free (almost) timing advance "kit"

Post by **ka24de_510** » Mon Aug 19, 2002 1:04 pm

I posted this in the online mechanic section, thought it might be more accurate to post it here.

ok guys, here it is, as promised.the kit that people pay as much as $20 for on ebay...

parts:a 3.3K ohm resistor. go down to radio shack. you'll most likely have to buy a set of them, it should run about $1.29. if you can buy only one from somewhere (anywhere) besides radio shaft, a single should cost 5 cents. the colors for this resistor should be orange, orange, red, and the last color isn't all too important.

directions: bend resistor into U-shape. find your air temp sensor, it should be right next to your MAFS. disconnect the harness from the ATS. there should only be two wires attached to it. (if there are three, you've got the MAFS. put it back.) insert one lead of the resistor into one plug, and the other lead into the other plug. it doesn't matter which way. tape it all over with electrical tape so that it stays clean and put together.

that's it! make sure your loose unused harness stays out of the way of belts and other goodies. I would recommend leaving the harness in the engine bay so that you can quickly go back to stock if necessary.

other side notes:as mentioned previously by someone: try a potentiometer- cheap variable engine timing.from the inside of the intake hose, the air temp sensor looks like a little bridge attached to the side of the hose. there is a thermistor (little orangish temp-sensitive resistor) underneath the bridge, along with some other little thing. (capacitor?)

Post by **MaineExport** » Mon Aug 19, 2002 1:04 pm

I remember you saying that you were going to hook us up with this... thank you very much, you took one for the team!! Now, what exactly does this thing do? Have you had any kind of noticable increase in power? I ran my car without the intake air temp sensor attached for a little while and it ran rich as hell, and lost power.... what does this resistor do? Do you recommend we try it, or save our buck fifty!

Post by **GodDrivesA240sx** » Mon Aug 19, 2002 1:04 pm

I'm curious of the power gains myself

Post by **s14=pimpin'** » Mon Aug 19, 2002 1:04 pm

please do let us know of your results, and keep updating on a weekly/monthly basis. Thanks for sharing the knowledge man!

Post by **johnsharpe** » Mon Aug 19, 2002 1:04 pm

maineimport wrote:I ran my car without the intake air temp sensor attached for a little while and it ran rich as hell, and lost power.... what does this resistor do?

I believe the sensor converts air temp to a resistance. Buy then applying a voltage, you can measure voltage drop across or current through the thermistor and then with a look-up table, calculate the corresponding air temp.

If you run with the sensor o/c, then no voltage (or a railed voltage) gets back to the ECM and the wrong air temp is calculated.

By using a fixed resistor, the "air temp" never changes and the timing stays fixed.

I pretty sure that's right, but anyone feel free to correct me!

John

Post by **MaineExport** » Mon Aug 19, 2002 1:04 pm

That certainly makes sense, and would explain why it runs like crap with a default temp reading. I'm just curious how a fixed temp reading provided by the resistor, would be any better. Doesn't the ECU adjust timing for optimal performance as air temp changes? I'm not real sure how this type of stuff works... I'm much better off with nuts and bolts stuff!!

Post by **ka24de_510** » Mon Aug 19, 2002 1:04 pm

I haven't had a chance to run any timed 1/4s, but I am setting it up with a switch that I can flip from the driver's seat. I'm not sure if it really will work or not, but my engine seems to run fine with it attached.You're right, the ATS is just a resistor that changes value with air temp. The colder the air, the higher the resistance. I also questioned the logic of telling the ECU that the air was frigid even when it isn't. From what I saw with my sensor when it was in the freezer, its highest rating was 1.77K ohms. Of course, no air was moving over it as it would in an intake line, so that may affect it. 3.3K ohms seems awfully high. One other thing I am considering trying is attaching a 1K resistor in line with one end of the sensor plug. This would tell the ECU that the air is colder than it really is, but only by 1K, and readings would change with actual air temperature. You have to remember that the main function of ECUs is emission control. They're set up to give as much power while controlling MPG and emissions. There are gains to be made at the cost of fuel efficiency and legality. Whether this is one of them, I can't really say yet. I will keep updating as I learn.Zac

Post by **MaineExport** » Mon Aug 19, 2002 1:04 pm

Thanks ka24de_510!

