If you rebuild or trade European passenger-car turbos, you have almost certainly quoted a "GT1749V" that turned out to be a GT1749VB — or the other way around. The two share the same frame size, the same footprint and, at a glance, the same castings. They are not interchangeable: fit the wrong one and the ECU's boost model no longer matches the hardware, giving overboost / underboost fault codes and limp mode.
What the model names actually mean
Garrett's naming packs real information. "GT17" is the frame size family, "49" is the trim indicator, and "V" stands for VNT — a variable nozzle ring turbo rather than a conventional wastegated unit. The trailing "B" marks a revised variant: updated compressor wheel and nozzle-ring geometry with a recalibrated actuator, matched to later engine management systems. Same family, different hardware.
The three differences that matter
| Feature | GT1749V | GT1749VB |
|---|---|---|
| Compressor wheel | Original BCI-geometry wheel | Revised wheel with different blade count/trim |
| VNT nozzle ring | First-generation ring geometry | Updated ring matched to the B-wheel flow |
| Actuator calibration | Earlier spring/rod setup | Recalibrated for later ECU boost maps |
In practice the fastest visual check is the compressor wheel and the nozzle ring — blade count and shape differ — followed by the actuator part number. But visual checks are only confirmation; the nameplate is the evidence.
How to identify yours in one minute
- Read the nameplate on the compressor housing — the turbo manufacturer number (for the V, commonly referenced under the 717478-xxx series) and often the vehicle OE number are stamped there.
- If the plate is unreadable, photograph the compressor wheel, the nozzle ring and the actuator.
- Send us the number or photos — we cross-reference against Garrett and OE numbering systems and confirm the correct unit before you order.
Ordering the right replacement
Both variants are available through our Europe turbo line as complete units, and we also supply the VNT service parts behind them — nozzle rings, actuators and rebuild kits — for shops that repair in-house.
Not sure which one you have? Send the OE number or photos — we confirm fitment within 24 hours, and every order is checked against the OE number before it ships.
FAQ
No. Same frame size, different compressor wheel, nozzle ring and actuator calibration. Wrong-fitment swaps trigger boost fault codes and limp mode.
A revised variant of the GT1749V platform — updated wheel and ring geometry, recalibrated actuator for later engine management.
Read the nameplate on the compressor housing. If it's unreadable, send us photos of the wheel, ring and actuator — we'll cross-reference them for free.