Haltech Let's talk staging...
08-09-07, 11:58 AM
#1
Let's talk staging...
I'd like a little cross-sampling of how people are setting up their staging.
Please include your ECU type, injector sizes, staging bar, and duration/rpm.
I'm currently trying to mod my 750/1000cc E6X map to accomidate 1600's as oppose to 1000's - my 750's are still in place.
Currently, my staging bar is set to 12 and on the 11 bar I'm running around 5.8ms at 3K rpm which is a high 11, low 12 AFR at that point....my current 12 bar is 4.164ms at 3K rpm which drowns the engine while transitioning.
I'm thinking I need around 3ms to get me up near the 10's so I can tell wassup (lousy AEM wideband only reads to 10.0:1) but if that is still to much, or if its too little I'd like to know.
Just starting my positive pressure tuning now and I'd like to try to get a smooth transtion before moving forward.
Any input is appreciated
Please include your ECU type, injector sizes, staging bar, and duration/rpm.
I'm currently trying to mod my 750/1000cc E6X map to accomidate 1600's as oppose to 1000's - my 750's are still in place.
Currently, my staging bar is set to 12 and on the 11 bar I'm running around 5.8ms at 3K rpm which is a high 11, low 12 AFR at that point....my current 12 bar is 4.164ms at 3K rpm which drowns the engine while transitioning.
I'm thinking I need around 3ms to get me up near the 10's so I can tell wassup (lousy AEM wideband only reads to 10.0:1) but if that is still to much, or if its too little I'd like to know.
Just starting my positive pressure tuning now and I'd like to try to get a smooth transtion before moving forward.
Any input is appreciated
08-09-07, 04:44 PM
#2
Tuning the staging bars is the same as tuning any other load site. You need to hold the engine in the load site long enough to get a good reading and to ensure that the throttle pump is not influencing the mixture. My advice is to not get caught up in the on time numbers and the math of what "should" work. Unless the on time numbers are way off what they should be, indicating a problem, or they're indicating a duty cycle issue they're just a number. Give the engine what it wants. Not what you think it should want.
Ideally you'll do this on a dyno. It's much easier and exact than trying to do it on the road. However if you must road tune here are some tips.
-Roll up to the load cell. Don't stab the throttle causing the throttle pump to actuate.
-A big, long hill helps when working in these bars. It loads the engine more and makes it easier to consistently load the cells near and just above 0 psi.
-Use the brakes or the e-brake to load the car if there are no hills available. Problem is you can only use them in very short spans and need to let the brakes cool between applications. You can roast a set of cheap pads doing this very quickly but it does work.
The rotary has a relatively flat VE curve above about 3500 rpm. What that means is that the injector on time will be very similar for a given load/rpm between 4k and 8k. This is a broad generalization and port configuration and other factors play into this but for stock, street, and mild bridge ports it's a decent rule of thumb. Slightly more fuel will be needed near peak torque (peak VE) and the on time will taper off slightly past peak torque as the RPM continue to rise. So what that means in that for a given load/rpm what works at 4k will be close to what you need at 6k and 8k.
I say close because these numbers will get you up and running well but it will not be your final tune. I'll usually start a car, get it idling, throw a map at it that I know will be rich in all areas, then drive it around and work out the map up to about 4k and just past the transition to the secondarys. At this point I can take what I know at 4k and plug it in all the way up to 8k+ and know that I'm pretty close. At that point you start dipping a little higher in the rev and load ranges to explore what you have. You don't make one banzai charge at full load to 8k right away.
Helpful?
Ideally you'll do this on a dyno. It's much easier and exact than trying to do it on the road. However if you must road tune here are some tips.
-Roll up to the load cell. Don't stab the throttle causing the throttle pump to actuate.
-A big, long hill helps when working in these bars. It loads the engine more and makes it easier to consistently load the cells near and just above 0 psi.
-Use the brakes or the e-brake to load the car if there are no hills available. Problem is you can only use them in very short spans and need to let the brakes cool between applications. You can roast a set of cheap pads doing this very quickly but it does work.
The rotary has a relatively flat VE curve above about 3500 rpm. What that means is that the injector on time will be very similar for a given load/rpm between 4k and 8k. This is a broad generalization and port configuration and other factors play into this but for stock, street, and mild bridge ports it's a decent rule of thumb. Slightly more fuel will be needed near peak torque (peak VE) and the on time will taper off slightly past peak torque as the RPM continue to rise. So what that means in that for a given load/rpm what works at 4k will be close to what you need at 6k and 8k.
