Intake Manifold and Pulleys


    Hi! More progress on the K Swapped RX8 underway :) In this post, I would like to go over how to fit an S2000 intake manifold into the engine bay and onto the car, as well as how to set up the pulleys and belt, whether you have a USDM or JDM motor.

Pulleys and Belt

   I went with the K Power Idler/Tensioner Delete Kit. This completely simplifies your belt system, making it only the crank pulley, water pump, alternator, and the pulley from K Power. This is perfect if you're not running A/C and P/S. On the RX-8, the power steering pump is completely useless anyways, as it has an electric steering rack. I have never had a setup without a tensioner before, however I am very pleased with the amount of tension this setup provides. It feels like the perfect amount and the belt is very tight.

    If you have a USDM Motor, you can buy this kit and hook everything up. However, if you have a JDM motor like I do, it's going to be a bit more of a headache to put this together. You need to get a USDM crank pulley, alternator, and water pump housing. 

    The water pump housing is the big metal piece that bolts to the block, and holds the water pump and the alternator. The USDM water pump housing is entirely different shaped, and the alternator bolts up completely differently as well. I went to a junkyard and pulled the water pump housing off of some Accord, and got it for about $40. When you replace it, there's an o-ring inside of it that you'll want to replace; its part number is 19322-PCX-003. The rest of the housing I just gasketed on with RTV.

    For the alternator, I got a remanufactured Denso unit off of rockauto for $100ish plus $80 core. 

    The crank pulley on the JDM motors are larger than the USDM ones, making it incompatible with the belt size that comes with the K Power kit. I picked up a new Denso one for around $50 on rockauto. You can also take this opportunity to replace your front seal and woodruff key while you're in here.

JDM crank pulley measures to 6.5"

USDM Denso pulley measures to 6.1"

    I didn't see any installation instructions on the K Power kit, but the washers they provided me didn't fit the bolt they supplied. I went without them. This is how the pieces should go:

    To install, I first put the belt onto the pulleys. Then, I was able to put the end of the bolt into the hole to get it started, then I used a hammer to persuade it in until it reached the threads. no pry bar necessary :)

Intake Manifold

    I went with an S2000 Intake manifold because of the price and availability. I've been eyeballing the Skunk2 Race Intake Manifold for sometime now, however it's always reliably out of stock during this time. The one I have is from the 2000-2005 S2000. Unfortunately, this doesn't directly bolt up, so the first step to making this work was to get the Intake Manifold Adapter from JSP. They have V1 and V2. One is for a K20, and one is for a K24. The K24 one doesn't have the water passage at the end of it, which means you will have to use a Thermostat Bypass Adapter, which is something like this. I used this to block off the coolant coming out of this port.
    Read the installation instructions from JSP carefully. When using the K24 setup without the coolant passage on the adapter, you do not need to drill into the head for anything. All you need to do is elongate one of the bolt holes on the intake manifold, which it goes over how to do. TEST FIT YOUR INTAKE MANIFOLD FIRST by putting every bolt through it to make sure it fits BEFORE putting it on your motor. I made the mistake of only testing it with a few bolts, and it turns out I needed to elongate the hole on the intake manifold more.

    Once the adapter fitment is squared away, you now have to cut the intake manifold. The instructions don't go over cutting the backside of the manifold, but on this application I had to because the thermostat bypass adapter was in the way. This is what you have to cut:

And this is the result:

Once done properly, everything will fit right up and you will have an S2000 intake manifold bolted onto your K24 :) I had to move the clutch line bracket in order to get this to fit up against the firewall, but other than that, it was fairly painless. The ABS even fits snuggly next to it :)

That's all for this post! Up next will be fuel and exhaust manifold. 


  1. Absolutely loving this, maybe i missed it but how are you mounting the rx8 throttle body to the manifold?

  2. how are you going to mount the throttle body to the manifold and what about the iac port on it?


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