MAFT-Pro Tuning Thread Unofficial and Uncensored

[Adjuster]

Thanks man.. The math works out to that 77% number, but I'm with you on the "I'd rather tune with less fuel pressure" than possibly raise the timing up to where it would cause problems.

Does anyone know how much the timing actually changes across the KS signal rate? (So as Hertz rate increases, the timing should decrease, and does the TCCS use pressure at all in setting timing? I don't think it does, but I'm not an expert on the TCCS either.. Perhaps JJ could chime in here?)

At what point do the injectors fail to have a good atomization pattern as the pressure goes down? I realize that the fuel droplets will be larger as the pressure drops, but what reall size difference will happen between say 30psi, and running them at 20psi? (Educated guess here, it's going to make some fuel drop out of the airflow at low rpm/idle, and that's going to possibly make it run poorly, especially when it's cold, much like a carburated engine.)

There is a point too where the fuel pressure will not drop down, no matter how much you adjust the regulator... (I believe it's higher than 20psi. So really, IIRC, the lowest fuel pressure I could get before was 24psi.. ? It's been awhile since I was adjusting the pressure to see what it was going to do, and how low it would go... The engine died on the 550's IIRC at about 24psi, so perhaps on the larger injectors, it might be able to be adjusted lower too? IDK.)

But, this puts me into a guessing mode on what mainscale to pull... (I know there is a math formula to calculate what injector flow is at like 43psi, and then what it would be a lower psi rates.. but I'm no math wiz.. I'll look at RC's site, IIRC, there is a calculator there..)

Thanks... LOL

Anyone else think pulling 77% is just crazy?

Oh, and my motor really does displace 3.24L exactly.. (Well, there are a few decimial points difference, but that's what it displaces )

84mm bore, and 97.5mm stroke IIRC.

Did the RC calculator again, and I remember doing this before, and choosing the 780cc injectors for this reason.
To get a 650crank shaft HP capable 7MGTE, you really need to have injectors close to this size.
At 55psi final fuel pressure. (Assuming I'm adding 25psi of boost to 30psi base pressure..)
RC calls for 759cc injectors.

Just for fun, let's look at 550's and this calculator.
To get 450 crank hp, you need 526cc injectors being fed 55psi fuel. Pretty conservative numbers as most 7MGTE's with 550's and our engine/fuel setup generally are putting out 420rwhp at 18psi on a 60-1 bolt on, and some have made more, or less than these figures on 550's and similar fuel pressures. (Base of around 30psi with the 20 to 25psi of pressure added during boost.)

I really don't think I'm that crazy far off on the numbers considering that people have made more power than 650 with injectors this size, and less sophisticated controls than the Translator Pro... We at least can see where the ignition advance is going, and even if I'm brave enough, pull some timing advance to limit detonation. (I've thought about adding a methanol spray system that starts adding spray at 20psi, much like Mike has done to his Supra.) I'd like to get this to work on gas alone however if possible. (And I have some Toulene that I can add to raise octane up when I'm running high boost anyway... Might build a system that sprays pure toulene v/s methanol... Just need to find something that is resistant to that suff, it's nasty when it's pure..!)

 

[dbsupra90]

as reference, at 26psi bfp your injectors will actually flow like 603cc.

bfp/43.5psi (flow rate psi)=x
sq rt of x= y
y * cc rate of inj = flow

as far as how low you can adjust fuel pressure, that will depend on what regulator you are running. my paxton will go down to ~25psi. a lot of the aeromotive will only go down to ~30psi.

i believe it was pte that told me fuel pattern will suffer below 26psi but not certain.

 

[Adjuster]

Well, that makes sense. My Areomotive regulator did not want to go below 24psi IIRC....

New plan. Adjust the fuel pressure down to 25psi (With the vac line clamped off.), and then pull mainscale untill the Vf voltage is about 2.5v, and it should be as good as I'm going to get base wise with these injectors.

Any guesses on mainscale values at this new "target" base fuel pressure?

Should be interesting to see where it ends up.

One more question since I'm here. (And I think I might already know the answer... to some extent...)

The more mainscale you pull, the higher the FC point is going to be right? (Taking into account, that high air flow conditions at lower rpm seems to trigger FC too...)

Theory is that less Hz rate will be needed at idle, even with the low fuel pressure due to the higher fuel flow rate of the injectors. That leaves more headroom for adding injector duty before the 1500hz signal point where the TCCS cuts the fuel... (At higher rpm of course.)

