BLUE TII

iTrader: (9)

I am looking for help finding out the true specifications of a Knight Sports 4BEAT ROM tuned ECU I have.

I put it in with a jumper harness and the four wires cut that JDM ECUs don't use (like a Power FC install) and it idles/runs/revs fine, but has SUPER hesitation/cut out around 5psi boost.

It seems it was tuned for much larger 2ndary injectors and is running very lean when they are supposed to come on or the 2ndary injector drivers are burnt out. I cannot think of anything else to cause this.

If anyone knows or has heard of anyone that might be able to help find these specifications, any information is appreciated.

Narfle

iTrader: (16)

Frankly, ill be surprised if you get any info. Were not really good about jspec ecus. Tried reaching out to knightspot?

BLUE TII

iTrader: (9)

I did email Knight Sports with the picture and simple questions in English, but no reply. I will try again in (poor) Japanese. Hopefully that amuses them enough that they answer.

I seem to remember someone on the forum once saying they could get the specs on these 4BEATS, but haven"t found that post again yet.

I am trying to cajole the seller into finding the specs for me since he is in Japan/should have connections and sold it advertising a false spec, but no luck so far...

Narfle

iTrader: (16)

I had an old RE Amemiya ECU that almost ran OK. Ended up going with the tried and true pettit unlimited.

j9fd3s

iTrader: (3)

just looking at the knightsports site, they offer single turbo and sequential ecus, with a bunch of options.

http://www.knightsports.co.jp/blog/4BEAT-FD.pdf

Speed of light

iTrader: (8)

The injector drivers are actively current limited and not likely to be damaged.

Mahjik

iTrader: (1)

If it's still a stock based ECU, you may be running into a problem with the fuel thermosensor line. IIRC, it's not in the same location on the JDM series. Most owners run into this using a JDM wiring harness with a North America ECU. It seems you may be running into in the reverse:

https://www.rx7club.com/3rd-generati.../#post11393062

Something else to check...

BLUE TII

iTrader: (9)

Thanks Mike! Yep, I found the order form and went to the trouble of translating it before I bought a used ECU, but I still couldn't figure out the "T", "M", "B" options shown on the ECU's spec sticker from it.

I found the pin outs for both the US N3A1 ECU my car came with and the N3A7 the 4BEAT is based off.

1U, fuel thermosensor is the same.

To use a stock JDM 8bit ECU its just the same four 3J, 4F, 4O and 4P pins /wires you have to remove like when you put in (the JDM based) 8 bit Power FC.

Seems Knight Sports used to do the old Bosch 1600cc and sand block resistor hack for bigger injectors just like in the US. Its probably set up for that, but it would be nice to verify.

Jobro

iTrader: (2)

T - Turbine? N for Normal?
M - Muffler?
B - Boost? N for Normal? N for no boost controller?

I was interested to see what all the options where so I spent some time using google translate.

Please keep at this and get it working, I'm very interested to know how it turns out!

BLUE TII

iTrader: (9)

Okay, here is the update with good news!

I contacted all the vendors I could find that sell/have sold Knight Sports parts and ended up going through Auto-Style USA.

While I did not find the true specification of the used ECU I bought I went ahead and just ordered through Auto-Style USA a ROM reflash to my specifications.

Very fast shipping back and forth.

I plugged in the freshly ROM tuned ECU and it runs and drives great, even though I still have my stock ECU limited parts on the car still. With stock intake and all its pretty rich over 7,000rpm and mega flame throwing rich between 8,000-9,000rpm.
Never had the car idle and drive so smoothly- rotaries love a rich tune.

I basically had it tuned to the maximum of the stock injectors.

Knight Sports assured me that their ROM tune still employs stock knock sensor feedback.

BLUE TII

iTrader: (9)

Here is the order form I made out.

To run a JDM ECU you just disconnect the same four wires as you would with a Power FC. I put connectors in the Knight Sports EBC III jumper harness to make it easier to switch back and forth between USDM and JDM ECUs.

Narfle

iTrader: (16)

Wow. Very cool. Can they get new KS ecus tuned to spec, too?

BLUE TII

iTrader: (9)

Well, through Auto-Style USA you can arrange purchases and services that would be available to a Japanese consumer.

You are paying JDM prices plus their commission, so some things will get prohibitively expensive.

I believe the only three services Knight Sports offers for 8Bit ECU are-

- Specification change / upgrade KDD-19393 ¥ 26,250 ¥ 25,000 ~ '95 / 11

- Specification change / upgrade name change KDD-19394 ¥ 36,750 ¥ 35,000 ~ '95 / 11

- User name change KDD-19395 ¥ 10,500 ¥ 10,000 ~ '95 / 11


If you are getting a daughter board put in a stock ECU and ROM tuned you might as well start with the newer/better 16Bit ECU and use the Knight Sports adapter harness.

- Basic / Normal turbine KDD-19401 ¥ 168,000 ¥ 160,000 '95 / 12 ~

- Basic / 420 turbine KDD-19402 ¥ 168,000 ¥ 160,000 '95 / 12 ~

- Advance / Normal turbine KDD-19403 ¥ 168,000 ¥ 160,000 '95 / 12 ~

- Competition KDD-19404 ¥ 189,000 ¥ 180,000 '95 / 12 ~

- Specification change / upgrade KDD-19493 ¥ 26,250 ¥ 25,000 '95 / 12 ~

- Specification change / upgrade name change KDD-19494 ¥ 36,750 ¥ 35,000 '95 / 12 ~

- User name change KDD-19495 ¥ 10,500 ¥ 10,000 '95 / 12 ~


As you can see chipping a stock ECU costs $1,638.17 plus commission so not many people would do that when you can find really cheap already chipped JDM ECUs on Ebay and pay the $376.27 to get it flashed to your set up and registered in your name.

You could pay just the $107.50 registration fee to discover the specifications to see if it will work for your set up and then $268.76 to have it flashed if not.

My goal was to try and have more reliability than a stand alone by leaving the stock knock control in place as I get bad gas at the pump often (and it is the most expensive gas in the nation- gotta love monopolies).

Still, I was cautioned I should run the equivalent to JDM 100 octane RON with this tune (13.5psi) which would be US 95-96 octane AKI.

That would be my usual 1 bottle Lucas octane booster to 10 gallons. I can use a low boost default setting on my Knight Sports EBCIII in case I don't have the Lucas.

Well, that is the plan.

Narfle

iTrader: (16)

Is that what you're doing? Running a 16 bit ecu with an adapter harness? Also surprised you're winding out to 9k lol.

BLUE TII

iTrader: (9)

No, I picked up a cheap chipped 8Bit ECU on Ebay.

Yes, it pulls pretty good to 9,000rpm in lower gears with the intake on it now. The increase redline was mainly so I could hold gears at autox. It does 47mph in 1st and 81mph in 2nd now.