[snugz00]

i have a 1991 ford thunderbird supercoupe with a roots style supercharger my friend said i could put a BOV on it i was wondering if thats true or is he full of #h$t.

[MSTNGRCR13]

I don't believe that you can install a BOV on a roots style S/C, but I could be mistaken. I believe that you can only install a BOV on a centrifugal style that mounts forward of the engine similar to the Paxton, Vortech, or Procharger, but not a roots style that mounts on top of the engine. If I am wrong, which has been known to happen occasionally, there should be other people on here that can help with that. I hope that this helps.

[turp]

Originally Posted by MSTNGRCR13 I don't believe that you can install a BOV on a roots style S/C, but I could be mistaken. I believe that you can only install a BOV on a centrifugal style that mounts forward of the engine similar to the Paxton, Vortech, or Procharger, but not a roots style that mounts on top of the engine. If I am wrong, which has been known to happen occasionally, there should be other people on here that can help with that. I hope that this helps.

Ding ding ding #1 answer. John show him what he's won! BOV's are for turbo's and centrifical superchargers and even then I don't know anyone that runs a BOV on thier SC. The supercoupe makes 12 PSI of boost stock and there is no need for a BOV even with a 15% underdrive pulley on the crank and a 10% UD pulley on the blower you will still only be making 16 - 17 pounds of boost in which the forged internals can handle nicely. Watch those head gaskets though. I would def. order a 5 layer stainless steel set from Morana racing before I upped the boost in that motor as the H/G's in the supercoupe were "Compressionally challenged" to say the least!

[ChrisJ]

Originally Posted by turp Originally Posted by MSTNGRCR13 I don't believe that you can install a BOV on a roots style S/C, but I could be mistaken. I believe that you can only install a BOV on a centrifugal style that mounts forward of the engine similar to the Paxton, Vortech, or Procharger, but not a roots style that mounts on top of the engine. If I am wrong, which has been known to happen occasionally, there should be other people on here that can help with that. I hope that this helps. Ding ding ding #1 answer. John show him what he's won! BOV's are for turbo's and centrifical superchargers and even then I don't know anyone that runs a BOV on thier SC. The supercoupe makes 12 PSI of boost stock and there is no need for a BOV even with a 15% underdrive pulley on the crank and a 10% UD pulley on the blower you will still only be making 16 - 17 pounds of boost in which the forged internals can handle nicely. Watch those head gaskets though. I would def. order a 5 layer stainless steel set from Morana racing before I upped the boost in that motor as the H/G's in the supercoupe were "Compressionally challenged" to say the least!

Another words he blew a head gasket...

[turp]

Originally Posted by ChrisJ Originally Posted by turp Originally Posted by MSTNGRCR13 I don't believe that you can install a BOV on a roots style S/C, but I could be mistaken. I believe that you can only install a BOV on a centrifugal style that mounts forward of the engine similar to the Paxton, Vortech, or Procharger, but not a roots style that mounts on top of the engine. If I am wrong, which has been known to happen occasionally, there should be other people on here that can help with that. I hope that this helps. Ding ding ding #1 answer. John show him what he's won! BOV's are for turbo's and centrifical superchargers and even then I don't know anyone that runs a BOV on thier SC. The supercoupe makes 12 PSI of boost stock and there is no need for a BOV even with a 15% underdrive pulley on the crank and a 10% UD pulley on the blower you will still only be making 16 - 17 pounds of boost in which the forged internals can handle nicely. Watch those head gaskets though. I would def. order a 5 layer stainless steel set from Morana racing before I upped the boost in that motor as the H/G's in the supercoupe were "Compressionally challenged" to say the least! Another words he blew a head gasket...

Nope. I have never had a "running" supercoupe. I had one I got from an auction that had blown H/G's and researched it heavily and that is what I found out more or less.

