| Author |
Message |
Matt (Hgtech)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, March 16, 2006 - 10:05 pm: | |
I know this has been discussed on here quiet a bit but I'm going to bring it up again.
I'm debating moving to an air throttle on my 05 Eagle. The factory throttle is linkage driven and is not only stiff - but is starting to get very sluggish - especially when it's cold outside.
My concern is being able to accurately shift gears. I've gotten really accurate IMHO at double clutching with the linkage throttle. It's become something I don't even think about. Guess that happens after 50,000 miles. My concern being that an air throttle will be totally different and I'll have to re-learn how to drive.
Anyways, I'd like to hear results from any of you guys that have moved from Linkage to an Air Throttle - Particularly on an Eagle. Engine response, learning curve, how it's different as far as driving and shifting.
Also, when you move to an air throttle - what happens to the high idle? Is there some way to get it working again.
I'm looking at the air throttle kit for the 8v71 Tom Hall has for sale for about $475.00. Does anyone have any experience with this kit.
Thanks!!!
Matt
1979 Silver Eagle Model 05 |
vern rainville
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, March 17, 2006 - 8:16 am: | |
Hi Matt, I have a Wiiliams air throttle that I bought from "ronthebusnut". I have an 01 Eagle with a 8V71. It had a standard tranny, but I changed it to an HT-740. As far as putting it in a standard tranny set up, I can not answer that.As far as the automatic goes, I can tell you that there is "a little" hesitation to rev up the motor, although not enough to be of concern. You are right on to ask if anyone with a standard can answer this.The "action" of the air throttle is quite nice, which translate to a very light pedal.As far as the high idle, haven't got there yet, but I would think that is the least of concerns. Hope this helps. Vern (in RI) |
John MC9
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, March 17, 2006 - 8:39 am: | |
I have an air throttle on my MC9 with a 740 auto. I hate it.
I cannot fathom using one with a standard. It's very difficult
to apply the proper foot pressure, to produce an exact rpm.
If it weren't for the rust factor, I would've bought an old Eagle
with a standard instead (my true preference). If I had, I would
repair the OE throttle if necessary, at any cost, rather than
even think about changing to an air throttle.. |
Robert J. Wies (Ncbob)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, March 17, 2006 - 11:35 am: | |
Has anyone considered using a Morse (Teleflex) Marine
cable for the throttle cable? I know they come in lengths up to 45' and the ends are sealed w/boots.
Now whether the application is 'push to open' or 'pull to open' one might have to incorporate the use of a bellcrank w/arms of different lengths to attain the proper ratio.
Just a thought...... |
Pat Bartlett (Muddog16)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, March 18, 2006 - 8:34 am: | |
Hey John, did you install your air throttle, or was is OEM? The reason I am asking, is there has to be either a air leak or incorrect installation. When I was working as a Instrumentation tech, pneumatics was considered old school in the industry(refineries, chemical plants, power plants) air signals are just as reliable as electrical or mechanical devices performing the same function. My Prevost has a mechanical throttle, at times I would really have to stand on the throttle.....that said, I'll tell you why I am changing to a air throttle.
First reason, is I'm to old to stand on the throttle all day.
Second reason, is I plan to eventually install cruise control.
Third reason, it is in my opinion that with the level that I have stripped my bus going back with new air lines insures a new system.
Fourth reason, I have the experience working with pneumatics to feel comfortable with this installation.
Now some items that you might check on your system. Is there a pressure regulator on the feed supply to your existing air throttle? Is the line size to your air throttle properly sized? Talking with Tom Hall, he brought up a point about correctly sizing air lines, air lines are sized by the inside diameter (I.D.) and not the outside diameter(O.D.), What appears to be a 3/8" line (O.D.) diameter tube might actually be a 1/4" line (I.D.) diameter.
If your throttle seems sluggish, this could be an air leak, worn throttle valve, or a incorrectly sized line. This could also be a faulty relay valve at the engine, worn diaphram, or even loose connection. If the line is undersized it might really affect how sensitive your throttle could be. Installing the treadle valve(air throttle)with out a pressure regulator could also limit or restrict not only the air pressure but air volumn. Which would make your system react in the manner you describe.
