How much nitrous can I safely run?

[BrentRS1985]

I have a 4 bolt main 350, stainless steel crank (I can't find any info on stainless cranks, but thats what the machine shop told me I had), 302 chevy (pink) rods and speed pro forged aluminum pistons. How much do you think my bottom end can handle? I don't have arp bolts but will once I put the no2 on it. Good rods aren't too expensive these days so I will probably get new ones just to be safe (any recomendations?). But I really can't afford a $1,000+ crank right now. I am hoping a cast stainless crank is better enough than a plain cast steel crank to handle at least a 150 shot if not a 200. Maybe you guys can tell me what I've got by looking at this picture...

as usual, any help is greatly appreciated!
oh btw, when I get home I think I have a few more pictures of the crank that are high def if they are needed

[Hottrucks]

wet system or dry???

if wet let it have it I would start with 150 do a run and shut it down to do a plug check for a lean condition then adjust accordingly....I run 150 on my V8 s10 and it's on dot slicks with an auto and its only a 2 bolt....but I have run as much as 225 on a hot day to keep me in the 12.99 bracket

[BrentRS1985]

Originally Posted by Hottrucks

wet system or dry???

if wet let it have it I would start with 150 do a run and shut it down to do a plug check for a lean condition then adjust accordingly....I run 150 on my V8 s10 and it's on dot slicks with an auto and its only a 2 bolt....but I have run as much as 225 on a hot day to keep me in the 12.99 bracket

I was going to run wet (actually I thougt you had to run a wet kit if you are over 100 shot and are carbed). Are you running a forged or cast crank? What rods? What are you spinning it to?
I'm probably worrying about nothing, I know a guy that has over 75 passes on a stock bottom end ls1 running a 300 shot. Although the ls1 is a 6 bolt main, its aluminum.

[Hottrucks]

stock cast
stock

the shift light comes on at 6800 but it has been held till the vavles flutter many many times and I don't look!!!

what the perpose of doing it ?/ are you racing or just using it for a teaser??? also how much HP are you making with out it??? going from 200 hp to 300 is one thing going from 350 to 500 is another

[swb85]

How much power N/A? What are your rings gapped to? I personally wouldn't spray more than 200 on a cast crank. Gap the rings right, run the right plugs and pull enough timing and you should be fine with 150-200.

[BrentRS1985]

Originally Posted by swb85

How much power N/A? What are your rings gapped to? I personally wouldn't spray more than 200 on a cast crank. Gap the rings right, run the right plugs and pull enough timing and you should be fine with 150-200.

I haven't had it on the dyno but I'm guessing around the 400 range at the crank. I'm honestly not sure what my rings are gapped to, can I find this out when I remove the heads (I want to find out how much valve clearance I have before choosing a nitrous cam). I'm wanting to race it, but it will be mostly street driven. I won't be on the bottle very often.

[Hottrucks]

thrn I would stick with a 150 shot and let it live!!!!!!!!!

[scatesracing]

safely might be the wrong word to use....LOL... I have hit mine with 200 countless times.... cast crank,hypereutectic pistons,two bolt main.... pull the timing and dont let it lean out.... Let her have it

[z400rider8787]

as long is you make sure you dont lean it out and you dont spray it for too long of a period at once you should be ok. another option you can look into is doing what i did, i just got a stock forged crank (1182 number) and use that. its almost as good as aftermarket forged and i picked it up for 100 bux had it turned for 100 and now i have a great crank for 200bux. im gonna spray mine with a 150 shot but ill have h beam rods and forged pistons on a 4 bolt. im not worried about the bottom at all, i'd spray it all day. but with a cast crank just be responsible with it and dont get too high in the RPM range while your spraying, because RPM's are hard on the bottom end and so is nitrous so combining the two is asking for trouble ona cast crank

[hotrod 80]

I'd start with 150 and use that to perfect the learning curve and break in the rings . I have run 210 on a similar combo .

[Marv D]

Everyone has a recipie,, I was dumping a 225 shot at a cast crank, stock rods and a set of good TRW forged (L2304f) LT1 clones. I burned through a couple hundred pounds of N2o and 7200 rpm shifts and the worst thing that happened was melted the tip off a couple of plugs. Follow the rules and you should be OK but it's ALWAYS a gamble.

Once you have a solid baseline for your motor unboosted, here is some very conservative guidelines

For every 50HP of N2o reduce timing 2 degrees

For every 100HP of n2o add 10 octane points to the fuel you run,,MOTOR OCTANE, not R+M/2 or anything else, research the MOTOR OCTANE of the fuel your using.

Increase fuel pressure 1.5 to 2psi for every 100HP of n2o.

Run 1 heat range colder plug for every 75HP you add with N2o.

Follow those general starting point guidelines and your motor should survive IF it is in good condition to start with.

I think I have a page with motor octane listed for many of the more popular brands of race fuel.... I'll see if I can't find it and edit a link in here.

[Marv D]

Oh,, bTW, "stainless steel crank" ???that's an interesting one!!! I don't think so. Someone ws mis-informed or misunderstood. Stainless is really not that strong, it just polishes up pretty and resists stains and rust AS LONG AS it isn't in direct contact with more ferric metals.

[Marv D]

Found it. Her's the fuel page in .pdf format

http://www.small-block-chevy.com/FUELS.pdf