This page was written in response to the frequently asked question: the difference between the Surbo and the turbo.
2. Both increase the acceleration power of the vehicle, the turbo with increasing boost, while the Surbo provides a flat boost profile, somewhat like a high lift cam, and is more controllable over bends.
3. Both take a moment before full super charging takes place. For the Surbo, there is an "activation sequence" (How Surbo Works), while the turbo needs a certain engine rpm and throttle opening before the exhaust has enough air speed to drive the turbo (phenomenon known as turbo lag).
The good news is, they can work together, as the Surbo can cut the turbo lag (the Surbo's increased low rpm airflow speeds up the exhaust gases, which turn the turbocharger on boost earlier).
2. The Surbo gives improvement even from idle. For example, for automatic vehicles, the Surbo provides instant takeoff with no delay due to very low end improvement (shown by increased rpm at idle, or extra hill holding ability). For turbos, since there is some lag, the starting off may not be as quick compared to its non-turbo version of similar horsepower.
3. Location: the Surbo is placed along the air intake. It could be at the inlet to the air filter case, its outlet, or pipe after the filter case towards the throttle. The turbo is always located at the exhaust manifold of the engine.
4. Legality: the Surbo is compliant with requirements of LTA Singapore as it is fitted before the intake manifold and does not cause added emission, while installation of a turbo for a non-turbo vehicle is not allowed because it is considered an exhaust modification.
5. The Surbo extends the rev capability of an engine, typically sending it to its rpm red line with part throttle, and its power does not drop sharply from that point (see Dynamometer Test Results). In fact it is possible to extend the rpm by just taking out the rev limit, and we have done twin cammed-engined cars that could achieve 90 to above 100 kph in first gear (the list includes Toyota Vios, Proton Gen 2, Honda Civic VTi, and Accord Euro R). A turbocharged engine has a narrower power band, because once the engine torque dips and exhaust gases slow, the turbocharger slows, and there will be a sharp rolloff in power.
6. Fuel consumption is lower in a Surbo-equipped vehicle, but may not be lower in a turbocharged vehicle, reason being that before the turbo is on, the engine has less power due to inherent lower compression, built-in to cater for extra compression when the turbocharger delivers full boost. A 1.6 turbocharged engine, when on boost, has not only the power output of a 2.4 normally aspirated vehicle, but also its consumption. However, on a Surbo vehicle, since the Surbo is fully on only during acceleration, it avoids the full time large capacity fuel consumption.
7. The Surbo requires minimal diy or installer maintenance of the sealed air intake system, while the turbo system and pipes require workshop maintenance, and sometimes expensive guesswork in finding the fault. The Surbo lasts a lifetime, but not a turbo.
8. The Surbo does not heat up the air going through it, but a turbo system does as it is driven by hot exhaust gases, so much that an intercooler is required. For long drives, a turbo car may need breaks to cool off, but not a Surbo car, as it runs cooler because of less fuel input (less combustion heat) due to a lighter throttle. On a trip to Penang from Johor Bahru, a Surbo-equipped Peugeot 207 GTi arrived an hour before a standard Subaru WRX STi, for the above reason, and had better fuel economy, requiring fewer stops for petrol. Both cars were turbocharged.
9. The Surbo depends on an airtight installation to provide an intake manifold back pressure to activate its compressive air jets, while the turbo depends on sufficient flow of exhaust gases to turn itself, which the Surbo can provide from a lower rpm.
10. The Surbo brings earlier, higher compression while avoiding overly high compression (and heat) from flooring the accelerator (as it takes the engine to its rpm red line with part throttle, so not needing to use full compression). On our test Peugeot 508 1.6 turbo, the Surbo pushed the engine to its rev limit with just 1/2 throttle and only 0.6 bar. On a comparable turbocharged car of around the same horsepower, the turbo pushes the engine with very highly compressed air at around 1 bar so the engine parts will fail sooner. Or if the Surbo-equipped engine is taken to the same 1 bar, the revs will go higher, if the rev cut is removed. There is just more headroom on a Surbo-powered vehicle. More potential.
11. Blow-off valve. A turbo system requires a blow-off valve to limit pressure. When the pressure limit is reached, and blow off occurs, the pressure in the turbo drops, so loss of power occurs, as time is required for charging up again. A Surbo-equipped engine may not require a blow-off valve. As observed on a turbocharged Subaru Legacy 2.5 GT fitted with a Surbo, blow-off did not occur anymore, because at part-throttle, the engine would already reach the rpm limit.
12. For turbo diesel automatics (Chevrolet Epica LT), the accelerator has to be floored to call the turbo fully (which can bring higher diesel consumption and even smoke), but not for a similar Surbo-equipped vehicle, which requires only part throttle for the turbocharging to act.
13. The Surbo adds almost no weight or bulk, but a turbo system does, being so much more complicated and voluminous.
14. A Surbo-fitted vehicle costs nothing more to insure, but a vehicle known to have a turbo will be more costly to insure.
15. Tuning a turbocharged car by remapping or chips usually involve running the car at a higher turbo boost, which will shorten the life of the engine. By adding a Surbo, the excessively high turbo pressures can be avoided by part throttling, giving a higher safety factor. We had even fitted the Surbo on the VW Golf 1.4 GT of one senior tuner in Singapore, who charged $1800 per remap. It was something he could clearly feel, he said. We also did quite a few remapped turbo cars, mostly Jettas. In general, the more torquey your car, the better the Surbo acts.
The Surbo costs very much less than a turbo system, and the fuel saving will pay for itself. Even if your vehicle is already turbocharged, it's still great fun to spool the turbo earlier with a Surbo. So call us today to put a Surbo to enhance your vehicle.
Related pages:
Watch the video above showing how an engine revs with Surbo. Or watch it with the How it works page.
Above: video of Volvo XC90 T8 with Surbo, sprinting to 130 kph.
Above: video of Volvo XC90 T8 with Surbo, sprinting to 211 kph.
Above: video of Volvo XC90 T8 with Surbo, sprinting to 224 kph.
More torque and BHP (dyno test)
Quick revving (1/2 throttle to RPM limit)
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