Something interesting venting BOV to atmosphere.
Evolved Member
Joined: Jan 2006
Posts: 953
Likes: 2
From: Oxfordshire
You can run speed density on the stock ECU. Bez has done it and has offered to help patch other ECUs, if wanted. Maybe send him a PM on AktiveMatrix or read through the whole thread about it.
Also, burgers option above would work, too. I had a GM MAF on my Eclipse years ago in blow-through....worked great. Although, even with that, you're still going to want a BOV that will stay closed at idle and part throttle.
Whatever you do, if you sell you IX DV, let me know. I may be interested, since I need to get rid of my plastic VIII DV.
Eric
Also, burgers option above would work, too. I had a GM MAF on my Eclipse years ago in blow-through....worked great. Although, even with that, you're still going to want a BOV that will stay closed at idle and part throttle.
Whatever you do, if you sell you IX DV, let me know. I may be interested, since I need to get rid of my plastic VIII DV.
Eric
Interesting ideas.
the mitsu MAF is gigantic. Welding one in for blow through would be a little cumbersome.
I've done that on my IS300.
Eh...
I'll just recirc it. i don't want to deal with it. This is my daily car.
the mitsu MAF is gigantic. Welding one in for blow through would be a little cumbersome.
I've done that on my IS300.
Eh...
I'll just recirc it. i don't want to deal with it. This is my daily car.
Stock BOVs are push type .. pressure on the UICP pushes the valves and if the pressure exceeds the spring rating, the valves open and you get leakage
What I would do if I want to prevent leaks at part throttle .. flip the stock BOV around ..
make it into a pull type BOV .. trust me .. it holds more than 26psi (I tested till then and stopped 
) Make it similar to a HKS pull type
Since the springrate for the DV is fixed .. you'll get flutter at light throttle liftoffs
Oh do be careful .. if you're using a EBC .. there'll be no more boost taper
Last edited by gunzo; Aug 2, 2007 at 06:58 AM.
Here's something for you to think ..
Most aftermarket BOVs (if not all) are pull type valves .. ie it uses vacuum from the manifold when you close throttle to pull the valve open .. that's why after market BOVs don't leak .. because the pressure pushes the valve seats tighter when the UICP is pressurised ..
Stock BOVs are push types .. pressure on the UICP pushes the valves and if the pressure exceeds the spring rating, the valves open and you get leakage
What I would do if I want to prevent leaks at part throttle .. flip the stock BOV around .. make it into a pull type BOV .. trust me .. it holds more than 26psi (I tested till then and stopped )
Since the springrate for the DV is fixed .. you'll get flutter at light throttle liftoffs
Oh do be careful .. if you're using a EBC .. there'll be no more boost taper
Most aftermarket BOVs (if not all) are pull type valves .. ie it uses vacuum from the manifold when you close throttle to pull the valve open .. that's why after market BOVs don't leak .. because the pressure pushes the valve seats tighter when the UICP is pressurised ..
Stock BOVs are push types .. pressure on the UICP pushes the valves and if the pressure exceeds the spring rating, the valves open and you get leakage
What I would do if I want to prevent leaks at part throttle .. flip the stock BOV around ..
make it into a pull type BOV .. trust me .. it holds more than 26psi (I tested till then and stopped ) Since the springrate for the DV is fixed .. you'll get flutter at light throttle liftoffs
Oh do be careful .. if you're using a EBC .. there'll be no more boost taper
I don't get very much taper right now anyway.
So are you running with the stock diverter flipped around?
MAFT Pro for converting to speed density (for the translation) if Bez for whatever reason didnt want to share and then continue to use the stock ECU to tune. Use just MAFT for a GM hotwire or rescale the MAF as Jack did and use the stock ECU to control a blowthrough and tune.
Going to speed density doesnt preclude the use of ECUflash, just alters how you use it. One reason I can think of for using MAFT Pro is that as I currently understand it (though I am sure you could rescale the 3bar MAP output since there is a table) you are limited to the JDM 3 bar with the stock ECU. Like I said I am sure this can be tuned around by using provided tables, but MAFT Pro can use larger than 3 Bar map sensors and send the data to the stock ECU. The next phase of my build will incorporate speed density and the stock ECU in some form.
Going to speed density doesnt preclude the use of ECUflash, just alters how you use it. One reason I can think of for using MAFT Pro is that as I currently understand it (though I am sure you could rescale the 3bar MAP output since there is a table) you are limited to the JDM 3 bar with the stock ECU. Like I said I am sure this can be tuned around by using provided tables, but MAFT Pro can use larger than 3 Bar map sensors and send the data to the stock ECU. The next phase of my build will incorporate speed density and the stock ECU in some form.
MAFT Pro for converting to speed density (for the translation) if Bez for whatever reason didnt want to share and then continue to use the stock ECU to tune. Use just MAFT for a GM hotwire or rescale the MAF as Jack did and use the stock ECU to control a blowthrough and tune.
Going to speed density doesnt preclude the use of ECUflash, just alters how you use it. One reason I can think of for using MAFT Pro is that as I currently understand it (though I am sure you could rescale the 3bar MAP output since there is a table) you are limited to the JDM 3 bar with the stock ECU. Like I said I am sure this can be tuned around by using provided tables, but MAFT Pro can use larger than 3 Bar map sensors and send the data to the stock ECU. The next phase of my build will incorporate speed density and the stock ECU in some form.
