View Full Version : 40hp injectors revisited
While browsing Ebay the other day, I saw an ad for the high-flow injectors that will add 40hp. So, I emailed the guy and asked if just changing the injectors alone would give me 40hp or would I need to do some other things to get that hp increase. He responded that no other modifications are necessary - the injectors alone would give a 40hp increase.
I emailed him back asking for dyno results. I also asked him how will they affect my EGT. We'll see where that goes.
Linky for your amusement - http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&viewitem=&item=260102810106
More Power
04-09-2007, 11:56
I contacted one of the 6.5 injector sellers on eBay a while back as well, asking what the pressure and flow rate was for their "Hi-Pop & Hi-Flow" 6.5 performance injectors.
I got a reply stating 2000 psi pop and "more fuel than stock". No peformance data... :rolleyes:
Jim
If the IP is set to stock specs how can the injector allow more fuel to flow.
The IP is only going to pump X amount of fuel in a given stroke.
Sounds bogus to me.
If the IP is set to stock specs how can the injector allow more fuel to flow.
The IP is only going to pump X amount of fuel in a given stroke.
Sounds bogus to me.
I have argued this point many many times. I believe high flows are completely worthless.
Even the idea of timing retardation cause of the flow restriction is difficult for me to accept.
I refer to it as a syringe, if you put 60mm3 in, no matter how big the opening is only 60 is gonna come out!
Well thats the long and the short of it.
I will not even use the high pops.
The only thing I have ever seen them do is make the little beasties rattle more.
I use the standard injectors set to the top of the spec and all of them even.
Now if you are really juicing the IP up then you could see some benefit from a nozzle that can flow more and flow it faster.
Any way I think the only thing these items do is make money for the seller.
The local rebuilder and Stanadyne shop here just roll their eyes when you ask them about such things,
Robyn
I do rebuillt the injectors myself , and I observed that upping the pop pressure will give a better and finer spray wich will help especially at slow crankingspeeds to aid starting.
I have on one 6.5 injectors set at 2200 psi that some claim is to high and will harm the IP.
I talked to my pumprebuilder about this and he said not to worry ,that the rollers and cam are the same ones used as in some John deere aplications and they run at 2700 psi
If this retards the timing, I have seen no evidence of it.
My two cents worth.
neepsjeeps
04-09-2007, 20:00
Anyone know the real pressure of a 6.5 turbo injector? i have heard at least 1700psi, but since im thinking around 1900-2100 is more where i need to be? maybe its at least 1700 as a tolerance?
Also anybody know, i read that each thousand of a inch gains 55psi in pressure? sound about right?
TurboDiverArt
04-10-2007, 04:43
Knowing a little about injectors, pressure will effect the spray pattern. I agree that as long as the injection pump is dumping all of it's fuel out the injector then pressure is not going to effect the fuel flow. The pop pressure could have either a positive or negative effect on the spray pattern. Without having tested our injectors at various pressures I can't really comment on the effect it has on the spray pattern. What I believe has a bigger effect on the spray pattern is the nozzle that's used. The nozzle needs to be matched to the pressure range to get the correct pattern and atomization.
What nozzles are generally considered to be the best atomizing for our trucks? I know it's been stated in the past (nozzle part number) but I can't seem to find it now. I've asked this question before. Are the new stock injectors now using the same nozzle as the ones that people are using when rebuilding these hi-pop or stock rebuilt injectors? I'm going to be replacing my injectors this summer so I need to get off my butt and decide on which to use.
I don't understand why hi-pop injectors are so much more expensive than stock rebuilt injectors. Both are pulled apart and cleaned, both usually have shims to set the spring pressure and both have replacement nozzles. I don't understand why hi-pop
ronniejoe
04-10-2007, 08:05
The syringe analogy falls down in a couple of ways: First, there is no spring loaded valve in the syringe and there are no return lines in the syringe...as we have with fuel injection nozzles.
Let's keep the syringe analogy, though, briefly and consider a couple of different orifice (nozzle) sizes. Lets say we have 50 ml syringe with water in it and on the end is a needle with a 0.030" hole. Assume the syringe plunger stroke covers the full displacement in one second (for talking purposes, I'm not actually planning to calculate this). When the syringe is full and the stroke has not started, the delta P across the orifice is 0 and we have no flow. When the plunger begins to move, there is a period of acceleration and increasing delta P across the orifice, which yields an increasing flow rate. When the accelaration period is over, there is a period of constant speed displacement of the plunger yielding a constant flow rate through the orifice. Towards the end of the stroke, the plunger must decelerate to come to a stop. This yields a decreasing delta P and decreasing flow rate.
