[v8mazda]

i'v heard this two ways about no2. someone told me running a 50 to 100 shot without forged would'nt do any damage. heard it also the other way that it would round the edges of the rings ... doing damage. does anyone know the truth? i have a built 403 and would love to be able to use a 75 just for the occasional thrill but not if it means messing up this motor. any info would be great. thanks

[DoubleVision]

If nitrous isnt run properly it will do damage in any engine. This means being sure the fuel curve and ignition is correct. a 75 horse shot is commonfold on stock engines, I dont see why it would hurt your 403. Will it cause increased wear? likely since theres more going on in there. However, this also reflects on what shape the engine is already in, if its got high mileage on it, Nitrous isnt for you. If its a recent rebuild and in good shape it should be fine providing the tune is in the correct state.

[v8mazda]

thanks for the tips. the engine was rebuilt in 2006 and it was a pretty good build. as far as tuning any suggestions? from what i read i need to make sure i have enough fuel and my plugs need to be a couple degrees cooler then called for. but would that hurt my normal driving going with a cooler firing spark plug? thanks again

[bigbadbowtie]

How much compression is in the engine now? What did you use for pistons?

75 shot should be no big deal as Double said. You should be able to run 75 shot on stock heat range plugs if your not already on the edge of detonation.
I would step down 1 range just for a safety margin.
Most important part of this is to read the manufacturers instructions and then read them again and then again.
Basicly...Pull 1-2 degrees of timing per 50 hp, make sure you have adequate FLOWING fuel pressure, don't spray below 3k and be prepared to be HOOKED.

You say you will only spray it on occasion. That will last 1-2 hits and then you will be filling that bottle more than you thought. I guarantee.

[v8mazda]

i have the keith black pistons in it so i think compression is 9:1. as far as the timing goes. you said degree it back 1 or 2, this sounds stupid of me but whats that mean lol lol i mean i know theres the timing light and turn the distributer timing but is'nt there also degree the cam it self physically? just so i dont mess this up and i dont think i'll use this nitrous to often. i live michigan so i only have a few good months of driving and i'm sinking a small fortune into this paint job so i'm going to be a little scared to drive down the road when misquitos are out my wife is really into this project with me as well and we're trying to make it a car show kinda car. we're having a blast to thanks for the input guys.

[johnnyblaze]

when it comes to a 75 shot,thats pretty mild,just make sure your fuel pressure is a verified 5.5 psi,if that requires a fuel pump and regulator,so be it,thats at wide open throttle,carburated of course,start with 4 degrees of timing out,and should be ok with 3 degrees,dont spray under 3200,and be sure to check your plugs after the first couple runs,you dont wanna see a whiteish plug,nitours is fun if not abused (in every aspect),and if your set up right,for the occasional hit that you speak of you should be fine,stock 305 edelbrock plate system,i only changed the motor for a better one,motor was still healthy after a summer of hittin spray,and coincidentially a 75 shot,that was as big as i would go for my stock motor,juss my 2 cents

[v8mazda]

johny thanks for the info. i'll make sure i have a regulator for this set up then.

[1969NovaSS]

I'm curious, what happens when you spray below 3k rpms?

[v8mazda]

ya i was woundering the same thing......

[Stroke]

The most profound effect is instant HP. The other parts of the engine will surely be affected by this bottle feeding, depending on how wisely you use it.

i have the keith black pistons

Exactly what KB piston are you referring to? I've seen guys hose hyper pistons before, but I'm not that brave.

About that 3000 deal. Arm the system and when you put 'er to the wood, you're on! You're going to be adding instant HP, instant TQ, any parts not up to snuff will let you know it. Had a buddy whose NOS kit leaked down on him. When he went to start his car, it blew the entire manifold off and thru the hood.

[v8mazda]

i'm not sure which(kb) ones they are. the guy i got the car from did the biuld in 2006. when i but the kit i'm going to make sure i buy everthing needed to do this right. if they say i need what ever to gaurantee performance and not harming the motor then i will get it. the nitrous is going to be more for the show and theme of the car anyway. i mean ya i'll use it here and there but it really will be rarely used. my wife and i are going all out on this car. custom upholstry to match that painjob, nice stereo etc. all the fun stuff. it's rare that my wife show any interest in my toys lol lol so i'm taking advantage of this one since she likes it and in the end if the nitrous kills the motor then i'll have fcr build me a better one with forged internals. i just have to find a buyer for my kidney on ebay........... you can get pretty good money on there for a good organ lol

[bigbadbowtie]

V8 - pull timing at the distributor. If your running 32 degrees of timing total, back it down 2 degrees per 50 HP.

I have run as much as 175 on Kb hypers but you really need to know what the ring end gap is on your current setup. Even in an N/A setup they require much more ring end gap then a normal cast or forged piston.

as far as spraying below 3k... I have sprayed 150 hp jets at 2500 with no ill affects but that is with a loose converter.
The deal with spraying below 3k is you really dont have enuff port velocity (CFM consumption) at low rpm so the charge kinda just sits there or even backs up in the intake. Thats why you see nitrous backfires on occasion at the "hit" of the kit.

[v8mazda]

thank you bowtie, i learned something new. as far as the ring end gap. i just replaced the headgaskets last weekend at the paintshop and just used some cheap gaskets as i just wanted to be able to move it around. but when i get it back i'm pulling the motor to do some other things and clean up the engine bay. so when i have it out i'll check on the ring end gap. and take my time with all this. thanks a ton for the input everybody.

[bigbadbowtie]

V8...here is a sheet that shows how to calculate the amount of ring end gap you need for KB hyper pistons per application.

http://kb-silvolite.com/clearance_pop.php

Good luck and let us know how it goes.

[v8mazda]

cool thank you. you guys rock