need help with supercharged r32

[silvr6arrow]

thanks for your time, I have an 04 r32 with the stage 1 vf supercharger kit. shortly after i bought the car the charger was leaking oil, so i took the charger off and sent it to a place called supercharger rebuilds and had it rebuilt...at only 1000 miles later the bearings shattered and sent the impeller into the casing and broke the impeller. I then sent it back to the company and they recommend they upgrade it to a g trim. It was origianlly a f trim. They went ahead and bored the charger out and put a g trim impeller in it. Ever since i have it back on the car, between 2500-3000k rpm the car would blow off the boost. It sounded as if the diverter valve would open prematurly and dumb boost too eaisly. I replaced the valve that came with the kit with the exact same one and it did the same thing. At the time i was sick of dealing with it and decided just to drive the car how it was. Now i am sick of not being able to drive the car around in first or second gear threw town without it bucking and careing on. Today i was informed to replace the plastic valve with an apr r1 diverter, some people thought the plastic one could not hold the couple extra pounds the "upgraded charger was making. needless to say the apr did not fix the problem. i did some further investigating and this is what i came up with...I beleive it has nothing to do with the diverter, if i take the diverter off and plug the 2 ports it still does it, what is happening that is between 2500-3000rpm the car pushes boost back out of the airfilter, if you rev the car to 2500-3000 and put your hand near the maf without the airfilter on it will push your hand away from the airfilter. You can feel quite a bit of boost coming out the opposite way...The only thing i can come up with is that the boost is somehow traveling back threw the charger and out the intake side of it. any help would be greatly appreicated. thank you

[youlostme21]

More horror stoies are coming out of Superchargerrebuilds.com lately. I got screwed by him too.
How big is your DV lines? and how far away from the charger is the MAF? Does it do it just cruise or when your on the throttle too?

The charger is pushing air and witht the throttle closed it has no where to go so it has to go through the DV but if it dumps to close to the MAF it screws up the reading and the ECU freaks out.
I had and Issue running an aftermarket DV cause it wouldnt open at cruise/low boost and it would cause back pressure on the impeller. Hear alot of mustang guys having issues of the impeller nut backing off cause of this too.

[silvr6arrow]

The maf is approx 12in away from the charger, it is the setup that came with the kit, nothing has been motified there, the valve hoses are i would say 1.5 inches in dia. the size that fits snug on the dv. it dumps the waste right back into the intake side right about the maf. This happens with or without the dv on the car....superchargerrebuilds

[silvr6arrow]

also it only notibly does it in 1st or 2nd gear when your trying to go threw a town or drive slowly around a parking lot, if you put it in 3rd gear and lug around it will not do it, it also runs fine at wot

[mk4vrjtta]

first, the DV is suppose to stay open all the time, until you get close to 0inhg. and you said if you plug the 2 holes it still blows air out of the charger? so instead of sucking air in it's blowing it out of the inlet?

edit: maybe he gave you the wrong impeller since some superchargers are clock-wise rotation and others are ccw

just saw you said it runs fine at WOT. so nevermind about the wrong impeller

[youlostme21]

if you plug the DV lines the boost has no where to go but backwards out the charger so that makes sense. Do you have a stock style DV back on the car now? I think the MAF is too close. What kind of boost were you seeing before and at what rpms compared to now?

[silvr6arrow]

it does it with or without a dv valve, it does it with the oem sytle and with the apr r1... I have roughly 1 pound more boost then i did before i had it rebuilt. today i made sure the throttle body was alligned and also took out the valve inside the front of the intake that is vacum activated, just to make sure that was working right, it does it with or without that in also... if i remove the boost tube and run the car, the car runs fine. I did that to look in the throttle body and it is opening fine...im not too sure what to look to next?

[youlostme21]

With it disconnected and the car running does air pull/push the right direction out of the charger? Wondering if it is an impeller issue like stated earlier...
Nothing else changed from before and after the rebuild?
Did you clean the MAF and throttle body due to the leaking oil?
Something is wrong... Now the fun of finding it, right?

[silvr6arrow]

It pushes air back out threw the airfilter even without the dv. Nothing changed except what they did to charger its definitly spinning the correct way because if you take the boost tube off the tb there is plenty of boost there. Maybe i should buy a new boost guage to make sure im somehow not getting way to much boost between 2 n 3000rpm if i am getting too much it could only be at certain rpm

[silvr6arrow]

ok so i installed a boost gauge today and this is what i came up with

at idle 0lbs

2000rpm 2lbs

If i rev the car between 2000-3000 the lbs fluctuate between 0-5lbs ( this is at the point where is surges)

at full throttle it spikes at 9-10lbs, from my understanding this is too much boost for a stock engine at these rpms...however it does run perfect up top and i pulled the plugs and they look perfect, not lean at all

[mk4vrjtta]

ok so i installed a boost gauge today and this is what i came up with

at idle 0lbs

2000rpm 2lbs

If i rev the car between 2000-3000 the lbs fluctuate between 0-5lbs ( this is at the point where is surges)

at full throttle it spikes at 9-10lbs, from my understanding this is too much boost for a stock engine at these rpms...however it does run perfect up top and i pulled the plugs and they look perfect, not lean at all

there should be vacuum at idle and even when youre revving it up, unless you really step on the gas for a second

[silvr6arrow]

How much vacum? I have none

[silvr6arrow]

Btw i have my boost guage in the charge pipe right before the tb is this correct or should it be in the intake

[mk4vrjtta]

Btw i have my boost guage in the charge pipe right before the tb is this correct or should it be in the intake

boost gauge should be hooked up after the throttle body. most people T the vac line from the fuel pressure regulator

[silvr6arrow]

ok, this morning i went and bought a new south boost gauge from ap tuning. I hooked up the gauge in the line for the fuel pressure reg. this is what i came up with

at idle i have 20 vac

if i rev the car up quickly it goes up to 5lb boost

if i slowly rev the car to 2-3000rpm where it acts up, the gauge stays in the vacuum side 20-15

[mk4vrjtta]

ok, this morning i went and bought a new south boost gauge from ap tuning. I hooked up the gauge in the line for the fuel pressure reg. this is what i came up with

at idle i have 20 vac

if i rev the car up quickly it goes up to 5lb boost

if i slowly rev the car to 2-3000rpm where it acts up, the gauge stays in the vacuum side 20-15

sounds normal. if you look INTO your intake pipe there should be a smaller pipe where the air flows from your diverter valve towards the supercharger. this is still there correct? if its not then that could be the problem. this would cause alot of turbulance right at the MAF and would probably cause you to feel air coming out of the filter since it wouldnt be directing it towards the compressor wheel.

[silvr6arrow]

got it fixed!, dont ask why but i decided to install a second dv and now the car runs great, the only reason i can come up with is because the car must have been making too much boost at that rpm and it could not get into the engine due to the throttle body being only slightly open at that rpm, one dv must not have been enough to pass the boost by at idle and low rpms thanks for the help

[youlostme21]

nice! glad you figured it out.

[92jetta9a]

Did you get the billet impeller with the scroll modification?

This netted a full pound of boost?

Just looking for a little feedback on this option of a rebuild.