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After receiving a huge number of requests, Polar Engineering brings a compact balance tube and IACV distribution block that is designed to work with AshSpec intake manifold for Z32 300ZX.


This is a bolt-on setup for all existing manifolds and will most likely be available as an add-on with all manifolds going forward. An assembly comes with everything you will need to bolt it up to your intake manifold, including a brand new, application specific formed silicone hose to connect IACV distribution block to driver side (USDM) charge pipe. The distribution block has an integrated OEM Mitsubishi BISS screw that is used for setting base idle. It is possible to purchase this assembly with an optional OEM Ford IACV and I strongly recommend taking that option with your order.



  • CAD designed to be a direct bolt on and work seamlessly with AshSpec intake manifold.
  • Distribution block and mounting adapter are CNC machined out of 6061 aluminum alloy and anodized for flawless finish with superior corrosion resistance.
  • The driver (USDM) side distribution block is the heart of this system. It acts as a manifold itself and joins, IACV, silicone hose and the balance tube. An OEM Mitsubishi BISS screw is integrated into the distribution block to allow for setting base idle and is a lot better accessible than factory Z32 counterpart. All parts of this assembly are joined using high temperature and chemical resistant orings for quick assembly/disassembly and a tight seal. All hardware in this setup is made of stainless steel.
  • The balance tube is made on a CNC press to generate exact replicas for large production runs. We were able to achieve an average deviation of only 0.3% in 25 tubes that were produced so far. A 25mm steel pipe was used for production to make sure that it allows adequate flow between end tanks of this volume and does not collapse under vacuum at high temperatures. Since this tube is pressfit and o-ring sealed, it can be swiveled up or down and then locked into position using a small set screw in the back of passenger side adapter. That allows it to clear all known fuel rail designs.
  • IACV distribution block connects to driver (USDM) side charge pipe using a custom made silicone hose that was produced specifically for this application. The hose contours driver end tank to keep all parts of this assembly compact and tucked as close to intake manifold as possible.
  • I am trying to keep color options as simple as possible for this assembly while still leaving some choices to the end user. The tube and silicone hose will only be available in black color. You will have default options of black or red for anodized finish of distribution blocks. If you would like a custom anodized color, it will also be available for additional $80.
  • It will be possible to order your setup with an OEM Ford IACV as a $65 option. I only use genuine Ford valves that have black composite body, premium valve materials and premium solenoids. I STONGLY encourage you to purchase your kit bundled up with IACV valve (which is available at a wholesale price). There are lots of counterfeit valves on the web. I only purchase these valves directly from a local Ford dealership to make sure all parts are authentic.



At this point, 25 metal tubes are already produced and 25 silicone hoses are in production to be finished in 10 days. Final machining order will be submitted by the end of next week. Realistically, I expect these to be delivered in the first week of August.


NOTE (and this is not some sort of a sales pitch):

I am only making 25 of these setups right now and that will likely be the only run this year since I am completely swamped with work on other projects. There are way more AshSpec manifolds in the wild that that, so if you want this setup, PLEASE ACT NOW. I will hate to disappoint you when you message me in a couple of months asking for these and they are all sold.



Balance tube assembly is priced at $300 (without IACV) in black or red color with $18 shipping in the 50 US states. CNC machining, production of custom press tooling and application specific hoses comes at a premium price. It is not possible to make cheap products without compromising quality and that is something that I do not do.



Flat rate $18 in continental USA (medium flat rate box rate).

International shipping is a flat rate $83 (current medium flat rate box rate).

All orders for South Pacific region need to be placed though Robert Sidaway at RGS Performance.

NISSAN Z32 300ZX Balance Tube System for AshSpec Intake Manifold

  • Once again, I strongly encourage you to order your setup bundled up with a genuine Ford idle air control valve. There are many aftermarket and counterfit productions out there that look similar, but simply do not perform the same way. This is a sure way to prevent any IACV related problems with setup, tuning and future operation. 

  • Many Polar Engineering parts, including all ignition system altering products, are sold for off-road use only. All performance modifications and installations are at the customers own risk.

    Polar Engineering or hold no responsibility either implied or otherwise for mechanical, electrical or other failure when using any aftermarket performance products. Items sold for off-road use only are illegal in many states and provinces and are intended for racing vehicles which may never be used on a public road.

    By purchasing any aftermarket performance product, the customer takes full responsibility for any use, and/or misuse of the product and agrees that Polar Engineering or holds no responsibility for any consequences, legal, or other, of such use and/or misuse.

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