My PMO ITB Project

[scarceller]

Originally Posted by Trog

You would think so, but with my TOG at 13.2ms, I had to back-off on the fuel at 5500 as it was running way too rich.

Trog,

I agree with what you are seeing, here's why: These engines require the most fuel at max Torque (5000-5500RPM) range after this the VE simply drops off and they need less fuel as the RPMs increase above the max torque point. My car sees the same setup for fuel.

Just keep logging those AFRs in WOT runs and fine tune the maps.

[Trog]

Originally Posted by scarceller

Trog,

I agree with what you are seeing, here's why: These engines require the most fuel at max Torque (5000-5500RPM) range after this the VE simply drops off and they need less fuel as the RPMs increase above the max torque point. My car sees the same setup for fuel.

Just keep logging those AFRs in WOT runs and fine tune the maps.

Makes perfect sense.

T...

[CruiseControl]

This is getting very close to a thread hijack.

I have a 390cc/min injectors installed (0280 150 803 low impedence) with ITB's. Idle control is very good.
From MoTeC logged data on a Dyno Run at WOT and 304kPa fuel pressure, maxiumum fuel injector duty is 61.5% on (6960rpm), and a max period of 11.2mSec (5830rpm) this providing a Lambda reading of 0.86.
I appreciate Sal's comments above, however the Motronic is multipoint batch injection (all injectors firing at the same time), and not sequential injection. I would prefer to stay below 85% duty with sequential injection.
Based on the detail you provided I expect that you would be targeting around 260HP + at f/w. I would stay with the 36lb injectors you have.

Do your sums and all your homework !!
Paul

[dfink]

Well I tried some of my experimental mapping changes this afternoon. Going to nearly full blend takeing out the POT (IOT) The map looked like it should run but didn't run for crap. Didn't want to start when it finally did it just didn't run good. Went back to my highly modified V/E table and things were much better again.
I also tried using basically the same table I am getting good results with but leaning things out to more closely match what others are saying. Didn't run very good and went right back to the stall when the throttle is stabbed. Looks like 13.5 is right about where I need to be for a smooth idle and no stumble. I will try to post some screen captures of the maps. I also made some adjustment to the startup and warmup maps. Car will now idle without assistance but is 200 rpm lower than when warm.
I guess I must be a bit different as I have to keep the pulse width up all the way to the end. I have a fairly flat torque curve however so there is not alot of drop off.
Trog running at 14:1 at idle do you get any stumble if you just stab the throttle.

Doesn't really show much but here is my dyno run.

[mjshira]

very impressive, lots of brass to tackle this one.

[Jeff Alton]

On my ITB set up it is happiest idlling around 13.5. I still have some cold temp work to do this winter on it, but it also likes it pretty rich when air/oil temp is real low at start up. I cruise at around 14-14.5.

At wot it runs between 12.7-12.9.

On decel I have complete fuel cut down to 1750rpm, if I don't I will get a pretty good backfire in the exhaust comming off throttle at high rpm with a hot exhaust. Would not do it unless i had been running it hard and got the headers a little warmer.

Not sure if any of that helps .....

I also do not use any air control for idle. It is a little grumpy on a cold start, but I really have not spent much time there tuning. But I can fire it up, and pull away right away with out any problem...

cheers

[scarceller]

Originally Posted by dfink

Well I tried some of my experimental mapping changes this afternoon. Going to nearly full blend takeing out the POT (IOT) The map looked like it should run but didn't run for crap. Didn't want to start when it finally did it just didn't run good. Went back to my highly modified V/E table and things were much better again.
I also tried using basically the same table I am getting good results with but leaning things out to more closely match what others are saying. Didn't run very good and went right back to the stall when the throttle is stabbed. Looks like 13.5 is right about where I need to be for a smooth idle and no stumble. I will try to post some screen captures of the maps. I also made some adjustment to the startup and warmup maps. Car will now idle without assistance but is 200 rpm lower than when warm.
I guess I must be a bit different as I have to keep the pulse width up all the way to the end. I have a fairly flat torque curve however so there is not alot of drop off.
Trog running at 14:1 at idle do you get any stumble if you just stab the throttle.

Doesn't really show much but here is my dyno run.

Impressive, are these numbers at the crank or the wheels?

What is the setup of this motor?

[scarceller]

Originally Posted by CruiseControl

This is getting very close to a thread hijack.

I have a 390cc/min injectors installed (0280 150 803 low impedence) with ITB's. Idle control is very good.
From MoTeC logged data on a Dyno Run at WOT and 304kPa fuel pressure, maxiumum fuel injector duty is 61.5% on (6960rpm), and a max period of 11.2mSec (5830rpm) this providing a Lambda reading of 0.86.
I appreciate Sal's comments above, however the Motronic is multipoint injection (all injectors firing at the same time), and not sequential injection. I would prefer to stay below 85% duty with sequential injection.
Based on the detail you provided I expect that you would be targeting around 260HP + at f/w. I would stay with the 36lb injectors you have.

Do your sums and all your homework !!
Paul

Paul,
First, I'm just a stock Motronics fella and I'm here to simply learn more about ITBs and share what I know about the stock setup.

The motronic fuel injection is a batch system and it injects fuel for one cyl fire in 2 squirts, so these 2 squirts are very short duration at idle and this is why you can't oversize injectors.

So if the EFI system used for ITBs is sequential my guess is it simply puts the fuel in 'all in 1 shot' at the appropriate valve time. This would certainly help the injector better atomize the fuel at idle.

Also, the stock injectors are running in the 80% or more cycle at max torque WOT conditions.

I'm surprised to see you are using such large injectors, I'm just learning here so thanks for the feedback.

