High-Gain Busa
Registered
After looking at the Zener diode mod which I never got a chance to get to I pondered what the voltage threshold was for the different gear indications. The 5th and 6th gear voltage difference is quite large, 4.39v to 4.72v. The resistance to achieve that is even larger, 6,800 ohms for 5th and 15,000 for 6th. Changing the equivalent resistance is very easy and affects a higher resistance much more than a lower resistance.
So I said to myself, SELF... let's leave everything as it is and just create a lower resistance for 6th that won't affect 1st through fifth. This is what my calculator came up with that is also easily accessible at any Rat Shack store.
22,000 ohms in parallel with the existing circuit will drop the 6th gear resistance from 15,000 ohms to a very acceptable 8,918 ohms. Much too low for the ECM to realize it's in 6th. The kicker is using that high of resistance, it doesn't affect the lower resistance values enough to alter what the ECM thinks is 1st through fifth so you get 1N23455 and no RPM limiter.
In my testing, I once in a while even got a momentary 6th gear indication and it quickly goes back to 5th which I thought was kind of cool letting me know I did hit 6th.
THIS IS NOT A TRE MOD! although they are just as easy to do but will always indicate 5th. I have my opinion about TRE's and don't see the need for extra timing below 4000 RPM. On a hot day where the air is thinner (always a little thinner here in Denver) you don't want a crap load of timing at low RPM's under heavy load unless you want to create ventilation holes in the tops of your pistons.
Once I crack the throttle, the rest of the gears never see anything below 4000 RPM anyway
This mod can be made as pretty as you want... you can even install a switch if you want to turn it on and off. This is a no frills 20 cent mod that achieves the same thing as units that are wrapped in PVC, drowned in epoxy (so you can't see the goodies inside) and plug in using the OEM connectors.
DISCLAIMER:
Although this mod works on my 2008 Busa in eliminating the rev limiter, I am not responsible if it gives your Busa more speed, makes it spit fire and burns ZX14's behind it to the ground.
So I said to myself, SELF... let's leave everything as it is and just create a lower resistance for 6th that won't affect 1st through fifth. This is what my calculator came up with that is also easily accessible at any Rat Shack store.
22,000 ohms in parallel with the existing circuit will drop the 6th gear resistance from 15,000 ohms to a very acceptable 8,918 ohms. Much too low for the ECM to realize it's in 6th. The kicker is using that high of resistance, it doesn't affect the lower resistance values enough to alter what the ECM thinks is 1st through fifth so you get 1N23455 and no RPM limiter.
In my testing, I once in a while even got a momentary 6th gear indication and it quickly goes back to 5th which I thought was kind of cool letting me know I did hit 6th.
THIS IS NOT A TRE MOD! although they are just as easy to do but will always indicate 5th. I have my opinion about TRE's and don't see the need for extra timing below 4000 RPM. On a hot day where the air is thinner (always a little thinner here in Denver) you don't want a crap load of timing at low RPM's under heavy load unless you want to create ventilation holes in the tops of your pistons.
Once I crack the throttle, the rest of the gears never see anything below 4000 RPM anyway
This mod can be made as pretty as you want... you can even install a switch if you want to turn it on and off. This is a no frills 20 cent mod that achieves the same thing as units that are wrapped in PVC, drowned in epoxy (so you can't see the goodies inside) and plug in using the OEM connectors.
DISCLAIMER:
Although this mod works on my 2008 Busa in eliminating the rev limiter, I am not responsible if it gives your Busa more speed, makes it spit fire and burns ZX14's behind it to the ground.
