After reading a post from someone who’s dyno guy seemed to have no idea how to tune a turbo i thought it best that i should understand that he is fuelling the bike right, rather than me just putting my faith in someone who might not know how to tune a turbo (but won’t admit it) So..........
Could someone perhaps explain to me what the air/Fuel ratio should be doing throughout rev range please? My bike will be using Lorcans 810cc, rc310, T25, intercooler map as my specs are the same apart from the big valves and cams. So boost goes to 32 psi, although i will probably set max boost to 15Psi for the moment (approx. 50% throttle on the Power commander map) but knowing what it should be beyond that would be useful for future reference.
I understand that at idle the A/F ratio should be between 14 – 18:1 and at full boost/max torque the A/F Ratio should be ideally between 11 – 12:1, but what about inbetween? I’m guessing that pre boost A/F should be around stoich’ 14.7:1 ? Then just before boost comes in what value ideally should it change to? And does it then gradually increase to between 11 - 12:1?
Ta,
Andy.
Air/Fuel Ratio thru' the Rev Range (up to 15PSi)
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KWAK 750 TURBO
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- Posts: 173
- Joined: Mon Aug 11, 2003 12:01 pm
- Location: Warrington, Cheshire
Re: Air/Fuel Ratio thru' the Rev Range (up to 15PSi)
Hi
When I posted this Dyno run Lorc said the higher HP AF line was a bit too weak for 150 hp.
It did not make more Hp cos it was weaker more that I turned the boost up to 15 psi from 10 psi. At some point in the dyno runs I also turned the pot down on the cut wire cos at the time I was not running the PC just upped the fuel pressure and fitted an adjustable pot to trim the fueling. That part worked a treat. So the increase fueling is the STD ECU's map set by BIG K. I have found that the idle mixture should be 13.5-14, then richen up a little to pull away or it stutters, say about 12, then weaken off for normal riding say 13-14. As the boost kicks in you will need to adjust to match how much boost/hp you are getting on your bike.
Tack1000
When I posted this Dyno run Lorc said the higher HP AF line was a bit too weak for 150 hp.
It did not make more Hp cos it was weaker more that I turned the boost up to 15 psi from 10 psi. At some point in the dyno runs I also turned the pot down on the cut wire cos at the time I was not running the PC just upped the fuel pressure and fitted an adjustable pot to trim the fueling. That part worked a treat. So the increase fueling is the STD ECU's map set by BIG K. I have found that the idle mixture should be 13.5-14, then richen up a little to pull away or it stutters, say about 12, then weaken off for normal riding say 13-14. As the boost kicks in you will need to adjust to match how much boost/hp you are getting on your bike.
Tack1000
Last edited by tack1000 on Sat Aug 09, 2014 4:19 pm, edited 2 times in total.
Re: Air/Fuel Ratio thru' the Rev Range (up to 15PSi)
Hi
So if you take the blue line for off boost and then slide down to the red line as the boost comes in and match the red line from about 85mph on the graph then keep at 11.5 -11 not like the red like as it drops to 10.5 which is a bit rich now. That's about it. From what Lorc has said.
That engine was a 738cc STD pistons, Blue printed engine, 1100 TB's STD injectors, variable fuel pressure reg, Race mode with pot, STD headers STD exhaust housing with a KKK other housing which was only a little bigger than STD.
10 psi boost =129 rwhp 15 psi boost = 154 rwhp
I NEVER LEFT THE BIKES SIDE ONCE. I had to guide the dyno operator but he was a real nice guy who was ready to talk and share ideas and thoughts. I did the adjustment he ran the dyno.
Tack1000
So if you take the blue line for off boost and then slide down to the red line as the boost comes in and match the red line from about 85mph on the graph then keep at 11.5 -11 not like the red like as it drops to 10.5 which is a bit rich now. That's about it. From what Lorc has said.
That engine was a 738cc STD pistons, Blue printed engine, 1100 TB's STD injectors, variable fuel pressure reg, Race mode with pot, STD headers STD exhaust housing with a KKK other housing which was only a little bigger than STD.
10 psi boost =129 rwhp 15 psi boost = 154 rwhp
I NEVER LEFT THE BIKES SIDE ONCE. I had to guide the dyno operator but he was a real nice guy who was ready to talk and share ideas and thoughts. I did the adjustment he ran the dyno.
