Hey guys....i have some questions too...
I have a 86 t-a,with a 78 gmc truck 350 4-bolt in it...i plan on taking the motor out to rebuild it anyway. I have new summit polished rods,steel roller rockers, torker2intake, 600 holley(should i get bigger like a 700 or 750?) sitting on the bench already,etc..i was planning on running some type of forged pistons...
What type of piston(flat-top,domed,wedge), compression ratio,valve size, cam is needed to run well with n2o? I saw a line of cams from comp cams made for n2o(nitrous hp)...id pick pretty lumpy(2500-6500 rpm) with duration 274 intake 292 exhaust, as this is going to be a weekend rice-eater car not a daily driver. Id like to use NOS brand cheater kit for holley 4-bbl which i could adjust from 150-250 hp. I think on the limited budget i have,n2o is the way to go!!!
im a little lacking on funds(the reason why i dont own a supercharger lol) Am i thinking right? i dont know a whole lot about engine building,i mean i can rebuild or install anything,electrical and s.e.s. light type stuff is my forte at work.I just dont know a whole lot about cam degreeing,factoring compression ratios.etc...
somebody please let me know if im thinking right with this whole setup..mike :lala:

 

COME ON GUYS!!!!!
anybody else running a setup like the one im planning on?see any major flaws?????

 

forged pistons are a must for any motor to me.....

the more compression the better.... but theres if and buts in there as well..

nitrous works as a power or pressure increase...... or it pushes the piston down with greater force which is hp.......

the reason it pushes the piston down harder is because n2o increses cylinder pressure, as higher compression does.........

the down side is knock and pre ignition and durability if certian things are not in place......

if i were you, i would decide wether the motor will defanantly have n20, how much n2o, and what rpm's are expected....

thats what ya need to do, build the short block with the good stuff that way whatever you decide you will know if the motor can handle it....

call comp and see what they reccomend as far as durations and lift goes....

 

?!?

 

thats wrong dude!!!!

 

i tried searching....i hate getting told to search for krap, i cant find it.Id rather ask people and get real feedback now not from 2 years ago lol. I DO PLAN THIS TO BE A N20 motor!! its not going to be a daily driver,so im plannign that hotp cam.It would be nice if it still runs half ok off the laughing gas too,but i do plan on having a baby bottle back in the hatch lol .Im planning on a n2o kit adjustable from 150-250 hp.....i planned on running some type of a forged piston. i asked what compression would be decent to use with this setup. that then would factor what typs of pistion i would use.I have a nice set of eagle rods(steel) from summit with arp bolts,all polished and pretty....would those hold up? If the heads turn out to have 2.02" intakes,i plan on rebuilding and using them unless im told otherwise. If the intake valves are smaller(1.94"),could i still use those and make decent power,or would you all suggest a new set of heads? I plan on using the cam above,that makes power from 2xxx-6500 rpm. Its made by comp cams,especially for guys that run a 150-250 shot ot n2o. Of course i plan on puttin g a high stall torque converter in. id be runnning(unless im told otherwise) a edelbrock torker2 open intake.Im assuming id need a bigger carb then the new zinc plated 600 holley i have now.(anybody want a nice carb for thier stock 305 or 350?lol)
I quess i need to ask:"What n2o setup/motor parts are you running?"
im sure i can tackle this,i just want to make sure im thinking right before i go buy stuf that wont work well togther

 

oh I forgot....id hopefully using my stock crank unless a 150 shot of n2o will kill it,in which case i guess id have to break down and but a nice steel crank...pretty sure this one is a 4 bolt too

 

Oh and b4ctom...that pic should have a exclamation point on it at the end of the text(!)
not a question mark(?)..............................................
Thanks for the help though....dr. evil pics and posts with smart a$$ comments really help me figure out my motor and n2o setup......mabye a comedy break will let all this setup info just magically plop into my brain....yeah thats it...
This is why i quit using thirdgen awhile back....you try talking to and asking questions to other car-nuts(especially thirdgenners)and all you get it stupid a$$ comments and b.s. picturesthanks a ton for the superduper excellent help from you!

does anybody here actually want to help another fellow thirdgenner or what???????
if you really want to help,you are the man :hail: :hail: :hail:

 

forged are a must!!!!!! try for about 9:1 compression so that 200 shot wont kill the pistons.......

those rods should be good for i'd say 500hp, on a every now and again motor........ not strictly race only.....

also try to get a big hyd roller cam with a wide lsa for the n20........

 

thanks! anybody else want to actually help like badgta?
thanks dude!!

 

oh yeah..i can get trw forged pistons cheap...they anyt good?theyve worked great on my all natural motors but ive never used em with any big compression or power adder type of stuff...
any special type of pistion rings i should use?

 

EVERYTHING YOU EVER WANTED TO KNOW ABOUT BUILDING A NITROUS MOTOR BUT WER TOO LAZY TO LOOK FOR ONJ YOUR OWN

 

you'll have to excuse mr. tom. He has no tolerance for.. er... weel not go thar.

