower shaft speeds vs something similar with fewer blades. It could be something as simple as that - often it's not easy to get a spot-on spec when trying something new/different. Older designs shouldn't be dismissed outright just because they're older. They just need to be matched to the application.

320hp @ 16psi is nothing to sneeze at BTW - obviously it has the mumbo to support good power but not able to work across the range. Garrett's tutorials in living colour in your garage??

If you want to know the spec of the impellers, I would recommend speaking with Ross or Josh at Turbo Aust. If they did the high flow job, it will be documented.

Do you know what sort of characteristics or power target your mate had when getting the specs finalised?

[bazr33]

well on matty sprys dyno it had a recording of 300rwhp on 15psi i think

so fairly close to mine,

but it wasnt on his car for long as he put a gt3540 turbo on his car.

speaking to turbo australia was going to be last resort after fiddling around with harder springs for bov.

but after looking at recent posts, it could possibly be goin to first or 2nd option.

Only problem though, is the hiflow job was done by the company before they were known as turbo australia, forget what they were called. So having documents of the specs will be hopeless to find.

thanks for the info guys really appreicated, should be pretty much spot on with fixing this crap.

[Dale FZ1]

speaking to turbo australia was going to be last resort after fiddling around with harder springs for bov.

Only problem though, is the hiflow job was done by the company before they were known as turbo australia, forget what they were called. So having documents of the specs will be hopeless to find.

thanks for the info guys really appreicated, should be pretty much spot on with fixing this crap.

Don't understand why it would be a last resort?? Pick up the phone and talk to them. I can't comprehend how you are going to fix it without knowing what you have.

FWIW, Turbo Australia are a new company from scratch. Check their web page here

http://www.turboaustralia.com.au/downloads...aliaOpening.pdf

See how you go - best of luck!

[Pauly33GTS-t]

what does slide have to say about it is what i want to know, he should know about this thing being a seasoned hiflower and all...

[benl1981]

Bazr33 did you get to the bottom of this?

Im surprised it is ok at 12psi but not at 18. You reckon the problem is only around 5psi on the highway. In both case the wastegate should be pretty much shut!

Ive got a similar issue with a gcg

[bazr33]

yeah i dont know what the problem was in the end cause i changed turbo, well still in the process of

i believe the reason of why it was not doing the surging at 12 but at 18psi, is that air was being pushed through the front of the turbo into the sensitive z32 afm

im pretty sure when i ran the turbo at 12psi, is that i still had a standard afm, which probably didnt pick up the air being pushed through as much.

things you could try, is putting a stronger spring in ya bov, putting a 90 degree bend in ya intake pipe so if air is being forced back through to the afm, it wont be as forceful??

or relocating your afm after the TPS, or run a aftermarket computer that doesnt require afm.

if you figure it out

please let us know