Ok....system is complete and I drove it home. First, here are the problems at hand:

1)BOV - It is sitting too close to the MAF and causes major turbulance, like right next to it. Idle is rough and eventually dies. I have to keep the a/c on so the car doesn't stall. Around ~2400rpm the car gets major turbulance, all other RPM seem to be normal. We are going to bypass the bov air back into the S/C to fix this. The MAF sensor sits under the blower and the BOV is right before it. So it goes BOV --> Maf --> Throttle Body.

*Note - The car is UNGODLY loud becuase of the BOV. At idle it's significantly louder then my V1 setup. We pinched the BOV line and it got REAL quiet. The BOV sounds awesome while driving but it sounds horrible at idle, like that fork in the fan noise. The blower itself is noisier then expected, but mind you the GTP's blower sits in the engines "valley" so it's noise gets masked. Under WOT the blower seems to be making the pretty noise that i'm in love with. Shifts are REALLY jerky becuase of the f#cked up bov/maf relationship I assume.

2)Fuel Pressure. I see about 6psi at 2000rpm, and my fuel pressure shoots to like 97psi right away, accordingly with the Boost. BUT, as the rpms increase, the FP slowly and gradually decreases, which is very weird. Also, 97psi seems way too high for 6psi. What do you guys make of this? I have not redlined or even gone past 5000rpm.

It's soo incredibly loud right now b/c the bov its sick. Not healthy sounding at all.

3)The belt. It was shredding on him a little, so he tightened it up as tight as he could. It doesnt cover the idler pulley by a long shot, and doesnt sit on all the ribs of my vortech pulley.

The power is a huge difference, although my main focus was on not f#cking my car up, and why the FP was acting the way it did. Why on earth would it be doing this? My setup is: 8:1 FMU disc, S-AFC (not set), AEM FPR set at 36psi, and Walbro Hi Flow fuel pump.

HERE ARE THE PICS!






You can clearly see the BOV setup in the one pic, and how my belt is setup. Help..

 

The BOV should not interfere with the MAF because it is not ejecting metered air, even if it is close to it.

 

Yeah, like on_alert said, that doesn't really make sense. If the BOV is letting out air that that MAF hasn't yet "seen", then you should be just fine. I don't see why how close the BOV and MAF are should matter.

Makes sense. If 6psi is full boost, you should see full FP at that point. Is your boost slowly falling off as you get closer to the redline?

Can't quite picture what you mean, but that doesn't sound good at all.


You're going to have to dyno ASAP so you know that you're not going to do any damage.

 

Why is there a pic of the J30A motor? Anyway...Can you possibly get a soundclip of it? Im sure some1 can host it. I have never come across anything like this, so I dont even know were to begin I still say your nuts, but good luck getting the problems resolved.

 

Update:

First of all, my Check Engine Light is on. Could resetting it fix all my problems?

I just went to drop off the photos at publix for development, and have come to the conclusion that the car is not driveable.

First, I got near redline. I see about 7-8lbs of boost, and didnt really notice it falling off. The power is weird, sometimes it seems slower then my vortech and other times much faster. It's weird. I don't think my overall acceleration can be judged just yet though, becuase something is obviously wrong. As for sound, it sounds healthy, just like a roots blower should. I would be extatic about how it sounds, but i'm soo p!ssed off now it's not even funny.

The car JERKS into gear, if I let off the throttle 10% after engaging the car will JERK. Shifting gears brings about a JERK. The car is HORRIBLE to drive. Even the most experienced shifters would go CRAZY. It's like the ECU is nuts. The idle is rough even with the A/C on it went to 300rpm and shoots up to 1000 almost dying. The sound is ungodly loud at part throttle. At WOT it sounds healthy and cruising outside of vaccum is normal. Otherwise its sick. It's not the kind of attention I want. It's horrible.

To top it off, Tom says he won't be able to bypass the BOV 'till monday, which means im S.O.L. becuase I refuse to drive this thing. It's soo messed up.

