RESOLVED: My stock TT max boost is 0.6...(now BPU& 0.79BAR)

Afternoon

Having recently got my car back on the road after 7 years and replacing the stock twins with a refurbished (steel internals) unit. I have been slowly buying bits for BPU however after installing the boost gauge (depo racing) I am only seeing 0.6 when it should be 0.76. Every vac pipe has been replaced. I Have compared the drive with Iky's twin turbo which is running a nur spec r cat back only and his kick down seems a lot more noticeable. I understand his will spool slightly quicker with the ceramic internals and the cat back too? My car is not slow but I don't think its as quick as Iky's without doing a side by side run and the boost gauge not reading 0.76 proves it....Does anyone have any ideas? What tests could I run?

I have replaced all turbo related gaskets with Mr T ones, inc exhaust gas control gaskets, the o2 sensor has been replaced too.

has your car been out for a good motorway run and have fresh fuel and spark plugs ? check all intercooler pipes or even the inetercooler it self

that being said a cat back system will help with boost and also bpu vs stock is no where near compairable

You sure Iky isn't running more boost? Taking the cats out makes quite a bit of different especially on kick down.

Also isn't his one a VVTi?

Surely though a steel internaled turbo set won't make a standard boost of .76 as they are not stock units. You'll prob find that as you've replaced the turbos with steel ones they are slower to spool and the exit path is the same as for the jap ceramic ones and therefore flow is reduced to the point whereby the standard bleed off rate will only provide .6 bar. This is just my logic making of the situation, I am by no means pretending to be a know it all.......primarily because I do not lol

You sure Iky isn't running more boost? Taking the cats out makes quite a bit of different especially on kick down.

 

Also isn't his one a VVTi?

No, completely stock non VVTI except for nur spec cat back. NO decats. and TRD mounts.

Surely though a steel internaled turbo set won't make a standard boost of .76 as they are not stock units. You'll prob find that as you've replaced the turbos with steel ones they are slower to spool and the exit path is the same as for the jap ceramic ones and therefore flow is reduced to the point whereby the standard bleed off rate will only provide .6 bar. This is just my logic making of the situation, I am by no means pretending to be a know it all.......primarily because I do not lol

Seems feasable..

has your car been out for a good motorway run and have fresh fuel and spark plugs ? check all intercooler pipes or even the inetercooler it self

that being said a cat back system will help with boost and also bpu vs stock is no where near compairable

Yes I have done 600 miles in the car since the new turbo, I have not changed the spark plugs on it as I was going to do this when I go BPU, car has new oil, new oil filter. I have a fuel filter to put on which is what I will do next.

Surely though a steel internaled turbo set won't make a standard boost of .76 as they are not stock units. You'll prob find that as you've replaced the turbos with steel ones they are slower to spool and the exit path is the same as for the jap ceramic ones and therefore flow is reduced to the point whereby the standard bleed off rate will only provide .6 bar. This is just my logic making of the situation, I am by no means pretending to be a know it all.......primarily because I do not lol

I don't get the technical side of things, what does a UK spec boost at? Mind you I cant really compare as the turbo is slightly different on a UK? Also bigger injectors.

I will ask SlickNick if he had his running on stock and what the boost was showing, he used the same company to get his refurbed, but I believe from memory his car was VVTI and BPU'ed so he may not of noticed... :-/

I have just read Homer's FAQ on BPU

http://www.mkivsupra.net/vbb/showthread.php?94705-BPU-(Basic-Performance-Upgrade)

From the write up its clear that the UK spec works differently from the JSpec, mine is essentially a hybrid so to speak so from what I read/understand I dont think mine will boost to 0.76 (because it doesnt have the larger wastegate like the UK spec) even though both stock UK and Jspec will. Can someone confirm this?

I will probably go BPU with a 1bar restrictor ring, so I should see no more than 1bar and no less, if I see less then there is a leak somewhere?

boost is very surgestive of set up a 1 bar ring still may see you at 0.9 so dont get upset that you dont see it,

Does anyone have any idea what this noise could be? Coming from the pressure tank..after a good thrashing

http://www.youtube.com/watch?v=zFF2V1vOMGY

I would say a leak,

Have you put this into ttc and took it out for a blast to preasurise the system and then watched the egbv acuator arm or pulled a vac pipe off after 10 minutes to see if its still got preasure, this is the best way to check the hole sequential system for a leak,

I have a spare preasure tank in the back on my van if you need it , there is also a vsv over there too

I'll give this a try mate... thanks

Update on this lads....

