How can pressure boxes be safe ?

[CraigJones]

I did some searching on the internet. From what I've found my 305/555 max. pressure is 23,500 psi. How can these boxes say its safe to crank it up to 26,000 psi,this can't be good as far as long term reliability. Hers's a link I found about the bosch common rail in the dodge cummins. Does anyone have more info. Thanks

Bosch Common Rail in Dodge Cummins

 

[rbattelle]

this can't be good as far as long term reliability.

In my opinion, it isn't good for long term durability. But that's not the point. Most truck owners don't keep their truck beyond 100k miles or so, so if the fuel system is going to die at 200k, who cares?



In another thread Matt400 mentions that Bosch says the CP-3 can handle up to 30k psi without trouble. I suppose the weak link, then, is the plumbing. I think the pressure limiting valve opens at around 26,500 psi, so the box manufacturers simply work inside that limit.



You don't buy a power-enhancing box because long-term durability is your primary concern. You buy one because gobs of power is your primary concern. And that's just fine... it all depends on what you want out of the truck.



-Ryan

Disclaimer: I am not trying to say that anyone is "bad" or "dumb" or anything else bad in this post. I'm simply relaying my opinion on the question. I mean no ill will toward any person or group of people. If I've said anything wrong, I will gladly accept correction.

 

[jcarey]

A pressure may be a good stack, using the lower settings to keep rail pressure in the moderate range. Anything more than that and I think I would go with a TST or maybe the Edge/Juice Attitude when/if it comes out for the 2003.



However, I think I read a post by DLeno where he did some testing and found that some pressure obxes keep the rail pressure up even on the lower setting. Not up near the limit but mid-range. However, I think I read a post by DLeno where he did some testing and found that some pressure obxes keep the rail pressure up even on the lower setting. Not up near the limit but mid-range.



Injectors and some boost fooling mechanism may be a good alternative.



Hope this helps,

Jim

 

[FDavid]

With the Bullydog downloader and EZ stacked on Max settings, reading off the datalink, I could hit 28,000 psi pretty easily.



Probably drove 3000 miles on that combo and it never caused any problems.



I remember reading a post a while back about someone who worked in the service dept. of a Dodge dealer and said so far they every set of injectors they have had to replace on a 3rd Gen truck with over a 100k was due to a pressure box.

 

[jcarey]

You can always treat as 'fact' vendor claims/stetements. They are trying to sell you something.



Little more info:



Extracted from Bosch articles:

--------------------------------------------------------

The Bosch common rail system is featured on the new Cummins 5. 9 liter ISB-E engine. The inline six-cylinder engine is the most powerful turbo diesel engine available in the 2500/3500 segment, producing 305 horsepower at 2,900 rpm and 555 lb. -ft. of torque at 1,400 rpm.



Common rail is a fuel injection system that separates pressure generation and injection events, providing engine manufacturers with a large degree of application flexibility for meeting stringent emissions. The Bosch common rail system is capable of injection pressures up to 1600 bar (^23500psi).



The Bosch third-generation common rail system operates at a maximum working pressure of 1,600 bar (model year 2003), and will expand to 1,800 bar by 2005.



Bosch currently is developing two concepts for its fourth-generation common rail, the next technological advancement to the common rail system. Both designs are intended to provide injection pressures of more than 2,000 bar. One of the fourth-generation design concepts utilizes a combination of piezocontrolled injectors and a vario-jet nozzle spray hole geometry. Improvements in the fourth-generation system will support further reductions in engine emissions, engine-specific fuel consumption and combustion noise, while increasing available engine output. Bosch plans to unveil the new system in 2006.

--------------------------------------------------------



Some articles here:



http://www.boschusa.com/News/ViewNe...wsType=PR&ID=53



http://www.boschusa.com/News/ViewNe...wsType=PR&ID=17



Jim

 

[JVolpe]

IMHO the answer to the somewhat rhetorical question is that in general they cannot be safe. Of course I have tried one or two. The first one scared me because of very rough engine idle, high EGTs and reports of 27000psi rail pressure. The second is mostly timing and duration with a little fuel pressure.



