bmwm3turbo

no smoke ,only 30psi and soap water
maybe the leak was to small last time i tried it

T9ja

So this could result in lost of boost? Mine do bounce on idle.

Hulk

Yes if the tensioner is moving too much at idle I would change it

DVC

What Hulk said.

Also, put the front engine cover on (the part with the star logo that falls off) and make some WOT runs. Check the bottom of the cover for a trail of belt dust. Telltale sign the spring is weak.

chawkins2001

Damn you dudes are smart

T9ja

Any suggestion for a replacement part? Stock or aftermarket?

T9ja

This is what mine looks like on idle.

Hulk

Not moving that much, i think you are fine. mine was jumping around like crazy
Only replace with stock

sexyxe

I am on stock pulleys and see just over 11psi. I also get a decent amount of dust/oil on my engine cover, and no belt squeal. I am running a BWK though.

DVC

Just some things I've noticed WRT to slip....take them or leave them A "decent amount of dust" on the underside of the cover is belt slip. It won't necessarily squeal.

If you happen to be reading boost though the OBDII port, the data rate can be slow enough to miss the "dips" in boost. The BWK is not a band-aid for a failing tensioner. For reference, I have the 84mm pulley and zero belt dust on the cover.

C32owner

This is very interesting. So should a normal everything perfect in the motor boost curve should be linear, let's say starting at 5psi and then builds up to 12psi at redline as the motor spins up... My boost definitely is up and down on the way to max. Any one that can share a nice curve of how it should be?

Hulk

How are you measuring? If its obd then you can not have other parameters at the same time because the refresh rate will be too slow. Also if it's going up and down by 1-2 pounds that's not good but if it's .1 or .2 that's ok

seanol

I have dyno'ed a number of supercharged engines. What I see with screw type compressors is a curve that looks very flat with a slight rise in the middle of the curve. Torque starts high and then drops. Boost curve is very linear.

On centrifugal superchargers you will see boost rise with RPM. They will start low and go up with RPM. Boost curve goes from low to high in an increasing manor.

chawkins2001

I am not sure how accurate that boost graph is now. I logged boost through my dashdaq with a sensor mounted in the surge tank, and it was straight as an arrow.

seanol

It depends on your sampling rate. I would go with the one that has a higher rate. Dyno operator should know how often they are sampling. Where did they get the signal from?

chawkins2001

Dyno signal was from OBDII bro.

Mine is from zeitronix directly into surge tank and I don't know the rates.

seanol

Then I would trust your source over OBD2 as sampling rate will affect it. I'm sure you have a higher rate on the zeitronix.
If you can get the Dyno file into excel you can plot your Data against it and see. Plot against rpm.

Hulk

Zeitronix boost sensor over the obd all day long bro

chawkins2001

Sorry just saw the post on idler, mine does not move at all on idle bro.

Hulk

That's good don't waste your money on a new tensioner

SuperChargerE55

What you use for obd to meassure boost then?
Torque DashCommand does these work I mean are they trust worthy monitoring boost?

Hulk

I use the boost sensor from zeitronix, real time and no lag
If you must use obd do not use more than 2 parameters or the refresh rate gets bad and lags

SuperChargerE55

Thank you will remember that.
The Zeitronix boost sensor sound interesting and thread aswell.
Super thanks will remember that 2 parameters

SuperChargerE55

1 question with Torque I can change it to 2 decimal
Is that the same?
There is a lot of good stuff boost can be adjusted
https://torque-bhp.com/wiki/Boost_Adjustment

GatorMB

Hulk is stating, (Do not utilize any extra resolution from the CAN bus of the car).

It will slow down the actual Fr (resonant frequency) degrading bus speed and performance.

I think an AEM Wideband with a piggy back input would be more desirable.

Thoughts, Gator