What about going for the BIG POWER? 300hp, 350hp or more? We would perhaps add the words, Reliable BIG POWER. For those of you who want to find out how much power a motor will take before it breaks, I salute you and your wallet. SPD Tuning Service only talks about making big power numbers with the expectation that the motor will live for a while and that it will be rebuilt as preventive maintenance, not because something broke. The Subaru WRX engine has been in development for 12 years at the factory and for 10 years at Prodrive alone. We know the limits, we know what internal modifications are needed and what fuel will make what kind of safe power. Why re-invent the wheel?

First you will have learned from the Stock Engine Mods section we do not like to quote raw power numbers, especially in road car applications. SPD Tuning Service runs flexible fuel engine management. We tune to very near the detonation threshold and rely on the engine management system to keep the engine off the ragged edge of self destruction. This way we are confident we are making as much safe power as possible. But, for the sake of this section, we will be throwing comparative horsepower numbers around. Please do not write back telling me that your motor makes 294.2 horse power and it has no problems running. That is entirely missing the point. We are saying that somewhere in the estimated 270-280hp range even a really well tuned pump-gas motor is going to hit the wall. If you feel that number is actually 295hp on your dyno, fuel and ambient conditions, we do not really care to have a argument, OK? 

We are not against running a turbo motor with the "big power". At the same time, we advise that going for THE BIG POWER may cause reliability issues and increase maintenance costs that can very quickly stretch one's ability to pay for the speed parts AND the maintenance. Some have the budget to go for broke, some of us may go broke trying! Here are several facts that one should consider when talking THE BIG POWER, especially if we cannot run a steady diet of high (98-100) octane fuel.

1) During the 2001 season the Prodrive Group N and Subaru Canada PGT cars were running very well sorted Group N engines on 100 octane gas. Restricted to 32mm the 300hp engines were still pulling some 370 ft-lbs torque. The stock WRX 5-speed gearbox was changed out for a fresh one every evening and/or 20 minute long service just to finish the rally. Running 32mm or 36mm intake restrictors and stock turbochargers. Although they are hard pressed to make 300hp, these cars have tremendous, 'cannon shot' torque output. The car needs a stronger gear box to run reliability for any significant mileage above 300 hp or more important above about 300 ft pounds torque.  Careful, clean shifting is demanded at any rate. I would say smooth shifting with a high power engine is true even if a stronger dog-clutch gear set or the expensive STI 6-speed are installed. The point to take is that, even if we get the engine running the "Big Power", we create maintenance issues in the drive train when running hard. Drag racers at 400+hp not only rebuild engines often, the shell out big money for drive axles and gearbox rebuilding, sometimes more than one set to get to the finals.

2) 91/94 octane gas has a practical limit of roughly 120-140 hp per liter before the fuel mixture must be set rich and the timing set several degrees later than is optimum for efficient combustion. 94 octane may easily run 145hp/liter for sure and it is fun. However, many 'expert' tuners are not afraid to run rich mixtures and late timing to get a bigger engine output, especially using normal 91/92 octane fuels. They do not have good control of the timing or boost curves, so they just throw a lot of fuel at it and call it tuned. The temptation is great. However these 'fat' running engines can expect more rapid engine wear and they are never going to run as crisp and clean as a properly tuned engine. 

3) There is a real potential for internal engine damage if running kits that promise more than about 280hp on pump gas. Or, as I have personally noted, some 300hp motors break ring lands and/or stick pistons. The ones that stay together do so by virtue of being rather optimistic about their true horsepower output numbers. The ultra high power engines survive by short bursts at high power levels and constantly face the danger of breaking a cast pistons. An SCCA autocross driver with a 17 psi boost kit from someone else ran 18,000 miles on 96 octane and promptly cracked a piston when it was fed 91 octane one weekend. Note, he was being cautious and ran high octane gas. Since they were not familiar with the risks and symptoms, the engine was run until it was completely trashed. I know of several owners who ran the same kit on 91 octane gas and did not last the month on the street before a piston let go. Why is this so?

So, yes, it is possible to 'flash' a pump gas running turbo motor for about 20 seconds to higher power levels, say 300hp and run sub 13 second quarter mile time. After this short time at full power,  heat starts to cause the combustion process to go sour. Detonation occurs and ka-pow! To keep the motor alive beyond a short time limit of say a minute of wide open throttle, one has to set the fuel mixture fat (rich fuel mixture) and use a setting with retarded timing. The pump gas feed engine will feel great for a while with the rich fuel cooling the cylinder and the late timing preventing detonation, but the piston/ring wear is enormous and the engine can quickly wear itself out. Perhaps in 30-40,000 miles of hard use it will begin to smoke badly and be down on power as the ring seal is lost.  On the other hand, it can still also stick a piston, crack a ring land or burn a valve. I have personally seen several cases of these types of failures.

In my experience there are the tuners who deliver a good 250/260hp modification, or some will tell you it is making 270hp. But, the numbers game aside, the point is they are smooth and run well making noticeably more power than stock. Then, I have seen engines actually making 300+hp, lots of power. It scares me to think what is going on in these engines and I have heard later that a couple of them have since broken.  In riding with their owners, they tend to make short runs through second gear and third gear and then return to normal driving. These cars are never seen at track days just flogging their engine for twenty to 30 minutes at a time. I could blow one of those engines up in 10 minutes of hard running.  Knowing it is dangerous, we prefer not taking our customers into this territory on a daily driver for obvious ($$$) reasons. Why have a $400 a month car payment, put $3500 in goodies on the credit card and then blow the motor? Now we have no way to get work and face an additional  $3500 repair bill. This is not a service we provide. Ask around, this tale has been told more than once. Let us agree that stock engine internals on pump gas do not SAFELY make the BIG POWER for very long.

So here we are. We are willing to run 98-100 gas, and we want to build an engine that is going to run a 200-300 hundred full power hours, about the normal life of a rally car engine at 350hp. As we go above this number, engine life goes down and preparation costs go up. It is estimated the EJ207 engine has a long term power limit of about 400hp. Move to 450hp and you measure engine life can begin measuring engine life in minutes. Yes, drag racers will get much more, but they will have an engine in the car, one in a bag and one on the bench. They measure engine life in seconds. All you have to do is ask yourself how you want to measure your engine life.

For a little over two years now SPD Tuning has been involved with developing and building EJ207 engines at 360hp. These are capable of running wide open for many hours. We are quite comfortable making the BIG POWER with the proper internals and fuel. But, for a street car, it is not reasonable to even discuss these engines because of the costs involved and the strict high octane fuel requirements. If you drive a rally car, then we are interested in working with your EJ207 and gearbox, as we are equally dedicated to making good solid road power from pump gas engines.