blow off valve

hapa_poppa

Registered User
ok this is probably a stupid question to all of you sc techs but is it possible to put on a blow off valve? and if so how? if anyone did make one please message me. oh and with past experience with turbo the traditional way of having the bov before the throttle body wont work but is there any easy custom way to do it cause i really miss that sound
 
Possible

I've found myself also liking the bov sound lately. My buddy has an o3 wrx, all modded up. I've been thinkin if you put the bov on the ic return tube, run a 10% pulley, you could have the bov blow the excess pressure instead of having to pull timing out from detonation. Or maybe possible to set the bov to your desired peak boost, and have it blow right before you shift during w.o.t. runs. Just some thoughts.
 
You already have the bypass valve and you don't want to vent the boost because the MAF sensor has already accounted for that air.

There is no boost spike in our system because the supercharger is after the throttle body, so you don't need to control max pressure. The bypass allows the SC to recirculate air while not under boost which cools the SC and reduces drag.

If you really want your car to make weird noises then get a bad IAC, it will honk like a goose every time you shut it down.

Aaron
 
oh i see that kind of sucks cause i could have got a blitz bov for a 100 bucks that would be crazy on a super coupe turn a lot of heads. and what is the IAC and is it a good honking or does it sound literally like a goose. too bad a bov wouldnt work :(
 
Forget about turbo ricer crap like a noisy BOV. If you want some cool supercharger sound, start by getting a ZR intake, then you'll hear that blower whine loud and clear. And if you really want some sweet sounds, get a cog drive for the blower.
 
IAC = Idle Air Control

And it's not a good sound because it tells you that Ford is going to get another $100 of your money.

Aaeon
 
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BOV wouldn't work for our cars either, like previously mentioned MAF measures air early so if you blew off pressure it would screw up A/F ratio. Also BOV on a roots blower would cause you to lose a lot of power due to heat created at blower. It would release pressure but air would be really hot due to how it was created. Just keep boost down to perfect level in first place. Oh and as for sound, I agree with Rob, my blower whining is probably the best sound I have heard, especially if you have a muffled exhaust and that's all you hear flying by you.
 
I don't know. I'm getting bored of the 'humpback whale' whine of the supercharger. However, the M90 does sounds 10x better than any Mercedes KOMPRESSOR blower. The OTHER only thing I like about the M90, is that it has a self-contained lubrication/cooling system, unlike turbos or centrifugals. Also, if the positive displacement seizes, the intake stream is still functional to the point of drivability.

Overall, I'll always lean towards the sound of a turbo - quieter, more high pitched.
 
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Don't get me wrong, I love the sound of those hairdryers but they have become to popular. Everyone knows what they are now. But a roots blower, not many people know what they really sound like and when you whine by them and get the age old question, "what do you have in that thing?" . And as much as I love the whoosh sound of turbo, a roots sounds much better in a burnout, really turn a lot of heads with the whine.
 
Aaron Pedroza said:
Don't get me wrong, I love the sound of those hairdryers but they have become to popular. Everyone knows what they are now. But a roots blower, not many people know what they really sound like and when you whine by them and get the age old question, "what do you have in that thing?" . And as much as I love the whoosh sound of turbo, a roots sounds much better in a burnout, really turn a lot of heads with the whine.

Too popular, because it's a modern-age power adder. Who would have thought that Dodge would go back to turbos, for their new kick-*** Neon. It would be a shame to even think that an SC would get it's *** handed to a Neon. Well, thanks to modern-tech performance, it's cars like that - that put our cars to shame, stock-to-stock. If Ford had put enough thought into our cars, we could have ran a turbo setup to compete with the Grand National, or twin-turbo V6, to keep up with a 300ZX. Instead Ford wanted to keep it hush-hush, and degrade the SCs abilities because the SCs weren't allowed to go faster than a Stang 5.0s. We get motors, with an undersized displacement and ineffective power adder. If that's the case, how come the Lincoln MK8s walk all over the Stang 5.0s, and we're running on the same platform as them?:confused:
 
