What does fuel screw control?

[Jgolden]

When the fuel screw is turned in, does that provide more fuel flow at all points of the throttle or only at WOT?

Can the screw setting be a problem if turned in too far? Can throttle position be used to avoid problems?

Why didn't I do this in warmer weather?



I was planning to back out the screw a little, since I have more fuel than I can use without high egt's, but this couch is warm and my repair bay has the sky as a roof. In my setup the pump is not easy to reach. (I ,hope to take off in the direction of the equator soon, and this was on my "ought to" do list)

The max point on my pedal can be adjusted, no problem, or I just won't push down so far.

Thanks any info.

 

[cerberusiam]

Fuel is upped across the range of operation. Is why idle adjsutemnts normally have to be done when fuel screw is tweaked. To increase fuel and rpm to match a curve the governor and delivery assembly needs to be setup differently internally.



Depending on the pump, fuel, governor, etc, screw in too far can mean a runaway. Every setting needs to be checked that it will return to idle promptly after blipping the throttle. If it doesn't return or returns slowly you are on the edge.



I am thinking, very diligently at this point, that about 100 miles north of Matagorda Island would be far enough south to start with?

 

[Greenleaf]

Why didn't I do this in warmer weather?

Cuz you had to replace the starter motor



Don't press down so far. Seriously. That is what I do. Sometimes it scares the dickens outta me when I do, not to mention the extream EGT #'s and the cost of a speeding violation. My exhaust temps will rocket to 1,500° in zero time even with the air flow mods, so I just don't push down on the shinny peddle very often.



You carry like 140 gallons of tap water, right? SNOW Perf. will hook you right up.

 

[Jgolden]

I get the heat without the speed, for sure. If I ever get a speeding ticket, then the traffic code is fully enforced, and the laws of physics have been repealed.

The water injection is on the list, and I do usually have lots of water with me.

Interesting to learn that fuel is stepped up throughout the cycle.



Greenleaf: good memory on the starter. My wife remembers me saying," Don't worry I'll replace it when we get back. " When I told her I could have called you and got advice, instead of touring the Ashland/Mansfield truck parts world, she made me print out the "travel companion" list.



Thanks for the info folks.

 

[Jgolden]

I am thinking, very diligently at this point, that about 100 miles north of Matagorda Island would be far enough south to start with?

Or even farther. I knew Global warming would let me down. Thanks

 

[PToombs]

Joe, start said unit of motion. Turn heat knob to far right. Go have cup of coffee. Return to said unit, remove doghouse. Adjust screw required amount. Replace doghouse. Turn off unit. Go in house. Thaw out Gonads. Go towards Equator at proper time. Make sure you have Travel Companion. ( To keep spousal unit docile. ) Enjoy warmer climes. Drink copious amounts of liquid refreshment. Don't forget us poor schmucks in snowbelt. Have a safe trip.

 

[Jgolden]

Good advice, Pete. Just do it I think is the clue.

Hope you have a warm weather "meet and greet", or do you guys from western NY pay no attention to temps?

Do they have SOP every year? Same month?

Stay warm.

 

[PToombs]

Good luck, It better be warm,Yes, Yes, and You betcha!

I'll send you a PM to keep you in the loop about the Spring Thing.

 

[cerberusiam]

Or even farther. I knew Global warming would let me down. Thanks

Any farther and gonna have a language problem. One step at a time... ... :-laf :-laf

 

[JLEONARD]

 my repair bay has the sky as a roof

I hear you... I have a local guy comming over this am . . I'm going to do some tweakin' on his 89 stocker for him. Temps are supposed to "warm up" to about mid tenns here. That will be good... the furnace needs a break!

 

[1stgen4evr]

"and my repair bay has the sky as a roof. "





I have one of those zero overhead shops myself. Not too nice even in Georgia weather. In the summer, dark colors warm to untouchable temperatures.



James

 

[pepecat]

What setup are you guys using to get egt problems? With my stock non i/c injectors I can't get it over 1050 or so on a LONG WOT run up a grade accelerating past 100 mph in 5th. on the flat ground , forget it. It's at 650 egt cruising @ 85 mph. But the needle climbs so slow now. I have the fuel turned up enough to get 34 psi at high rpm <2600 with a 16cm/54 h1c turbo. It is approacing runaway the fuel is turned up so high, and timing is bumped. A black cloud emits whenever it is floored. Anyway point being, get a BHAF, full manderal 4" exhaust with 3" DP... This rig will spin the tires on starting roll in 2nd gear when the turbo lights. I would make these upgraded before snowmeth or whatever chemical coolers you guys are talking about, and needless to say, an air to air intercooler isn't even necessary to control egts with this level of fueling.

At this level of fueling before with stock intake and 3" exhaust, egt's would shoot up to +1200 so fast.

 

[Jgolden]

I've got a BHAF with a HTT stage II and air supply upgrades. As my sig shows it is a Motorhome that comes in at about 12,000 to 14,000 lbs. My heat will max out climbing a long grade or if I try to accelerate too fast, on the level.

Mostly I think it is the natural limits on how quickly I can convert fuel into forward motion with out excess heat. Generally the fuel pedal is the answer to the egt's. This rig has come a long way since I started to increase the power.

With a 4spd Allison auto,up a steep grade, if I shift to third RPM's stay up egt's drop. I can climb all day.

My original question was to help me understand the fuel cycle, and how it would effect my top end demand.

With an unloaded Dodge the fuel is converted to speed, before it gets too hot. More choice of gears also helps the trucks even when towing.

I think a water injection set up would help in summer and going up grades.

Thanks

 

[pepecat]

Yes indeed, that is a lot more weight to lug around... egt's will be an issue. Some sort of intercooler, chemical or air to air will help a lot, for sure.