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After hearing how quiet the JR m45 SC is, I have been playing with my duel TB set up to quieten down the charger a little, I think the Cooper S charger is a little louder than the JR anyway, but the problems I am having are:

1. If I have the pre-charger TB cranked open very slightly more the the post charger TB it all works well but the charger is very loud.

2. If I close the pre-charger slightly, the charger is much quieter but the few silicone elbows that I have either side of the I/C are sucked in (neg boost) and the idle/initial (slow)acceleration is poor.

I have tried miniscule adjustment but I cant seem to hit a happy medium
, the pre charger TB is literally a butterfly leaver, everything else has been removed. Any Ideas?

Barry
 

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After hearing how quiet the JR m45 SC is, I have been playing with my duel TB set up to quieten down the charger a little, I think the Cooper S charger is a little louder than the JR anyway, but the problems I am having are:

1. If I have the pre-charger TB cranked open very slightly more the the post charger TB it all works well but the charger is very loud.

2. If I close the pre-charger slightly, the charger is much quieter but the few silicone elbows that I have either side of the I/C are sucked in (neg boost) and the idle/initial (slow)acceleration is poor.

I have tried miniscule adjustment but I cant seem to hit a happy medium
, the pre charger TB is literally a butterfly leaver, everything else has been removed. Any Ideas?

Barry
does the TB still have the idle screw on it....if so you could just adjust this to let more air past instead of cracking the TB open or a combination of the the 2
 

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you want the inlet manifold one completely closed when shut.. that should stop the hoses collapsing. then the tuning is done with the pre charger 1.

It's very fine adjustments though to cancel noise out... you can shut both really but you need to shut the inlet one first. Then you should have no in or out for the air in the pipe.. but positive pressure will get out through the pre charger throttle if there is too much making a vile racket.. this can be cured with a dump valve
 

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Discussion Starter · #5 ·
Where are you taking your idle air from? Take it pre-blower throttle and you shouldn't get a vacuum in between the blower and stock throttle.
Idle air is taken from a mini filter direct to the inlet TB...........
 

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Discussion Starter · #7 ·
Looks like you were right Nick, the inlet TB could not have been fully closed
I loosened off both TB cables and TB adjuster screws and started from scratch, the SC is now quieter, no neg boost sucked in hoses and no performance lost. I am getting a 'sucking noise' from the air filter at idle and when I initially pull away - which is nice


Cheers Guys

Barry
 

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I have a whooshing type noise which seems to be pressure blowing back through the air filter when i come off the throttle (changing gear etc), is this normal? My pre charger tb is not fully closed off when shut. If i close this as well as the inlet tb, what happens to the pressure? How & where do you stick the dump valve?
Rob
 

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Discussion Starter · #10 ·
Are you sure its boost you can hear? I had a similar noise when I changed to the 11% reduction pully (you have?) it turned out to be belt slip on gear change from high revs, it sounds like boost leak. The belt needs to be a little tighter with the smaller pulley, try it Rob just to discount it. How is it running other than that?
Barry
 

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Hi Barry,
It does it whenever i am in boost, whether 1psi or 7psi. I have tightened the belt today anyway, as it was a little slack. I will check it again. can you see it happening when revving from under the bonnet?
Well chuffed with the result though, getting about 7 psi. Need to fit a doorknob to my seat now.....something to grip onto!
 

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Discussion Starter · #12 ·
Nah, I couldent see the belt slipping under the bonnet, If tightening the belt doesent work then it sounds like you need to calibrate your TB as I did, give me a bell if you get stuck bud.

Barry
 

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The belt was indeed slipping on overrun, i could actually see it flapping! I have now gone as tight as i dare, with the belts almost touching. Might have to buy a smaller belt. The good news is though, i hit 8psi tonight on the way home from work, only managed 7 before
 

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Discussion Starter · #14 ·
The belt was indeed slipping on overrun, i could actually see it flapping! I have now gone as tight as i dare, with the belts almost touching. Might have to buy a smaller belt. The good news is though, i hit 8psi tonight on the way home from work, only managed 7 before
I had to go for a smaller belt and extend the travel of the right (adjustable) pulley on the tensioner - works great
Glad you are up and running Rob.....
Barry
 
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