|
850 / S70 & V70 '96-'99 / C70 '97-'05 General Forum for the 850 and P80-platform 70-series models |
Information |
|
T5R boost question / help pleaseViews : 6460 Replies : 118Users Viewing This Thread : |
|
Thread Tools | Display Modes |
|
Sep 6th, 2021, 09:49 | #1 |
Member
Last Online: Jan 26th, 2023 13:31
Join Date: Jan 2019
Location: Maidstone, Kent (But Yorkshire born & bred)
|
T5R boost question / help please
What level of boost should be displayed on the stock boost gauge under full boost?
The needle on my car goes about 1/4 into the white section, and there doesn't feel to be the surge of power I would expect. Are there any obvious things I can check? I've looked at the lines from the turbo to the TCV and everything is now connected (the blue line to the fresh air link wasn't connected at the tree ). The hoses do feel a bit crumbly on all three so could there be a boost issue there as a result? It doesn't feel as urgent as I think it should, so any advice would be welcomed. Many thanks Mark This is a recent purchase (two days old!) so I'm still learning the quirks of the car. It has near full history. Recent turbo rebuild, and the PCV has just been done. Looking for guidance please as I learn to hopefully gain trust in it! Last edited by Pupbelly; Sep 6th, 2021 at 10:08. |
Sep 6th, 2021, 14:23 | #2 |
VOC Member
Last Online: Today 17:34
Join Date: Mar 2008
Location: Northampton
|
I cannot help with the boost issue, but just wanted to say glad you have found a car that appealed to you and hope you have many happy miles in it.
__________________
2001 V40 2.0lt Sport lux - Daily Driver. 174k miles. 2003 C70 2.4 GT Convertible - Garage Queen. 65k miles. http://www.neptuno6benagil.com |
Sep 6th, 2021, 15:33 | #3 | |
Member
Last Online: Jan 26th, 2023 13:31
Join Date: Jan 2019
Location: Maidstone, Kent (But Yorkshire born & bred)
|
Quote:
I'm hoping it could be just ageing vacuum lines but if there are any other pointers then hopefully someone on here can help. Whilst the turbo gauge does show negative on the scale then just into the white on the dashboard, it doesn't feel like I think it should i.e. a good linear shove of power, or even an old school wallop of boost at around 3k. Vacuum pipes, intercooler hoses...? Anyone?? Last edited by Pupbelly; Sep 6th, 2021 at 15:35. |
|
Sep 6th, 2021, 17:56 | #4 |
Master Member
Last Online: Mar 11th, 2022 22:01
Join Date: May 2010
Location: manchester
|
Boost issue
You could really do with an accurate boost gauge and also as regards to lack of power it all depends on what you are comparing to. I have said before in previous posts that I find the standard T5 engine lazy especially compared to modern cars.
Once you have an accurate reading of the boost pressure firstly I would get back to basics check or better replace all the vacuum hoses and check all boost hoses intercooler ect for leaks I use a smoke Pro for this. I remember on my me7 v70r it was the wastegate control valve caused an issue where the car would be savagely quick then nearly no boost |
Sep 6th, 2021, 20:10 | #5 | |
Member
Last Online: Jan 26th, 2023 13:31
Join Date: Jan 2019
Location: Maidstone, Kent (But Yorkshire born & bred)
|
Quote:
If that offers nothing then I’ll do the intercooler pipes. I would have thought a T5-R with circa 240bhp would have a good shove when on boost. One thing I noticed tonight, if I rev the car with the airbox lid lifted I can hear the turbo but there’s a momentary whistle briefly, not turbo whistle and actual as though a person were to whistle a short sharp “peep” as you blip the throttle. Is this an indication of a leak somewhere that is being voiced through the airbox lid?? All thoughts welcomed!! |
|
Sep 6th, 2021, 20:12 | #6 |
Member
Last Online: Jan 26th, 2023 13:31
Join Date: Jan 2019
Location: Maidstone, Kent (But Yorkshire born & bred)
|
Where does the turbo control valve take its electrical information from? Could it be faulty?
