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Discussion Starter · #1 · (Edited)
EDIT:

I have a 09 Civic SI. I am currently building this car for a circle track. I have searched this forum and most others but there is not a lot of actual details or exactly what is needed to do this conversion. I have gathered as much information as I can from the interwebs.

NOTE: With this conversion you can NOT use your stock clusters / ECU and so on. This is only intended for the gutted track cars or whatever you want to use this information for.


What is needed to convert from DBW to a Throttle Cable set up.
I have found a majority of what is needed.

Any year RSX Type S Throttle Body.
RBC Throttle Body Adaptor Plate.
Any Year RSX Throttle Cable.
02-04 RSX Type S (PRB) ECU with K-Pro.
Stand Alone Engine Harness
(personally I like Ry-Wire budget harness).
Any year RSX Gas Pedal.

Now with this conversion, I will have some issues and will update this thread and also with photos as I start the build process. (I am currently still gutting the car) now with the gas pedal there will be some cutting, grinding, welding and so on to make this work as the 09 SI have the gas pedal mounted to the "floor" area and not on the firewall like normal cars have.
 

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Discussion Starter · #4 ·
Figured I would post the progress of the build. I have everything almost taken apart. Rest of the wiring to be pulled out and fuel tank.

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Have you looking into what modifications you'll need to make to the wiring harness to get the TPS to talk to the ECU?
 

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Discussion Starter · #6 ·
Well I thankfully have a friend that knows how to figure out the wiring portion of what is needed. I do believe the RSX Ry-Wire engine harness with the PR8 ecu will already do that if I'm not mistaken.
 

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If I understand it correctly, you have a 09 Civic SI drivetrain (K20Z3).
You want to convert it to cable throttle.
You're using a RSX ecu with Kpro, a RSX cable throttle body, and the K20Z3 engine harness.

If that's correct, to make it work, you just have to wire a TPS to the Kpro -- unless I'm missing something.

TPS Signal (TPS) wire to A15 in the ECU (RED/BLK wire)
TPS 5v (VCC) wire to A20 in the ECU (YEL/BLU wire)
TPS GRD (SG2) wire to A10 in the ECU (GRN/YEL wire)

From there, the ECU will see the TPS.

HOW you connect those wires can be done in a variety of ways:
  • Find the DBW wires, trace them back to the ecu plugs, depin and pin to the TPS plug for the TPS you're using
  • Run new wires between TPS and A plug.
  • Whole new engine harness with the wires already incorporated for the correct plug.
 

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Discussion Starter · #8 ·
If I understand it correctly, you have a 09 Civic SI drivetrain (K20Z3).
You want to convert it to cable throttle.
You're using a RSX ecu with Kpro, a RSX cable throttle body, and the K20Z3 engine harness.

If that's correct, to make it work, you just have to wire a TPS to the Kpro -- unless I'm missing something.

TPS Signal (TPS) wire to A15 in the ECU (RED/BLK wire)
TPS 5v (VCC) wire to A20 in the ECU (YEL/BLU wire)
TPS GRD (SG2) wire to A10 in the ECU (GRN/YEL wire)

From there, the ECU will see the TPS.

HOW you connect those wires can be done in a variety of ways:
  • Find the DBW wires, trace them back to the ecu plugs, depin and pin to the TPS plug for the TPS you're using
  • Run new wires between TPS and A plug.
  • Whole new engine harness with the wires already incorporated for the correct plug.
Basically yes. I am not using any of the stock wiring as there is about 40 lbs of wiring and really just a complete mess. The chassis harness had broken clips and all the rear wringing in the car was cut for the taillights. Also front headlight wiring was also cut before I bought the car. So that kind of determined me to not want to have any of the stock wiring in the car and less of a headache to deal with.

I will be getting a stand alone engine harness and not use the stock engine harness. I will have switches for fuel pump (fuel cell), push button start to get rid of the stock steering column. Mind you this is a circle track car and the less things in the car the better.

I do already have the RSX components needed to swap to a throttle cable set up. I am only missing the engine harness right now and I am looking into what engine harness is best for what I need.
 

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Discussion Starter · #9 ·
I did forget to mention the ry-wire or whatever engine harness i will be getting will be for a RSX type s and that will have the TPS sensor. But if I were to use the stock engine harness then yes, I would do the repin to make it work.
 

