Samurai 20V Posted January 10, 2015 Share Posted January 10, 2015 (edited) Hi guys.. Got some issues on my BPU TT6. The car has been making a strange noise on the first turbo, sounds like a piece of meat being cut at a butcher, but much quieter. Recently I noticed the car is not making full boost, down by 0.15bar.. Yesterday, took off from a standstill with WOT on first gear, boost was 0, changed to 2nd and then it made boost. Any ideas? Edited January 27, 2015 by Samurai 20V Updated situation (see edit history) Quote Link to comment Share on other sites More sharing options...
TuneR Posted January 12, 2015 Share Posted January 12, 2015 Checked for leaks or that the fins are ok on turbo 1? Quote Link to comment Share on other sites More sharing options...
Samurai 20V Posted January 12, 2015 Author Share Posted January 12, 2015 I seem to have a dud IACV VSV.. Tested it as per the service manual, confirmed it was not operational.. Ordered a new one.. Hope it works out.. Quote Link to comment Share on other sites More sharing options...
Samurai 20V Posted January 27, 2015 Author Share Posted January 27, 2015 Guys, Update on my situation. I have installed a new IACV valve, the issues of no boost or erratic boost is gone.. The new issue is if applying throttle below 4000rpm, the 2nd turbo does not come online. If I apply above 4000rpm, it boosts normally, bringing the 2nd turbo online. I also have another issue in that it is overboosting in the high boost setting, up to 1.37bar. I have an EVC5, my thinking is the boost correction map was setup with the old IACV VSV, with the new one the airflow has changed. I will adjust the map and hopefully cure the overboost issue. Can anyone advise on the first issue? Thanks. - - - Updated - - - Guys, Update on my situation. I have installed a new IACV valve, the issues of no boost or erratic boost is gone.. The new issue is if applying throttle below 4000rpm, the 2nd turbo does not come online. If I apply above 4000rpm, it boosts normally, bringing the 2nd turbo online. I also have another issue in that it is overboosting in the high boost setting, up to 1.37bar. I have an EVC5, my thinking is the boost correction map was setup with the old IACV VSV, with the new one the airflow has changed. I will adjust the map and hopefully cure the overboost issue. Can anyone advise on the first issue? Thanks. Quote Link to comment Share on other sites More sharing options...
Fitz Posted January 27, 2015 Share Posted January 27, 2015 Guys, Update on my situation. I have installed a new IACV valve, the issues of no boost or erratic boost is gone.. The new issue is if applying throttle below 4000rpm, the 2nd turbo does not come online. If I apply above 4000rpm, it boosts normally, bringing the 2nd turbo online. I also have another issue in that it is overboosting in the high boost setting, up to 1.37bar. I have an EVC5, my thinking is the boost correction map was setup with the old IACV VSV, with the new one the airflow has changed. I will adjust the map and hopefully cure the overboost issue. Can anyone advise on the first issue? Thanks. - - - Updated - - - Guys, Update on my situation. I have installed a new IACV valve, the issues of no boost or erratic boost is gone.. The new issue is if applying throttle below 4000rpm, the 2nd turbo does not come online. If I apply above 4000rpm, it boosts normally, bringing the 2nd turbo online. I also have another issue in that it is overboosting in the high boost setting, up to 1.37bar. I have an EVC5, my thinking is the boost correction map was setup with the old IACV VSV, with the new one the airflow has changed. I will adjust the map and hopefully cure the overboost issue. Can anyone advise on the first issue? Thanks. I thought that was how the sequential system works? 1st turbo flying solo until about 4k then the second turbo kicks in? Quote Link to comment Share on other sites More sharing options...
Samurai 20V Posted January 27, 2015 Author Share Posted January 27, 2015 I thought that was how the sequential system works? 1st turbo flying solo until about 4k then the second turbo kicks in? The issue is sometimes after 4k the 2nd turbo doesn't kick in.. Quote Link to comment Share on other sites More sharing options...
