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Compression Vs. Exhaust Brake

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  • thefish
    replied
    Get a Telma and a Jake

    All of our newer engines and trucks are spec'd with both a Jake and a Telma. Both are adjustable, the Jake with a switch and the Telma with a lever. The switch and lever are next to each other on the dash. With both on full, I darn near never used the brakes. In fact, my engine slowed down too fast, so I'd turn the Telma down to 50%. It uses less juice then, saving some for the Q!

    You can't ever have too much stopping power on a rig, but our engines damn near do. And brake jobs are near non-existent.

    Someone mentioned lag on the Telma shutting off. Something needs adjusting. I haven't had a problem with that yet, and I've driven probably three dozen plus rigs with one.

    Leave a comment:


  • HSFDChief600
    replied
    Well being a truck driver when im not playing Fire Chief, I have found Jake brakes are great. Exhaust brakes will eventually blow out the exhaust gaskets and will not slow the engine as well.

    Leave a comment:


  • flmslayr2
    replied
    Aux Brakes

    Well, Some considerations I'll have on our next fire engine. I found that if you have a transmission retarder, it requires more maintenance on the cooling system (translation-the cooler on the radiator needs to be replaced every year or two, according to the sheets I saw). I haven't used or dealt with a truck with the Thelma Retarder. I've heard that the electrical load can be an issue. As far as the compression or exhaust, I'm a fan of the compression brake. It seems to work better than an exhaust, and you don't have to worry about blowing out gaskets on the exhaust manifold (on our truck, the 3 piece manifold is starting to leak out).

    I have noticed a tendancy for the smaller motors being installed in the larger trucks, due to the higher amount of HP being pumped out. It sames money intially, but for the big trucks, I feel that there isnt enough motor to effectively stop the truck using either an exhaust or compression.

    Just my thoughts.

    Leave a comment:


  • VanIsleEVT
    replied
    NPFD801,

    Everyone's extremely happy with the rigs. I'm still prepping them right now, radios, flashlights, equipment, etc. We'll train on them next month and place them in service at the end of February. I'm leaving for Maui on monday for two weeks so that prolongs things a little.

    I'm specing a Heavy Rescue now and I'll still be using an Allison but because these new Engines have C13's, I may go with a C9 in the Rescue.

    Leave a comment:


  • npfd801
    replied
    I forgot about Cat's new transmissions. I wonder if someone will take the plunge and put one on their new rig...

    How are the new rigs Vanisle?

    Leave a comment:


  • Chief1FF
    replied
    Originally posted by IronsMan53 View Post
    Braaaaaaaaaaaaaaaaaaaaaaaaaaa-tat--tat---tat----tat-----tat------tat

    Enough said!

    Sung in the style of a Detroit 8v92TA with a straight-stack.
    (gotta love those 2 stroke Detroits)
    What he said!

    I prefer the Jake for the simple reason that if needed it can be used on high, med., low depending on road conditions.

    "They" do say that the Telma's are the most effective of the bunch.

    I will say that if you program the Allison transmission with the agressive down shift into the Jake you do not need the brake pedeal either.

    I think it comes down to what you and your department prefer and what works best for your needs.

    Leave a comment:


  • VanIsleEVT
    replied
    Quotes from another magazine.....

    The C9 has been given a larger 9.3-liter displacement to produce ratings of 365- to 425hp with peak torques of 1,250 to 1,350 foot-pounds. The new engine configuration has a dry weight of 1,650 pounds, which makes it about 1,000 pounds lighter than some other engines in this power range.

    To complement the new models, Caterpillar has a new engine brake and two new automatic transmissions. The Cat engine brake is a compression-type brake option that can be specified on the C9 and C13 engines. It meets the NFPA 1901 requirements for auxiliary brakes on apparatus with GVWR of 36,000 pounds or more.

    Leave a comment:


  • resqb
    replied
    One thing I've noticed on the Telma is the lag from when you step on the gas to when the Telma shuts off. It's just around a second, but when you're used to a Jake that instantly shuts off and you have instant throttle, then go to a rig that lags, it's quite an adjustment. The Telma does work extremely well. But as others have mentioned there is a heat issue.

