Another S/C'd member worried about his AFR

[largeorangefont]

Originally Posted by LtNoogie

I have not heard audible evidence of knocking like I did before I filled up with 91 octane. The only reason that I am guessing there is knocking is the ingition timing being retarded. I know others have to add octane boosters to stop their audible knocking.

I'll reset the ECU on Sunday and try the tests suggested.

Yea you are going to need to run 91 all the time now. Do you have the wiring diagram for your black box? It sounds like my suspicion that Blitz changed what the black box does might be true according to Camelll.

[eTiMaGo]

Originally Posted by camelll

Are you using the r-vit? If so get on it and let us know how it works.



This information is for the R-fit and not the r-vit and (can be used in conjunction though) is from 2004 but it is the latest updated list they have on the blitz website page 25, does not show the ncp91. This could be a little out of date but .

I am curious if someone is gonna try the r-vit though to see if it is gonna work.

It should work, in theory when you're in open loop you can tweak all you want within the limitations of the fuel pressure and injectors?

Originally Posted by largeorangefont

Yea you are going to need to run 91 all the time now. Do you have the wiring diagram for your black box? It sounds like my suspicion that Blitz changed what the black box does might be true according to Camelll.

Yeah I am still not sure how the clutch gets the information from the gear... sounds like it ties in to the starter circuitry (the part which requires you to press the clutch on a manual, or have the auto in P or N before the engine will crank).

Anyway, looking at the new data Pavel logged, it looks like there is a correlation between throttle % and closed loop mode. It was a pretty short run but it looks like above 75% throttle, the system switches to open loop. So, perhaps the blitz unit is reporting 100% throttle to the ECU no matter what, once it kicks in the SC?
Now this is something that Long can check with the scangauge, see what is the reported throttle angle once the SC kicks in... If it jumps from actual throttle position (say 50%) to a much higher value, then bingo, we know how to trigger open loop safely

[changchewsoon]

Hi,

I hope its OK for me to post here although I'm running a boosted Vios rather then a charged one, I have a Greddy Informeter Touch which plugs in to the OBDII connector to monitor all engine parameters, and I've also got a Innovate LC-1 Wideband O2 to monitor my air/fuel ratio.

I just want to share with everyone that by using E-Manage Blue, my tuner is able to get the ECU to run at a constant A/F ratio of 12 during WOT and a AF ratio of 14 during close loop. My wideband O2 display confirms this.

I'm currently using the base + ignition + injector harness for the E-Manage.

Hope the dyno chart is able to provide a better idea, hope it helps.

Please do not hesitate to ask me if you need any information, I'll try my best to share.


http://4.bp.blogspot.com/_RQcAxTVtNR...Dyno-Chart.JPG

[largeorangefont]

Originally Posted by eTiMaGo

It should work, in theory when you're in open loop you can tweak all you want within the limitations of the fuel pressure and injectors?



Yeah I am still not sure how the clutch gets the information from the gear... sounds like it ties in to the starter circuitry (the part which requires you to press the clutch on a manual, or have the auto in P or N before the engine will crank).

Anyway, looking at the new data Pavel logged, it looks like there is a correlation between throttle % and closed loop mode. It was a pretty short run but it looks like above 75% throttle, the system switches to open loop. So, perhaps the blitz unit is reporting 100% throttle to the ECU no matter what, once it kicks in the SC?
Now this is something that Long can check with the scangauge, see what is the reported throttle angle once the SC kicks in... If it jumps from actual throttle position (say 50%) to a much higher value, then bingo, we know how to trigger open loop safely

Yes, Long could check that, but I think the system is more sophisticated than that. There are many other systems that require correct and accurate reporting of throttle position.

There is more than one metric that triggers open loop. Generally speaking there is RPM, Load, and TPS. Depending on the ECU, the car could be using one or all 3 as reference points.

[largeorangefont]

Originally Posted by changchewsoon

Hi,

I hope its OK for me to post here although I'm running a boosted Vios rather then a charged one, I have a Greddy Informeter Touch which plugs in to the OBDII connector to monitor all engine parameters, and I've also got a Innovate LC-1 Wideband O2 to monitor my air/fuel ratio.

I just want to share with everyone that by using E-Manage Blue, my tuner is able to get the ECU to run at a constant A/F ratio of 12 during WOT and a AF ratio of 14 during close loop. My wideband O2 display confirms this.

I'm currently using the base + ignition + injector harness for the E-Manage.

