Need a check on my Nitrous Barracuda setup

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Brandt Fonda

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Hey guys been reading up on Nitrous applications on the forum and internet, I believe I have got a good setup and was hoping some of you more experienced guys could give me a peer check and make sure I'm not missing something. I'm wondering if it would be "safe" to run a 150 shot on 93 octane pump gas with my setup?

360 la, 9.8:1 CR, forged pistons gapped 30, stock rods/crank, bored 40, Hughes engine cam 546/563 duration 236/242 108 lsa, 308 heads 202/160 multi angle with some mild porting/polishing work, Hughes roller rockers, M2 intake, TTI 1 3/4 headers, TTI 3" x-pipe, Holley Sniper 4150 TBI, Holley dual sync distributer (controls timing), Sniper NOS plate w/150 jet. Champion RN11YC plugs. Drivetrain: A833 32 spline 4 speed, 8 3/4 409 rear end w/ Eaton Tru trac and 3.91 gears.

min/max rpm NOS activation: 3k/6k Main engine rpm limit: 6200
Lean cut: 14:1 Rich cut: 10:1 Closed loop while NOS active: 12:1
4 degrees initial timing retard increasing to 5.4 degrees by 10sec (10sec max NOS duration)
45lbh fuel enrichment
 
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Sure, Why not!

Start with a richer fuel jet and dial it in! 10 sec is a long time though!

It is loads of fun and good luck! If you are just looking for a kick in the pants!

I have lots of this stuff laying around I no longer use from the late 80's! Used a 2 stage 150 on each system in the 80's. My motor survived it to this day without rebuild.

NOS is rarely repeatable for bracket racing though! More of an all, have your fun and smile deal! JMO!
 
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Honestly I don’t see a whole lot wrong with your tune. Make damn sure your fuel system is up to the task of supplying both the nitrous and the engine at WOT with a hefty margin for error. Watch the afr and don’t run lean, ever.
 
Might be pushing it with the 93 octane.. but your static compression isn't crazy high. Other than that, everything else sounds shiny.
 
I would top it off with a splash of 110 leaded until you get the hang of things.

You need to switch the plugs out to a non projection tip. I would have to look up the number for a 5/8" extended reach plug. NGK is your best bet.

I would waint to turn the kit on until at leasr 3800 rpm. You don''t want to lug the engine spraying. Turning the kit on at too low an rpm is a recipe for disaster. You don't want a nitrous backfire and definitely don't want to beat the main bearing out of the block.

Target AFR on spray is going to be more like 12.8-13.2. 12.0 is way rich spraying.

What are the ring gaps set at?
 
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I tried the the setup I had, did 3 hits. One in 2nd gear and two in 3rd, seemed to do pretty good. Broke traction in second tho gonna need more tire.

Might be pushing it with the 93 octane.. but your static compression isn't crazy high. Other than that, everything else sounds shiny.

Yeah I was a little worried with about the 93 octane, I wound up putting a can of that race gas octane booster in and it seemed to do good.

I would top it off with a splash of 110 leaded until you get the hang of things.

You need to switch the plugs out to a non projection tip. I would have to look up the number for a 5/8" extended reach plug. NGK is your best bet.

I would waint to turn the kit on until at leasr 3800 rpm. You don''t want to lug the engine spraying. Turning the kit on at too low an rpm is a recipe for disaster. You don't want a nitrous backfire and definitely don't want to beat the main bearing out of the block.

Target AFR on spray is going to be more like 12.8-13.2. 12.0 is way rich spraying.

What are the ring gaps set at?

I have a photo of the plugs I have in there, I feel like they are non-projected. When I checked them right after the hits they had an orange coloration to them, except #8 and it looks like the one in the picture. I can't use leaded as I have O2 sensor would VP MS109 be good? I will work on the tune and bring the NOS on at 3800 seems like a small window (3800-6000)? and I will take closed loop to 12.8 AFR. Think I should tighten up the NOS AFR limit cuts to a more narrow band? Engine was built with NOS in mind, forged pistons,.030 ring gap and floating wrist pins.
plug.jpg
 
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the orange color is from the octane booster.. which absolutely kills any chance of an accurate plug read. Probably better mixing in some race gas instead of the octane booster. then make a lick, shut 'er down and pull the plugs.
 
I'd use some MS109 for certain. No octane boosters for this guy. Those plugs do look like non-projected tip.

As far as RPM range....how far do you expect it to fall back between gears shifting at 6k? I'd hope it stays above 4000? Forgive me, I am a 4-speed guy so there might be some ignorance to what happens when a gear is missing.
 
I tried the the setup I had, did 3 hits. One in 2nd gear and two in 3rd, seemed to do pretty good. Broke traction in second tho gonna need more tire.



Yeah I was a little worried with about the 93 octane, I wound up putting a can of that race gas octane booster in and it seemed to do good.



I have a photo of the plugs I have in there, I feel like they are non-projected. When I checked them right after the hits they had an orange coloration to them, except #8 and it looks like the one in the picture. I can't use leaded as I have O2 sensor would VP MS109 be good? I will work on the tune and bring the NOS on at 3800 seems like a small window (3800-6000)? and I will take closed loop to 12.8 AFR. Think I should tighten up the NOS AFR limit cuts to a more narrow band? Engine was built with NOS in mind, forged pistons,.030 ring gap and floating wrist pins.View attachment 1715758004


That plug is a projected tip. That’s what the Y stands for.
 
I'd use some MS109 for certain. No octane boosters for this guy. Those plugs do look like non-projected tip.

As far as RPM range....how far do you expect it to fall back between gears shifting at 6k? I'd hope it stays above 4000? Forgive me, I am a 4-speed guy so there might be some ignorance to what happens when a gear is missing.
No you are right (I am a 4 speed as well) the rpm drop is not going to be down to 3k, I meant on the initial hit I thought coming in sooner would be better but in the overall scheme of things your only gonna lose that 800 rpm once.

That plug is a projected tip. That’s what the Y stands for.

I think you are right the Y is not technically the least projected I believe H is? But Y is definitely not projected at .060-.090?
 
No you are right (I am a 4 speed as well) the rpm drop is not going to be down to 3k, I meant on the initial hit I thought coming in sooner would be better but in the overall scheme of things your only gonna lose that 800 rpm once.



I think you are right the Y is not technically the least projected I believe H is? But Y is definitely not projected at .060-.090?

Non projected vs projected tip

20210629_173052.jpg


20210629_173157.jpg
 
Is that NGK plug a good pick for my setup? The 9 is pretty cold compared to OE 14?
 
Is that NGK plug a good pick for my setup? The 9 is pretty cold compared to OE 14?

I dont think champon to ngk heat ranges coincide. In NGK-ese a stock plug is xr5...colder is a xr7 as an example. 300 shot and we are in 11-12 heat range. Again this is NGK land. There must be a cross reference out there somewhere.
 
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