Introduction
The Nissan R33 GTR is an iconic performance car cherished by car enthusiasts worldwide, especially in the USA. A critical factor for maintaining its high performance is choosing the right transmission oil. One of the most common debates among R33 GTR owners is whether to use MT90 or 85W90NS for the gearbox.
MT90 offers better performance for the R33 GTR’s gearbox, while 85W90NS is ideal for heavy-duty, high-load conditions. Choose based on driving style and vehicle needs.
This article provides a detailed comparison of both oils, helping you make an informed decision that ensures your R33 GTR runs smoothly.
What is the R33 GTR?
The Nissan R33 GTR, produced between 1995 and 1998, is part of the famous Skyline GT-R lineage. Known for its advanced technology, including the ATTESA E-TS all-wheel-drive system and RB26DETT engine, the R33 GTR is a favorite for tuning and performance upgrades. To maintain such a car in peak condition, using the correct transmission oil is crucial.
Understanding Gear Oil Basics
Before diving into the debate of MT90 vs 85W90NS, let’s first understand the role of gear oil:
- Gear Oil Function: Gear oil is used to lubricate the gears and reduce friction between metal components.
- Viscosity Ratings: Oils like MT90 and 85W90NS are rated based on their viscosity. The higher the number, the thicker the oil, which affects its flow and performance.
- Additives: Gear oils often contain special additives that enhance lubrication, reduce wear, and protect against corrosion.
What is MT90?
MT90 is a synthetic 75W90 GL-4 gear oil developed by Red Line specifically for manual transmissions and transaxles. It’s designed to provide excellent wear protection, smoother shifting, and thermal stability under high performance.
Key Features of MT90:
- Smoother Shifts: MT90 helps reduce gear crunch, especially in cold weather.
- Thermal Stability: Ideal for high-temperature conditions, preventing oil breakdown.
- Low Sulfur: The lower sulfur content is less harsh on soft metals like brass synchronizers, common in the R33 GTR’s transmission.
Who Should Choose MT90?
- If you use your R33 GTR for daily driving or spirited street driving, MT90 is a great choice. Its smoother shifts and high-temperature stability make it ideal for city and highway use.
What is 85W90NS?
85W90NS is another gear oil from Red Line, but it’s a GL-5 rated oil, designed for hypoid differentials and heavy-duty applications. However, it’s formulated without friction modifiers, which makes it a potential candidate for use in synchronized transmissions like the R33 GTR.
Key Features of 85W90NS:
- High Load Capacity: Best for heavy-duty conditions and high-torque applications.
- No Friction Modifiers: Helps prevent slipperiness, improving performance in certain gearboxes.
- Thicker Viscosity: Provides superior protection under extreme loads and high temperatures.
Who Should Choose 85W90NS?
- If you track your R33 GTR or engage in heavy-duty racing or towing, 85W90NS may provide better protection for your transmission due to its thicker viscosity and load-bearing capacity.
MT90 vs 85W90NS: Which is Better for Your R33 GTR?
Both MT90 and 85W90NS have unique advantages, but the choice depends on how you drive your R33 GTR. Let’s break down the comparison:
| Feature | MT90 | 85W90NS |
|---|---|---|
| Viscosity | 75W90 | 85W90 |
| GL Rating | GL-4 (suitable for manual transmissions) | GL-5 (more suitable for differentials) |
| Temperature Stability | High, good for hot climates and high performance | Excellent for extreme loads |
| Shifting Smoothness | Excellent, reduces gear crunch | Moderate |
| Best For | Daily driving, spirited driving | Track use, heavy loads |
| Compatibility with R33 GTR | Highly recommended for smoother shifts | Suitable for heavy-duty applications |
Installation Tips and Best Practices
- Drain the Old Oil: Make sure to drain the old transmission fluid completely before adding new oil. You don’t want any mixing of old, possibly contaminated oil with your fresh gear oil.
- Check for Leaks: Inspect seals and gaskets before and after changing the oil to ensure no leaks. Leaking gear oil can cause significant damage to your transmission.
- Use Proper Tools: Always use a proper torque wrench to tighten drain plugs to the manufacturer’s recommended specification.
- Break-in Period: After replacing your gear oil, drive your R33 GTR gently for the first few hundred miles to allow the new oil to properly lubricate all components.
Expert Opinions
Some R33 GTR owners and mechanics swear by MT90, especially for daily driving and light track use. They praise its ability to offer smooth gear shifts, even in colder temperatures. On the other hand, 85W90NS gets recommendations for those who push their cars to the extreme on the track or use their GTR for heavy-duty applications like racing.
Performance Drivers:
- “I prefer MT90 for everyday driving. The shifts are smoother, and it performs well in both hot and cold weather.”
- “If you’re taking your GTR to the track regularly, 85W90NS can handle the extra stress better than MT90.”
Related Products
- Red Line MT90: Available in quarts, it’s recommended for most R33 GTR manual transmissions.
- Red Line 85W90NS: Ideal for those looking for a thicker, GL-5 rated gear oil for extreme conditions.
Both oils are widely available at most automotive retailers and online stores, including Amazon and eBay.
FAQs
1. Can I use 85W90NS in my R33 GTR transmission?
Yes, but 85W90NS is more suitable for extreme loads or track use. MT90 is better for daily driving.
2. How often should I change my transmission oil?
It’s recommended to change the transmission oil every 30,000 to 60,000 miles, depending on usage and driving conditions.
3. Does MT90 work in cold weather?
Yes, MT90 is known for providing smoother shifts, even in colder climates.
4. What’s the difference between GL-4 and GL-5 gear oils?
GL-4 oils are designed for synchronized transmissions, while GL-5 oils are typically used for differentials and offer better protection under heavy loads.
Conclusion
In the debate between MT90 and 85W90NS for the R33 GTR, both oils have their place. If you’re using your R33 GTR for regular driving or spirited street driving, MT90 is likely your best option due to its smoother shifts and better compatibility with the transmission. On the other hand, if you’re hitting the track often or pushing your GTR to its limits, 85W90NS might offer the extra protection you need. Ultimately, your driving style and how you use your car should dictate your choice.