2nd turbo not coming in, but only when "drag start"

[Lude]

if i am driving the car steady, then slowly nurse the accelarator in,

 

the car will boost all the way from the 1st turbo and the 2nd turbo will come in lovely, and boost to 1.4 bar

 

if however i am in 3rd gear for example, and am in the 2nd turbo (above 1 bar boost) then come off the accelarator, the boost will drop obviously,

 

but then when i floor it again in the same gear i will only hit 0.7bar (the 1st turbo max, and the 2nd wont come in)

 

but if i nursed the acelarator in it will come in nicely.

 

 

same if i do a drag start, i will only hit 1st turbo max boost and 2nd wont come in. but if i nurst it in the turbo would come in

 

 

 

ive removed the pipes on the IACV VSV after the car has been standing for a bit, and it does make a woosh noise, so asume this is working?

(there are 2 pipes onit, only 1 wooshes tho when remvoed not the other?)

 

 

whats wrong? is it the pressure tank or something?

Edited July 18, 2010 by Lude (see edit history)

[Andy Blyth]

ive removed the pipes on the IACV VSV after the car has been standing for a bit, and it does make a woosh noise, so asume this is working?

(there are 2 pipes onit, only 1 wooshes tho when remvoed not the other?)

 

 

whats wrong? is it the pressure tank or something?

 

How long is "a bit?" If it's a couple of hours or more then I'd say your pressure tank is fine. You can also rule out leaking IACV or EGCV VSVs.

 

When you quick apply the accelerator, have you tried waiting till the redline (don't do this too often!) to see if the 2nd turbo comes on eventually? I would suggest doing a test of the EBV VSV (labelled "4" below) next.

 

 

Start by removing the hoses and trying to blow down one of the ports with the engine off. The port should be blocked. Next remove the electrical connector. With some bits of wire, connect one terminal to 12V and the other to ground (chassis). Repeat the blow test, air should pass from one port to the other. If this is the case then the EBV VSV is OK.

 

Failing that, it's time to start troubleshooting the ICAV and EGCV VSVs to see if they're intermittently jamming closed.

[AlexJames]

I had this problem, was just split hoses for the ICAV, EGCV as mention above...

[kill1308]

I had this problem too, put the car into TTC mode to do a test and it boosted normally in 1st gear. When in sequential mode the 2nd turbo does not come online as it should and you don't get the boost you'd expect.

 

Reckon it's the same problem?

[Lude]

How long is "a bit?" If it's a couple of hours or more then I'd say your pressure tank is fine. You can also rule out leaking IACV or EGCV VSVs.

 

45 mins ive tested the other day. and when you remove a pipe it wooshes.

 

When you quick apply the accelerator, have you tried waiting till the redline (don't do this too often!) to see if the 2nd turbo comes on eventually?

 

yea mate youl just be on 0.7bar (1st turbo max) and thewill just limit, the second tub wont come in.

 

 

il test the EBV VSV then, and check as many pipes as can (had a quick look seemd ok)

 

 

just seems odd how the second turbo will boost if i nurse the acelerator in, and when its in its really noticable (over 1.2bar boost)

Edited July 19, 2010 by Lude (see edit history)

[Lude]

right finally got round to checking the EBV VSV.

 

 

i wasnt sure which pipes you wanted me to blow down, but i checked my setup and it differs to the diagram above.

 

 

heres mine.....

 

 

this correct?

 

i have noticed a half split in the wastegate pipe, but its been taped over. needs replacing, but what about my setup in my pic?

 

surely the pipe from the VSV needs to be connected into the one should be (thats had the boost solenoid conected to)

 

?

[nevins]

Worse case scenario is your turbos impellers are shot, ask jason all about it lol

[Lude]

update:

 

the split wastegate pipe, ive completly seperated it in half, and put a T piece init (to join them together)

 

then blocked off the spare take off.

 

 

seems to have improved when im doing drag starts, but still not when i come off the gas and slam back on.

 

need a new pipe to eliminate that,

 

but still tho there is no air leaking from the T piece? any views on above ?

[Andy Blyth]

The pipes you have shown in your picture above control the pre-spool of the second turbo. This may explain why you have to "nurse" the accelerator to get boost from the 2nd turbo.

 

I'd put the pipework around this VSV back to stock before going any further.

[Lude]

The pipes you have shown in your picture above control the pre-spool of the second turbo. This may explain why you have to "nurse" the accelerator to get boost from the 2nd turbo.

 

I'd put the pipework around this VSV back to stock before going any further.

 

cheers mate,

 

 

what about the boost controller which is plugged into the pipe, shall i just T into it?

[Andy Blyth]

what about the boost controller which is plugged into the pipe, shall i just T into it?

 

Personally, I'd remove all the hoses to the boost controller for now. Get it working in the stock setup then add the boost controller later.

 

The boost controller shouldn't go anywhere near the bypass valve VSV. It needs to be plumbed into the pressure feed from the first (front) turbo and the wastegate which is right next to it.

[JODY T]

I agree with andy, put it back to stock, make sure all the pipes are free from bungs and try it stock, then fit the boost controller to the first turbo, one pipe goes onto the top of the actuator (it has two feeds) and the other into the turbo housing above the actuator..

 

you then block off the larger pipe that goes into the vsv at the front of the block, and do the same to the one that comes off the vsv to the bottom of the actuator..

 

This should work just fine

[Lude]

all sorted now

 

connected all the stock VSVs as stock,

 

removed the boost controller from the incorrect place and fitted it properly.

 

 

now i get second turbo online in drag starts, and when i lift off the gas & slam back on

 

thanks