K20 Fit How To Discussion

[gettinafit]

Originally Posted by 03DSM-RSX

actually, it in fact DOES split. i have found that the MAP, ECT, and IAT sensors are affected by splicing the wire and splitting it to 2 ecus. I am currently finding ways to get a clean, fresh signal straight from the sensor instead of splicing it. I will certainly let you know when i find out.

I am running a dual ecu setup and currently working on a new R&D project for Hondata. I assume you already have Hondata Kpro on the RSX ecu? Once you have the electrical things able to turn on, you can check the KManager software and see what sensors are needed.

so at this point, your FIt ecu is controlling: multiplex, a/c...and what else?
RSX Kpro ecu should be controlling everything else, including OBD2. Although you can leave the "K-Line" from the Fit ecu tapped with the RSX's K-line to be able to diagnose both ecus. but when u go in for inspection sometime in the future, cut the K-Line from the Fit ecu. (K-line is the OBD2 comm line)

Originally Posted by 03DSM-RSX

i can provide pics of me testing it and showing you the before/after "splitting" the signal and its signal values. I can get them up monday when i start testing various methods. (if it doesnt rain) And yes, there ARE resistors that stem directly to the IAT/ECT sensors.

For safest measure, you dont need to give the Fit ecu the ECT reading. If the signals are not accurate, your ECT will be reading a lot lower than it is actually, and the engine will constantly be working itself to get to warmed up temp of ~180. Resulting an overheating condition that you wont know about. (this is wat i DONT want to see happen) You can simulate ECT/IAT values with the use of different resistor values for the Fit ecu to make it think its "ready".

Again, this information was stated in my reports from the last project i worked on and is confirmed by Hondata. Although Hondata is experimenting by removing those certain resistors and/or changing resistor values on the ECU itself to amplify the signal enough to provide accurate readings between 2 ecus.

I believe my buddy is going about it the second way as hondata is. he has my makeshift harness now and is pluggin things up and testing voltages. SO as for now, i'll be worrying about a/c lines and waiting on that stuff to come back as well as the header situation.... (non-existant)..... HASPORT HELP!! JHPUSA HELP!!! (Both have K20 fit's and prototype headers not released yet....)

[jtallen123]

Originally Posted by 03DSM-RSX

i can provide pics of me testing it and showing you the before/after "splitting" the signal and its signal values. I can get them up monday when i start testing various methods. (if it doesnt rain) And yes, there ARE resistors that stem directly to the IAT/ECT sensors.

For safest measure, you dont need to give the Fit ecu the ECT reading. If the signals are not accurate, your ECT will be reading a lot lower than it is actually, and the engine will constantly be working itself to get to warmed up temp of ~180. Resulting an overheating condition that you wont know about. (this is wat i DONT want to see happen) You can simulate ECT/IAT values with the use of different resistor values for the Fit ecu to make it think its "ready".

Again, this information was stated in my reports from the last project i worked on and is confirmed by Hondata. Although Hondata is experimenting by removing those certain resistors and/or changing resistor values on the ECU itself to amplify the signal enough to provide accurate readings between 2 ecus.

Sounds like fun trying to balance the circuit impedences to get the proper voltage range.

[03DSM-RSX]

Originally Posted by gettinafit

I believe my buddy is going about it the second way as hondata is. he has my makeshift harness now and is pluggin things up and testing voltages. SO as for now, i'll be worrying about a/c lines and waiting on that stuff to come back as well as the header situation.... (non-existant)..... HASPORT HELP!! JHPUSA HELP!!! (Both have K20 fit's and prototype headers not released yet....)

Well, the resistors i'm talking about reside within the K-Pro daughterboard itself. But be sure to keep attention on the ECT. GL! Dont hesitate to give Hondata a call for help. Or, if they're too busy, PM me.

As for a/c lines, have you looked into using the EP3 a/c line?

[03DSM-RSX]

Originally Posted by jtallen123

Sounds like fun trying to balance the circuit impedences to get the proper voltage range.

lol, very much. i was surprised by the different behaviors the car and transmission exhibited when given different values. Never knew how big the affect was these little signals do.

Having a laptop showing real-time values as you're making different combinations helps a TON. You can also use an OBD2 reader.

[jtallen123]

Originally Posted by 03DSM-RSX

lol, very much. i was surprised by the different behaviors the car and transmission exhibited when given different values. Never knew how big the affect was these little signals do.

Having a laptop showing real-time values as you're making different combinations helps a TON. You can also use an OBD2 reader.

Yeah it's quite interesting to see what they use the signals to do, and very interesting to try and reverse engineer it.

[jtallen123]

Originally Posted by claymore

Guys it's very simple Ohm's law voltage does NOT change if the circuits are connected in parallel however amperage does. Where is our resident electrical engineer Arteitle when you need him??? And how does a resistor "Amplify" a current??

And I for one would love to know how the ECU would make the engine work harder "to get warmed up" if a sensor had a wrong reading???

Hence my first post on the subject. But I've not seen the ciruit in question either.

I also would be curious to see what they do with all the sensor inputs in the ECU, but you do want to make sure it get's the input it's expecting.

