Quote:
Originally Posted by RobertISaar
and here's where theory meets pavement: the backpressure will impede the flow of exhaust gasses out of the exhaust port, rather hot exhaust gasses at that, there's a reason EGR is taken from a much cooler place in the exhaust stream. i would predict a weaker, significantly hotter air mass without water/methanol injection.
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Not at these power/boost levels. and I was half joking about the EGR statement. Using a very small turbine and high boost levels can cause a condition called "reversion" where the high back pressure from the small turbo can backflow exhaust gas during valve overlap. This is very bad and can result in severe detonation/engine damage. This usually happens when for example a kid with his stock small t25 equipped eclipse turbo puts a boost controller on and puts it through the roof with 30 psi. doesnt last long,ask me how I know. Btw, EGR gas on most gas engines is taken from one of the hottest part of the engines, the exhaust port or manifold.
But I'm not trying to start any arguments here, we don't have millions of dollars of test equipment like the big guys so no one's theories are hitting any pavement until we just try it. I'm hoping to gain some insight from the great minds on this site and share my results so it can be duplicated if successful.
One thing I was hoping to figure out and is usually the hardest part is the turbo sizing. I think I have a plan. T25 is on a stock dsm and runs 11ish psi boost with fast spool on a 2 liter. These are practically thrown away by the dsm guys due to being to small to make big hp numbers. Cheap on ebay all day, flanges and downpipes too. I might be able to squeeze one on the front bank of the van, if not I'll midship mount it underneath(connected to only one exhaust bank). Hook it up, set it at 5 psi and see what happens, if I don't like the results or not enough boost, add another.