The NISMO Sports Titanium Muffler 20100-RSR51 is essentially a factory-engineered lightweight exhaust upgrade for the R35 GT-R, designed around the VR38DETT rather than simply being a loud aftermarket exhaust.
NISMO’s official specification identifies it for 2007–2015 Japanese-domestic R35 GT-Rs, excluding the 2-seat models.
1. The engineering idea
Think of the exhaust as a trade-off between:
Gas flow → mass → acoustic control → thermal behavior → chassis balance
NISMO attacks this primarily through high-purity titanium alloy.
The complete system consists of:
Center pipe → rear muffler → tail sections
with the tail sections riveted together.
The important part is that NISMO isn’t simply making the pipes enormous.
- Main pipe: φ70 mm
- Tail pipe: φ60 mm
- Finisher: φ120 mm
- System weight: 9.4 kg
- Claimed reduction vs. OEM: 8.0 kg
2. Why 8 kg matters on an R35
This is where the product becomes more interesting than its headline “titanium exhaust” suggests.
Removing approximately 8 kg from the rear of the car means:
Lower vehicle mass + less rear overhang mass + lower rotational/inertial penalty
The R35 is already a sophisticated AWD performance car. Consequently, reducing unnecessary exhaust mass can contribute to a slightly more responsive overall vehicle.
But don’t interpret this as:
“8 kg lighter = huge horsepower gain.”
It isn’t.
The major benefit is mass reduction and response, rather than a dramatic engine-power increase.
NISMO itself reports the product as 9.4 kg versus approximately 17.4 kg for the measured OEM system.
3. Why titanium?
Titanium is extremely attractive for performance exhaust engineering because it offers a combination of:
high strength + relatively low density + high-temperature capability.
For the same structural requirement, titanium can allow the exhaust designer to remove substantial mass compared with conventional steel construction.
And there is another interesting characteristic:
Titanium changes colour with heat.
That characteristic isn’t necessarily damage. NISMO specifically states that colour changes can occur during use and that the degree/location depends on operating conditions; this does not affect performance.
So the golden/blue/purple heat coloration is effectively part of the visual character of a titanium exhaust.
4. The sound philosophy is VERY NISMO
This is probably the biggest misconception.
You might expect:
Titanium = extremely loud
But NISMO deliberately went in another direction.
Its philosophy is approximately:
Low rpm → restrained
Mid rpm → progressively sharper
High rpm → lightweight, crisp titanium character
NISMO specifically states that the R35 system was developed to be quieter than the standard exhaust during practical operating ranges, while producing the characteristic light exhaust tone of titanium at mid-to-high rpm. It also paid particular attention to reducing cabin resonance at low rpm.
That’s a very different philosophy from an exhaust designed primarily for maximum volume.
5. Noise numbers
NISMO lists different measured proximity-noise values depending on R35 model year:
|
R35 model |
Noise |
|
2007 - 2010 (to Mar. 2010) |
89.1 dB |
|
2010 (Apr. onward) |
90 dB |
|
2011 |
91 dB |
|
2012 - 2015 |
93 dB |
This is why you shouldn’t describe the 20100-RSR51 simply as a “loud exhaust.”
It’s better described as:
OEM+ motorsport-derived exhaust character with substantially reduced mass.
6. The hidden advantage: NVH engineering
This is where NISMO’s engineering philosophy becomes apparent.
NVH =
Noise + Vibration + Harshness
Many aggressive exhaust systems create:
low-rpm resonance → cabin drone → unpleasant cruising
NISMO specifically tried to suppress this phenomenon.
So the target isn’t:
LOUD ALL THE TIME
but rather:
civilized cruising → increasingly expressive acceleration → crisp high-rpm character.
That’s a much more sophisticated calibration.
7. Does it increase VR38 power?
Don’t expect a huge horsepower jump.
The exhaust can reduce restriction relative to the factory system, but the principal engineering objective of this particular component is weight reduction + exhaust character, rather than becoming a maximum-flow race exhaust.
Think of the hierarchy:
Titanium construction
↓
8 kg mass reduction
↓
lower system inertia
↓
different exhaust acoustics
↓
potentially improved exhaust flow
↓
small supporting contribution to engine performance
rather than:
Titanium → enormous horsepower increase
That’s an important distinction.
8. Why the φ70 mm main pipe is interesting
A common aftermarket philosophy is:
“Bigger pipe = more power.”
That’s incomplete.
Exhaust engineering is about balancing:
cross-sectional area + gas velocity + pressure drop + pulse interaction + turbine behavior + acoustic requirements.
The VR38 is a 3.8-litre twin-turbo V6, so exhaust gas management is particularly important.
Oversizing an exhaust doesn’t automatically maximize performance.
NISMO’s relatively conservative 70 mm main diameter demonstrates that the system was designed around a complete vehicle/engine package rather than simply chasing the largest possible tube diameter.
9. Where it sits in the R35 modification hierarchy
I’d classify it like this:
|
Category |
20100-RSR51 |
|
Weight reduction |
⭐️⭐️⭐️⭐️⭐️ |
|
OEM integration |
⭐️⭐️⭐️⭐️⭐️ |
|
Sound quality |
⭐️⭐️⭐️⭐️⭐️ |
|
Maximum loudness |
⭐️⭐️ |
|
Maximum-flow racing focus |
⭐️⭐️⭐️ |
|
Street refinement |
⭐️⭐️⭐️⭐️⭐️ |
|
Titanium construction |
⭐️⭐️⭐️⭐️⭐️ |
|
Motorsport/NISMO pedigree |
⭐️⭐️⭐️⭐️⭐️ |
The key word is balance.
10. The really clever part
The R35 GT-R is already an extremely engineered platform.
Therefore, a good modification isn’t necessarily the one that produces the most dramatic dyno number.
A sophisticated modification improves several parameters simultaneously:
−8 kg mass
- ●
titanium construction
- ●
controlled acoustics
- ●
factory-like fitment
- ●
no change in minimum ground clearance
- ●
NISMO engineering calibration
That’s why this exhaust is more interesting than a generic “performance muffler.”
NISMO also states that the product received prior certification under Japan’s replacement-muffler certification system for applicable vehicles produced from April 2010 onward.
Conclusion
Think of 20100-RSR51 as the “OEM+ surgical exhaust” for the R35.
It doesn’t try to transform the GT-R into an obnoxiously loud race car.
Instead:
OEM exhaust
→ heavy
→ conservative sound
→ large mass
NISMO Titanium
→ 9.4 kg
→ −8 kg
→ restrained low-rpm behavior
→ sharper mid/high-rpm titanium character
→ NISMO-developed acoustic control
So its greatest performance characteristic isn’t actually sound.
It’s mass efficiency.
For an R35, that’s a very intelligent upgrade because you’re removing roughly 8 kg from the rear of the car while simultaneously changing the acoustic character, without turning the car into a permanently loud machine.