At the risk of running too much spark advance of course.

Or having the clamp/limit the signal going to the TCCS..

And the nifty idea Turbo Bob posted about adding TPS signal voltage when the pressure (MAP) exceeds 105 at lower rpm.. fooling the TCCS Fuel cut, and adding more fuel where it's needed in the mid throttle boost ranges... Very cool idea indeed, and one that I agree the Supra needs for sure. (As Doward theorized, he says that many MK3's have BHG's or other problems due to extended mid boost running on "lean" AF's since the TCCS is designed to run lean stock in mid throttle boosted conditions..)

The extensive coatings I added to my motor are to help control heat caused by dentonation, and for future lean operation in "cruise mode" at say 16:1 ratios.. I know the coatings already saved the motor when it detonated bad going out of Vegas a few years ago, wiped out two spark plugs, but no piston or cyc bore damage at all... Not luck, but coatings doing their job. (Forged pistons and billet forged rods don't hurt, and neither does the extra oil pressure this engine makes now... )

Run any engine that way long enough, however, and it's going to melt down eventually.

 

[thedave925]

You've got the right idea. Now the trick is to balance out pulling fuel with the Maft and regulator.

Quick recap:
The idea behind the Lexus AFM is to allow more air through the engine without hitting fuel cut. If you don't add 550cc injectors, you'd run rich.

Taking back mainscale on the Maft-Pro is much the same idea. More air and fuel allowed before fuelcut.

Run rich, better safe than sorry

 

[pimptrizkit]

You've got the right idea. Now the trick is to balance out pulling fuel with the Maft and regulator.

Quick recap:
The idea behind the Lexus AFM is to allow more air through the engine without the engine seeing the extra air,raising the spot your hitting fuel cut. If you don't add 550cc injectors, you'd run lean.

Taking back mainscale on the Maft-Pro is much the same idea. More air and fuel allowed before fuelcut.

Run rich, better safe than sorry

fixed it for yeah

the corect way would be tune with fuel pressure till you get a pressure you like, and a good afr mostly afronce the afr is right around were it needs to be fine tune with the map and the ecu should correct for the rest when it's that close in closed loop.

 

[GrimJack]

My IAT is in the same place, this after I put it in between the valve covers initially, which turned out to suffer from heat soak bigtime. This spot is awesome. I figure if the air going in picks up some heat going by the turbo it'll expand a bit, meaning less air goes in than I expect, less air = richer, and I'd rather have it error on the side of caution.

MAP sensor should be ok, I guess - I put mine on the passenger side wheelwell, and put a T in the big U shaped line on the front of the intake manifold. It's close, and it's a big source, if there is any difference in measurements due to the pipe size and location I figure this is about as safe as you can get.

My base Fuel Pressure with the vac line off is 27psi. I found this by adjusting it until I got the best idle.

The filter on the ISC is fine, that's how I have mine set up as well.

You have your PLX hooked up for automatic WOT adjustment, right? That's freaking awesome, I love that feature.

When I was tuning, I just did a bunch of datalogging and kept adjusting until I got the vF right around 2.5 - that way the stock ECU is happiest.

I put the IAT sensor in the mid IC pipe from the cooler to the upper IC pipe... so should not be heat soak issues.
Also located the MAP sensor just behind the right head light, near the IAT sensor so the wires were easy to route. My vac line also has the BOV's on it, and is coming off the intake manifold at the front port where the fuel pressure regulator stock is sourced. (Appears it's down a tube cast into the manifold, so it should be a good source right?) Is the BOV's on there going to cause me grief however on the signal?

Here is a photo. The vac line going to the BOV's also has a T fitting going to the MAP sensor that is facing downward under the plastic headlight hood gasket trim. The IAT sensor is sticking out of the IC pipe right there too.

Ok, to go back over this again.
1) At idle, with the hose to the AFPR clamped shut, base fuel pressure is going to be 30psi. (Will check to make sure it's still the same as before.)
2) TPS is new with rebuild, will confirm it's adjusted right if there are issues there, but should not be. (As per TSRM for voltage.)
3) No concerns about ICS with this right? It just has a filter clamped over the intake port, and should control idle speed air like normal, and be "metered" by the speed density calculation from the Translator Pro right?
4) Have a good stock O2 sensor, in "stock" location, and PLX Wideband in another bung further down the exhaust where it's cooler. Plan on using the TCCS/Stock O2 for idle and running around, and will only tune the WOT for now with the Translator Pro. (Eventually, might use the low and mid ranges and build up the fuel map from that data, but for now, I just want to get this car running again..)
5) All other parameters as indicated in the manual/etc.