I noticed that the fuel pressure settles to around 85-90psi. The car feels unusually slow at some spots and a lot faster in others....but it's akward becuase some runs it will take off and others the RPMs just seem laggish, like something is limiting how fast my car revvs.

On a "good" note, In second gear I get major power around 2000rpm, and if the tires don't break loose I get insane torque steer. It's not violent, just really pulls. The car hauls @ss at certain spots, but definately dissapoints at others, which I don't believe is it's fault.

Photo's should be coming around 6pm.

 

Sorry about earlier, it's just so hard to believe man!
Hope you get all the problems worked out. Imagine all the problems stillen had when they first S/C the max and hal had when he went turbo, so it's to be expected. You have had alot of faith so far, just keep it up.

 

The SES is obviously pointing out something is wrong. Im not there so I cant really point anything out man, but do as ejj says. Get it to a dyno and find out whats wrong. There should be no lag.

 

BTW, when we plugged up the BOV and/or pinched the line, the car got A LOT quieter, and healthy sounding, like it should sound. So therefore I am 100% sure that the BOV is the main culprit of the obnoxious sound, and pretty sure its why the car is f'ing up soooooo bad.

 

congrats on getting it up and running... I don't know **** about why it's not running well, but I'm sure there are plenty of folks here who can figure it out.

Did you check to see what is tripping the SES light?

 

I'm about to go run the ECU for codes, I doubt it will help though.

Here is an email I recieved from the guy who sold me the blower:


I dont know what you are doing with the shaft but if you are adding length
extending out from
the nose of the supercharger this will be adding extra axial stress to the
bearings and the nose is
already extended out, that is why there are many gussets for support.
Also how are you putting tension on the belt? the gtp used autotensioners
and i dont know
what kind of tension these apply but if you are running manual tension you
will be able to apply
more tension causing more stress on the bearings.

Just some additional thoughts i had after i sent you the previous e-mail.
Jeff.

 

Then get rid of it asap Ive never heard of a Roots type S/C hooked up with a BOV. Your going to have to do w/o one. The GTP's are fine w/o it
Come to think of it, I dont know how your going to tune the Ecu to counter that. Now I dont know if this is also happening right now but it just reminded me of when a friend of mine put a BOV on his GTI 1.8t. Now that motor is set up in a way were if the Boost suddenly leaves (from the BOV) the fuel is still going to me there to match the air going in between the shifts. SO every time he let off to shift, he would get a little black puff of smoke out the exhaust. His BOV was making the motor run pig rich. This could also be happening on your setup, I dont know how the ECU is going to tailor to this but its also another possibility to look into. I havnt seen a roots type with a BOV man. If there is some1 please correct me. I still stay get over to a dyno, make sure they hook up a wideband o2 and see whats really going on.

 

are you saying that you didn't think about this BEFORE the install?? Thats kinda obvious I'd think.

 

ECU readout came back negitive (0505) and resetting it helped nothing.

 

try a dsm bypass valve or something similar, also what type of fuel setup are you running? you're gettin full boost off idle, so of course the fuel pressure will be higher.

steve

 

Finally PICS are up! Hopefully this will give you guys a better understanding...the first pic you can clearly see the BOV b4 the MAF

 

If the original GTPs didn't come with a BOV as HITMAN said, I recommend that you bypass it with a straight piece of piping. Or if it came with a re-circ. bov, replace it with the Vortech BOSCH unit. As far as your FP pressure goes, you will probably need to upgrade to a Vortech S-FMU, or Cartech similar unit. For seeing such lower boost at such a low RPM at the FP (almost 100) you are running way rich. The boost bleed (and max FP setting) on the Vortech S-FMU will help you out with this dramatically. And, as far as you loosing FP as you go through the RPMs, it sounds that may be an unsecured vacuum source......

