timk

The previous owner of my car fitted an ASI (Chinese) 52mm radiator, I'm looking to swap to the VH060650 for a more efficient core.

Anyone have any real world track experience with these new 2015 Koyo Hyper V-Core radiators?

Cheers

emilio700

iTrader: (3)

We have a few street, HPDE and race cars running these. No controlled A/B testing but it *appears* they are nearly as efficient as our crossflows. Running hard (track) for 25 minutes in hot weather the temps drift only a little. Old Koyo would climb 10-20°. Crossflow climbs 0-5°. Hyper-V seems to be 5-10°. That again, is uncontrolled data and likely to be a little inaccurate. Many variables too. That's without a vented hood. Add a well vented hood and all those temps drop. Even the old Koyo could be made to control a 250whp HPDE car with every other cooling trick employed.

So overall, and sort of generically, I put the Hyper V halfway between the old 37mm Koyo and a good Crossflow.

timk

Thanks Emilio, I appreciate the honest reply.

Joe Perez

iTrader: (8)

Smartass content:

I support any Miata cooling product which has the word "Hyper" in its name.



Serious content:

Not knowing what a "Hyper V-Core" radiator was, I googled it and landed on Koyo's "Radiator Technology" page. There I found a description of their "N-FLO Technology" (multi-pass radiator.) To wit:
Allowing coolant to remain in the radiator for a longer period of time?

Last time I checked, the amount of time coolant remained in the radiator was governed by only two factors:

• The flowrate of the water (liters per minute), and
• The size (volume) of the radiator.

Now, having worked in the corporate equipment-manufacturing world myself, I understand that there is a large disconnect between Engineering and Marketing. But still...


Am I missing something?

adamiata

iTrader: (1)

No. The water will travel farther though the radiator at a higher speed.

Joe Perez

iTrader: (8)

The water will travel through the radiator at exactly the same speed, assuming you define velocity through the radiator as the average time elapsed between a single water molecule entering the top and that same molecule exiting out the bottom.



Now, I'll be the first to admit that I don't understand the justification for running a multi-pass radiator over a conventional one. Both have the same active area and the same volume, and should perform equally. Yet some people staunchly support the idea that multi-pass radiators offer a performance advantage, at least in some conditions.

Is there a solid technical justification for this, or are multi-pass radiators a gris-gris? I have no idea.

adamiata

iTrader: (1)

But that water molecule has to take a longer path between the inlet and outlet. So a higher linear speed within the core tubes.

But you're right, the literature is wrong.

emilio700

iTrader: (3)

Hyper-V not to be confused with N-Flo, multi pass or whatever it is. Hyper-V is simply more FPI, (Fins Per Inch). Rest of the radiator is the same as the old V&R series rads. For most motorsports oriented radiators in production based cars (given pressure gradients, temp deltas), 18-21 FPI is sort of the sweet spot in fin density. The previous Koyos were about 14FPI. With the Hyper-V Koyo enters the modern era where all purpose built, higher end radiators are using 18-21 FPI.

Our crossflow, TSE, FM, PWR, Ron Davis, C&R are all in the 18-21FPI range.

Leafy

iTrader: (1)

The higher linear speed is the good part here. Makes for a higher reynolds number. Forced convection is not time dependent. I think I'd rather see the triple pass setup go back to front rather than side to side though.

robertcope

Does this mean that you won't be making more Crossflows? Should I auction my NOS Crossflow off?

robert

humming

iTrader: (2)

This made me happy.

FWIW I have the old Koyo 37mm, and have a really hard time with temps just driving on the freeway here in phoenix. If it's 100°F or higher, I'm gonna see 220 if I have the AC and I'm not really comfortable with that. My hood vent helps, but it's not enough area by itself. I I'm not keen to cut more holes though, because I park my car outside. I logged it coming home from work for a week before the vent, and then again after and I think it’s given a 2-3° improvement. The biggest help I saw so far was from sealing the OEM fan shroud to the radiator using aluminum tape. That was good for about 5° by my observation. If I could do it again I would have bought the 53mm koyo.

Joe Perez

iTrader: (8)

Understood, wasn't confusing the two. Merely noting that while researching the Hyper-V, I came across the aforementioned apparent misinformation on the Multipass.

(And I got a pretty good chuckle out of the GIF.)




I can see that. Higher velocity = more turbulent flow inside the core.

I'd love to see some hard data that compares the heat transfer potential of two otherwise identical radiators back to back.

emilio700

iTrader: (3)

Crossflow is still go. Just no ETA. Had to fire the original engineer. Good work but seriously overbooked himself. It's all in house now and moving forward.

scenturion

iTrader: (9)

Wow, are that many design changes needed? I should upgrade from my v1 to v2 when it comes out

emilio700

iTrader: (3)

Just fitment stuff. Same basic unit and performance, you would be hard pressed to tell them apart. Final rev will just fit better and be easier to install.

TheBandit

iTrader: (8)

I'm now at the crossroads of needing a radiator and as the 949 is on the undefined hiatus I'm looking at this Hyper V Koyo unit and FM's version of the crossflow. My wallet wants the Koyo, but I don't want another situation where $100-200 would have saved me downtime and irritation.

nitrodann

TSE

timk

I haven't had a chance to install this yet but there's not many pics out there showing the Hyper V core, so here we go:





Hopefully this thing works better than my old radiator!

Cheers

emilio700

iTrader: (3)

Our revised Crossflow was put back into production a few weeks ago but is still probably 10 weeks away. Long lead time. Revisions are to make it fit better and allow NB's to retain A/C. Not taking pre orders until they are in port. Website will have a "buy" button when we do so.

Meanwhile, here is a pic I took of the NA Hyper-V

WMP

iTrader: (1)

Sorry to resurrect an old thread, but I have this radiator on my NB. Last night I noticed it has what appears to be a bung for a temperature sending unit right next to the water inlet. Is this a good place to get a reasonably accurate reading? Obviously, closer to the engine would be better, but I haven't done a reroute yet and I don't want to screw anything up.

If so, does anyone know what size/thread dimension it is? I want to replace my factory temp gauge with something that's accurate and has numbers, and this seems like an easy way to do it.

** Never mind. I think it's 1/8NPT since apparently that's what they put on all their other radiators. It'll work for now.