lt1 nitrous pistons and compression ratio - NJFBOA - Home of New Jersey's Camaros and Firebirds

sweetbmxrider · 11-13-2009, 10:59 AM

Just looking for some good info on quality pistons that can take a 2-300 shot no problem. they would be for a .030 bore with a 3.75" stroke crank, not certain on rod length. Looking currently at Callies Compstar crank and rod packages.

Also, what is a desirable compression ratio for that much nitrous on an lt1? stock is 10.4-10.5:1 and i see many builds up around 11.5:1. would like to retain street manners and 93 octane. Head cc is 54 and it seems pretty tough to get the compression in the 11.0:1 range with flat tops. should i just run a cam with more overlap to bleed off some compression?

thanks for any and all info

LTb1ow · 11-13-2009, 11:05 AM

How big have you gone with the head gasket? Prob not the best to have a larger head gasket on a larger shot though..

What are you looking to spend on pistons?

sweetbmxrider · 11-13-2009, 12:38 PM

i was computing with .040 since the block will be zero decked but am open to opinions as always.

under a grand

11-13-2009, 12:38 PM

Nitrous likes higher compression

sweetbmxrider · 11-13-2009, 12:40 PM

but with a larger shot you can run into detonation issues, no?

11-13-2009, 12:42 PM

ask bill, he runs a 300

sweetbmxrider · 11-13-2009, 12:43 PM

yeah haha been meaning to talk to him and his mechanic

LTb1ow · 11-13-2009, 12:43 PM

Quote:

Originally Posted by sweetbmxrider

but with a larger shot you can run into detonation issues, no?

You could run a fuel cell with 110 or higher in it for your nitrous.

And you are stuck with zero decking it or is that what you want to do?

sweetbmxrider · 11-13-2009, 12:53 PM

Quote:

Originally Posted by LTs1ow

You could run a fuel cell with 110 or higher in it for your nitrous.

And you are stuck with zero decking it or is that what you want to do?

very true and the block will need to be inspected first but i am most certain it was zero decked in its previous life.

LTb1ow · 11-13-2009, 12:55 PM

Custom pistons.

Or try to bleed some CR off with cam, but thats all complicated and what not. Who did you plan on getting a cam from? Off shelf?

sweetbmxrider · 11-13-2009, 01:01 PM

le speced

this isn't amateur hour, is it?

so who would you recommend piston wise?

LTb1ow · 11-13-2009, 01:12 PM

JE/Diamond/Wiseco (sp?)

TRW maybe, be cool like me, and rock speed pros?

S.J.SLEEPER · 11-13-2009, 01:15 PM

nitrous likes compression, its all about the fuel/octane & supply. along with where the ringlands are located @ & there gap.

the larger the shot the lower the rings should sit on the piston to reduce the chance of meltin along with the ring gap needs to be larger.

i ran 12:1 compresion 383 stroker with ringlands set at 450thnds down and gap set @ 28-30thnds.
pushed a 350hp shot via direct port inj.

also you don't want the nos to come on til about 3600-4000rpms
otherwise you could rattle the motor

S.J.SLEEPER · 11-13-2009, 01:16 PM

oh.... also ran a seperate fuel cell & pump w/116octane for the fuel side of the nitrous

WildBillyT · 11-13-2009, 01:40 PM

Quote:

Originally Posted by LTs1ow

JE/Diamond/Wiseco (sp?)

TRW maybe, be cool like me, and rock speed pros?

TRW's are heavy. JE, Diamond, Venolia (heh).

Stupercharged · 11-13-2009, 01:55 PM

I vote JE's they're a little pricey but you get what you pay for, I had diamonds in my little grandprix and I was running a hair lean and the baster** shrunk on me

sweetbmxrider · 11-13-2009, 02:55 PM

yeah i was looking at the JE's, they seem quite nice.

Quote:

Originally Posted by S.J.SLEEPER

nitrous likes compression, its all about the fuel/octane & supply. along with where the ringlands are located @ & there gap.

the larger the shot the lower the rings should sit on the piston to reduce the chance of meltin along with the ring gap needs to be larger.

i ran 12:1 compresion 383 stroker with ringlands set at 450thnds down and gap set @ 28-30thnds.
pushed a 350hp shot via direct port inj.

also you don't want the nos to come on til about 3600-4000rpms
otherwise you could rattle the motor

i have a window switch for the last part. was kinda thinking about a standalone, but at the same time it seems like it could be a little excessive. if i go direct port then yes. if i don't and only do a nitro dave's plate which is what i'm really leaning towards, then i would want to stay with a line from the fuel rail.

LTb1ow · 11-13-2009, 03:09 PM

Pulling fuel for a 200 shot off the stock rail and lines may be risky man.

Relocate your battery and run a N20 outlet fuel cell up there. Very nice stuff.

sweetbmxrider · 11-13-2009, 03:44 PM

yeah it does look good. you're killing me though

LTb1ow · 11-13-2009, 03:47 PM

http://www.yellowbullet.com/forum/sh...d.php?t=181436

Granted a lot of those motors are strict race motors but some of those guys are running pretty tall head gaskets and large nitrous shots. That thread though is for aluminum rods and I assume making sure the stretch they experience won't cause PTV issues.

Also, not sure on ring gap for nitrous being good for DD dutys...

O ring your block.

sweetbmxrider · 11-13-2009, 04:02 PM

yeah its not really going to be dded, just takin out on nice days and meets. thanks for the link though.

LTb1ow · 11-13-2009, 04:04 PM

Have you talked to Lloyd yet about your cam?

I would get that figured out, kinda important and linked to your piston choice and what not.

And you should run Jesels.

1984camaroz28 · 11-13-2009, 08:35 PM

11.5 to 1

Pulling Fuel off the rail on a large shot is a time bomb

U can run a Stand alone for ur n2o and run some c16 in it. Pump Gas is going to really limit the power potential

transmaro93 · 11-13-2009, 09:12 PM

haha 300shot??? your crazy dude.... this car should never see the streets... i wouldnt sacrifice compression by fudging with the cam specs... seems kind of redundant to me and you wouldn't be using the motors full potential.... 53cc is a little tight with a flat top... my heads are 63cc chambers and my CR is like 11.0:1 not sure what gastket they used... but probably what ever standard is... my block is zero decked also... its not a daily so if you have to run race fuel in it or a mix so what... its not like your filling it up every 4 days...did you ever look into those coated mahle pistons...they are pretty affordable and are supposed to work really well with nitrous... you are going to have to do some major fuel upgrade too man.. i dont know much about the nitro stuff but i know that the little 255 through the stock lines probably isnt going to be enough to fuel that motor plus a 300 shot... i cant wait to see your build sheet when your done to compare it to mine... becuase iv spent god awful loads of money so far... and your goin the distance ahah... just a forwarning... it sucks when you spend a ****load of money like i have right now and its not even running... so dont get discouraged from that... and i have a o2 sensor extention if you need it... i didnt end up needing the one i had... ill prob have other crap too left over that you maybe can use... but nothing you will need anytime soon...... **** THIS WEATHER I WANT TO START MY CAR!!!!!!!!!!!!!!!!!!!!!!!!!! well talk more toamarrrow night at the meet..

S.J.SLEEPER · 11-13-2009, 10:40 PM

if you plan on going w/ a 300 shot. you better plan on gettin a nitrous controller while your at it, along w/ seperate cell,pump, etc... like me and 1984camaroz28 said above

probe & mahle pistons are pretty nice and aren't too expensive.