Author Topic: Nitrous on an NA  (Read 1285 times)

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Offline ~Groll69~

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Nitrous on an NA
« on: June 22, 2012, 10:03:44 AM »
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.
"Long Live Rotary"

An RX-7 is like having a slut as a gf! She will love you, but she will also screw around with the guy at the parts store, most of the local cops, your insurance agent, your apex seals, your bank account and your credit card!!!

Offline fidelity101

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Re: Nitrous on an NA
« Reply #1 on: June 22, 2012, 02:58:32 PM »
wet is safest and more consistent from what I've been told.

Offline ITSWILL

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Re: Nitrous on an NA
« Reply #2 on: June 23, 2012, 06:55:36 AM »
A 50hp wet shot will work perfectly. Buy it off of Craigslist.  Retard timing 2 degrees. Profit!!!
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Offline awfc3s

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Re: Nitrous on an NA
« Reply #3 on: June 27, 2012, 08:06:36 PM »
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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Offline ITSWILL

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Re: Nitrous on an NA
« Reply #4 on: June 28, 2012, 03:19:11 PM »
Nope, just quoting southpark "stage 1: Underpants. stage 2:????? Stage 3: profit.
86 Base LS1 w/100 shot
88 TII 20B T70 turbo

Offline toplessFC3Sman

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Re: Nitrous on an NA
« Reply #5 on: June 30, 2012, 07:09:43 AM »
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

Offline ~Groll69~

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Re: Nitrous on an NA
« Reply #6 on: July 02, 2012, 07:01:00 AM »
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.
"Long Live Rotary"

An RX-7 is like having a slut as a gf! She will love you, but she will also screw around with the guy at the parts store, most of the local cops, your insurance agent, your apex seals, your bank account and your credit card!!!

Offline toplessFC3Sman

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Re: Nitrous on an NA
« Reply #7 on: July 17, 2012, 08:12:46 PM »
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.

Offline ~Groll69~

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Re: Nitrous on an NA
« Reply #8 on: July 18, 2012, 12:47:21 PM »
So your saying that i should look into getting a new ECU in order to support a small nitrous shot?
"Long Live Rotary"

An RX-7 is like having a slut as a gf! She will love you, but she will also screw around with the guy at the parts store, most of the local cops, your insurance agent, your apex seals, your bank account and your credit card!!!

Offline ITSWILL

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Re: Nitrous on an NA
« Reply #9 on: July 19, 2012, 09:06:50 AM »
You just need a wet shot. Your ecu is fine.
86 Base LS1 w/100 shot
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Offline toplessFC3Sman

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Re: Nitrous on an NA
« Reply #10 on: July 19, 2012, 04:50:27 PM »
yea, the ECU is fine if you do a wet shot, I was just explaining why it couldn't account for a dry shot