I think I'm going to stop by Radio Shack today and try it out as well.

Post by **MaineExport** » Mon Aug 19, 2002 1:04 pm

Well, I did it and figured I'd report my results.

A pack of 5 resistors cost me 99 cents. It's as easy as pulling apart the wiring clip, and inserting the resistor as was previously stated.

There is little or no noticable increase in power at WOT. Maybe a VERY slight pull.. but nothing you can hang your hat on. There is, however, a slight increase in engine response on the low end. The increase is again.. nothing to write home about.. but a slightly noticable improvement. Overall, I'd say for less than a dollar you can't go wrong!! Nothing special and in NO WAY does it get you anywhere NEAR the 5 to 20 hp increase that the ebay guy claims.. but whatever small, miniscule, little gain you get can't hurt!

Moral of the story.. getting the cold air to the engine is better than tricking the engine into THINKING it is getting dense cold air.

BTW.. I've got 4 of them left.. if you want one.. the first 4 people that ask for them and want to send me an SASE.. I'll shoot one off to you for free!! Call it my 20 cents worth of good karma.

Post by **AunVoh** » Mon Aug 19, 2002 1:04 pm

you know shiping would be more then the item itself... but thanks anyway

Post by **MaineExport** » Mon Aug 19, 2002 1:04 pm

AunVoh wrote:you know shiping would be more then the item itself... but thanks anyway

If you could get them seperately you're right. But what's postage at now.. 35 cents or something... or go to Radio Shack and pay 99 cents... eather way, no big deal!!

Post by **WAbernethy** » Mon Aug 19, 2002 1:04 pm

OK, so after reading this thread I just had to try it. I drove up to my friendly Radio Shack and they sold me 5 timing advance kits for only 99 cents. I mean, I couldn't believe it. :rolleyez Anyway, driving back from the store I couln't really tell if there was any improvement. It felt like maybe there was a little more pull in 3rd and 4th in the higher revs. Not sure yet. I'll have to beat my car some more and post back in a week or so when I have a better idea.

Post by **ka24de_510** » Mon Aug 19, 2002 1:04 pm

yeah, I'd have to agree with maine that personally I can't feel much of anything. I think it might yield a tenth or so at the races, assuming it does more good than harm. I've driven the car daily since I switched it and haven't had any problems, so I'm leaving it in.

I don't recommend trying to hook up a switch; the switch and wiring running back into the cab introduce more resistance.

but yeah, before you do this, go over to 240sx.org and follow the directions on cutting a hole in your bumper. that might make a noticeable gain.

Post by **MaineExport** » Mon Aug 19, 2002 1:04 pm

Long before I tried this I had already fabricated a cold-air duct to route air from the front of the car, to under my AEM intake. I simply removed the resonator box, mounted a front facing scoop behind what would be the factory fog lamps, and ran 3" vaccum hose from the scoop into the hole from the resonator box. Granted, the cold air is only delivered as the car starts forward progress... but THAT certainly made more difference than this "upgrade" did.

In a nut shell... I would say why not try the resistor. But please don't go around telling people... "yeah.. I've got an advanced timing ECU upgrade" Because when they beat you severly in a race, you will be completely discrediting the 240sx!! "Man if that car is slow with an ECU upgrade it must REALLY suck stock".... Know what I'm sayin'

Post by **WAbernethy** » Mon Aug 19, 2002 1:04 pm

Well, after a day of driving with the "chip" lol, I feel that there is some improvement. Throttle response is noticably better and I feel that there is a little more power in the higher revs. I was concerned about the possiblilty of knocking but haven't noticed anything as of yet. Keep in mind though that I have a true CAI and water injection so these observations may be different for you. I'm almost tempted to Push my distributor tiiming ahead a couple of degrees now, just to see what it would do. I'm sure I could get away with it if I ran higher octane gas(only run 87 now). Well, let me know if I am smoking crack or what. :smoker

One other thing of note, my car seems to idle smoother now. Not sure if it had anything to do with it.

