Steve Dallas

As mentioned earlier in this thread, a CAI is nothing more than a noise maker in this car. You can expect roughly zero net power gain from one. If you must do it, AEM and Racing Beat are the only two CAIs that will not cost you power and cause rough idle issues.

The Koyo V Series radiator is a good unit. CSF also makes a good one for the RX-8. These are the only two radiators that we recommend. All others have fitment and/or performance issues.

gwilliams6

I have the Mazdaspeed/AEM CAI on my RX8, and Steve Dallas is correct, that and Racing Beat CAI are the only ones that won't actually rob you of performance. Expect maybe a few hp improvement, ambient intake temp depending. . Sounds like your car came with the CAI already installed, correct ? What brand is yours ?

The Koyo has no fitment issues, likewise the CSF. The CSF is another quality unit, but at a premium price vs the Koyo. Either one is an excellent choice.

Steve Dallas

Also, since you are building a "drift rocket," don't overlook the fans. You will need a pair of high performance SPAL fans in a custom shroud to keep the car cool. You can try a FAL 490 shroud at 3,000 CFM, but I'm not sure it will be enough for drifting. A pair of SPALs at 3740 CFM is a better bet.

LittleAngleFromHell

Thanks Steve Dallas, i was really wondering if the fan needed to be change since im upgrading my radiator ! You just anwsered my question much appreciated

NotAPreppie

The is actually $30 cheaper than the comparable all-aluminum though both are about $100 more than the OE-style, plastic end-tank Koyo.

gwilliams6

You are correct about the price of CSF radiator. I was thinking about the Ron Davis custom racing radiator for the RX8. It costs over $600 and some racers swear by it. I have the Koyo V2695 in my RX8 and it is great for my needs. .

Ron Davis Competition Radiators - Mazda RX-8 - Off Line Racing

Steve Dallas

Depends on where you buy the Koyo. It pays to shop around.

V2695 - Koyo Radiator - V-Series - Race Consulting Agency - PARTS | KNOWLEDGE | PASSION


Even at the $30 price difference, it obviously makes sense to purchase the one that performs better. Trouble is, I don't think we know which one that is.

gwilliams6

Based on my feedback from other RX8 owners, and my own rotary wrench who has built and worked on stock, modified, road race and dragster rotaries for decades, their word is the Koyo V-rad is the first choice for price and performance in an easy upgrade. Not knocking the CSF or the Ron Davis for they have their fans also.

Steve Dallas

I think I wrote this up on another thread somewhere, but...

I have the Koyo HH Series radiator in my RX-8, and the Koyo Hyper V Series radiator in my Miata.

The HH radiator is fine. I write about it extensively in the Series 2 thread. It takes longer to saturate and recovers quickly, but it only holds peak temps down by a few degrees over the OE unit.

The Hyper V radiator is flippin' amazing in my Miata. It is a little known fact that NA and NB Miatas run HOT. Like 220F cruising down the highway with the A/C on in summertime. With the VS radiator, the car now runs the thermostat temp under the same conditions, and I have not seen peak water temp exceed 205F on the track yet.

In the Miata world, the current thinking is, the less expensive Koyo is the way to go, if you are staying normally aspirated. It will also work with low boost turbos and all supercharger applications. If you are turbocharged to over 200whp, the equivalent CSF is recommended, and 949 Racing's CSF crossflow is highly recommended. Hood vents are also recommended.

None of these comparisons are like-for-like, obviously, but that's all I have.

Since the OP is talking about drifting, he needs all the cooling he can get. That means the best radiator and best fans on the market. The Hyper V certainly doesn't suck, but I wonder if the Ron Davis is substantially better? If it is, that is what he needs.

TeamRX8

iTrader: (25)

S1 is the regular V series, not Hyper V. The thicker S2 HH model will bolt in on an S1, just that one fan shroud bolt hole won't line up and it can be left off. There are different Ron Davis versions. The usual suspect is the lesser version that's no different than the others; just a slightly thicker aluminum version that otherwise duplicates the OE radiator. The Ron Davis race 2-pass radiator was a whole different animal that makes the others look like toys, but it was kind of half bolt-in, half modify it to fit and there is some issue about whether they'll sell you one anymore. Only other similar 2-pass is from RX8Performance (see vendor area on this forum) and it has good reviews.