|
Sep 6th, 2021, 21:15 | #7 | |
Master Member
Last Online: Mar 11th, 2022 22:01
Join Date: May 2010
Location: manchester
|
Quote:
|
|
The Following User Says Thank You to andrewc1267 For This Useful Post: |
Sep 7th, 2021, 10:45 | #8 | |
VOC Member
Last Online: Jan 20th, 2023 10:58
Join Date: Sep 2020
Location: Tittensor
|
Quote:
http://www.vpcuk.org/forums/showthre...o-they-compare The standard settings for the T-5R are 11 p.s.i. on overboost (which supposedly lasts for up to (but not always) 30 secs, and 9.5 p.s.i. under normal conditions. 11 p.s.i. corresponds to fractionally over 2/3 into the white, 9.5 p.s.i. is a bit under 2/3 into the white. My own standard T-5R (automatic), when I kick down, shows initial surge for 3 or 4 seconds with the needle about 5/6 into the white zone (roughly 13 or so p.s.i.) dropping back to the 11 p.s.i. point and then slowly easing back to around the 10 p.s.i. point. These have all been confirmed using an accurate additional gauge temporarily plugged into the vac tree. I've also attached the vac diagram for the T-5R. Assuming all your vac pipes and turbo pipes are sound and clipped up tightly, the most common causes of poor boost seem to be firstly, a damaged diaphragm in the TRV (turbo recirculating valve) followed by a faulty TCV (Turbo Control Valve). Neither of these would be audible. Wastegates are surprisingly reliable, even at huge mileages, but can fail due to weak springs and/or poor seals. If the wastegate is the issue, I would replace with one from Forge. They even tell you how to set it up easily without gauges, spring balances etc. The turbo itself is unlikely to be a problem as at that level of poor boost, there would be other symptoms from the turbo (oil burn/noise) I'm sure. Worst case scenario would be a split intercooler but you would almost certainly hear the escaping boost. Hope this all helps to some degree. John
__________________
Past : 96 855 T5 CD ruby red, 98 C70GT T5 coupe Saffron, 04 C70GT T5 convertible Navy Present : 95 855 T5R Gul Yellow 08 C30SE Lux T5 Polestar 11 C70 Solstice T5 Polestar 19 XC40 T5 R-Design Polestar |
|
Sep 7th, 2021, 11:32 | #9 |
Member
Last Online: Jan 26th, 2023 13:31
Join Date: Jan 2019
Location: Maidstone, Kent (But Yorkshire born & bred)
|
Thank you JohnM 855 T5R Interesting to get some idea on boost figures there, that points to a certain boost loss as I thought. I've ordered some silicone pipework to do the vacuum hoses. How available are the turbo control values and turbo recirculating valves? Is there a way they can be checked before I purchase new / replacements?
I gave the car a detour to work this morning and it is lacking in 'go' for sure. My daily driver is an Impreza and ok its a totally different car but there is no surge or oomph at all to the point where I feel the turbo is not offering anything of value. Disappointing because it has been a looked after car. It just needs a little something, but I need to establish what that 'something' is without just throwing money at it. Helpful VPC link too - Thank you. Last edited by Pupbelly; Sep 7th, 2021 at 11:46. |
Sep 7th, 2021, 12:16 | #10 | |
VOC Member
Last Online: Jan 20th, 2023 10:58
Join Date: Sep 2020
Location: Tittensor
|
Quote:
The TRV has a diaphragm inside which can split or pinhole. A diaphragm and spring kit is freely available on eBay. Get one made by Kinegawa (they are the original manufacturers) and costs about £30 or so. Easy to fit (one of the bolts is a little fiddly). Just take out the bolts on top of the TRV, pop the new spring and diaphragm in (make sure to use the standard spring which I believe is green). You can get the whole Kinegawa unit for not much more. I replaced mine with a Forge piston type TRV at £150. Supposedly more reliable in the long run but as you see, expensive! You can get this from Forge Motorsports direct or via Parts For Volvos. The original TCV can be ordered through your Volvo dealer via GCP and costs about £130 - ouch! Alternatively, I believe you can fit the Pierburg unit for the early V70 and is available online for about £40 ish. They are not, I believe, specific to each turbo model - the same part works on all 850/early V70 turbos. You can strip the TRV and inspect the diaphragm but once you gone to that bother you might as well stick a new one in. I don't know of any test you can perform on the TCV. I replaced mine because it was cracked and resulted in wild overboosting. Regards John
__________________
Past : 96 855 T5 CD ruby red, 98 C70GT T5 coupe Saffron, 04 C70GT T5 convertible Navy Present : 95 855 T5R Gul Yellow 08 C30SE Lux T5 Polestar 11 C70 Solstice T5 Polestar 19 XC40 T5 R-Design Polestar |
|
The Following User Says Thank You to JohnM 855 T5R For This Useful Post: |
Currently Active Users Viewing This Thread: 1 (0 members and 1 guests) | |
|
|