[dfink]

Trog here are my current configurations sheets. My UAP = the maxs time on and the POT = you Idle time on - This setup runs pretty good and will start and idle without holding in additional throttle. The idle is however about 200 rpm lower than when warm. I would suppose the cold oil puts a load on the engine.

[dfink]

looks like I missed the start up table. I did the screen shot but lost it somehow. I will post it later. I have to say that TimT was at least partially right in that I had to revisit the startup and warmup maps. In general I was way too rich starting up. Had to take out or reduce several areas.

Trog can you post your startup and warmup maps.

Also my maps need some fine tuning to smooth things out. To do that I am going to need an assistant to ride along and make small adjustments as I drive.

I didn't show the blend table but I am not using any blend. All points are set to zero.

Like Jeff Alton I have to be in the 13.5 range or I get the stall coming hard off idle. I can roll of idle ok just can't stab it. No stab = no fun

[Trog]

Originally Posted by dfink

Trog running at 14:1 at idle do you get any stumble if you just stab the throttle.

Only when cold. If I keep TOG at or above 13.5ms, she runs fine. Plus, I have my O2 closed-loop control disabled until which time the engine is warmed up (>60degC).

[Trog]

I haven't spent too much time with start-up enrichments, but here's where I am to date:

[dfink]

I think you are putting in way too much fuel on startup.

I would take out any warmup enrichments from 10 down and then have only maybe 2% at 10C = 50F add some back in if you go lean after the 20 second enrichments below.

I would definately set your fuel pump on time to 2 seconds.

se PW0 = 0
Set SE1 = 4
Set SE0 = 40

set ASE0 = 5
set ASE1 =0

These are not in correct order so just put as needed. If you add up all the enrichments you are dumping in a lot fuel for the first 20 seconds.

[Trog]

Originally Posted by dfink

I think you are putting in way too much fuel on startup.

I would take out any warmup enrichments from 10 down and then have only maybe 2% at 10C = 50F add some back in if you go lean after the 20 second enrichments below.

I would definately set your fuel pump on time to 2 seconds.

se PW0 = 0
Set SE1 = 4
Set SE0 = 40

set ASE0 = 5
set ASE1 =0

These are not in correct order so just put as needed. If you add up all the enrichments you are dumping in a lot fuel for the first 20 seconds.

It gets really cold up here (-15degC).. very dense air.. Trog need more fuel. Fuel is good!

[scarceller]

Originally Posted by Trog

It gets really cold up here (-15degC).. very dense air.. Trog need more fuel. Fuel is good!

Trog,

Whats your AFR at say 20F cold start? My stock setup is about 10.2AFR at these temps.

[TimT]

We try and run the around 13.5 on na and a tad richer on turbo engines, 12.8, though that range works well for both types. Also decel fuel is turned off.

No stab = no fun

this is probably because you are qoing very lean when you quickly crack the butterflies open. Does wintec have accel enrichment? or an accel pump feature?

Motec occasionally releases newsletters, some are new product info, others have some good tech info..some lambda guidlines

http://www.motec.com/filedownload.php/30JUNE2007.pdf?docid=2639

[Trog]

Originally Posted by scarceller

Trog,

Whats your AFR at say 20F cold start? My stock setup is about 10.2AFR at these temps.

Approx 10.5AFR

[scarceller]

Originally Posted by Trog

Approx 10.5AFR

Trog, this is what I found as well: I was surprised how rich you need to get the mixture at cold start. I posted a graph (prior post) of my cold start AFR vs CHT for my motronic setup, it may be helpful for you to see how the stock setup looks at cold start.

I also posted a (very simple) possible idea for how to easily get the RPMs higher at cold start. see earlier post

[dfink]

Originally Posted by TimT

We try and run the around 13.5 on na and a tad richer on turbo engines, 12.8, though that range works well for both types. Also decel fuel is turned off.



this is probably because you are qoing very lean when you quickly crack the butterflies open. Does wintec have accel enrichment? or an accel pump feature?

Motec occasionally releases newsletters, some are new product info, others have some good tech info..some lambda guidlines

http://www.motec.com/filedownload.php/30JUNE2007.pdf?docid=2639

Looks like I am about right then. At 13.5 I don't get the stall only when I go leaner. Wintec does have the acceleration enrichment but it is not quick enough to catch an off idle stab like a physical accelerator pump would. Mostly it just causes a delayed rich condition. I have it turned on but it is very low numbers mostly for cold operation.
There are many enrichments that can add up when starting they look small individually but when you add them all up you can be adding alot of extra fuel. I mostly have trouble on the first crank. It will usually die then run after the restart.
10.5 seems really rich for more than maybe the first second. You do need more fuel when cold but you shouldn't need a richer mixture. You just need enough additional fuel to make up for the denser air. I was also that rich but after taking out some of the various enrichment values the car runs much better on first startup. I do however think it could benefit from an air bleed to increase the idle. I don't know about your software but in mine under the idle settings there is a place to change the timing to adjust the idle speed. This can be set for different temperatures. I may try turning down my idle timing adjustment from 12 degrees to say 5 degrees. I would then need to open the idle screw a bit to increase the base idle to where I wanted it. I could then use the timing adjustment to increase the idle when cold. I am not sure how this would effect off idle operation but I think it is worth a try.
The really nice thing about the system is that if you try something totally different and if it doesn't work just reload the map that does work and instantly you are back running.

[scarceller]

Trog,

This is your thread and I feel I may be cluttering it. I can share details about how the stock Motronic system does is setup for Cold start as well as Part Throttle maps, PT Ignition is very important and for throttle response you do not want a flat linear map. Just ask if you want any details on the stock setup that you think could be useful to know.

Nice work on this install