Unfortunately I cant resist, so I am now a Warranty provider. Maybe the 4th Gen Bosch systems can be adapted to my 325/600. HHHMMMMM where is that pressure box I took off.

 

[qzilla]

SO if they are not safe, show me how many failures we have seen because of them?



Remember that pressure boxes don't jsut increase the max. rail pressure. We can go in and tailor the pressure curve to meet the conditions at a given time. Take pressure, add a little duration and some timing and you have a winner.

 

[jcarey]

SO if they are not safe, show me how many failures we have seen because of them?



You sound sooooo defensive :-laf

 

[JVolpe]

I can not give you any failures other than mine. I will not go into any manufacturer names or products. I dont have experience with most. I did state IMHO (opions are just that). I had a pressure box on for about a month. After few hard runs in the quarter the engine ran so rough and idled so bad and sounded like an old sewing machine my mother used, I removed it. Shortly after had to have #6 injector replaced. May still have an injector that is flaky. I can't prove that the pressure box had anything to do with it, but I honestly believe that it did. Therefore I voiced my opinion arrived at from personal experience.



I am still using performance enhancing equipment, just reminding poster of thread that if "you play you pay", reguardless of what the advertisements say.

 

[Matt400]

Take pressure, add a little duration and some timing and you have a winner.

I was hoping to beta test one but never heard back.

 

[Matt400]

The second is mostly timing and duration with a little fuel pressure.

What brands fall in that category?

 

[JVolpe]

From talking with Edge and TST Products the Edge Juice and TST PowerMaxCR are both in this category, I am sure that some/most others making performance programmers/boxes are using this type of programming instead of only fuel pressure and boost fooling, but there are boxes out there that use only fuel pressure and boost fooling. I know I had one.



Like I said I do not knock any manufacturer and have read good things about a number of others also, just have not personnally talked to others.



PS: I have to add that the pressure box I had definitely produced the additional power it advertised. I just was afraid of how it did it.

 

[Matt400]

From talking with Edge and TST Products the Edge Juice and TST PowerMaxCR are both in this category

Interesting, I thought the Juice was pressure & timing and TST was duration only.

 

[JCleary]

Interesting, I thought the Juice was pressure & timing and TST was duration only.

TST is timing/duration only. You can add an EZ or something comparable to get pressure, but it is not necessary. The TST PMCR will give you all the fuel the CP3 has to give.

 

[Matt400]

TST is timing/duration only.

Good to know, I thought they just lengthened the shot but if its timing also then they probably start it sooner also. Theory wise the TST with timing should run cooler than a VA C3. 2 providing both were set to the same power level I would think.

 

[DLeno]

Joe and I will clarify the rail pressure question a bit more clearly in TDR issue #48. Issue #47 didn't come out as we intended.



A rail pressure increase from 23,500 to 26,000 is only 10%. Moderate pressure boxes like the EZ appear to raise rail pressure to figures below 28,000.



if you are getting 28,000 PSI from the data link, remember that that does not mean such pressures are actually achieved. The downloader uses very mild pressure fooling to elevate pressure. commanded pressure may likely be higher than actual. I don't remember exactly, but I thought the downloader pushed rail pressure to the sub-40 HP region. I would have thought it could do that without pressure fooling, and that commanded pressure would be similar to actual in that case. So I dont' really understand the 28,000 commanded figure, except that (again) you really don't know what was actually achieved in the rail unless you measure it. thats what I did in TDR issue #47, but found that the measurement limit was about 26,000 PSI.



Doug

 

[Matt400]

Good point Doug, The folks at TS had me worried with their pressure numbers but I am beginning to think the pressure numbers given are simply whats commanded in their programming and that actual rail pressures are much lower, especially when factoring the volume of fuel being used at a given commanded pressure. If actual rail pressures were as high as commanded pressures I would think these forums would be flooded with blown off limit valves. Time to hook up a gauge to the high pressure side.