Michigan Rotary Club
Technical and Performance => Engine Management Forum => : ~Groll69~ June 22, 2012, 10:03:44 AM
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As my baby comes together, we were talking about other fun applications to get a little more out of the NA engine. The idea came up to do nitrous on it. My questions is what is the best direction to go with the Nitrous mod? Should i do a wet shot or dry shot, oh big of a bottle should i have? Best most affordable kit to go with etc. Since i have never done nitrous on a vehicle before i am open to suggestions on the best route to take with this mod.
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wet is safest and more consistent from what I've been told.
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A 50hp wet shot will work perfectly. Buy it off of Craigslist. Retard timing 2 degrees. Profit!!!
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Will, are you going to try to start a new catch phrase with that? "Profit." Could work. Keep it going till it catches lol.
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Nope, just quoting southpark "stage 1: Underpants. stage 2:????? Stage 3: profit.
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You absolutely want to do a wet shot, since our motors are very sensitive to detonation - adding nitrous is analogous to forcing more air into the engine, and if you don't increase the fuel (wet shot), you'll end up with a high-load lean condition, which is what pops turbo motors all the time. Especially with a stock ECU, the ECU won't detect that its too lean & correct enough for it until you're already detonating, causing damage over time if not immediately
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That is true, the computer system and sensors associated with it are slightly primative in the fact that they can not adjust the air fuel ratio fast enough to accomadte the increase or decrease in the air flow.
That would explain why at low compression I flood out with the current stock injector setup. If the computer was able to adjust for those conditions on a quick and consistent basis, then a dry shot would work in my opinion.
Looks like i am looking into getting a wetshot nitrous setup for the NA.
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Well, I don't think any stock engine management system could handle that sudden of a change in O2 without any warning (such as intake P or mass flow going up) - its just that some engines are naturally more resistant to or tolerant of detonation so it doesn't matter as much.
Usually, stock ECU's of the late 80s thru 90's could only adjust fueling 15 - 20%; if you're running a 50 hp shot on a 150 hp engine, you'd need roughly 33% more fuel (more if you want it slightly richer for more cooling & detonation protection), which the ECU couldn't provide anyway. Plus, there's always a couple-cycle delay for the exhaust to reach the O2 sensor, for the sensor to react & tell the ECU, and for the ECU to start correcting. Plus, the knock sensor & circuit is almost worthless, so that can't even act as a band-aid until the ECU catches up.
It's not really a fault of the ECU, a 50 hp shot of nitrous is a bit more than it's been designed to take.
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So your saying that i should look into getting a new ECU in order to support a small nitrous shot?
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You just need a wet shot. Your ecu is fine.
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yea, the ECU is fine if you do a wet shot, I was just explaining why it couldn't account for a dry shot