Post by **1991240xs** » Mon Aug 19, 2002 1:04 pm

WAbernethy wrote:Well, after a day of driving with the "chip" lol, I feel that there is some improvement. Throttle response is noticably better and I feel that there is a little more power in the higher revs. I was concerned about the possiblilty of knocking but haven't noticed anything as of yet. Keep in mind though that I have a true CAI and water injection so these observations may be different for you. I'm almost tempted to Push my distributor tiiming ahead a couple of degrees now, just to see what it would do. I'm sure I could get away with it if I ran higher octane gas(only run 87 now). Well, let me know if I am smoking crack or what. :smoker

One other thing of note, my car seems to idle smoother now. Not sure if it had anything to do with it.

Water Injection benefit you much? I was thinking about getting that in my car to prolong the life of the engine...benefits and negatives?

Post by **vududoc** » Mon Aug 19, 2002 1:04 pm

so what is the stock resistors rating???????? so this thing registers the air temp as being colder or hotter????

Post by **Daunttless** » Mon Aug 19, 2002 1:04 pm

You don't need water injection until you are pushing high amounts of horsepower, really its only benefit is allowing you to use lower octane fuel in a higher performance vehicle.

Post by **WAbernethy** » Mon Aug 19, 2002 1:04 pm

Honestly, the 300 bucks I spent for the water injection system would have been better spent somewhere else. Power gains were minimal. It's kinda a pain to keep up. You have to use distilled water to prevent the nozzles from becoming clogged with sediment. I have been just using tap water and cleaning the nozzles every week or two. Every now and then I'll get a gallon of alcohol from work and run it through. It seems to be more effective when you run alcohol since alcohol will cool the air better. It needs more than just the kit alone. I mean, why cool the air and make it denser if the ECU dosen't know about it? That's why I mentioned something about advancing the distributor. I may go ahead and get an adjustable FPR too since I'll need that later for the turbo. Bump up the fuel pressure and advance the timing a bit and take full advantage of the colder air that is getting in there. It will really come in handy with the turbo b/c I'll have it spray in somewhere between the compressor and the I/C thereby reducing the chance of detonation even more. Oh well, enough of my babbling. :boring

Post by **numatik** » Mon Aug 19, 2002 1:04 pm

I measured the extreme resistances of the ATS. I got around 10K ohms at extremely cold temps (in the freezer turned on high) and around .4K ohms with the blow dryer blowing on it. I bought a linear potentiometer with a max resistance of 10k ohms (couple of bucks). So far I haven't been able to test it much. I'm not noticing any big differences at idle. Hopefullty I'll have time to test it a little tomorrow.

One thing I would really like to know is how often the ECU checks the ATS's readings. Is it continusly as the car is running, or only when the car starts?

Post by **MaineExport** » Mon Aug 19, 2002 1:04 pm

I would imagine it would read the intake air temp continuously as the temp changes regularly. If it only took a reading when the car started it would always have the same lower reading (from cold start), and any warm start might change it slightly.

Post by **240sleeper** » Mon Aug 19, 2002 1:04 pm

Hi i went out to the car to do this mod and I realized I took the air temp sensor out when I installed the injen intake on my 93' hatch because there was no spot for it. Anyway now i'm sitting hear scratching my head as to where the sensor originally hooked up. I cant find where it used to plug into, anybody breifly describe where the wire is?

Post by **wanabe240esx** » Mon Aug 19, 2002 1:04 pm

the air intake sensor runs into the airbox on the back of it(facing the firewall)

as far as where it runs from i imagine the ecu, but i have yet to locate it on my friends car because i havent needed to

Post by **bruinbear714** » Mon Aug 19, 2002 1:04 pm

This is as big of a scam as Miss Cleo.

