80-100hp/no EGT issues/4-6mpg> miracle inj installed Friday

[DanDee]

George, back from your trip ? Anything more on the new injectors???



(Sorry, I know it's early Monday morning... . but couldn't wait!!!!)





DanDee

 

[DPelletier]

Moving the probe may, or may not, improve the EGT readings but it doesn't change the fact that the EGT's went way up compared to the stock injectors. Hmmmmm.

Looking forward to your next report.



Dave

 

[geusterman]

OK... next report. Just back from Pasco and a mileage test with Chad. I could not seem to get much above 14 even with lots of highway and went to Pasco to reinstall my stock injectors. Chad asked if we could do a mileage test before hand and in fairness I agreed. Dumped the camper at the RV park and met Chad this AM, and with his kids we went to Tosoro to fuel up. Now... . and I am somewhat embarrassed about this... I am in the middle of a flatbed build-up with 2 tanks. I have a leak on top of the factory tank (perhaps where I added the vent in the high spot... have not looked yet) and my welder inadvertently put a "trap" in the shared ventline that goes up into the headboard. When the fuel ran out without foam we took off... . with a good drip going that would last through the burning of the fuel in the intake spout. Chad drove us (his 2 cute kids) up highway 82 for 40 miles and back to Tosoro. We filled 4 gallons to runout... dripping as well underneath. BUT... instead of putting the cap right back on I was talking with Chad and the tanks burped due to the retarded vent line. I then added another gallon and a third which took the mileage from 20 mpg to 16 something... which could have been possible stock... but never accomplished before. Did it "burp" after I filled it before the trip? Don't know as I put the cap on so quickly. NEEDLESS to say... I need to get the fuel tanks worked out to be fair to Chad. He and his partner Scott are quite convinced, based on their experiences, that these injectors should give 20 mpg. So the project goes on.



Additionally, regarding EGT's, Chad's responce is that Wyotech (some tech shop I don't know about) is convinced that egt's should be measured post-turbo based on flame interferance. According to Piers today (by phone), Cummins says 1350 pre and 1050 post. Stock 600's have claimed 1350... I have never seen over 1250 but not over 12K in weight and perhaps would heavier. Chad says all commercial rigs run post turbo and his wife's Gen 3 lays down 430 rwhp with stock turbo/exhaust and never over 1050 post turbo. Piers has measured both and with boost of 40 has seen 500 degrees difference. Chad says that he has never seen an issue with post turbo held to 1050 no matter the "improvements. " I asked him if flame would be present if I pulled the pre turbo pyro from my manifold and he said "big time if you were on the go pedal". But not post-turbo.



If I can get the mpg's I will move the pyro. Got a long trip to DC for 5 weeks coming up mid Sept so this project may not get resolved for a while. Sorry about that. Chad has my stock injectors waiting on a shelf if I want them back and he has been more than willing to replace his injectors anytime... even if they work! Their shop has some marvelous Cummins projects going on and lots of performance stuff and a long drag racing history so I want to continue this thing. There could be a real neat product here... . they think so. Chad's shop number (Diesel Performance Unlimited) is 509-546-9997 which Piers asked me to post as someone posted it wrong earlier in the thread. Later... George

 

[KLockliear]

MOVE THE PYRO. The bigger the restriction that the turbo is (and we all know that tiny HY is a big restriction) the less heat you will see post turbo. All performance applications should be run pre turbo!

 

[MCrossley]

Something to remember about our diesels and the OTR trucks is that they are no where near running at max output of the engine like we do so to say they run post turbo without problems is not a fair comparison at all... Pre Turbo is where the fire is yes it is also where the pistons are not in the turbo; I would have great caution with running anything past 1350 on the pre-turbo as we have seen more than our fair share of #6 pistons melting at 1400 on the 24v engines Chad does not sound all that smart in regards to the longevity of your engine. I hope all works out well but buyer beware of the temps we have been playing the big injector game now for a long time not much is going to change in regards to temps and fuel and the longevity of the engine...

 

[1badplr]

Injectors

I have found a great guy to deal with on the injectors for the gen 3's. He is loacal and has the ability to get them back in two day's. Oo. I have also found his prices to be unbeatable! PM me for details.

