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

 

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.

 

Thanks Emilio, I appreciate the honest reply.

 

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?

 

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

 

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.

 

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.

 

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.

 

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.

 

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

robert

 

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.

 

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.

 

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.

 

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

 

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.

 

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.

 

TSE

 

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

 

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

 

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.