Thread: Tcv

**Craigtange** · Tuesday 1st September 2015, 17:50

Ok this might not make sense. my v70r is running 24psi boost At the turbo but the car isn't boosting as it should, according to IPD the stock TCV can only handle 16-18 psi, is this true. I have no fault codes at all and car idles fine. Even the guy at the diagnostic place is puzzled by this. Any ideas folks sorry that this topic is continuing for so long, I have thrown money and time at this with no joy in a soulotion.

**twr** · Tuesday 1st September 2015, 17:57

So lets get this right 24psi??? On stock rods? And how do you no its running 24psi have you an aftermarket gauge? If so possibly the gauge is faulty..... as 24psi is very high

**Craigtange** · Tuesday 1st September 2015, 18:08

It's running a stage 2 Rica re-map. This was done whilst running the car through a laptop and a gauge to check also. Whilst driving the car not rolling road. Sorry it's a 2005 v70 r

**twr** · Tuesday 1st September 2015, 18:12

Sorry now i understand.... i was lead to beleive the stock tcv can handle more than 16psi but i could be wrong. I am.sure.somebody will be along soon to help you mate

**ExternalError** · Tuesday 1st September 2015, 21:08

still 24psi is alot, 1.5 bar is roughly 22psi which with a good map should give you 340ish bhp, if your saying your running 24psi what injectors do you have?
Also 1.5 (22psi) bar is near the safe limit of the k24 on a standard setup do you happen to have a maf reading at 24psi as this will show the actual air moved by the turbo rather than the pressure build up.
I make around 360ish bhp at 1.2 bar with a maf reading of 1074kg/h as my engine breathes alot better with the ported head and exhaust and inter-cooler upgrades but im at the upper limit of a k24 interms of airflow.

**Craigtange** · Tuesday 1st September 2015, 21:27

I am not 100% sure I will find out more tomorrow, I am just going on the info I got over the phone from the diagnostic guy. I just don't understand why everything seems to be working but no boost. Every pipe and everything has been double checked I haven't change the TCV but the symptoms don't seem to suggest it's that. Can hear the turbo spooling up fine. Might get home to put on the stage 1 map and see what that does just out of curiosity.

**ExternalError** · Tuesday 1st September 2015, 21:39

When you say no boost do you mean not at all because that would suggest the waste gate is either locked open or you have an air leak somewhere. if thats the case i cant see how you are getting a 22psi reading as with either of those 2 issues the pressure wouldnt build up. The car may be stuck in limp mode due to an uncleared code or unresolved issue to find out have the codes read as this would have a similar effect. Other than that maybe the TCV but in my experience its normally means it cant hold boost rather than give no boost at all.

**Craigtange** · Tuesday 1st September 2015, 22:04

Sorry, it does boost a little, there are no codes showing at all, he seems to think the the TCV is working/ not sure how you test this. I will put up better info tomorrow after I speak to him. I was driving when he called. Sorry for the broken info, my brain is getting pretty fried with this issue over the last 4months.

**Craigtange** · Thursday 3rd September 2015, 08:28

car is fixed and running well, very well. That's all I can say, far to embarrassed to mention anything else. thanks to everyone on the forum for all the help and knowledge they have shared. I wont take 100% of the blame though as many mechanics have looked at this car including Volvo and 2 x diagnostic guys.

**M-R-P** · Thursday 3rd September 2015, 08:46

Sounds like someone's plumbed the tcv in backwards

**Craigtange** · Thursday 3rd September 2015, 09:28

correct, bloody ridiculous isn't it. more disappointed in myself because my mechanical knowledge should have spotted that, but after being told by several qualified personnel that it is ok i completely overlooked it. car is now holding a steady 22psi of boost. feels like a new car

**ExternalError** · Thursday 3rd September 2015, 10:26

oops ha and 22psi sounds a bit more healthy for the k24. it would be good to get a maf reading just to see how much air is actually flowing at 22psi.

**Craigtange** · Thursday 3rd September 2015, 12:15

Originally Posted by ExternalError

oops ha and 22psi sounds a bit more healthy for the k24. it would be good to get a maf reading just to see how much air is actually flowing at 22psi.

i have one of those elevate air management systems and the vent on the bonnet follow by a uprated turbo intake pipe. i just fitted one of those do88 over engine pipes also with all the intercooler pipes also (still running standard intercooler) nice addition and looks loads better than the standard one, which had a small crack on the mounting bolts, also foind 3 small holes in the silicon pipe to the turbo. really happy again and the car feels super quick and smooth. need to get her on a rolling road now and see roughly what it is putting out.

**Dream3r** · Sunday 20th September 2015, 14:45

Originally Posted by ExternalError

oops ha and 22psi sounds a bit more healthy for the k24. it would be good to get a maf reading just to see how much air is actually flowing at 22psi.

The maf reading will not be correct due to the new airbox, how much by I don't know you'd need to bench test both.

It's definitely going to flow more air at lower RPM's so might hit maf too high diag, which can be fixed by the tuner.

IMO, 1.2 bar on the T5 is nice, R having a bit more midrange (WD) is nice. Anyhow, you'll taper to 1-1.1 bar anyway @ the redline.

**Dream3r** · Sunday 20th September 2015, 14:47

Originally Posted by Craigtange

i have one of those elevate air management systems and the vent on the bonnet follow by a uprated turbo intake pipe. i just fitted one of those do88 over engine pipes also with all the intercooler pipes also (still running standard intercooler) nice addition and looks loads better than the standard one, which had a small crack on the mounting bolts, also foind 3 small holes in the silicon pipe to the turbo. really happy again and the car feels super quick and smooth. need to get her on a rolling road now and see roughly what it is putting out.

If you can get close to 1050 kg/hr you've hit the limit of the turbo and will read 335-360bhp on a dyno

**Ettienne** · Sunday 20th September 2015, 15:49

Originally Posted by Craigtange

i have one of those elevate air management systems and the vent on the bonnet follow by a uprated turbo intake pipe. i just fitted one of those do88 over engine pipes also with all the intercooler pipes also (still running standard intercooler) nice addition and looks loads better than the standard one, which had a small crack on the mounting bolts, also foind 3 small holes in the silicon pipe to the turbo. really happy again and the car feels super quick and smooth. need to get her on a rolling road now and see roughly what it is putting out.

Plastic ic pipe? I'm putting earlier ally one on