Anti-lag...staging spool injection strategy.

DIESEL_POWER said:
Chris, with the boost advance your seeing, VS a stock tune, like your first post, what was the RPM, seems to me that CFM plays big part here.

Are you just stabing the throttle to see these #'s? or are you at a steady rpm?

in other words @ 3000 rpm stock tune what is the boost?

" " modded tune what is the boost?
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3000 rpm regular smarty tune or single event stand alone 7-9 psi.

3000 rpm with the modified injection strategy 50 lbs boost. Free. Rev absolutely no load.

Your right though rpms make a big difference. Took it up to 4k and the turbos were screaming. Like my guys were backing out of the shop loud.
 
Joesixpack said:
On the heat issue with the head, it makes sense. Staging with a converter your rpm's are fairly low....water pump output less. Limiting the time staging can't hurt.

Thing is, I've put more heat to this head than ever, pulled some crazy stuff with timing, buried the 2000 pyro several times.....no dropped seats as of yet.



I remember you posting on your runs you max out at 1250 or less, yet have had multiple seat issues? I'm still in the camp that cylinder heat that drops seats. Egt's might not be the best indicator.
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The 1250 you are talking about is either from my 02, or from a post I made to TY, talking about running no programing and 60psi of boost. That was to help him trouble shoot his problem.

When I have dropped valve seats you can bet the EGT's were above 1250, though never above 1600. The problem however is not really the EGT's or the cylinder temps. Its the water not keeping the head cool enough around the valve seat. This is not a new problem. I can remember having the same problem on Pontiac engines back in the 80's. It just that the Cummins head design makes it harder to overcome the heat issue.

I have never dropped a valve seat (or had one come loose), while building boost. Even though the EGT's are maybe 2000+ the total BTU's that are produced are small compared to what happens during a pass. If however you can keep the EGT's down during staging you are at least not pre-heating the head (and the water) as much. I don't care how much heat you apply to the surface of head, if you can get rid of the head, then there won't be a problem. It's when the head gets hot and expands around the seat, it never shrinks all the way back. It's a progressive thing, until the seat drops. Notice that most seats drop on start up?

Sorry for the derail. I think you are on the right track for initially building boost.

Paul
 
SMOKIN-U said:
so are you basically making it have three injection events like a 600 motor but have the last comein late then when you reach your preset boost of say 20# and th eturbo is lit well having it go back to 1 event like a 12 valve? If so can you program to add the injection events back in say when its coming down in rpm so when the sled hits and its pulling down the rpm the other events would kick in and help keep the charger from snuffing out at the end of the track? Not for sure if i worded that correctly or not mainly just wondering if that is even possible or if there would be a benifit there?
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That is the exact idea. Modified for staging. Back to one event under load. Never thought about the heavy end. I'm not sure about that. The positive displacement nature of the engine still suggests that if you get below a certain rpm your stuffing the charger. Heat is usually not the problem there.
 
true but never know it may help. heck if you are getting that kind of boost doing that at a free rev why wouldnt it work at a lower rpm? i suppose it would be worth a try if you have the ability to change the paramiters. it would be interesting to see what would happen for sure. who knows that may give the cr the ability to run massive turbos and make a lot power plus keep it lit at the other end of the track unlike some 12 valves wth having that extra event there.
 
I definetly see what your saying and worth experimenting with, but for hanging on to a large charger rpms rpms rpms lol......
 
Joesixpack said:
3000 rpm regular smarty tune or single event stand alone 7-9 psi.

3000 rpm with the modified injection strategy 50 lbs boost. Free. Rev absolutely no load.

Your right though rpms make a big difference. Took it up to 4k and the turbos were screaming. Like my guys were backing out of the shop loud.
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so this is stabbing the throttle or steady RPM?
 
DIESEL_POWER said:
so this is stabbing the throttle or steady RPM?
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Steady rpm. Not stabing the throttle. Simply raising the rpms up to 3k.

This could be difficult to duplicate with efi live. As it was a true split main as in half the fuel come in late. Not just a post injection quantity for emissions.
 
Joesixpack said:
Never thought about the heavy end. I'm not sure about that. The positive displacement nature of the engine still suggests that if you get below a certain rpm your stuffing the charger. Heat is usually not the problem there.
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Agreed. Not sure there's much to be had when you have all the heat you need and the mass flow is simply dropping off enough to hit the surge line.
 
Joesixpack said:
Steady rpm. Not stabing the throttle. Simply raising the rpms up to 3k.

This could be difficult to duplicate with efi live. As it was a true split main as in half the fuel come in late. Not just a post injection quantity for emissions.
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Getting the Post to work can be troubling on a Dmax. I am not convinced we have access to all the tables needed. We do have enough to shut it off. But you can use two Pilots and one Main instead. What your doing is very possible with EFI Live at least in a Dmax. You can have completely different tunes for spooling and running down the track. Been doing that for awhile now.
 
Right....I'm kinda thinking pulling the excess fuel at that point might even be a benefit. Exaust temperature goes down with excess fuel past stoch....ideally at the point of
 
Right....I'm kinda thinking pulling the excess fuel at that point might even be a benefit. Exaust temperature goes down with excess fuel past stoch....ideally at the point of snuffing the charger you would want to be at max heat.
 
Joesixpack said:
Right....I'm kinda thinking pulling the excess fuel at that point might even be a benefit. Exaust temperature goes down with excess fuel past stoch....ideally at the point of snuffing the charger you would want to be at max heat.
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Yep Once lit up no need for more than one pulse.

I use the MAF to help keep me from overfueling during spool up. If you get it wrong it acts all kind of stupid. My truck with the MAF limit to low it would stutter and shake and act all stupid like. Back fire out the stack. To much fuel allowed makes it easy to over fuel and put the fire out.

More than one pulse works good for spooling and street driving. Good throttle response and very little smoke.
 
yup lots of good info here for sure
 
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Great info in this thread, this idea does work, im excited to see how far we can go with this!
 
As Johnboy mentioned the post doesn't work well depending on the gen of Dmax, but there are other ways to get the same theory accomplished. Johnboy is right on with over fueling, lean it out and lower the timing until launching, then throw everything back at it. This can be done with efi on TPS settings, rpm, and also MPH settings (to soften the launch).

EFI is the ****z!
 
Yes, it does the same thing on the Dmax, and no, you don't have access with EFI live to all the tables you need, unfortunately. ;)
 
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