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Need some help with a tune on an F-150 by RayOtton
Started on: 11-03-2016 02:24 PM
Replies: 8 (174 views)
Last post by: SR-71 on 11-10-2016 11:49 AM
RayOtton
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Report this Post11-03-2016 02:24 PM Click Here to See the Profile for RayOttonSend a Private Message to RayOttonEdit/Delete MessageReply w/QuoteDirect Link to This Post
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).]

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phonedawgz
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Report this Post11-04-2016 06:33 PM Click Here to See the Profile for phonedawgzClick Here to visit phonedawgz's HomePageSend a Private Message to phonedawgzEdit/Delete MessageReply w/QuoteDirect Link to This Post
If it has a divorced MAF then it shouldn't need an adjustment. The MAF will read higher air flow.
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RayOtton
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Report this Post11-05-2016 05:37 AM Click Here to See the Profile for RayOttonSend a Private Message to RayOttonEdit/Delete MessageReply w/QuoteDirect Link to This Post
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.
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E.Furgal
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Report this Post11-05-2016 06:46 AM Click Here to See the Profile for E.FurgalSend a Private Message to E.FurgalEdit/Delete MessageReply w/QuoteDirect Link to This Post
limited number collector, and you replace the 4.6 instead of rebuilding the # matching parts.
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RayOtton
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Report this Post11-05-2016 07:54 AM Click Here to See the Profile for RayOttonSend a Private Message to RayOttonEdit/Delete MessageReply w/QuoteDirect Link to This Post
Would have done it if possible but the block was unsalvageable.

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edfiero
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Report this Post11-06-2016 09:36 AM Click Here to See the Profile for edfieroSend a Private Message to edfieroEdit/Delete MessageReply w/QuoteDirect Link to This Post
It's an increase in air only if the engine needs it / can use it.
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pokeyfiero
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Report this Post11-07-2016 10:23 PM Click Here to See the Profile for pokeyfieroClick Here to visit pokeyfiero's HomePageSend a Private Message to pokeyfieroEdit/Delete MessageReply w/QuoteDirect Link to This Post
Have same engine, same throtle body. Computer handles it fine.
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RayOtton
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Report this Post11-08-2016 06:50 AM Click Here to See the Profile for RayOttonSend a Private Message to RayOttonEdit/Delete MessageReply w/QuoteDirect Link to This Post
Ok, thanks.

Really makes me wonder why they would even bother having the option of adjusting the WOT settings.
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SR-71
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Report this Post11-10-2016 11:49 AM Click Here to See the Profile for SR-71Send a Private Message to SR-71Edit/Delete MessageReply w/QuoteDirect Link to This Post
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.
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