| Deciding on the boost level attainable has a lot of | | | | the limiting factors from above. |
| different factors. One would be octane of the fuel. | | | | The size of the turbo, or more the efficiency of the |
| Another is static compression ratio. Combustion | | | | turbo in your boost level also has a large factor in |
| chamber design also plays a big role in this. Also the | | | | this. The less efficient the turbo is at the boost level |
| size of turbo, and maximum engine power before | | | | you are at, the more heat energy is needed to run in |
| failure has a role in all this also. | | | | and put in to your engine because of it. Most stock |
| Some engines can handle a lot, such as the 2jz, in | | | | turbos are usually too small for the application in the |
| stock block form has been known to handle close to | | | | first place. They are made for response and have no |
| 1000hp and over at times with some reliability. The | | | | real consideration of what the car actually needs to |
| RB26 has a reputation for being able to handle these | | | | run properly. Some are undersized because of |
| power levels, but in no where near stock form. The | | | | limitations placed on the designers by car makers. |
| 2jz is a beast, it is built like a desiel truck engine. It | | | | Whether it is a number not to go over, or a number |
| has huge bearings, big bolts, a lot of meat throughout | | | | to stay away from so it doesn't get in the way of |
| the whole block. | | | | the more expensive cars, they are always told to |
| The type of fuel is the first limiting factor in the | | | | stay in check. |
| amount of air you can push. It is directly related to | | | | Limits of the engine is by far the least of most |
| compression also. They go hand in hand. An easy | | | | peoples concern. I have seen a few blow over the |
| way to tell if your pushing it too far, is when you | | | | years because of this, but this is the exception not |
| have to start to drop timing instead of holding static | | | | the rule. I would venture to say over 90% of engine |
| or increasing timing, while power is also increasing. If | | | | failures in turbo cars are from knock damage. |
| you find mbt at 1 bar increase boost to 1.2bar and all | | | | Whether it is a broke piston, or melted cylinder this |
| the sudden need to decrease timing by 6 degrees, | | | | by far is the most common. Which brings us back to |
| you have met the limit of your fuel/compression | | | | the first part of this. You must be careful with the |
| combo. If you can increase boost leaving timing the | | | | static compression/ fuel settings. One bad thing is |
| same or within say 2 degrees of same with no hint | | | | that it will be a different number for every engine |
| of knock, you can turn it up, until you reach one of | | | | type. Which makes my job all the more interesting. |