[Babes]

I have power loss and heaps of backfiring between 3 - 4000rpms under WOT. Would a faulty BPV be the cause of this? The BPV is about the only thing I havnt replaced. Runs perfect under normal driving conditions but when you give it 3/4 to full throttle it misses and backfires like crazy until roughly just past the 4000rpm mark then pulls away strongly.

Any help appreciated

[Revolution Mini Works]

Quote: Originally Posted by Babes (original)

I have power loss and heaps of backfiring between 3 - 4000rpms under WOT. Would a faulty BPV be the cause of this? The BPV is about the only thing I havnt replaced. Runs perfect under normal driving conditions but when you give it 3/4 to full throttle it misses and backfires like crazy until roughly just past the 4000rpm mark then pulls away strongly.

Any help appreciated

zip tie your BPV closed for testing... that will eliminate or implicate the BPV

[Babes]

Jan im hoping you are coming to perth in march sometime, im slowly getting a growing list of folks together for your wicked tune!

[humph]

Sounds similar to the following threads. Hope they help

http://www.mini2.com/forum/john-coop...eleration.html

http://www.mini2.com/forum/engine-dr...tuttering.html

[DaFlake]

Babes, it does sound like the BPV.... I have (sitting in my car) a Detroit Tuned Bypass valve that I plan on fitting soon. You may want to take a look at a new valve, but the test that Jan mentions will tell you if it is bad or not.

Detroit Tuned // Detroit Tuned Bypass Valve

[Ant FR]

Quote: Originally Posted by DaFlake (original)

Babes, it does sound like the BPV.... I have (sitting in my car) a Detroit Tuned Bypass valve that I plan on fitting soon. You may want to take a look at a new valve, but the test that Jan mentions will tell you if it is bad or not.

Detroit Tuned // Detroit Tuned Bypass Valve

Can't see why a standardish car would need an uprated bypass valve. Seems a lot of cash considering you can adjust the valve closure on a standard OEM valve. i bought a new one a few weeks back and adjusted it myself no problem. I also believe the 4th iteration of the Bypass valve ( so makesure you buy the latest number) does actually have a different spring to the first ones originally fited to the 02 cars.

Plus from BMW the Bypass valve is £34 ie $60 seems silly to pay double for the detroit one,

[DaFlake]

Quicker response means quicker boost when you want and need it. I spoke to a few people that have them before I bought it and was told that it was well worth it. What I got from everyone was that the throttle response was much better.

It is a preference thing....

Lastly, BMW here wanted 80 Euro for the BPV...

[Ant FR]

yeha i relaise that, but a bypass valve works a bit like a dump valve or recirc valve on turbo cars, you will find springs are rated . if you use too hard a spring on a car not running enough boost the unit will not open, then you end up losing power the over way, thats what used to happen on the 1.8t Vag units, the recirc valve would remain closed or partially closed causing the pressure to find another weak part, on the VAGs it was the wastegate, but this could'nt vent without doing damage as it was an internal wastegate. Also most tuners here who do adjust the BPV do not mess with the spring settingts etc. I can only see it being required on a cur running 18psi or more ( which the one mentioned above is not)

Be interesting to see a tuners comment on this Detroit BPV, are there any tests to back up their claims

[roland2003]

Hi Guys, a bypass valve that does not fully close will not cause misfire at high load ,if anything the opposite as boost is lower than it should be, and therefore less demand on the items that can cause misfire at high load... eg plugs,leads, coil etc. (also try a new T Map sensor)
It is essential to have a bypass that does fully close and has no leakage around the butterfly.
Theres a lot of people putting in stronger springs, tieing them shut and now marketing a full aftermarket replacement. Yes early ones do suffer from broken spring in the actuator but even those by enlarge are 4-5 years old and the design has gone through various issue changes and appears to be excellent now.(with optimisation)
What does fitting a stronger spring etc do?
What it does is allow the bypass to shut when the pressure at the SC inlet (ie after the throttle but before the SC ) is lower . Or to put it another way it closes at less throttle angle.You can go even further and subject the bypass actuator to positive pressure (Ryefix mod). Or tie it shut.
What is the effect on driving with this type of mod?
Well if you press the throttle say 20% down ,the car accelerates faster ,hence some people raving about this type of mod. But at say 50+ % throttle there is no more left to give . In other words 100% is 100% whatever bypass preload you have ..,standard,uprated,pos pressure feed ,tied shut etc.
In effect the thottle becomes more of an 'on -off' switch ,...you lose the progression of the entire throttle pedal travel. -IMHO Not good....
Also the SC is choked (notice how much noisier it is with the bypass tied shut)....oh you will lose ecomony at light throttle aswell. as the SC is loaded when on a stock setup it 'freewheels' at light throttle.
Best Regards Roland GTT

