| Author | Message | ||
| Scott Crosby (Scott_crosby)
Registered Member Username: Scott_crosby Post Number: 118 Registered: 12-2011 Posted From: 166.147.72.149  Rating: N/A |
The mecanIc told me today that he removed a throttle retarder from my engine. He said it's not supposed to be there on a non turbo. True? False? I'm not knowledgeable about these engines at all. I was just concerned that something is getting removed that was supposed tonbe there. 6v71 with blower | ||
| Brian Evans (Bevans6)
Registered Member Username: Bevans6 Post Number: 133 Registered: 5-2009 Posted From: 207.164.79.25 Rating: N/A |
Most naturally aspirated engines don't need a throttle delay, but there may be one for economy reasons. Turbo engines have them to let the turbo spool up a bit before the fuel is fully added. I can't see why taking it off would be a bad thing for performance. You may get a bit more smoke on initial acceleration. My 8V71T has one, my 8V71N did not. Brian | ||
| Brian Evans (Bevans6)
Registered Member Username: Bevans6 Post Number: 134 Registered: 5-2009 Posted From: 207.164.79.25 Rating: N/A |
More: My manual suggests they were more used on city coach engines, so that's what you have, I think. They are to improve economy and reduce smoke on acceleration, per the book. Brian | ||
| Luvrbus (Luvrbus)
Registered Member Username: Luvrbus Post Number: 1409 Registered: 8-2006 Posted From: 24.251.184.12 Rating: N/A |
They were for emission proposes only on the 71 series and 92 series a Cally thing lol be thankful he threw it away you see those on 71 N/A engines what type did you have ? a throttle delay or a fuel modulator (Message edited by luvrbus on February 23, 2012) (Message edited by luvrbus on February 23, 2012) | ||
| Brian Evans (Bevans6)
Registered Member Username: Bevans6 Post Number: 135 Registered: 5-2009 Posted From: 207.164.79.25 Rating: N/A |
Clifford, do you use them on turbo engines, like my 8V71T with N80 injectors? Brian | ||
| Luvrbus (Luvrbus)
Registered Member Username: Luvrbus Post Number: 1410 Registered: 8-2006 Posted From: 24.251.184.12 Rating: N/A |
I always remove those Brian makes for slow start at a light was a good idea on paper | ||
| Brian Evans (Bevans6)
Registered Member Username: Bevans6 Post Number: 136 Registered: 5-2009 Posted From: 207.164.79.25 Rating: N/A |
Good, solves the need to adjust it! Brian | ||
| Scott Crosby (Scott_crosby)
Registered Member Username: Scott_crosby Post Number: 119 Registered: 12-2011 Posted From: 166.147.104.157 Rating: N/A |
Yes mine was a city bus and in California... Maybe I should look for a catalytic converter hidden in there too  I don't know what kind but I'll ask. I'm guessing it's mechanical something or another since there is only one wire running to that engine and it's a ground. Just kidding not really but close to it and it's nice working on a vehicle when only 1% of the wiring and electronics has something to do with it running or not. | ||
| Brandon M (Brandon314159)
Registered Member Username: Brandon314159 Post Number: 79 Registered: 3-2011 Posted From: 173.8.221.225  Rating: N/A |
My '55 TDH-4512 had one of the fuel delay deals under the valve cover (the small piston in a cup filled w/ oil and a small restriction). I left it off when I installed the 4-valve head + jake brakes. Little more snappier. Talking with the guys that used to do a lot of work for MARTA (Pioneer Transmission) Gary indicated that in some setups you could knock people right out of their seats if you snapped the throttle down without this little modulator deal. Gotta keep the glasses on the old ladies and people in their seats | ||
| Scott Crosby (Scott_crosby)
Registered Member Username: Scott_crosby Post Number: 122 Registered: 12-2011 Posted From: 99.100.88.196 Rating: N/A |
Huge difference in acceleration from a stop. It's amazing. I didn't ask him because he was not being very nice and every question I asked even about break in routine or anything it was like I was an inconveniencing him big time. They just wanted me to pay, sign off and leave with no instructions what so ever. I am extremely ticked off right now so I won't go into it more than that. | ||
| Dave Walker (Chrome_dome)
Registered Member Username: Chrome_dome Post Number: 463 Registered: 3-2010 Posted From: 75.247.101.95  Rating: N/A |
So pictures maybe, I have a 6V-71 do I have one. Where is it located and is there anything to be hooked up differently if i take it off. Does it show in DA BOOK Dave5Cs | ||
| Brian Evans (Bevans6)
Registered Member Username: Bevans6 Post Number: 137 Registered: 5-2009 Posted From: 207.164.79.52 Rating: N/A |
It's shown in the tune-up section of the Detroit Diesel V71 Highway Vehicle Service Manual, section 14.14 page 3. Not sure what book you mean by DA BOOK, I have manuals for the engine and for my bus, and parts manual for my bus, this particular assembly is only in the engine manual since the bus didn't come with it stock. If you have one, it will be part of the left side rocker post for the front cylinder on the left hand bank of the engine, looking at it from the front. You can't miss it! Brian | ||
| Dave Walker (Chrome_dome)
Registered Member Username: Chrome_dome Post Number: 466 Registered: 3-2010 Posted From: 75.247.101.95 Rating: N/A |
Thanks Brian, yes i have all those manuals also so will look in the engine manual. Dave5Cs | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 2286 Registered: 10-2003 Posted From: 71.58.71.157  Rating: N/A |
without it, the coach will accelerate a little harder with an increase in smoke. The amount will depend on injectors, turboed or not, and axle ratio. These were used in the cities to reduce the visible smoke mainly. Some can be adjusted. | ||
| Scott Crosby (Scott_crosby)
Registered Member Username: Scott_crosby Post Number: 133 Registered: 12-2011 Posted From: 99.100.88.196 Rating: N/A |
it does blow some black smoke at acceleration. Not a smoke screen but enough to notice. | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 2293 Registered: 10-2003 Posted From: 71.58.71.157 Rating: N/A |
we had to install one when we added turbo to our 4104 with high rear. Smoked black starting out till turbo spooled up. Throttle delay lowered smoke to an acceptable level. | ||
| Tom Christman (Tchristman)
Registered Member Username: Tchristman Post Number: 360 Registered: 1-2006 Posted From: 166.250.65.222 Rating: N/A |
There are two throttle delays that were used. One was the throttle delay as described-a small shock absorber built into the left head to slow the rack from opening-could be on any engine. Second was the fuel modulator-an air operated cylinder on the left head, but is controlled by turbo boost to prevent a cloud of black smoke on acceleration. As John said, it reduces the black smoke to an acceptable level. The fuel modulator was only used on turbocharged engines. Good Luck, TomC |