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I'm curious why you're getting rid of the DBW. I'm going the opposite way in my race only K24 EK4. DBW will make throttle response infinitely more tunable, and can be used for traction control (where legal) as well as having separate mapping for wet / dry tracks etc.
I'm running an Emtron KV-8 ECU which lends itself well to DBW mapping.
 

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Discussion Starter · #11 ·
I’m running circle track racing. So with all the wiring gone I can lose 40-50 lbs of all the stock wiring and being able to get the car light as possible. That’s the main reasoning to switching.
the track rules are not very favorable to the k20s but I’m gonna do everything I can to make this car the fastest it can be.
rules wise is stock only cars with weight limits and so on.
nowif I were to build this car to run as a road course type then I’d leave the dbw.
with me being able to swap to a throttle cable then k-pro will do much more for what I personally need.
 

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I’m running circle track racing. So with all the wiring gone I can lose 40-50 lbs of all the stock wiring and being able to get the car light as possible. That’s the main reasoning to switching.
the track rules are not very favorable to the k20s but I’m gonna do everything I can to make this car the fastest it can be.
rules wise is stock only cars with weight limits and so on.
nowif I were to build this car to run as a road course type then I’d leave the dbw.
with me being able to swap to a throttle cable then k-pro will do much more for what I personally need.
Nothing quite like the feel of a nice tight throttle cable On a k motor 👍 this is a cool idea, I bet a lot of 06-11 race-only chassis are cable driven. I don’t care for the ecu interference between shifts.
 

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I feel like I would get more feeling out of pedal response with the cable then I could with the DBW.
I have never owned a DBW. I do wish that Honda made a drive by cable TB in 64mm.
 

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So with all the wiring gone I can lose 40-50 lbs of all the stock wiring
Confused... switching to cable throttle body won't save you 40-50lbs in wiring.
I'd be surprised if the entire chassis and engine harness weighs at 50lbs.

The real benefit is simplicity -- Removing all of those components your car no longer has makes it easier to troubleshoot.

Even the minor weight savings of switching from DBW to DBC could be overcome by just taking a massive shit before going out for the race. Or run the race with exactly the amount of fuel needed so you pass checkered on vapor, since gas is 6lbs per gallon.
 

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Discussion Starter · #18 ·
Confused... switching to cable throttle body won't save you 40-50lbs in wiring.
I'd be surprised if the entire chassis and engine harness weighs at 50lbs.

The real benefit is simplicity -- Removing all of those components your car no longer has makes it easier to troubleshoot.

Even the minor weight savings of switching from DBW to DBC could be overcome by just taking a massive shit before going out for the race. Or run the race with exactly the amount of fuel needed so you pass checkered on vapor, since gas is 6lbs per gallon.
Well yes it's around 50 pounds of wiring with the fuse box and so on that I won't be needing. But regardless weight rules are left side percent + HP. So with this car, I'll be around 50% left side weight. By removing majority of the wiring and useless things I need to make this car go vroom vroom, it will be beneficial to troubleshoot and that is the main reasoning.

When I bought this car it was a street car and the guy who owned it didn't know how to wire anything correctly so there was a lot of sub wires and cut / damaged wiring throughout the harness. No signal to starter, fan didn't turn on when it got to temp. It was a mess so rather then replace or troubleshoot the entire harness, I'll go the route with DBC and throw a little money at it by swapping what I need.

With the gas can be a little tricky too. Sometimes tech will make us go across the scales before or even after a race. Playing with the gas weight is a little difficult because know one ever knows until it happens. I normally am very close with playing with the gas to make weight but I'll be adding a 8 gallon fuel cell so I can get some weight in the rear of the car to make it loose. These cars hate turning unless if they are loose on the track.
 

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Discussion Starter · #19 ·
Update as of 12-3-2021. Getting ready to prep for welding the roll cage in next week. Once that is done I'll be removing the ABS and making new brakes lines to both front wheels and brake master.

I do have a question if anyone has done a EK (96-00) proportion valve? It should work all the same. I'm not sure about the brake master on if I should swap it to a 96-00 one or just keep the one in it now. I think as long as I take out the abs and use a EK prop valve and run new lines where I need, then everything should be okay. Once that is determined, new bushings / suspension components are going in or ready to be going in until the motor/transmission is ready.

Wheel Tire Car Vehicle Motor vehicle
 

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i'm going to recommend going to the A2 oil pump and a baffled oil pan (9th gen is compatible with a custom mount)... my local short track guys let their engines sing for a long time and i dont trust the balance shaft oil pumps.
 
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