High idle function/effects

How to make it go fast

Moderators: Greenleaf, KTA, BC847, Richie O

High idle function/effects

Postby spencerdiesel » Tue Feb 06, 2018 7:48 pm

I thought this would be a super common topic (well it has been, but I haven't seen definitive text to answer my mental questions yet), but I didn't find as many threads as I thought I would.

What does the actual position of the throttle shaft (when it is allowed to travel past stock position) affect other than allowing higher no load speed?

Is there any potential increase of fueling allowed BELOW defuel speed by allowing further travel of the throttle shaft?

Because most of us have the high idle backed out beyond stock, has anyone done a back to back dyno or track run with the high idle at stock (assuming a 3200 spring or stiffer is in place) vs backed out?

Internally, what happens to fueling capabilities with a "maxed" (loaded term) IP as a result of stock vs "farther than stock" throttle shaft position?

Thanks yall
1992 W250, 5 speed, 4.10, Ext. cab Ext. bed, 12.5k winch, 75 gal. fuel tank

Fuel: THD 12 psi piston pump, THD fuel pin, 366 spring, fuel screw bottomed @ 3 turns, timing bumped 3/16"
Muffler delete
spencerdiesel
14mm rotor
 
Posts: 1022
Joined: Tue Oct 27, 2015 4:02 pm
Location: Brevard, NC

Re: High idle function/effects

Postby spencerdiesel » Thu Feb 08, 2018 7:51 pm

Ello?
1992 W250, 5 speed, 4.10, Ext. cab Ext. bed, 12.5k winch, 75 gal. fuel tank

Fuel: THD 12 psi piston pump, THD fuel pin, 366 spring, fuel screw bottomed @ 3 turns, timing bumped 3/16"
Muffler delete
spencerdiesel
14mm rotor
 
Posts: 1022
Joined: Tue Oct 27, 2015 4:02 pm
Location: Brevard, NC

Re: High idle function/effects

Postby Remps » Fri Feb 09, 2018 8:08 am

To me, my sotp experience with a flush high idle screw (and beyond) is that it adds power/fuel above a certain rpm/load. Trying to utilize it too early results in a bit of power loss. I'm a fan of chopping the high idle stop off the throttle linkage. :grin:
'90 D250 R/C,727,IC,6x.009's,1/8" bump,fuel psi,straight pipe w/5" stack.
'90 W250 R/C,47rh,K@N,HX35,1/8" bump,2nd gen IC,boost,egt,trans temp.3.07's.
'96 2500 S/C L/B,2wd,NV5600,3.54 L/S,cai,egt,pacbrake,mbrp exhaust,10 plate.
Bring back the Bank of Canada, PRE- 1974.
User avatar
Remps
14mm rotor
 
Posts: 1094
Joined: Sun May 03, 2009 12:57 am
Location: Saskatchewan
Top

Re: High idle function/effects

Postby spencerdiesel » Fri Feb 09, 2018 7:16 pm

Thanks Remps. If there is no gain with my limited fueling, I may set it back to stock so that:

Instead of relying on my human self to slowly let off the throttle when approaching 3300 rpm WOT, I can hold it on the floor and let it defuel on its lonesome. So when attempting to leave the odessy beside me, I don't have to worry about meticulous backing off throttle between shifts to preserve the FSS.
1992 W250, 5 speed, 4.10, Ext. cab Ext. bed, 12.5k winch, 75 gal. fuel tank

Fuel: THD 12 psi piston pump, THD fuel pin, 366 spring, fuel screw bottomed @ 3 turns, timing bumped 3/16"
Muffler delete
spencerdiesel
14mm rotor
 
Posts: 1022
Joined: Tue Oct 27, 2015 4:02 pm
Location: Brevard, NC
Top


Return to The good stuff

Who is online

Users browsing this forum: No registered users and 1 guest