I say close because these numbers will get you up and running well but it will not be your final tune. I'll usually start a car, get it idling, throw a map at it that I know will be rich in all areas, then drive it around and work out the map up to about 4k and just past the transition to the secondarys. At this point I can take what I know at 4k and plug it in all the way up to 8k+ and know that I'm pretty close. At that point you start dipping a little higher in the rev and load ranges to explore what you have. You don't make one banzai charge at full load to 8k right away.
Helpful?
08-09-07, 05:06 PM
#3
Very helpful, thank you.
I'm relatively aware of the similairties in fuel requirements between 4K and 8K, which is why I'm trying to get everything below there well sorted, similar to your method that you mentioned.
My main concern is what kind of duration I'll be looking at for a 1600cc injector....simply because I lost an engine after 300km's just a month ago due to unknown reasons. May have been seals (atkins), may have been improper groove clearance - but one other (very very low possibility) would be overly rich detonation (which I'm honestly still trying to understand, but BDC thinks was the cause) and because of that reason alone, I'm scared to just start trying to tune 1-2psi with the map configured for 1000cc secondaries.
I figured at the same time I could get some info on how others are setting up their staging and compare it to mine. Edit: I also realize that the math isn't always an absolute becuase you have to figure airflow/atomization in also, especially with 1600's.
I realize I'm not extremely loading the engine at these rev's and pressures, and my timing is backed off to be very conservative, but nonetheless I want to take it slowly and carefully as possible.
edit: As well - I always try to keep the load constant on the cells as to not activate the throttle pump....a very good tip sir
But you gave me some very good tips, thank you.......
I'm relatively aware of the similairties in fuel requirements between 4K and 8K, which is why I'm trying to get everything below there well sorted, similar to your method that you mentioned.
My main concern is what kind of duration I'll be looking at for a 1600cc injector....simply because I lost an engine after 300km's just a month ago due to unknown reasons. May have been seals (atkins), may have been improper groove clearance - but one other (very very low possibility) would be overly rich detonation (which I'm honestly still trying to understand, but BDC thinks was the cause) and because of that reason alone, I'm scared to just start trying to tune 1-2psi with the map configured for 1000cc secondaries.
I figured at the same time I could get some info on how others are setting up their staging and compare it to mine. Edit: I also realize that the math isn't always an absolute becuase you have to figure airflow/atomization in also, especially with 1600's.
I realize I'm not extremely loading the engine at these rev's and pressures, and my timing is backed off to be very conservative, but nonetheless I want to take it slowly and carefully as possible.
edit: As well - I always try to keep the load constant on the cells as to not activate the throttle pump....a very good tip sir
But you gave me some very good tips, thank you.......
08-09-07, 08:32 PM
#4
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A general rule of thumb (but not always the case), is if you have 850 primaries, and 1600 secondaries, the stagging bar will be half the hight of the last bar before the secondaries kick in, on stock and street ported engines this usually works for me in those cases.
In your case, since the primaries are 750s, and secondaries will be 1600, you're probably looking at a slightly higher number on the first stagged bar, but only very slightly.
I know some people will probably disagree with that statement, but it has proven a good starting reference for me to get a car going initially.
In your case, since the primaries are 750s, and secondaries will be 1600, you're probably looking at a slightly higher number on the first stagged bar, but only very slightly.
I know some people will probably disagree with that statement, but it has proven a good starting reference for me to get a car going initially.
08-09-07, 10:22 PM
#5
Lives on the Forum
My advice is to not get caught up in the on time numbers and the math of what "should" work. Unless the on time numbers are way off what they should be, indicating a problem, or they're indicating a duty cycle issue they're just a number. Give the engine what it wants. Not what you think it should want.
Unless you got some funky resonance happening in the engine, doing the quick math gets you pretty close.
For example, if you're running identical size injectors for all 4, then your post-stage bar will be approximately 1/2 the pre-stage bar.
I adjust the post-stage bar a little more than half just to be safe and fine tune from there.
Since you're going with a 750 / 1600 combo, the 1600's are approximately 2x the size of your primaries, so your post-stage bar will be about 1/3rd the pre-stage bar.
