A little AFR @ WOT info

Skalabala

Member +
My tuner gave me his AFRs
He is a well respected tuner and has a decade or so experience.

For non turbo it is 13-12.8
And turbo:
12.3 @ 0.5bar
11.5 @ 1bar
10.8-10.3 @ 1.5bar

Hope you can make something out of this Rev buddy :)
 

sx_turbo

Lifer
mixtures are far far to rich @ 1.5bar

no matter what boost you should be aiming for a afr of 11.5-12.2 on full boost
 

dark_knight

Member +
full boost, the definition of..

depends on what your definition of 'full boost' is sx_turbo.. for some it is 0.6bar.. for others it is 1.2bar.. surely you don't mean to tell me both these people should be reading the same AFR at their different boost thresholds..? :/
 

Skalabala

Member +
Well as I said in previous posts also.
Black smoke... and my tuner has a good reputation with great results always.
 

Dave.

Member +
I agree with sx_turbo, you'd want an AFR of way more than 10 on WOT with one of these...

I've always been under the impression you want to aim for an AFR of 12 or there abouts on WOT.

dark_knight: sx_turbo is still right - 0.6 or 1.2 doesn't matter.

Dave
 

dark_knight

Member +
boost & fueling

are you sure about that dave-gtturbo..? because if that's the case then what you are saying in essence is that fueling is EXACTLY the same whether you are running 0.6 or 1.2bar boost. is this what you are implying..?
 

Dave.

Member +
Hey,

Yes I am, re-read the comments - sx_turbo gave a fairly wide range of AFRs, within those will be fine @ 0.6. I don't want to get into the nitty gritty of extremely low or extremely high boost, that's not the point here, you're clouding the issue.

All I'm saying is, sx_turbo is absolutely correct @ 1.6 bar. I've always been under the impression you'd want way more than 10. somewhere within the AFRs he quoted would be safe, and would give more power than an AFR of 10.

I struggle to see the point in this thread, Skalabala's post doesn't have anything of real value as far as I can see.

Dave

EDIT: Worth nothing, nowhere did anyone say 'EXACTLY'.

are you sure about that dave-gtturbo..? because if that's the case then what you are saying in essence is that fueling is EXACTLY the same whether you are running 0.6 or 1.2bar boost. is this what you are implying..?
 
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dark_knight

Member +
differences

no need to get iffy over the subject dave-gttrubo, lighten up. i'm not trying to start a he-said-she-said debate. i asked whether that was the implication -- because people understand things differently. so saying one thing to one person may imply something else to another. anyway, a grammar lesson is besides the point here. you will agree with me that this is one of those topics where there is likely to be very many varied responses based on the fact that platforms/tunes/maps/age/conditions vary from engine to engine.. also bearing in mind that sensors don't always give multi-decimal accuracy, and even on the same engine, will give varied read-outs based on the single reason that no two 'testing' environments can be the same.. and as is also evident here, we are talking of 0.5 decimal differences..
so then, do we go with the 'safe' figures given above by Skalabala..?
 
How come every thread I come in to now adays is a debate? to much people copying and pasteing from other sites etc. am sx turbo on this one
 
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dark_knight

Member +
it's not always a debate starletgtturbo1, sometimes it's just ensuring that posts are accurate.. because information is only of any good if it's accurate. bad intel = big mistakes.. so when one member asks another to verify their information, it's not necessarily a debate now is it..? :)
 

Rev

Member +
My tuner gave me his AFRs
He is a well respected tuner and has a decade or so experience.

For non turbo it is 13-12.8
And turbo:
12.3 @ 0.5bar

11.5 @ 1bar
10.8-10.3 @ 1.5bar

Hope you can make something out of this Rev buddy :)



Thanks for that Skalabala makes alot of sense to me although I was looking at 11.3 at 1.3 bar , I will need to check my calculations with what you are saying.

Basically I have a K1 200v this is a small turbo pushing up to 1.27 x the ct9 air. When you have no more air to push one way you can get more power is to add fuel up to the point of optimum combustion. Which I think for the Starlet is about 11.3 afr for best rich torque at WOT.

There are other sides of the story to consider -

1 > If on boost depending on fuel , boost above a certain level will make det more likely. Kon on this site says don't go leaner than 12.4 on boost.
You may find different sources give various results for the boost that produces the quickest burn for a paricular fuel but your tuner is saying similarly with 12.3 at .5bar.

2 > Yes too rich causes less power because the most power produced is in the second stage of combustion and if you use too much oxygen in the first stage by using more fuel the second stage will not happen.

But
3 > Higher boost compresses the fuel which accelerates the combustion that is where the richer fuel comes in - ' Richening up the mixture results in a slower burn, moving the pressure peak later where there is more leverage, hence more torque. Also the pressure peak is lower at a later crank angle and the knock probability is reduced. The same effect can be achieved with an optimum power mixture and more ignition retard. '
 
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AdamB

Member +
AFR is irrespective of boost pressure. You can run a ct9 at 1 bar, then run a gt30 at 1 bar. But the fuel for 1 bar ct9 will not fuel 1 bar for a gt30. The gt30 flows more air at the same boost pressure.
 

Skalabala

Member +
Come now people we are all friends here :)
Just thought I'd share something with you.
And as I said it has been working for him for a long time.
Might be the altitude playing a role here?
 

dark_knight

Member +
but AdamB, please correct me if i'm wrong, pressure is pressure.. whether being pumped by a ct9 or any other turb -- unless you are suggesting that 1bar on a ct9 (pressure-wise only) is different from 1bar on a different-spec'd turb..?

what i may argue on though is charge temperature.. because again, all factors held constant, your post may be implying that fueling at 1bar on a ct9-powered engine will be different than 1bar on a gt30-powered engine basing this on charge pressure only (presumed to be at 1bar). we must remember the ECU fuels not just based on pressure, but intake charge temp as well. true or not..?
 

AdamB

Member +
Yes true it will depend on temperature and density, but if all turbo's flowed the same CFM at the same boost we wouldn't make anymore power upgrading turbo's will we :D
Running a well setup ct9 at 1 bar fuel spot on, if you then change to a gt30 for example, your map won't fuel the extra CFM the gt30 puts out, therefore running lean.
 

dark_knight

Member +
^^ i concur. i was trying to rid the blanket notion that we can all have the same AFRs albeit all our different setups..
 

spuddy

Ulster Area Rep.
Come now people we are all friends here :)
Just thought I'd share something with you.
And as I said it has been working for him for a long time.
Might be the altitude playing a role here?

Could be many things climate related, your in a warmer part of the world so maybe det is an issue with leaner mixtures.

How much power is there to be had leaning out from say 10.0-11.0 up to 11.8???

Personally mines runs 5.0 but thats a different debate I guess.
 

Skalabala

Member +
I am going to him tomorrow, I will ask him for print outs with logs.
Also eager to see how this works :D
Spuddy buddy you running meth?
 
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