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Author Topic: Telma retarder report after 28 hours of driving with it  (Read 3895 times)
boogiethecat
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« on: September 14, 2006, 09:38:28 PM »

Well, I got the Bluebird roof raised, interior "well enough along", tanks and support stuff finished & working and the engine running perfectly, and took it to Burning Man  along with my Crown.  The Crown has a cummins 220 with Jakes, and the Bluebird- the subject of this report, has the Telma retarder.

We went up hwy 395 from San Diego to Reno & back, and encountered lots of 6-7% grades along the way- the Cajon pass being just one of many.
The Crown and the Bluebird were both loaded close to 27k, so both busses had about the same mass. 

Coming down the grades, it was super obvious that the Telma WAY outperformed the Jakes.  My Crown's Jakes have 3 retarding selections, and the Telma has four... coming down the Cajon pass for instance, the Jakes were all the way on and I had to use the brakes a few times.  At the same speed following me was the Bluebird, which never used higher than position 2 to maintain safe speeds... even in position 2 the Telma would slow it down too much so the driver ( a friend) had to keep switching between pos. 1 and pos. 2. MUCH more retarding power than needed.

When we got home I wanted to see how it would do with even more mass, so we hitched my 5000 pound generator trailer up to it and took it out on I-56 which has a nice 6% grade up one side and around 7% back down the other... again position 2 was too much, and if we switched it to position 4 at 70 MPH it was only a matter of seconds before we were going 30 !!

I rigged the Telma so it also activates (via sequentially adjusted air pressure switches) when the brakes are applied, meaning that it does most of the vehicles braking before the brake shoes ever hit the drums, and I designed a little circuit that hooks to a cruze control sensor that turns the Telma off when the vehicle comes to a stop, and turns the engine fan clutch on at the same time ( a  free little bonus for me).
The Telma in this mode takes care of 90% of the vehicle's braking even in city environments... in fact I'd feel safe if the service brakes failed, as the Telma will take you almost to a stop before the service brakes even engage!! It's quite a nifty system, saves brake pads like nothing else can.

Bottom line, the Telma is even more amazing than I ever thought it would be, and I highly recommend the things.  Now I want to toss my Jakes and get one for the Crown although it would have to be a "focal" type due to my short driveshaft.  Hard to come by...

cheerio
Gary
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1962 Crown
San Diego, Ca
TomC
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« Reply #1 on: September 14, 2006, 10:39:50 PM »

You can mount the Telma either at the end of the transmission, in the middle of the drive train, or on the rear differential (which I wouldn't suggest since then you'd have all that extra unsprung weight-and if you have air suspension, can't mount it on the differential because of the tremendous heat produced could pop an air bag).  I am specing another truck for one of my customers that uses Telmas exclusively.  The proposal to install on a new truck by Fontaine near our North Carolina Freightliner plant is $10,800.00!  So finding a used one would be advantageous.  Good Luck, TomC
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Tom & Donna Christman. '77 AMGeneral 10240B; 8V-71TATAIC V730.
belfert
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« Reply #2 on: September 15, 2006, 04:57:33 AM »

Now I wish my Dina had a Telma instead of the Jake brake.  They were offered with a Telma, Jake, or no engine brake.

The biggest problem I see with Jakes is so many towns restricting them.

Brian Elfert
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rayshound
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« Reply #3 on: September 15, 2006, 06:47:55 AM »

I'm still looking for suggestions on the best way to hook mine up. I have the HTB-748 ATEC coupled to a 12.7L Series 60 with 3 stage jakes. I'm still running wires etc. the engine & trans is coupled. When it gets time to go to Steward & Stevenson (detroit dealer) I need to get my ddec 4 some of the data base items reprogramed as the engine was out of a truck. Looking at my manual one of the items asks for jakes y or n and I want to hook them both up. Not sure how to fool ddec as yet to use eigther also need a plan to hook up the retarder to the brake system as I got no controls with the purchase of the trans. I understand a leaver or 3 pressure switches is used to modulate the air signal to the retarder air line. Any suggestions, Thanks Ray
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boogiethecat
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« Reply #4 on: September 15, 2006, 07:09:10 AM »

Ray, just forget the jakes and hook up the Telma on it's own- I doubt you'll ever need both if the Telma is sized right for your bus.. 
  There's no need to try to hook it into the DDEC system- Using the air switches and a 4 position driver switch, that's all you need.  One thing you DO need with the Telma is a way to make sure it gets turned off when the vehicle comes to a stop- it uses a lot of electricity (160 amps when fully on) and will burn itself up with no movement.
I have an extra set of air switches I can sell you if you email me privately, and if you know an electronic geek I can provide a circuit schematic and parts list for the auto-turnoff although I don't want to build any more of them.  Do you have the relay control box for the thing?
Gary
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1962 Crown
San Diego, Ca
RJ
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« Reply #5 on: September 15, 2006, 08:46:53 AM »




The biggest problem I see with Jakes is so many towns restricting them.




