Is there a Speed Limiter on the US Spec 95 240SX SE?

[sworxx]

I notice that when I reach high speed in 5th gear, I bounce off the rev limiter at about 6K rpm. 4th gear normally does it around 6700 rpm. I do not have a speedometer so I'm not sure how fast I'm going, (but I'd guess 120) Is there a speed limiter on these cars? If so, what's the best way to be rid of it? Do I have to flash the ECU or have it re-chipped, can I find a new ECU that will alleviate this issue? What's the best way to handle this? Thanks.

Ps. It's a race car, don't think I'm doing this on the street.

[Dattebayo]

the way you get rid of this problem is to use the SEARCH FEATURE.

Anyway, its been discussed a million times before. Speed cut at about 120 mph, rev cut exists as well.

[GEO]

automatic ecu = no speed limit 5 speed ecu = speed limiter

[sworxx]

Thanks for providing a link to the SEARCH Feature, had it been easy to find I would have started there. Did not realize it was such a touchy subject. Thanks for the info.

[sworxx]

Ok so I just did a search feature, never before have I seen a bigger collection of various solutions to this problem, none of which seem to make me feel confident that it will definitely work. Sorry to open this can of worms yet again, but it's not very clear. Here's what I found on the board.

Suggestion 1: "no its at 112.. and you cant snip a wire... you have to have the ecu re-tuned" This says to retune the ECU.

Suggestion 2: "Removing Speed Governor/Rev Limiter on 240sx Article." http://www.240sx.org/faq/articles/spdgov.htm This seems to be about the S13, says in the article it may be different for S14. Just how different is it on a KA motor?

Suggestion 3: "Unplug the 5th gear position switch...the ECU limits the revs to 5000rpm in 5th, or relies on the speed sensor to limit it to ~116 if it's connected." Ok, great, is it the same for the S14? Where is this switch?

Suggestion 4: "Greddy Speed Limiter Cut (SLC) controller Type-A universal for Nissan/Toyota vehicles. Wire in the SLC to get rid of the factory speed limiter. $69.99" A waste of money?

Suggestion 5: HKS Speed limiter Removal. See 4.

So what's the best DOCUMENTED way to do it on a 95 and above KA 240 MT????? Maybe this can help clear it up for everyone. Thank you.

[Dattebayo]

Its not a touchy subject, It just appeared that you had not tried that avenue for research yet

GEO is correct.

But if you wish to remove the rev limiter effectively without altering some other function of the computer is to get a re-flashed computer from somewhere ( http://www.jimwolftechnology.com ) or to buy a aftermarket computer for your car. (search ebay for "standalone ECU")

You can also re-chip the computer with a eprom chip, check it out at http://www.bikirom.com
Modified by 2BN_S13 at 4:14 PM 7/19/2005

[InsanityInc]

Actually, if you just unplug your 4th and 5th gear sensors, your car doesn't change operation at all. (Though if you have an S14, you don't have a 4th gear sensor). I had to leave my 4th gear sensor unplugged when I swapped in an S14 transmission, and my ECU either doesn't know or doesn't care.

[Dattebayo]

Some members reported that this action ^caused some undesired symptoms in the way their car performed.

[sworxx]

The reflashed computer seems like the way to go. Now does that disable the rev limiter or just move the rev's back? I'd prefer not to disable the rev limiter if possible, just want to get rid of the speed limiter. Thanks for clearing it up.

Yes it is an S14.

[bcar240]

From what I have gathered. If you have a KA24DE, stock for 1991+, you can clip that wire (from the faq), which will throw an error code on certain models, to get rid of the fuel cutoff at ~118mph or so. To get over the rpm limiter, which should be a bit higher, unplug the 4th & 5th sensor from the transmission. For the unplugging, I know that people with SOHC KA24Es have had problems with that, but I am not sure about DOHC.

[Dattebayo]

well i dont think bcar read the whole thread...

The reflashed computer is setup for a number of things, all of which you tell the company to put there. If you call the information number on the website, the rep will explain all the options available to you.

I will say, however, it may be in your best interest to alter a few more things with your car before investing so much money in the computer. A larger header, exhaust, intake, fuel and ignition system are needed to really get the most out of your car before a computer mod is nessesary. It wont hurt anything to go ahead, but if you change something on the car after the computer is changed, you will probably need to send it back in for another re-program (which I think is $100 each re-program session).

[bcar240]

I read it, what did I miss? I was just trying to say that that method has worked for people with DOHC engines, and that people who didn't realize it was for DOHC and did it on their SOHC engines have had problems. It is something you can try and then undo, by hooking everything back up, if it doesn't work for you. While reflashing would work, I would save that until I have a bigger reason to flash, like bigger injectors or something.

[Dattebayo]

Yeah, its just that you were repaetring everything that we had already said for the third time. SOrry, dont wanna start a war here. I am just very blunt sometimes...

[sworxx]

I already have most of the mods that I intend to do, not much more I can do and still stay in the race class. My biggest problem is running out of juice in the long straights. The speed limiter is holding me back, I'll look into unplugging the 5th gear limiter for starters. Also look for a standalone CPU. Thanks.

[drifter_for_life06]

Thanks for providing a link to the SEARCH Feature, had it been easy to find I would have started there. Did not realize it was such a touchy subject. Thanks for the info.

how do you miss it?!

its the big red flashy icon int he upper right corner!!!

this thread should be locked...there is another thread goign on right now about this very damned topic

[starkos14]

anyone have any clue what the top speed is on the auto s14? ive pushed mine to 5800 rpm but no cutoff. my speedo stopped when it hit the trip meter about 11mph past 120.

[JimmyMethod]

anyone have any clue what the top speed is on the auto s14? ive pushed mine to 5800 rpm but no cutoff. my speedo stopped when it hit the trip meter about 11mph past 120.

Depends on two things, first, it's gonna be when your power pushing your forward is matched by the force pushing you back from wind resistance. So, in a way, it's limited by how much power you're putting down. If you have enough power, what matters the drive ratio for the last gear of the AT and the rev limiter.

[lrb_2000]

you guys drive too fast... i haven't went over like 90 in my 240..

[bcar240]

anyone have any clue what the top speed is on the auto s14? ive pushed mine to 5800 rpm but no cutoff. my speedo stopped when it hit the trip meter about 11mph past 120.

I actually got bored and wrote a program for this a few months back. I got into it the other day and revised it to make it more friendly. This is what it reported on a stock S14 at 5800 rpm.

Speed: 130.624mph

For a maximum speed it reported:

Mechanical Top Speed: 157.649mph

Aerodynamic Top Speed: 145.127mph

It doesn't consider tire friction. Someone correct me if I am wrong in this assumption. But I believe that the car will travel at whatever speed the engine is spinning up to a point where the car will no longer accelerate because the drag force is equal to power the engine is producing. Anyway, it gives a reasonable approximation I think.