Suck through System and BOV

[RR|Suki]

Ok I was out being bored and I had a thought come into my mind.... My MAF is before the blower... that means after I release the gas and the BOV releases the air... she'll pull back timing no?? Cuz all that metered air just went to atmo...shouldn't that air go back to intake infront of the blower... or is there another way to deal with this. Cuz my BOV is on the drivers side, my intake and blower are on the passenger side... running that hose could suck since I doubt it can go over... and under would put me by the belts... any insight would be nice

[FordNut]

Ok I was out being bored and I had a thought come into my mind.... My MAF is before the blower... that means after I release the gas and the BOV releases the air... she'll pull back timing no?? Cuz all that metered air just went to atmo...shouldn't that air go back to intake infront of the blower... or is there another way to deal with this. Cuz my BOV is on the drivers side, my intake and blower are on the passenger side... running that hose could suck since I doubt it can go over... and under would put me by the belts... any insight would be nice
Most of us are setup with draw thru MAFs on our centrifugal blowers. As such, a BOV is not a good thing. It should be configured as a bypass valve instead. All the systems have different configurations and routings but the best way is to connect the bypass valve hose as close to the blower inlet as possible, which puts it as far away from the MAF as possible. It'll fit, you may even have to find some pre-molded bent hose to make it work out the best way.

[RR|Suki]

pics might help, the plumbing is there to dump the air to the blower inlet....

in pic one right behind the A/C stuff if you see a hose there connected to the inlet tube, that hose is currently plugged.... In pic two you can see where the valve is on the other side of the motor, I think I'll just get some hose and re build that connection ya?

www.msu.edu/~taylorab/mapas.jpg
www.msu.edu/~taylorab/madrive.jpg

[FordNut]

pics might help, the plumbing is there to dump the air to the blower inlet....

in pic one right behind the A/C stuff if you see a hose there connected to the inlet tube, that hose is currently plugged.... In pic two you can see where the valve is on the other side of the motor, I think I'll just get some hose and re build that connection ya?

www.msu.edu/~taylorab/mapas.jpg
www.msu.edu/~taylorab/madrive.jpg
Pretty unique setup you've got there. It looks like you could rotate the bypass valve to point down, then connect a hose from it to the bottom of the pipe on the inlet to the blower. You'll have to figure out a way to connect it at an angle pointed toward the blower so that you don't have a problem with backwash on the MAF sensor. Your PCV is setup similar to the way the FIT procharger system is configured, basically a pressure relief from the crankcase to the inlet of the blower instead of a continuous (except under boost) positive flow system. Matter of opinion as to which is better.

[SergntMac]

The original Kenny Brown design was a "blow through" MAF design consistent with centrifugal blowers at large, at the time. We have since learned more efficient methods of adding centrifugal based supercharging, but we would not have learned anything at all, without Kenny's pioneer project.

A.J...You just solved the puzzle that has haunted me since your Marauder VT engine went south. The diagnosis of "sever abuse" was inconsistent with your ownership history, and I often wondered exactly how this may have been the conclusion of VT engineers looking at the damage today. I remember discussing PCV issues with you, but we did not discuss BOV issues. I'm glad you brought this up, and thank you for posting pics too.

Your Marauder VT is a true "one of a kind". VT built just one prototype supercharged Marauder, with hopes of building more, ala Kenny Brown. This was long before Roots style of supercharging entered the picture.

Way back then, VT built engines for Kenny, and they also built a copy-cat Marauder S for the fun it. They copied his designs, his brakes, his suspension mods, his tire improvements, and a lot of other small details, but they used a Paxton NOVI 2000 blower in place of the Vortech V2-S Trim. Now (and thanks to your pics), I see that they also used a different BOV, and did not install that BOV correctly.
pics might help...

www.msu.edu/~taylorab/mapas.jpg Yes, they do. This pic shows your PCV circulation, and it's set up wrong.

The hose from the driver's side valve cover should route around back and into the upper intake, which (in this pic) is sealed off in favor of a tee connection with the passenger side PCV. We also see that the passenger side (which has a PCV valve in place when the driver's side does not) has been joined by this tee. This doesn't make any PCV sense.

I suggest you add a PCV valve to the driver's side cover, at the cover (Ford part EV-111, or, EDTZ-6A666-A) and route this hose to the upper intake. Then seal off your tee connection, and route the passenger side (which has a PCV valve in place), to where ever it leads now. I'm presuming somewhere in between the MAF, and the blower intake.
pics might help...

www.msu.edu/~taylorab/madrive.jpg Again, they do, and they solve this puzzle.

The BOV you have in place vents to atmosphere, and the placement of your MAF (as shown in pic #1) says you have a "suck through" style. Therefore, if "suck through", then "recirculate", and you're not getting that benefit if you're blowing to atmosphere. Your "bucking" is the result, and unless I miss my guess, also the cause of your engine going south.