The reason these bus companies use air systems is cost, and reliablity. What you have to remember is that again 20 + year old coaches need TLC.
I saw where Luke was talking about an alcohol air drying system for winter driving, if you live in the north, my opinion is that this is a must for a reliable system. Also you need to dump and bleed your system after every use, without exception, that will eliminate moisture in the air from sitting in your lines and causing corrosion, which will eventually become the particles that clog and plug your system up....that is a critical point!....
I know there are many opinions that differ with what I have just said, but again its your choice.
I hope you didn't mind my boring post, but it could possibly help someone who needs it.
Have a great day! Pat |
John MC9
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, March 18, 2006 - 10:21 am: | |
Pat -
Not now, and never will be "boring". Any and all input and
comments are always welcomed reading (by me, anyway).
My bus's engine had been changed (from what, is a mystery)
and presently has a 6v92 with "low miles". It was also changed
from a standard to an automatic (740), and many other
modifications, changes, and cobbed up repairs made during
it's life in service. I bought it "in service", and was encouraged
to keep it in service... I declined (sounded like good money, tho).
Anyway..... Your points are well considered. The air throttle
does not appear to be original, since the hole under the pedal,
and the mechanical leftovers in the tire cage give indication
that it was originally a mechanical throttle.
I have no clue regarding the "proper size" of piping, since the
job was done in what appears to be the proper manner at the
ends I can see. What's between here and there, is a mystery.
The throttle works fine, but from what I can remember of
driving buses with air throttles, the accelerator is not as
controllable as a mechanical system.
There's just an inherent delay, and an inherent surge, that
goes with air controlled systems. I don't know any way
around that. Regulating the pressure won't matter all that much,
since that's what the pedal does.. And the fluctuating air
pressure of the entire air system, doesn't seem to matter
as far as the controllability of the air throttle
There's a certain amount of compression that takes place
prior to the air doing it's thing at the far end..
Sure, my system has air leaks to be tended to, but I sincerely
doubt that's the issue with mine. It's just tough to use the
accelerator to any exacting degree.
It's ok for an automatic transmission, but I wouldn't want it
on a standard. Or at least that's my opinion.... If someone's
using an air throttle on a standard and loves shifting with it...
well.... ok. But will someone like Matt like it?
Convince me. If it should be better than I describe mine,
and I'll work to fix it. But the guys at the local bus garage
all said what I did.... rather not have it on a standard. The
garage now has all automatics anyway. |
Matt (Hgtech)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, March 18, 2006 - 10:44 am: | |
Well, I'm not really sure what to do as far as the air throttle goes. You guys have brought up some interesting points (both good and bad). My biggest issues with the mechanical throttle are it being very sluggish when it's cold out (to the point I have to shift gears totally different) and my foot/back wearing out. My bus is a tour bus for a band and 16+ hours of driving a day isn't uncommon. While I like the responsiveness of the mechanical throttle (when it's warm out), I'd just about trade that in for a lack of cramps in my foot/back.
I'm thinking about ordering the air throttle and trying it, but leaving the mechanical linkage in place in case I decided to go back to it.
Matt
1979 Silver Eagle Model 05 |
Ross Carlisle (Rrc62)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, March 18, 2006 - 10:36 pm: | |
Has anyone ever heard of an electric throttle? Something like a pot under the pedal (sender) and a servo on the engine. Seems like you'd get more precise throttle control. You could use a linear actuator with a position feedback as a servo. All you'd need then is a servo controller. |
Richard Bowyer (Drivingmisslazy)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, March 19, 2006 - 9:59 am: | |
Matt, it sounds to me like a good cleaning/lubricating/overhaul of your mechanical throttle system would be much less expensive and give you much better control than an air throttle would. In my experience, air throttles are good for automatic transmissions only.
Richard |
Syd Pygott (Sydstoy)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, March 19, 2006 - 6:08 pm: | |
The new transit buses have electric throttles. The power pedal moves a reostat that tells the computer that tells the engine the driver wants to go.
Syd |
John MC9
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, March 19, 2006 - 9:27 pm: | |
"The power pedal moves a reostat that tells the computer that
tells the engine the driver wants to go."
Oh, yuck. Is this what it's coming to? |
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