leslie said:
wow, yet another thread which I fully cannot comprehend.
*feeling like a girlygirl*
Gato said he had the hook-up for a new cylinder head for the engine in his car. The cylinder head is the top part, where the valves (what lets in gas/air and lets out exhaust) and the spark plugs are. The camshafts are what open and close the valves, and the new cylinder head has two of them instead of just one. This means the engine can rev higher because each camshaft has less work to do. The new head has a lower compression ratio, which means the gas/air misture will be compressed a little less when the piston is at top dead center. But this won't be a problem because he wants to slap on a turbocharger (a piece where the exhaust gas flowing out of the engine drives some gears which in turn compress the air going into the engine). Gato then asked if this turbo would be likely to cause a lot of problems if it's set to boost the incoming air by 10 psi.
Kruz said he should be fine, but would be better off if he added an intercooler (a piece that cools down the compressed air to make the engine run more efficiently and control heat).
Gato then said he didn't really like the idea of adding an intercooler because he doesn't have a lot of spare room under the hood. He also said that he wants to get to around 300 horsepower for as little cost as he can, although the new head will cost him a pretty penny; but the camshafts are more agressive (they're set to open and close the valves at the right time for higher performance at the detriment of fuel economy and smooth idle). But his big worry about all this is that the engine, with the new head on it, will now be an interference-type (that means that if the timing belt, which turns the camshafts, breaks or something else breaks, the valves could remain open when they should be closed, and as the pistons continue to move up and down they would strike the valves, resulting in an amazing amount of damage to the engine). The people who have done projects similar to his (new head and a turbo) have said that if something goes wrong, the problems compound fast. But then again, these same people run a lot higher boost and are getting 425 horsepower out of their engines, while Gato is only looking to get about 300 horsepower out of it, meaning he would be stressing the engine less.
Kruz then posted an anecdote about his brother's Buick Grand National, which has some very agressive turbocharging. The gist of it is that he's got a trick setup to allow him to run that much boost while still being able to run gas you can buy at a regular gas station. The higher the octane rating, the more it can resist detonation ("pinging," when the gas ignites before the spark plug fires... which can really damage the engine too). Kruz's brother has to run supreme unleaded, but at least he doesn't have to use racing gas.
I was surprised because he said his brother buys 94 octane cas for it, and the highest octane rating I've seen out here is 92.
Then, you said you don't understand the thread.
Next, Gato said you can get 94-octane gas from 92-octane if you add in a bottle of Octane 104, which is an octane booster that you pour into the gas tank when you fill it up.
Finally, I summarized the thread.
Clear now?