Using a zener diode to defeat the 186 mph limit

I'm going to test what I've got, but I think a the 4.3v ZD is too low. 4.7 and 5.1 are on the way to test in my test kit.

Once I get that done, we can order 1000 of them for like $0.023 each.
 
(cougar694u @ Feb. 04 2007,20:23) I'm going to test what I've got, but I think a the 4.3v ZD is too low. 4.7 and 5.1 are on the way to test in my test kit.

Once I get that done, we can order 1000 of them for like $0.023 each.
Super.
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It's great to see someone working on a solution that
doesn't involve tearing the clutch apart! If I remember
you previous posts correctly, the GPS mod may not
deliver a speed de-restriction as expected.
 
(FAVahalik @ Feb. 06 2007,23:15) If I remember you previous posts correctly, the GPS mod may not deliver a speed de-restriction as expected.
I'm not sure, but the combined resistance if the two lands are connected is less than 5th gear, and actually directly between 4th and 5th gear. I'm not sure how the ECU interprets this, which is why I made the simulated MGPS circuit to test on the dyno.

4.7 & 5.1 ZD's should arrive today or tomorrow.
 
5.1v ZD & 1k Ohm resistor is really close, but not quite. Actually, with the 1k Ohm, Neutral appeared like 6th, 6th like 5th (almost exact), 5th was 4.25v, and the rest were pretty close.

I can try a 5.2 and a 5.6 (I hope fairchild doesn't start to question all the samples I've orderd
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) or we can roll with this.

Thoughts? Suggestions? Where can we buy the plugs?

**EDIT**
5.6v and 6v ZD's are on the way...
 
LOL! I ordered the other two ZD's last night at like 8pm and they showed up already today. Time to go home and nerd the fukc out.
 
Well, when I ordered the 5.6 & 6.0, I skipped the 5.2, which I think I should have gotten it.

I think I was wrong in my posting earlier. I tested it again right now and just the 5.1v ZD is pretty close: neutral is 4.44v, 6th is 4.34v, and 5th is 4.19v. With 330 Ohm resistor, neutral is 4.57v, 6th is 4.42, and 5th is 4.24v.

I think the 5.1v ZD may be perfect. The 5.6v did nothing because initial voltage is 5.14v (with that, I didn't bother with the 6.0). If I get a 5.2v ZD, it may or may not do anything. If I order it Sunday, it should be here Tuesday. I could also try a lower wattage ZD. The ones I got were 0.5 watt, but 0.35W is available. Maybe I could try a 0.35w 5.1v ZD and a 0.5w 5.2v ZD to see what the results are.

The difference, however, between 4.34 and 4.38 is less than 1%. I think I may just roll with that. All you'd have to do is tap into the red & black wire and attach the ZD in between them. All other gears worked perfectly and only 5th, 6th, and N are affected.

With only the 5.1v ZD:

1st through 4th were right on
5th = 4.53% less than stock measurement of 5th gear (4.19 vs 4.38)
6th = 0.92% less than 5th gear measurement (4.34 vs 4.38)
Neutral = 15.77% less than stock Neutral measurement (4.44 vs 5.14)

Now, since it's above 0.6v (per the FSM), it shouldn't throw a code. If the Neutral wire grounds, we should be okay. I need to find a micro/mini relay so I can open the ZD circuit when the blue wire is grounded to overcome this.

With the 5.1v ZD & 330 Ohm:

5th = 3.30% less than stock measured (4.24 v 4.38)
6th = 0.91% more than stock 5th gear (4.42 v 4.38)

It may be better to have it below because of any extra resistance that may occur.
 
Very interesting reading but now I have an excruciating headache........I certainly hope you guys post up a successful solution!  
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Well, I haven't had a chance really to mess with it, sorry. I was sent to Atlanta for the entire month of march, then two weeks after I got back, I broke my leg.

I ended up selling the busa and bought a 2005 gsxr1k. It just occurred to me that I can use it for testing since it has a gear readout on the dash.

I still have a busa GPS, so I can test the resistance values between my 1k and the busa to see if they're the same. If so, I can test with the resistor I mentioned earlier. I still have the circuits laying around, although I disassembled a few for parts I needed (MIL elims for the mustang).

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