 

[geusterman]

Keith... I am pre-turbo. Thinking about changing to post if I got the mileage. Appreciate your input. George

 

[KLockliear]

Stay pre. If you want to see post, add another gauge, but MAKE SURE you have one pre turbo, especially in any performance application.

 

[DLeno]

I always get a chuckle out of the pre-post discussions because to me its a flat out no brainer for power enhanced trucks. Sure, when you operate under stock conditions (no mods) you can rely on Cummins data that says 300 degree differential temperature. My point is that there is not much margin left in the stock huffer, so when you add fuel, you easily push it outside of its operating map. ok, make sure you ask yourself: what does that MEAN? it means that you can no longer depend on that 300 degree differential temperature and you have to start directly measuring the things that matter -- exhaust manifold temps. think about it -- you have an air restriction where the turbocharger is the weak link (it cannot pass enough air). Well I dunno, what do you think will happen if the manifold temps were to rise very quickly in the presense of an air restriction not capable of exhausting enough air to cool things down? all of a sudden your post-turbo thermocouple is fat dumb and happy while your pistons are changing shape



Even if you place your thermocouple pre-turbo you have the following errors to account for:



1. precise placement is sometimes a compromise and an art. we can do pretty good at locating the install point, but no one really has proven where the hottest position is. that would require too many holes in the manifold . individual pistons will differ according to how well balanced the injectors are, mechanical design of the engine, etc. ok, so allow 50 degrees for that.



2. Some theromcouples are fast, some are slow. beware and see TDR issue #34 page 20. You'd be surprised at who is near the bottom of the speed list. when you punch it, you don't want a lazy thermocouple to make you blind as to how quickly your EGT really rises. so allow 50 degrees for that. now we're up to 100 degrees in error.



3. some gauge faces themselves are faster than others. it takes time for that needle to get there. most gauges are fast, so we'll let this one slide



4. Some EGT gauge systems are inherently in error especially on hot days. Did you know that your EGT gauge does not actually measure the temp of the thermocouple probe? Thats right: it measures the difference between it and the "cold" end of the type-K wire. Beware of thermocouples that have ordinary copper wire under the hood. They can read as much as 100 degrees too cold if your engine compartment is hot. Its always best to have a long "type K" lead that terminates in the cab. What assumption for the temperature of the "cold" end of the thermocouple has your guage been calibrated with? One way to get around this problem is to put the "cold" end of the type-K wire in the cab and calibrate the gauge to expect that this cold temperature is 70 degrees. Then your measurement is accurate to within 10-20 degrees depending on cab temperature -- perferctly acceptable. The best way to avoid this problem is to use a temperature compensated gauge -- then your measurement is accurate to within a fraction of a degree. the worst way is to put the probe under the hood where the temperature of the "cold" end is all over the map. One EGT gauge manufacturer I spoke with ("cold" end under the hood) could not even tell me what assumptions they made in calibrating the gauge. I guess they figured no one would care to understand any of this.



So consider all the sources of error in the pre-turbo EGT gauge. at least 100 degrees for a reasonable quality guage, and 200 degrees for a slow one. then add another 100-300 degrees of error for the post-turbo install and ask: do you have anything that is meaningful for the purpose you intended?

 

[KLockliear]

2. Some theromcouples are fast, some are slow. beware and see TDR issue #34 page 20. You'd be surprised at who is near the bottom of the speed list. when you punch it, you don't want a lazy thermocouple to make you blind as to how quickly your EGT really rises. so allow 50 degrees for that. now we're up to 100 degrees in error.

DL, I'm not arguing with you here - what you say about the speed of the gauges is true, but let's analyze what the pryo is telling us as well. We found that the open tip pyros are much faster to respond than the closed tip pyros. If you stab the throttle, the open tips jump right up to a given temp, where the closed tips move more smoothly.



Now, perhaps the open tips give us a better reading of the actual EGT, but what are we looking for in the EGT reading? Do we really care what the temp of the exhaust is? I don't think so. What we really want to know is how hot is the cylinder temp and REALLY - how hot is the piston itself. Well, EGT may jump to 1600*F, but due to the mass of the piston, the oil cooling, etc, the piston temp will climb relatively slowly in comparison to EGT. This is why we choose to stick with the closed tip pyros.



