throttle throw length ?

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throttle throw length ?

Postby jethro » Sun Jul 26, 2015 11:31 pm

I am just about to plumb in my new throttle cable. I measured the linear displacement of the bell crank where it would hook up - I got close to 2 inches corresponding to idle to wot (wot being the maximum the whole linkage would move limited by the stop on the pump)
My job now is to rig the gas pedal so that I get that much travel.
My question is- is that 2 inches all real throttle travel- or is some of that on the upper end just dead zone- like do you get to max rpm at 1.5 inches ???????

I basically need to know this to know what the geometry of the pedal needs to be........
(using a spectre throttle cable kit)
Any experiences to share ?

Tim
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Re: throttle throw length ?

Postby fatty » Mon Jul 27, 2015 1:24 pm

There is a "dead space" in the throttle sweep. If you have it so it maxes out against the pump you might actually make less power. I posted a thread on it a while back and then ended up running that screw in to stop the throttle from swinging all the way back. It took some testing but I think I got it pretty close to max power. It would take some dyno time to get it exact.
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Re: throttle throw length ?

Postby oldestof11 » Mon Jul 27, 2015 3:18 pm

Fatty, which thread?
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Re: throttle throw length ?

Postby fatty » Mon Jul 27, 2015 5:35 pm

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Re: throttle throw length ?

Postby RCCUMMINS89 » Mon Jul 27, 2015 7:13 pm

That doesn't apply to a pump that is not maxed out though.
89 RC on shortened 92 diesel frame - NV4500 w/dual disc/4.10s on 37s. - Self built pump, "hot screw", lots of timing, True high volume low pressure lift pump, 62fmw/68/.7gated, 77lpm SAC Inj., Studs/O-rings,- 423/1220 Mustang - 11/16/2013 http://www.TheHungryDiesel.com full line dealer, if you don't see it please ask.
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Re: throttle throw length ?

Postby fatty » Mon Jul 27, 2015 10:11 pm

Yeah I suppose. He doesn't have anything in his sig so I just assumed he's going for max power.
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Re: throttle throw length ?

Postby jethro » Mon Jul 27, 2015 11:34 pm

Fatty and others----
I am in fact NOT going for max power. I wanted to have a chance for gas mileage. The folks who worked on my pump
(new O-rings) said they turned up the fuel about 20%. I have a stock powerstroke clutch plate so I don't want huge power.
If I am making 200HP that should be plenty. I am just wondering how far do you pull the rod attached to the pump until
you don't see any increase in rpm (or power) ? I just don't want to limit myself accidently by having my accelerator pedal
travel too short....... (got 3200 spring, +60 valve springs, Cro-mo pushrods, a1 head studs.... new head gasket, new oil seals,
KDP, new stock injector tips ,sort of a reliability package if you will... )

Perhaps this question depends on too many individual variable that I don't even know ????????
Would 2 inches (full travel of arm on pump) be too much or make pedal too sensitive ?
tim
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Re: throttle throw length ?

Postby CumminsPower59 » Tue Jul 28, 2015 8:31 am

Really doesn't matter how FAR (actual measurement) the throttle lever moves, as long as it gets full travel. Really can't go "too far" as the throttle lever assembly has the break over spring on it, or (I'm betting in your case) the full throttle stop is still in place. This is one of those things that is really variable between trucks, and the best thing is to get it mocked up close to your liking, and adjust from there. Put the go-pedal to the floor, and then look at how much the throttle lever has moved and go from there. Gonna have to just adjust and adjust again until it is in a good spot that everything gets it's full range of motion, full fuel and no binding anywhere.
Ike

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Re: throttle throw length ?

Postby fatty » Tue Jul 28, 2015 10:05 am

Yes it can go too far. Many people have noticed that max throttle is NOT the same as max power.
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Re: throttle throw length ?

Postby CumminsPower59 » Tue Jul 28, 2015 10:21 am

I stand corrected.
Ike

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Re: throttle throw length ?

Postby jethro » Tue Jul 28, 2015 6:17 pm

Looks like from what yall are saying- I should just take my best guess and pick a spot and see how it goes.
My engine does still have both stops both high and low.
On the positive side- the run from the pedal position on the firewall to the bell crank linkage is very close to straight- so the cable wont have any bends at all. No maybe low friction and long cable life (?)
I am going to try using the ford all electronic pedal- and add a steel arm above the pivot point- which will make it pull rearward
when the pedal is depressed. The throw length will determine ho long the extension will need to be from the pivot point.- and
the vertical position were I make the through-hole for the cable in the firewall.
Thanks for the input though ! I think I will try 2 inches and see what happens !
Tim
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Re: throttle throw length ?

Postby Tacoclaw » Wed Jul 29, 2015 5:44 pm

Everybody knows it's all about throttle throw girth. :grin:
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Re: throttle throw length ?

Postby jethro » Fri Aug 21, 2015 12:57 pm

Got the pedal extension done and in. It is about 6.6 inches from the pivot point.
That accidently gave me about 1/8 more pedal throw than the lever on the pump.
So basically I accidently got it perfect.
Had the throttle cable bent a little and it felt like a hack saw when I pressed the pedal.
I made an extended on the bracket to make the cable nearly straight- feels much smoother now !
No "sawing" also made sure that the ends of the cable housings were exactly in like with the cable core
to prevent fraying. (maybe)

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