Going to speed density doesnt preclude the use of ECUflash, just alters how you use it. One reason I can think of for using MAFT Pro is that as I currently understand it (though I am sure you could rescale the 3bar MAP output since there is a table) you are limited to the JDM 3 bar with the stock ECU. Like I said I am sure this can be tuned around by using provided tables, but MAFT Pro can use larger than 3 Bar map sensors and send the data to the stock ECU. The next phase of my build will incorporate speed density and the stock ECU in some form.
As I recall (its been awhile) it comes with an IAT sensor since you cant use the one built into the MAF. Non US cars come with an intake manifold mounted IAT that we only have an undrilled bung for. I am gonna go read the MAFTpro thing again and see if I can decipher some details.
You could also hum a few bars and fake it...I have tuned plenty of Hondas without using the IAT.
edit:
Straight from their website-
Air Temp:
Air temp correction, setting is added to the regular system tune value. Note this adjustment is in addition to the Speed Density algorithm's temperature compensation. Additional adjustment can be required to adjust for atomization characteristics of injectors, or heat-soak conditions.
You could also hum a few bars and fake it...I have tuned plenty of Hondas without using the IAT.
edit:
Straight from their website-
Air Temp:
Air temp correction, setting is added to the regular system tune value. Note this adjustment is in addition to the Speed Density algorithm's temperature compensation. Additional adjustment can be required to adjust for atomization characteristics of injectors, or heat-soak conditions.
Here's something for you to think ..
Most aftermarket BOVs (if not all) are pull type valves .. ie it uses vacuum from the manifold when you close throttle to pull the valve open .. that's why after market BOVs don't leak .. because the pressure pushes the valve seats tighter when the UICP is pressurised ..
Stock BOVs are push types .. pressure on the UICP pushes the valves and if the pressure exceeds the spring rating, the valves open and you get leakage
What I would do if I want to prevent leaks at part throttle .. flip the stock BOV around .. make it into a pull type BOV .. trust me .. it holds more than 26psi (I tested till then and stopped )
Since the springrate for the DV is fixed .. you'll get flutter at light throttle liftoffs
Oh do be careful .. if you're using a EBC .. there'll be no more boost taper
Most aftermarket BOVs (if not all) are pull type valves .. ie it uses vacuum from the manifold when you close throttle to pull the valve open .. that's why after market BOVs don't leak .. because the pressure pushes the valve seats tighter when the UICP is pressurised ..
Stock BOVs are push types .. pressure on the UICP pushes the valves and if the pressure exceeds the spring rating, the valves open and you get leakage
What I would do if I want to prevent leaks at part throttle .. flip the stock BOV around ..
make it into a pull type BOV .. trust me .. it holds more than 26psi (I tested till then and stopped ) Since the springrate for the DV is fixed .. you'll get flutter at light throttle liftoffs
Oh do be careful .. if you're using a EBC .. there'll be no more boost taper
I'm a little confused about this.
Aren't aftermarket BOV's also "push-type" as you describe?
The plunger goes up against a spring in the head of the BOV just like in a diverter.
Most aftermarket BOV's also use the pressure from the UICP to push against the spring to help the vacuum pull the plunger upwards.
My point: Isn't it a combination of push type (UICP pushing against plunger) as well as pull type (vacuum pulling plunger upwards) ?
I'm a little confused about this.
Aren't aftermarket BOV's also "push-type" as you describe?
The plunger goes up against a spring in the head of the BOV just like in a diverter.
Most aftermarket BOV's also use the pressure from the UICP to push against the spring to help the vacuum pull the plunger upwards.
My point: Isn't it a combination of push type (UICP pushing against plunger) as well as pull type (vacuum pulling plunger upwards) ?
Aren't aftermarket BOV's also "push-type" as you describe?
The plunger goes up against a spring in the head of the BOV just like in a diverter.
Most aftermarket BOV's also use the pressure from the UICP to push against the spring to help the vacuum pull the plunger upwards.
My point: Isn't it a combination of push type (UICP pushing against plunger) as well as pull type (vacuum pulling plunger upwards) ?
HKS SSQV
This is when the UICP is pressurised .. the pressure acts on the valve sealing it against the valveseat ..
When it vents .. at throttle lift off the vacuum pulls the valve open against the spring ..
I get it now thanks.
Funny, I don't think my blitz dual drives on my other car are like that.
They may be push types.
You'll like it.. running it since I had the car
Last edited by gunzo; Aug 2, 2007 at 07:00 AM.
As I recall (its been awhile) it comes with an IAT sensor since you cant use the one built into the MAF. Non US cars come with an intake manifold mounted IAT that we only have an undrilled bung for. I am gonna go read the MAFTpro thing again and see if I can decipher some details.
You could also hum a few bars and fake it...I have tuned plenty of Hondas without using the IAT.
edit:
Straight from their website-
Air Temp:
Air temp correction, setting is added to the regular system tune value. Note this adjustment is in addition to the Speed Density algorithm's temperature compensation. Additional adjustment can be required to adjust for atomization characteristics of injectors, or heat-soak conditions.
You could also hum a few bars and fake it...I have tuned plenty of Hondas without using the IAT.
edit:
Straight from their website-
Air Temp:
Air temp correction, setting is added to the regular system tune value. Note this adjustment is in addition to the Speed Density algorithm's temperature compensation. Additional adjustment can be required to adjust for atomization characteristics of injectors, or heat-soak conditions.