In reality, we can't know when the piston is going to fail precisely. EGT is just a gauge. As long as you don't hold it at some absurd temp for long, it will likely be OK. Again, just another waypoint in the path of life.

 

[DanDee]

Wow! Once again I'm truly impressed with the fantastic amount of information AND the quality... . all due to some of the most knowlegeable people in ANY forum I've ever seen!



Wish I could find quality forums like TDR for the multitude of other things in life!!!



Thank you and keep up the good work! TDR is the best!



DanDee

 

[DLeno]

no argument from me, Kieth. the "fast" versus "slow" thermocouples I refer to are all closed -- filled with I think a ceramic material that both insulates the probe from chassis ground, and conducts heat from the gasses into the actual K junction.



I'm just pointing out that the averaging effect of a slow thermocouple can get you into trouble if you don't understand the information it gives you, and that among the closed thermocouples available today, there are some that look astonishingly slow to me. ultimately I think understanding the behavior of a particular gauge is more important than getting the fastest one. After all, the purpose of the gauge is so that we can react to the data -- back off the throttle. and some gauges inherantly cause more time before actual EGT relief than others, simply because they are slow.



In particular, the TDR data indicated (to me) that there were one or two closed-end thermocouples that took so long to reach 1600 degrees that I would question their use as part of an accurate pre-tubo pyro.



ultimately, the mfgs like you guys that correlate actual performance with open tip 'couples and understand the behavior of their gagues are the best equipped to vouch for gauge accuracy. Its the ones that don't do this work I'm worried about -- as if you're supposed to just stick something in the manifold and expect it to be accurate without understanding some of the important variables.

 

[DPelletier]

Keith and Doug,

Good discussion! I'm no expert, but I will only run pre-turbo (unless I have two gauges) because ultimately the health of the HY is of little importance to me compared to the health of number 6 piston!



Thanks

Dave

 

[KLockliear]

Good deal Dave. Just be aware, it is not ALWAYS the case that #6 is the hottest.

 

[Lorenz]

Probe and Manufactures

so the real question is, how do i tell what pyro tip i have.



could some one look up #34 issue of TDR and post the findings for the rest of us.



Ive have a westach dual gauge w/supplied probe... am I running a fast or slow set up?

 

[GWoody]

"could some one look up #34 issue of TDR and post the findings for the rest of us"



Some of us don't have that issue, names man we want names, let's talk brands, who is the best and who is the worst, c'mon boys spit it out, we want to know.

 

[GWaggoner]

Not to sound like a butt head here, but the thread about the new injectors not really helping the fuel economy but 2 mpg, is it on hold for more test data, or was it observed that the new miracle injector was getting similar as the old miracle injector?



I am very interested in the findings of geusterman and his report on this new injector, and as DLeno says, all the talk about pre-post thermocoupler mounting brings a chuckle everytime. Its a worn out subject.

 

[blake underwood]

Been runnin' DPU injectors for about a year now. Never got less than 20 mpg on a road trip. I can't tell ya my MPG I got before my mods, because it wasn't stock long enough . My best mileage to date was just a couple of weeks ago on my trip down hear to Arizona. I went 711 mi. to 30. 6 Gal. of Diesel. This was avg. 75-80 mph almost the whole trip. Oh, and I probably could get better MPG, but I like to go fast and race people !

 

[GWaggoner]

Blake,

It looks like you have several thousand dollars worth of upgrades to get 20mpg. Most of the trucks here seem to be getting 15-16 mpg in 4x4 config. have you dyno'd yet to see the final output? I am interested in most of you upgrades a little at a time, and hope to have that end result, but its the throwing another 5k at my truck thats a little hard to stomach. What injectors are you running?

Gary

 

[DLeno]

I'll look up the thermocouple story. I just don't have the issue in front of me. I do know that Westachs are among the better ones. Accurate, fast enough, long type K wire with the cold junction, and calibrated with the assumption that the cold junction is at 70 degrees -- Doug