Max rpm our 7.3's can effectively turn

[Tim @ P.I.S.]

Are you saying you do not think the FDCS signal can hadlle a 70% DC? If so, why?

I was thinking the DC was up at 80% ??

 

[85_305]

Wow wow wow...I thought I knew a little about 7.3's.

Time to get the box of popcorn out, get to popping, and read this thread 100 times over..

Agreed... these guys are so smart. Love seeing what they have to say.

So I agree with whats been previously asked; why cant we 'mod' the 7.3's oil system to work like a 6.0 to induce more rpm's/hp?

 

[Charles]

Agreed... these guys are so smart. Love seeing what they have to say.

So I agree with whats been previously asked; why cant we 'mod' the 7.3's oil system to work like a 6.0 to induce more rpm's/hp?

Because it would be highly costly, and would not be a wise move for a daily driver considering that it's like stacking a pile of dogsh*t on top of an otherwise highly reliable injector.

And if reliability isn't a concern, nor is money, then there are MUCH better options out there for power than a pos 6oh injector spool.

Like CR injection and Mech injection.

 

[85_305]

So it would be too uneconomical (and unreliable) to stick 6.0 spoolers on the 7.3 injectors?

I agree mechanical and CR make for one very nasty 7.3; of course, the cost of said upgrades is a form of nasty itself

 

[HOOV3R]

So it would be too uneconomical (and unreliable) to stick 6.0 spoolers on the 7.3 injectors?

I agree mechanical and CR make for one very nasty 7.3; of course, the cost of said upgrades is a form of nasty itself

It's not just putting spools in them, you would then need the electronics to actuate them. The reason they can actuate faster is the fact that they travel both directions, which is also the major downfall of them due to the increased wear.

 

[85_305]

****s way over my head, but interesting to learn about and hear from the mouths of the pros

 

[Hotrodtractor]

Well it has been something like 7 years since i have had tuning software so my notes are a bit old. But 39*BTDC?? At what rpm would we use this to refferance? Seems a bit much for say 2K rpm, but maybe not so much for 5K.

But even with those figures you are still pushing past the pcm allowable limits i have writen down.

And i do realize that at say 5K rpm when need to acount for roughly 21* of delay after SOI. As compared to alittle over 8* at 2k rpm.

Disclaimer: this is not gospel., these are figures i have gathered over the years from some solid sourcing, or figures I have gathered from personal testing.

Well - we are talking about what is keeping us from using high RPMs in a 7.3 and you eluded to the IDM being able to do more if it was "unlocked" somehow to release its full potential. I'm just answering the question you asked about the end of the injection event as well as expounding upon the implications of using that.

I used a 70% DC for the FDCS - but the truth of the matter is there needs to be some finite amount of time "off" before it turns back "on" so the IDM can recognize the end of one injection event and the beginning of the next - otherwise it gets confused and starts popping and cracking. Watch this video and listen to the truck - you can hear instances where the **** is confused momentarily:

YouTube Video

I can promise you that the close you push the edge of the ability for the FDCS signal to be generated and interpreted - the more issues you will have - and for any given RPM - the FDCS signal is MORE than capable of giving a good clean power producing injection event well within the confines of an acceptable SOI and duration.

 

[85_305]

^the cracking is due to an IDM getting confused?

 

[Tim @ P.I.S.]

http://www.youtube.com/watch?feature=player_detailpage&v=SRXWmqY8_jY

Working from my phone so maybe this will work.

New setup that was not tuned yet. You can here at the beginning, I believe he said he had it to 5K before it started breaking up. At that point the old tuning was not allowing the injectors to do squat. Haven't heard any progress on it lately. But this is what too short pw sounds like.

 

[golfer]

^the cracking is due to an IDM getting confused?

it's actually the PCM

basically...as rpm increases...the TUNING needs to pull BACK (lower) the inj PW...otherwise the FDCS signal will go into overlap (no 'space' between inj events)...

since the PCM will not command 2 injs to fire at once (one ending its' inj as another one starts inj)...the PCM simply defaults to 0.6ms (ie, a misfire)...so that 'space' can be regained

that's what causes the 'popping' sound...just PCM/chip tuning.

the cool thing is...that regardless of what injection SYSTEM is on a vehicle...CR or HEUI...the maximum (available) PW is the same...


it's just that the CR system can deliver MUCH more volume of fuel in "x" amount of time, when compared to a HEUI system..

the Dmax's, and CR Cummins will 'pop' as well with crappy tuning...and they don't have IDMs.

 

[85_305]

So wait, when our PCM detects a misfire, its default PW value is .5ms???

How does our pcm know if 2 injectors are firing at once?

Why cant we have more than 2 injection events/injector at one instance?

 

[TyCorr]

Wait! Why the hell do you think 2 inj cant take place simultaneously? What would.happen if two.cylinders were fueling on opposite sides of the crank? If the opposing force didnt break rods or the crank the initial time it happened the second or third would for sure. Especially at the rpms this would.take place.

 

[golfer]

So wait, when our PCM detects a misfire, its default PW value is .5ms???

How does our pcm know if 2 injectors are firing at once?

Why cant we have more than 2 injection events/injector at one instance?

the PCM isn't DETECTING a misfire...it causes it.




..why can't I stay gone from this thread.......

 

[TyCorr]

the PCM isn't DETECTING a misfire...it causes it.




..why can't I stay gone from this thread.......

Yea but you making a handful of posts once in a while provides information. This thread will be linked for time to come.

 

[Short Bus]

So wait, when our PCM detects a misfire, its default PW value is .5ms???

How does our pcm know if 2 injectors are firing at once?

Why cant we have more than 2 injection events/injector at one instance?

Are you reading the same thread we are? These guys are laying this out in pretty simple terms, maybe you should read their posts a few times then wait a day or two, read them again, wait a few days then ask a another question. Give stuff time to sink in instead of posting after each damn response!

 

[TERRCO]

the PCM isn't DETECTING a misfire...it causes it.




..why can't I stay gone from this thread.......

Cause you gotta keep correcting misinformation. It's frustrating to think someone will go on something that isn't right.

 

[85_305]

So with all of this talk of the importance of the IDM, is it safe to say that a swamps hf/hv IDM actually does a lot more than some people seem to think?

 

[TERRCO]

We need an emoticon for a car not starting but use it for a thread not starting or going nowhere.

 

[silverpsd_06]

What dave is saying is that as the rpms of the motor go up your duration/window of the crank degrees to efficiently inject fuel gets shorter in actual time the duration never changes just the rpms.
So saying you are wanting to inject 2.1ms at 2500 rpm.. Now take 2.1ms to 6000 rpm there is not 2.1ms of time there to possibly inject fuel. The tuning causes this if the tuner doesn't pull back his pw as the time window gets shorter.

And to have two injection events going at the same time will self destruct the motor. There is alot more to the tuning side of it how they overcome the injection window getting narrower and narrower as rpms increase

The IDM only goes as fast as the PCM commands it to... There is no magical secret to horsepower lying in the IDM

 

[Hotrodtractor]

http://www.youtube.com/watch?feature=player_detailpage&v=SRXWmqY8_jY

Working from my phone so maybe this will work.

New setup that was not tuned yet. You can here at the beginning, I believe he said he had it to 5K before it started breaking up. At that point the old tuning was not allowing the injectors to do squat. Haven't heard any progress on it lately. But this is what too short pw sounds like.

Yep - and by the end of 2008 I could do right about 5200-5250 before it would break up and carry on - but of course it didn't make any power there because of the supreme lack of fuel in the necessary window of time.