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BMR Reservoir Review and Comparison Thread

52K views 119 replies 40 participants last post by  STE\/E 
#1 · (Edited)
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.
 
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17
#4 ·
Honestly unless you're boiling coolant, this will be a relatively low pressure system. I personally ran the factory fill cap (5psi relief) for a margin of safety, however I suspect it's really not necessary unless you're going to see 200+ degree intercooler temps! Basically, I don't know enough about the system to tell you one way or another, but "anecdotal" experience here on the board suggests that you can run a closed system without ill effect. The factory filler T is relatively narrow.

Question: Are the -an fittings of choice (I see they offer -10, -12, -14) welded directly to the box?
Yes, the male -AN sized fitting is welded straight to the box, but you have to buy the proper female fittings of course.
 
#5 ·
Very nice write up. I'm sure this will help tons of people including myself. Looks like you ordered with 12an bungs. Does the 3/4 inch hose fit the stock HX fine? Just curious if I can run 3/4 lines with stock pump and HX.
 
#6 ·
Well detailed, in for your results. Might change my routing to this as well, but we have already talked this into submission in the other thread.

Looking forward to concrete data, the numbers don't lie. Well unless you want them to ... lol
 
#7 · (Edited)
:D I will admit that the single greatest modifier in causing me to adopt the BMR routing system was the confined space between the Pump and the Heat Exchanger - the formed OEM hose fits so nicely in that space compared the alternative routing options that I just went with it.

On the off chance I do decide to "ice" at the drag strip some day, I'll be ready to go!

Very nice write up. I'm sure this will help tons of people including myself. Looks like you ordered with 12an bungs. Does the 3/4 inch hose fit the stock HX fine? Just curious if I can run 3/4 lines with stock pump and HX.

The factory filler / T-fitting, metal lines and intercooler lid are all 5/8" if I understand correctly. I am using a Varimax pump, ZL1 lid with modified fittings and the Track Attack aftermarket heat exchanger (which all utilize 3/4" line well), so I can't say for sure.

I think it's worth pulling out the metal lines even in stock form as they are a restriction (narrow, 4-5 unnecessary bends).
 
#9 ·
Hmmm... first "after" run only showed a few degrees of lower IAT2 - not the slam dunk I was expecting.

Will get a few more runs in to average out the data....

Sent from my SCH-I545 using Tapatalk
 
#10 ·
Random,I am also going to be installing a BMR tank/Zl1 Lid combo.. Would a 10ft braided hose be the correct size to go with for the BMR tank ? I know you didn't go braided but figured you would know the length.
 
#15 · (Edited)
Hmmm... are you bypassing the metal lines going straight to the pump and hear Ex?

I'd say 4 ft from pump to tank, 4 ft from tank to lid, and 5-6 feet + a 90 degree end from the lid to the heat exchanger - this way you can avoid extra connections.

14 feet total and you should have a little left over; with braided I'd hate for you to come up short. ETA I verified that these lengths are correct, for how I routed things.

Sent from my SCH-I545 using Tapatalk
 
#12 ·
Is the drilled tube welded to the tank on both ends?
 
#18 ·
On stock setup I made it work with about 6ft. Think I bought like 8 and had some left over.
 
#19 ·
Just FYI, I've never needed the tool to take my lid off (when I had the box), you can use your fingers just as easily. It was actually my idea to come up with the handle to allow for me not to have to touch the lid when it's hot when putting ice in at the track.
 
#20 ·
That is BMR's position as well: "you don't need it."

However, as someone who just installed it, has tried to install and remove the lid multiple times while on the car topping off the system over the past few days... I will disagree. IMHO it's a limiting design relative to a typical user, and limits how firmly I can snug up the lid (and still get it off later).
 
#21 · (Edited)
Updated OP with IAT2 data (single runs, but otherwise as close to identical as it's going to get).
 
#23 ·
Are you going to log a run with the tank fully iced?
 
#26 · (Edited)
I bought mine before the -12an was available so im going to have to use an adapter to go up to -12an into my ZL1 lid. Same basic thing with my HX. Are these going to cause much issue in my cooling or are they small enough bottle necks that my flow will still be more than sufficient?
 
#50 ·
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#29 · (Edited)
Let me load up that GoFundMe link... :D

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ETA: The distilled water and water wetter is a real possibility, but I'd have to drain everything again which is a bit of a pain. I'm running out of time between now and the supercharger/phenolic spacers swap.
 
#31 ·
The DI water and correct amount of WW can net some pretty good changes. I saw 12° on my last vehicle going from factory coolant to a 85/15 water/WW mix
 
#33 ·
Let's just say that, for a daily driver, I have to plan on the occasional -10* F start up in January and February. The drain option is nice, but I left it off for now as I didn't plan on draining/filling again before the winter. Right now, when I use the mix testers I get 4/5 floating balls, which should be around 50-50. I verified both mixtures before the swap and kept the ratio the same.... for science!
 
#36 ·
So the extra capacity from the tank vs. the stock unit really isn't doing much in the chart?

