Dmax RPM Limit??

JQmile

JQmile

Comp Diesel Sponsor
Joined
Nov 19, 2006
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Who's turning 4500+ and still making power? How? EFILive?
 
Seen a vid of a puller a while back a green truck with a dmax...can't think of the name but it was hela strong if I was to guess it was running a stand alone.
 
I'm curious as well. I think some were complaining that efilive didn't support much over 5k. I haven't verified that rumor.
 
I'm still kicking around swapping a dmax into my Nova, and I want to go with a TH400....no lockup means lots of rpm to get that converter efficiency up.
 
4800-5000 is about the limit of what the stock ECM can support with EFILIVE(I've hit 4900 with mine just playing around free revving it before), and I believe PPE also allows you to turn up that high with there tuners. The limiting factor as I understand it has been the heads and intake. Unless you do a good porting on them, they tend to not make alot more power once you get up into the higher RPM's. Never heard of anybody running a stand-alone as 5K RPM's is alot and can be done with a stock ECM and EFILIVE.
 
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The stock LB7 & LLY ECM can handle 5500 RPM the LBZ and newer can go a little higher. The bigger issue is getting the fuel system to handle what needs to be done. One needs to learn to do a little math and figure out the amount of TIME that you have to get the injection events done, where it needs to be, if you want to begin to see what's causing the issues. I have run over 5500 but its not easy and is expensive. A stand alone is NOT going to solve the fuel system issues, so start there first. Here is an example of what your looking at.

RPM time
1000 6666.7
1500 4444.4
2000 3333.3
2500 2666.7
3000 2222.2
3500 1904.8
3700 1801.8
4000 1666.7
4500 1481.5
5000 1333.3
5500 1212.1
6000 1111.1
6500 1025.6
7000 952.4

So if you want to turn 5500 RPM and make "X" power you need to be able to deliver the necessary amount of fuel in 1212.1 uS. There currently is no off the shelf parts that will do that, if were talking about real power here! So they are all custom built and that cost more than most are willing to spend. The controller side is not the major problem but it is one of them. Free Rev's don't count here, as what I'm talking about is making full power.
 
Diesel Tech said:
The stock LB7 & LLY ECM can handle 5500 RPM the LBZ and newer can go a little higher. The bigger issue is getting the fuel system to handle what needs to be done. One needs to learn to do a little math and figure out the amount of TIME that you have to get the injection events done, where it needs to be, if you want to begin to see what's causing the issues. I have run over 5500 but its not easy and is expensive. A stand alone is NOT going to solve the fuel system issues, so start there first. Here is an example of what your looking at.

RPM time
1000 6666.7
1500 4444.4
2000 3333.3
2500 2666.7
3000 2222.2
3500 1904.8
3700 1801.8
4000 1666.7
4500 1481.5
5000 1333.3
5500 1212.1
6000 1111.1
6500 1025.6
7000 952.4

So if you want to turn 5500 RPM and make "X" power you need to be able to deliver the necessary amount of fuel in 1212.1 uS. There currently is no off the shelf parts that will do that, if were talking about real power here! So they are all custom built and that cost more than most are willing to spend. The controller side is not the major problem but it is one of them. Free Rev's don't count here, as what I'm talking about is making full power.
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How many crank angle degrees are you using for that injection window table?
 
Those numbers are on the conservative side. That is the bugger of the common rail though. There are injectors that will do very well up there though.
 
1800us is working for me at 5000. It would be cleaner if it were 1400us, but I'm not complaining.
 
JasonCzerak said:
The higher the revs the bigger the nozzle requirement?
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From what I have heard it takes a bigger injector to keep the pulsewidth down, and that is a contributing factor inregards to rpm, the longer the pulse the less rpm at a certain point.

I'm sure if you weren't shooting for big power as well you could make one rev without big injectors.
 
Joesixpack said:
Those numbers are on the conservative side. That is the bugger of the common rail though. There are injectors that will do very well up there though.
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Well you may believe they are conservative but try making 1600 HP at those RPM's and they are anything but conservative. The injector size is going to be ruled by the power your trying to make at "X" RPM. So if your shooting for 800 HP it is completely different than shooting for 1600 HP! Once you cross 800 HP things take on a whole new life and the injector body, injector tip and common rail all start to show the problems as the power goes up.

The amount of time you have in crank angle is all pretty straight forward based on piston bowl design and position in the block along with injector spray and position.
 
Diesel Tech said:
Well you may believe they are conservative but try making 1600 HP at those RPM's and they are anything but conservative. The injector size is going to be ruled by the power your trying to make at "X" RPM. So if your shooting for 800 HP it is completely different than shooting for 1600 HP! Once you cross 800 HP things take on a whole new life and the injector body, injector tip and common rail all start to show the problems as the power goes up.

The amount of time you have in crank angle is all pretty straight forward based on piston bowl design and position in the block along with injector spray and position.
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Well I relating what I know about the cummins, and for it those times are short. The dmax with less stroke would be giving up a bit of dwell time alright, but still can't be that much.
 
Joesixpack said:
Well I relating what I know about the cummins, and for it those times are short. The dmax with less stroke would be giving up a bit of dwell time alright, but still can't be that much.
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The numbers above are a 40 crank angle degree injection window. I know for a fact that I can run up to 54 without sweating on a 2005+ injector/piston combo. Pushing much beyond that doesn't really net anything. However, putting in any fuel >20 ATDC is serious smoke/heat.
 
joefarmer said:
The numbers above are a 40 crank angle degree injection window. I know for a fact that I can run up to 54 without sweating on a 2005+ injector/piston combo. Pushing much beyond that doesn't really net anything. However, putting in any fuel >20 ATDC is serious smoke/heat.
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I agree you can run what you want but what power level are you making, that you say 54 degrees is OK? As the amount of fuel goes up, as required to make more power, the time window comes down. So what you can get away with at 800 HP doesn't come close to working at 1600 HP.

While some may disagree with the numbers the simple physics of it comes into play and bites us in the ass. I for one have had to learn that the math does a pretty damn good job of telling you what you need upfront. I've busted enough stuff testing and racing to know better now days.
 
54 CADeg was ~1040 rwhp. I agree with you as well- the physics must support the injection. I've had several injector manufacturers laugh at me when I requested xxx mm3 @ 1000us. They'll figure out a way eventually, I'm sure.
 
I know some turning 5K plus are running ungodly big injectors for time purposes.
 
The injectors I'm running flow more at 1600 micros than exergy's biggest set at 2800.

If in doubt, PPUMPIT!
 
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