[03DSM-RSX]

quote claymore

removing the resistor, in a way, "amplifies" the signal back to the full signal. and no, the resistors are not wired in parallel, but in a series. Parallel only works if you have one resistor with the exact resistance needed. (in the case and subject we're on)

Ever notice how you first start your engine and rpms are higher than it is when its warm? its "working" harder to get it to operating temps faster. With the ecu seeing that the temps are not 179-185, it will continue to work (higher rpms) to get it to that temp. In a normal car, you see idle is more quiet and smoother as the car is in operating temps. Oh claymore, regarding your Spoon/Mugen low temp thermostats, please read:
Tech - Thermostat

I've been there and done that. Affects more so with an automatic trans, torque lock-up does not engage until temps are within operating temps. Result with no lock-up=higher cruising rpms on the highway, generating unnecessary heat.

Any questions?

You can also check your helms/service manual. it will show all the systems that are correlated with ECT readings and why the ecu requires so many sensors and inputs.

[gettinafit]

Originally Posted by 03DSM-RSX

Well, the resistors i'm talking about reside within the K-Pro daughterboard itself. But be sure to keep attention on the ECT. GL! Dont hesitate to give Hondata a call for help. Or, if they're too busy, PM me.

As for a/c lines, have you looked into using the EP3 a/c line?

Yes Hasport told me that they used the EP3 hatch suction side hose abd fabbed it to fit the stock fit hose. That and relocating the other line.

And you guys sure are getting technical! Computer stuff is not my forte!

[03DSM-RSX]

um...i dont think i stated that using resistors gives a higher voltage. if i did, then yes, i'm mistaken. i used the term "amplify" merely to illustrate that the signal gets strong enough to split the 2 signals and gives 2 ecus an accurate ECT reading.

oh i didnt state the high rpm cruise in relation to the thermostat, no. it was relating to ECT temps. So high rpms at idle is not working harder than low rpms? i said the engine works harder to get the engine to warmed temps and to ready the catalyst system, not the way you said it.

Why higher rpms/load during cold start? i would tell you EXACTLY why, but we'd deviate from the topic in this thread. And i'm sure u would know more than the Hondata engineers do.

[signalpuke]

Swap is looking good man.

[gettinafit]

Originally Posted by signalpuke

Swap is looking good man.

Thanks, sometime next week I hope to have the wiring done and the computers back. Will take pics next week!

Then All that is missing is of course the header!

Maybe I'll put things in if it doesn't interfere with the placement of the header. I will have to find out.

[jbrisson]

Originally Posted by gettinafit

I believe my buddy is going about it the second way as hondata is. he has my makeshift harness now and is pluggin things up and testing voltages. SO as for now, i'll be worrying about a/c lines and waiting on that stuff to come back as well as the header situation.... (non-existant)..... HASPORT HELP!! JHPUSA HELP!!! (Both have K20 fit's and prototype headers not released yet....)

You should talk to R-Crew about making you a header. There are a lot of companies doing it. It'll cost you some coin though. My SSR (Six Sigma Racing) header was $1100, I think, but worth every penny.

[gettinafit]

Originally Posted by jbrisson

You should talk to R-Crew about making you a header. There are a lot of companies doing it. It'll cost you some coin though. My SSR (Six Sigma Racing) header was $1100, I think, but worth every penny.

THey would need either the dimentions or the vehicle itself! My only hope Long Island's Unorthodox Racing (pulley manufacturer) and a o.k. weld job! Or just wait until someone gets a hold of a prototype or a k20 fit on the West coast into one of those shops.

[jbrisson]

For some reason I didn't even look at your location...I will check around. I know there's somebody relatively close to NY or at least the mid-atlantic who does custom header assemblies who might be able to help you out.

[Raaaaaaaaaay.]

Anyone read the issue of Sport Compact Car? (dont know issue) HASport's K20 Fit. Wow, huge disappointment. Theyre testing it with a stock 06 Civic Si. The Fit only ran about 1-2 secs faster than the stock Si. Hahahahah!!!!

They used the wrong motor and trans in that Fit. That Si motor is junk.

[gettinafit]

1.5-2 seconds faster is a big improvement though. NOTE: the hasport Fit is using the K20Z3 from the Civic SI and electronic Drive By Wire.

My K20A2 with cable accel. and Hondata should be nice! Just waiting on the wiring! SOmetime soon.......

[Raaaaaaaaaay.]

Originally Posted by gettinafit

1.5-2 seconds faster is a big improvement though. NOTE: the hasport Fit is using the K20Z3 from the Civic SI and electronic Drive By Wire.

My K20A2 with cable accel. and Hondata should be nice! Just waiting on the wiring! SOmetime soon.......

Its not a big improvement. They were going against a fully stock full weight Civic Si.
The Fit dynoed 209whp. Wheels, tires, suspension, less weight and only a 2 sec difference. I expected more. Maybe the K20 Fits are only straight line cars. *shrugs*

And yes I know its the K20Z3. Thats why I said it was the wrong motor. Its not a real K20 IMO, built in Canada.

[loud_tiger]

Originally Posted by Mx6GT89

Its not a big improvement. They were going against a fully stock full weight Civic Si.
The Fit dynoed 209whp. Wheels, tires, suspension, less weight and only a 2 sec difference. I expected more. Maybe the K20 Fits are only straight line cars. *shrugs*

And yes I know its the K20Z3. Thats why I said it was the wrong motor. Its not a real K20 IMO, built in Canada.

2 second difference in what?

[Raaaaaaaaaay.]

They were testing them on a road course. New Civic Si vs a K20 Fit.

[gettinafit]

Originally Posted by loud_tiger

2 second difference in what?

But it does great 1/4 mi straight runs! Probably in the low 13 sec range!