Hope the dyno chart is able to provide a better idea, hope it helps.

Please do not hesitate to ask me if you need any information, I'll try my best to share.


http://4.bp.blogspot.com/_RQcAxTVtNR...Dyno-Chart.JPG

This is an example of the AFR you want to see on a WOT pull guys.

What are you injector duty cycles, and are you still running stock injectors?

[changchewsoon]

I'm currently running stock injectors, but I have 2 additional injectors soldered near to the throttle body controlled by the piggy back.

If I'm not mistaken, the opening/closing time of the injectors are at around 20ms during WOT near the RPM limit.

The duty cycle is around 87% for the stock injectors during WOT near the RPM limit. I always thought that anything above 80% is bad however we've done many hours of extensive testing and the newer version of the Toyota VVT-i injectors are actually quite reliable.

We've also checked with TRD Thailand, as their Turbo Vios are also running the same stock injectors, they too have also done extensive testing on the injectors to ensure their reliability.

However, I'm not too sure whether is there any difference between JDM and USDM specs though.

[largeorangefont]

Originally Posted by changchewsoon

I'm currently running stock injectors, but I have 2 additional injectors soldered near to the throttle body controlled by the piggy back.

If I'm not mistaken, the opening/closing time of the injectors are at around 20ms during WOT near the RPM limit.

The duty cycle is around 87% for the stock injectors during WOT near the RPM limit. I always thought that anything above 80% is bad however we've done many hours of extensive testing and the newer version of the Toyota VVT-i injectors are actually quite reliable.

We've also checked with TRD Thailand, as their Turbo Vios are also running the same stock injectors, they too have also done extensive testing on the injectors to ensure their reliability.

However, I'm not too sure whether is there any difference between JDM and USDM specs though.

Great info. Just to clarify, the 87% duty is NOT while using your extra injectors correct?

Most modern injectors you can run in the low 90% range without issue, so I would say you are fine at your current power level.

[changchewsoon]

Yes actually it is 87% duty while using the extra injectors.

I do agree with you on running on the low 90% range for modern injectors, as a matter of fact we actually pushed the stock injectors pass the 97% mark and it actually holds up pretty well.

[LtNoogie]

I did not get a chance to run the test and I'm off to D.C. for a week of work.

[Loren]

Without taking the time to read through this whole thread... some thoughts.

What does "open loop" mean? It simply means "not closed loop". Closed loop means that the ECU is using feedback from the O2 sensor to fine tune the fuel mixture and keep it at stoich (or, I suspect maybe even a tad lean on the Yaris, but that's just a guess). In open loop, the ECU is most definitely still making adjustments and still has complete control of timing and fuel, it's just ignoring the O2 input and using intake air temp (temp affects density, a critical factor), air flow, and RPM to look up the appropriate fueling and timing in a table. By design, this will always be a rich mixture, and timing will be "conservative", similar to that of a distributor with no vacuum advance.

Now, I was thinking about all of this worry about being lean on these SC cars. (because I noticed one for sale for $2500 and had a fleeting moment where I was thinking about it... until I remembered that I don't have the money) Remember, even though your car is "forced induction" with the SC kit, it's a VERY light boost. What is it? 4psi? Maybe 6psi? Guess what? The real problems with fuel and spark retard don't happen until way beyond there. You guys are applying the kind of fear that one should have with a medium-high boost turbo to a low-boost supercharger, and I really don't think it's warranted at all.

I'd rock a Blitz SC right out of the box. Run premium fuel and be happy. Life is too short for such paranoia!

[Nexus1155]

See, but thats the thing, you can get one of these out of the box be happy and be fine, but not run optimally. I think thats what everyone is looking for. And it is such a small amount of boost that supercharger is running.

What I am trying to think now is that if you do have extra injectors it might be the only feasable option to get the AFR correct for now until someone finds an interceptor for the O2 Sensors, but will it cause a rich condition and trigger a CEL as well!. Damn these cars to hell

[Loren]

Originally Posted by Nexus1155

See, but thats the thing, you can get one of these out of the box be happy and be fine, but not run optimally. I think thats what everyone is looking for. And it is such a small amount of boost that supercharger is running.

What I am trying to think now is that if you do have extra injectors it might be the only feasable option to get the AFR correct for now until someone finds an interceptor for the O2 Sensors, but will it cause a rich condition and trigger a CEL as well!. Damn these cars to hell

Okay, I'll buy that (though I don't think there's THAT much more to gain by tuning the fuel WITHOUT adding more boost). But, the topic of this thread was, I thought... "worry" about being too lean. Worrying, I assumed about possible detonation and engine damage, not about leaving a little bit of power on the table.

