New to Nitrous

Mattcleaver

Daily Driver
Apr 20, 2020
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0
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Hello!

This is my second time on this forum and the first time, y'all helped me fix a pesky oil leak on my buddies and my 1980 malibu street car. For context, we're two 19 year olds who love cars and rebuilt his blown (cracked piston) small block into a respectable 383 stroker sbc in his dads living room. The motor has a holley street avenger 650 cfm vacuum secondary carb (which we plan to swap), speed pro pistons, scat rods, arp rod bolts, comp cams camshaft, liberty performance rockers, and dart iron eagle heads. This summer we were happy to finally take it to the track and after adding slicks, the car ran a 12.71 @ 113 mph in the 1/4. We were happy with it just making a pass but I'd say those numbers aren't horrible for a couple of newish guys to the sport on a budget. That being said, we obviously want to go faster as anyone would. Neglecting the fact that we grenaded the th350 the last time at the track, were looking to step into a REASONABLE nitrous kit. Maybe a 125 or 150 shot? The car is running roughly 9.2:1 static compression ratio with acdelco r43 plugs. The ignition system is an MSD Pro Billet with an MSD ignition box running it (currently set at 15 degrees base and 32 degrees total). We're thinking just a plate system under the carburetor. I want to ask y'all who obviously have more experience with this stuff than we do, what you guys recommend and some tips. I'm assuming the basics like a wideband sensor to be safe and retarding the timing and all but I'm still nervous. We've invested too much of our limited time and money (being full time college students) in this car to melt it down first pass. I just want to hear what you guys have to say. Thanks in advance!

Matt
 

shoedoos

Amateur Racer
Jan 10, 2008
143
3
18
First thing to do is find out where you can fill bottles locally and at what cost. Second would be to trawl facebook and craigslist for a used kit. Third thing to do is buy rebuild kits for the solenoids (yes they are a simple fix). 4th will be to baseline your 383's best performance without nitrous. 5th is to add a small shot (50hp) and learn what it does to the car's performance, not only engine but driveline and suspension as well. 6th is to step up from there after you iron out the weirdities that nitrous does to your car. My experience is that Speed Pro forgings and a low compression ratio are forgiving when it comes to nitrous. Once you understand and enjoy nitrous tuning (not hard at your level), it will be addictive and you won't want to run your car N/A ever again....expect a very big jump in performance and a diving timeslip once you start throwing jets at the kit you use.....
 
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Mattcleaver

Daily Driver
Thread starter
Apr 20, 2020
13
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First thing to do is find out where you can fill bottles locally and at what cost. Second would be to trawl facebook and craigslist for a used kit. Third thing to do is buy rebuild kits for the solenoids (yes they are a simple fix). 4th will be to baseline your 383's best performance without nitrous. 5th is to add a small shot (50hp) and learn what it does to the car's performance, not only engine but driveline and suspension as well. 6th is to step up from there after you iron out the weirdities that nitrous does to your car. My experience is that Speed Pro forgings and a low compression ratio are forgiving when it comes to nitrous. Once you understand and enjoy nitrous tuning (not hard at your level), it will be addictive and you won't want to run your car N/A ever again....expect a very big jump in performance and a diving timeslip once you start throwing jets at the kit you use.....
I appreciate the reply! I guess working our way up to bigger shots is definitely the way to start out. We were looking at some reasonable NX plate systems that can be jetted for 100-250 shot. Runs about $423 on summit. First off, can we run 93 octane on an eventual 150 shot? Also, what plugs would you recommend? r43's are nice and cold so hopefully they'll work. Also, I've heard numbers such as pulling 2 degrees of timing per 50hp. Is that a reasonable spot to start? Also, the system is a wet system so should the carb need to be rejetted? Or will the wet system provide enough supplemental fuel? Thanks in advance for all the input!
 

shoedoos

Amateur Racer
Jan 10, 2008
143
3
18
Very little goes wrong on a plate nitrous kit.....plungers in the solenoids wear and that's about it......I wouldn't waste money on a brand new kit if I could find a used one and restore it with the easily (and cheaply) available parts.

As far as fuel quality and plugs are concerned, you need to tune your engine N/A to its best performance before stepping up. While doing that tuning, you will learn how to read plugs and they will tell you what you engine wants as far as fuel and heat ranges are concerned.

At entry level (50hp nitrous) I doubt you have to change either plugs or fuel. But you need to read your plugs and A/F meter to know for sure.

As far as re-jetting is concerned, this comment does show a little naivety on your part. The fuel enrichment side of a wet nitrous kit has nothing to do with the carb. That's why I mention sorting the tune in N/A form first. The fuel/nitrous ratio is all dealt with in the plate. Each side of the plate has jets, one for the nitrous and the other end for a fuel jet.

As far as feeding fuel to the plate, my suggestion is to run a secondary feed line, fuel pump and regulator from your existing fuel tank to supply the nitrous kit. Yes, you can initially tee into the existing fuel line but if you want to step up, then the additional fuel line will eventually become a necessity. Save by buying a used nitrous kit and use the left over money to buy another fuel system is my advice....

With regard to the timing retard, that generic 2-degrees for each 50hp is very subjective - once again, reading plugs will tell you what your engine wants....
 

Mattcleaver

Daily Driver
Thread starter
Apr 20, 2020
13
0
1
19
Very little goes wrong on a plate nitrous kit.....plungers in the solenoids wear and that's about it......I wouldn't waste money on a brand new kit if I could find a used one and restore it with the easily (and cheaply) available parts.

As far as fuel quality and plugs are concerned, you need to tune your engine N/A to its best performance before stepping up. While doing that tuning, you will learn how to read plugs and they will tell you what you engine wants as far as fuel and heat ranges are concerned.

At entry level (50hp nitrous) I doubt you have to change either plugs or fuel. But you need to read your plugs and A/F meter to know for sure.

As far as re-jetting is concerned, this comment does show a little naivety on your part. The fuel enrichment side of a wet nitrous kit has nothing to do with the carb. That's why I mention sorting the tune in N/A form first. The fuel/nitrous ratio is all dealt with in the plate. Each side of the plate has jets, one for the nitrous and the other end for a fuel jet.

As far as feeding fuel to the plate, my suggestion is to run a secondary feed line, fuel pump and regulator from your existing fuel tank to supply the nitrous kit. Yes, you can initially tee into the existing fuel line but if you want to step up, then the additional fuel line will eventually become a necessity. Save by buying a used nitrous kit and use the left over money to buy another fuel system is my advice....
I'll have to look into used kits as I never have before. We already installed an AEM wideband O2 sensor and gauge. We have the car tuned to run about 12.5:1 N/A at wide open throttle. I guess it makes sense that the plate (being that it is a wet system) takes care of the extra fuel to accommodate the nitrous. I'm probably over thinking this, just alittle paranoid as I have literally never installed, tuned, or run a nitrous system in my life. I've always run N/A. Thanks for the advice. I'll look into it.
 

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