The "biggest problem" is really a non-problem for bus owners, and certainly not something to fret over.

If you keep the stock exhaust system w/ it's muffler, the jake is hardly noticeable in a bus.

You shouldn't have the jake turned on while driving around town anyway - let the renegade 18-wheeler jockeys take the heat.

Concentrate on the important stuff.

FWIW. . .
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RJ Long
PD4106-2784 No More
Fresno CA
rayshound
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« Reply #6 on: September 15, 2006, 09:01:47 AM »

Gary (Boogiethecat), Thanks, my transmission is a HTB 748 ATEC which is a Allision with a factory Hyd. retarder. The ATEC part is the electric controls for the trans. and I have them, the brain, remote relays, harness and push button selector. it looks like the retarder part just uses a single 3/8" air line more than likely comming as an air siginal from the out put from the brake pedal.
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belfert
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« Reply #7 on: September 15, 2006, 09:09:58 AM »




The biggest problem I see with Jakes is so many towns restricting them.




The "biggest problem" is really a non-problem for bus owners, and certainly not something to fret over.

If you keep the stock exhaust system w/ it's muffler, the jake is hardly noticeable in a bus.

I call it a problem when engine braking is prohibited on places like I-80 coming into Salt Lake City.  There is a fairly steep grade coming into town from the east for 10 or 15 miles where engine braking is prohibited.

I do have the stock exhaust.  The Jake was really loud when the exhaust pipe was broke in half and I didn't know it.

Brian Elfert
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Busted Knuckle
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« Reply #8 on: September 15, 2006, 12:06:38 PM »

I call it a problem when engine braking is prohibited on places like I-80 coming into Salt Lake City.  There is a fairly steep grade coming into town from the east for 10 or 15 miles where engine braking is prohibited.

I do have the stock exhaust.  The Jake was really loud when the exhaust pipe was broke in half and I didn't know it.
Brian Elfert

Brian as I've said before, IGNOR THAT SIGN! Use yer Jake Brake!!! As Russ points out (an I have in the past)they are trying to keep "outlaw chicken Haulers" like I used to be from coming thru there and throwing the JAKES on with straight pipes right next to the Country Club & Golf Course!
It's a safety device! And the Judge really gets annoyed at the cops who right tickets to truckers who come back to court(or have a Lawyer represent them) & point out that they are "outlawing a safety device" I know the Lawyer that went for me all 3 times, got a kick out of the Judge when he was in front of him representing me and several others and asked "since when and where in the constitution does it say operators of heavy vehicles shall risk their lives, by NOT BEING ALLOWED TO USE a safety device installed on their trucks when coming down the mountain next to the County Countr0y Club?". He said the Judge  called a 5 min. recess called the cop, court clerk, bailif, lawyer & recorder in his chambers !  Once everyone was behind closed doors he asked the Lawyer "are you serious?"  To which he replied "yes sir!" Then the judge had the clerk make a couple of calls, and asked the cop who instructed him to "enforce this silly ordenance" and the cop said "my capton sir, but it came down from the Mayor! I was told SIR". When the clerk came back in she and the Judge talked a moment and the Judge ended the recess. Once back in the court room the Judge asked if anyone else was there for the same offense, to which about 8 or 9 truckers stood up. The judge called the all to the front had the bailif & clerk check their cases and told them all they were dismissed! He then told the cop "don't waste my or the tax payers time & $ on this again! Do you understand me?" My lawyer said he almost busted out loud when the cop answered "i'm SORRY SIR, but I have to follow orders" and the Judge stopped him before he could finish and asked him "if he understood what it meant to be held in contempt of court?" The officer quietly said "yes" and the Judge said "I pressume we have an understanding then?" to which the cop again quietly said yes!

