were is he BOV located on a 1997 gst spyder
#24
11-30-2005, 12:34 PM
RE: were is he BOV located on a 1997 gst spyder
ORIGINAL: Patrick
and as for venting to the atmosphere, i have seen an Awful lot of cars running an atmosphere-vented bov that ran much better than your average bucket...
and as for venting to the atmosphere, i have seen an Awful lot of cars running an atmosphere-vented bov that ran much better than your average bucket...
#26
11-30-2005, 02:05 PM
RE: were is he BOV located on a 1997 gst spyder
i dont doubt you by any stretch, but i have a question. my turbo car is an old dodge daytona, and very few of them came with BOVs, and they allowed the boost pressure to stack up, which greatly shortened the life of the turbo. the first mod that many guys do, is add a bov, which i will be doing once i get a new head gasket and such. so my question to you, how does it affect a system like mine, which comes with literally no BOV or bypass valve, when i put an atmospheric bov on the system?
#28
11-30-2005, 02:14 PM
RE: were is he BOV located on a 1997 gst spyder
What is a crushed BOV?
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Owners of highly boosted cars have discovered that the stock 1G BOV tends to begin to open too early. This causes a pressure leak in the intake system that limits boost. The valve tends to leak somewhat at lower boost levels, then opens fully when it's supposed to. This low-level leakage is the problem. The 1G BOV will usually hold pressures to about 22 psi, so this problem usually only appears on cars with upgraded turbochargers.
[2G owners have this problem, times two - the stock 2G BOV can just hold stock boost levels, and tends to start leaking at around 15 psi. 2Gers don't crush their BOV because it's plastic and won't crush. Instead, 2Gers often replace their unit with a stock 1G BOV to eliminate the leakage problem. This works until they too reach the limits of the 1G BOV.]
One DIY solution proposed to fix this problem is to crush the BOV. This means exactly what it says - stick the valve into a vise or clamp and squish it so it doesn't open as early. This is really a cheap & dirty method of increasing the spring force holding the BOV shut, and saves the operator from having to install an expensive aftermarket BOV. This techique can, however, restrict the amount of air that can pass through the BOV when it is wide open, making it a less efficient BOV, and therefore not as good as an aftermarket unit. All of this theory was explained by Todd Hayashi in his August 31/99 post on the subject. A follow-up summary post by Robert Mangus can be found here.
Although the technique is simple, individuals should use caution in applying it since various BOVs and crushing techniques are different. The essential technique is to crush the BOV so that it begins to open when 18-20 inHg of vacuum is applied to the reference port. Pristine BOVs will begin to open much earlier than this. Crushing should be done a little at a time until the BOV responds properly. Over-crushing a BOV may result in poor performance.
One opponent to this technique is Jim McKenna; he explains here how moving the BOV pressure reference solves the leakage problem. (Jim explains his original concept here.) Aaron Becker disagreed with the idea, while Warren Tsai supported it. As with most information available about this modification, this debate remains incomplete. Regardless, owners of stock turbochargers need not concern themselves, as the stock 1G BOV works just fine with stock turbos.
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Search for this topic now!
Owners of highly boosted cars have discovered that the stock 1G BOV tends to begin to open too early. This causes a pressure leak in the intake system that limits boost. The valve tends to leak somewhat at lower boost levels, then opens fully when it's supposed to. This low-level leakage is the problem. The 1G BOV will usually hold pressures to about 22 psi, so this problem usually only appears on cars with upgraded turbochargers.
[2G owners have this problem, times two - the stock 2G BOV can just hold stock boost levels, and tends to start leaking at around 15 psi. 2Gers don't crush their BOV because it's plastic and won't crush. Instead, 2Gers often replace their unit with a stock 1G BOV to eliminate the leakage problem. This works until they too reach the limits of the 1G BOV.]
One DIY solution proposed to fix this problem is to crush the BOV. This means exactly what it says - stick the valve into a vise or clamp and squish it so it doesn't open as early. This is really a cheap & dirty method of increasing the spring force holding the BOV shut, and saves the operator from having to install an expensive aftermarket BOV. This techique can, however, restrict the amount of air that can pass through the BOV when it is wide open, making it a less efficient BOV, and therefore not as good as an aftermarket unit. All of this theory was explained by Todd Hayashi in his August 31/99 post on the subject. A follow-up summary post by Robert Mangus can be found here.
Although the technique is simple, individuals should use caution in applying it since various BOVs and crushing techniques are different. The essential technique is to crush the BOV so that it begins to open when 18-20 inHg of vacuum is applied to the reference port. Pristine BOVs will begin to open much earlier than this. Crushing should be done a little at a time until the BOV responds properly. Over-crushing a BOV may result in poor performance.
One opponent to this technique is Jim McKenna; he explains here how moving the BOV pressure reference solves the leakage problem. (Jim explains his original concept here.) Aaron Becker disagreed with the idea, while Warren Tsai supported it. As with most information available about this modification, this debate remains incomplete. Regardless, owners of stock turbochargers need not concern themselves, as the stock 1G BOV works just fine with stock turbos.
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#30
11-30-2005, 02:24 PM
RE: were is he BOV located on a 1997 gst spyder
well it may make a difference but it all depends on how your car calculated incoming air. the MAS on the mitsubishis reads prior to the turbo on the intake side it calculates as it passes threw. the BOV is on the pipperIC pipe before the Throttle body when at WOT your boosting the car, and the when you back off the BOV releases the pressure (so you dont get compressor surge which kills the turbos life) when that air is released it has already been counted by the MAS so if you vent it off to the atmosphere you lose it and because it has been clculated for already the ECU assumes it is still there and adds the nessesary fuel to keep AFR as it should, when that air doesnt reach the chamber the car is overwelmed i guess with the fuel and runs super rich between shifts which boggs it at idle and nearly stalls the car.
Also at 1/4 to 3/4 throttle you can barley drive the car because if it builds a small amount of boost the BOV is partcailly open and the car will buk hard untill it closes. and the lose of the air release for the BOV between shifts will increase the turbos lag time in the next gear.
Ok now if the daytona uses MAP to calculate air then a VTA will have no bearing on the way the car runs because it reads as it enters the motor. but knowing that dodge and mitus are alot alike id assume you are like all mitsus and need a re circ. to run properly. when you run no BOV the car ECU still gets the air that has been calulated it doesnt lose any so it wont run rich like if it would lose the air. with a tune the car can run semi normal with VTA
Also at 1/4 to 3/4 throttle you can barley drive the car because if it builds a small amount of boost the BOV is partcailly open and the car will buk hard untill it closes. and the lose of the air release for the BOV between shifts will increase the turbos lag time in the next gear.
Ok now if the daytona uses MAP to calculate air then a VTA will have no bearing on the way the car runs because it reads as it enters the motor. but knowing that dodge and mitus are alot alike id assume you are like all mitsus and need a re circ. to run properly. when you run no BOV the car ECU still gets the air that has been calulated it doesnt lose any so it wont run rich like if it would lose the air. with a tune the car can run semi normal with VTA