Engine/Transmission (1994 - 1998) FUEL PLATE #ing system

[RKraiza]

Here's the queston; How does the fuel plate numbering system apply to how the plate performs? example a #0 compared to a #5 as compared to a #10 plate and so on. Does the lower # deliver more fuel quicker?

 

[wildmanben]

the lower the number gives you more fuel at WOT. do a search on plate profiles and you can see how the fuel rate comes at throttle increases.

 

[RKraiza]

thanks for the feedback. I have been doing many searches on the different plates. Still confused though. Full fuel at wot with a #5 vs. a #10 is still full fuel regaurdless of the plate size. Is it possably the timing of the fuel delivery: sooner verses later. If you no of any graph or reference chart that clearly shows the fuel plates, and there performance I would deffinatly like to be pointed in that direction. thanks again.

 

[Forrest Nearing]

full fuel is not full fuel... some plates will fuel more than others... just get a #0 plate and be done w/ it

 

[Mhannink]

full fuel is not full fuel... some plates will fuel more than others... just get a #0 plate and be done w/ it

i agree full fuel is not full fuel. it has to do w/ boost and throttle postion. take a ten for example, it has a half moon shape to it. when you depress the throttle fully you are demanding full fuel. what happens is the gov. arm rides the plate so when your rpms are low the gov arm is at the bottom of the plate. as boost builds up the arm rides up the plate, and in the case of the 10 it starts to fuel harder but only to a point after a time it will back out and start to defuel at the top end. this plate provides good power w/o a lot of smoke. a 0 plate has a flat profile basicaly it goes staight up. this is the ''full fuel'' plate basicaly it will fuel the same no matter what the boost is. the gov arm rides straight up as the rpms rise. boost plays the roll of when. when it goes to ''full fuel'' on top of your pump there is a housing called the afc housing. short for air fuel control. inside this housing is a diaphram that is connected to the intake system in some way shape or form(different for some models). what happens is a little bit of boost pressure bleeds off to this afc housing where it pushes on the diaphram. the dia. is connected to a small arm that sits next to the fuel plate. the profile on the arm is flat. it limits the amount of fuel by holding the gov arm back untill there is sufficent boost to push the arm past the plate where it will the ride the plate. this is how you control smoke levels w/ the higher hp more heavily fueled trucks. there is some smoke but if the afc spring(this fights the boost pressure on the dia. ) is tunned right it will not let the gov arm travel on the plate till there is enough boost and therefore air to burn all that fuel.



the reason why mr. nearing says to put a 0 plate in and be done w/ it is because its simple and builds lots of power. i also have a 0 plate in my truck and the afc spring is tight enough that i still get a good little cloud at low rpms but when i step on it, it clears up fast and runs clean but hard.



there are a few tricks you can do to the housing to get a little more out of it the first one and probably the easiest and cheapest is to take the fitting that connects the boost line to the housing and either drill it out or in my case i found one that was not metered in our shop that fit and put it in there. what this will do is allow more air in there so that it pressurizes faster moving that gov arm to the fuel plate sooner which equals more fuel sooner. another thing along w/ that and something a budy of mine did was to remove the above mentioned afc spring all together this makes for a very responsive throttle but also huge amounts of smoke which are hard to keep under control. also this makes the truck idle higher and impossible to bring down. what you can do though is order a lighter spring. this will allow you to keep ur idle down and your smoke under control at the same time as increasing your responiveness. the spring can be ordered from piers diesel for about 35 dollars.



really the best way to learn all this is just start playing w/ it pull your stock plate out and grind a profile in it see what its like. then regrind it and see again maybe its better maybe its worse. but play w/ it and also play w/ your afc spring. turn towards the engine= more smoke away= less. also might be a good idea to some how copy the plate profile onto a priece or paper so that if ya find one ya like you can get another plate and copy it. idk where to find stock plates but maybe someone else will chime in and know. there are a lot of little things that you can tinker w/ on these motors and really you have to play w/ it to find what you like best. dont be afraid to pull something apart its all really pretty simple stuff and unless your a complete dunce you should be able to put it back together. the first thing though if you havent already is get gauges. this will allow you to tune your motor better. those boost and egt gauges can tell you volumes about your motor. well i hope that helpsand if ya have any more ?s dont be afraid to ask.

 

[Joe G.]

