Techsalvager

Has anyone tried the DIYautotunes new cas wheel in place of the stock 4+2 cas wheel?

miatauser884

iTrader: (11)

I bought one, then found out both my CASs were not optical even though one of the covers suggested it should be optical.

Techsalvager

Interested in selling it?
I know for sure mine are optical since I've opened both mine.

miatauser884

iTrader: (11)

sure, send me a pm to remind me tomorrow, I'll give you a good deal on it.

WestfieldMX5

Still triggered off the camshaft, so what's the benefit?

Techsalvager

I would think a higher resolution if the sensor can handle the extra slots without issues.
so more percise understanding of where the crank position is.

Braineack

iTrader: (62)

It's supossed to provide more resolution since there's, what, 12 teeth instead of 4.

edit: what tech said.

richyvrlimited

iTrader: (1)

More resolution, but will you actually gain anything from it? you'll still suffer from spark jitter, possibly worse due to the amount of smoothing less resolution can give.

Techsalvager

Personally I would be hoping to see less spark scatter, but I won't know for sure until I get my hands on one and find out if its possible to use.
I figured with knowing better crank position there would be less timing error

miatauser884

iTrader: (11)

Did you want it? I think I sent you a pm

WestfieldMX5

I still don't see the point. The belt has several degrees of slop and is what causes the timing error. I doubt you'll see any measureable difference from going to a 12 disc.
Still, I hope I'm wrong and am very interested in seeing before and after measurements!

Braineack

iTrader: (62)

All i know is, that when I went from MSII to MSIII, the resolution was so much better, that i was barely able to first idle the car; it turned out I forgot to tightening my timing belt a few months before over winter and that the MSIII, all things being equal, was more accurate at reading the signals and the fuel/spark timings were random and off.

So I'm assuming that being able to get a more accurate picture of the crank angles would just make your fueling a touch more efficient.

Techsalvager

Yes I want it, got to get money moved over, I'll send you payment today.

Techsalvager

on ms2 I noticed a bunch of scatter even at idle compared to my stock ecu which was rock solid. I think its also a partial software issue.

bcrx7

iTrader: (5)

I just ordered one, so we will see. Pretty good price and nothing to loose really. It should give way better resolution in theory.

Techsalvager

Nice looking rx7s do you have any links to info about them?

Joe Perez

iTrader: (8)

That particular wheel was designed to replace an oddball Nissan 24-1-1 wheel for which native software support was not available in the MS1 and MS2 code.

In other words, the design intent was not to improve accuracy on 4G63 cars, it was to allow 24-1-1 cars, which could not previously use a Megasquirt without custom-fabricating a crank trigger, to do so.


If you want better spark accuracy, buy TSE's 12 tooth crankwheel.

Techsalvager

Its a 360 hole optical wheel that the diy cas wheel replaces that would be better all together if the older MS's supported it.

richyvrlimited

iTrader: (1)

360 teeth will just waste processor cycles reading them all, pointless.

The TEC lineup as one of the most accurate ignition systems available and it only uses 60 teeth, tell me why more would help?

bcrx7

iTrader: (5)

Well the one in the middle was crashed a couple of years back and we rebuilt it. I will post some picture and info in the build section soon. The one on the left (1st gen) is getting a restoration with a BP engine and big turbo. I will add info on that in the same build thread. This is all if I have time!

If I use that crank trigger, can I still use the CAM part of the old CAS for my cam trigger input or do I need a 99 cam sensor?