[DaFlake]

Fair enough but I still plan on going forward with the valve. I'll let you guys know how I get on with it.

[Babes]

thanks for all the feedback folks, will be booking in for a new BPV. Even if that isnt it im sure I need a new one anyway.

daflake i like the look of the detroit valve too but my brother is coming for xmas in a few days and I want the car sorted quick smart as I have been raving about how wicked it is!

[alski]

so could a bypass issue be responible for my recent poor fuel consumption?

[DaFlake]

If it is stuck it could... Is the car running poorly? Also remember that in the winter the fuel mixtures are different and you will get worse fuel consumption.

[DaFlake]

Quote: Originally Posted by Babes (original)

thanks for all the feedback folks, will be booking in for a new BPV. Even if that isnt it im sure I need a new one anyway.

daflake i like the look of the detroit valve too but my brother is coming for xmas in a few days and I want the car sorted quick smart as I have been raving about how wicked it is!

and wicked it, is.... No worries, I was just pointing it out. The factory valve is not bad but I am a tinkerer. I want to see what the fuss is about.

[alski]

Quote: Originally Posted by DaFlake (original)

If it is stuck it could... Is the car running poorly? Also remember that in the winter the fuel mixtures are different and you will get worse fuel consumption.

no this is a 6 month issue, i assumed change from runflats to begin with, rolling resistance and profile to 215/40/17 with stickier avons to loose a bit, but also notice unburnt fuel smell as well in morning getting car form garage,
tank to tank has dropped from 340 miles to 260 trip from mid 30's to mid 20's

which will sound fair to most, but i drive like an old man as i like to keep smooth and also need a clean licence for work so often saw indicated range of 400 miles on re-fill

car at 26,000 miles at moment, service due at 28k

gtt 220 at 10k, wheels and tyres at 20k in may

[Ant FR]

maybe a sound thrashing may help. I know this sounds silly but bear with me.

A very good friend of mine who ia a Jaguar mechanic and now works on Zondas and Ferraris ( the lucky git) used to work for Fiat many mons ago.

Now he was always getting cars in from little old ladies who would say " the fuel economy is quite bad and the car feels a little slower than normal"

My mate would then simply take the car, bung some injector cleaner in, thrash it down the local dual carriageway, redline in all the gears and it would literally clear the car out. over the 20 mile run. the car would be cleared of all its carbob build up and oh he also reset the ECU to reset the adaptive learning etc.

They always thought it was something technical, but just they never drove their cars correctly i suppose. Nto saying that for you, but if you always poodle that could maybe be the cause, just a thought

[roland2003]

We recommend a yearly (12000m ) belt change ......Belt slip will lose power & fuel consumpsion as will a broken bypass valve spring.

[MINI-Morgan]

Faulty BPV, T-map sensor and possible slipping stretched belt under acceleration all adds up to poor performance. Check all the above and maybe an adaption values reset might make it run much better. Worked for mine.......and i've increased my idle by 50rpm so its now smooth too.

You will get worse economy with softer non runflats and smaller diameter/lower profile tyres. I'm running similar setup to you and noticed a good 2-3mpg drop on the motorway with smaller stickier tyres.

[Babes]

fuel consumption is fine and my belt is new too. Where is the T-map sensor?

[Revolution Mini Works]

Quote: Originally Posted by Babes (original)

fuel consumption is fine and my belt is new too. Where is the T-map sensor?

on the front of the intake manifold