ASpec CVT Transmission Fluid Options

[slowcountry]

Nerding out on CVT fluid over here... Was talking to AI about whether to stick with the Honda/Idemitsu HCF-2 CVT Transmission Fluid, or going to something like Ravenol or AMSOIL. Gemini thinks that using anything other than the Honda HCF-2 voids the transmission warranty, but we're already tuned and bolted on so I'm not too worried there.

Here's some data on the different fluids available:

Metric	Idemitsu H2 (OEM Baseline)	AMSOIL Synthetic CVT	Ravenol HCF-2	What This Metric Means
Base Oil Type	Synthetic Blend / Group III	100% Synthetic	100% Synthetic (PAO-based)	PAO (Group IV) is the most stable synthetic base, superior to Group III.
Viscosity @ 100°C	7.07 cSt	7.3 cSt	6.95 cSt	How thick the fluid is at operating temp (100°C = 212°F). All are very close, as required by the HCF-2 spec.
Viscosity @ 40°C	29.20 cSt	34.9 cSt	24.95 cSt	How thick the fluid is during a "cold" start. A lower number means less drag and smoother operation when cold.
Viscosity Index (VI)	Not Published	183	265	The single most important metric here. A higher VI means the fluid's viscosity changes less as it heats up. A VI of 265 is exceptionally high and indicates extreme stability.
Pour Point	Not Published	-46°C / -51°F	-54°C / -65°F	The lowest temperature at which the fluid will still pour. Ravenol has a significant advantage in extreme cold.
Flash Point	Not Published	218°C / 424°F	180°C / 356°F	The temperature at which the fluid's vapors can ignite. A higher number is better, indicating superior thermal stability and resistance to "boiling off" or breaking down under extreme heat.
Brookfield Viscosity @ -40°C	8,800 mPa·s	9,051 mPa·s	2,520 mPa·s	This is the actual measure of cold-start performance. The fluid must be pumped by the transmission, and Ravenol's number is drastically lower (better). It will flow and protect components far more easily in deep cold than any of the others.

Based on the data, here is the breakdown.

1. Idemitsu HCF-2 (The OEM Baseline)

This is the benchmark. It's a high-quality (likely Group III synthetic blend) fluid engineered to do its job perfectly well for the 60,000-mile life of the fluid in a stock car. Its specs are balanced and meet the HCF-2 requirement.

2. AMSOIL Synthetic CVT
AMSOIL's philosophy is Heat & Durability.

• Its biggest strength is the Flash Point. At 218°C, it is significantly more resistant to thermal breakdown than the Ravenol. This is a major consideration for a tuned, bolt-on car that is being driven hard, as you'll be generating far more heat in the CVT than a stock car.
• Its viscosity (VI of 183) is very stable, and its 40°C/100°C numbers are slightly thicker than the others, which can provide a thicker-feeling "cushion" of protection on the belt and pulleys at high temps.
• Its cold-start performance is effectively the same as the OEM fluid.

The AMSOIL advantage: Superior resistance to heat breakdown and varnish formation.

3. Ravenol HCF-2 Fluid
Ravenol's philosophy is Stability & Efficiency.

• Its base oil is superior. It's the only one that explicitly states it uses PAO (Group IV) base stocks. This is the foundation for all its other wins.
• Its Viscosity Index (265) is phenomenal. This is in a different league. It means the fluid's performance will be incredibly consistent, whether the transmission is at -20°F or 200°F. This consistency is ideal for a high-performance application where you want predictable behavior.
• Its cold-start performance is unmatched. The Brookfield Viscosity is ~70% lower (better) than its competitors. This means on a cold start, the fluid provides immediate lubrication, reducing wear and drag.

The Ravenol advantage: Unmatched fluid stability across the entire temperature range and superior base stock, which often translates to a longer-performing life.

• Choose AMSOIL if... Your primary concern is heat. If you plan on tracking the car, driving it extremely hard in hot Arkansas summers, or are just most worried about cooking the fluid, AMSOIL's high flash point provides the best protection against thermal breakdown.
• Choose Ravenol if... Your primary concern is ultimate stability and consistency. The PAO base and sky-high Viscosity Index mean this fluid will be the most "stable" and "like new" across the widest possible range of temperatures. It's an engineer's choice, focusing on the absolute best base-stock and viscosity performance.