[ChrisJ]

Originally Posted by turp Originally Posted by ChrisJ Originally Posted by turp Originally Posted by MSTNGRCR13 I don't believe that you can install a BOV on a roots style S/C, but I could be mistaken. I believe that you can only install a BOV on a centrifugal style that mounts forward of the engine similar to the Paxton, Vortech, or Procharger, but not a roots style that mounts on top of the engine. If I am wrong, which has been known to happen occasionally, there should be other people on here that can help with that. I hope that this helps. Ding ding ding #1 answer. John show him what he's won! BOV's are for turbo's and centrifical superchargers and even then I don't know anyone that runs a BOV on thier SC. The supercoupe makes 12 PSI of boost stock and there is no need for a BOV even with a 15% underdrive pulley on the crank and a 10% UD pulley on the blower you will still only be making 16 - 17 pounds of boost in which the forged internals can handle nicely. Watch those head gaskets though. I would def. order a 5 layer stainless steel set from Morana racing before I upped the boost in that motor as the H/G's in the supercoupe were "Compressionally challenged" to say the least! Another words he blew a head gasket... Nope. I have never had a "running" supercoupe. I had one I got from an auction that had blown H/G's and researched it heavily and that is what I found out more or less.

In other words he looked and searched for the best way to fix a headgasket someone had blown prior to his ownership of a Supercoupe...And thus found out the information to be true...

Lesson here...Dont blow headgaskets...They seriously dont like it...

[turp]

Originally Posted by ChrisJ Originally Posted by turp Originally Posted by ChrisJ Originally Posted by turp Originally Posted by MSTNGRCR13 I don't believe that you can install a BOV on a roots style S/C, but I could be mistaken. I believe that you can only install a BOV on a centrifugal style that mounts forward of the engine similar to the Paxton, Vortech, or Procharger, but not a roots style that mounts on top of the engine. If I am wrong, which has been known to happen occasionally, there should be other people on here that can help with that. I hope that this helps. Ding ding ding #1 answer. John show him what he's won! BOV's are for turbo's and centrifical superchargers and even then I don't know anyone that runs a BOV on thier SC. The supercoupe makes 12 PSI of boost stock and there is no need for a BOV even with a 15% underdrive pulley on the crank and a 10% UD pulley on the blower you will still only be making 16 - 17 pounds of boost in which the forged internals can handle nicely. Watch those head gaskets though. I would def. order a 5 layer stainless steel set from Morana racing before I upped the boost in that motor as the H/G's in the supercoupe were "Compressionally challenged" to say the least! Another words he blew a head gasket... Nope. I have never had a "running" supercoupe. I had one I got from an auction that had blown H/G's and researched it heavily and that is what I found out more or less. In other words he looked and searched for the best way to fix a headgasket someone had blown prior to his ownership of a Supercoupe...And thus found out the information to be true... Lesson here...Dont blow headgaskets...They seriously dont like it...

Pretty Much yeah! Plus the top end on that bitch is hell to get off!

[ChrisJ]

Originally Posted by turp Originally Posted by ChrisJ Originally Posted by turp Originally Posted by ChrisJ Originally Posted by turp Originally Posted by MSTNGRCR13 I don't believe that you can install a BOV on a roots style S/C, but I could be mistaken. I believe that you can only install a BOV on a centrifugal style that mounts forward of the engine similar to the Paxton, Vortech, or Procharger, but not a roots style that mounts on top of the engine. If I am wrong, which has been known to happen occasionally, there should be other people on here that can help with that. I hope that this helps. Ding ding ding #1 answer. John show him what he's won! BOV's are for turbo's and centrifical superchargers and even then I don't know anyone that runs a BOV on thier SC. The supercoupe makes 12 PSI of boost stock and there is no need for a BOV even with a 15% underdrive pulley on the crank and a 10% UD pulley on the blower you will still only be making 16 - 17 pounds of boost in which the forged internals can handle nicely. Watch those head gaskets though. I would def. order a 5 layer stainless steel set from Morana racing before I upped the boost in that motor as the H/G's in the supercoupe were "Compressionally challenged" to say the least! Another words he blew a head gasket... Nope. I have never had a "running" supercoupe. I had one I got from an auction that had blown H/G's and researched it heavily and that is what I found out more or less. In other words he looked and searched for the best way to fix a headgasket someone had blown prior to his ownership of a Supercoupe...And thus found out the information to be true... Lesson here...Dont blow headgaskets...They seriously dont like it... Pretty Much yeah! Plus the top end on that bitch is hell to get off!

