At factory oil coolers featured a built-in thermostat bypass at the bottom of the oil cooler where the lines enter and exit the heat exchanger. The oil cooler is bypassed until the oil is up to operating temperature.
The Hayden Automotive “HD COOL” oil coolers are 37mm thick heavy-duty plate/fin heat exchangers that are ideal for transmission, engine, and differential oil cooling that require higher flow range and increased heat transfer capacity in a compact space. Their patented internal turbulation increases heat transfer and provides minimal pressure drop and use 37* JIC male flare (-12) fittings
Hayden has been around since 1961 when founder Perry Hayden invented the automotive transmission cooler after modifying a refrigerator condenser to extend the life of his tow vehicle’s transmission. Over the past 60 years, Hayden has become powertrain cooling experts serving OEM manufacturers with engine, transmission, and power steering coolers, as well as radiator fan clutches. Hayden holds multiple patents in how coolers operate that help maximize efficiency without sacrificing flow, along with many radiator clutch fan design patents.
COMPARING OIL COOLERS (AN EDUCATION)
When it comes to comparing oil coolers, it is virtually impossible to properly compare or judge them by their advertised BTU/HR rating. This is due to a lack of a standardized test procedure to determine the BUT/HR rating of a heat exchanger, and results in an extremely broad range that they are quoted at. When testing the efficiency of oil coolers, there are many variables in the test conditions that have a significant impact on the results, such as oil input temperatures, flow rate, pressure differentials, airflow temperature and speed, etc…
The 21-row Hayden (778) oil cooler measures at 8.78” x 12 15/16” x 1.75” and is advertised at 9,600-20,800 BTU/HR. – $105
The 19-row Setrab oil cooler (PN: 50-619-7612) measures at 5.75” x 13” x 1.83 and is advertised at 27,000-37,000 BTU/HR – $201
Going purely off of the advertised numbers, it would appear the Setrab would have 30-385% better cooling than the Hayden. However, actual back-to-back testing bench testing has shown virtually identical performance between the 2-row taller and slightly skinnier Hayden heat exchanger vs the Setrab across many different temperature and pressure conditions. Because of this, it is unfortunately pretty much impossible to compare one brand’s BTU/HR rating to another, but it is useful for seeing a relative % difference from one cooler size to another WITHIN THE SAME BRAND.
Due to Hayden’s decades of experience manufacturing these types of heat exchangers for OEMs, and due to their very affordable price points, the Hayden oil coolers are a no-brainer when it comes to cooling engine, transmissions, differentials, and power steering systems.
The 21-row Hayden Automotive “HD Cool” (778) oil cooler has a significantly larger surface area and over twice as many oil-carrying tubes than the factory 10-row Mazda cooler. We will be using two of these Hayden (778) heat exchangers to cool our FD.
The Hayden “HD Cool” 778 oil cooler is also notable thinner than the factory oil cooler.
We then mounted the oil cooler to the chassis with Radium Engineering -10ORB to -10AN Male Low Profile Swivel Fittings (PN: 20-1000-1010). These banjo fittings allowed for the oil cooler to be mounted as high as possible.
Quick Reference:
Page 1 – Stock FD RX-7 Oil Coolers
Page 2 – Hayden HD Cool 778 Oil Coolers
Page 3 – Oil Cooler Ducting
Page 4 – Improved Racing Remote Engine Oil Filter Mount & Thermostat
Page 5 – How to Make Earl’s Performance Stainless Steel Hose
Page 6 – Oil Plumbing Series vs Parallel & Radium Low Profile Swivel Fittings
Page 7 – Raceonly Billet Remote Oil Filter Pedestal & Front Iron Oiling
Page 8 – Raceonly Billet Oil Filler Neck & Improved Racing Catch Can
Page 9 – Crank Venting from Gutted OMP Port & Turbo Drain Fittings
Page 10 – Raceonly Billet Power Steering Reservoir
11 comments
I don’t think I could park this thing on the street knowing the man hours invested.
Good job. Helluva build.
This has been a great build to follow along. I noticed in the radiator articles you were calling it the BJR radiator. Are there plans for some of these parts to go into production?
I called it the Billy Johnson Racing (BJR) Radiator to give it a name because it was a custom build to my specifications for the FD platform. I’ve sold a few to people who reached out to HQ Engineering and ordered one, but this is a high-end motorsports radiator that’s priced in line with similar 50mm motorsports radiators (>$1,000) that should outperform anything on the market from my research based on its dimensions and efficiency (that fits within stock frame rails). The majority of FD owners are street guys who are use to $400-500 drop-in replacement radiators that are only slightly better than stock. If you need a significant improvement in cooling, you’ll have to spend more than double that wherever you go.
Thank you 🙂 It’s far from over…
Wow, beautifully done!
Out of curiosity why did you go with stainless braided lines over nylon braided? I’ve been choosing nylon braided lines since they’re lighter and easier to work with but I don’t have the experience with A/N lines you do.
I’m a big fan of nylon and use it in many applications, especially for those areas that will not see abrasion or impacts. We chose stainless because it was the only option at the time in the PTFE UltraPro -10AN hose, stainless is generally better protected for mission-critical fluids like oil lines that might see debris impacts, and because this new hose is so flexible and light, there really aren’t any downsides other than maybe a few ounces per foot. This -10AN is very light (37% lighter than traditional rubber w.stainless braid) and is extremely flexible with a 1.772″ minimum bend radius (vs 6.0″ minimum bend radius for the all-rubber Super Stock hose and 4.0″ for the rubber-lined stainless steel braided Auto-Flex hose). The UltraPro and new Ultra Flex 660 Stainless & 650 Kevlar Steel & Pro-Lite 390 Nylon hose are a significant improvement in quality than the impression that you or I might have on thinking of Earls as old-school, old-technology ‘hotrod’ hose vs many high-end motorsports hose brands. I’d bet that once you experience UltraPro & UltraFlex hose first hand, you’ll change your impression on Earl’s, like I did.
Thanks for the info Billy. I’m actually working on an oil cooler and catch can setup for Project EF Civic. I was going to use Earl’s nylon braided line but I will definitely take a look at the UltraFlex lines for the cooler itself. It’s a shame this sort of info isn’t easier to find on their website.
Happy to see that parallel flow oil cooler setup. A bit curious to hear that in prior history, others’ experience with the parallel vs series flow didn’t show dramatic differences in performance. I wonder if that was due to airflow restriction of the factory bumpers. Anyway, the reduction in pressure drop is worth the parallel setup alone. But I expect your setup to do well as you’ve properly accounted for the airflow.
Any particular reason you went with the Radium catch can over the Improved Racing one? Or just personal preference.
Love the update. Love all the blue anodized parts. Love the attention to detail.