mulot30th

Last summer we were running 12psi boost all day, but on our last ride last fall, boost was down to like 10 psi... so we thought it was a simple intake leak somewhere... no big deal...

This spring, when we first ran it, it was showing like 10 psi... (we still did not check the intake..) but it seems each times we run it, boost comes down and .. down and ... down.... now its between 7 and 8 psi at 6K rpm....

We just checked the intake by capping the inlet of supercharger and using the vacuum hose connected to intake to apply pressure on the entire intake system... it held 12psi with no more supply of air for like 30 seconds before slowly falling to 11psi ... so that pretty much eliminate any possibility of the intake being at fault...


So we are really wondering what happened :shock:

Got Me SOM

iTrader: (2)

check all the clamps to see if they are tight, probably a pipe is leaking or popped off at the bottom that you don't see.

andereck

Clean the air filter.

mulot30th

But how would it hold 12psi of air compressor without leaking then?

Gauge

iTrader: (3)

Loose belt? +1 for air filter cleaning.

mulot30th

I will check air filter... we never know....

Would a slipping belt have some symptoms other than that loss of boost?

Got Me SOM

iTrader: (2)

no. you will see dust. but vortech's spring loaded tensioner system is a very top notch. i've never encountered belt slip.

it is possible i guess. try the air filter , its gotta be something easy.

mulot30th

Okay I am in process of cleaning filter element (K&N) because it was a bit dirty (blackish).

Will let you know if problem got solved.

mulot30th

There is a little bit of black sooth around the supercharger's pulley....

mulot30th

Air filter is like a brand new one now (was a bit dirty...)

Boost is now down to between 7 and 8 psi....

at this rate... I wonder when I will start seeing vacuum at full boost...

just plain too weird.

GTOLarry

Belt slipping, rubber crumbs

mulot30th

Do I need another tensioner?

belt has only like 400-500 miles on it....


will try a new belt just in case...

Got Me SOM

iTrader: (2)

try the belt first, maybe try one size smaller if you can fit it on.

mulot30th

Its already really tight...

maybe its the smaller pulley... we installed a smaller (2.5") pulley....

so I guess we will have to live with the fact we need a new strap every 1 or 2 ride...

Inspector12

iTrader: (29)

I didn't see where you did anything to the Vortech stock recirculation valve? The stock bosch unit is prone to failing and bleading boost back to the inlet and increasing the temp and causes the type of boost drop you are describing etc... Get the billet one that is sold by Richart Racing or a Vortech race Bypass valve those bosch ones don't like anything above 10-11 psi although they have held for people they don't last.
jeff

mulot30th

The bypass valve is NOT recirculating air we vent it to atmosphere... and its so noisy (pppsssssshhhhhh sound) that we could never miss it if it were leaking anything significative...

will try belt first... then the bov....

mulot30th

Okay, we tried new belt, did not do it.

we tried belt dressing on it (the gummy stuff) and boost was up to about 9-10# (which is still far off the 12-13# we were seeing before) and... belt was disintegrated after about 2 miles.

So back with our old belt with the stuff on it, and boost is right at 9-10#...

I understand it may slip, but why cant we stop it from slipping anymore while it was no slipping back when we got 12-13# of boost?

Am I just too idiot to understand something?

DeltaT

iTrader: (5)

I have seen issues with different pullies that I believe are caused by different pulley surface treatments, like anodizing vs. hard anodizing. I have a 3.12" Vortech pulley that has very little slip, but I have another pulley from ASP which is a 2.85" one and it slips like crazy. I looked at the ASP pulley under a microscope and the finish is a lot smoother than then Vortech. So I'm just not going to use it, ever.

Have you considered the Vortech Hi-Traction pullies? They are hard anodized. I just got one for my T-trim but have not tried it yet, but the surface is noticeably more grippier.

Jim

Got Me SOM

iTrader: (2)

is it really hot where you are now? my boost will decrease when it gets hotter out. was it cooler when you were making more boost?

mulot30th

not very hot, I am in Quebec in Canada.

My 2.5" pulley is an ASP pulley... so I guess its a smooth surface...

I dont know if sanding it would work?