Im going to add a few "tips" although I do not consider myself the resident nitrous expert, I think i can add a few items to think about.

cylinder pressure VS exhaust duration. Remember N20 jacks up CYlinder pressure to make its insane power. with increased cylinder pressure, obviouselly, you have alot more IN the cylinder, Thus you have alot more to GET OUT of the cylinder. Typically, an exhaust duration of about 10-20* MORE than the intake works well, according to comp. Some really high Nitrous HP cams even have as much as 25-35* extra exhaust duration. But thats for like pro-stockers or whatever...

but, obviouselly, when you add exhaust duration, you move the END of the exhaust valve cycle even CLOSER to the beginning of the INTAKE valve cycle, which means a LATER Intake valve openening and thus less time to fill the cylinder without going to insane ABDC intake valve open times thus giving you a really "lumpy high rpm camshaft" due to excessive ABDC intake valve opening.

The bottom line to all this mumbo jumbo is you cant have a TON of duration and a SUPER lumpy cam and expect nitrous to do very well. Yeah, sure, it could work, but you explained your on a BUDGET and this kind of cam deal requires a set of MATCHED UP PARTS to work well.
Example:
a camshaft with 290* of duration and a 114 LCA (for N20*)
Powerband: 2800-6200 RPMS
Why so narrow? Due to the high duration (290) and the WIDE LCA (114) you have an intake valve closing WAY after BDC, which means to generate USEABLE power you need to have the engine moving at LEAST 3,000 Rpms. and even then, your just barelly in your power band.
So, with this power band, we need a nice set of MATCHED components. A matched high-RPM component is going to need to promote power in that range.
Examples of High-RPM components:
4.11 Rear Gearing
2.05/1.60 Fully ported Aluminum Heads 190CC or bigger
Single plan Intake manifold
Tranmission that wont drop you out of your RPM band on the 1-2 shift (aka "no 700R4's here please")
High Stall converter
As light a car as possible
now lets add N20 To this Buildup:
Torque Converter with Anti-balloning plate
Tranny that wont explode when you hit the button
Rear end that " " " " " "
Forged Crank, Rods, Pistons, depending on how long you plan on keeping the engine.

I can go on forever, But the point is, when you look at lumpy cams, you need everything to match. you cant take a slightly modified engine and throw a lumpy cam in it.
Typical mistake/misuse of lumpy cam is where the ENGINE is properly built for HIGH RPM (cam, headers, Heads etc..) but the REST of the DRIVETRAIN doesnt match! You can expect your 2400 Stall and 2.73 Gearing to complement your 6500 RPM engine!
and THAT EQUIPMENT gets EXPENSIVE.

Thus: The moral of this story:
We dont need a lumpy cam to make useable power, especially with N20 and especially when on a budget.
My opinion: use a decent 2000-5500 Cam, 110/112 LCA (NOT a NITROUS HP CAM) and a decent drivetrain (2200-2400 Stall, 3.73 Gearing) and decent internals (forged pistons/crank... Decent rods) and decent heads (1.94 or 2.02. whatever... get them ported maybe... Aluminum helps with heat Xfer so look into that for sure) and then you have a decent setup, mid to high 12's without the N20, then throw the juice on when you want and hit the 11's safelly.
thats my onion(opinion)

 

i'm running trw or their brand called speedpro l2491f-30 for my 383 stoker and they are good pistons!!!!!

be warned, they wont take over a 150hp shot of n20, if ya want more try je or srp racing pistons.............

you can also get a set of scat h beam rods for under 400 and they will hold up to like 700hp......

 

sweet this is just what i was asking...thanks badgta and king!!!
i guess the best thing to do woul dbe to call comp and say hey,ive got this and that,these heads...i want to run a 150-200 shot of nos occasionally what is the best cam?

see ?i didnt know what cam etc to run...thanks again!!!
anything else the nos beginner should know???

 

yeah spend the extra $$ on the purge valve and fuel safety switch. your engine will thank you later.

 

sweetness....anybody else want to help a n2o beginner...
and even though all my tools and caddie got broken into i will still keep working when i get tools....
later!
:rockon:

 

I disagree on using TRW forged pistons on more than 150 shot. I've been using those pistons (L2256F30) on my car for over 2 years. I have not had any problems shooting 200 shot. As long as you dont lean out the engine, run proper timing. and high octane fuel, you shouldnt have any problems with TRW. Also dont forget to use the correct plugs, something a lot of people overlook.

 

<b>you shouldnt have any problems with TRW</b>
my opinion also. Very reputable piston/rod/bearing/crank/etc... manufacturer. (Aka Federal Mogul). Same company I beleive.

 

yes ive heared of switching plugs....how much colder? anybody have a brand and-or p/n to reccomend?
tho spistions...are those the ones with the valve reliefs,or flat-top?
thanks dude!
p.s. think the stock crank will hold a 150-200 shot???

 

unless you buy a JE with custom ring placement the TRW is stronger. here is a pic of a TRW that was sprayed all season with around 300 hp and once at like 250-300 without fuel or almost NO fuel for the pass on a 9 second run. We didnt even know there was a problem until the end of season tear down.