Tack1000
Re: Air/Fuel Ratio thru' the Rev Range (up to 15PSi)
Hi
Just to make sure you know, That is with NO PC. That fuel line is created by the map in the ECU set by Kawasaki. As you can see the line does not change it's shape much, just it's position as I turn the pot.
Tack1000
Just to make sure you know, That is with NO PC. That fuel line is created by the map in the ECU set by Kawasaki. As you can see the line does not change it's shape much, just it's position as I turn the pot.
Tack1000
Re: Air/Fuel Ratio thru' the Rev Range (up to 15PSi)
Jeff - what do you mean by blue printed engine
Re: Air/Fuel Ratio thru' the Rev Range (up to 15PSi)
Hi
It's an old term, I think it's when drawings were made for the shop floor they were blue with white lines. (copies or bromides) So if an engine was "blue printed" it was meant the engine was as the designer meant it to be not how production could get it within the day to day machining tolerances.
Like casting flaws and small miss matches between parts. All these small production errors are removed to get the best from the engine without a true tune up. Matching rod and piston weights, that sort of thing
Gas flowing and porting a head is not blue printing, just matching the valve seat to the ali casting is.
Tack1000
It's an old term, I think it's when drawings were made for the shop floor they were blue with white lines. (copies or bromides) So if an engine was "blue printed" it was meant the engine was as the designer meant it to be not how production could get it within the day to day machining tolerances.
Like casting flaws and small miss matches between parts. All these small production errors are removed to get the best from the engine without a true tune up. Matching rod and piston weights, that sort of thing
Gas flowing and porting a head is not blue printing, just matching the valve seat to the ali casting is.
Tack1000
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KWAK 750 TURBO
- Member
- Posts: 173
- Joined: Mon Aug 11, 2003 12:01 pm
- Location: Warrington, Cheshire
Re: Air/Fuel Ratio thru' the Rev Range (up to 15PSi)
Cheers jeff, thats really helpful. Now i've got some idea of what should be happening through the rev range i'll be a lot happier at the Dyno 
Re: Air/Fuel Ratio thru' the Rev Range (up to 15PSi)
That's a great summary Jeff - Tupz I hope you are reading this!
Kawasaki put a good curve into the bike for stock boost, but as you turn the boost up it tends to lean out, which is not what you want. The idle and off boost ratio isn't really important, you can give it whatever it needs to run smoothly (but it will probably end up like Jeff has described). The important thing is that the engine gets enough fuel around peak torque and above to avoid detonation.
It's the PC's ability to alter the shape of the a/f curve as much as you want that makes it a superior method to resistors etc.
Kawasaki put a good curve into the bike for stock boost, but as you turn the boost up it tends to lean out, which is not what you want. The idle and off boost ratio isn't really important, you can give it whatever it needs to run smoothly (but it will probably end up like Jeff has described). The important thing is that the engine gets enough fuel around peak torque and above to avoid detonation.
It's the PC's ability to alter the shape of the a/f curve as much as you want that makes it a superior method to resistors etc.
First to 200mph (2006) and still the fastest (211mph)
Quickest turbo-only 8.69 @ 162mph
Quickest turbo-only 8.69 @ 162mph
Re: Air/Fuel Ratio thru' the Rev Range (up to 15PSi)
Reading it now.
Re: Air/Fuel Ratio thru' the Rev Range (up to 15PSi)
Have been adjusting AF using the stated variable resister setup - so thought I would wake this old and v useful post.tack1000 wrote:Hi
When I posted this Dyno run Lorc said the higher HP AF line was a bit too weak for 150 hp.
It did not make more Hp cos it was weaker more that I turned the boost up to 15 psi from 10 psi. At some point in the dyno runs I also turned the pot down on the cut wire cos at the time I was not running the PC just upped the fuel pressure and fitted an adjustable pot to trim the fueling. That part worked a treat. So the increase fueling is the STD ECU's map set by BIG K. I have found that the idle mixture should be 13.5-14, then richen up a little to pull away or it stutters, say about 12, then weaken off for normal riding say 13-14. As the boost kicks in you will need to adjust to match how much boost/hp you are getting on your bike.
Tack1000
Was getting pretty high numbers on and off boost, so went through a series of richen, ride,check guage through rev range - to a point where I've run out of pot adjustement....
I thought at that point it would be so rich it would run like a dog, but it doesen't!
This is where I'm at.