The size of the orifice determines the delta P and fluid velocity for a particluar stroke cycle time. If we change the orifice from the 0.030" above to, say, 0.010", we get a very different result. If the plunger stroke cycle time stays constant, we will see increased delta P and increased velocity of the fluid through this smaller orifice. We will see finer fluid droplets spraying out as well.
The same thing is true in the injection pumps on our trucks. There are ramps on the cam ring that have carefully designed parameters to control the acceleration, constant velocity and decleration portions of the plunger stroke. Therefore, we have the same varying pressure curve with increasing, constant and decreasing periods as described above. The kicker is that we have a spring loaded valve covering the orifice. This valve allows no flow until the delta P reaches a pre-set level then the valve "pops" open. Therefore, if the stroke cycle paramaters remain constant and the spring force is increased from some standard value, there will be a definite delay in the opening of the valve as compared to the standard spring setting. This is retardation of the injection event. It is a very small delay (probably microseconds), but a delay none the less. On the other end of the stroke, when the plunger is decelerating and the delta P is decreasing, the valve will close sooner than the standard because the spring can force it closed against a higher pressure. In essence, the injection window is slightly narrower with a higher pop setting. When the valve closes, there is still fuel being displaced by the pump...that is why we have the return lines to bring that extra fuel back and vent the nozzle to prevent a build up of residual pressure.
In this instance, the orifice size (nozzle size) remains constant. Therefore, the higher delta P will cause an increase in the velocity of the fuel through the nozzle, resulting in a finer spray with smaller droplet sizes. Again, in this case, the actual fuel delivery is probably slightly less than with standard settings on pop pressure, but you probably have improved burn characteristics from better atomization. Some of the improvement in atomization comes from the higher velocity, some comes from the increased delta P. The expansion velocity increases as delta P increases resulting in a finer spray pattern.
Now let's increase the size of the nozzle or orifice. We can bring the flow velocity back down (all the way to the standard velocity if we want to) some and get more of the fuel into the combustion chamber during the shortened injection window instead of sending it back through the return lines. We still get better atomization than standard because the spring forces us to operate at a higher delta P across the entire event but not quite as good as when we left the nozzle area alone. In this scenario, the amount of fuel going into the combustion chamber can be exactly the same as that in the standard case; however, it is entering the chamber under higher pressure and atomizes better which yields a better burn and more power.
If you increase the nozzle flow area further, you can actually increase the amount of fuel delivered to the combustion chamber. Not by a lot, but by a little.
This discussion actually ignores some other factors. The actual displacement of the pumping plunger is huge in comparison to what actually gets sent down the injection lines to the nozzles. For instance, the DS4 pump displacement is actually over 138 mm^3 per power stroke, but maximum fuel delivery is always stated as 80 mm^3 per power stroke (or injection event). The fuel solenoid comes into play here and is another valve in the system. Using the fuel solenoid actually takes the effect of the acceleration ramp and deceleration ramp out of the equation by not sending fuel down the line until your in the main stroke of the plunger. The excess fuel is circulated around the pump for cooling and back to the tank.
We still have an increasing pressure period and decreasing pressure period at the nozzle because it takes a certain amount of time for the solenoid to move from full closed to full open, so the basic principles discussed above should apply.
I should add a disclaimer:
I am not a pump expert and any number of things in this discussion could be completely in error. However, I have spent a lot of time thinking about this from a theoretical standpoint and it seems to make sense. I have never taken one of these apart, I've only studied diagrams, photos of disassembled pumps and cutaways that I've run across over time.
Reader beware!:cool:
dieseldummy
04-10-2007, 08:58
I'll have to say that what RJ just posted pretty much sums it up. I've argued with the syringe theory before for the same reasons. Like I said before it's all about duration with the bigger nozzle. I used to be a believer in the idea that nozzles made no difference and that ultimate fuel delivery was in the pump. I took the leap to built a set of injectors with marine nozzles and found out different. Our pumps are very limited in the amount of fuel they can deliver without some serious modification, so for the average user the marine nozzles provide that extra "edge". I can't say that they are worth 40 HP, but I did notice a big difference SOTP. Especially in the upper RPM range.