The amount of fuel at WOT varies by RPM. The plate is really the full load throttle stop. What that means is that it is what limits the amount of fuel at WOT depending on RPM. The plate is not in play except at WOT. That is why increasing fuel with a plate does not affect MPG unless you stomp on it a lot.

 

[Cooker]

The plate is not in play except at WOT.

Joe,

I know you are a knowledgeable guy when it comes to these engines so I am not trying to discredit your knowledge, but are you certain this is accurate?

 

[Joe G.]

I think so. It is used to stop the governor follower from moving forward. That only happens at WOT. Since it is governor controlled a WOT condition may not require the pedal being flat to the floor. Once the governor follower hits the plate any more pedal movement will not result in more fueling. If I understand the way the pump works the rack position is controlled by the governor follower so when it is stopped from moving forward so is the rack. If I have this wrong, I hope some pump guru chimes in here.

 

[Turbo Thom]

Just stick in 4000 GSK and take the plate out.

 

[Mhannink]

I think so. It is used to stop the governor follower from moving forward. That only happens at WOT. Since it is governor controlled a WOT condition may not require the pedal being flat to the floor. Once the governor follower hits the plate any more pedal movement will not result in more fueling. If I understand the way the pump works the rack position is controlled by the governor follower so when it is stopped from moving forward so is the rack. If I have this wrong, I hope some pump guru chimes in here.

i think it would depend on the profile of the plate and the setting of the afc spring. if the plate had say a 10 profile then it would ride on the plate long before full fuel but it wouldnt fully ride the plate untill there was enough boost to move the afc arm out of the way. the afc spring also plays a roll because a lighter spring is gonna clear the plate sooner thena heavier one and so you would ride the plate sooner then too. so its not really a full load stop. i guess really its hard to describe what the plate really is cause it is affected by so many things. load, throttle postion, boost, rpms, and probably a few others. but i think we could all agree and say that the plate is really what controls the motor for the very reason that it controls the fuel, and w/ our motors fuel control is total control.

 

[pwerwagn]

a budy of mine did was to remove the above mentioned afc spring all together this makes for a very responsive throttle but also huge amounts of smoke which are hard to keep under control. also this makes the truck idle higher and impossible to bring down

The AFC has nothing to do with the idle. Mine is totally gutted at the moment, no difference in idle. I have a gutted AFC that I put on trucks with low power to rule out the AFC being bad. It doesnt change idle.

as boost builds up the arm rides up the plate

The gov lever rides up the plate based on RPM, not based on boost. The only thing boost referenced is the AFC housing itself.



Im not trying to "attack" your post, just clearing up some inaccuracies.



RKraiza,

The plate does more than just determine how much "full fuel" is. It also determines where full fueling occurs. The profile to when it occurs is as important as the amount of fuel in some cases. .

A #11 plate has much less low end fueling than a #10, with reduced fuel all around. A #100 plate for instance, has the low end profile of a 10, with the top end fueling of the #0. A #0 is just that, a flat plate that provides no control of fuel based on rpm. Its just as much fuel as your pump can deliver, based on the plate position as well as the AFC setting. basically, a #0 foward (not all the way. . ) with a gutted afc will provide the max amount of fuel your pump can deliver (aside from other mods, of course). Just remember, more fuel doesnt always equal more power. If it comes on to soon, It will "put out the fire". Thats the job of the AFC. I dont really see the point in a #100, cause if the AFC is functioning properly, the ramp at the bottom of the 100 isnt really needed...



--Jeff

 

[Joe G.]

Jeff,



From what you say I think I have it right. WOT is the governor follower contacting the plate. That can be more or less fuel depending on how for ahead the follower is allowed to go based on RPM and the plate shape. The AFC is in play until enough boost is there to move the AFC throttle stop out of the way. At that point the plate takes over the job of limiting fuel at WOT.



My direct experience with Bosch pumps is with surplus marine Buda engines from WWII. The rack and plungers appear to be the same. The governor on a P7100 is quite a bit different than the one on the Buda. It maintained constant RPM regardless of load. Or tried to anyway. The engines were 40 HP.

 

[Mhannink]

The AFC has nothing to do with the idle. Mine is totally gutted at the moment, no difference in idle. I have a gutted AFC that I put on trucks with low power to rule out the AFC being bad. It doesnt change idle.