Also plan on running the latest 4.8 version of the software, and have the 4.4 version of the User Manual and 4.80 Online guide/worksheet to take notes and keep reccords..

Anything I'm missing?

 

[dbsupra90]

You have your PLX hooked up for automatic WOT adjustment, right? That's freaking awesome, I love that feature.

just be sure when you have it do the correction you dont have it in emulation mode. if the wideband were to freakout it could pull the a/f fasely lean.

i know there are limits you can set for max rich and max lean, but id rather be safe than sorry. i just go back thru the logs and adjust to the projected values.

 

[tookwik4u89]

You do need to have a good ball park tune for insurance, but the WOT tracking is the shit!

 

[Adjuster]

Ok, I'm almost cringing to ask this, but I'm reading about VE... And how if I can build a VE table, that the Translator Pro will even work better than just the more generic user tune values...

Anyone doing this. (Appears Doward asked this awhile back, but not much response other than from Turbo Bob..)

With the larger injectors, and funky displacement on my engine, I think going the VE route as I do more work with this setup might have some real advantages. See that excel based worksheet to develop a custom VE for each motor.. Very cool stuff.

Yes, I agree lean is bad, and running rich is safe. No worries there. I do need to get two more gauges minimum.. A oil pressure gauge with peak hold, and a fuel pressure gauge with a warning feature. (And most likely peak hold too...) I see there are some green LED backlit ones with these features now at pretty good prices.. (My Omori ones in 60mm were way too much money...) LOL

PLX has a programable one that can be shifted between multiple sources, and that's possibly what will occupy the lighter socket hole one of these days.. (And I'm looking at adding a few "extra" power ports down on the passenger side that can be tucked out of the way between the passenger seat and the tunnel, and wire them up on their own power supply/relay.)

Bummer is that they predict snow here over the weekend... It will be just my luck to get the Supra running, and then not be able to enjoy it.. (Wide summer tires and snow do not go well together... LOL)

 

[drjonez]

Ok, I'm laughing, but I still don't have my car running, and I've got nobody to blame but myself..

Did some more math.. (Scary, as I'm no rocket scientist, and do not claim to be by any stretch of the imagination..)

New injectors are 780cc PTE sourced Delphi injectors.
Stock is 440cc. Denso's..

Fuel pressure being a constant... Should provide the following mainscale data.

The new injectors are 340cc larger than the old, about 77.3% larger is 340.12cc... So the mainscale reduction should be set at -77.3% right? (Assuming that it can be cut down to that, or -77% if not.)

sure, mainscale SHOULD be -77%....but this is reality. AFM corrections of this magnitude are not reasonable (for a variety of reasons- fuel, timing, etc.).

the real question is WHY are you running 780s? if you need that much fuel, you should not be attempting it with a piggyback (just MNSHO).

Also, my motor displacement is 3.24L. And reading on here, I believe the TranslatorPro will accept the 3.24L info.. (Or will it just accept 3.2L?)

sure will accept that. remember the MAFT pro runs on a variety of cars.

Speed density setup with timing monitor/control wires hooked up and boost control too.

I put the IAT sensor in the mid IC pipe from the cooler to the upper IC pipe... so should not be heat soak issues.
Also located the MAP sensor just behind the right head light, near the IAT sensor so the wires were easy to route. My vac line also has the BOV's on it, and is coming off the intake manifold at the front port where the fuel pressure regulator stock is sourced. (Appears it's down a tube cast into the manifold, so it should be a good source right?) Is the BOV's on there going to cause me grief however on the signal?

Here is a photo. The vac line going to the BOV's also has a T fitting going to the MAP sensor that is facing downward under the plastic headlight hood gasket trim. The IAT sensor is sticking out of the IC pipe right there too.

great location for the IAT!

your BOVs are backwards.

i would be a bit concerned about running too many things off one vac line...especially at that distance from the manifold. i would give the MAP sensor its own vac feed....again, just MNSHO.

