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Old 02-09-2018, 02:25 PM   #1
Scooby Specialist
Member Sales Rating: (51)
Member#: 138994
Join Date: Jan 2007
Chapter/Region: MWSOC
Location: DeKalb-ish, IL
06 WRX Ltd

Default Radium Engineering fuel rails

There were no useful reviews found when I was looking for fuel rails. Was considering Radium Engineering rails as a possibility which also had very little info out there. So here we go...
Specifically the fuel rails Radium markets as upgrade kits*.
20-0167-01 kit w/ AN fittings and plugs
20-0167-02 kit w/o AN fittings and plugs

spacer OD 19.1mm
spacer ID 9.6mm
short spacer height 14.5mm (+6.3mm stub into rail)
long spacer height 26.8mm (+6.3mm stub into rail)
short bolts M8x1.25 50mm length
long bolts M8x1.25 60mm length
phenolic washers 14.3mm OD / 8.4mm ID / 1.5mm thick

*Note on the conversion kits (20-0168-01 and 20-0168-02). They do a poop job of identifying that the rails are NOT the same in each kit. Main difference between upgrade and conversion rails is 11mm inj pockets -vs- 14mm inj pockets. 14mm inj pockets are machined into the conversion rails. Also the conversion kits come with extra parts and it is possible the "short" and "long" spacers could be a different length than the "short" and "long" spacers in the upgrade kits. This is why I hate when "short/long/etc" is used instead of actual dimensions.

Sourcing/Price: It is what it is.
Pro - These are a bit spendy compared to other brand fuel rails out there. It was Radium's features that interested me enough to invest a bit more.

Moot - Purchased these myself, I'm not sponsored. But if they wanted to send me a shirt or hat I would be pretty stoked. I really did not require aftermarket fuel rails for my setup. Adding them does offer up some flexibility for how I wanted to route my fuel system now and later on. These will add additional complication to get them integrated though.

Con - Appears that Radium has strong influence over the market pricing of their parts regardless of whom you buy them through. Unless you get free shipping with a distributor, I would recommend buying direct from Radium since their shipping costs are reasonable. Likely Radium's shipping cost is close to the same as part distributor will charge. I bought from a popular part distributor and they ended up drop-shipping from Radium . I would buy direct from Radium next time since that process annoys the hell out of me when not clearly indicated prior to purchase.

Packaging: I rate as acceptable with room for improvement.
Pro - These rails shipped in a plain box that does not clue the world into what might be inside. The hardware are all in nice part bags. There are some stickers included +5hp +5hp. **Another order tells differently though.

Con - Radium shrink wraps the rails touching together which is OK but might mar the finish during shipping. No instructions included (but they are on the website). Crumpled paper packing is OK but once it packs down the parts move around more. Just something to think about.

**Another order shipped in a plain box with colorful RADIUM logo'ed packing tape. So that positive is pretty much a con now. Some will say this is being too picky. Really why the hell do I want someone to know the package is from Radium (not cheap parts) so they can decide they need it more than I? Perform your marketing in other places that do not pose risk to your customer...duh.

Pro - The matte black anodized finish outer/inner is great. There are no machined logos, so no collecting dirt issues. All of the ports are -8ORB, including the Fuel Pulse Damper (FPD) port*. The inj pockets are through machined all the way to the rail gallery. Radium's earlier version rails were not through machined. Hardware is A2-70 stainless which is nice. Whomever makes their AN fittings does a good job, they appear to be good quality pieces. O-rings are all brown Viton.

Moot - I really was not overly concerned with heat transfer from the TGV housings. So the phenolic insulating spacers and washers were not really a motivating factor or detractor. They are nice components though.

Con - The laser etched logos are a bit much, I would prefer less is more. Inner bore machining will work fine but was clearly done with an inferior process compared to the rest of the rail machining. There was some minor machining flash/burrs where the inj pockets meet the rail gallery. Was able to clear those out but would like to see improved inspection for this. We all should be checking for stuff like this regardless...right?

*There are currently two fuel rails available with FPD ports. NPT threaded ports do not seal worth a poop compared to the -#ORB ports. This was a major factor that pushed these over my 2nd choice brand. If I was not at all interested in adding FPD's to the system then I would choose fuel rails completely void of these 3rd ports.

