Hi all, just installed a boost gauge (need to connect the wiring for the lights still). In 3rd gear, flooring it at 2k revs, the boost reaches 0.4bar by 3k, and beyond that goes to about 0.5-6bar :-( I've looked in the engine bay, the breather hose connected to the 'Y' breather hose has come off, could this cause a boost leak, and the low boost??

Thanks all

Mk1 Octavia VRS

Ps car is standard, no modifications :-)

Anyone?

Thought 0.6 bar was standard boost?!

Standard is about 0.7bar. Mines holds at about 0.4bar until 3/4k, then reaches 0.5bar..

Standard is about 0.7bar. Mines holds at about 0.4bar until 3/4k, then reaches 0.5bar..

Smoke test it

I'm going to replace the split pipe, and then see if the boost is still the same. If it is, then i'll smoke test it :-) My q is, could that split hose cause the low boost? Thanks for the replies :-)

????

It certainly wont be helping

Sent from my iPhone 4s

Is it a decent boost gauge?

I guess so, i brought it off a member on here :-) I also tried out another boost gauge, and it was the same boost levels

When my breather hoses collapsed in my A3 1.8t I lost boost so I'd imagine it'll be having an effect.

If the connection between Y and S breather pipe is lose or has holes your max boost reading should be around 0.4-0.5bar.

Stock boost without any modification is around 0.7bar.

Edited 15 May, 201313 yr by Gonzaga

Yep, boost is between 0.4-0.5bar. Bought a CM replacement hose today, will fit tomorrow! Hopefully should boost fine, and then next week rtech remap! Thanks for the replies :-)

Well replaced the 'S' hose, along with another hose that connects to the 'S' hose, and the results doesn't seem to be good :-( In 2nd and 3rd gear at 2k, flooring it, it goes to 0.5 bar, then to 0.4, then by 5k goes to 0.6... :-(

It might be worth having a look to see what N75 valve it has. You say no mods, but there is a possibility somebody has replaced the valve with a different version, and some versions connect the opposite way round to the standard one. I helped someone on Seatcupra a while back who had bought another valve and had it connected backwards. Has the effect of making the turbo control its own wastegate rather than the ECU controlling it. Made the car run at around 0.5 BAR throughout the rev range. That was a remapped LCR.

Wel it only had one previous owner, an elder gentleman, and he said that there were no mods to the Octavia vrs. I had a look at the N75 valve, whilst the S pipe was being changed, and it looked fine to me, the right way on etc.. :-( Could it be the MAF? The car runs great, other than the issue above :-(

Could possibly be the MAF. Have you tried unplugging it to see if it runs any better? Either that, or if you know someone with VCDS you can check the airflow readings are OK.

Did you notice what version the valve was? The standard one has a part number ending in F or E iirc.

The valve's part number ends in F. And no, I haven't ran the car with the MAF unplugged, I shall tomorrow. And I don't know anyone with VCDS sadly :-( If anyone in Birmingham with VCDS would help me with the MAF readings, I'd really appreciate it :-)

????

Just checked again tonight, 3rd gear, 2k revs, flooring it, at 3k hits 0.5bar. Going to swap over N75 valve, from my brothers a4 1.8t, which he brought brand new late last year, and see how it is. If its the same, next step would be unplugging MAF, and if it's not that, any suggestions? Thanks all :-)

Why not just unplug the maf before swapping N75 valves over?

Why not try the maf before swapping the N75 over? Its easy to do. Only other thing to do if either of those don't work is you're gonna have to get it on VCDS and have a look at boost figures etc, make sure the ECU is actually requesting boost or whether it's being held back for some reason. It's a long shot, but I guess it's possible the MAP pressure sensor has a fault, and is mis-reading boost.

Okie dokie, i'll unplug the MAF tomorrow first and see how it is, and will update :-)

Have a look at the lower boost hose,it joins to the pancake pipe in the drivers side wheel well.The early versions had a single o ring which was prone to giving boost leaks,later ones were changed slightly in design.