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Well, we were just talking about sound, not power. And as far as why Ford didn't put money into turbos at the time, they needed a lot of maintainence to be reliable. That is why very few of us, even now have "had" to change their blower. Even with technology today a turbo doesn't last 100,000 miles + like a roots blower does. It blows off any power adder for reliability. Now as far as power goes, hands down turbos make the most power if you are just looking for highest numbers but you can't judge roots blowers by our little tikes. We are very short on cfm for making real power. So what it comes down to is what you're using it for. I still think a roots blower is going to be the best thing for the strip, it will produce higher torque numbers than any turbo, but a turbo is great for street and road racing. Street because it has the lag so you can actually make tons of power without frying your tires everytime you get on it and for road racing because it is spooled up all the time and will always be making power without the loss a belt causes.
 
I don't think that would work either, without pressure the volume of air in the system would go way down and still cause metering problems.
 
Instead of using a BOV, why not use a pop off valve. It could be set to blow off any excess air after a certain psi has been reached. The benifit of this would be that you could put say a 15% pulley on the sc, and start making maximum boost 1000 RPMS sooner while also keeping your max psi at whatever you set it too. Keep in mind the SC would have to be built to take the extra spinning. I know a couple of guys with Trans Am's with the ATI Procharger and they use this set up to make 8psi at 2500 rpms instead of 3500-4000, makes for a lot more low end while maintaining the top end as well. It will also take some major computer tuning.

Have fun :)
 
but that way you still lose hp from having to spin the blower faster without gaining the hp the extra boost would add.

and if it blew off back into the intake somwhere(not necessarily the intake tube), the pressure should still be the same.

the only way i could even imagine one working (and it still probably wouldn't) is by putting it by the bypass valve, when it closes after flooring it there could be enough pressure there, but i really doubt it.
 
The beauty of a roots blower is that the amount of air pumped is a DIRECT FUNCTION OF CRANKSHAFT RPM. There is no need for any device to release excess pressure because with the proper pulley there will NEVER be excess pressure.

With a turbo the amount of air pumped is NOT a direct function of crankshaft RPM and therefore the turbo can over pressure the intake when the needs of the engine are quickly reduced - the lag in spooling up is the reaction time of the turbo system with the overpressure on throttle close being the result of said lag.

If you want to regulate max boost use the bypass valve and build a controller. You could have the system reduce max boost at lower RPMs or if wheel spin was detected.

Aaron
 
The idea of the POP off valve is to be able to spin the blower faster, in order to make max boost at the lowest posible RPM. And if you read correctly, I said if the blower was built for it, like a centrifiigual. Lastly a pop off valve does not vent air into the intake, it vents the air directly into the atmosphere. It gives you an easy way to manualy adjust the boost pressure without swapping pulleys.
 
Kinda of rediculous but i have seen many companys makes a speaker with a control unit that u hide somewhere in the engein bay and everytime you shift it will make a blow off sound. Stupid but when you show the SC'ed V6 half of the ricers dont even believe its stock when it smokes em.
Cant rememeber the exact company but im sure u could find one if u looked, i myself have always wanted a BOV sound on the SC!
 
I don't understand what the difference between a pop off valve and a blow off valve - both are used to reduce the intake pressure by venting, correct? You do not want to vent metered air to the atmosphere because it would completely screw up the mixture (extreme rich).

I don't want to turn this into a p1ssing match, but the Eaton SC is a positive displacement unit. It pushes a certain quantity of air per revolution unlike a centrifugal that creates a pressure differential based on RPM. The Eaton unit does not suffer from the low RPM boost problems that an ATI unit does. The reduction in boost pressure is from the engines ability to breath more air at those RPMs, not the failure of the blower to supply enough air. Why do you think the SC peaks torque around 2500 RPM?

Aaron
 
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