BMR Reservoir Review and Comparison Thread

Full Disclosure: I purchased the BMR Reservoir at a slight discount ($25 off) with the intent of doing a review of the product and some IAT2 data.

Cliff Notes
Advantages:
* The tank is well made, quality workmanship and fits nicely in the typical location.
* Pre-drilled mounting holes are actually in the right location!
* Similar installation as NorCal tank, so if there are no instructions you can reference the sticky thread to figure it out
* Although slightly smaller than the NorCal tank, it is very large and appears to effectively double the coolant system volume, without creating fitment issues.
* Suggested Routing should provide the coolest temps to your intercooler (aka "Lid") when icing, such as at the drag strip.

Disadvantages:
* The screw-on lid requires their proprietary tool IMHO - I find myself checking coolant volume with the car running and the lid is HARD to get off with a warm engine bay. This is the biggest and most severe drawback - to me it reads like an excuse to charge an extra $25 for a special wrench; but honestly the BMR Reservoir is competitively priced even if you factor in the additional cost.
* Tank design may limit how some prefer to run their lines.
* Tank design may encourage internet nit-picking (ie "risk of cavitation") but I think this is highly unlikely
* Having a propriety tool to tighten the lid really is a pain in the ass. It should be included even if they have to raise the price $20.

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The box:






I had mine powder coated via Calico Coatings due to a shipping error, and they did a nice job. You can see the welded -AN male fittings (bottom is inlet, side is outlet), with the drain hose in NPT thread not yet installed (nor pictured). It's a quality piece and was well-packed for virtually no chance of damage. I purchased the -12 AN fittings direct from BMR and they are competitively priced.

The installation:

My instructions were either not included or misplaced by the coating company, however the installation is very similar to NorCal's posted instructions (CLICK HERE).

It is highly recommended that you remove the dual factory metal hard lines when installing the reservoir. You're going to do it, might as well do it now. You can get to most all the connections by removing the lower center splash tray from under the car to access the pump and heater Hx connections, and from the engine bay disconnect the battery post connection on the passenger side near the exhaust manifold - this allows you to gently feed the metal line assembly up and out (to be replaced by 3/4" rubber line):




You will need to trim several areas to get the box to fit properly, however it does fit very well with no rubbing against the cross member:



BMR suggests a specific routing to create the coldest fluid temps into the Lid when icing for the drag strip (likely the most common situation for CTSVOwners!); however some people such as road racers strongly prefer alternate arrangements for various purposes.

I used the BMR recommended routine in large part because it made it easier to join the heat exchanger to the Varimax pump. You will see in the following photos that it's a tight fit for hoses down there by the pump, so I reused the OEM hose vs risking a crimp in the softer 3/4" hose I bought locally. everything else has plenty of room no matter how you want to do it:

BMR recommended routing:



ETA: I finally settled on this routing*:


* Note: I routed my hoses through BMR tank "backwards," or inlet into the side and outlet to the bottom of the tank, so that the lower fitting drops straight down into my coolant pump for as little resistance to the pump as possible, or to "gravity feed" the pump. Doing this negates the ability to add ice as the coolant is not filtered for ice chunks in this manner. This is specific to the BMR tank design only. If you are going to ice, your "inlet" has to come in from the BOTTOM of the tank, and then flow out the SIDE of the tank so that ice chunks are filtered by the perforated tube.

My installation all finished up:
-removed incorrectly labeled photos-


Summary:
* I like everything about the BMR reservoir EXCEPT the need for their special "lid tool." it would be just as easy to machine a raised bar on the lid for hand-tightening rather than the recessed hard-on-the-fingers way they chose to.
* Some people feel there is a risk of cavitation or pulling air due to the "outlet" being slightly higher than the inlet. IMHO this is a non-issue on a properly topped-off system with minimal air trapped. The outlet is in the bottom 1/4th of the tank and I think it's highly unlikely for an air bubble to make it that far down as long as you are Shiny-Side-Up. If you run the tank less than 2/3 full (or have a leak), then I could see a risk of getting air trapped, but that's a maintenance issue. I personally think it's a non-issue.
* BMR's perforated tube design may potentially flow better than NorCal's mesh-screen design
* -12 AN fittings should equal the 3/4" NPT fittings on NorCal's tank; however material selection (such as brass) may significantly decrease the ID of NorCal's inlet/outlet, depending on what is provided.
* BMR is approximately 1.5 gallons vs NorCal's 1.7 gallons.
* IMHO any Reservoir/expansion tank will provide benefits, the specific tank you choose will be based on reputation, price, features and quality (likely in that order).

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So I looked at the data again to verify accuracy, mostly because some runs ended at 6200 RPM vs 6400 RPM, or had different ambient conditions, etc. So I've updated this post to show three separate, single-run comparisons of my original cooling setup vs the BMR reservoir only:




And the averaged results again:


* All runs were with a Varimax pump, ZL1 lid, and Track Attack; No tank vs the BMR Reservoir tank with 3/4" lines.
* MAX IAT2 was highest value recorded, typically 1-2 seconds after the run
* Additional data points for to illustrate recovery were added.
* Each set of runs (baseline vs BMR Reservoir) were matched to ambient conditions and starting IAT2, then averaged into the final comparison. I tried to make sure ambient conditions did not skew the comparisons either way, as I had 6-7 runs for each version.
* This was a reflection of my experience, your mileage may vary. Although I think we can safely say that the hotter it gets or the longer your pull is, the more benefit the reservoir becomes.