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Discussion Starter #1
There are many bungs availaable to mount an aftermarket valve on a stock hot pipe, but are there any bungs that do vice versa?

I am attempting to mount a stock BPV on a 2.5" SS pipe. Its obvious that I could weld it on, but since stock BPVs are $$$, I'd rather not ruin it as I still dont' know if my test is going to work well or not.

Has anybody CUT the bung portion off a stock hot pipe and "grafted" it onto another pipe? That is all I can think of, but the stock hot pipe is AL, and my pipes are SS, making it rather hard to atached the two :(
 

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I hate that the stock BPV is secured by one bolt and an o-ring. That seems so lop-sided to me. When you've got a 20G pushing 350-400whp, how does that thing not leak?
 

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Discussion Starter #4 (Edited)
After some research I've decided a T-hose is my best bet, and it is completely reversible.



Now the only problem is finding one in the right size...everybody makes 51 and 55 mm (~2") but I have 2.5" piping (~63mm) and 3" (76mm) on my other car :(. Turbohoses has it listed on their website so perhaps I'll give them a call....

Anybody else know where i can get Thoses in larger diameters?
 

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Discussion Starter #5
boostd4 said:
I hate that the stock BPV is secured by one bolt and an o-ring. That seems so lop-sided to me. When you've got a 20G pushing 350-400whp, how does that thing not leak?
I always have the same thought when taking it on and off (just had that thought 20 min ago out in the garage LOL) but really its a pipe inside a hole, and it is sealed by an Oring. I doubt you get much leakage. What I would be worried about is running 25+ psi and busting the damned thing off from the leverage!!
 

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Justin,

LoL I havent even sold one of those yet. I have 2"ID and 2.5"ID. The bung is for 1" adapters you can probably buy from ATP. I dont even know how much the hose costs. I also have a steel version of the stock BOV flange we use for our stage 7 piping. I think it costs in the neighborhood of $45 because it's a custom machined peice.
 

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Justin311 said:
I always have the same thought when taking it on and off (just had that thought 20 min ago out in the garage LOL) but really its a pipe inside a hole, and it is sealed by an Oring. I doubt you get much leakage. What I would be worried about is running 25+ psi and busting the damned thing off from the leverage!!

the design of the oem bpv...the higher you boost, the tighter it will seal
 

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Discussion Starter #8
Pred said:
Justin,

LoL I havent even sold one of those yet. I have 2"ID and 2.5"ID. The bung is for 1" adapters you can probably buy from ATP. I dont even know how much the hose costs. I also have a steel version of the stock BOV flange we use for our stage 7 piping. I think it costs in the neighborhood of $45 because it's a custom machined peice.
Ah, glad you joined the thread. I had a realization LOL.

Marks old car has your "stage 7" IC piping, correct? Because that is the new 3" piping that is going on my car...does it have the stock BPV fitting already welded on it? From this pic I think it might:

http://www.turbohoses.com/Turbohoseslargeintakefront.jpg

Good to know you have the fitting, however, because I may be running 2 BOVs in teh future so I may have to pick one up from you. $45 sounds reasonable actually, thanks for the info ;)
 

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We're not talking about the BPV valve/diaphram (where the above is true). We're talking about the o-ring below it, and the one bolt that holds the whole thing on.

The valve won't leak on boost but the seal that sits under the valve has me scratching my head. It'd just be much more reassuring if there were another bolt on the other side. Really.. how much could that have saved toyota... it's not like they even made that many MR2's (compared to Camry's, etc...)..
 

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Discussion Starter #10
Pred said:
I have 2"ID and 2.5"ID. The bung is for 1" adapters you can probably buy from ATP.
Can you email me a price on the 2.5" ID one when you get a second? That is what I am after should I keep this IC piping. Thx :)

Justins311 at hotmail.com
 

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You can request any size pipe, and the flange can be welded onto anything as long as it's steel. I'll email you the price tomorrow. That BOV hose was origionally for DSMs. You can use any 1" adapter for the HKS BOV/Greddy that ATP sells as well.
 

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Justin311 said:
I always have the same thought when taking it on and off (just had that thought 20 min ago out in the garage LOL) but really its a pipe inside a hole, and it is sealed by an Oring. I doubt you get much leakage. What I would be worried about is running 25+ psi and busting the damned thing off from the leverage!!
25 psi, while a lot in terms of boost, really isnt that much relative to pressures in general. Your tires probably have 1.5 to 2 times that in them, for example. A standard shop air compressor is making 120ish psi.

If you look at the size of the opening, its probably about 1 square inch of surface area. So 25lbs of force. Thats definetly not going to shear that bolt or bend the flange on the BOV.
 

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Discussion Starter #13
WyrmMaster said:
25 psi, while a lot in terms of boost, really isnt that much relative to pressures in general. Your tires probably have 1.5 to 2 times that in them, for example. A standard shop air compressor is making 120ish psi.

If you look at the size of the opening, its probably about 1 square inch of surface area. So 25lbs of force. Thats definetly not going to shear that bolt or bend the flange on the BOV.
LOL...tire and air compressor pressure really have no comparison to what we're talking about, there is no lever arm. If you have had an IC hose blow off at 25 psi you will know there is a decent amount of force behind it.

To get technical I beleive the force acting on the valve would be the absolute pressure, which is 25+14.7= 40 lbs/ square inch absolute.
The design of the bPV attachment means you are hanging 40 lbs off that bolt over a lever arm of ~3". T = Fd so 40*3/12 = about 10 ftlbs.

Its definitely not enough to shear that bolt, but that is only an 8mmx1.25 bolt that is threaded into aluminum. To analyze it much further we would need to calculate all sorts of dirty stuff like the force on the thread ramp (can't remember the technical term) blah blah blah. A neat experiment if anybody is super bored would be to secure the IC pipe/BPV assembly in the air upside down and hang a 10 lb weight off of the BPV. Then run some smoke thru the IC pipe and see if any came out the seam? ;)
 

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mark's car had a Stage 7 that was upgraded to 3" pipe. the OEM BOV flange (our machined part) is just the flange. His HKS bov is using the MR2 adapter kit. It's all welded together with the bung. These pieces are hand made. The price is the cost of materials + the labor to do it basically.
 

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Justin311 said:
To get technical I beleive the force acting on the valve would be the absolute pressure, which is 25+14.7= 40 lbs/ square inch absolute.
The design of the bPV attachment means you are hanging 40 lbs off that bolt over a lever arm of ~3". T = Fd so 40*3/12 = about 10 ftlbs.
except that atmospheric pressure is also acting on the outside of the valve, effectivly holding in on. So the only part that matters is the additional pressure of the charge air.

I know that the other pressure examples arnt really too applicable, I was just making examples to show how the 25psi in your intake isnt really much compared with the pressures that common everyday things deal with.

I do agree with your analysis of the lever arm concept, and yes, it would probably be IDEAL to have two bolts, but, assuming the o-ring is in good shape, I don't see it causing a problem. I could go nuts and analyse the various stresses incured in the flange, but honestly, I dont think there is a danger of leaking via this method. I think the most likely cause of a leak at this point would be a defective o-ring, not some bending of the flange due to the pressure.
 

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Discussion Starter #18
Probably some good points you bring up.

The reason I was discussing ways the valve could leak is because people *have* had leaky BPVs at high pressure before, although its not widely talked about on the board becuase everybody jumps on them and says its not possible. Obviously the design of the valve is such that as boost increases so does clamping force, so if one were to leak, there would either have to be something seriously wrong with the valve (they didn't find it upon inspection) or be a leak at the mounting point.
 
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