Fitz Posted January 27, 2015 Share Posted January 27, 2015 The issue is sometimes after 4k the 2nd turbo doesn't kick in.. Ah, gotcha. Wasn't clear in your post "The new issue is if applying throttle below 4000rpm, the 2nd turbo does not come online. If I apply above 4000rpm, it boosts normally, bringing the 2nd turbo online" Quote Link to comment Share on other sites More sharing options...
Samurai 20V Posted January 27, 2015 Author Share Posted January 27, 2015 - - - Updated - - - Ah, gotcha. Wasn't clear in your post "The new issue is if applying throttle below 4000rpm, the 2nd turbo does not come online. If I apply above 4000rpm, it boosts normally, bringing the 2nd turbo online" Yes, you are right, its not too clear.. To clarify, 2nd turbo only comes only when above 4k rpm and throttle applied, not when throttle applied below 4krpm. Quote Link to comment Share on other sites More sharing options...
Sukhy Posted January 27, 2015 Share Posted January 27, 2015 Check vsv's, boost hoses and feed from the pressure tank. Quote Link to comment Share on other sites More sharing options...
np89 Posted January 27, 2015 Share Posted January 27, 2015 The vsv has an 11psi minimum to open otherwise it won't matter what revs you are at if the first turbo isnt makong the boost, say if you are feeding the throttle on lightly or slowly it wont make enough boost to open the vsv Quote Link to comment Share on other sites More sharing options...
Big Supes Posted January 27, 2015 Share Posted January 27, 2015 Sounds pretty normal to me apart from boost spike. Check for boost leaks for the spiking. Quote Link to comment Share on other sites More sharing options...
Samurai 20V Posted January 27, 2015 Author Share Posted January 27, 2015 Ok, update after driving home.. The car is an absolute madman in terms of performance.. I am seeing 1bar boost in 1st gear, 1.2bar in 2nd, 3rd, 4th, 1.3bar in 5th and 6th. (When both turbos are online of course) I need to adjust the boost correction map on the EVC to curb the overboost in 5th and 6th. The issue is that in any gear if accelerating past the transition phase from lower rpm, the 2nd turbo does not come online. I have to come off the throttle and then floor it again, then I see the full boost as above. Anybody got any ideas? Quote Link to comment Share on other sites More sharing options...
CanisLupus Posted January 27, 2015 Share Posted January 27, 2015 Do the ttc mod with the hoses and see if it is holding pressure after a quick drive. Should be hissing even after a few minutes when you pull off one of the hoses. Quote Link to comment Share on other sites More sharing options...
Guest royNL Posted January 27, 2015 Share Posted January 27, 2015 I had the same problem a few years ago, As I can remember it was a leak in one of these hoses : Quote Link to comment Share on other sites More sharing options...
Samurai 20V Posted January 27, 2015 Author Share Posted January 27, 2015 I had the same problem a few years ago, As I can remember it was a leak in one of these hoses : http://i59.tinypic.com/2le6r76.jpg You are on the money mate! Thanks! I just checked the hoses on the IACV, this is what I found. I guess this was enough of a hole to cause a leak and the boost issues. Apologies for the grubby hands.. - - - Updated - - - Will test the car tomorrow to work and report back.. Quote Link to comment Share on other sites More sharing options...
mellonman Posted January 28, 2015 Share Posted January 28, 2015 http://www.mkiv.co.uk/vbb/showthread.php?35926-The-sequential-system i will put that here just incase Quote Link to comment Share on other sites More sharing options...
Samurai 20V Posted January 28, 2015 Author Share Posted January 28, 2015 Report back after the drive to work... Car is running fine... 2nd turbo is coming online normally.. Just need some tuning on the boost controller to clean up the lower rpm and pull back to high rpm boost. Thanks to all for the help, royNL especially and IanC for his informative threads... - - - Updated - - - http://www.mkiv.co.uk/vbb/showthread.php?35926-The-sequential-system i will put that here just incase Thanks Mate.. This thread was very helpfull.. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.