Leaning towards Ravenol... Any opinions? Mostly curious if anyone has actually used the Ravenol or Amsoil fluids in place of the OEM. Or, is the consensus to stick with the OEM HCF-2?

I have a transmission fluid cooler to install, so planning to get some on hand here. Figured I'd flush the system while I'm at it.

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[Tony M.]

I’ve been using Korean Kixx CVTF fluid in my Honda Civic X, and I’ve driven over 20,000 km with no issues. . However, I was worried about potentially buying a counterfeit product — I live in Russia, and since the sanctions were introduced, many fake goods have appeared on the market. Additionally, the price of genuine Honda transmission fluid has risen to over $100 for a 4‑liter container.

Because of this, many Honda owners have started looking for alternative options. Among the trusted and reliable alternatives, multi‑vehicle fluids from Korean brands Kixx and ZIC have proven to be good choices.

In my view, the importance of the oil brand name is often overrated. The primary purpose of any transmission fluid is to lubricate all components and resist burning under high loads. What matters more than the brand is regular fluid changes.

So why experiment with alternatives when original products are available on store shelves at reasonable prices?

 

[Respectspirit]

2023 aspec tech. There is no question. There's only one answer. Amsoil. Dropped the OEM piss water at 500 miles did three consecutive drains of amsoil CVT fluid, I drive hard I change mine every year just to ease your mind your CVT has a cooler in place already. You're welcome 🫡

 

[slowcountry]

2023 aspec tech. There is no question. There's only one answer. Amsoil. Dropped the OEM piss water at 500 miles did three consecutive drains of amsoil CVT fluid, I drive hard I change mine every year just to ease your mind your CVT has a cooler in place already. You're welcome 🫡

Love it, haha. Are you in a hotter or colder area?

I'm just going for a little extra caution with the extra load - there's a pretty simple bolt on transmission fluid cooler from ETL that mounts behind the front bumper:

 

[tamilrmx_anu]

I use Amsoil CVT fluid in my 24 Integra Aspec. Changed it out 5 times, first time was at the 1,000km mark. I noticed better shifting, cold temp performance, and better mpg. I also use their oils, atf, gear oil in my other cars as well. Its really good product.

 

[Respectspirit]

Amen brother.

 

[Respectspirit]

Love it, haha. Are you in a hotter or colder area?

I'm just going for a little extra caution with the extra load - there's a pretty simple bolt on transmission fluid cooler from ETL that mounts behind the front bumper:

The cooler can only help it can't hurt. With the amsoil CVT fluid you'll at least have the peace of mind to know that you have full thermal protection no matter what happens.

 

[Respectspirit]

The cooler can only help it can't hurt. With the amsoil CVT fluid you'll at least have the peace of mind to know that you have full thermal protection no matter what happens.

I'm in SoCal by the way so warm temperatures, putting it down light to light.

Amsoil signature series 0W- 20, PLM charge pipe, PLM turbo inlet pipe, PLM billet intercooler, big three wire upgrade with ofc zero gauge wire, hyper ground kit 5 points, voltage stabilizer, turbo blanket, amsoil synthetic Dot 4 brake fluid with stainless steel brake lines, reverse radiator cooler hoses, front strut bar.
Old school.

Step by step, inch by inch.

 

[Respectspirit]

I'm in SoCal by the way so warm temperatures, putting it down light to light.

Amsoil signature series 0W- 20, PLM charge pipe, PLM turbo inlet pipe, PLM billet intercooler, big three wire upgrade with ofc zero gauge wire, hyper ground kit 5 points, voltage stabilizer, turbo blanket, amsoil synthetic Dot 4 brake fluid with stainless steel brake lines, reverse radiator cooler hoses, front strut bar. Dynamic friction advanced 5000 series brake pads front and back.
Old school.

Step by step, inch by inch.

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