 So just because these BOZO's put those signs up don't mean they are legal, and if they are inforced they are easily beaten! (as are many tickets issued, but they count on you just paying the fine and forgetting it!)

Now I know everyones gonna say I don't have the time to go fight a ticket I didn't deserve in the first place! I know, when I was trucking I didn't either! That's why I had a prepaid legal service that would fight tickets for me for an annual membership fee! And a lot of times I'd get them canceled or reduced myself by phone! Don't let them take advantage of you "just cause yer just pass'n thru!"

But in reality I wouldn't worry about using a Jake ANYWHERE if either of my buses had one! BK  Grin
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Busted Knuckle aka Bryce Gaston
KY Lakeside Travel's Busted Knuckle Garage
Huntingdon, TN 12 minutes N of I-40 @ exit 108
www.kylakesidetravel.net

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TomC
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« Reply #9 on: September 15, 2006, 01:10:18 PM »

Ray- I want to get something straight.  The Telma retarder is totally different than the hydraulic retarder thats on the HTB 748.  The Telma, being basically an electric motor in reverse, works very well on long down hills since it has built in cooling fan in the rotor, and as long as your batteries can keep up, all the better.  On the other hand, the Allison hydraulic retarder is NOT made to be used on long down hills continuously.  Basically, the hydraulica retarder is a torque converter in reverse that uses the oil in between two wheels with paddels that the oil creates the drag.  All this power dissappation creates a tremendous amount of heat which builds up quickly in the retarder.  So coming down a long grade, you have to keep an eye on the temp gauge and dump the retarder every so often so it can refill with cooled down oil.  The hydraulic retarder works great around town as a supplement to braking-you can hear them on transits in that just before the bus comes to a stop you can here the air release of the retarder turning off, or the same every time the driver releases the brakes.  Bottom line, if you have a Telma electric retarder, you can use it for all your retarding situations.  If you have the Allison with the hydraulic retarder, think of it as a brake supplement in stop and go traffic with long down hills better suited for Jake brakes.  What's nice about the Jake brake, since it is absorbing the power, it too creates heat.  So on long downhills, the Jake will help to keep the engine heat up so the engine isn't too cooled off when the power is reapplied.  This is usually only an issue in very cold winter type driving.  Good Luck, TomC
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Tom & Donna Christman. '77 AMGeneral 10240B; 8V-71TATAIC V730.
Clarke Echols
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« Reply #10 on: September 15, 2006, 05:34:49 PM »

I am very familiar with the steep grade down Parley's Canyon on I-80 west-bound into Salt Lake City and
the sign prohibiting engine brakes.  I have also noticed many towns and cities are changing their signs
from "Engine brakes prohibited" to "Engine brake mufflers required".  There are a lot of truckers who
like their big 6- or 8-cylinder engines to belch noise out the pipes to "impress' their buddies at how much
noise they can make.  It's not unlike the Harley crowd that roar past my home with pipes so loud it
hurts my ears.  When I complained to a biker at a local Harley dealership, he explained that in our town
the fine is $1000 for loud pipes on a hog, and it's at the discretion of the cop what constitutes "too loud".

Several years ago, the local ready-mix concrete company's 18-wheeler (a Kenworth) that hauled dry
powder cement from a plant south of us to their batch plant had jakes installed.  It also had engine
mufflers installed.  Even under full throttle, it was impressively quiet and smooth-sounding.  Coming
back with a load, the jakes were full on as the driver went by, yet it was impressively quiet.  No
reasonable person would ever complain.  But jakes on an unmuffled engine are a different matter
entirely.

So if you're running straight pipes, skip the jakes.  If you have working mufflers installed, use them all
you want.  You won't make enough noise for the cops to even notice.  And I can understand why
the locals along I-80 in SLC complain.  That grade extends into the populated areas.

On the other hand, the locals seem to be completely ignorant of the meaning of "Speed Limit".  If
you drive the limit, they get upset at you holding them back in traffic.  Not unlike Denver.  They
should have left the speed limit on I-25 north and south of Denver at no more than 70 as when the
road was built, not 75 like it is now.  People think they need to go 80-85, expecting the cops to
leave them alone as long as they're not more than 8 mph above the limit.  But watch out.  Last
Saturday night, the state troopers were out in force north of Denver stopping speeders and
drinkers.  One driver was undergoing a sobriety test as we went by.  In about 5 miles, we saw at
least 5 troopers at the side of the road writing tickets.

