ThumpnZ28

iTrader: (23)

I'm nearing the end of my forged engine build. This build was done FOR a bigger (150-200) shot of gas. The rings are gapped for nitrous, and I'm running head studs. My questions: being that my engine is 11.5:1, is there a limit to how much nitrous the engine will handle? I wanted the higher compression for better NA performance. I already know that race gas will be a necessity. What about spark plugs? I ran a 100 shot for a long while with Tr6 plugs, and my friend a 150 with no plug issues for either of us. Any help that the community can offer would be a great help.

87silverbullet

iTrader: (11)

First, in the LS world lately 150-200 shot is the norm. Anything more is considered a big shot. Guys have been spraying on 11.5:1 like its an everyday thing, it won't be a problem. TR6 is a big NO, you need to get some br7ef plugs or even step up to an 8

Just an FYI there are guys on 300 shots on stock bottom ends here so you really didn't have to forge it if you are only going to go with 150-200 shot of gas.

Neal@NitrousOutlet

Your going to be perfectly fine on the bottom end. Plug choice does need to be br7's not tr6's. I wouldn't want to see a new motor be damaged by tr series plugs.

Cant wait to see some results

dnkynrbk

iTrader: (34)

True stated above

ThumpnZ28

iTrader: (23)

My buddy's car wouldn't idle for beans on the br7 plugs. Why is that and how can I remedy the no-idle with my car?

87silverbullet

iTrader: (11)

My car idled fine with the BR7 plugs in it. Did you make sure all the wires were on tight?

ThumpnZ28

iTrader: (23)

I guess I will give them a try. Yes, all the wires were tight. What kind of fuel do I need to be using? I run 93 on the street now with the stock engine, but I need to make sure I don't detonate on the spray with the higher compression .

Orr89rocz

iTrader: (13)

how was the tune on them? Too rich and too cold a plug could foul so you may need to run it leaner at idle. I never had a problem with 7 heat range plugs on my sbc's but that may be a different animal. I got 8's on my low comp turbo motor and it idles fine even with 115lb injectors

You can mix some race gas in it, but you may not need it if the tune up is good. I know my buddy sprays 250 hits all day on 93 oct but he did melt a plug because timing was to high and it leaned out abit...never really detonated just melted the strap off the plug and nicked the pistons up. So be careful with the timing and air fuel mixtures

ThumpnZ28

iTrader: (23)

Great. Man, thanks for the info. Thanks to all. Kinda hoping others will step in too.

Fbodyjunkie06

iTrader: (10)

Make sure the idle AFR is in the mid 14's at the least for the best idle on the colder plugs.

You may even need to bump the timing up 2-4* in the idle cells to get them to idle right.

Mine idles on B8EFS and B9EFS fine, but only after I leaned the idle up from high 13's to mid to high 14's, just listen for cam run on in the sound of the exhaust from being to lean at idle. It will sound like the cam doesn't want to drop back into a lope. Takes a keen ear to be able to hear this.

Race gas and colder plugs will always eventually foul so you will have to replace them after each outing at the least. Certain things come with nitrous motors this being one of them.

I wouldn't worry on the nitrous shot size until you get up around 275-300 and then as long as the tune is right and you are diligent and good at reading plugs you won't have anything to worry about. I've run a rated 200-300 shot on my stock bottom end with no problems albeit at 10.32:1 compression.