In the pic you provide us, I can see engine oil collecting in the exhaust side of the BOV. If so, this is an oil leak that shorts the engine in upper valve lubrication, and could cause symptoms of severe engine wear, and maybe what the VT techs found in your tear-down.

Find a way of attaching a hose to this BOV exhaust (looks like 2" OD), and route that back into the intake side like the PCV, again, between the MAF and the blower inlet.

You should get a smoother drive, and with less oil consumption.

E-me, or call with your questions.

[RR|Suki]

Ok I had gotten close on the PCV valve, I actually went to buy a cobra valve today but go figure auto zone can't even get it.... so to the dealer I go...

so connect drivers side PCV to the manifold... then let passenger get evaced by the intake between the MAF and blower. Also re route the hose to re circulate my air into the intake... either way I'll call you soon then Mac, I had a feeling they had done something wrong the whole time... it's a good thing I sat outside trying to figure out what they were thinking :rolleyes:

[TooManyFords]

I'm not sure because I can't see where the passenger side pcv hose goes, but it sure looks like the same setup on my ProCharger kit. The only difference being that the BOV is not venting into the s/c intake tube after the MAF.

Regardless, there shouldn'g be oil coming out of the BOV! :eek:

Is the Novi leaking it into the pressure side? Do you see oil collecting on the intake side after the PCV vent?

John

[RR|Suki]

I'm not sure because I can't see where the passenger side pcv hose goes, but it sure looks like the same setup on my ProCharger kit. The only difference being that the BOV is not venting into the s/c intake tube after the MAF.

Regardless, there shouldn'g be oil coming out of the BOV! :eek:

Is the Novi leaking it into the pressure side? Do you see oil collecting on the intake side after the PCV vent?

John
it's probably blow by, I don't think the pcv valve is the right one, it's not really oil oil, it's actually mostly condensation I believe the blow by is the issue at hand here. we'll see when I add a pcv valve and an oil separator

The passenger side hose goes in right behind those A/C tubes in the pic, right on the neck of the intake... if you look real close you can see the brass fitting

[FordNut]

it's probably blow by, I don't think the pcv valve is the right one, it's not really oil oil, it's actually mostly condensation I believe the blow by is the issue at hand here. we'll see when I add a pcv valve and an oil separator

The passenger side hose goes in right behind those A/C tubes in the pic, right on the neck of the intake... if you look real close you can see the brass fittingIt is likely blow by, but it's blowing by the rings, then going to the inlet of the blower, then thru the blower, then coating the inside of the intercooler, then going thru the throttle body (or out the blow-by valve).

That is the "normal" setup the FIT procharger uses. I don't care for coating all the insides of my intercooler and stuff with blowby oil, so I have mine setup like Mac said. That way, at idle, or anytime the intake is under vacuum, any possible blowby is going straight into the intake. Under boost, the PCV valve closes and then any blowby goes to the inlet of the blower, but face it, we're not under boost much of the time.

The bypass valve is a real problem now. Under vacuum, it opens so with your setup it creates a huge leak of unmetered air into the engine. There is no way your engine was accurately metering air to control AFR so I am also not surprised that the engine blew.

[Warpath]

That's why I'm using breathers. I don't have to worry about oil in the intake with them. Yeah, yeah - we've had this arguement before. So, no need to repeat it. But, there are plenty of my blown Mustang bretheren who do the same.

[David Morton]

..."Now you know the rest of the story."

If VT was responsible for that BOV setup then they were responsible for their engine failure. Even the toughest internals won't last long with a non-existenet air/fuel management system, and that is what you now have. If it doesn't properly manage air/fuel, it isn't a management system, therefore you don't have one.

Frequently the function of the MAF sensor isn't well understood. It is assumed that the PCM takes in the data from the MAF sensor and then makes all fuel calculations with that data alone. Therefore if we blow off measured air to atmosphere, then the PCM will just make us too rich, not a problem. Right? WRONG!

The PCM is also looking at the O2 sensor. It knows from this data if the burn is from a rich or lean condition and will adjust the fuel accordingly, but the manufacturers found out long ago that no computer can properly manage fuel by looking at the O2 sensor alone. It's telling us what was, not what is, and we need to know what is to make an engine driveable and durable. When we blow off MAF sensor measured air, the PCM tries a richer mix but backs off as soon as it sees a rich condition at the O2 sensor. (Remember, emmissions is top priority with the PCM.) That takes a couple hundred microseconds. But as soon as you're into the throttle and the MAF measured air is correct, the burn becomes dangerously lean. The PCM will correct this too, but by that time several cylinders have been getting a very hot burn and you don't have to have been on the throttle hard at all, no detonation, just a bucking if the convertor clutch happens to be on. Now, the pistons are melting a little bit each time this occurs until some metal drops off and the meltdown starts.