Off boost burbling around up to 80ish - guage flickers between 15-16
WOT and boosting hard - plummets to 11-12
Sitting at speeds between around 100 - 150 reads a nice 11-12 also
Lower and off boost AF seems too high still?
If so may turn up the fuel pressure, but not sure thats going to help off boost?
I can't feel or hear any detonation and its really smooth with loads of torque off boost - but do you reckon 15-16 is too lean off boost?
Re: Air/Fuel Ratio thru' the Rev Range (up to 15PSi)
Hello
Glad your getting to use it and have time to play.
With no boost and no load it pretty much a mute point what the gauge says, it's really only what it does as soon as you start to load up the engine and boost starts to be made. If it drops to 11-12 then that's safe and good. Watching the gauge whilst rolling on full throttle from low RPM to high RPM in top is very hard.
That's where the data logging comes in which the unit does have but at the moment I did not wire a remote switch in to turn it on and off. It's easy and I know you can tackle that one with the right info.
If you still have that little Acer, then that would be perfect to check what's going on, you could almost stick it down your jacket or pop it in a ruck sack for when you stop. Then just plug it in and have a look at that run.
Glad your getting to use it and have time to play.
With no boost and no load it pretty much a mute point what the gauge says, it's really only what it does as soon as you start to load up the engine and boost starts to be made. If it drops to 11-12 then that's safe and good. Watching the gauge whilst rolling on full throttle from low RPM to high RPM in top is very hard.
That's where the data logging comes in which the unit does have but at the moment I did not wire a remote switch in to turn it on and off. It's easy and I know you can tackle that one with the right info.
If you still have that little Acer, then that would be perfect to check what's going on, you could almost stick it down your jacket or pop it in a ruck sack for when you stop. Then just plug it in and have a look at that run.
Re: Air/Fuel Ratio thru' the Rev Range (up to 15PSi)
Super cool - I'm safe when I'm hitting it hard, thats what I wanted to hear. Not that it seems that hard on the girl at 140+mph - but the getting there is reather tasty
No messing with the fuel pressure is also good news
Jeff, watching the guage is fxxing hard like you say, but there is a nice copless dual c/way where I was doing this today and can deffo say it drops like a stone to the 11-12 range now which is good news
I have still got that acer, so it might get used for something useful for the 1st time
No messing with the fuel pressure is also good news
Jeff, watching the guage is fxxing hard like you say, but there is a nice copless dual c/way where I was doing this today and can deffo say it drops like a stone to the 11-12 range now which is good news
I have still got that acer, so it might get used for something useful for the 1st time
Re: Air/Fuel Ratio thru' the Rev Range (up to 15PSi)
Idle and cruise can be anywhere from 14 to 18:1. You don't want it rich there as this is where the engine spends the majority of it's life and running too rich will cause bore wash (the fuel washing the oil from the bores).
Once you get to really high sustained boost (30psi+) it's all about keeping the motor together, so although it might make more power at 13:1 it won't do it for very long. We run rich and safe 10-11:1 to help keep everything cool. Man
Once you get to really high sustained boost (30psi+) it's all about keeping the motor together, so although it might make more power at 13:1 it won't do it for very long. We run rich and safe 10-11:1 to help keep everything cool. Man
First to 200mph (2006) and still the fastest (211mph)
Quickest turbo-only 8.69 @ 162mph
Quickest turbo-only 8.69 @ 162mph
Re: Air/Fuel Ratio thru' the Rev Range (up to 15PSi)
Thats the other dumb arsed q I had regarding off boost numbers, if anything its a bit rich maybe at idle 12-1, might try and turn it down a bit but its not bogging down or running rough so far and cruise does lean off.
16psi on this GT17 feels like a missle - not sure I would ever have the bottle for 30psi
Thanks for the explanations gents
16psi on this GT17 feels like a missle - not sure I would ever have the bottle for 30psi
Thanks for the explanations gents
Re: Air/Fuel Ratio thru' the Rev Range (up to 15PSi)
How are you planing on turning it down a bit? The TPS I hope. Its a real tricky one on yours AFAIR, well touchy.Chris G wrote:Thats the other dumb arsed q I had regarding off boost numbers, if anything its a bit rich maybe at idle 12-1, might try and turn it down a bit but its not bogging down or running rough so far and cruise does lean off.
16psi on this GT17 feels like a missle - not sure I would ever have the bottle for 30psi
Thanks for the explanations gents
What fuel are you using