Ok, to go back over this again.
1) At idle, with the hose to the AFPR clamped shut, base fuel pressure is going to be 30psi. (Will check to make sure it's still the same as before.)
2) TPS is new with rebuild, will confirm it's adjusted right if there are issues there, but should not be. (As per TSRM for voltage.)
3) No concerns about ICS with this right? It just has a filter clamped over the intake port, and should control idle speed air like normal, and be "metered" by the speed density calculation from the Translator Pro right?
4) Have a good stock O2 sensor, in "stock" location, and PLX Wideband in another bung further down the exhaust where it's cooler. Plan on using the TCCS/Stock O2 for idle and running around, and will only tune the WOT for now with the Translator Pro. (Eventually, might use the low and mid ranges and build up the fuel map from that data, but for now, I just want to get this car running again..)
5) All other parameters as indicated in the manual/etc.

Also plan on running the latest 4.8 version of the software, and have the 4.4 version of the User Manual and 4.80 Online guide/worksheet to take notes and keep reccords..

Anything I'm missing?

1. don't clamp the vac line, remove it.
2. a new TPS? good thinking!
3. yup, w/speed-density you can run the ISC vented....just realize your idle vac will move up/down a bit when it's running.
4. with your injectors, you'll have to do quite a bit of mid/low tuning to satisfy Vf.
5. yup. CRE's 4.8 page is amazing....use it!

 

[drjonez]

Thanks man.. The math works out to that 77% number, but I'm with you on the "I'd rather tune with less fuel pressure" than possibly raise the timing up to where it would cause problems.

tune w/fuel press first, then fine tune w/AFM corrections.

in your case, turn your AFPR down as far as it will go...

Does anyone know how much the timing actually changes across the KS signal rate? (So as Hertz rate increases, the timing should decrease, and does the TCCS use pressure at all in setting timing? I don't think it does, but I'm not an expert on the TCCS either.. Perhaps JJ could chime in here?)

nope, no one has quantified that yet.

timing vs. mass flow is inverse- MORE mass flow = LESS timing. so leaning it out (LESS mass flow) = MORE timing.

pressure? the ECU has no way of knowing MAP....only mass flow from the AFM.

At what point do the injectors fail to have a good atomization pattern as the pressure goes down? I realize that the fuel droplets will be larger as the pressure drops, but what reall size difference will happen between say 30psi, and running them at 20psi? (Educated guess here, it's going to make some fuel drop out of the airflow at low rpm/idle, and that's going to possibly make it run poorly, especially when it's cold, much like a carburated engine.)

There is a point too where the fuel pressure will not drop down, no matter how much you adjust the regulator... (I believe it's higher than 20psi. So really, IIRC, the lowest fuel pressure I could get before was 24psi.. ? It's been awhile since I was adjusting the pressure to see what it was going to do, and how low it would go... The engine died on the 550's IIRC at about 24psi, so perhaps on the larger injectors, it might be able to be adjusted lower too? IDK.)

anything above 20 psi should be fine.

...Anyone else think pulling 77% is just crazy?

yup.

Oh, and my motor really does displace 3.24L exactly.. (Well, there are a few decimial points difference, but that's what it displaces )

84mm bore, and 97.5mm stroke IIRC.

i still think you need to look into standalone....

Did the RC calculator again, and I remember doing this before, and choosing the 780cc injectors for this reason.
To get a 650crank shaft HP capable 7MGTE, you really need to have injectors close to this size.
At 55psi final fuel pressure. (Assuming I'm adding 25psi of boost to 30psi base pressure..)
RC calls for 759cc injectors.

Just for fun, let's look at 550's and this calculator.
To get 450 crank hp, you need 526cc injectors being fed 55psi fuel. Pretty conservative numbers as most 7MGTE's with 550's and our engine/fuel setup generally are putting out 420rwhp at 18psi on a 60-1 bolt on, and some have made more, or less than these figures on 550's and similar fuel pressures. (Base of around 30psi with the 20 to 25psi of pressure added during boost.)

I really don't think I'm that crazy far off on the numbers considering that people have made more power than 650 with injectors this size, and less sophisticated controls than the Translator Pro... We at least can see where the ignition advance is going, and even if I'm brave enough, pull some timing advance to limit detonation. (I've thought about adding a methanol spray system that starts adding spray at 20psi, much like Mike has done to his Supra.) I'd like to get this to work on gas alone however if possible. (And I have some Toulene that I can add to raise octane up when I'm running high boost anyway... Might build a system that sprays pure toulene v/s methanol... Just need to find something that is resistant to that suff, it's nasty when it's pure..!)

eh, be careful with how much boost you're trying to run on pump gas....

