Pistons

What brand piston and compression ratio is good for a ltx 383 with spray. I know I need forged.

It depends on what you wanna pay. Diamond and JE are both at or near the top of the list as far as quality and price... nitrous and compression go well together. Your compression ratio depends on what kinda gas you want to run. On premium upper 11's to low 12s would be ideal

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I want around 12.1 but I want to be able to run pump gas. Been looking a t probe pistons or srp.

Are you planning on Meth or alky?

I am at 12.15-1 comp on my 383 and everyone I talked to said it is not safe to run pump gas on the setup with today's pump gas variability batch to batch and inconsistent mixes. I was recommended to run Sunoco 109 on my car and it seems to run great on the gas (not to mention, smells great). However, the price of race gas is much more than pump so that is a disadvantage along with limited driving from your "fill" station. I am able to run pump gas as is but I need to pull timing and I would not risk any WOT runs on the pump gas. It could be fine but I am not willing to risk it. If you want to be 100% sure you can run on today's pump gas I would keep compression under 11.5-1.

What is the ideal compression ratio for 93 non ethanol for mainly a street car.

I would stay under 11.5 with an LT1 and under 10.5-1 with old sbc.

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Originally Posted by Nostang 96z

I am at 12.15-1 comp on my 383 and everyone I talked to said it is not safe to run pump gas on the setup with today's pump gas variability batch to batch and inconsistent mixes. I was recommended to run Sunoco 109 on my car and it seems to run great on the gas (not to mention, smells great). However, the price of race gas is much more than pump so that is a disadvantage along with limited driving from your "fill" station. I am able to run pump gas as is but I need to pull timing and I would not risk any WOT runs on the pump gas. It could be fine but I am not willing to risk it. If you want to be 100% sure you can run on today's pump gas I would keep compression under 11.5-1.

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I ran 91 octane fuel in my 12.1:1 compression 383 LT1 for years, never had a problem. Ran a 100 shot at the track. That motor had 215 psi cranking pressure :D
LT1's can handle a decent compression ration with the reverse flow cooling.

I'd run high 11 to 12:1 compression on a street driven nitrous car on pump fuel.

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Originally Posted by GuillaumeC

I ran 91 octane fuel in my 12.1:1 compression 383 LT1 for years, never had a problem. Ran a 100 shot at the track. That motor had 215 psi cranking pressure :D
LT1's can handle a decent compression ration with the reverse flow cooling.

I'd run high 11 to 12:1 compression on a street driven nitrous car on pump fuel.

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I thought the same as well when building my combo but have been told otherwise due to the quality of pump gas today. I was really pissed to find that I had to run race gas in my setup. I will have the check my cranking compression to see where I am at. However, I would still be scared to run WOT on pump gas with my setup. I have ran pump gas cruising and it was fine but I also have a 5500 stall converter so the load was not too high. I did talk to Lloyd Elliot about it and he agreed that race gas was the way to go with my setup and that I could run pump gas if I pulled timing across the board on the tune but that would reduce power by ~40hp or so.

Quote:

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Originally Posted by Nostang 96z

I thought the same as well when building my combo but have been told otherwise due to the quality of pump gas today. I was really pissed to find that I had to run race gas in my setup. I will have the check my cranking compression to see where I am at. However, I would still be scared to run WOT on pump gas with my setup. I have ran pump gas cruising and it was fine but I also have a 5500 stall converter so the load was not too high. I did talk to Lloyd Elliot about it and he agreed that race gas was the way to go with my setup and that I could run pump gas if I pulled timing across the board on the tune but that would reduce power by ~40hp or so.

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11.5:1 is a little on the conservative side. As long as you have the afr dialed in correctly 12.1-12.5 is not out of question. I have helped a friend tune his 12:1 setup on pump gas with up to a 200 shot of nitrous.

i personally run 11.7:1 N/A on premium 91 octane gas... every day, data logs show no timing retard on long WOT pulls even in the heat of the summer...