High compression and 250 shot bad idea?
Thread Starter
Teching In
Joined: Aug 2017
Posts: 14
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High compression and 250 shot bad idea? Hey guys so Iv tried looking for a definite answer but a lot of mixed reviews on the subject. I'm building a 383 lt1. I like the idea of a nice high compression motor for a weekend warrior. So I'm curious on running a two stage 250 shot but will running high compression be it's kyrptonite?
Just make sure your timing is right and you have enough octane for the shot and compression you are running and you will be fine. Unless you want to run race gas all the time, you should opt for a compression ratio no greater than 11.5-1 and a dynamic compression ratio under 8.3-1 to be safe on pump gas without detonation. Lastly, make sure your rings are gapped for the shot you plan to run. It should roll out.
Thread Starter
Teching In
Joined: Aug 2017
Posts: 14
Likes: 0
Just make sure your timing is right and you have enough octane for the shot and compression you are running and you will be fine. Unless you want to run race gas all the time, you should opt for a compression ratio no greater than 11.5-1 and a dynamic compression ratio under 8.3-1 to be safe on pump gas without detonation. Lastly, make sure your rings are gapped for the shot you plan to run. It should roll out.
Jus' sayin'.....
Oh......I don't spray nitrous, BTW.
KW
Launching!
Joined: Sep 2005
Posts: 270
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If you're building the motor and you want to take in big shots like that use Nitrous Pistons period. Reason being 100 is okay on stock styled pistons, 150 is pushing it but 200 and up you need to go with a piston that can handle it. JE & Diamond Pistons make them for the LT1/SBC just for taking big hits. The CR varies but you can call them and tell them what you want and they'll tell you exactly what to use. You only kyrptonite things when you try to push your engine to do things that it wasn't built to do.
Last edited by Heatmaker; Sep 7, 2017 at 12:07 AM.
How do you know you are not getting any detonation? Are you running knock sensors with a solid roller cam? Do you go WOT on pump gas or run a different tune for pump gas? Just curious as I do not have it in me to risk popping a piston.
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On The Tree
Joined: Feb 2015
Posts: 159
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I wish I had the nuts to try it out on my setup. I actually planned to use pump gas (N/A at least) on my setup when I was putting it together but was told otherwise by a bunch of different reputable tuners. I have run pump gas idling and putting around but never at WOT.
How do you know you are not getting any detonation? Are you running knock sensors with a solid roller cam? Do you go WOT on pump gas or run a different tune for pump gas? Just curious as I do not have it in me to risk popping a piston.
How do you know you are not getting any detonation? Are you running knock sensors with a solid roller cam? Do you go WOT on pump gas or run a different tune for pump gas? Just curious as I do not have it in me to risk popping a piston.
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Knock sensors? We don't need no stinkin' knock sensors!
...... 
Oh, OK.....I see you got jokes.......
But if you were really a smart guy, you'd know I have no longer have a need for such things.
Now run on back to the sand box with the kiddies and leave this discussion to the big boys.
KW
My tuner tells me it's runs clean....and the ECM's not pulling timing at WOT or under load. LLSR, and I hardly hear a thing idling, spinning the engine in park with the hood up or going WOT on the highway. Dynamic compression is right at 8.8:1 so it's not that radical at all when you come down to it.
Knock sensors? We don't need no stinkin' knock sensors! ......
KW
Knock sensors? We don't need no stinkin' knock sensors!
...... KW
8.8-1 dynamic is still pretty high but doable for pump gas with a good tune. I would think you would not be able to hear any detonation at WOT unless you are running stock style mufflers. I would be curious if you find any signs of detonation if/when you pull the engine apart for refresh/mods.
BTW, watch your summer/winter gas fluctuations. I have talked to refinery engineers about fuel differences and was told the summer gas is better for performance cars as it has a higher vapor pressure and is a little more resistant to detonation. They start to transition in Sept to the winter gas.
On The Tree
Joined: Feb 2015
Posts: 159
Likes: 0
My tuner tells me it's runs clean....and the ECM's not pulling timing at WOT or under load. LLSR, and I hardly hear a thing idling, spinning the engine in park with the hood up or going WOT on the highway. Dynamic compression is right at 8.8:1 so it's not that radical at all when you come down to it.
Knock sensors? We don't need no stinkin' knock sensors! ......
Oh, OK.....I see you got jokes.......
But if you were really a smart guy, you'd know I have no longer have a need for such things.
Now run on back to the sand box with the kiddies and leave this discussion to the big boys.
KW
Knock sensors? We don't need no stinkin' knock sensors!
...... Oh, OK.....I see you got jokes.......
But if you were really a smart guy, you'd know I have no longer have a need for such things.
Now run on back to the sand box with the kiddies and leave this discussion to the big boys.
KW