Adjust the bar slightly higher than 1/3rd just to be safe.
This is where the "disadvantage" of the Haltech staging (RPM dependent only) might actually be of use...
You can play with the ratios at low, low RPM's to see what kinda results you get.
Once you get an idea of how the pre- and post- bar heights should be, the rest of the RPM's should be pretty easy to figure out.
-Ted
08-09-07, 10:28 PM
#6
I tend to disagree...
Unless you got some funky resonance happening in the engine, doing the quick math gets you pretty close.
For example, if you're running identical size injectors for all 4, then your post-stage bar will be approximately 1/2 the pre-stage bar.
I adjust the post-stage bar a little more than half just to be safe and fine tune from there.
Since you're going with a 750 / 1600 combo, the 1600's are approximately 2x the size of your primaries, so your post-stage bar will be about 1/3rd the pre-stage bar.
Adjust the bar slightly higher than 1/3rd just to be safe.
This is where the "disadvantage" of the Haltech staging (RPM dependent only) might actually be of use...
You can play with the ratios at low, low RPM's to see what kinda results you get.
Once you get an idea of how the pre- and post- bar heights should be, the rest of the RPM's should be pretty easy to figure out.
-Ted
Unless you got some funky resonance happening in the engine, doing the quick math gets you pretty close.
For example, if you're running identical size injectors for all 4, then your post-stage bar will be approximately 1/2 the pre-stage bar.
I adjust the post-stage bar a little more than half just to be safe and fine tune from there.
Since you're going with a 750 / 1600 combo, the 1600's are approximately 2x the size of your primaries, so your post-stage bar will be about 1/3rd the pre-stage bar.
Adjust the bar slightly higher than 1/3rd just to be safe.
This is where the "disadvantage" of the Haltech staging (RPM dependent only) might actually be of use...
You can play with the ratios at low, low RPM's to see what kinda results you get.
Once you get an idea of how the pre- and post- bar heights should be, the rest of the RPM's should be pretty easy to figure out.
-Ted
True enough and I totally agree. Doing the math and adding just a little on top for safety is where I begin. Then tune it out. What I mean is that if you start with 400cc primary and 400cc secondary and the transition bar is not exactly 50% of the on time as the last pre-transition bar the world is not lost. Now if it's 90% or 20% then you probably have an issue.
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08-10-07, 02:22 PM
#10
Isn't the bar whereever you select it on the pressure scale?
As in, if my staging bar number is set to 11 and I count the number of bars from left to right on the pressure scale on the fuel map....11 is where the stage occurs, no? Because I can build that type of pressure (11kpa IIRC) at low RPM and still turn on the secondaries (at least, according to the wideband)
But what you're saying is that the staging bar is to be counted on the RPM side of the map? Meaning setting the bar to 11 will only make the secondary injectors come on beyond 5000rpm?
we're all human...
08-10-07, 10:40 PM
#13
tom port.. AKA streetport
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ive always been nervous since building boost early in the RPMS. persay: 5TH gear @2500 or 3000 RPM's and you got WOT. your gonna build boost. this is how i popped my 6 port turbo. primaries just werent big enough.
08-10-07, 10:50 PM
#14
Lives on the Forum
Just realized this......
Isn't the bar whereever you select it on the pressure scale?
As in, if my staging bar number is set to 11 and I count the number of bars from left to right on the pressure scale on the fuel map....11 is where the stage occurs, no? Because I can build that type of pressure (11kpa IIRC) at low RPM and still turn on the secondaries (at least, according to the wideband)
But what you're saying is that the staging bar is to be counted on the RPM side of the map? Meaning setting the bar to 11 will only make the secondary injectors come on beyond 5000rpm?
Isn't the bar whereever you select it on the pressure scale?
As in, if my staging bar number is set to 11 and I count the number of bars from left to right on the pressure scale on the fuel map....11 is where the stage occurs, no? Because I can build that type of pressure (11kpa IIRC) at low RPM and still turn on the secondaries (at least, according to the wideband)
But what you're saying is that the staging bar is to be counted on the RPM side of the map? Meaning setting the bar to 11 will only make the secondary injectors come on beyond 5000rpm?
I got all confused with all the terminology.
The staging bar is MAP (sensor) / pressure dependent!
*NOT* RPM dependent.
Doh!
-Ted
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