boost loss

[andieleon]

i have problem??
i noticed when i took my car out for a test after i put in my boost gauge that i boost a healthy 0.7 0.75 at first for a while and when i was on my way home the boost dropped to 0.5?? i have a lc with induction and n249 bypass, can anyone give me some ideas to what it might be, i did find a thread on the forum but it was talking about diesel engines not petrol so didnt no if it was the same???? please help guyss

 

[adam cupra 20vt]

Well 1 bar is 14.5? so 0.5 bar is 7.25 and thats not limp mode so i'd say you have a leak or a faulty MAF or N75 valve?

 

[andieleon]

how would i check to see if i got a leak?? could it be where i done my n249 bypass

 

[adam cupra 20vt]

Umm it could be anywhere to be honest....You may have knocked something when putting boost pipe in?

 

[andieleon]

but why does it boost to 0.75 then just drop after a while wouldnt it do it all the time if i had a leak??

 

[Damoegan]

What do you mean by 'drop after a while'? As in higher up the rev range?

 

[jake]

not always, we had a car in with a leak where it only happend sometimes,

 

[adam cupra 20vt]

but why does it boost to 0.75 then just drop after a while wouldnt it do it all the time if i had a leak??

I have no idea thats why I said it could also be something else like a faulty n75 valve

The gauge might not even be accurate and you may well be over reading and in limp mode?

Have you tried it again to see if its ok now?

 

[andieleon]

no it will boost at 0.75 and then hold at 0.7 for maybe 5 mins while driving around and then after that it will start boostin 0.5 holding then at 0.45 ?? surely if it was a leak it would be boosting 0.5 all of the time??

 

[Damoegan]

What DV do you have?

 

[andieleon]

well im going to go check around where i done the n249 if i cant see any leaks or cracked pipe should i start thinking about the n249?

 

[andieleon]

i have standard dv

 

[adam cupra 20vt]

well im going to go check around where i done the n249 if i cant see any leaks or cracked pipe should i start thinking about the n249?

If you can't find anything it might be worth un doing the bypass and trying it.

As said if you have standard dv you could have split diaphram

 

[Damoegan]

i have standard dv

Could poss have a split in the diafram. Might be worth seeing if there is someone who live close to you who would let you try there's, just to ruel it out.

Failing that, try checking all the boost pipes for splits, especialy where you have took the feed for the boost gauge off and even the pipe to the boost gauge.

 

[andieleon]

what is the diaprham

 

[Damoegan]

what is the diaprham

Its a part in the standard dv that is known to fail.

 

[andieleon]

well i could hear that there was a problem before i did the gauge so i dont think it is that because i noticed less noise from the dv a few days before as if i was boosting lower?? i have just checked the pipe work and there is no splits or cracks in any of it that i have tampered with??

 

[andieleon]

right i just went back out in it and had no problems it boosted to 0.8 and held at 0.75 in all gears up to 4th (not enough road to go faster) so it is just now and again!! i was going to buy a split r dump valve maybe this is the time to purchase it

 

[Damoegan]

I'd recommend the 007p over the split r.....

 

[adam cupra 20vt]

Me to....