Fuel map target lambda - individual targets?

s300 and SManager software questions & answers
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itsahonda
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Joined: Sun Mar 21, 2021 12:29 pm

Fuel map target lambda - individual targets?

Post by itsahonda »

Is there a way to change the target lambda of an individual cell on the fuel map?

I’m trying to set up lean afr for cruising, and the issue is that with my setup I have very low vacuum with as low as 25% throttle when cruising/light accel during highway driving. Near wot, essentially.

So I wanted to tune for sub-4000rpm range specifically. That way it has lean for cruise specifically, and isn’t vacuum based.

Since the vtec and non vtec maps use the same vacuum target lambda settings, i can’t make them separate.
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Spunkster
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Re: Fuel map target lambda - individual targets?

Post by Spunkster »

No you cannot change a single cell like that.
itsahonda
Posts: 5
Joined: Sun Mar 21, 2021 12:29 pm

Re: Fuel map target lambda - individual targets?

Post by itsahonda »

That is honestly very disappointing. I’d make the argument that the ability to have finer control over the target lambda fuel tables would be not only a good addition, but something that should already be in it.

I’ll have to find another way.

Maybe a 5th gear compensation to lean it out for cruising?
DaX
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Joined: Tue Mar 18, 2003 3:48 pm

Re: Fuel map target lambda - individual targets?

Post by DaX »

itsahonda wrote: Mon Mar 29, 2021 5:43 pm That is honestly very disappointing. I’d make the argument that the ability to have finer control over the target lambda fuel tables would be not only a good addition, but something that should already be in it.

I’ll have to find another way.

Maybe a 5th gear compensation to lean it out for cruising?
I agree - I do wish there was more than "low / med / high" load settings for target lambda values.
spAdam
Posts: 57
Joined: Sat May 03, 2014 5:34 pm

Re: Fuel map target lambda - individual targets?

Post by spAdam »

Assuming this is an issue because you are using closed loop by lambda target - I get around it by using the TPS tables to disable closed loop at idle:
TPS Closed loop
TPS Closed loop
Screenshot 2021-03-30 152200.png (10.98 KiB) Viewed 1055 times
then tuning my idle to lambda 1.0. This lets my target my lean cruise without it trimming my idle lean. Note the tight breakpoints 1250-1265; that's as close as the bit math in the cal would let me get to having close loop 'switch on' above 1250.

It's a hack, but it gets the job done.
itsahonda
Posts: 5
Joined: Sun Mar 21, 2021 12:29 pm

Re: Fuel map target lambda - individual targets?

Post by itsahonda »

To make sure I understand what you’re saying:

Setup idle to idle in open loop, and then setup the normal closed loop fuel tables to whatever leaner-cruise settings I want, etc - so it’s like adding another “section” the the fuel tables below a certain rpm...

Not bad man, thanks
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