Okay I just replaced my stock radiator with a new Koyo N Flow and I have been reading some articles where it says that for the N Flow to work the right way, (proper cooling) the stock water pump needs to be replaced with a higher flow output rated pump.
Any advise ?

 

First, what articles are you reading? Legitimate publications, referenced by the manufacturer, or some blog about some dude's build that is nothing like yours? What does Koyo say? I would only trust the manufacturer's installation/maintenance publications. Now, depending on your mods, there's a whole lot of variables that no one here would be able to answer without knowing some high amount of detail.

 

My car is a 94 stock with upgraded AST, cheap bastard stock intake and JDM downpipe all done for reliability.
This is one of the threads I found talking about cooling and water pump issues when replacing with N-Flo dual pass :

https://www.rx7club.com/3rd-generati...estion-894363/

 

Back in the early days of the FD, most front mount ICs blocked the complete front inlet to the radiator.
They mounted directly against the plastic inlet which is very small.
That reduced air flow to the A/C condenser and radiator.

Blitz then came out with a recessed FMIC which fixed that problem. That is what I have.
Removing the inlet corner plastic pieces and installing aluminum blocking plates to cover the side and bottom openings where air escaped improved air flow through the radiator.
Inserting a nose ex pander helps also.

Next came the "V" mounts which were mainly for racing which further helped with air flow. But they are worse if you need the A/C.
Then the 99+ nose came out which further helped.

The stock water pump is fine if you use an under-drive to it to prevent over revving.
Or get the ?? pump with the better impeller blades.

 

Have you every really looked at the stock cooling system around the radiator and fans?
Both the air filter box and battery box make it hard for good air flow through the radiator.
They restrict the air flow and cause it to bend about 45 degrees down.
Even the stock IC will backflow into the air intake in first gear at full throttle.
They did not fix that until about 1999.

Either move the battery to one of the cargo bins behind the seats or replace it with a smaller battery about 1/2 to 1/3 the size.
This requires you to cap off the cooling duct to the battery box.
The out of production M2 (Mostly Mazda) cold air induction filter system helped fix the problem with the stock air filter box.

 

Thanks for responses!
I have decided to remove the N Flo and put back the OEM radiator since my temps are running 10 degrees hotter with the N Flo. I believe it is because of the OEM has a lot more cooling fin density. I know the weak spot is suppose to be the plastic end caps but the radiator is only about 5 years old so it has alot of life left.

 

 

While filling up the Koyo N Pass, did you loosen the center section air bleed bolt to remove air from that section?

 

See picture.

 

 

I replaced my stock radiator with a 3 pass Koyo about 7 years ago and have had no ill effects, either in summertime California traffic or at the track. No other water cooling upgrades at all besides a little splash or Water Wetter.(70% distilled water, 30% coolant and a shotglass or two of water wetter).
I do have stock dual oil coolers, a downpipe, and a bigger smic. If you also have those 4 cooling mods and are still running hot...How's that ducting look? Is the stock front skidplate in good condition?

For me, proper ducting went a long way.

 

What dose the water wetter do ?

 

You did not answer my question about bleeding the radiator with the black plug on top of the radiator, the one shown in the picture I posted.

 

Water Wetter reduces water surface tension thus enabling the water to make better contact with the metal surfaces.

 

Here are some details from RedLine (the maker of water wetter)'s site:

• Product Details

 

 

Straight from the Koyo website, they have been including this notice in the box with the radiator also.
Koyorad Racing - Frequently Asked Questions (FAQ)
What type of fluid, coolant or antifreeze does Koyorad recommend?

High quality antifreeze and coolant protects your engine by lowering water’s freezing point and raising water’s boiling point. Antifreeze and coolant provides anti-corrosion properties for the metals in your radiator and cooling passages within your vehicles engine. It also provides proper lubrication for the water pump. Dex-Cool is not to be used with Koyorad All-Aluminum radiators.

It is important that the proper coolant is used for your Koyorad All Aluminum Racing Radiator. Koyorad All-Aluminum Radiators must NOT be used with coolant additives such as "Ice", "Boost", "Wetter" types. Conventional "Green" type Ethylene Glycol based 50/50 premix is the only recommended coolant and mix which should be used. Dex-Cool is not to be used with Koyorad All-Aluminum radiators. Failing to use the proper coolant type and mix will immediately void any warranty. Using additives with water only (distilled or tap) with or without coolant can quickly corrode and destroy aluminum in a cooling system (including a radiator).
When a new Koyorad radiator is installed, we recommend a complete cooling system flush and fill with new coolant. If Dex-Cool was used in the cooling systme previously, a thorough cooling system flush is necessary. Neglecting a full cooling system flush or using the wrong coolant may result in corrosion, tube blockage, leaks, and premature wear and tear, not to mention other stresses on your engines cooling system.

 

In my racecar with aluminum radiators, I've been using Valvoline Super Coolant - link: https://www.valvoline.com/our-produc...olant-additive .

Valvoline info page: https://na21.springcm.com/atlas/Link...2-ac162d889bd1

It's also shown on the Summit Racing site: https://www.summitracing.com/parts/vpv-856054

It's the best coolant additive I've ever used - absolutely no corrosion, better cooling than green antifreeze, etc. And it's inexpensive and approved for on-track use at racing events.

 

I guess me and pretty much everyone I know is getting lucky with our Koyos at the track, because I've seen no problems at all with water wetter. Been using it since like 2001 in all my cars, equipped with Koyos, Fluidynes and stock Mazda radiators.

It's in my FD right now. No orange coolant ever, but water wetter, yes. I'll bet that disclaimer was written by a lawyer, and not a mechanic or water-wetter-on-aluminum expert.

 

so....1 full bottle into my current system ? What is this orange coolant you speak of ? Thanks in advance

 

I believe the ratio is something like 5 cap-fulls per liter. I just pour some in and try to round down. Definitely not a whole bottle in one shot though.

Dexcool is the orange stuff. I heard it's evil and eats gaskets. I don't remember where I heard (or read) this, but it kind of stuck with me. I'm sure there's been a discussion or two about it here on the 7 club.

hah sorry for the vagueness.

 

Yes I did bleed radiator through the plug on top of radiator when intial filling prior to engine start. Then I installed the inter cooler and air box, started engine filled leslie funnel keeping it with a level of coolant and watching air bubbles, unhooked TB hose until coolant escaped air free.

 

Certainly not written by someone familiar with actual racing or off-road usage practices.

 

thanks , i put in about 2oz. 2 shot glass

what is the Down side of putting too much ?

 

For Info:
I did remove the Koyo N Flo and put back the OEM radiator and guess what my coolant Temps went back to 8 or 10 degrees cooler !!!!
Confused but feel better with the OEM installed.