TTC Test

Did it to test the tubbies, the second of which is being pissy.

sounds GREAT! real feeling of power on the throttle... everything a go-go until it hits 5000 rpm and just doesn't seem to go anywhere.

I think the tubbies are both fine, but I've been having real issues on vacuum stuff for ages - only on turbo comes in as per norm, at 3.5k!! and then at 4.5 there's compressor surge or lumpiness and the boost drops from .8 to hmm .6. Meant to be in at 1.5, boosting full by 2.5,at .8, then second in at 3.5/4 and boosting at 1.1 bar till 8k! I can feel the power there, it just goes... nowhere.

This test proves it ain't the vsv for the 2nd turbo, it being out the loop.

Anyone else thinking vacuum pipe pinprick or something silly?

FYI I have an HKS EVC V plumbed in and NO CLUE how it should be done. Tried looking at your pics in the past lads, can't really work it out!

does anyone have a step by step setup guide for one I can use as reference?

Sounds exactly like mine, and I'm 99% certain no. 2 has lunched the ceramics

I've checked all the VSVs and actuator valves, all actuators running smoothly, all vacuum lines replaced, and everything is fine. Only way I'm gonna find out is to take off the 1st cat this weekend

Ah but I have one advantage over you - the turbo is a rebuilt turbotechnics hybrid with steel innards, only 2 years old, and the car has been neither ragged truly nor running for nigh on a year correctly... so I don't think it's that. plus when it died the power faded out form the top turbo till it wasn't here any more... which sounds more vacuum to me.

Ahh, if we only had room for twin T74s on the engine

Possibly not ceramics then!

I'd look at checking / replacing the EGBV and EGCV vacuum lines if you haven't already.

Have you physically checked that the EGCV & IACV valves are open. Sounds like the EGCV is open if you heard the sound difference in the exhaust. But the IACV would cause power loss.

As long as these are open then I reckon you should be getting full power from the tubbies. Unless the BOV is passing or you have a boost leak somewhere or the wastegate VSV is acting up but that's just on No-1 I think.

Wire the actuators open instead of relying on boost pressure to open them. Much better test

-Ian

Yeah i have the relevant actuators wired open, but i had a similar problem with no more than .8 bar which was down to the second turbo having seized! but still suffered with no more than .8 bar even after it was replaced, and despite testing all the VSVs and actuators, the only way i get 1.2 bar is to bypass all VSVs etc and just run both turbos off their respective waste gates, i have come to the conclusion that its either a problem with the signal from the ECU to the VSVs, or it is down to the restrictor ring.

Mike M, not really - not entirely sure how to. I'm not 100% turbo conversant yet

Ian C, how would I wire them open? I take it that would mean they pass the full amount of air and should then in theory work correctly?

with both tubbies going for it, I am maxing at circa .5 bar. irritating when I should be on 1.1-2.

I get better response if I only push the accelerator halfway, so not full boost or pressure goes through. To my untutored mind based on what CW and others have said that would suggest boost leak from a pipe would it not?

Here is a pic of the bypass VSV method, in order to not rely on the VSVs and pressure tank to open the actuators, you need to wire the intake air control valve actuator fully open and the gas control actuator fully open.

http://www.imagestation.com/picture/sraid216/pcffa105461a86a3e15c9c99755482be8/ec9c7999.jpg

Thanks for this - I've already done it as recommended but I don't know how to wire the actuators open, so:

a) how do I do this and

b) what does it prove/what should I look for when I do?

Thanks for this - I've already done it as recommended but I don't know how to wire the actuators open, so:

 

a) how do I do this and

 

Best way is, if you have the bypass already set up, both those actuators should already be open, (if not there is a problem with the pressure tank) which will make it essayer to wire, if they are closed then you will need to push them fully open, and preferably clamp them in that position while you wind flexible wire around a close fixed point and the waste gate leaver that the actuator is attached to, and twist the wire so that when released the leaver stays fully open, i'm sure there are some pics somewhere but can't find them at present.

b) what does it prove/what should I look for when I do?

As mentioned above, if the actuators are not fully open when in TTC mode and after the engine has been run, then there is a problem with the pressure tank, if your boost is still low which mine was and i still have not got to the bottom of it, as i have just eliminated all the VSVs and just connected the two waste gate actuators and now get a steady 1.25bar, so at present i have no inclination to go back!

If you buy a Mityvac hand vac / pressure pump you can T piece the pipes to the 2 actauators together, divorced from the rest of the system of pipework, pressurise them with the pump, visually check they both open OK, test drive and see what happens.

Here's a couple of pics that might help mate.

The IACV lever should look like this:-

But a bit further open than mine shown as it's been sitting for a couple of days.

The EGCV should look like this:-

With these open, both tubbies will start spooling around 3K with a bit of a boost spike at 3.5k then you should hear the boost cut back slightly at 4k and then it's steady till red line really.

Hope this helps mate.

Mike