No Rev limiter?

[biggadubuti]

i have a 1989 coupe, with the rb25. i installed everything myself, and everything is fully functional. the car runs great, pulls very hard, but i have no rev limiter. i am using the silvia cluster, the tach works, and i am pretty sure it is accurate, because of boost and idle. if i dont let off, it would rev to 9000 or even higher. i am pretty sure the stock one for 25 is like 7000 or something. i am pretty sure it is a stock ecu, no stickers or anything. does anyone know of a solution for this?

[Yellow4g63]

Thats cause your running the Stock KA/SR tach.

[biggadubuti]

well why would that do anything? the signal goes directly into the ecu, then it comes out into the dash harness of the skyline and that is the wires that i am using to run the tach. how would i fix the problem, i already tried to stuff the rb cluster in there, but i def dont think it will fit into a S13.

[Phax]

You have to calibrate your tach. I have an S13 SR20 with a type 62 ECU and the 9000 RPM JDM tach. It is 500 rpm off across the entire rev range. You need a secondary instrument to read your REAL engine RPM speed, which will let you know how much to recalibrate the tach. There is a little plastic screw on the back, that you basically have to rip apart the whole dashboard to get at. But if REALLY want an accurate tach, you can do it.

[frosted flakes]

actually no,

it is EXACTLY 1.5x higher. think about it. You are getting a signal from a 6 cyl engine instead of a 4 cyl. So you are getting EXACTLY 1.5x more signals coming in.

So if its reading 9000rpm on the tach thats about 6000rpm on the engine. and yes these engines do have rev limiters. my rev limiter is about 7500rpm at the engine (not the tach)... calibrate your tach.....

[Wulfgang]

1.5x is theoretical. Mine reads at least 2x higher at idle (S14). These things aren't exact because they aren't digitally controlled. Also, as others have proven, you can calibrate your tach to read correctly at idle, but then it will be off at 5krpm. So yes, both Phax and frosted flakes are correct, which sucks for us. There are a multiplier and offset that both come into play.

Anyway, bottom line... you must calibrate your tach to get a reasonable reading. If you need a closer reading, then you'll either need the RB tach or an aftermarket tach or you will have to make up a simple digital converter (using an Attiny or something like that) to convert the pulses.

[wga240]

And even once your tach is calibrated you may not have a rev limiter. I'm using the RB tach in my 240 cluster so I know it's at least close to accurate, and as best I can tell I either have no rev limiter or its way too high to be of any use.

I had a stock looking ECU until I opened it up and saw an Advance sticker on the inside, which was the logo for some obscure japanese tuning company: http://advance-jp.com

[biggadubuti]

thanks for the info, i still dont know if it has a limiter or not, ill try to poen mine up too to see.

[biggadubuti]

it is a stock ecu, no stickers on the inside, i could see about the whole calibration thing, but the car still makes boost at all the right times. full boost by about 3500, i have a boost gauge, reads 7-8 pounds. when im on the freeway, it reads about 4500, when i punch it it has boost instantly. when do you guys make boost?

[Yellow4g63]

Trust me your tach is off. U will hit rev limit when the needle goes past 9k on your tach. My friends runing the stock SR tach and thats how far it goes before it hits the limiter.

[biggadubuti]

i still dont think i have a rev limiter. i put it in 3rd and kept my foot planted, the tach went all the way around to the time adjuster, the engine revved a little higher, then it stopped and made a wierd sound, i dont know if it was the valves floating, or detonation or what. How does the rev limiter sound, i know on like a honda or something, the car will just stay there and it is very obvious. let me know what yours does.

[Yellow4g63]

No it's not like a honda. It's a soft touch limiter not violent like a honda's

[biggadubuti]

so what i experienced, prob, was the rev limiter. my car still has open turbo, so maybe it just sounds higher than it really is, i sure hope it isnt messing up my engine, i am going to get a APexi rev speed meter, just cause, cause the speedo doesnt work either with the SR tach. does anyone know how to make it work? i have tried to wire it up many different ways, but no go.

[Yellow4g63]

I haven't even touched my car in 2 weeks. if you used your ka lower harness then u just plug in the ka speed sensor to the harness.

[goofynick6]

I'm guessing I'll have to use an autometer tach or something, because I don't wanna calibrate it for just lower rpm's, I wanna be able to know where my revs are..etc. I might see if I can pull out the stock on and put in an autometer unit right in the dash.

Nick