Post by **ssnnooppyy** » Mon Aug 19, 2002 1:04 pm

Okay, so sue me... I tried this little doo-hickey resistor deally bobber, and voila!! Along with the gratuitous removal of the tranny fluid pressure sensor, it actually produced a decent repsonse. I have a 90 s13 with auto trans, a cai, and stillen header, and it actually made the throttle snappier (is that a word???..as opposed to doo-hickey, etc...) and the second and third gear scratch is quite amusing next to some fart cannon equipped HoNdA. Yeah, that's right, a THIRD gear automatic trans scratch. Probably more due to the header and intake, but still, the little resistor was a plus.... anywho.... there it is, for what it's worth. To Radio Slack it was worth a wopping 95 cents. yeah.

Post by **numatik** » Mon Aug 19, 2002 1:04 pm

I tried that little trick with my 98 auto, yeah it felt more responsive but a mechanic from the dealership that I talked to said he tried it to and that it is hell on your tranny. It also set of my service engine soon light. code 112 i think it was. Is it really bad to unhook that little tranny resistor?

Post by **ssnnooppyy** » Mon Aug 19, 2002 1:04 pm

Here's what I have learned in the past 24 hours, now mind you, that is not enough time ot outdo the knowledge and abilities of a trained professional, but this info is FROM some trained professionals, so here goes: The resistor for the air temp sesnor is not crucial to the operation of your engine... it just helps. What helps even more is if the engine has a constant source of non-fluctuating temp air, so that is essentially what you are giving the engine... so it thinks. It's a little like Schwarzeneger in Total Recall... it's not REALLY cool air, but the enigne THINKS it is... it thinks, therefore it am! And the tranny mod... again, just quick asking and reading and more reading, but here goes: The job of an automatic transmission is to slide from one gear to another at specified torque/rpm/speeds... to do this comfortably, the transmission must actually work against itself to accomplish smooth fluid shifts... it actually slips gears intentionally!!!! YES!!!! So that nice cushiony slide from 1st to 2nd into 3rd is actually more detrimental on your trans than a solid thud. I know it sounds like a bunch of sales pitch hooey, but I got it from guys that have been mechanics for years, and one that is a retired nissan mechanic! It makes sense! The retiree said that with an auto versus a manual, you actually loose around 10-15% of your flywheel horses, hence the different rear gears... BUT, with the straonger shifting, due to the lack of regulated fluid pressure, you gain back some of those lost ponies!!! Now, don't take this as gospel, or even as something I whole-hertedly believe myself, I'm just passing long info... someone will surely refute or nod my info sharing.

Post by **R240NA** » Mon Aug 19, 2002 1:04 pm

numatik wrote:I tried that little trick with my 98 auto, yeah it felt more responsive but a mechanic from the dealership that I talked to said he tried it to and that it is hell on your tranny. It also set of my service engine soon light. code 112 i think it was. Is it really bad to unhook that little tranny resistor?

Yes. Unstable-Hybrids, a local shop, has thrown out at least four KA automatic transmissions into their dumpster this year alone. Running it for any length of time disconnected will destroy the transmission, guaranteed. The first person I can remember doing that, back in '96, blew hers apart at the track less than 3 months later. Yes, it does increase shifting response, but it's like shifting a manual without using the clutch, it will cause damage.

Post by **vududoc** » Mon Aug 19, 2002 1:04 pm

hey does anyone know what the sensors are on a manual....i was looking and the are 3 electrical plugs that go on there???????????

Post by **numatik** » Mon Aug 19, 2002 1:04 pm

R240NA wrote:Yes. Unstable-Hybrids, a local shop, has thrown out at least four KA automatic transmissions into their dumpster this year alone.

WOW! their hybrids are really unstable! LOL!

free (almost) timing advance "kit"

free (almost) timing advance "kit"

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