I'm sure having the ZL1 lid, better pump, and heat exchanger helps tremendously already......
 
#38 ·
I don't want to repeat myself more than I already have, but you're seeing 4+ degrees temp difference with a 50-50 mix after less than SIX SECONDS of WOT run; and the delta is starting to look parabolic. I was limited to a single 3rd gear pull due to my circumstances, the repeatablility of the test and doing all of this on... well, not on a closed course.

If I was doing a quarter, half-mile, or multiple-gear highway run you're talking a double-digit differential in around 10 seconds, which is going to cost you 20 RWHP (or more) from pulled timing alone due to heat soak by the time you get into another gear. I don't think the benefits of a reservoir are in question here. I really don't even think the type of reservoir is so much an issue.

the only real question is "how much greater would the differential be over a completely stock system be (or how much WORSE would my IAT2's be if I didn't have the ZL1 lid, T/A and Varimax)?"

I don't know of anyone who's added 150+ RWHP to these cars and left the intercooler system stock, because the heat management is such an issue in summer temps. Maybe another way of looking at this is: even with an otherwise "full bolt-on" cooling system, the additional capacity from a reservoir seems to make a measurable difference in delaying IAT2 rise.
 
#37 ·
We designed the lid with the intentions of looks first. The lid handle does function well, but we didn't want a bulky handle sticking up. Many people have asked if we could weld the handle to the lid for them, the handle does not clear the hood with it attached the box so that is not an option. Also, keep in mind, this system is not pressurized so the lid does not need to be extremely tight.

As far as worrying about "Cavitation" goes, if the box is full there is obviously no problem. If it is low and you are racing while under throttle the fluid will be transferred to the back of the box where the suction line is anyway. I can see braking be a bit of a concern I suppose if road racing. BUT.....moral of the story is: Don't run your car low on fluid and you won't have problems.
 
#40 ·
Well... I seem to have more free time during "work" now that AshleyMadison is down?
 
#42 ·
I used a little synthetic grease on the o-ring just to ensure a snug fit and to reduce the likelihood of tearing the o-ring. I haven't noticed any leaks yet - but I assume the smell of dexcool is just residual from the installation! :D

Did you keep the OEM filler T for pressure relief?

ETA: I'd check to make sure the o-ring is in place, not torn and that there's no burr or machine marks where the o-ring sits just to be on the safe side. IMHO the design looks pretty straight forward so unless there's a defect somewhere, it shouldn't leak at the lid at all.
 
#44 ·
You know, to be fair I don't think the filler neck is required because let's face it, we're not boiling the coolant so pressurization / expansion should be a non-issue - but I kept mine plummed in-line if only as a visual reference for fluid level where I don't have to take the lid off to check.

As I edited in my above post, check the gasket for tears, the lid and reservoir mating surface for burrs or machining marks. Wipe it down and monitor over a few days to see if it's a constant leak or just residual from a messy install?
 
#45 ·
Cleaned a few times, lubed o ring, tightened well. I did have to burp my heat exchanger a couple times. I thought that might be the issue. I thought maybe it was boiling somewhere in the system causing it to be pressurized. I got out today and opened the hood and seemed like the tank was pressurized. (Lid looked pushed up)
 
#46 ·
This may seem like a silly question, I have a completely stock intercooler system besides a lid spacer. The car has made 570hp, gone 10.96 , sitting in the staging lanes with i/c pump and fans running iat2 was 106 after burn out and staging to launch iat2 was 115 and top of the run was 138. Timing is pulled at 140. Lets say I was to pick up this ice box and ice it down before a pass, is there really any gain to be had? Let say it dropped iat2 down significantly for the pass, would power increase due to the fact of "cooler" denser air? or is the main thing here that iat2s arent getting so hot that the pcm starts pulling timing?
 
#47 ·
Do you recall ambient air temps? I'd say the cooler inlet charge certainly could be improved - cooler is always better - but I'd also say getting definitive gains in your situation may be a longshot.

It's right up there with trunion upgrades, premium oils and everything else: some people get by just fine with Mobil 1 and factory rocker arms... others like additional insurance.

If you're positive that the scenario you described is your worst-case scenario for heat and IAT2, then I'd say your combo is pretty balanced and you can save the $300 for gas! But knowing how these cars handle heat... I'm wary of that truly being the case. All I can do is share my experiences in an open, and hopefully unbiased manner - whether or not it's "worth it" is up to the individual and the circumstance.

If I lived on the Northern Coast where temps stay cooler, I might have much less vested interest in additional cooling capacity. Down south, you take every little bit you can get (and run 100% distilled water with some Water wetter year-round!).
 
#51 · (Edited)
No, it means that heat transfer takes some amount of time to transfer from air or aluminum into water, and then from water back into aluminum then ambient air. What you are talking about is much like turning on the grill, knowing that the gas flame will burn you but the lid at the top of the grill is still relatively cool:

The heat energy has already been produced, it just hasn't been picked up by the IAT2 sensor yet.
 
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