One last thought: Tuning to get every last HP out of an engine is an art as much as it is a science, it's hard to do. If you screw up in the process of tuning it, you can do some damage. And once you've tuned it, you're right on the ragged edge of... trouble. Unless you're running a race team with a budget to replace the engine when it breaks, it's a lot smarter to go ahead and leave a little bit of performance untapped. Leave some margin for error. Leave the tune such that if your fuel happens to be 88.5 octane one day instead of 91, the engine still won't detonate. Out of the box, the Blitz is giving you 20% more power than stock... be happy! Be RELIABLY happy! (isn't that why you bought a Toyota?)

What's left on the table with the Blitz, anyway? Another 2%. Is it really worth all of the extra money, hassle and potential reliability issues for 4-5 hp? Every wire you cut and splice, every wire you add, every piece of hardware you add is another potential point of failure on your car.

[PETERPOOP]

They are saying there is possibly 20-30hp to gain with a tune.

[Loren]

Originally Posted by PETERPOOP

They are saying there is possibly 20-30hp to gain with a tune.

I'll believe that when I see it.

Let me qualify that. The bolt-on, out-of-the box Blitz SC kit with fully tuned and optimized fuel and spark. The initial installation is only good for about 25%, or 25-30 hp. No way is optimizing the fuel and spark going to DOUBLE that. You'll find another 3-8%... maybe as much as 10% or so, just like you would by tuning the car without the SC. That's the factory's margin of safety that you're playing with.

Now, you might see something close to that with a lot of OTHER additional mods, like a complete free-flowing intake, larger TB, better flowing intake manifold, some head work, a good header and a complete free-flowing exhaust. But, that's an awful lot of other stuff that doesn't really fall into the category of "fuel and spark tuning". And, even with all of that, I still don't think you're going to DOUBLE the output of the SC without raising the level of boost.

[Nexus1155]

Ehhhh I don't know about factual numbers, but if you are running stoich on a supercharger you are being robbed of power.

Get the fuel to the correct AFR and increase ignition as it will be more allowable, you will be golden. But obviously at this point you know you are being robbed of precious power that you could have.

Tuning takes some skill and knowledge, but it is not a rocket science.


As Loren said as well you would need to upgrade the flowing parts of this engine. I think the real kicker is to see the results after the throttle body upgrade..

[eTiMaGo]

as far as I understand, 14.7 stoichical air fuel ratio is the sweet spot for best catalytic converter effiency, not necessarily power?

But yes, Loren does have a good point, tuning for maximum power does reduce the safety/reliability overhead that Toyota has engineered into this car. Caveat Emptor, as the saying goes

[kurokoma-kun]

Originally Posted by Loren

I still don't think you're going to DOUBLE the output of the SC without raising the level of boost.

Ok, well I do like what Loren said about leaving sleeping superchargers lie, as I said the same thing a few pages back

BUT, since he raised the topic of added boost, and mad science also appeals to me (and we have already strayed so far from the original topic) I'd appreciate it if you'd all give opinions on my theoretical question... NST is considering developing a set of pullies for the s/c application (overdrive crank and underdrive water pump, the only configuration that will fit in the given space). Mike estimates the combination of the two could produce an additional 2 psi of boost, or up to 20 whp. The way I understand it, boost works on a geometric progression--you get more power out of those last 2 psi than the first 2 in other words--so these pullies could nearly double the hp ouput.

I expressed interest in letting my car be the guinea pig--nothing difficult about changing out some pullies--but no one can say for sure whether the fuel system can keep up, and for all the reasons mentioned I hesitate to tackle a fuel system revamp...

Based on what you have all derived from this discussion, what are your opinions? Could I at least go ahead and be the test mule without too much danger to the engine?

I think we decided the fuel injectors are max 230cc, max fuel pressure at the rail is 46.9 psi, but even with these figures I'll be damned if I can find any way to calculate the max hp for sure.

[kurokoma-kun]

Oh i know, thanks! I want to buy that one yarisdarkness is parting out but I think he's still organizing prices and so forth... if I dont hear soon I already have one picked out on ebay.

The NST pullies are still in the R+D phase anyway, I talked it over with Garm before this thread came up, so I plan to continue gathering info and insights before committing to anything.