However, the one thing that has been overlooked the most is the fan/shroud issue. Bolting bigger fans/shroud on won't necessarily help when it's really needed since the fans usually don't run when that car is at speed. In that situation the OE fan/shroud assembly actually inhibits the true potential flow through the radiator, a lot more than people realize. That's about as misunderstood here as the idea of blocking in the radiator to try and force more air through it, which not only does the opposite by creating overheating in the engine bay but also reduces the ability to accelerate at high (racing) speeds

https://www.rx8club.com/rx8performan...tor-v2-259722/


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gwilliams6

The 2-pass Ron Davis may be best for the OP's drifting car. Checked with my rotary wrench, and he has installed it on a few race rotaries without too much trouble. It is being sold. I was actually close (one computer click away) from buying a Ron Davis 2-pass when I did my recent radiator upgrade, but for my driving needs the Koyo V was sufficient. For my needs I didn't need to spent $650 on a radiator. The OP may need to spend on the Ron Davis 2-pass or similar.

Steve Dallas

Obviously, I'm not a drifter and have limited knowledge in that area. My thinking is that drifting is a relatively low speed, high load affair, which seems to indicate high flow fans with effective shrouds should be employed. Certainly, the shrouds can be flapped to allow some flow during higher speeds to limit the amount of restriction. But yeah. There are several considerations when choosing a fan / shroud setup for any given application.

I keep forgetting that the Koyo S1 radiator is just a V and not a Hyper V. D'OH!

mrgnex

Just put one of those chinese vortex things in your intake!

NotAPreppie

Suich

Can you use any other air filters besides the one from AEM?

pintobronco

I have an AEM cold air system on my 2005 RX8 and wonder if the MAF sensor is the same as stock???
al

gwilliams6

Yes the same

jsanderbeck

Old thread but does anyone know of a Dry filter that can replace the K&N used in the Racing Beat REVI ?? Thanks

mazdaverx7

iTrader: (6)

Not off hand. You may want to bring it into a parts store and match it up with one in stock. You can measure the inside diameter of the mount as well as the outside mounting surface and as long as its very close in shape and filter size, it should work. That's where I would start.

You can always call Racing Beat and ask them what the filter number is and also see if that number can be cross referenced to a paper filter number. The only setback would be if the filter they use is either a custom filter for their application or a universal fit K&N.

Nadrealista

this

200.mph

iTrader: (9)

the split sch40 pvc pipe with dual filters is the best noob. i dont have the pics on this computer and am too lazy to find it

TeamRX8

iTrader: (25)

they’re still on the forum, 😂

that one above is kind of cool
​​​​​​.

TeamRX8

iTrader: (25)

They say it’s a custom K&N design, so maybe not. They never really show it fully taken apart and what the actual filter mounting end looks like. Some pics might help since I’ve never had my hands on one before, having always made my own instead, including ordering custom K&N filters which they offer as a side business.

There’s nothing wrong with it being a K&N. I know there’s a lot of the usual intrawebz rumbling over that, but if you honestly are concerned about it my suggestion would be to instead buy a filter sock to put over it, which would also prevent water ingestion if that were ever to occur. LMK if you need more info.
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UnknownJinX

Do you mean this thing?





That dual filter was quite the something.

Like good grief, what kind of contraption for air intake on this forum have we not seen? I feel like it's less of a race to gain power(more on that later) and more of a race to see who can come up with the most stupid-looking one.

Regarding the power gain from CAI on an RX-8, I would like to see if it's consistent. Usually, without a tune, the power gain likely won't stay after MAF figures out what you have done and adjust the fuel trim accordingly. Of course, there is always the eye candy/sound argument, which is fine, I was just never convinced enough to buy one while I had the 8. If it comes with a tune for MAF, retains the warranty(which most 8s are out of at this point), and can improve throttle response then that would have convinced me more.

Regarding ram intake... Usually, the gains can be realized only at high speeds, and even then, the static pressure change from the air at high speed isn't all that much. If you want more compression of intake air, well, you know what to get...

Nadrealista

Working on Cold air intake for $8 - 4” aluminum dryer hose with stock air box and filter :-) . Fits perfectly.