LEON CR fluttering boost problem

martin CR

Newbie
Sep 3, 2006
51
0
Hi, I have a 210 Leon CR, Revo st2, the car ran very well for three months and now there seems to be a boost problem, if you put the car in 6th gear at 1500rpm then full throttle, when the revs are around 2500-3000rpm the boost flutters up and down and the turbo note changes as its doing this. It only holds still when it goes over 3500rpm, also this is having an affect on top end power, at JKM's RR day the weekend the car was down to 242 hp instead of the usual 267, I have logged the maf and that is ok, and have tried a N75 from a mate's Audi TT with no change, if anyone has any ideas please let me know, cheers Martin:cry:
 

Mitchy

TTRS
Oct 12, 2004
2,310
0
Is your clutch holding?

Your putting a huge strain on the clutch by giving it full throttle at 1500rpm, especially in 6th where it will be kept there for a long period of time. Anything below 2700ish rpm full throttle especially in 5th/6th is not a good idea on standard clutch!

If its slipping, you obviously wont be holding boost correctly. You'll see an increase in boost, slip, decrease in boost, engage, normal boost.

Although you can normally detect a slipping clutch by looking at the syncro between rev counter and speedo. Rev counter looks weird and is not proportional to rate of climb to that of speedo.

I would have initially thought N75 valve, but if you have ruled that out i would then think clutch being at fault, especially if your abusing it at 1500rpm in 6th full throttle:blink:
 

claudefrog

Full Member
Oct 23, 2005
683
0
At home
www.reallymeansounds.com
I also have a very similar problem in my S3

1st 2nd and 3rd it pulls hard very hard throughout the whole rev range, put it into 4th 5th and 6th, the boost flutters terribly from about 3800 to 5400 then i get a sudden surge of power again from 5400, when rr;d i pulled 261BHP in a 3rd gear run, and 244BHP in 4th.

I have ordered a new N75 valve, but in all honesty I dont think its this doing it, as it holds ok in the first 3 gears

even the RR printout you can see the fluttering
 

bentaw

Revo'd LCR
Oct 1, 2004
1,067
0
Hampshire
Martin has an uprated clutch with LSD so its not his clutch his clutch is only 3 months old if that, my car does the same thing with regards to the boost but as of yet doesnt really affect the power i dont have clutch slip yet although i have the standard clutch, i pulled 242bhp and 301lbs ft of torque.

The turbo spools fine but just as maximum kicks in it pulls back and you can feel and hear it pulling back before continuing to boost again
 

bentaw

Revo'd LCR
Oct 1, 2004
1,067
0
Hampshire
Mitch also martin doesnt drive around in 6th gear at that rpm all the time but that is how to make the problem obvious to someone who hasnt seen it or heard it if you understand what i am saying
 

bentaw

Revo'd LCR
Oct 1, 2004
1,067
0
Hampshire
I think the more people that find this problem the better not being horrible but at least it isnt an isolated incedent what mods does everyone have who is having this problem perhaps we should start by seeing if any of the mods we have are the same and then this will give us something to go by
 

danieltm

Bit of Jabba magic!
Aug 26, 2006
796
0
Norwich
Well I have this problem too!! and i dont have any mods, i drive a LC 180. I just had it put on the rolling road and was told my dump valve has gone so i had a new one but still have the problem.. Been reading about it a lot on here but yet to find any good news. Thought about getting a N75 valve but people are still having the problem. I really hope someone out there have the answer!!
 

martin CR

Newbie
Sep 3, 2006
51
0
Is your clutch holding?

Your putting a huge strain on the clutch by giving it full throttle at 1500rpm, especially in 6th where it will be kept there for a long period of time. Anything below 2700ish rpm full throttle especially in 5th/6th is not a good idea on standard clutch!

If its slipping, you obviously wont be holding boost correctly. You'll see an increase in boost, slip, decrease in boost, engage, normal boost.

Although you can normally detect a slipping clutch by looking at the syncro between rev counter and speedo. Rev counter looks weird and is not proportional to rate of climb to that of speedo.

I would have initially thought N75 valve, but if you have ruled that out i would then think clutch being at fault, especially if your abusing it at 1500rpm in 6th full throttle:blink:
The clutch and flywheel is only two months old and is not at fault and I don't abuse it!!, I don't usually full throttle in 6th at low rpm but that is where the fault is, it is definitely boost surging up and down, I had a Revoed S3 for 3 years and know most of the common faults buy now, but have be caught out with this one so far.
 

martin CR

Newbie
Sep 3, 2006
51
0
I also have a very similar problem in my S3

1st 2nd and 3rd it pulls hard very hard throughout the whole rev range, put it into 4th 5th and 6th, the boost flutters terribly from about 3800 to 5400 then i get a sudden surge of power again from 5400, when rr;d i pulled 261BHP in a 3rd gear run, and 244BHP in 4th.

I have ordered a new N75 valve, but in all honesty I dont think its this doing it, as it holds ok in the first 3 gears

even the RR printout you can see the fluttering
I had a revoed S3 for 3 years and never had a boost problem
 

bentaw

Revo'd LCR
Oct 1, 2004
1,067
0
Hampshire
it appears this is becomming a common problem i dont think it is down to the code as it would have happened straight away surely not all of us have split hoses so i am at a loss at to what it could be
 

bentaw

Revo'd LCR
Oct 1, 2004
1,067
0
Hampshire
perhaps the diverter valve is sticking but then if this was the case and we all had serviced the valve then it shouldnt be doing it are we all running forges 007p yeah
 

martin CR

Newbie
Sep 3, 2006
51
0
perhaps the diverter valve is sticking but then if this was the case and we all had serviced the valve then it shouldnt be doing it are we all running forges 007p yeah
I thought you were working tonight mate?, when I get time I am going to blank off the DV and see if the problem is still there
 

bentaw

Revo'd LCR
Oct 1, 2004
1,067
0
Hampshire
The more i think about it the more i think it could possibly the diverter valve as another symptom i have is sometimes when i go to boot it there is no boost what so ever and then when i throttle off and go to boot it again boost is back so it is definetly something mechanical that is either sticking or failing and i am wondering if after 2 years of abuse that my diverter valve is dirty or stiking
 
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