another boost leak thread

lee01dg

lee01dg

New member
Joined
Jan 2, 2008
Messages
379
Well decided to rig up a boost leak detector for the twins and much to my suprise I have a major leak between the cold pipe and bottom charger. Now I rigged this thing up where I just took the air filter off and it slipped over the filter pipe nothing fancy. Question is how do I fix this, seems it don't matter how I twist the cold pipe or how much I tighten the clamp it still leaks terribly it wont even hold enough pressure to show on my detector guage. I'm sure that the flanges are flush but the clamp seems to have been tweaked some time or another but will still tighten up good. I'm thinking of making me a rubber gasket to go between the flanges and try that. Any thoughts? Truck still can make 50psi but should do more. Thanks Lee
 
what type of flange? surely not flat metal-to-metal v-band, right? you should have an o-ring v-band on the S400

you need to be 100% that the flange is seating properly. a lot of times when you install an S300 on one of these trucks, you may need to dress down the OD of the stepped portion of the discharge elbow because it won't seat all the way down into the turbo.

it wouldn't surprise me if you're having a similar issue w/ your S400
 
Smoking down the vband clamp will cause it to leak too. Once the v portion of the clamp spreads open it won't have any clamping force left.
 
Monkey chit!! You mean to tell me I've been running these chargers for over a year with the wrong flange on the s400. It is a v-band but the s-400 has no O-ring inside. The S-300 has no issues. You see the piping is source automotive and I ordered the charger from I believe forced inductions they said it would fit up perfectly and it does but it leaks horribly under boost. Do you believe the rubber will work and if not what do I do? Order a new comp. housing for the S400? From the looks of it it's not machined for an O-ring like the factory discharge elbow coming out of the S-300. Thanks, Lee
 
I haven't really smoked the V-band yet just good and tight where the charge piping is seated good. I believe Forrest has led me to the answer, now just a solution. Sorry guys I'm having to run back and forth to the shop, I will check the post later with my phone and get back to ya. Thanks for the help. Lee
 
Believe it or not the rubber gasket holds up pretty good stopped the leak for now, by the way the afc fittings are leaking air also when under pressure they are tight but a constant air flow is there. Are these suppose to do this? It leaks where my afc line goes in the afc housing, fitting is a 90 deg. 1/4 in. barbed fitting with a set screw to adj. boost pressure. Fitting was already in the housing when I got it. Is this plumbed correct? I'm still kinda new to the afc tuning and all. Sorry for all the questions. Thanks, Lee
 
That is an adjustable boost elbow with a bleed orifice. That is what you are hearing, the bleed. Take that sucker out and tune the AFC with shop air to allow full fueling at whatever boost pressure you deem necessary.
 
sorry but i smell a rat

a 500cc pump with a boost elbow on the afc?

more like a stock 180 pump with a 10 plate

i dont understand how you would tune the afc with shop air?

guess you could check for full travel but theres so much more to tuning it than that
 
DTanklage said:
sorry but i smell a rat

a 500cc pump with a boost elbow on the afc?

more like a stock 180 pump with a 10 plate

i dont understand how you would tune the afc with shop air?

guess you could check for full travel but theres so much more to tuning it than that
Click to expand...


The pump was bought off this site from another member I'm not a rat(thought that was a metaphor for a tattle tale), pump is what it is originally it belonged to Big Stu. I put the AFC on there from a different pump myself to try to control some of the low end fueling. If you don't know how to tune the AFC with shop air then what makes you believe it's a 180 pump with a 10 plate. How about some helpful knowledge if ya have any. Thanks Lee
 
There is no reason to get the o-ring, go get yourself some "Great Stuff" from NAPA, its an instant gasket and will take care of the leak quickly.
 
yeah I fixed the leak with a gasket and some yellow weather stripping adhesive to bond the gasket to the cold pipe put it together and presto no leak atleast for now. Thanks for your help though. Lee
 
CSM diesel said:
That is an adjustable boost elbow with a bleed orifice. That is what you are hearing, the bleed. Take that sucker out and tune the AFC with shop air to allow full fueling at whatever boost pressure you deem necessary.
Click to expand...

So you are saying replace the adj. boost elbow with a regular barb fitting and then tune in with shop air. I have it set now where it wont full fuel until about 40psi. But the spring inside is just not stiff enough. Will replace later on. Thanks for your help I'm gonna swap out some things DV's and injectors here shortly and see if that picks up on power any. Thanks, Lee
 
When you tune it with shop air you source must be regulated . People forget to put the word "regulated" in.
 
Yea, I take advantage that people know whats being talked about beyond the literal. People gotta search and read.
 
Don't get me wrong I was not trying to take jabs at anyone.
 
lee01dg said:
I put the AFC on there from a different pump myself
Click to expand...

my bad

forrest, what spring do you think he has in it now?

says he cant compress it til approx 40

i am thinking its a 215 spring since they are right around there just before coil bind
 
I have no idea what the afc came off of. I got it from a friend and yes I'm using regulated shop air. I still need to reset it because I was using the adj. boost elbow to regulate the pressure with and not the factory fitting and star wheel. Just seen it to be easier this way but apparently it's not working correctly b/c of the pressure leak it's creating. I'll keep ya updated on how it goes I haven't messed with it today. I'll get back on it first of the weak. And to top off my leaks both my blow off valves in the discharge pipe are leaking also. Both are set at 50psi but are not holding much past 20. Guess I'll tighten em' down some more also. Hopefully when this is all over I might just maybe gain a little. Thanks for everyone's help. Lee
 
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