smallport 4AGE Speed sensor

[roadsailing]

Hi all, just had a poke around in the old toymods and here, didn't come up with much info.

i had my car on the dyno recently, and noticed it rev cut at 7200 RPM.

a bit of searching revealed that it should be cutting at 7700 and a speed sensor will let me have this.

now i don't want to go gluing magnets to my tailshaft, so i am going to build a square wave generator.

tell me all you know about these things, i need to know the waveform so i can copy it and "raise the ceiling"

[psychofox]

AFAIK Aussie Delivered AE92's with 4AGE with Smallports don't have a speed sensor, and rev out happily to about 7900-8000 rpm until rev cut (7700RPM is the redline on the tacho, not the hard rev limit). I transplanted one into my AE86 and has no such problems with rev limiting. I think you may be experiencing a different problem.

What computer are you running (ADM/JDM)? What loom? What coil/igniter? Any funny boxes like an MSD or something?

Hi all, just had a poke around in the old toymods and here, didn't come up with much info.

i had my car on the dyno recently, and noticed it rev cut at 7200 RPM.

a bit of searching revealed that it should be cutting at 7700 and a speed sensor will let me have this.

now i don't want to go gluing magnets to my tailshaft, so i am going to build a square wave generator.

tell me all you know about these things, i need to know the waveform so i can copy it and "raise the ceiling"

[roadsailing]

JDM ECU as far as i know, smallport igniter, 4AFE or something coil.

my wiring diagram (which i used to wire the car) has a pin for a speed sensor, and it is an easy thing to hook up. i just need to know the frequency and voltage of the signal.

loom is a combination of JDM and aust AE92 looms, spliced together.

also, toyota tachos are notoriously innaccurate, i always thought mine did rev to 7700, but the RPM trace says differently.

[Garth AE86]

ae86 dash tachos are terrible for this

im running an safc2 so it decides the rpm cut
the ecu doesnt know any better anymore

might wanna source one if its less hassle?

[roadsailing]

not really, as i can build one for about 10 bucks. i could use a proxy switch or magnet and reed/hall effect switch on the tailshgaft simply for possibly less.

if i was going to buy an SAFC i would put the money towards an autronic ECU and be done with it!

i just need to know some characteristics of the waveform. might have to measure the signal in someones car with a 'scope, but i really cant be bothered.

edit:

http://www.offroadpakistan.com/downl...%20Sensors.pdf

[Garth AE86]

fairy muff then!

good luck!

[The Last Streetfighter]

http://www.twincam.org/forums/index....wtopic=397&hl=

[roadsailing]

thank you streetfighter, thats what i was after!

[The Last Streetfighter]

No Problemo.
I am confused, though. Don't you just need to connect the 4P terminal to the right pin in your ECU to get it to work?
I had no tacho (and no speed sensor) for a few months when I got my silvertop. But then I got an SX cluster and AK just wired it up including the sensor signal.

Trev

[roadsailing]

yeah, i'll have a look for that point on my spare cluster.

thing is, i don't want the 180km.h speed cut, so if i just feed it a constant wave, it will be a speed cut defender too.

might even rig up a lying box, that reads the signal form the tacho speed signal and divides it by two.

[pro_k]

ae86drift - How does your safc2 change the factory rev limit? Is there a function on it to change rev limit? Mine cuts at 7200 with safc.

shinybluesteel - Would like to know how this works for you. My engines still building power at 7200 as it hits limiter. Would like to change this before spending $$ on an Autronic.

[roadsailing]

yeah, mine started dying in the ass at around 7200 anyway - i put my car on after yours on saturday (after watching adam paint things for 3 hours) and made 104 hp.

if mine works out OK i'll make one for you too.

[pro_k]

Didnt know this was you man!

You got to run it

Let me know how you go. Shall try this before going aftermarket.

Thanks for the offer

[roadsailing]

haha, thanks again for bringing the seat out.

I wasn't aware that the bluetops had a speed signal, it is possible that the dyno RPM reading was out (but our cars would have different diff ratios so i doubt it)

will post back when i work it out.

[WHITCHY]

have you tried running the car with a stock aus ECU?
I have a bigport from an AE82 in my AE86 and with the AUS ECU it hits rev limiter at about 7400 and then when I put a JDM ecu in I was told it would make it go all the way to 7700, but it did what yours is doing and it cut it back to 7200!
When I asked about it I was told it was cause of the speed sensor,but then the ECU got fkd by water so I never got a chance to fiddle with it!
Please keep the thread updated, and if it works out would you consider making one for me? I will pay your for your troubles!
Thanks heaps.
-Whitchy-