Nitrous Pistons

[PurpleBeeper]

I'm running a relatively mild 440 with forged TRW pistons & a 125hp shot of nitrous. I've installed a cheater system (250hp shot) & I'm planning to build another motor. Do I need a "special piston" for a 250hp shot? I'm thinking I can just use any forged piston, but I want to see what you guys think.

 

[1967coronet440]

I'm running a relatively mild 440 with forged TRW pistons & a 125hp shot of nitrous. I've installed a cheater system (250hp shot) & I'm planning to build another motor. Do I need a "special piston" for a 250hp shot? I'm thinking I can just use any forged piston, but I want to see what you guys think.

As long as it's forged it should be fine

 

[dieseldazzle]

I've sprayed 215 horse on cast pistons. Good fuel and tune tho

 

[dieseldazzle]

I did open the ring gap tho

 

[Mike Gaines]

Watch out for TOTAL HORSEPOWER...over 750 or so and u will be testing your 2 bolt Main block

 

[lewtot184]

i've always felt like heat (too lean) and making maximum cylinder pressure too early in the power cycle would be one's greatest enemy.

 

[PurpleBeeper]

i've always felt like heat (too lean) and making maximum cylinder pressure too early in the power cycle would be one's greatest enemy.

Lean is certainly bad. I've seen a sbc forged piston with a hole the size of a silver dollar right over the pin from running lean.

Nitrous definitely produces a lot of heat, even with a good tune. I typically see about a 30F increase in coolant temperature in a 1/4 mile on the spray. In my mind (right or wrong), I've always thought that forged pistons were needed to handle the heat & the extra force.

Here and there I've seen references to "nitrous pistons", but I have no idea at what nitrous level they become "necessary" since I've only run 125hp/150hp shots so far. On Moparts, a couple guys mentioned something about finding pistons with the top ring lower and using special rings.

I think I'm just a little scared of hurting the motor with a 250hp shot and I'm trying to maximize my chances of the engine living a long time. I'm almost done adding a 2nd fuel pump/fuel line to supply the nitrous. I may not really need it, but I want to be SURE I have enough fuel supply. I melted a motor on another car running nitrous because the fuel pump couldn't keep up with the engine at WOT + the nitrous and I ran lean at the top end. I've also installed a multi-step MSD retard system for the ignition, but haven't wired it in yet. I want to pull out 3-5 degrees of timing on the bottle.

 

[69 GTX]

If the rings are lower on the piston you help avoid lifting the top piston land. You may also need just a little more piston to cyl. clearance. Also a programmable nitrous controller may help instead of dumping it all in at once.

 

[Challenger340]

4032 Forged alloys are for "small" amounts of Nitrous.... that's what your old TRW's are.

If you are going higher Nitrous ? or building a "Nitrous" Engine from scratch 2618 Alloy Forgings are a must.

 

[PurpleBeeper]

4032 Forged alloys are for "small" amounts of Nitrous.... that's what your old TRW's are.

If you are going higher Nitrous ? or building a "Nitrous" Engine from scratch 2618 Alloy Forgings are a must.

A little of both. I want to spray the current motor (again) & I'm starting to think about the next motor. I'm thinking about staying in the 125-150hp shot range on the current motor. Hopefully I can resist swapping out the pills until I put something stronger together.

 

[PurpleBeeper]

Watch out for TOTAL HORSEPOWER...over 750 or so and u will be testing your 2 bolt Main block

Hey Mike.....I'm right at that 750hp mark. What would be the next step if I want to make, say 850hp or so? Would I just need one of those side-bolted girdles on the mains? Aftermarket block?

 

[dieseldazzle]

Hey Mike.....I'm right at that 750hp mark. What would be the next step if I want to make, say 850hp or so? Would I just need one of those side-bolted girdles on the mains? Aftermarket block?

If you are making 750 on motor with a stock block rb I wouldn't spray it. I'd get an aftermarket block

 

[HEMI-ITIS]

With boost or squeeze,the ring pack must be lowered in the piston.