Thread: Cam gear settings with nitrous?

There may have been but that was a long time ago and I don't remember lol.

first off it good to degree your cams and i all so find in chevys that a nitrous cam works its best at high nitrous levels. and some times with low nitrous levels a na cam will make more power on nitrous.

Aaronx heres some tips about assembling or building a engine for nitrous oxide (nitrous motor)i will most of the time use all forgded internals. pistons with bigger first ring lands are are good to keep the first ring away from heat and should be stronger.One of the most important things in my opinion is ring end gap make sure u gap your rings properly for nitrous oxide.Because of the added heat from nitrous u should have more gap to prevent rings from butting.nitrous to 150 hp bore x .006 in nitrous hp over 150 bore x .008 but u should always refer to piston and ring manufacturer's specific recommendations to prevent ring end butting.as far as heads go there are none made for nitrous motors that i know of. i work on the exhaust side more i usely go with a bigger exhaust valve and port the exhaust port.I do this to reduce pumping loses.i also increase the wrist pin clearance by .0005 to .001 in if useing medium to high levels of nitrous if this is not done the pin bores will scuff and this could lead to seizing.when nitrous is injected into the cylinder,it has the same effct as increasing the cylinder displacement and the intake valve size.as a result the exhaust valve becomes inadequate when this happens the pumping losses on the exhaust stroke escalate to substantial levels.even a system that produces 150 hp increase in a typical motor the pumping losses can amount to 100 hp in other words an 250 hp is being made in the cylinders on the power stroke but 100 is being re absorbed by the crank on the exhaust stroke.the most effective way to compensate for inadequate exhaust flow is a trade off in intake valve area for exhaust area.for a typical small block chevy this means increasing exhaust valve diameter to somr 1.8 in and reducing the intake to 1.85.but most of the time this cant be done.our only other option is to cut exhaust pumping losses by opening the exhaust valve earlier.in essence the intake events needs to occur at the same timing as it would with out the nitrous but additional exhaust opening needs to be tacked mostly onto the opening side of the exhaust.to see how this works in practice lets look at a example.if the cam of choice before the decision was to inject nitrous was a 270/270 cam on a 106 lca at 4 degrees advance (intake center line at 102)the valve events would be as fallows intake opens at 33 btdc intake closes at 57 abdc exhaust opens at 65 bbdc exhaust closes at 25 atdc abbreviated thats 33 57 65 25. to cut losses from the use of nitrous.lets assume we open the exhaust valve at 12 degrees sooner but all else needs to remain the same this now produces valve event timing of 33 57 77 25 because of the change we ve made in the exhaust our cam is now a 270/282 in terms of duration but revised ex opening has caused the lca to open to 109 degrees and if the intake center line is still at102 the cam is timed in 7 degrees advanced if relatvely heavy loads of nitrous will be used the ex may need to be opened as much as 20 degrees sooner thus making our example a 270 /290 cam on a 111 lca and intake 9 degrees adv what this means is any cam having a lobe center line angle 3 to 6 degrees wider than for reguler use having 10 more degrees on th ex can be used as nitrous cam if installed 6 to 9 degrees adv. this is for chevys but it should give u a idea on how to make more power with nitrous and make it safer of coutse there is a lot more to this but i am done typing and make sure the rite heat range plug is used also

WOW!!!

So I read Buicks post 3 times, extreamly informational, and technical. Im trying to sum this up so that I can fully understand it. Excluding the first part, your saying that in order to make big power with a nitrous only motor the exaust valves should be enlarged and the exaust side of the head should be ported and polished to help the scavaging of the exaust gases which will help eliminate pumping loss? Then you go ahead and explain how to find valve overlap?

any time u port heads know what your doing bigger is not always better definitely when porting heads its easy to over do it u need velocity. And of course more air flow on the intake side will help get more air and nitrous in the engine also. but its more important to work on the exhaust side with large amounts of nitrous. it pretty much makes it easier for the engine to push all the extra gases out of the cylinder. as far as exhaust scavenging effect deals more with pressure wave tuning but anything after the ex valve deals with or can help scavenging effect witch is kind of like vacuum caused by the pressure waves in your exhaust witch pretty much suck out the exhaust from the cylinder. exhaust scavenging deals manly with your exhaust tuning with nitrous you also need a better flowing exhaust but i dont feel like getting into pressure wave tuning today maybe tomorrow.also as i said in another post a finely tuned exhaust CAN cause a 500 % harder draw on the intake port than a piston going down the bore.

i forgot to add that buy reducing pumping losses on the ex stroke can also reduce friction losses on the ex stroke

That's a Mike K response right there.

who is mike k

Mike Kojima, used to work for Sport Compact Car magazine. Long time Nissan guru that REALLY knows his stuff.