nos on a 318

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duster731

duster731

young gun
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I'm thinking about doing a 125 shot set up on my engine and was wondering what do I need to do to the engine to set it up for nos... Will it cut the life of the engine in half, how much improvement will this give me.

I currently run 14.8 but I'm hoping I can get high 13s with my new top end I'm going to be doing... And then add a 125 shot do you think I could. Hit 12s.......
 
well, nitrous is a touchy subject to some people.... it all just depends on the motors condition, how much of a shot, and the tuning. theres the foolish out there who swear nitrous will grenade a motor unless you have forged pistons, good headbolts, good rod bolts, etc. which all of those do help on a motor, but if done right a 125 shot will work great on stock or mild bottom ends.

i have seen several ( and owned one) stock cast bottom end motors with nitrous run good, and be reliable. a few years back a buddy of mine bought a chevy malibu, with a other wise stock 350. upon tearing it apart for some inspection it was .30 over, 8:1 cast piston, stock 1.88 heads, .450 ish lift lunati cam, dual plane intake, 600 holley and it managed a shitload of nitrous passes. it ran high 8.20s in the 1/8th on a 150 shot of juice. but we knew what we had, the motor looked like it had several thousand miles since its last rebuild, we knew it would be reliable, and somethin fun to put the nitrous kit he had layin around on. that same motor went on to run for a season in my dads nova with a different top end with a 125 shot, and is still running today in my cousins malibu with the same untouched short block (however its only a matter of time before it blows, its startin to smoke a bit) but i couldn't tell you how many passes that motor's got on it lol.

where people screw up and give nitrous a bad name, they wanna put a 150 shot on a old questionable motor, most of the time its the tuning that causes it to blow, not all the time tho... if it were me, and i knew what i had, ( a decently fresh bottom end, and decent overall motor) i'd slap a 125 kit on a stock cast piston motor in a heartbeat. and i know a good mopar motor will take it cuz those blocks are motors are tuff. everything was touched on the 350 too as far as tuning goes, timing set back a couple "extra" deg. just to be safe, colder plugs, fuel pressure safety switch, good fuel pump.. etc. safe tuning, and a reliable size shot is the life of nitrous.

i would look into sumthin like a nos power shot kit its fairly cheap and its a straight 125 shot ( thats the only jets it comes with) .. plus if you don't have any of the other jets on hand you won't be as tempted to put on a bigger shot right away lol.
 
Tune up the car to run the best it can without juice, then add juice.

You have a bunch of stuff to work on before messing with the bottle.

Gearing on juice is different than without. The 3.91's you have might be good with juice, even with the taller tire.

If you do put the 125 on, pull 4* of total out of the ignition and make sure your fuel supply and plate jetting are appropriate and correct.
 
crackedback said:
Tune up the car to run the best it can without juice, then add juice.

You have a bunch of stuff to work on before messing with the bottle.

Gearing on juice is different than without. The 3.91's you have might be good with juice, even with the taller tire.

If you do put the 125 on, pull 4* of total out of the ignition and make sure your fuel supply and plate jetting are appropriate and correct.
Click to expand...

Hey, what happened?
She quit dancing.
 
The biggest danger is running lean. This WILL kill the motor with nos. I have heard a wet delivery system is safer than dry.

Theres a lot of folks feel a turbo motor should be built to the hilt too,but the truth is a turbo is actually very gentle on parts due to the cylinder filling method and when it happens.. Go ahead and use the nos,I wouldnt be afraid to!
 
I'd start out with a 125 shot to get it dialed in (after follwing Cracks' recommendation to optimize performance before stepping up to NOS.

If it were me, knowing how tough, and cheap, 318's are to build, I'd work on up to a 250 shot and stand on it.

Also, if you do get serious about NOS, MSD sells control boxes that allow you to automatically retard timing with rpms. Doing so prevents lean out and will result in better top end performance.

Have fun and let us know how it works out !

Southernman
 
Kool I'm glad you guys are on my side lol and not telling me not too.

Of course timing needs to be tuned down a couple degrees, a better fuel pump, and tune the carb would help...... My engine is fresh I built it myself and has about 5,000 miles on it. I appreciate your guys input it helped out a lot I believe my engine will do just fine with a 125- 150 shot atlesst till I can do a 360 build, so what would be the best kit to get other then the nos power shot is this a dry or wet kit? Thanks guys
 
duster731 said:
Kool I'm glad you guys are on my side lol and not telling me not too.

Of course timing needs to be tuned down a couple degrees, a better fuel pump, and tune the carb would help...... My engine is fresh I built it myself and has about 5,000 miles on it. I appreciate your guys input it helped out a lot I believe my engine will do just fine with a 125- 150 shot atlesst till I can do a 360 build, so what would be the best kit to get other then the nos power shot is this a dry or wet kit? Thanks guys
Click to expand...


sounds like you got a good foundation... the power shot is a wet kit. (any nitrous system that sprays fuel and nitrous in to the motor is considered a "wet" kit). the celonoids on the power shot is only adjustable to a 125 shot, if u just plan on havin some fun with your current motor, and keepin it simple i'd go powershot but if you plan on learning more and tinkerin with it to get the best overall performance, you might as well pay the extra and step up to sumthin like a cheater kit (its a overall better kit, with more jetting options). the celenoids on it are adjustable from a 50 shot all the way to 250. the cheater kit would be better suited to a bigger motor down the road too so it would payoff in the long run...

so when you buy the kit make sure your getting what you want, and what kind of motor its gonna stay on. other wise get the better kit, jet it down for your current motor, then later on you can have a wide range of options for future motors. all nitrous kits need some tuning, its no bolt on and go thing. also you got some good suggestions from others x2 on that msd retard control box, that thing makes it handy and simple.. you have to run a msd box for that tho...
 