If you get away from rush hour when traffic thins out, the speeds also go down on I-25.  At 8:30 AM,
most are running at least 75 mph.  90 minutes later they're doing 60-65.  Why?  They were late to
work and in a hurry.  In mid-morning, they're on the company clock and not so rushed.  Says a lot
about the working class, eh? Smiley

Clarke
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rayshound
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« Reply #11 on: September 15, 2006, 08:05:10 PM »

Thanks Tom, I now understand and appreciate the info. I'm going to use them both. But I'm back to figuring out how to hook  them both up.  Ray
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TomC
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« Reply #12 on: September 15, 2006, 11:14:51 PM »

Ray- as said before, make sure you hook both up so only one can be used at a time.  The best way I can think of is to use a three position toggle that is on-off-on.  Good Luck, TomC
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Tom & Donna Christman. '77 AMGeneral 10240B; 8V-71TATAIC V730.
Len Silva
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« Reply #13 on: September 16, 2006, 05:42:58 AM »

[Brian as I've said before, IGNOR THAT SIGN! Use yer Jake Brake!!! As Russ points out (an I have in the past)they are trying to keep "outlaw chicken Haulers" like I used to be from coming thru there and throwing the JAKES on with straight pipes right next to the Country Club & Golf Course!
It's a safety device! And the Judge really gets annoyed at the cops who right tickets to truckers who come back to court(or have a Lawyer represent them) & point out that they are "outlawing a safety device" I know the Lawyer that went for me all 3 times, got a kick out of the Judge when he was in front of him representing me and several others and asked "since when and where in the constitution does it say operators of heavy vehicles shall risk their lives, by NOT BEING ALLOWED TO USE a safety device installed on their trucks when coming down the mountain next to the County Countr0y Club?". He said the Judge  called a 5 min. recess called the cop, court clerk, bailif, lawyer & recorder in his chambers !  Once everyone was behind closed doors he asked the Lawyer "are you serious?"  To which he replied "yes sir!" Then the judge had the clerk make a couple of calls, and asked the cop who instructed him to "enforce this silly ordenance" and the cop said "my capton sir, but it came down from the Mayor! I was told SIR". When the clerk came back in she and the Judge talked a moment and the Judge ended the recess. Once back in the court room the Judge asked if anyone else was there for the same offense, to which about 8 or 9 truckers stood up. The judge called the all to the front had the bailif & clerk check their cases and told them all they were dismissed! He then told the cop "don't waste my or the tax payers time & $ on this again! Do you understand me?" My lawyer said he almost busted out loud when the cop answered "i'm SORRY SIR, but I have to follow orders" and the Judge stopped him before he could finish and asked him "if he understood what it meant to be held in contempt of court?" The officer quietly said "yes" and the Judge said "I pressume we have an understanding then?" to which the cop again quietly said yes!

 So just because these BOZO's put those signs up don't mean they are legal, and if they are inforced they are easily beaten! (as are many tickets issued, but they count on you just paying the fine and forgetting it!)

Now I know everyones gonna say I don't have the time to go fight a ticket I didn't deserve in the first place! I know, when I was trucking I didn't either! That's why I had a prepaid legal service that would fight tickets for me for an annual membership fee! And a lot of times I'd get them canceled or reduced myself by phone! Don't let them take advantage of you "just cause yer just pass'n thru!"

But in reality I wouldn't worry about using a Jake ANYWHERE if either of my buses had one! BK  Grin

On the other hand, in my little Florida town, flat as a pancake with a twenty mph speed limit, the log haulers love to drive through town in a low  gear with the Jakes on, trying to see if they can break any store front windows.  The town has posted engine braking signs and I think a driver here would have a difficult time with the safety argument.

Len
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« Reply #14 on: September 16, 2006, 03:41:03 PM »

Busted Knuckle is correct!!If you take the time to read the D.O.T. comercial drivers manual you will see it states that a "Jake Brake" is a safety device ! you cannot be  bared from using it. On the other hand if you don't have a muffler you could get a ticket for the noise !
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boogiethecat
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« Reply #15 on: September 16, 2006, 05:56:09 PM »

...back to Telma... oh yeah, this thread got hijacked!!  Smiley
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1962 Crown
San Diego, Ca
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