Get it fixed now. Don't drive it even if it feels OK. It's tearing up a little bit every time you go from idle to even part throttle.

[Rider90]

I say...E-mail a link to this thread to VT :D

[RR|Suki]

Got the hose all set, just gotta get a PCV valve for the drivers side. I am gonna add a oil seperator inline on the passenger side, and perhaps on the drivers side just to keep an extra eye on the haps. I'll take pics of my clever hose route tomorrow, I didn't think to until I covered her up for the night... :)

[Joe Walsh]

Just my :twocents:...

I can't believe that VT would set up the S/C to blow off METERED air...:eek: ...Do you know if the original owner modified VT's set-up??

[SergntMac]

Got the hose all set, just gotta get a PCV valve for the drivers side. I am gonna add a oil seperator inline on the passenger side, and perhaps on the drivers side just to keep an extra eye on the haps. I'll take pics of my clever hose route tomorrow, I didn't think to until I covered her up for the night... :) I don't think you need to spend the money on oil seperators yet, try playing with PCV valves and hose routing, they are much cheaper to toy with.
Just my :twocents:..
I can't believe that VT would set up the S/C to blow off METERED air... Joe...That was "then". This is "now". Yes, VT could have thought this way back in 2002. But, the original owner, and his theology on supercharging a Marauder...Ummm..."Left with him." Let us do what we can, with the here and now?

[RR|Suki]

Just my :twocents:...

I can't believe that VT would set up the S/C to blow off METERED air...:eek: ...Do you know if the original owner modified VT's set-up??
Well the origional owner of the car was the owner of VT... so I should hope not... someone did it... maybe the ex owner of VT was just rich and didn't really know much, who knows. Either way I got it worked out now hopefully...

[FordNut]

Well the origional owner of the car was the owner of VT... so I should hope not... someone did it... maybe the ex owner of VT was just rich and didn't really know much, who knows. Either way I got it worked out now hopefully...
Whatcha got going with the bypass valve connection back to the blower inlet?

[RR|Suki]

Whatcha got going with the bypass valve connection back to the blower inlet? I'll post pics tomorrow, but basically what I did was got 4 feet of heater hose from a ford truck parts counter, spun the now bypass valve down wards. Connected the hose, went under my coolant res. and over and onto the intake going to the blower. On the intake side funny enough there was a fitting to accept the hose... and it was plugged. so it goes, Filter, MAF, neck, then a molded neck section with the fitting for the hose and for the PCV... took off the small section of plugged hose that was on it, put on the new hose. Actually looks quite nice, no kinks our nothin. :D

[FordNut]

I'll post pics tomorrow, but basically what I did was got 4 feet of heater hose from a ford truck parts counter, spun the now bypass valve down wards. Connected the hose, went under my coolant res. and over and onto the intake going to the blower. On the intake side funny enough there was a fitting to accept the hose... and it was plugged. so it goes, Filter, MAF, neck, then a molded neck section with the fitting for the hose and for the PCV... took off the small section of plugged hose that was on it, put on the new hose. Actually looks quite nice, no kinks our nothin. :D
Cool, surprising that the heater hose was big enough to fit on the flange of the bypass valve. Since there was already a capped off nipple at the blower inlet, it is entifely possible that the system was originally designed properly and someone put a larger bypass valve on the car, leaving the bypass hose off.

[RR|Suki]

Cool, surprising that the heater hose was big enough to fit on the flange of the bypass valve. Since there was already a capped off nipple at the blower inlet, it is entifely possible that the system was originally designed properly and someone put a larger bypass valve on the car, leaving the bypass hose off. Indeed, and the heater hose was definately a tight fit, but it ended up workin. Also that theory could be right, I know they upped the boost to 12... the ex owner said 14, but at this point I have really big doubts as to weather or not he knew what his deep pockets were buying, I think I'll have to measure the pulley. Either way, if that were the case it is entirely possible that a valve change occured, and someone got the good idea to cut the hose and plug it...

[FordNut]

Indeed, and the heater hose was definately a tight fit, but it ended up workin. Also that theory could be right, I know they upped the boost to 12... the ex owner said 14, but at this point I have really big doubts as to weather or not he knew what his deep pockets were buying, I think I'll have to measure the pulley. Either way, if that were the case it is entirely possible that a valve change occured, and someone got the good idea to cut the hose and plug it...
Could be they were going for that ricer "whoosh" from the BOV not really knowing how the system really works.

[RR|Suki]

Well I hope not, cuz even with the hose on you can hear the "woosh".

PICS... www.msu.edu/~taylorab/intakeside.jpg
www.msu.edu/~taylorab/bypassside.jpg