From knowing nothing to having a Thunderbird supercharger on an m20b27i

[codrum]

I really need some input on this.

Sounds like your grounds may be hooked up incorrectly on the gauge, MS, or both. Make sure the wideband controller AND sensor is grounded correctly. Which wideband setup are you using? If it's one of Innovate's products connect directly to the wideband controller using their software to eliminate the gauge and MS as being the problem and use that as a baseline for comparing the gauge and MS readings.

Also it could be that the analog outputs are configured differently - usually one is setup to simulate narrowband, the other is wideband from the factory. Check to make sure the settings in MS match what the controller outputs on each analog wire.

[Ether-D]

Now, next I had the my desktop hooked up to the ms2 while it was in my car and the AFR on the computer screen was very different from the AFR on the gauge face. The gauge read 12.5-12.8 at idle and the monitor showed pretty much full rich and wouldn't move unless I goosed the throttle. It would then jump up to 13ish and then fall straight off to full rich again. Ideas?

I really need some input on this.

[Ether-D]

36# @ 55psi = 32# @ 43.5psi says this calculator:

http://www.witchhunter.com/injectorcalc1.php

[Ether-D]

There's certainly a typo in there. Now what it is, Idk. I was just looking for the 43.5 number. I get the feeling that the 34# @43.5psi is correct. Especially if the GMs of that era are run at 3.5bar. The internet says it's true.

Now, next I had the my desktop hooked up to the ms2 while it was in my car and the AFR on the computer screen was very different from the AFR on the gauge face. The gauge read 12.5-12.8 at idle and the monitor showed pretty much full rich and wouldn't move unless I goosed the throttle. It would then jump up to 13ish and then fall straight off to full rich again. Ideas?

[whodwho]

"0280155737. These injectors are commonly referred to as 36# from L67 supercharged engines but flow more close to 34 lbs/hr @ 2.5 bar or 43.5 PSI"

I have them in the MS2 as 34#.

Does look like specs are all over the place, I even seen the quote you found with the wrong bar/psi 8^)

They look like they should be 36 but you should be safe with your approach and adjust accordingly.

[The Dark Side of Will]

2.5 bar is not 43.5 psi... typo?

[Ether-D]

"0280155737. These injectors are commonly referred to as 36# from L67 supercharged engines but flow more close to 34 lbs/hr @ 2.5 bar or 43.5 PSI"

I have them in the MS2 as 34#.

[Ether-D]

***And remember this is a startup tune and in no way should you be flogging it before getting it dialed in!!***

Not flogging. Paying close attention to AFRs and being 99% very gentle. 1% experimental medium to heavy footedness.

[The Dark Side of Will]

Changing from 33 to 36lbers should literally mean dropping your req fuel value to down like 8% or so. A single value in MS changes this.

Currently your fuel map would be 8% rich if it was tuned for 33s and you put in 36s, but your afr map that megasquirt uses to adjust the fueling would pull it down to the values you put in that table, EXCEPT for areas under that map (usually 2000rpm ie idle). That is why your idle is so rich and everything else that started 8% rich just tuned itself back to exactly what you had in your afr map.

I @$$ume from this that MS "thinks" in terms of AFR rather than in terms of Lambda, as an 8% change in fuel flow is an 8% change in AFR, but is NOT an 8% change in Lambda.

[whodwho]

You should be able to find the flow on the injectors by the part number use the figures for 43.5psi pressure, post up the number if you are not finding solid figures.

You will want to adjust your req_fuel over just altering the VE table, other settings are based on req_fuel as well.

If you are finding it is lean overall then raise the req_fuel, if rich then lower it. You ultimately want your VE table bins at 100 and at your peak torque to be close to 100.

What is your air temps like when stone cold? 10 AFR is a bit rich, I would try starting around 11.5ish after you get the req_fuel set and VE table dialed in around idle set when all warmed up and running about 14ish at idle.

***And remember this is a startup tune and in no way should you be flogging it before getting it dialed in!!***

[The Dark Side of Will]

They can be both if the flow rating is quoted at different pressures. GM's of the era run 3.5 bar fuel pressure, but Fords run 3.3 (I think), so if swapping injectors among systems with different rail pressures, you need to rate accordingly. Even the same manufacturers run different pressures at different times. I thought BMW's ran 3.5 bar for most apps, but the S54 and I think S62 run 5.0 bar.

What fuel pressure are you running?
Converting injector flow among different pressures is easy, but the relationship is NOT linear. You can google "injector flow calculator" or something like that and find out lots of info on it.

[Ether-D]

Well, the main reason I told it 33# is because I read that the "36#" were actually 33# in disguise. But that was on the interwebz so it must be 100% true. I will up it to the right amount once I'm not scared of going lean.

[The Dark Side of Will]

Changing from 33 to 36lbers should literally mean dropping your req fuel value to down like 8% or so. A single value in MS changes this.

Currently your fuel map would be 8% rich if it was tuned for 33s and you put in 36s, but your afr map that megasquirt uses to adjust the fueling would pull it down to the values you put in that table, EXCEPT for areas under that map (usually 2000rpm ie idle). That is why your idle is so rich and everything else that started 8% rich just tuned itself back to exactly what you had in your afr map.

You can leave the req fuel the same and just tune down your idle fuel map, or restart with the same 33lb map and tune down the req fuel 8% (what I would advise).

Why do you advise that? While it's possible to tell the computer that he's running pretty much any injector flow rate and tune around it in the VE tables, why bother? Put the right injector flow rate in and then you don't have to remember later what you lied to the computer about.

[Ether-D]

So the tune is mostly Whodwho's base tune that comes with the whodwho ms2. I've adjusted the idle pwm somethingerothers to get the idle down and told it that I have 34# injectors and that's about it. I've driven it about 2 miles. I've stepped on it a few times and the AFRs stay real good when getting on it. I didn't hear any pinging this time.

[Q5Quint]

If it pings pull back timing in those spark bins. If it is too rich (why do you need 10:1 at idle? Does it idle better? I feel like my old beast used to idle best a little lean... at 15:1 or so?

Do a logged drive and autotune to the afr table you set keeping it rich 12:1 or so while in the power areas for safety. If you feel 'ping' or are scared pull timing back from the timing map.

Not sure what idle sensor you are using but the tuning instructions for both are here: http://www.megamanual.com/ms2/tune.htm

Changing from 33 to 36lbers should literally mean dropping your req fuel value to down like 8% or so. A single value in MS changes this.

Currently your fuel map would be 8% rich if it was tuned for 33s and you put in 36s, but your afr map that megasquirt uses to adjust the fueling would pull it down to the values you put in that table, EXCEPT for areas under that map (usually 2000rpm ie idle). That is why your idle is so rich and everything else that started 8% rich just tuned itself back to exactly what you had in your afr map.

You can leave the req fuel the same and just tune down your idle fuel map, or restart with the same 33lb map and tune down the req fuel 8% (what I would advise).

Edit: how does your spark map compare to other turbo/supercharged spark maps? Is it an aggressive max hp on 93 octane dyno tuned spark map? A de-tuned street version of that map?Knowing where that came from is kind of critical. Also because I want to compare the one I have heh.

This was my old turbo tune from ms1extra. It is a de-tuned version of somebodys turbo map from e30tech many moons ago. It could probably go up 5-10deg in some areas but I wanted to be 'super safe' as it was a street tune that was already shredding a stock clutch.