Slowz28020189

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?

Nostang

iTrader: (4)

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.

Slowz28020189

Ahh gotcha! Well I guess I'll have to consider prepping for 11.5-1 the car will see driving on the street every once in a while and naturally I'll need to fill up if only I had a 110 octane Stantion near Chicago. If I did want any higher compression on pump gas I'd have to sacrifice the amount of shot I'm spraying then?

KW Baraka

iTrader: (7)

Mmmmm.......My '96 Impala = 12.5:1. I drive it on premium in 100*+ San Antonio heat with no detonation.

Jus' sayin'.....

Oh......I don't spray nitrous, BTW.

KW

98CayenneT/A

A stand alone fuel cell might be something you want to look into.

Heatmaker

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.

Nostang

iTrader: (4)

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.

CFLFORMULA93

hes got a secret stash of lt4 km that tune the car for him.

pantera_efi

iTrader: (1)

Hi Slowz, I have customers that run "dual-fuel" systems.
The common choice for WET NOS is another tank of Propane (130 octane) in the trunk.

Lance

KW Baraka

iTrader: (7)

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

Nostang

iTrader: (4)

The PCM will not pull timing without a knock sensor active in the tune so the PCM would never know you are detonating. I was asking if you were running some sort of knock sensors as I do not know of any knock sensors that work with solid rollers. My combo runs .026 lash hot so it has a lot of valve train noise. Not to mention the car is very loud so I would never be able to hear pinging or detonation. I am running 9.35-1 dynamic with 12.15-1.

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.

CFLFORMULA93

maybe you didnt get the joke but thats ok i got it in. dont want to skew too far off topic but im sure your good to go since you dont hear anything with the hood up....carry on with you big boy discussion