Can I spray a 75 Shot without pulling timing?
08-02-2009, 06:08 AM
#1
Can I spray a 75 Shot without pulling timing? My full question is can I spray a 75 shot without pulling timing and using 93/110 Octane mix.
I have a dry setup on my car I finished hooking up. But, I have never sprayed since I have not had it to the tuner yet.
Just wondering what you guys think.
I have a dry setup on my car I finished hooking up. But, I have never sprayed since I have not had it to the tuner yet.
Just wondering what you guys think.
08-02-2009, 07:16 AM
#2
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I don't think you need to even go that far as mixing fuel octane. I can run a 75 shot on my little v6. Nitrous companies suggest pulling timing to be on the safe side, but a 75 shot is a tiny shot for an ls engine.
08-02-2009, 12:47 PM
#4
definately watch for detonation even on a 75 shot. for the most part it should be safe. but soon as it rattles back off of it. i run 28 degrees of timing in mine with a 75 hp shot with zero issues. however off the bottle it runs good enough to where i rarely ever hit the nitrous. if you plan on going bigger like to a 150 hp shot or so then i would just run some 104-116 octane in it just as a lil added insurance.
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08-02-2009, 04:22 PM
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I think the general rule is pull 2 degrees timing every 50 horsepower. It's not worth the risk by not doing so, especially with the larger shots.
Last edited by JScamaro; 08-02-2009 at 04:31 PM.
08-03-2009, 03:44 PM
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I ran 150 shot with TR6 plugs and no tune for over a year with out any problems, car still runs great. Air/Fuel ratio was great, just tuned up or down with the fuel jet till it's good. 
08-03-2009, 06:09 PM
#13
Sure you can run a 75 shot with out pulling timing. Here is why, the small shots can get way without pulling because, the cylinder pressure increase is not that great with 75hp shot, so the temps will stay reasonable. However, you will in fact get better volumetric efficiency if you pull a couple degrees even with the small shots. What that means is, your V8 air pump will work better with some timing pulled, granted it may be a small difference, but it still will be there. Also, if forget and put some reg gas in it you may get some detonation, so no safety blanket. Now with all that said, i have run upto a 150 hit with no timing pull and was fine. It's really what you are comfortable with and the dry hits can pull timing so easily many different ways that it makes no sense to me not to at least investigate, because you will be going bigger, no doubt about it, lol, we all have.
here's a little paragraph from my site to help understand why we pull timing on the spray:
[QUOTE Robert56]Nitrous increases the speed of the flame front, so you're bringing the advance back to properly time the pressure spike to the retreating piston. Meaning, preignition can occur, and lead to detonation with to much timing (stock and/or added advance). What this is saying is, the nitrous causes the cylinder to fire early, like when it's coming up on the compression stroke, this can do big time damage, and is prob the #1 reason the ring lands go. Also, you can see this early firing is less than optimal for ultimate power, and thus, not very volumetric efficient. You want it to fire at the time period when the piston wants to go down for the power stroke, not fighting an up traveling piston (preignition). I hope this makes sense, and if anyone else reading along has additional input or clarification, that would be great.[/QUOTE Robert56]
Robert
here's a little paragraph from my site to help understand why we pull timing on the spray:
[QUOTE Robert56]Nitrous increases the speed of the flame front, so you're bringing the advance back to properly time the pressure spike to the retreating piston. Meaning, preignition can occur, and lead to detonation with to much timing (stock and/or added advance). What this is saying is, the nitrous causes the cylinder to fire early, like when it's coming up on the compression stroke, this can do big time damage, and is prob the #1 reason the ring lands go. Also, you can see this early firing is less than optimal for ultimate power, and thus, not very volumetric efficient. You want it to fire at the time period when the piston wants to go down for the power stroke, not fighting an up traveling piston (preignition). I hope this makes sense, and if anyone else reading along has additional input or clarification, that would be great.[/QUOTE Robert56]
Robert
