taking off top speed limit

[cloudpicker]

i did research about taking off speed limit,and i found out 3 method
i have a 91' 240sx se hatchback 5 speed.

1)install an auto ecu
2)install an apexi rev speed meter
3)cutting some wires

may i know does all these method works??and if yes which method is the most reliable one??pls help

[ch1873857]

man go with number 3. i used to top out 111-113, cut the wire and i hit 130 no problems, free and reliable. but... i think its illegal in cali

[Blues13]

Yea, I cut the wire as well.. works great. I have the SR, so not sure if its the same on the KA.. but does 135+ after.

[cloudpicker]

thanks guys can you tell me more which wire is it easy to find??coz' in the search it's kinda complicated..

[Steeles]

Originally posted by cloudpicker
thanks guys can you tell me more which wire is it easy to find??coz' in the search it's kinda complicated..

yellow wire with a green strip going into the ECU. I would recommend wirinng in a switch when you do it. (on = speed limiter off = no limit) especially if you still have cruise control that you wanna keep. plus it keeps you from having loose wires floating around.

[ch1873857]

woah!! so if you cut the wire your cruise control doesnt work???? because mine is dead and i was wondering why. i guess i should wire up a switch

[Steeles]

Originally posted by ch1873857
woah!! so if you cut the wire your cruise control doesnt work???? because mine is dead and i was wondering why. i guess i should wire up a switch

yes without that wire the ecu dosent get a speed signal... since the ecu maintains your speed when you engage cruise control it cant do so if it dosent know how fast your going....

[VersionS13]

If you don't run a switch, will a CEL come on?

[hurleyboi514]

is that true about you being able to use an auto ecu? b/c ive got one at my house, its just sitting there... '92 auto ka24de ecu, the car is a '91 ka24de manual.

[memphiss13]

anybody know what color wire to cut on an SR? 115 is too slow.

[Steeles]

Originally posted by rookie2nr
anybody know what color wire to cut on an SR? 115 is too slow.

same wire I said before. like I said I just did it the other week.

HURLEYBOI - dunno about the auto ecu. try it and see :) let us know.

version - I dont think so... but i dunno for sure...

[HKrpS13]

Originally posted by Steeles
I would recommend wirinng in a switch when you do it. (on = speed limiter off = no limit) especially if you still have cruise control that you wanna keep. plus it keeps you from having loose wires floating around. [/B]
Is it safe to turn the switch on and off while you're driving?

[Bill Roberts]

Yellow wire.


You really don't want to do 145 in a 240SX without :

1. Serious brake upgrade
2. Being on a racetrack.
You do if you are:

1. Seeking a death wish.
2. Want to go beyond the intended capabilities of rims, tires and suspentions and aerodynamic stability.


Our cars wallow like a garbage scowl at 150MPH.

240SX's should NEVER be driven above 135MPH. too much in your hands, too quick, too much to lose.


Suspention and tires are #2, brakes #1.

Get a corvette if you want to do 160 or so.

[RedlineRacer]

I was about to ask that question, cause I have my speed limiter cut and I really hate not having cruise on long trips. I am afraid if I switch it whenever I am driving, it might skrew something up.

[Bill Roberts]

ECU is a 16 bit system, sensitive to change. I would not rec. a switching unless the car is off.


Others can chime in.

[old_s13]

1) Auto ECU has no speed limiter on KA, I am not sure about SR.. but my KA definately had no limited.. took it to about 135-140 top.. takes a while, but it gets there. Mods help.

2) I wouldnt hit speeds over 120 in a 240SX unless I had good brakes AND good suspension (this includes tires). For high speeds, you need weight or aerodynamics to keep the car planted. You also need good wide sticky tires that are capable of high-speeds. Having a quality suspension helps. Z brakes or better are needed for repeated high-speed stops.

3) Mounting a switch on the speedometer signal is not a big deal, I dont think it effects the ECU in any bad way.

- Mike

[cloudpicker]

thanks again i think i know wat i should do.

[Jsquared]

i hit 125 (checked revs vs. gear graph) but was nervous as hell about it (stock brakes and Meh tires). so evidently my ECU has no speed limiter...

...which doesn't really bother me (it's not a high-speed car like my dad's 951), it's the lack of revlimiter that bugs me :mad: i hit 8100 (S-AFC says so) when one tire hit a water spot accelerating out of a corner (stupid open diff). that was like 1.5 months ago and i'm still pissed.

[Andy5]

fastest i've gone was 120. after that i got scared, car dosen't sound right "tire whined" and real twitchy, IMO its stupid to go faster than 110. But i was forced to cut my wire cause tranny thought it was in 5th gear all the time. cut it at the ECU, that way u dont have wires everywhere and its real clean looking.

[curbhuggerrps13]

well i dont knwo which yellow one...there is a yellow with a light green strip and a dark green one...i cut the light one and the rev limiter still takes place at 5000 rpms...is it the wrong one? some tell me soon cuz im about to leave to work lol

[Andy5]

i beelave its yellow and blue and has 2 silver dots every inch. "I think" use search button, tons of write ups on it.