Pros
Using the AccessPORT Stage 1 (97 RON) map, SP Engineering replaced the Sunoco 100-octane street fuel with VP Racing 109-octane fuel on our final run. The purpose of this test was to see if the higher octane fuel along with the Stage 1 97-octane map would make more power over the previous run. We knew the recalibrated Stage 1 map was not designed for 109-octane fuel and the possibility of a power loss was imminent, but we had to test this theory for ourselves. VP Racing Fuel 109 octane is the highest-octane unleaded fuel available on the market today. This high-octane fuel is recommended for higher boost applications with compression ratios up to 11:1, or naturally aspirated engines up to 13:1.
Cons
Similar to the cost of the 100 octane fuel, we found the VP 109 fuel to have a market price of 14-16 dollars per gallon. Unless your car is in dire need of this high-octane juice, we suggest proper tuning and conservative boost to minimize your chance of detonation.
Parts
VP fuels are available in 5- (19 liter), 15- (56 liter), 30- (113 liter) and 54-gallon (204 liter) pails and drums.
Tools
Fuel jug, funnel, misc. tools to drain 100-octane fuel
Installation Time
60 minutes
Notes
A spin on the dyno posted some interesting results as the GT-R lost power throughout the midrange. A common misconception among enthusiasts is the higher the octane, the more power your car will make. This theory would be plausible if the change in fuel was accompanied by proper tuning, but in our case, the vehicle had lost 12 to 16 hp and 18 to 22 lb-ft torque from 3,900 rpm to 5,000 rpm. It goes to show that one map calibration is not the final answer to all your fuel needs--don't blame the fuel or the AccessPORT; if both were mapped to work in harmony, we guarantee the R35 would have seen power increases over the 100-octane run.
| CONCLUSION |
| HP Level | +HP | TQ Level | +TQ |
| BASELINE | 449 | | 484 | |
| HKS EXHAUST | 464 | 35 | 497 | 33 |
| BASELINE | 449 | | 484 | |
| COBB TUNING ACCESSPORT | 474 | 25 | 498 | 14 |
| SUNOCO 100 OCTANE | 506 | 32 | 519 | 21 |
| VP RACING 109 OCTANE | 505 | -1 | 509 | -10 |
| FINAL | 505 | 56 | 509 | 25 |
Conclusion
Factoring in a loss of 1 hp and 10 lb-ft torque on our final dyno run, the GT-R still managed to post some impressive numbers using the Cobb AccessPORT and moderate octane increases. With a gain of 56 hp and 25 lb-ft torque over our baseline number, SP Engineering continues their research in finding ways to extract more horsepower from the GT-R. Look for our upcoming issue as we tackle the GT-R with the new HKS GT570 racing package.
| BANKROLL |
| COBB TUNING ACCESSPORT | $995.00 |
SUNOCO 100 OCTANE $10/GALLON X 18 GALLONS | $180.00 |
VP RACING FUEL 109 OCTANE $14/GALLON X 18 GALLONS | $252.00 |
| HKS EXHAUST | $3,200.00 |
| MSRP TOTAL | $4,627 |