A nitrous 318

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Dragonbat13

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MY build is a standard ole 318 magnum build. Eq heads, weiand action plus, carter 625, under 230 at .050 hyd roller. BUT, I have a forged crank and some scat I beam rods. But all the stuff that would make a good strong street 318. Nothing crazy.

I am thinking about building a "stocker with intake and headers" looking engine, but with a shot of nitrous that will probably max out at around 250 for the spray. Figuring 300 on the motor (on a good day). Cam will be a custom cam, stamped summit roller rockers, and conversion studs to run chebby rockers on some EQ heads.

Planing on using ICON forged pistons, in a standard or slightly bored (.030 over, preferably .020 over), whatever it takes to clean it up if necessary and keep as much meat as possible.

Also want to use head studs and possibly main studs. Quality head gaskets, cometic most likely.

Anyway, What I am wondering about is the widened ring gap. If I am spraying those larger amounts I am under the impression that the ring gaps would be widened quite a bit. When you get to the midrange 150 to 250 nitrous power levels do the ring gaps get wider, causing street reliability or street aggrivation. Things like excessive blowby, fouled plugs. OF course I know that it will happen, just wanting to know how bad. I dont mind doing a little extra maintenance over the norm. Swapping plugs every other month is ok. Swapping plugs everytime I drive it ten miles wont do.

I always wanted to spray a motor, and right now I am in a pretty good position with the parts I have already to build a nitrous 318 that everybody always talks about but never does.

As far as a 360. I just dont want to go that route. I got another motor for the big displacement fun, really want to try a 318 challenge.
 
I met a guy at the track last weekend with a 70 dart it was running 11.80s with a 318...360 ported heads 2.020 / 1.600 .....eddy rpm intake 750 Holley carb 1 5/8 headers 240/[email protected] cam .510 lift... compression 10 to 1 904 trans with low 1st gear 9'converter 4000 stall 5.13 gears 30'x9'slick .....it was a car built with parts he collected over the years nothing special really. Makes me think....... how quick would this car be with a 150 shot ..10s ?????
 
When I called nitrous express for my system they said "any production v8 can handle 150hp" They gave some recommendations for a base tune I.e timing to pull and sparkplug ranges and plug gap. He emphasized those were base line, conservative recommendations. He also recommended running their s.a.f.e. fuel system with race gas in it. He said this would allow me not be as conservative with the plugs and timing.

For my setup he told me 250hp was the limit for my setup.
 
I would suggest an adjustable kit and starting out at a 100 shot and working your way up.That way you can work on handling the extra power and learning the tuning curve.

By all means spray that 318 till it begs to out run big blocks.
 
I would personally upgrade to some good H beam rods too.......JMHO
 
Hot Rod or Car Craft mag back in the day sprayed a 318 they found in a junk yard .... If i remember right they sprayed 100/150/200/and 250hp with out blowing it up but at 250hp the ignition didn't like it ....started breaking up. They thought if they had a better ignition box ( msd) the junk yard dog would not have kicked up a stink.
 
The ring package and resulting gap depends on the piston material, piston design, and ring material. ICON has a couple different designs of pistons. The material should be strong enough in either case but the ring gaps may vary. Consult the manufacturers of the pistons and rings. I tend to keep the top gap bigger for nitrous use, and make sure the 2nd ring gap is larger too (it should be anyway).
 
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