 

[dbsupra90]

i would give the MAP sensor its own vac feed....again, just MNSHO.

i agree 100%. mine is fed directly off the intake manifold. i would go one step further and put one of those ufo looking vac filters on the line too. and dont forget- dont mount the map sensor with the vac port facing up!

 

[drjonez]

Ok, I'm almost cringing to ask this, but I'm reading about VE... And how if I can build a VE table, that the Translator Pro will even work better than just the more generic user tune values...

Anyone doing this. (Appears Doward asked this awhile back, but not much response other than from Turbo Bob..)

With the larger injectors, and funky displacement on my engine, I think going the VE route as I do more work with this setup might have some real advantages. See that excel based worksheet to develop a custom VE for each motor.. Very cool stuff.

why cringe? the VE tuning is a great way to build a "correction table" for your specific engine.

use the tuning parameters to get your car to run well....then use the spreadsheet to apply those corrections to a VE table....

 

[atlpd3147]

I got a quick question(s) regarding some parameters and what the numbers mean.
In the system setup page under afterstart enrichment you can input 0 to 20. What are those numbers representing? % in fuel increase? Time that the enrichment will last in minutes? The manual doesn't really explain it completely.
And also in the system setup page under af trdelay how are the numbers measured. Seconds? Minutes? Or what?
Thanks for any replies to my questions.

 

[CRE]

I can't remember if I got this from Bob or if I just drew my own conclusions... It seems that afterstart represents an arbitrary duration AND increase. The higher the afterstart value is set the more fuel it'll start out with for enrichment. Then, as the time remaining shortens the amount of added fuel lessens as well.

AFTrDelay, according to my notes, is measured in seconds.

Are you using the 4.4 manual? What version of software are you running? If you haven't seen it already, this may be of some use: MAFT Pro 4.80 Guide It's a work in progress.

 

[Adjuster]

Thanks for the feedback. If the MAP sensor Causes me any idle/running problems, I will route a seperate hose just to it as you guys suggest. (It is a pretty good size diameter hose, slightly larger than stock Toyota stuff, and about the same size as the GM 3 Bar port, so flow is not a problem, but I was worried about the BOV's on there.)

Think those Bosch bypass valves are backwards eh? If you mount them the other way, they leak when you don't want them to, and they do not bypass when you can benefit from it. (Under pressure, if they are backwards, they will often leak at boost pressure over about 15psi.) Also, under no boost, IE: Vac conditions in the intake, they are pulled slightly open, and create a short cut from the air filter to the intake throttle body that bypasses the turbo/FMIC/IC pipes.. Improves throttle reponse in theory, and I think it worked both on my stock engine when I did this years ago, and later on the subsequent stroker motor(s).

In reality, unless there is a leaking diaphram on the Bypass valve, the pressure in the hose to them and the MAP sensor should be the same, but I agree that a steady pressure signal to the MAP sensor is important to this all working out right.

Oh, the sensor is facing port down... (It's zip tied to the underside of the plastic shield behind the headlight where it should be cooler, and running the wires to the IAT and the MAP less than one foot apart made it easy to install the Translator Pro..

I'll have to buy some more Earl's hose, and a few more fittings if I need a seperate line..

The money pit is never full..

 

[atlpd3147]

I can't remember if I got this from Bob or if I just drew my own conclusions... It seems that afterstart represents an arbitrary duration AND increase. The higher the afterstart value is set the more fuel it'll start out with for enrichment. Then, as the time remaining shortens the amount of added fuel lessens as well.

AFTrDelay, according to my notes, is measured in seconds.

Are you using the 4.4 manual? What version of software are you running? If you haven't seen it already, this may be of some use: MAFT Pro 4.80 Guide It's a work in progress.

ive got the 4.80 manual guide and im using version 4.65 i will change to version 4.80 after i get a handle on a few parameters in 4.65

 

[drjonez]

...Think those Bosch bypass valves are backwards eh? If you mount them the other way, they leak when you don't want them to, and they do not bypass when you can benefit from it. (Under pressure, if they are backwards, they will often leak at boost pressure over about 15psi.) Also, under no boost, IE: Vac conditions in the intake, they are pulled slightly open, and create a short cut from the air filter to the intake throttle body that bypasses the turbo/FMIC/IC pipes.. Improves throttle reponse in theory, and I think it worked both on my stock engine when I did this years ago, and later on the subsequent stroker motor(s)...

yup, they are opening against the flow that you're trying to bypass. from my exp running the bosch valve that way never responded as it should and "hooted" as well....

ive got the 4.80 manual guide and im using version 4.65 i will change to version 4.80 after i get a handle on a few parameters in 4.65

you may want to jump to 4.8+ anyway. many of the parameters have labels....