 

Not bad, thats one loooooong M90 snout Dude...you better get an MEVI to top that thing off

 

Did you try adjusting the screw on the bov? How much vacuum are you getting at idle? Maybe you can adjust the screw so the valve doesnt open at all (to similulate removing it like hitman said).

Throw a smaller disc in the FMU. And check all the vacuum lines.

 

congrats on getting the pics up.. i put the bullsh*t flag down now, that's all you had to do. you didn't have to get all antsy, tons of people talk about nonsense projects and nothing ever comes of it, it's nice to see you came through. good luck with the issues

 

after reading all the posts now to see if i could add anything..

i also wanted to know your vacumm readings, at cold idle and at warm idle (basically just after boost or doing driving under no throttle).

also try adjusting the BOV to nearly closed, or just close it if you can (pinch the line completely) and drive the car.. as mentioned you should do this on a dyno though and see if a bunch of these issues go away.

why run a BOV if the setup is not designed for it???

it sounds like my turbo would still own jo0 by the way

 

Craig,

the pics look nice...good luck with getting the issues sorted out.

Nupe

 

I've never heard of a roots blown vehicle with a BOV but that doesn't mean much since I'm not into roots blowers or the cars that have them really.

Anyhow heres this, for what it's worth. the purpose of a blowoff valve is to prevent compressor surge when the throttle plate is closed (vent the air that is about to jam up in the compressor into the atmosphere instead.) Being as I've never seen or heard of a roots car with a BOV, that makes me think that a BOV for a roots blower is unnecessary. Maybe the design of eaton blowers is such that compressor surge doesnt occur, or doesn't harm it. So my basic though is this, the BOV is an unneeded part, much like a boost controller on a supercharged car, it's just some accessory which you could put on there but would serve absolutely no purpose whatsoever... I say try it without the BOV entirely and see what happens.

 

I know we can't use the standard bypass valve, becuase of where the thing is positioned on the blower. We have to use the BOV and bypass the air via it. It would serve the same purpose, though, and should work just as well.

 

It's not the screws or anything that's the issue, because when we plug the BOV up the loud shreek is gone. Or maybe I don't understand what your saying? Vaccum is normal, 17-22 on average.

 

I think he is saying that you shouldnt use a bov on your setup.

 

 

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123456789

 

Keeping ****ing around craig, get the POS on the dyno and get it tuned before it goes boom!!

Oh yeah, and depending when your getting your **** dyno/tuned, ill probably be there getting mine dynoed , just lemme know. Setup looks sick.


Eric

 

Here let me help you

j/k

 

Hope everything works out.

 

Congrats, the worst is over and now you just have to get all the kinks out of it to get her running properly.

1.) Setup a bypass line - screw the BOV. Make sure that you do this correctly. I've been up your stalling car/weird shifting/MAF issue alley before when I did my V2's CAI - pointing my return line towards the MAF as opposed to away from it (towards the blower/up the pipe) made a night and day difference - you're screwing with airflow readings and thus the car can act punchy for a bit after it nearly stalls and pops into gear. No big deal.

When I had it done all wrong, my car would lose all power when I stepped on it, and then smash into gear. Sometimes it would stall. Also the car would be faster at 40% throttle than at let's say 60% throttle...it's sort of like what you get if you have a busted MAF.

2.) Get a new belt - Goodyear Gatorback hands-down.

3.) Might want to chatter with the makers of your supercharger. Go here and browse around/submit a form : http://www.automotive.eaton.com/prod...ercharger.html

 

First of all, congratulations on a nice looking setup, Craig. From the pictures it looks well implemented, and the problems you are having are most likely due to a few details that need to worked out.

I think the driveability problems you are having are due to the blower, bov and maf being so close to each other. The blower is pumping a lot of air at low speed (what you wanted, right?). Not only that, but it is sending pulses of air down the intake rather than a smooth flow that a centrifugal compressor produces. The bov should be able to vent off any extra air the engine doesn't need, but I think two things might be happening. One is that the bov is set too tight (or is not large enough) and is not venting enough air. This results in a constantly pressurized intake tract that makes the engine very sensitive to throttle movement.