Amazon is the cheapest so far with 320$ nos powershot kit but no inject plate. And 447$ for the cheater kit, I light as well and get the cheater kit for less then 100$ extra but it says its adjustable from 150-250 so there is know 125 shot
 
I don't know how you would run a dry kit on a carb car? Injected cars spray nitrous only into the intake manifold, while simultaneously spiking the fuel pressure to spray more out of the injectors, that doesn't really work on a carb car.

Anyways,

Most engines can take 125-150 if they're in otherwise decent shape. I think you'd have fun with it.

I'd say do it, but do it right. Start with the smallest jets and read the plugs as you do bigger shots. Running the right plugs (colder heat range, non projector electrode, not Champion) is important as well.

Intake manifold makes a difference too. I'd look for one of those old timey Holley single plane intakes (Street dominator I think its called).

Good exhaust flow is important to power production, as you've got a lot more to get out of the chamber.

Lean and/or halfass tuneup is what kills most nitrous motors-remember, the FUEL makes the power, not the nitrous- BUT there are other dangers too.

Nitrous creates enormous cylinder pressures, much more so than turbos or superchargers, and a cast piston or 40 year old bearings are only going to take so much. One way to help is to shift at conservative RPMs.

Consistent bottle pressure is the secret to success. A good bottle heater is a crucial part of a nitrous install.

Historically speaking, NOS kits are jetted very conservatively. Nitrous Xpress kits are more aggressive.

Run distilled water instead of antifreeze (always a good idea for a track car). If you blow a head gasket, antifreeze will eat the bearings in a hurry. Cools better anyway.

Have a fire extinguisher in the car.

Last but not least, even though if you do it right, nitrous can be a low risk affair, never put the bottle on anything you aren't willing to destroy.

Steve
 
Wow good info I read the whole thing :) lol sounds like I need to do start thinking about my build, so what your saying is a single plane will work better then a dual plane intake. I was going to run the edel rpm air gap, since nos needs fuel to work instead of a 650 dp should I get a 750 dp and do jet changing to it?
 
The NOS system has it's own fuel supply in your case separate from the carb. The carb has no bearing on how lean or rich the system will run. There are jets in the plate to set nitrous and fuel flow.

Too bad you weren't thinking about this a few months ago. Amazon had the cheater systems for $299.
 
Aaww man 300$ dam lol it might be two more months till I do this but what about the intake a duel plane or single plane
 
If I single plane has good distribution its way better than a dual plane. You have to tune for the leanest cylinder.

I'm also curious about which heads. I wouldn't run the street dominator with 340/360 heads.
 
Upgrading from stock heads to 188-160 swirl port heads and I'm gonna get them ported... Stock cr 77 engine I think around 8 to 1
 
duster731 said:
Amazon is the cheapest so far with 320$ nos powershot kit but no inject plate. And 447$ for the cheater kit, I light as well and get the cheater kit for less then 100$ extra but it says its adjustable from 150-250 so there is know 125 shot
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thats just the jets that it comes with (150 to 250), that doesn't mean you can only use it within that range. you can buy different jets seperately and jet it down to other sizes (50,75,100,125 etc.) but the max on that kit is 250, which is plenty even for most race small blocks, but the big guys get into foggers and 2 stage kits with the big solenoids that allow up to a 500 shot. just save up and buy the cheater, and buy either the 75 or 100 shot jets seperate to go with it (up to you, but i'd start off with a 100) , you can start with that then work up to 150.
 
Yes but Idk if I want the air gap now since a single plane would be better for the bottle
 
So for this subject since I'm getting closer to be throwing on my 302 heads should I get a single plane int or the edel air gap? Even if the bottle isn't gonna be on the engine for a while will the single plane be good for the streets..

And I'm also add the comp xe268 cam,650 dp along with the heads and intake
 
duster731 said:
So for this subject since I'm getting closer to be throwing on my 302 heads should I get a single plane int or the edel air gap? Even if the bottle isn't gonna be on the engine for a while will the single plane be good for the streets..

And I'm also add the comp xe268 cam,650 dp along with the heads and
intake
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i would go ahead and get a single plane if i had the extra cash, but if not nitrous will work with dual plane too, just not quite as good. depends on what kinda single plane you get, i would look around for sumthin of the low rise type for a lot of street driving, plus its a 318 so you cant get too wild or you will lose a lot of bottom end. a holley street dominator with some port cleanup would probably be perfect for your setup. look around on ebag, i saw 2 street dominators, and a ld4b on there last night. i thought about biddin on 1 of the holleys, but i already got 2 on the shelf lol.
 
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