 

[Adjuster]

LOL, the "Hooting" is them working....

Installed the other way, they will leak boost pressure, even if they are sourced from the Porsche 996 part number with the stronger spring than the volvo/saab/audi part numbers. (Not sure, but the RS6 setup might use the stronger spring valve too.. would have to check, but it's not worth looking it up.. )

I think they work fine. When you close the throttle, and the pressure spike starts to build, they suddenly recieve the heavy vac signal down the hose from the intake manifold, and are pulled open, release the high pressure spike back into the intake/turbo... Not that important now that the car is speed density, but why throw away the pressurized air when you can blow it over the compressor turbine anyway?

And the shortcut off boost really works. (Thus the hooting noise right about the zero point on pressure, the manifold pressure change is closing the valve, and the air flowing through it will squeel and hoot depending on how long it's barely held open by low intake manifold vac. pressure.)

One more thing. When they are installed the right way, like mine, they are held closed by high boost pressure untill there is a strong vac signal to open them. This prevents leaks of pressure back into the intake. (And as I mentioned, even the Porsche spec ones tend to leak about 15psi if they are installed "sideways"... The spring just can not hold more pressure.)

I think there are other bypass and blow off valves that flow more than these, and your Tial one is a good example of a fast acting vented to atmosphere valve that is not leaking under vac, and opens up to vent pressure between shifts... But it's not apples to apples. Your Tial is a BOV. The bosch units are bypass valves, and were always meant to leak/open either way depending on manifold pressure/vac changes/conditions.

Back on topic, have you heard anything from Bob about the part throttle boosting mod? It would be great to have the ability to set up parameters that fool the TCCS into thinking that the TPS is open more than it really is when your building boost at lower rpm/tps, where the TCCS is designed to run lean, and really should not be.

Or should I just tune there by logging my car, and then add more fuel to those conditions. (I'm thinking the TCCS closed loop running is still going on, and that it would not allow me to add fuel very well unless I convert the system over to part/mid/high throttle AF tracking, and build fuel maps from idle to redline based on that data.)... It appears working on the VE would be a better approach to take without the software option you guys were talking about.

Thanks

 

[drjonez]

LOL, the "Hooting" is them working....

Installed the other way, they will leak boost pressure, even if they are sourced from the Porsche 996 part number with the stronger spring than the volvo/saab/audi part numbers. (Not sure, but the RS6 setup might use the stronger spring valve too.. would have to check, but it's not worth looking it up.. )

I think they work fine. When you close the throttle, and the pressure spike starts to build, they suddenly recieve the heavy vac signal down the hose from the intake manifold, and are pulled open, release the high pressure spike back into the intake/turbo... Not that important now that the car is speed density, but why throw away the pressurized air when you can blow it over the compressor turbine anyway?

And the shortcut off boost really works. (Thus the hooting noise right about the zero point on pressure, the manifold pressure change is closing the valve, and the air flowing through it will squeel and hoot depending on how long it's barely held open by low intake manifold vac. pressure.)

One more thing. When they are installed the right way, like mine, they are held closed by high boost pressure untill there is a strong vac signal to open them. This prevents leaks of pressure back into the intake. (And as I mentioned, even the Porsche spec ones tend to leak about 15psi if they are installed "sideways"... The spring just can not hold more pressure.)

I think there are other bypass and blow off valves that flow more than these, and your Tial one is a good example of a fast acting vented to atmosphere valve that is not leaking under vac, and opens up to vent pressure between shifts... But it's not apples to apples. Your Tial is a BOV. The bosch units are bypass valves, and were always meant to leak/open either way depending on manifold pressure/vac changes/conditions.

you are entitled to your opinion. i've installed/used bosch BOVs (bypass, whatever you want to call it) mounted "the other way" on plenty of cars, w/o problems. don't forget that the BOV is seeing boost in the input inline....which is helping to hold the diaphragm closed.

Back on topic, have you heard anything from Bob about the part throttle boosting mod? It would be great to have the ability to set up parameters that fool the TCCS into thinking that the TPS is open more than it really is when your building boost at lower rpm/tps, where the TCCS is designed to run lean, and really should not be.

AFAIK it's making the next SW release. he's used it on his car, i have it in a beta SW (along with some other good stuff!). there's even talk of a standalone device to do the same thing....