Has anybody experimented with one of Pac Brakes new style PRXB Exhaust brakes on a multifuel? I have a 4" PRXB Brake off a 2nd gen 24 valve dodge. Mounting will be pretty easy im mainly concerned with how much back pressure these engines can handle. The motor these brakes were designed to work on have 60 lb valve springs from the factory. Does anybody know what valve springs are in a multifuel?
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Pac Exhaust Brake on a Multifuel
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nk14zp
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http://www.steelsoldiers.com/deuce/3255-deuce-exhaust-brake-details.html
Also search his posts for more info. I hope this helps.
Also search his posts for more info. I hope this helps.
I saw that thread before i posted mine but not a whole lot of usefull information there.
To the point around the day to day chit chat that clogs up threads...
-What kind of backpressure can these engines handle?
-Has anybody ran a brake that created enough backpressure to cause a valve to float into a piston (similar to the 5.9 series dodges)?
-There is a 30psi backpressure number floating around throughout my searches.... where is it comming from?
-WHAT SIZE VALVE SPRINGS ARE IN A MULTI FUEL ?
Thanks for the help!
To the point around the day to day chit chat that clogs up threads...
-What kind of backpressure can these engines handle?
-Has anybody ran a brake that created enough backpressure to cause a valve to float into a piston (similar to the 5.9 series dodges)?
-There is a 30psi backpressure number floating around throughout my searches.... where is it comming from?
-WHAT SIZE VALVE SPRINGS ARE IN A MULTI FUEL ?
Thanks for the help!
if you really want to find out how strong your valves currently are you'll have to take them out and test, or remove the exhaust manifold, make a flat plate to cover a single exhaust port and pressurize till it opens the valve.
i doubt there are any hard numbers already available for this.
I have plans to add an exhaust brake to my deuce but did not find much information aside from the hands on experimentation.
i doubt there are any hard numbers already available for this.
I have plans to add an exhaust brake to my deuce but did not find much information aside from the hands on experimentation.
quickfarms
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Have you looked at their website
They have downloads that cover most civilian engines.
If the multifuel is not listed I would contact them directly.
I think 30 lbs is used on engines with no other information or weak valve springs.
They have downloads that cover most civilian engines.
If the multifuel is not listed I would contact them directly.
I think 30 lbs is used on engines with no other information or weak valve springs.
Im just hoping for someone to chime in who is ACTUALLY running a brake on a multifuel and what setup/ backpressure specs they have. There are lots of cheap exhaust brakes that are not very effective but the brake i have is most likely capable of internal valvetrain damage.
Im thinking about running it on my non-turbo multifuel project in case it goes BAM then i have a reason to swap in the turbo motor.
Im thinking about running it on my non-turbo multifuel project in case it goes BAM then i have a reason to swap in the turbo motor.
820jeep
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Please let us know what you find out. I am hoping for no BAM!
brianp454
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More Multifuel exhaust brake discussion
Hey guys, this thread has gone stale and I hope to revive it. I’ll be sending PM’s to some folks that posted here and ask that they reply to the thread (vs PM) so everyone can see it. I’m searching posts, but haven’t quite found what I’m looking for.
I think there’s a fair amount of interest in adding an exhaust brake to the M35A2 trucks with multifuel engines (saving wear on service brakes and providing additional braking capability on grades). I think the potential interest in an exhaust brake for the 800 series truck is likely lower than M35A2’s based on the fact that full Jake brakes are available for the NHC-250 engines and the Canadian trucks have Jakes anyway.
From my understanding of exhaust brakes there is a finite limit to the amount of back pressure the brake can generate based on the limitation of the exhaust valves floating (i.e. not returning to their seat or following the intended opening and closing lift profile). This is different for each engine design, operating conditions (especially RPM), etc. As a result, the back pressure is limited by a method such as keeping the butterfly valve cracked a bit, orifice(s) in the butterfly valve, a bypass valve (like a waste gate) or other pressure-sensitive valve arrangement to limit backpressure to safe operating levels. I think the setting for each particular engine\truck\etc. is typically determined empirically, i.e. experimentation with a particular setup. I imagine that PACBRAKE and other get their hands on a new truck and take measurements, then design their brake not to exceed that backpressure level. Does anyone here have experience with this sort of thing, especially for multifuels?
I put in a call to PACBRAKE and have a list of things to follow up with them. I'm hoping the replies here in the coming days help me with getting more answers.
Would anyone please PM me all of the numbers and markings on their multifuel turbo?
Hey guys, this thread has gone stale and I hope to revive it. I’ll be sending PM’s to some folks that posted here and ask that they reply to the thread (vs PM) so everyone can see it. I’m searching posts, but haven’t quite found what I’m looking for.
I think there’s a fair amount of interest in adding an exhaust brake to the M35A2 trucks with multifuel engines (saving wear on service brakes and providing additional braking capability on grades). I think the potential interest in an exhaust brake for the 800 series truck is likely lower than M35A2’s based on the fact that full Jake brakes are available for the NHC-250 engines and the Canadian trucks have Jakes anyway.
From my understanding of exhaust brakes there is a finite limit to the amount of back pressure the brake can generate based on the limitation of the exhaust valves floating (i.e. not returning to their seat or following the intended opening and closing lift profile). This is different for each engine design, operating conditions (especially RPM), etc. As a result, the back pressure is limited by a method such as keeping the butterfly valve cracked a bit, orifice(s) in the butterfly valve, a bypass valve (like a waste gate) or other pressure-sensitive valve arrangement to limit backpressure to safe operating levels. I think the setting for each particular engine\truck\etc. is typically determined empirically, i.e. experimentation with a particular setup. I imagine that PACBRAKE and other get their hands on a new truck and take measurements, then design their brake not to exceed that backpressure level. Does anyone here have experience with this sort of thing, especially for multifuels?
I put in a call to PACBRAKE and have a list of things to follow up with them. I'm hoping the replies here in the coming days help me with getting more answers.
Would anyone please PM me all of the numbers and markings on their multifuel turbo?
Last edited:
brianp454
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Thanks for sharing. There are two threads on a similar subject line.
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Never too late to revive an old thread. Perhaps there is some newer info that can be shared. Someone MUST have put a Pacbrake in by now!!
gimpyrobb
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I have some valve springs I could send someone if they wanted to test the pressure. I have no way of doing that.
gimpyrobb
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PM sent.
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To the top any updates on this!?
64440
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So I’m one more guy curious about this.... anybody done it yet?
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Deuce exhaust brake details
A question came up on the ex-brake. Here are some detail images. The exhaust brake is useful when going downhill with a heavy load. It helps slow you down (it's an engine brake) and works best when the rpm is high. The back pressure is multiplied by the rpm for the braking horsepower. Back...
www.steelsoldiers.com
brianp454
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They short version is YES. Look for other threads here. I have one and will install it when I get time