 
     |
| Need some help with a tune on an F-150 (Page 1/1) |
|
RayOtton
|
NOV 03, 02:24 PM
|
|
I've been restoring this over the past three years. It is a 1998 NASCAR edition F-150. I owned it, sold it and bought it back in rough condition with 200 K on the odometer. There were only 3000 made for the 50th anniversary of NASCAR.
It's got a new 4.6L engine and automatic.
I installed a 3" exhaust, CAI and a 75mm Throttle body.
I've added a 93 Octane performance tune using my SCT X3 unit. On top of the canned tune the unit allows for some engine / transmission adjustments. I increased the line pressure to the tranny and I increased the WOT timing by 2 degrees without any pinging. These made a marked improvement in performance.
Another of the engine adjustments allows for up to 15% increase in WOT air/fuel.
So here's the question.
The stock throttle body was 68MM, the new one is 75MM. That's pretty close to a 10% increase. Would that equate to a 10% increase in the WOT air/fuel or are there other factors I'm not aware of?[This message has been edited by RayOtton (edited 11-03-2016).]
|
|
|
|
phonedawgz
|
NOV 04, 06:33 PM
|
|
|
If it has a divorced MAF then it shouldn't need an adjustment. The MAF will read higher air flow.
|
|
|
|
RayOtton
|
NOV 05, 05:37 AM
|
|
Thanks for the response.
Not sure what "divorced" means.
I do understand how the MAF works so I guess I'm wondering why the tuner allows the user to change the WOT air/fuel ratio.
|
|
|
|
E.Furgal
|
NOV 05, 06:46 AM
|
|
|
limited number collector, and you replace the 4.6 instead of rebuilding the # matching parts.
|
|
|
|
RayOtton
|
NOV 05, 07:54 AM
|
|
Would have done it if possible but the block was unsalvageable.
|
|
|
|
edfiero
|
NOV 06, 09:36 AM
|
|
|
It's an increase in air only if the engine needs it / can use it.
|
|
|
|
pokeyfiero
|
NOV 07, 10:23 PM
|
|
|
Have same engine, same throtle body. Computer handles it fine.
|
|
|
|
RayOtton
|
NOV 08, 06:50 AM
|
|
Ok, thanks.
Really makes me wonder why they would even bother having the option of adjusting the WOT settings.
|
|
|
|
SR-71
|
NOV 10, 11:49 AM
|
|
Mass air flow will not change with the size of the throttle body (unless it's already or will become a major restriction). This is not a big change, Therefore the lambda should not change.
With your bigger throttle body, the air flow velocity will decrease. This will shift your torque curve a little higher in the RPM range. It may or may not be noticeable via a calibrated butt.
|
|
|
