ok a couple questions here:
what is the max safe boost a LT1 block can take?

what should the compression be on a 383 for either a S/C or a Turbo or Twin Tubro?

which would be better for a daily driver, S/C or TT/T? i was thinking turbo since i could have a boost controller and drop the boost when not at the track?

what the biggest shot of nitrous that could be used safely on a blown engine?

thanks

 

theres a ton of info flyin around this board, so th things i can't answer you may wanna do a search on, and even the things I can answer Im sure there's guy with other opinions....

anyway, the Lt1, in my opinion cannot handle ANY boost safely. The fact of the matter is it is a 10.5:1 CR, and 2 bolt main motor. Guys have run 6# S/Cs with some "reliability" but in the long run it takes years off the motors...

As for daily driveabliliy I would say single turbo. With a single turbo (if you are looking to make big power) you will use a larger turbo that won't spool *quite* as fast as two smaller, twin turbos. So, if you only use the lower RPM range you can make little or no boost and retain your gas mileage. With a blower, its always putting drag on the crank, always making some boost.

As for the comp ratio, depends on the application but most FI cars are probably like 8.5ish:1

 

There are several people who have run the LT1 block to 25+ PSI and over 1000 rwhp. The block itself is pretty strong.

I'd shoot for the lowest compression you can afford. It's quite possible to get the compression down around 7.8:1 or so if you go with aftermarket heads, dished pistons, and custom gaskets. It just ain't cheap. Most people shoot for 8.5-9:1 for a street motor.

I doubt there's really a "better" option. Just different ways to get things done. The turbos will require more fabrication and produce more underhood heat. Most blowers are fairly simple to install and they stay relatively cool. As for blowers always making boost, that isn't entirely accurate. Yes, the impeller is always spinning in a supercharger, but the same is true for the impeller in a turbo. Since most superchargers use a bypass valve, the extra air flow created at cruise isn't forced into the motor so it will actually run in a vacuum at cruise/light throttle.

With the nitrous, I'd probably stick with a 50-75 shot for a blown car. It'll make more power than that anyways.

Also, a blower does not take "years" off a motor. People not taking care of their cars or not being careful is what causes 99% of all blown motors to pop. I pulled the supercharger off my car a few weeks ago and did a compression check, 180-185 PSI of cylinder pressure after 40k miles with a Vortech S trim and 90k miles total.

 

didn't realize he was only talking about the block, my bad. when i said years i was talking about the stock LT1 motor, not a LT1 block with a new rotating assembly...
As for the supercharger...it's always putting extra drag on the crank though, regardless of if the car is actually using the boost or not, so for daily driving woulndt that hurt gas mileage a bit?

edit: The LT1 block can also be strengthened by getting the block filled, not sure how much more power it could handle but...

 

if i get what i want built, it will be a all forged 383, not sure if im gonna go S/C or turbo, dont know alot about either yet so i wanted to get yalls opinions.

 

No one really knows. I am building a 355 with a 2 bolt block now. Going 4 bolt splayed billet caps on ALL the caps, including the front and rear mains. Also going block fill and building a custom main cap girdle, but this girdle is designed like the buick GN girdles which are bolted to the oil pan rail. I think this block could take 1300-1400+rwhp or so.

Jose

 

Interesting Jose. I'd love to see some pics of that main girdle. I went with billets on the 3 center caps myself.

 

I will post up pics if we get it all finished up. Right now its all be entered into the CNC machine, then it will be time to test fit and see if it all clears with the stock pan and stock k-member.

Jose

 

fuggin thread hijackers lol