    Leave a comment:


  • fire0099881
    replied
    Originally posted by IronsMan53 View Post
    Braaaaaaaaaaaaaaaaaaaaaaaaaaa-tat--tat---tat----tat-----tat------tat

    Enough said!

    Sung in the style of a Detroit 8v92TA with a straight-stack.
    (gotta love those 2 stroke Detroits)
    Yep that is one of the greatest sounds to hear! I believe the neighboring dept has that engine in their tanker, I am sure HEYVERN will let me know if I am right or not! Our station is about 4-5 miles away from their station and you can hear it leaving there station!

    Leave a comment:


  • IronsMan53
    replied
    Jake Brake

    Braaaaaaaaaaaaaaaaaaaaaaaaaaa-tat--tat---tat----tat-----tat------tat

    Enough said!

    Sung in the style of a Detroit 8v92TA with a straight-stack.
    (gotta love those 2 stroke Detroits)

    Leave a comment:


  • Rescue101
    replied
    CE11 has it about right.Small engines will generally have an exhaust brake,the true"Jake"compression brake is not offered.Nor are exhaust brakes as effective as a compression version.The jury's still out on the Thelmas,some folks love 'em most mechanics hate 'em.Now,like everything else,the rules are changing.As the "mini mouse"cummins(ISC/ISL) gets "pumped up" there may be a change in the future on auxiliary braking systems.Cat is already headed that way.I wouldn't be fearful of "yellow"engines although I do not favor engines under 10 liter for Fire service work REGARDLESS of mfg.That's just my personal preference. We run exclusively ISM Cummins and have had very good service from them sans a couple software issues.T.C.

    Leave a comment:


  • Engine305
    replied
    Cummins

    My Pierce Enforcer being built, is coming with an ISL 400 with a Jacobs Brake and 4 wheel disc brakes. We stayed away from the trans retarder because we were told it would require maint more often with the heat generated and such. Plus with the disc brakes all the way around and 600 gallons of water on board, she should stop just fine.
    The standard on the ISL 400 in a Custom Contender is an exhaust brake.
    The Jake brake option was aprox $ 3,000 more than a exhaust brake and $ 3,500 less than the transmission retarder on the 3500 series Allison transmission.

    Leave a comment:


  • Halligan84
    replied
    I believe the transmission retarders that Allison offered required more maintenance and generated more heat.

    We have had 3 Telmas for the last 12 years, never a problem. We also have 4 wheel abs and disc brakes, if the driver panic stops you better be belted or your launched.

    Leave a comment:


  • Dave1983
    replied
    Our primary reserve engine is a "93 Pierce with a Detroit 450hp and a Telma. The Telma will pretty much stop the rig by itself, and works better for stopping then either of the the engine-type bakes.

    But from what I understand it generates alot of heat and does something to the transmission that requires more frequent service. Im not a mechanic, so I have no idea why, but thats the reason we went away from the Telmas.

    On our new quint with a Detroit 500hp we went with the Jake brake. With our new pumper with a Cummins 370hp, we went with an exhaust brake. Both types work well for the particular size of vehicle. So I guess your answer would be in the size of your rig. The heavier the rig, the more I would lean towards the Jake brake.

    Leave a comment:


  • BCFD25
    replied
    one thing i would seriously consider is how close are the cat and cummins service centers to you. i dont mean truck dealers either. Alot of truck dealerships work on them but many are not true service points i.e. warranty work, specailty tools, and service literature. Also do you have experience with these shops? good or bad?

    i know someone mentioned stay awya from the cats but honestly in 07 its fair game as far as ia m concerned. now cat is gettin away from the huei fuel system in 07 and going to a common rail which is what most are using now anyways. much more efficient, less moving parts, and easier to troubleshoot.

    Take it easy, jon

    p.s.- the reason smaller engines dont have them is because the heads arent big enough to take that kinda torque

    Leave a comment:

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