I skipped a few steps here and went BPU & TTC, the car boosts to 1.2 BAR, however today I wanted to try the normal sequential mode, I am only seeing 0.7/just below 0.8 BAR.

Does this mean the following VSV's could be faulty....

1. Intake Air Control Valve VSV
   http://www.internetwork.org.uk/mechanical/ttc/ttc02.jpg
   
2. EGCV VSV
   http://www.internetwork.org.uk/mechanical/ttc/ttc05.jpg
   

yes the fist picture is the vsv and actuator for the second turbo , ei if your second turbo does not come on line or is very late +5000rpm, this could be why you are sitting at 0.7 as the second turbo is not coming on , can you feel the second turbo?

the second picture is also related to the second turbo also this vsv controls the egbv which lets the second turbo spin up to speed

do your TTC test again and preasurise the system then take the pipe off the vsv going to the acuator in the first picture (short curved vac pipe),this should then release the system preasure . check one that air is released

check two do the same test and leave it some time 10-15minutes and seen if when you pull the pipe off you get a release of air

if not then you have a vacuum leak and should replave ALL vac pipes EVERYWHERE there are lots

if you still get the air release you have a bad vsv and should look at the repair manuals on the first page and check that they have the correct resistance Ohms

me myself i would change all vac pipes anyway could be 20 years old now

yes the fist picture is the vsv and actuator for the second turbo , ei if your second turbo does not come on line or is very late +5000rpm, this could be why you are sitting at 0.7 as the second turbo is not coming on , can you feel the second turbo?

 

the second picture is also related to the second turbo also this vsv controls the egbv which lets the second turbo spin up to speed

 

do your TTC test again and preasurise the system then take the pipe off the vsv going to the acuator in the first picture (short curved vac pipe),this should then release the system preasure . check one that air is released

 

check two do the same test and leave it some time 10-15minutes and seen if when you pull the pipe off you get a release of air

 

if not then you have a vacuum leak and should replave ALL vac pipes EVERYWHERE there are lots

if you still get the air release you have a bad vsv and should look at the repair manuals on the first page and check that they have the correct resistance Ohms

 

me myself i would change all vac pipes anyway could be 20 years old now

Every vac pipe was replaced as part of the restoration. TTC working and boosting to 1.2 bar does this not suggest that the hoses that could be at fault are the ones taken out of the equation when doing the TTC, those have been checked and are good. I am trying to source some VSVs but I will try your pressure test. Cheers Mellon

Sounds like the pressure tank system is at fault.

Put the car into normal sequential mode, take for a quick run and get on the boost. When you come back check the actuator between the turbos (EBV I think, it's been a while) to check that it's closed. Put the car into the temporary TTC mode, take for a run and get it on boost (you should see 1.2bar like you say). Come back and check the same actuator to see if it's opened or closed, in this instance it should be opened. If it's not.... you have a leak in the sequential system.

Easy as that

if your vac pipes have been changed and you find you still have a leak the it could be the preasure tank like scott says ,

firstly find if you have a leak

Something that I left out then, after a good thrashing of the car and when I bring it home to idle and pop the bonnet, I do hear a leak from the carbon cannister. I asked Iky what it was and he said that his sometimes did the same. Its defo a leak type of noise comning from that area. (sorry I didnt think this would cause the problem). I may have a video of it...

Thats most likely your issue then.

The pressure tank holds the pressure for operating the actuator valves. If there isn't enough pressure then the actuators will remain in place. This will cause a lot of headaches. The main issue is that the intake bypass (I think) will remain closed thus not allowing the 2nd tubby to come in.

Be careful though as it's likely you are running on your 1st turbo only, this is fine at 0.6 bar up till 4krpm etc, but after that you are asking an AWFUL lot of that poor little tubby on its own.

sorry yes i said before about that noise , scott its on the front page defo the preasure tank or vac pipe too it have a listen, bit of a pain to get to mind

mellon did you say you had one for sale?

Weird thing is the 2nd turbo does kick in at 4 so I dont think its running on 1 turbo Scott

Something that I left out then, after a good thrashing of the car and when I bring it home to idle and pop the bonnet, I do hear a leak from the pressure tank. I asked Iky what it was and he said that his sometimes did the same. Its defo a leak type of noise comning from that area. (sorry I didnt think this would cause the problem). I may have a video of it...

I thought we were talking about the carbon canister? The big black thing on passenger side.

Nope I was talking about that thing you had your ear up against yesterday :-)

Iky sorry mate I was talking about the carbon canister, I thought this was the "pressure tank". The leak noise is coming from around that area. (see pic)