I still challange AndyL to take a 60cc syringe, a 18ga needle, a 14ga needle, and a stop watch. See what happends when each needle if fitted to the syringe. I'll bet the difference in the time it takes to empty the syringe will be noticable. It may not be a big difference, but remember at 3500 RPM's a split second is eternity...
I'm no mechanic but I have successfully ( and most probably very luckily , because I should have pop tested each injector) replaced nozzles, cleaned injectors, oiled them with ATF, and carefully placed each injector back into the same cylinder. I foolishly didn't pop test them, but it was obvious to the naked eye that the number 2 injector didn't have enough load and needed a shim. ( It was about 1/16th off from the other injectors.) I took that injector to a diesel shop. They put a shim in and pop tested it in about 5 minutes, no charge! And what a hugh difference it made on that high mileage auto engine ( at that time it had 312,000 miles on the od ) in all areas, from power to idle, to easy starts, to no smoke, etc... Maybe I would have had the same results had I merely replaced and shimmed the #2 nozzle... But I strongly suspect those new Bosio nozzles also markedly increased the HP.
However, I remain a skeptic in all areas. Yet since the Europeans get about 30hp more from their TDI's, simply because it seems the nozzles in injectors used in Europe have a finer, broader mist, then I strongly suspect that one can indeed increase HP by replacing existing nozzles with those with better spray patterns,
neepsjeeps
04-10-2007, 09:26
So what i get is a injector with a marine tip set a a higher pop point than a standard injector set at a lower point, would better atomize the fuel..
im not filling in the math, but i can see the idea, anybody know what the pop settings would be with a marine injector nozzle vs a stock type nozzle? and is it something you would measure as a flow rate or something (to find the right pop point)
i wish i had two sets of injectors, i would build a set of each and dyno the truck and see if there is any difference at all...
P.S. i have a 93 with a db2, i know its a two plunger pump, what would marine do with that? or is it a waste unless i build a 4 plunger marine pump?
Well now
The time curve based on the size of the orifice does make sense.
I may just rethink my opinion on this subject.
But as Jim has mentioned.. Dyno results would be very interesting.
Take a good running stock 6.5 with either DS4 or DB2 and do a dyno run, chassis or engine.
Keep the test parameters all the same except for changing the injectors from a set of new stock units to a set of the 40HP trick ones.
You would have to compare new with new to get good results for sure
Would be very interesting to see the numbers.
I beleive that this would be the only way to do it and know for sure.
Many times we can anticipate improvement and we hope for so much that we feel it no matter what actually happens.
I know this to be true, been there done that many times myself.
To do this would be very easy with a chassis dyno and a good running truck.
Maybe this can be arranged???
Robyn
Yet since the Europeans get about 30hp more from their TDI's, simply because it seems the nozzles in injectors used in Europe have a finer, broader mist, then I strongly suspect that one can indeed increase HP by replacing existing nozzles with those with better spray patterns,
I think you're talking about a common rail system now. Completely different set of rules apply.
I think you're talking about a common rail system now. Completely different set of rules apply.
No, I was refering to Turbo Direct Injection, which I seem to remember was first produced in the mid 1990's. It seems the Europeans quickly latched onto the Italian Bosio nozzles which produce a finer mist and wider spray pattern which ups the little VW TDI from 90HP to 120HP. Bosio also produces nozzles for other cars and trucks, including GMC.... But, alas, none for the old 6.2L I recently bought...:rolleyes:
I seem to remember that Common Rail wasn't produced until 2001 and deals with much higher pressure and now Delphi has just introduced a third generation Common Rail Direct injection with a very different injector. I rather doubt that Bosio or any other nozzle maker will soon best the Dephi injector made specifically for their new generation Common Rail.