The gov lever rides up the plate based on RPM, not based on boost. The only thing boost referenced is the AFC housing itself.



Im not trying to "attack" your post, just clearing up some inaccuracies.



RKraiza,

The plate does more than just determine how much "full fuel" is. It also determines where full fueling occurs. The profile to when it occurs is as important as the amount of fuel in some cases. .

A #11 plate has much less low end fueling than a #10, with reduced fuel all around. A #100 plate for instance, has the low end profile of a 10, with the top end fueling of the #0. A #0 is just that, a flat plate that provides no control of fuel based on rpm. Its just as much fuel as your pump can deliver, based on the plate position as well as the AFC setting. basically, a #0 foward (not all the way. . ) with a gutted afc will provide the max amount of fuel your pump can deliver (aside from other mods, of course). Just remember, more fuel doesnt always equal more power. If it comes on to soon, It will "put out the fire". Thats the job of the AFC. I dont really see the point in a #100, cause if the AFC is functioning properly, the ramp at the bottom of the 100 isnt really needed...



--Jeff

on the afc changing idle. it was the only mod we did at that time and thats when the idle changed so i dont know whats up w/ that. as for the rest thanks for clearing it up. i was thinking what you said i just didnt put it in the right words.

 

[pwerwagn]

At that point the plate takes over the job of limiting fuel at WOT.

Yeah, I think the concept is right. I have one thouhgt though: The plate also changes what WOT is. to exaggerate the situation, imagine a #0 plate full foward, and then a stock plate full backward.

At half throttle with the #0 plate full foward, the gov lever is definitley not gonna contact the plate.

Yet at half throttle with the stock plate full rearward, I think it might?

(maybe not half throttle, but just to get the point... ).



So while I totally agree with the plate only changing fuel at WOT, I also think to some extent there may be a slight change in when actual WOT occurs. And in some cases WOT might be the same as half throttle, in which case fuel mileage could change if you use the same throttle position as before. Yet, If you are just accelerating at the same pace as before, you will not need the extra power.



I think the safer statement is the plate only affect mileage if you use the "power", not only if you use WOT.

Does that sound Tangible???? heck, I dunno!



-Jeff

 

[pwerwagn]

on the afc changing idle. it was the only mod we did at that time and thats when the idle changed so i dont know whats up w/ that

I dont know either. Musta been a fluke. Coincidence. Otherwise everytime someone slid their AFC housing foward, the idle would change.



The idle control has no relation to the AFC.

 

[HoleshotHolset]

In my humble opinion, the "#0" plate needs to be renamed to "#1".

I'm running the REAL #0 plate in my '94. :-laf



Matt

 

[Joe G.]

Yeah, I think the concept is right. I have one thouhgt though: The plate also changes what WOT is. to exaggerate the situation, imagine a #0 plate full foward, and then a stock plate full backward.

At half throttle with the #0 plate full foward, the gov lever is definitley not gonna contact the plate.

Yet at half throttle with the stock plate full rearward, I think it might?

(maybe not half throttle, but just to get the point... ).



So while I totally agree with the plate only changing fuel at WOT, I also think to some extent there may be a slight change in when actual WOT occurs. And in some cases WOT might be the same as half throttle, in which case fuel mileage could change if you use the same throttle position as before. Yet, If you are just accelerating at the same pace as before, you will not need the extra power.



I think the safer statement is the plate only affect mileage if you use the "power", not only if you use WOT.

Does that sound Tangible???? heck, I dunno!



-Jeff

Exactly. In effect, practical WOT is set by the plate. When the governor follower hits the plate that's all the fuel you get regardless of how much pedal it takes to do that.

 

[pwerwagn]

Exactly. In effect, practical WOT is set by the plate. When the governor follower hits the plate that's all the fuel you get regardless of how much pedal it takes to do that.

Joe,



Thats the way I see it!!



Jeff

 

[Ridesamule]

let me ask one more question to go with this thread. Now that I have updated my transmission I am thinking of going to a 100 plate.



If I am pulling a load at say 50 and hit a sudden steep hill. Will the governor automaticaly move the foot forward in an attempt to continue it's current momentum. Ppossibly contacting the plate at just 1/4 throttle?

 

[Joe G.]

I don't think so. Wrong kind of governor. That's how tractors and marine diesels work.