I blew a headgasket on a turbo coupe once...That was funny...I bought it for $500 at action...Was going to strip it...Motor had 200K or so on it...SO I said f*ck it...Lets see how much it can hold...They can hold quite a bit of boost...But nitrous kills them fast...

[turp]

So funny I got this one at auction for 300

[Drgnracin72]

even the cntrifugal s/c dont use a bov. its a bipass valve. it ets the compressed air out and outs it back into the intake stream

[ChrisJ]

Originally Posted by drgnracin72 even the cntrifugal s/c dont use a bov. its a bipass valve. it ets the compressed air out and outs it back into the intake stream

Isnt that only with the Vortech Race Bypass Valve?

[Drgnracin72]

thats what centifugal use. if you ise a bov, you getting rid of metered air. procharger, vortech and a few toehr companies make em. its essentially a bov but it vents into the intake stream and not out into the open

[ChrisJ]

Originally Posted by drgnracin72 thats what centifugal use. if you ise a bov, you getting rid of metered air. procharger, vortech and a few toehr companies make em. its essentially a bov but it vents into the intake stream and not out into the open

Yeah I knew that...But I heard of people doing away with the bypass valve for some reason that I cant remember...

[ChrisJ]

Here is what I was talking about

[Drgnracin72]

um where tlaking about the same thing. it doesnt vent into the atmospere. i guess you could vent it into the atmosphere but then your losing metered air!

edit: that video that they posted in that thread is exactly what my stock procharger bypass valve sounds like. i think i am going ot run a procharger race bypass when i get the blower back on, but ill def have to do somehting. that little tiny stock one wont be able to handle the pressure

[ChrisJ]

Originally Posted by drgnracin72 um where tlaking about the same thing. it doesnt vent into the atmospere. i guess you could vent it into the atmosphere but then your losing metered air! edit: that video that they posted in that thread is exactly what my stock procharger bypass valve sounds like. i think i am going ot run a procharger race bypass when i get the blower back on, but ill def have to do somehting. that little tiny stock one wont be able to handle the pressure

Oh I misunderstood ya...

I thought you said they dont make one that vents to the autmosphere...Its all good...I re-read your post and see that I skipped words...lol

[mustang_montana]

some of the newer twinscrew/roots have internal bypasses, but i really dont understand why a screw/roots would need one considering the tb is before the compressor.

[5literJeff]

I also have a 91 ford thunderbird SC that is modified (majority of the work done by me) so if you want to know anything fire away.

Mine dynoed at 278 rear wheel horsepower through the AOD awhile back and that was without the custom intercooler I use for drag racing that packs dry ice in. Mods include aftermarket throttle body, mass air, exhaust, custom inlet and outlet tubes for the intercooler tubing as well as polished tubes on the inside, blower pulley and more.

The factory boost gage is kind of misleading, in that it is registering the air temperature from the heated compressed air, and the backpressure from the restrictive inlet ducting and blower top, as 'boost' in the manifold.
The adiabatic efficiency of the stock roots type blower is horrible. In other words the act of compressing the air by that blower heats up the air way more then a centrifugal would, and that additional heat creates 'boost' that isnt really there. The actual amount of boost on a stock intercooler/manifold SC that the heads actually see is more around 8 psi. Once you bolt on a more free flowing intercooler (and tubes) and supercharger inlet top you can get your boost up at the heads to around 12 actual psi which helps tremendously.

Oh and like others have said your friend is wrong you dont want a blow off valve on the SC. The SC already has a built in valve that works fine and does the same thing basically as what a blow off valve would do. Sure the BOV sounds cool but its not needed on a SC.

Also you might want to see http://www.sccoa.com/ for all your super coupe needs. I am no longer a member but I was once and they have all the info you could ever want for your car.

[loudenough]

well you can install one but that will kill what a roots blower is ment for


low to hi-end boost all the time


See a BOV is ment to stop or slow boost on de-throtle (mostly turbo) and to keep boost up so it is there when you hit the throtle again(your turbo is spun up to speed and just waiting for the driver to open the throtle to close the BOV and get there boost)

see most superchargers are belt driven and will go down in boost with the RPM`s of the engine

Also please note it takes way more time for a turbo to gain boost then any supercharger

[dano]

or =red][/color]http://morana 3.8 engine for sale. b...ao@aol.com</a>