I couldn't exactly remember where I got the notion that Europeans had upped the HP on their TDI's by replacing the nozzles with Bosios. So I made a search and came up with a link to the makers of Bosio nozzles.... which just may be pure hype. :o Then, it could also be true, or somewhat true....;)
http://www.kermatdi.com/servlet/-strse-template/faq/Page?template=sprint (http://www.kermatdi.com/servlet/-strse-template/faq/Page?template=sprint) or
http://www.kermatdi.com/servlet/-strse-template/faq/Page?template=nozzles
neepsjeeps
04-10-2007, 18:04
I couldn't exactly remember where I got the notion that Europeans had upped the HP on their TDI's by replacing the nozzles with Bosios. So I made a search and came up with a link to the makers of Bosio nozzles.... which just may be pure hype. :o Then, it could also be true, or somewhat true....;)
http://www.kermatdi.com/servlet/-strse-template/faq/Page?template=sprint (http://www.kermatdi.com/servlet/-strse-template/faq/Page?template=sprint) or
http://www.kermatdi.com/servlet/-strse-template/faq/Page?template=nozzles
The bosio injectors are high quality injectors for euro cars, thats why your not understanding what he is posting.
they are similar injectors (the old mercedes injectors) to the style we are using. bosio doesnt make nozzles for the gm injectors, but you could make a comparison to bosch nozzles, however without knowing the specs or the mb pump, trying to say different nozzles would act the same, just would be guessing.
in a old MB Diesel adding these nozzles adds power, but its a different critter and oranges may be like apples but still its not the same system...:)
The bosio injectors are high quality injectors for euro cars, thats why your not understanding what he is posting.
they are similar injectors (the old mercedes injectors) to the style we are using. bosio doesnt make nozzles for the gm injectors, but you could make a comparison to bosch nozzles, however without knowing the specs or the mb pump, trying to say different nozzles would act the same, just would be guessing.
in a old MB Diesel adding these nozzles adds power, but its a different critter and oranges may be like apples but still its not the same system...:)
True, but I like the Bosio nozzles that I put in my old MB so much that I sent the guy an email regarding Bosio's in my 6.2L.... after all, they make them for the Chevy Duramax: http://www.kermatdi.com/servlet/-strse-Chevy-Duramax-LLY/Categories
neepsjeeps
04-10-2007, 19:42
im sure they could make them, but really the 6.2/6.5 injector isnt going to be a big ticket item, so i would not hold your breathe...
I think the one key thing these guys are missing is the true definition of high pop. I won't state what we use for high pop, but it sure seems many are low by our standards.
.... after all, they make them for the Chevy Duramax:
Now I know you're talking about common rail...
;)
I think the one key thing these guys are missing is the true definition of high pop. I won't state what we use for high pop, but it sure seems many are low by our standards.
Not that wetted my curiousity. :D Why won't you say what you use for high pop? Surely you share that info with your customers... And are we not at least potential customers?
john8662
04-20-2007, 13:15
"Hi-pop" vs "Marine" vs "Marine Hi-pop"
Hi-pop could be any nozzle, set at higher pop pressure.
Marine is the use of the "311" nozzle, larger oriface (more fuel).
Marine Hi-pop, use of the 311 nozzle in conjunction with a higher pop pressure, getting the advantages of injecting approximatly same amount of fuel as a stocker but at a higher pressure in a now smaller injection time due to higher pressure.
But, the cobinations do vary, depending on builder as JK hints.
J
"Hi-pop" vs "Marine" vs "Marine Hi-pop"
Hi-pop could be any nozzle, set at higher pop pressure.
Marine is the use of the "311" nozzle, larger oriface (more fuel).
Marine Hi-pop, use of the 311 nozzle in conjunction with a higher pop pressure, getting the advantages of injecting approximatly same amount of fuel as a stocker but at a higher pressure in a now smaller injection time due to higher pressure.
But, the cobinations do vary, depending on builder as JK hints.
J
Thanks for the info! Have you heard of the flatter cut nozzles that many Europeans are using to burn Veg oil? Apparently they give a very good pop. When I get ready to change the nozzles in my 6.2 I'd like to gloom onto 8 of those. In the meantime I'm putting together two VO heaters. One right after the 2 micron Racor fuel filter/ water separator and just before the IP, and the other near the rear tanks.
I changed the nozzles on my old MB and had good luck by replacing each injector back into the original cylinder. Dumb luck, I guess. Next time I'll first build a pop tester as shown here: http://s42.photobucket.com/albums/e303/mohoneywell/grease%20and%20bio/?action=view¤t=attachment.jpg
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