Is a tune absolutely necessary for this?...

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Sep 27, 2006 | 04:01 PM

Stroker2112

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From: Nebraska

Is a tune absolutely necessary for this?...

Guys,

I just replaced a 323ci (5.3L) with a 408ci(6.7L)....the intake/TB,MAF, and everything else (fuel pump, electrical harness, all accessories) are the same.

What's new are the LT headers, 44lb injectors, bigger cam and CNC'c 243 heads. The 408 fired right up, sounds great and idles perfect.

So my appointment with the dyno-shop isn't for another 2 1/2 weeks....so you know what I'm thinking here....

What could I potentially screw up by taking it for a spin to break in the ring seals?...

Stroker2112

Sep 27, 2006 | 04:28 PM

doobieboy

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maybe. That tune isnt setup for those injectors lol I suggest you bite the bullet and wait for the shop to tune that bitch

Sep 27, 2006 | 04:34 PM

98 Raptor TA

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From: Charleston, SC

Get it tuned. Of course it may not be "absolutely necessary" cause it may run without a tune, but it wont run PROPERLY. Your a/f will most likely be really off.

Sep 27, 2006 | 04:38 PM

Stroker2112

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Joined: May 2006

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From: Nebraska

OK, so would the larger injectors spray more than the old ones even if the fuel delivery setting is fixed in the PCM?...if so then I understand the a/f will be too rich (but how much richer?...what would happen if someone ran too rich for say....10-20 miles?) I haven't upgraded the fuel pump yet either...