Minor boost issues...hopefully!

[B3NPM_Cupra]

Hi guys,
bought my cupra last week....fitted my forge split r DV and autogauge boost gauge.....one thing i have noticed is that it boosts to 8/9 psi which is around standard..but everyso often when i let off and back on again or even when ive been off the power for a while....it sounds as if my dv is stuck open and theres little boost..then after a few seconds i can hear it close and bang...boost is back....i know it was doing it b4 i fitted the gauge so its not that leaking.....was wondering if there was anthing that controlls the vac system and would be keeping my DV open??? would apeciate help as its really anoying when i want the power and it leeks out of the DV.

 

[acidstrato]

the N249 system is where you want to look. the n249 valve is on top of the engine (on top of the coilpacks if you know were they are) right beside the alu charge pipe. there is a number of rubber vac hoses around here and one connects the n249 valve to the top of the DV. this one in particular could have blown off (or been left disconnected)

 

[B3NPM_Cupra]

Could it be a faulty n249? as i dont think there are any pipes off...i will have to check/change them all to eliminte piping

 

[acidstrato]

possible, but not very common to fail

could be a characteristic of the valve after all its a blow off valve...are you sure you set it up properly? it could be the valve needs adjustment. the pre load you set determines how easy the piston opens im sure!

 

[B3NPM_Cupra]

yea i thought that...will have a look at the dv l8r...i mite also try the standard valve now i have the gauge i shud be able to see if its doing it or not.

 

[beattie17]

Its your dump valve mate. When i ran a baileys atmos one it was exactly same as you described.
Say ur sitting on dual carriage way at 70 and you let off throttle a little bit down to 65/60,it lets air out and turbo gets dead laggy wen you go to accelerate bk upto 70. Hope that made sense

 

[B3NPM_Cupra]

yea it does sound exactly the same sound as the dump which makes me think it is the DV...i will have to check how much i have wound the spring down...mite well be too slack and the valve is opening far too easily.

 

[gavthelad]

possible, but not very common to fail

could be a characteristic of the valve after all its a blow off valve...are you sure you set it up properly? it could be the valve needs adjustment. the pre load you set determines how easy the piston opens im sure!

did you set it up correctly when you first installed it? I didnt get any with mine but if you read the instructions it says to wind the preload out fully and adjust until the spring rattle ceases, from there it should be just fine tuning really...

 

[B3NPM_Cupra]

did you set it up correctly when you first installed it? I didnt get any with mine but if you read the instructions it says to wind the preload out fully and adjust until the spring rattle ceases, from there it should be just fine tuning really...

I had mine wound fully out when i installed it but even then i didnt get any spring rattle so i just wound it in by 2 full turns i think....did ures rattle when you installed it...also is your dump quite a long dum sound or a short sharp one?? mine is quite long (compared to a normal blow off valve)

 

[B3NPM_Cupra]

still having the same issue.....looked at the valve that came on the car...was a forge but not a 007p..just a forge re-circ and the spring on that is sooooo much harder to press the valve open than on my split r...do you think i need to really wind my split-r in to stiffen the spring??

 

[acidstrato]

if that is the case then DEFINITELY!

and hope that sorts it

 

[B3NPM_Cupra]

Im gona try it today on my lunch...if all fails ill have to service the old valve and give that a try. willl miss the dump tho

 

[gavthelad]

yeah wind it in much more than that mate......youll notice that you get about a million turns on the preload adjuster, mines only about 4-5 from the bottom.

 

[B3NPM_Cupra]

yeah wind it in much more than that mate......youll notice that you get about a million turns on the preload adjuster, mines only about 4-5 from the bottom.

Thats good to know....was worried about winding it in too far and it not opening...defo be trying it at lunch!

 

[gavthelad]

the only problem i have with adjusting mine (although its set-up now) is my vac hose going to the top of the d/v is proper tight on the nipple, you cant adjust it without taking the hose off cuz you'll twist it.

 

[acidstrato]

my vac hose going to the top of the d/v is proper tight on the nipple, you cant adjust it without taking the hose off cuz you'll twist it.

Ya big girl!

 

[gavthelad]

..........

 

[B3NPM_Cupra]

the only problem i have with adjusting mine (although its set-up now) is my vac hose going to the top of the d/v is proper tight on the nipple, you cant adjust it without taking the hose off cuz you'll twist it.

i find it easyer to just take the main 2 hosses off! lol

 

[B3NPM_Cupra]

Okay update...problem now solved...not sure if it was faulty or not but ive done the n249 bypass tonite and everything is now honky dory...it must have been holding the DV open...neva mind all is now good....loads less clutter on the top of the rocker and DV is mega loud even tho im on standard boost!!

 

[gavthelad]

good stuff......get it remapped and its like a screaming wh0re!!