OK, for those of you who don't own a heavily-modded 91-94 240sx, and you still have stock ECU, ignition, manual transmission, etc., look here.
First off, I can't be held responsible for anything that may happen to your car in the process of doing any of these low-buck mods. Please refrain from attempting any of these mods on your car unless you are at least compenent enough to do the job right, and be able to return the mod to its former un-modded state if the mod does not work correctly or as expected.
These are low-buck or no-buck mods as a primer for those of you who are just learning about your 240sx, and need to experience a little cause and effect. Some of these mods require some knowledge of mechanics, electrical, and some math to accomplish what is being instructed.
Ignition timing and spark:
Ignition timing is a very touchy issue to attack first, since it can be detrimental to what you might want to achieve. In most cases though, ignition timing can be altered to allow for more off-the-line speed.
Personally, i run mine at 23º BTDC (Before Top Dead Center), and allow the ECU to adjust timing as needed. It does this through the knock sensor located between the intake runners #2+3 on the cylinder head. The knock sensor is a peizo-electric device, kind of like a microphone, that detects knock and ping and sends this information back to the ECU to retard timing until no knock is "heard".
So far, after many trial runs and many adjustments, I settled on 23º BTDC because I get no knock sensor activity to the ecu, and gain the extra speed and fuel mileage without sacrificing top end performance.
The ignition coil is another matter, which requires some electrical knowledge, (how to cut/crimp wires/butt connectors/spade lugs, use of a multimeter).
An upgraded ignition system could yield surprising results if done properly, or could prove to be a headache if not thought out and planned first.
I personally use a MSD blaster 2 coil with the factory wiring intact (use the ECU signal and power diode originally installed). The power factor goes up, but so does the amount of spark to the plug, allowing for a longer spark gap on the plug. OHMs are lower on the replacement coil, so heat sinking the power module is a good idea. After this is done, you should be able to trim at least .5 second off your 0-60 time.
But, if you're like me, and you find that you hit the speed limiter in a run on the track,(you are running those speeds on the track and not the street, right?) there is an easy fix that almost everyone else has done, im sure.
The speed displayed comes from the speed sensor on the tail end of the transmission, but it goes to the ECU first to limit speed to between 110-115MPH. This wire is green with a yellow trace, located on the ECU. It is located on the 8th pin along the top of the wire plug to the ECU (if looking from the top). Snip this wire and tape it off. If done correctly, you should only be limited to the rev limiter, which is around 127-130MPH, or 6600RPM in fourth/5000RPM in 5th.
For the sake of safety, and to keep honest people honest, i will not get into disconnecting the rev limiter. Doing so could put you in a very hazardous position if you go more than double the speed limit on the road. Furthermore, who needs to do more than 130MPH anyway? If your car is not set up to handle those speeds, you shouldn't try it.
Remember to always be safe and follow all road rules when driving, and save the racing for the track.
First off, I can't be held responsible for anything that may happen to your car in the process of doing any of these low-buck mods. Please refrain from attempting any of these mods on your car unless you are at least compenent enough to do the job right, and be able to return the mod to its former un-modded state if the mod does not work correctly or as expected.
These are low-buck or no-buck mods as a primer for those of you who are just learning about your 240sx, and need to experience a little cause and effect. Some of these mods require some knowledge of mechanics, electrical, and some math to accomplish what is being instructed.
Ignition timing and spark:
Ignition timing is a very touchy issue to attack first, since it can be detrimental to what you might want to achieve. In most cases though, ignition timing can be altered to allow for more off-the-line speed.
Personally, i run mine at 23º BTDC (Before Top Dead Center), and allow the ECU to adjust timing as needed. It does this through the knock sensor located between the intake runners #2+3 on the cylinder head. The knock sensor is a peizo-electric device, kind of like a microphone, that detects knock and ping and sends this information back to the ECU to retard timing until no knock is "heard".
So far, after many trial runs and many adjustments, I settled on 23º BTDC because I get no knock sensor activity to the ecu, and gain the extra speed and fuel mileage without sacrificing top end performance.
The ignition coil is another matter, which requires some electrical knowledge, (how to cut/crimp wires/butt connectors/spade lugs, use of a multimeter).
An upgraded ignition system could yield surprising results if done properly, or could prove to be a headache if not thought out and planned first.
I personally use a MSD blaster 2 coil with the factory wiring intact (use the ECU signal and power diode originally installed). The power factor goes up, but so does the amount of spark to the plug, allowing for a longer spark gap on the plug. OHMs are lower on the replacement coil, so heat sinking the power module is a good idea. After this is done, you should be able to trim at least .5 second off your 0-60 time.
But, if you're like me, and you find that you hit the speed limiter in a run on the track,(you are running those speeds on the track and not the street, right?) there is an easy fix that almost everyone else has done, im sure.
The speed displayed comes from the speed sensor on the tail end of the transmission, but it goes to the ECU first to limit speed to between 110-115MPH. This wire is green with a yellow trace, located on the ECU. It is located on the 8th pin along the top of the wire plug to the ECU (if looking from the top). Snip this wire and tape it off. If done correctly, you should only be limited to the rev limiter, which is around 127-130MPH, or 6600RPM in fourth/5000RPM in 5th.
For the sake of safety, and to keep honest people honest, i will not get into disconnecting the rev limiter. Doing so could put you in a very hazardous position if you go more than double the speed limit on the road. Furthermore, who needs to do more than 130MPH anyway? If your car is not set up to handle those speeds, you shouldn't try it.
Remember to always be safe and follow all road rules when driving, and save the racing for the track.
. ill post some pics of me going over 115mph and ill have proof that it works.:happyfing
