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Help needed please guys

CheltLeonFr

Active Member
Nov 29, 2020
42
22
Cheltenham
So I have an issue which is doing my head in. When I'm on the motorway travelling at a steady 3000 revs in 6th gear I can hear a constant air noise as if the diverter valve is just constantly open, its that sort of air noise. Also when I'm right on the edge of boost (0 on my digital boost gauge) I can physically feel the car jerking ever so slightly. As if it wants to go but hesitates then wants to go again. Then once I put my foot down it boosts to 21/22 psi and it flies as it should. It does go into limp mode on the motorway sometimes aswell and only boosts to 5psi with almost no turbo. I have done all the vac deletes (evap, n249, sai and n112) so the only vac lines left are my inlet to fuel pressure regulator, my inlet to dv and my inlet to brake booster. All the other vac points have been capped off correctly. My Dv is the forge 007p and I serviced it when I put it in a month or so ago with new o rings, new piston and new yellow spring from forge. Im thinking the only thing left that it could be is the N75 or lines going to the intercooler piping or round the back to the turbo. It was doing the same thing before all the vac deletes and the forge dv install.
Also its not throwing any codes etc and when I turn off and on again when it goes into limp mode it resets it and I have full turbo again. Bit strange there are no codes or cel tho. And around town etc there are no problems at all with the running of the car, I do still have that air noise though at low revs. My mate has a leon cupra and his doesnt make the constant shhhhhh noise so it leads me to believe there is definitely an issue that needs sorting.
Any help would be greatly appreciated
 

Sparkie

Angling Adict.
Sep 25, 2009
2,541
779
Middlesex
Smoke test?


Badger5 Custom Map + TIP,
3”Custom exhaust, FMIC, Bosh 550’s, BC Coilovers, ARB’s +loads more.
 

Connor H

Active Member
Dec 19, 2019
1,023
503
Essex
If you still have your PCV system check all hoses and clamps on that too


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Sl1ced

Active Member
Oct 10, 2020
797
404
Sorry no deleted pcv too

Knock yourself a boost tester up with a pvc cap and a bike tyre valve. There is a guide on here somewhere. Listen for leaks/spray with soapy water etc. Plenty of videos online. Perhaps also change the n75 as they’re not expensive anyway


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CheltLeonFr

Active Member
Nov 29, 2020
42
22
Cheltenham
Knock yourself a boost tester up with a pvc cap and a bike tyre valve. There is a guide on here somewhere. Listen for leaks/spray with soapy water etc. Plenty of videos online. Perhaps also change the n75 as they’re not expensive anyway


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Where would be the best place (cheapest) to get a genuine n75? Tried a cheap one on eBay and was only boosting to 14psi when my stage 1 map should be 21/22psi
 

Sl1ced

Active Member
Oct 10, 2020
797
404
Erm I know [mention]Thai-wronghorse [/mention] breaks cars. He’s stopped for Xmas but may still have one knocking about


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Gokiwi64

Geriatric Member
Apr 26, 2014
1,379
722
Hockley, Essex
I have replaced my EMC branded N75 (cheap junk) replaced with a Febi Bilstein from Autodoc paid about £48, annoyingly they lump the C/E/F versions together.
 

CheltLeonFr

Active Member
Nov 29, 2020
42
22
Cheltenham
I have replaced my EMC branded N75 (cheap junk) replaced with a Febi Bilstein from Autodoc paid about £48, annoyingly they lump the C/E/F versions together.
Is the febi one decent and actually work correctly? Don't wanna buy a 48 quid version of the 8 quid one I bought off ebay and only give me 14psi haha
 

Gokiwi64

Geriatric Member
Apr 26, 2014
1,379
722
Hockley, Essex
It seems to work - I have a hybrid turbo (LCR BAM225) - but unmapped and am using a stepper motor type boost gauge and have the alarm set to 16 psi (well as accurate as it allows) and it goes off on a regular basis :) (well when the car is not in the garage drying out).

So very unscientifically yes it does seem to work.
 
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iammooks

Active Member
Nov 27, 2018
1,783
1,172
Blimey postage costs a bomb from that autodoc

Cost me £8.45 to ship a Gates cambelt kit - even though I spent over a ton with them. Then the shipping was delayed and I didn't get it until a few days after I bought one from Jayar instead for about the same price and fitted it.

Moral of the story? Jayar's website is terrible and the best thing to do is just call them and you'll probably get what you need cheaper than Autodoc or BuyCarParts.


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Connor H

Active Member
Dec 19, 2019
1,023
503
Essex
I have the febi one too still in the box, compared to the one I have one It boosted slower and 1-2 psi lower.


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Gokiwi64

Geriatric Member
Apr 26, 2014
1,379
722
Hockley, Essex
Dont forget there are various versions knocking around I think someone did a test or a review of them but I know of "C" "E" and "F" variants - the "F" is what we need for the LCR (again that I know of) - I am not sure if the LC uses the same.
 

CheltLeonFr

Active Member
Nov 29, 2020
42
22
Cheltenham
Dont forget there are various versions knocking around I think someone did a test or a review of them but I know of "C" "E" and "F" variants - the "F" is what we need for the LCR (again that I know of) - I am not sure if the LC uses the same.
Are the n75 valves interchangeable from cupra R to FR version? A guys breaking a cupra R relatively close to me so could I use the n75 from his in my FR
 

Sl1ced

Active Member
Oct 10, 2020
797
404
Yes they are interchangeable. All the same.

I thought they was all different? I saw a YouTube video about them reviewing the differences but I didn’t watch it as I didn’t need too


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LCR AL

Active Member
Jun 5, 2020
82
49
My son borrowed mine (bam) for his auq cupra to test if his was failing (which it was). Felt like a different car, so much more aggressive.

He bought a cheap brand new one and it was as bad as the old knackered one!

In the end he bought a 2nd hand genuine one from a cupra r being broken and it worked perfectly.

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