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Notice on LTI & SOHC Mustangs?


Dave Schotz

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Hey guys... looks like according to the rules that the only cars with actual adjustable distributors being 3rd gen F-Body's and 5.0 Mustangs.. would be able to advance their timing legally... is this correct?

 

All LT-1 Cars... and SOHC Mustangs... have to run factory starting point for timing... and not allowed to tune the timing curve at all?

 

Thanks for the info!

 

Dave

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Dave, I'm not sure how the Mustangs work, but regarding LT1s (and LS1s), you're correct.

 

To alter the timing curve (advance) on an LT1 you either need to mess with the computer, or get an MSD adjustable opti. Both are no-nos in the rules.

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The Ford SOHC and DOHC motors require a sensor wheel bolted to the front of the balancer and the stock crank sensor is moved out to line up with it and it can be adjusted usually around 20 deg total (-+10 deg).

I believe stock timing is 10 deg base, the rest is all computer controlled.

 

Or a chip/programmer.

 

The rules don't allow either so I'll agree that timing adj on a 4.6L is not legal.

 

Timing wheel/sprocket looks simular to this:

http://www.steeda.com/products/_enlarged/4.6L_timing_adjuster.php

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Though 3rd. gens are adjustable, they have dynamic timing.

Computer listens via knock sensor in the water jacket and adjusts accordingly.

Base timing is at distributor.

 

jb

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Thanks Guys... I'm learning all this stuff... and appreciate the clarification.

 

The Knock sensor comment for Third gen's Jeff is interesting... technically... does that knock sensor need to connected?

 

Thanks!

 

Dave

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.. technically... does that knock sensor need to connected?

 

Thanks!

 

Dave

Well, I can only speak for the 7730 ecm (91-92 tpi), which would not be happy. Never tried it but sure it would puke codes till it turned off dynamic timing. Ecm must remain stock. Memcal must be stock.

 

jb

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Can be connected to the harness, but mounted off engine...

 

So how would the ecm test it?

I understand it dails timing looking for the knock sensor.

If it doesn't report, you get a code.

 

jb

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Jeff, it's still connected to the harness, so the ECU is happy. But if you were hypothetically to then mount it in a padded case underhood, it would never shake, which would make the ECU think the motor is NOT knocking, which would result in the ECU never pulling timing.

 

This is also part of the reason people go to the LT4 KS. That car had a hotter cam in it, which made it run a little "rougher". If the normal KS was in place, the rough shake of the motor made the KS think the motor was actually knocking, and would pull timing. The LT4 KS has a higher level of tolerance to shake before it sends a signal to pull timing to the ECU.

 

Not that I'm advocating moving the KS off motor, that removes the ability of the ECU to sense knock and pull timing before engine meltdown. However, if one were so inclined, not having that insurance is worth the "extra" HP.

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Hmm, I thought the 305s HAD a KS. Just connect to a KS that won't ever see knock (ie not on the motor).

 

Of course the LT4 KS "mod" only applies to the LT1 - I thought that's what this topic was about.

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