Sale ends todayGet 30% off any course (excluding packages)

Ends in --- --- ---

Tuning with AFR or lambda?

General Tuning Discussion

Forum Posts



Tech Articles

Discuss all things tuning in this section. News, products, problems and results. 

= Resolved threads


Hopefully this one can get an answer finally,

I'm thinking about getting the new Holley Terminator X for my 5.3 single turbo build. It seems right now the only way to tune it is in AFR not lambda.

Can I have the windscreen mouted innovative wideband reading lambda and tune from this? Or should I learn how to tune in AFR now even though i've got Lambda down?

I'm not too filmier with Holley systems, but it seems odd you can't change it to LAMBDA. If you have an accurate readout in your cabin and can log it, you can use whatever you prefer (in this case Lambda). If you can only log AFR through the ECU, then I would use that and just take the time to adjust to the different readout.

Well it's their basic of basic systems, 1,000 USD and you get the standalone with 4 I/O, bosch 4.9, 3.5" LCD, and Engine harness for that price for the LS engines. I just can't pass that up. The only thing that sucks is I just dont know how to tune in AFR compared to Lambda because as you're aware too, lambda is so easy to know right away how much to add and how much to take away. If i'm reading say 14.8 and I need 13.8 (for gasoline but i'll be on e85), I don't know how much in percentage i need to add to get down to that 13.8 from 14.8. Only way i know is to take that 14.8 and divide it by my target of 13.8 and get 1.072. So basically that's 7 percent, but i'd have to do that for every single cell, yea no thank you lol!

I need to call Holley and see if they can update their terminator X software and add the option of tuning in lambda because I know the bosch 4.9 can read in lambda so.

Anyone else?

Switching from AFR to Lambda, or Lambda to AFR isn't too bad if you ask me. I think it helps to print out a little reference chart, for instance 0.70 lambda is about 10.3 AFR Gasoline, 0.80 lambda is about 11.7 AFR Gasoline, 0.90 lambda is about 13.2 AFR Gasoline. A very quick & dirty rule of thumb is about 1.0 AFR (gasoline) is about 10% fuel difference, for instance if the datalog shows 13.0 AFR and your target was 12.0 AFR adding 10% to the map should get close. Depending on whether you're adding or removing fuel, you may want to intentionally add a little more (or remove a little less) to intentionally keep things a little rich rather than a little lean.

Ahh ok, yea. I'm assuming on E85 it may be a 15% difference then with 1.0 afr difference? The other thing is, i'm not sure if the bosch 4.9 can read down that low as for some of my targets i'm at around 7.8 target to start at about 7psi of boost (150kpa). That's just a starting point then i'd see if it would like to have more fuel from there. Definitely not less (about .80 lambda to start).

Andre, any thoughts?

As far as I know, the Bosch LSU 4.9 reads down to Lambda 0.65, so you're not likely to find its limit with E85 .... on another note, in most cases you don't even need to run as rich as with pure gasoline.

Slowcivic, your wideband reads in lambda and then multiplies it by whatever fuel/afr you define as stoichiomentric. If you're worried about 7.8:1 AFR with E85, that's only ~.8 lambda so you may be confusing yourself by flip flopping between an AFR target and a lambda target already.

We usually reply within 12hrs (often sooner)

Need Help?

Need help choosing a course?

Experiencing website difficulties?

Or need to contact us for any other reason?