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Discussion Starter #1
Alright, everything I've been looking at about Bypass Valves and Blow-off Valves has been telling me that BOV's are all atmospheric. I know for certain that the ones on Eclipse's are a recirculating type. Now after reviewing both they both look the same so I'm going to assume that BPV and BOV is an interchangable term. My question is: I know that the 1G DSM ('90-'94 Mitsubishi Eclipse) BOV is a very reliable piece, as I know of one with the origional after 130,000 miles. this piece will hold boost up to about 16psi above atmospheric, and when crushed can hold more than 20psi. Now in another thread (about modded LPT's) and from specs. on the '99 2.3L LPT, I find that it doesnt boost much at all (0.5bar or ~7psi). Since with minimal upgrades (I want ~200-225 whp) would it be feasible to fit this BOV in place of the stock BPV. It may even just have a better sound to it, do you think it would hurt to put it on anyway? Its metal, cheaper than a forged and reliable. Just a thought, please post yours as it would be greatly valued.

-Mike
 

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They are not interchangable and atmospheric blow off valves are not compatible. Forge and Hyperboost are the most common BPV upgrades but these are not cheap. The problem lies with the engine management software which uses the MAF readings for air/fuel calculation. The BPV releases into the intake downstream of the MAF where the air has been accounted for. If you release the air to atmosphere the amount of air reaching the engine will be different than what the ECU expects there to be and you will have potentially bad air/fuel ratios as well as check engine lights.

Youre going to need an ECU and exhaust upgrade to reach your power target of 225whp.
 

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if you really want the PSSSSH! sound get a open air cone filter intake setup and you will hear the air return into the intake path.
 

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abdukted1456 said:
if you really want the PSSSSH! sound get a open air cone filter intake setup and you will hear the air return into the intake path.
I have that set up and the sound is awesome, both the intake sound and the DV are so cool (well I think so!) :cool:

Stock:


All that nasty black air box gone!

 

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Hi, can you do a sound file of the intake filter from inside the car, to see how it is.

But no rush, maybe some time in the future.

A particular sound to the engine can certainly add to the drive experience especially if its quiet on cruise, and just starts to growl a little under wot
 
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Chris, if the black cover has gone isnt water spray a problem?? :confused:
 

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Finn said:
Chris, if the black cover has gone isnt water spray a problem?? :confused:
Wessy custom fabricated a stainless splash guard specifically to prevent this ;)


Thedriver said:
Hi, can you do a sound file of the intake filter from inside the car, to see how it is.

But no rush, maybe some time in the future.

A particular sound to the engine can certainly add to the drive experience especially if its quiet on cruise, and just starts to growl a little under wot
I have no idea how to do that...........in the car its hardly heard unless under real load, hence having the windows open................its more of a whoosh of air being consumed under load rather than a growl, the dump valve sounds scarily like the air brakes on a bus too :cheesy:
 

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You need a filter on there for sure. Dont just run an open tube. You will suck god knows what into your engine and the MAF will not calculate properly if there is no tubing before the sensor. Go pick yourself up a cheap cone filter and a short piece of 3" SS or aluminum tubing and just put a filter on there to check it out.

Finn I have not had any problems with water intake despite my lack of a handy dandy splash guard which I would like to have! The filter sits up pretty high and it surrounded by barriers on all sides. The fender liner is going to provide the most protection as it will shield any water in the wheel well from reaching the filter. You would need to completely submerge the car up to the headlights for enough water to get in there to really cause problems.
 

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Discussion Starter #10
OK. Now I'm confused. What is the difference between a recirculating (not talking about atmospheric)) BOV and a BPV? I'm sorry as to I am used to dealing with Turbo Eclipses and the such. I know the BOV in the 1G turbo eclipses come off the intake pipe (intercooler to throttlebody), similar to the SAABs delivery pipe, and dump into the part of the intake before the turbo, I believe this is what you guys refer to as the intake pipe (snorkle looking deal). the intake setup on eclipses didnt have many upgrades so basically we bought an intake kit which came with all the pipes. It also looks like the SAABs nipple connects to a black box, the APC I take it. As the Eclipses setup is similar I was asking if it would be worth a try and whether it would be worth keeping as I intend to mod later using an Aero turbo and possibly a BSR Stage 2 or Aero ECU (due to low demand on Aero ECUs in the US I might be able to source one cheaper than the PCM upgrade).
 

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A recirculating dump valve is the same as a bypass valve. If you are releasing freely into the engine bay its a blow off valve. If you are releasing back into the intake stream it's a bypass valve. You should probably just get any and all Mitsubishi information out of your mind and start fresh. If the valve has two stems on it, it's probably what you need. If it looks like a bulb hanging off your intake without a second connection, it's not going to work.
 

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Discussion Starter #12
This is a pic of a lightly upgraded Eclipse.



The purple thing is the BOV. As you see it is connected to the pipe blow it (akin to the delivery pipe), and to the pipe toward the front of the car behind the electrical box (MAF) but before the turbo. I feel that this could work and i cant see how it wouldn't. Please explain.
 

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I see. It'd be erasing more than mitsu's, theres turbo'd honda's, nissan (i was designing a roots supercharger to go on there from a S/C mr2)......yeah, I'm sufficiently tweaked.

I was just considering this as a possible alternative since I can get them cheap. maybe i'll just get one to play with.
 

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I think you will get a Check Engine Light quite quickly :cry:
 

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If the air is released into a stem that can be directed to where you need it to go, it should work. If the air is released through holes into the engine bay, it won't work. You also need to make sure the valve will fit in the tight space where the small stock Bosch valve fits.
 

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XAAMOTTOMAAX said:
You need a filter on there for sure. Dont just run an open tube. You will suck god knows what into your engine and the MAF will not calculate properly if there is no tubing before the sensor. Go pick yourself up a cheap cone filter and a short piece of 3" SS or aluminum tubing and just put a filter on there to check it out.
Ok, so I need to leave the tubing before the MAF. Fine, I'll just put some mesh for a an old screen door on there to keep big bits of stuff out and see what it sounds like. This is just to run it around the block and hear the difference, it's only temporary. If I like it I'll get a real filter.
 

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XAAMOTTOMAAX said:
You might as well get a filter now because you are going to think it sounds great. :cheesy:
Oh yes :cheesy: :cheesy: :cheesy:
 

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I have no idea how to do that...........in the car its hardly heard unless under real load, hence having the windows open................its more of a whoosh of air being consumed under load rather than a growl, the dump valve sounds scarily like the air brakes on a bus too :cheesy:[/QUOTE]

Just get one of those cheap tape cassette players and plug in a mic, then make the recording in car, then plug your mic into computer, and replay recording into computer and record using windows media player

You will now have a wav file or other sound file for posting :lol:
 

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OMG a fellow DSM on a saab board :)
i'm looking at dumping my svt contour for a 9-5 aero sometime late summer.

don't you go dumping that dsm knowledge just yet :nono;

as for the BOV vs BPV. They serve the same function. To release air(boost) that is being pushed from the turbo to the tb after the butterfly has been closed.

as long as you keep the intake plumbing the same you will be fine with any BOV.
The software running a LPT will FREAK when vented.
the computer is EVERYTHING to these cars.

its worse than the controllers on the evo, however
saabs are SOOOO enviro friendly it's scary.



sadly enough, the saab motors are not like the 4g63, you have to be careful :(
 
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