 

As far as plug recomendation, I would need to know what heads, compression, and how much NOS you plan to use. Whatever you do, dont use platinum, or any other "gimmick plug". I work at an auto parts store, and sell a ton of plugs for nitrous applications.

 

damn tom,yeah id say you had a hell of a load on those rings (btw...do you buy 0 gap rings and file them yourself ,or do you buy "regular" ones?)
Do you run regular or moly rings with nos? im planning on starting with a 125 or 150 (wet)shot to get used to the nos system and fix any obious traction or driveline probs i might have.,but you know me ill jack it up to 200(wet) a few runs after.
Good im glad to hear that trw makes good stuff,because thats the line of pistions and stuff my dad sells...if i want to keep the stock heads and stroke(5.7"),should i use the flat-top pistons trw makes or the ones with the little valve reliefs in them? i havent been able to cc the heads yet but they should be whatever cc came stock in the late 70's pickups..with the stock heads and the stock pistons with valve relifs,i (believe) the compression is about 9:1 or 8+1/2:1
thanks again for your input,and sorry for giving you earlier..
i just got pissed cuz i needed info form folks that know what thier talking about,and now im getting it(whoohoo)
laters...anybody else want to put in thier $.02??????

 

A real easy pump gas motor to build...

Use the TRW forged flat-tops... pn L2256 (they take incredible abuse)
Use the Comp Cams 305H magnum cam (hydraulic)
Any rods (stock w/ARP bolts is fine)
Any crank (yes, even cast)
Stud the mains, and align-hone the block(with NOS, caps tend to move around)
Use a decent set of 2.02/1.60 heads with 76cc chambers (to keep CR down at pumpgas level) OR do a nice pocket port job on your existing heads...
Use a head stud kit (holds head gaskets better for NOS)
Ditch the torker2 intake, the corner cylinders will go lean on the juice (not enough plenum height/area for NOS)
A Holley strip dominator intake is cheap and effective...
Use a Holley 750 DP carb
Use the NOS Bigshot system, and start off with the small jetting...
Run a seperate dedicated Holley blue pump, and 1/2" fuel line for the NOS system...
Be ABSOLUTELY sure to use a cheap Holley regulator...(seen too many meltdown w/expensive BG regs)
Set fuel pressure at 5-1/2 lbs "flowing" through the jet...
Bottle pressure works best around 950psi...
MSD 6AL ignition and a retard box is a MUST...
Retard about 10 degrees when juice activates...
Run colder sparkplugs (AC delco R42's work great)



This is a "safe" setup...
You will get max HP from the NOS without a meltdown...


In a 3400lb car with the right driveline(3500 converter/4.11 gears) behind this easy to build pumpgas motor, you should EASILY see low 13sec 1/4 mile times WITHOUT the juice, and low 11 sec times on it... Faster if you know how to tune it...

 

high compression and alot of juice. After going to a performance engine buiders seminar in colorado where I got to listen to a bunch of industry and race engine builders give presentation, we were convinced that total seal rings are the absolute best rings there are...FOR NORMAL ASPERATED ONLY. The consessus that I got was that a dangerous pressure CAN build between the rings that can lock them in the bore and rip the top of the piston off or snap the rod. Before everyone flames me for posting this because they "used em for years in their blown/nitroused/supercharged engine with no problems". We took them at their expert opinions and just used gapped rings in that motor and you can see if you look closely in that photo that even with a "larger hyperutectic style gap" on these forged pistons we still experienced a mild form of the phenomenon (thick top ring land pushed slightly up, lower ring land pushed down). I almost exclusive ly use plain cast on nitrous motors (no moly filling to block heat transfer to the bore) and moly on just about everything else.

 

that's actually really interesting, does that include gapless rings that only replace one of the rings or all of them? What about boosted/turbo applications?

 

I would guess all

 

Buddy of mine was running a blown alcohol SBC, and had to open up the ring end gaps to .030+ to keep from lifting the ring lands...

I was running NOS for 10+ years with 14.5-1 pistons, and never had problems with rings...

I always used a decent set of std gap file-fits...
Moly top, cast 2nd, low tesion oil...

This setup withstood 1200+ HP for a whole season at a time...

I have had a meltdown or two, but they were unrelated to pistons or rings...
Usually plate, or solenoid related...
In those cases, it didn't matter WHAT rings you ran, the NOS burned right through 'em like a torch...

 

sweet! its nice to get some feedback...i plan on pocket porting and gasket matching the heads,an hv oil pump,keep the crank,use my summit eagle rods,and a new set of trw flat top pistions(with no valve reliefs)..also a 750 holley should work ok...the torker2 wil have to do for now,howeve ri will jet the gas a few steps up to comp fo rthe corner cylinders leaning out untill i can get a holley intake thats prefect for nos. who else is running what???? what nos setup do yo uhave???? let us know lol
:rockon:

 

well im still battling with my insurance over getting paid for all my tools that got stolen from my gagage....might as well start selling stuf i cany use while im waiting for insurance B.S. to be over with......anybody want to buy a very affordable torker2 intake or 600 cfm silver plated(powdercoat?) holley?????