nitrous oxide

[BadBrian]

I need to know what kind of pistons I should use for a 100 hp nitrous oxide system do I need high or low compression pistons??? What are some good brand names Thanks Brian

[Trev]

From my experience, 100 hp doesnt require anything speical
Stock pistons and a stock engine will be ok
As long as its in good condition
Only need to worry about special stuff like JE or CP whne you go above 150 hp
Compression ratio stays the same
Trev

[Darin Morgan]

From my experience, 100 hp doesnt require anything speical
Stock pistons and a stock engine will be ok
As long as its in good condition
Only need to worry about special stuff like JE or CP whne you go above 150 hp
Compression ratio stays the same
Trev

Dito.

I have customers install 100HP plates on our Super Series engines all the time. They rarely ever hurt them. If you run at a high altitude you can put more to it. I have some customers in Denver that put 250hp foggers on our standard engines and they run fine with no problems. If you plan on going to 150+hp shot at sea level, you need to get some Nitrous pistons with the top ring down .350 and some Hell Fire rings plus lower the compression. Above 200HP shot you need the piston, rings and a cam with more duration on the exhaust side to get rid of the heat and lower the compression even more. That's a big mistake a lot of people make with Nitrous. Our standard 622 camshaft is a 286/306 @ .050 our Nitrous camshaft ( 450hp shot ) is 288/314 @ .050. If you don't get rid of the heat ( blow down the cylinder earlier with more duration) you burn pistons. You need to call and talk to someone who is familiar with the timing requirements and component selection needed to run various amounts of Nitrous Oxide. It will save you a bunch of money and burned up engine parts. Its very easy to get greedy with the stuff. A little is good so a lot is even better. Its human nature to think like that but you will be sorry if you go down that path without a knowledgeable individual helping you.

[Trev]

Darren
You lower the compression ratio when using above 200 levels
Do you do this when u have a strip only type engine with all the correct bits plus running C16

I am running CP Pistons built for nitrous with a really big cam and 13.5:1
would you see any benefit lowering the C/R


Trev

[ClassKing]

Darrin:
Do you see pistons from the greedy guys that have lifted the top ring land like a can opener? I was working with a customer that I found out later was not telling me the truth, (putting it the nice way,) and was using more NOS than I had reccomended - so, for a while it made it difficult to figure out why the top lands were splitting and peeling upwards.
When we first went racing together and I knew how much NOS was being used the engine ran great - never had these problems.

I had a vacuum pump that was only pulling 5 inches. Cam: Seat duration at .020 the cam was 278/290 on a 114+6. 451 inch 4" stroke engine. Ran 8.30's at 160+ in a 2700 lb car with a 250 shot. I've since wondered what exactly caused this. Thanks for any tips.
Best Regards,
Bruce

[ClassKing]

Anyone have thoughts on the previous question?

[shawn]

With nitrous there is varying opinions on what causes what to happen. Kind of the chicken or the egg theory. My opinion (for what it's worth) is that a lifted ring land is usually caused by the ring end gaps butting and acting like a lever pushing up the edge of the piston. This comes from excess heat, not enough ring end gap, or (this will usually cause controversy) to much retard in the timing.I usually don't put as much advance in the cam as what you had listed and it seems to help this, too.Hope this is the answer your looking for?
shawn

[bill jones]

-Where were the ring lands lifted? in the same place each time? near the exhaust valve relief? near the intake relief? how about explaining or show a photo of the damage?
-Where was the top ring end gap in relation to this lifted ring section?
-What engine are you concerned about?
-what fuel (brand and designation) were you using?
-What was the lowest rpm you used the nitrous?
-What was the sparkplug gap? heat range? what ignition system? how much compression ratio?

[ClassKing]

Before I rely on my memory of the damage location I'll get a picture of the piston tomorrow - and can someone clue me in on how to post it? I'm a medium computer operator.
#1 - I'll be lucky to have a piston that has the rings on it - and even if there are rings still there I don't know if they've moved.
#2 - Traditional Pontiac
#3- Race gas 114 Type varied - whatever the track had on hand.
#4 - I tried to get the owner to use a tighter converter - and going by what he told me, (later proven unreliable,) it was locking up around 3500.

#5A - Champion C59YC , .030 gap, MSD digital 7, 13:5.1 Cr.
timing 22 to 24 degrees.

Again - the times I went out with the car it ran with no problems.
When the owner played crew chief he lifted ring lands three times.
I later found out the last time the car ran at the end of the year, he had changed the cam - although he didn't hurt the engine that day, he was a full two tenths slower. I found out he had installed a much larger duration cam. I also found out he had upped the shot a bunch.

On current successful nitrous combinations I'm like Shawn - I run less nitrous and don't retard the timing as much as some folks seem to.
The Pontiac 9.5 Cr. 350 I built that was in Car Craft made 539 hp on the engine, and on a 125 shot it made 672 hp, and I ran the engine like that the rest of the year. 38 degrees locked out. No retarding at all. Of course that's not apples to apples to this other combo.

[Trev]

They wernt KB Pistons where they
They require much larger ring end gaps and if not given will do that, as i look in the waste bin and stare at a set lol

[ClassKing]

? no, no...
Custom JE made for the job with a .300 or .350 top land. Can't remember exactly right now. Past midnight now - Time to hit the rack ZZZzzzzzzzzzzz.......

[bill jones]

-what type of chambers did this Pontiac have? were they the concave type in the shrouds or were they layed back and into an open style chamber.
-Those concave chambers are terrible bad with swirl at high lift particularly over about .400" lift.
-How much honest lift at the valve did this engine have?
--------------------------------------------
-I'm particularly interested in if the ring land destruction appears to have started close to the intake valve notch area and whether or not the top ring end gap was in that same area.

[Guest]

I'm still recovering from a car accident - and I think I got whacked in the head too hard...

After seeing the piston today - I had it confused with a previous combination - but only the compression is different - it's a JE flat top and it's burned at the thin spots where the valve pocket comes to the o.d..
Both pocket edges are lifted. Cam after lash was .525 lift.

It was a modified Edelbrock head.

[bill jones]

-One thing that racers need to get serious about is understanding what happens when you have wet fuel entering the chamber, and how it causes the ring lands to lift.
-Fuel HAS to evaporate to do it's work, and liquid fuel is detonation waiting to happen.
-The fuel washes the top of the piston and gets in the "crevices" and stays liquid until the heat from compression vaporizes it and sets that crevice fuel off.
-This is one reason that I religiously install the top ring 180 degrees from the intake valve notch.
-------------------------------------
-All fuels have what is called an evaporation or distallation curve, that shows the temperature necessary to vaporize the various stages of the fuel.
-You NEED to get that info and be looking at it, and quite possible making a fuel change, for any nitrous or blown or restricted inlet application.
------------------------------------------
-I've seen the ring lifting problem fixed by roughing up the port walls and the intake half of the chamber-especially the shroud and the top of the piston, with stones, and then the fine grooves that encircle the top ring land also help and the sharp demarcations of the intake valve and the intake seat all work to break this fuel up.
-I would even go so far as to swirl polish steel intake valves with a very coarse sanding band.
------------------------------------------
-The nitrous is so cold that it freezes the fuel so you have to have an extremely low 90% and end point numbers on the evaporation curve and you have to induce some heat into the fuel (the wet fuel touching the coarse port walls helps here).
-Then if you apply the nitrous at a low rpm there isn't any help from airspeed to keep everything mixed good.

[ClassKing]

Interesting information. Thanks.