Second is the pulsing nature of the air flow along with the maf being too close to the bov. There may be enough of an oscillatory flow in intake tract to confuse the maf. In other words, air is pulsing back and forth in the maf, making it think there is more air flow into the engine than what actually occurs (since the maf doesn't care about airflow direction), especially at low speed. This will make your car run rich. The cure for this is to make sure the bov is venting sufficient air when not boosting, or, position the maf before the blower (in which case you will need to run a recirc hose from the bov to a place between the maf and blower.

Another issue is throttle placement. Corky Bell writes this in Supercharged!:

Throttle placement

Because the Roots is a fixed displacement supercharger, the throttle is customarily mounted at the compressor inlet. Without the design complexity of a bypass valve, this becomes a necessity. If the throttle were downstream, closing it would cause a buildup of pressure between it and the supercharger, forcing it to a stop and wreaking havoc with the belts. A technique for blowing into the throttle with fixed-displacement superchargers has been developed but is not yet available in the aftermarket.

Certainly, in many circumstances, including a bypass valve will be easier than relocating the throttle. However, the closer the throttle is to the intake valves, the more crisply and responsively an engine will run. It is currently popular to use the bypass, yet leave the throttle in front of the blower.

 

Seems to me that the best way to cure Craig's problems would be to re-located the MAF before the blower and run a recirc valve.

If nothing else, it will remove this whole BOV-MAF mess as a potential part of the problem.

 

i was wondering about that throttle body placement thing i couldnt remember where the tb is on a gtp but i bet its at the blower inlet so the above stament makes the most sence move the MAf infront of the blower to get it away from the turbulace and run a recir hose but you will have to keep the blow off valve in there or somthing will go boom because where else is the air the blowers pushing at idle going to go.

 

Good job craig.

Way to be different

 

thats crazy mang....

good job you came through......

 

I think we should ask for redmax007's assistance on this since he currently owns a GTP with the same blower. Maybe he can add something.

 

Jer, your explination seems to apply to me. The acceleration seems really funny like that. Sometimes at WOT it would feel faster then other times, in the same RPM. Wierd.

Guys,

Beside the fact that the BOV is probably screwing up my car, what about the horrific noise? It's soo horrible, that my mom could hear me in her car with the windows up as I went across the intersection. I mean, it doesn't even sound good, it sounds sick. It's horrible. When the BOV is plugged up, it gets a lot quieter, but the blower still only sounds normal IMO under WOT. Even if I loosened the BOV to release sufficient air, it would only get louder. You don't even understand how bad it sounds, I can't even drive the thing. The BOV releasing air is about 3 times louder then on my old setup, and this is WITHOUT the horn. I mean, it sounds badass while driving, but for some reason the BOV effects the overall loudness of the blower. I'm almost convinced of that. Bypassing the air will quiet the system down like 5x. The ONLY way we can bypass the air is using the BOV, and I guess recirculating it back into the blower. The bypass valve on the blower is on the other side of the blower and is not accessable.

 

Just bypass with whole BOV with a straight piece of piping, plug that vacuum line, and see what happens....

 

I had my buddy who is a GTP guy check out this thread. 1. get rid of the BOV. 2. As someone else mentioned, roots blowers are not supposed to have the TB on the charged side. It's supposed to be on the inlet side. MAF too. Check out these pics from a 12 second GTP:



and



On the GTP, the blower pretty much IS the intake manifold and the MAF is integrated into the throttle body just in front of the throttle plate. I presume this is because on the charged side, the air moves more slowly from a roots. Presumably, your idea of a recirculating would fix that to some degree. You might want to make sure you haven't blown your MAF too. Perhaps the extra noise you are hearing is coming from the exceptionally long extension you have on it.