Installation: Keep in mind I am installing into a 2006 WRX with single AVCS, aftermarket TGV delete housings, ID1300x2 injectors (fitted a few types and OEM inj), and AN fuel lines in series.
Pro - They fit as do other aftermarket rails by bolting to the TGV housings. Radium's mounting design does allow for more ability to adjust mounting height than other brand fuel rails using machined-in brackets. So far they clear the AVCS, but they are very close.

Moot - No experience on how these fit on non-TGV type intake manifold arrangements (JDM, 25i, etc) but there are other threads that seem to cover some of those setups. Waiting on FPDs to come in so I can see how those integrate with these rails...will add when I can

Con - The injector pockets appear to be longer (reach lower towards TGV inj pockets) than OEM rails, which is not uncommon on aftermarket rails. However it does pose some issues with fitting some injectors. The phenolic insulating spacers are (by my experience with multiple injectors) no longer appropriate lengths. The instructions call out possible need for additional spacer washers with 0.17"-0.19" thickness. I had to fit and measure to determine the right amount of rail height I needed*.

*In my case I set my desired rail height based on where I wanted the top injector o-ring to sit inside the rail injector pocket and pocket clearance to the injector body. I needed 21.0mm spacer height. So this was 6.6mm more height than the short spacers or remove 5.7mm from the long spacers. I tried 3/4" OD / 3/8" ID / 1/4" thick alloy spacers under the short phenolic spacers to get the height I needed. his would need some M8x1.25 55mm length hex cap screws to cover the extra reach. This worked perfectly for FPD clearance to the TGV housings but it is so close to the AVCS plug that the harness connector barely-to not fits in place. If these were non-AVCS heads then I would have stuck with this setup. Instead I went back to using a 0.17"-0.19" washer under the short spacers.
Note: What I settled on here may or may not work for another setup. But it is a good reference point.

Pro - Radium responded to an emailed tech question the next day. I had heard some comment that their support can be spotty. So far this has not been my experience. Their response was a very brief but sufficient answer. I can see how some might interpret a short response as rude so maybe...

Moot - They have typically shipped quickly on my orders.

Con - None so far.

Still a bit of work in progress since I am not finished with complete project. I will update but decided to start the review thread to share what I have so far and maintain motivation to finish the review. Will add photos later and as I go...

If you could not tell already I will bluntly call it as it is. I could give two poops about pandering to a MFR, vendor, forum-popular idea, or the forum itself. Although so far my experiences with Radium and their parts has been very positive. I want useful information to select parts from instead of having to buy multiples, select based on assumptions, or having to modify parts that should work as-is dang it. So that is what I strive to provide.
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Last edited by JarHarms; 05-22-2018 at 11:47 PM.
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Old 02-09-2018, 02:26 PM   #2
Scooby Specialist
Member Sales Rating: (51)
Member#: 138994
Join Date: Jan 2007
Chapter/Region: MWSOC
Location: DeKalb-ish, IL
06 WRX Ltd


Initial mock install

With the 0.25" alloy spacers

Last edited by JarHarms; 05-22-2018 at 11:49 PM.
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Old 09-09-2019, 05:52 AM   #3
NASIOC Supporter
Member Sales Rating: (0)
Member#: 436019
Join Date: Dec 2015
Chapter/Region: RMIC
Location: Colorado Springs
2018 STi RA #406-500
Peral White

Default Same Setup

I actually have the exact same setup that I'm currently installing on my 2018 STI. I ended up cutting the long Fuel Rail spacers down slightly to get a better fitment with the injectors instead of using spacers. I did want to ask you how you went about connecting the FPD's I was thinking of using the factory FPR port on the ITMF for the FPD's since Radium ECT. recommend tapping the BOV hose for there FPR.

I would like to know how you finished your setup?





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Old 09-09-2019, 03:29 PM   #4
Scooby Specialist
Member Sales Rating: (51)
Member#: 138994
Join Date: Jan 2007
Chapter/Region: MWSOC
Location: DeKalb-ish, IL
06 WRX Ltd


I will also end up shortening the long spacers and ditch the extra spacers. Just waiting to prove out the system first.
I tee'd into the BPV hose close to the manifold port for my Radium regulator. I permanently plugged my RHS factory regulator port. I removed the harness bracket right by the throttle body. Then drilled the hole through, tapped 1/8npt, and added a tee fitting. Each tee side goes to the FPDs. Longer hose than I'd like but wanted plenum signal instead of runner signals. I have some other photos showing this on my build thread that might help.
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