slo406

So i have a totally forged bottem end on my 406..

eagle sir rods: 5.7
eagle crank: 400
JE aluminum pistons :4.155
+11.5 comp

How much juice can i safely throw at a high revving forged 406? (6900 RPM @ the end of the 1/4 )

id like to go with a 250 HP Shot ..But Def more if i can.

tilstad

I think the key when going big on nitrous is to keep a very close eye on the fuel delivery.

As far as I know, there isn't any real limit to how big you can go on an engine as long as the fuel delivery is up to it, and within the blocks limits.

As for a good 4 bolt 350 block, I have heard that it could take about 700 hp or so. Better be certain of this though.

Although this is the general rule of thumb, there is basic limits when it comes to the combo. If you run a measly 2 barrel carb on stock 305 manifolds and a small exhaust, the engine may have trouble digesting all of the nitrous if you go really big. It seems that you could safely go to larger shots as the engine components such as heads, valves, exhaust, cam and carb is ramped up aswell.

I would reccomend to buy a couple of books on the topic, just do a search on amazone and you will find a couple of them, I got one myself there.

There was a guy on this board who had a 150 plate system, and a 350hp under manifold system working together. I don't know how well it worked though.

EvilCartman

iTrader: (1)

That 6900 rpm at the line now will raise up a bit with a 250 shot. Just with a 210 shot on mine, it went from crossing the line at 6000 off the button to 7000 rpm spraying. Those Sir rods I think are rated up to 700 hp.

83 Crossfire TA

iTrader: (2)

If that thing is really pulling to 6900rpm, then you’re talking something making close to 600hp at the crank. You should be able to hit it with a pretty big shot a few times, but I wouldn’t expect it to be durable in that range, especially if you end up having to turn much more RPM through the lights.



N2O starts doing strange stuff when you get into bigger shots. Once you get past the typical 150-200hp range it’s nowhere near as easy as just figuring out how big the jets need to be to deliver the fuel and N2O and going, you start needing to do a lot of tuning. Most V8’s in that range start getting cranky with being forced to ingest big shots in the 300-350hp range, and somewhere in that range you’ll even see a mist of the stuff shooting out of the carb, basically because the engine just doesn’t want to inhale that deeply. In that range you’re talking about dedicated cam timing, very large exhaust sides and heads with >90% E/I ratios

slo406

Registered: May 2003
Location: Norway
Posts: 503
Car: 87 Black Formula
Engine: 305 Lg4 Stock. ET 16.21 with full tank & fat girlfriend clockin'.NOS cheater, not tried yet.Thats it. She's getting on a diet.
Transmission: 700R4

LMAO..!

Anyways..Im thinkin ill stay safe and go with the 200 shot...That should put me in the low 11's/high 10's


If that thing is really pulling to 6900rpm, then you’re talking something making close to 600hp at the crank

The engine is being assembled as we speak so i have not ran it since it had stock-ish internals..ran 13.2 back in the day..and revved to med/high 5000's in the rpm range...with the things i have added it should rev to 6800-7000..I pretty much copied a engine set up off of a friend and that what he ended up with.

*He was making 450 at the wheels:hail:

tommyt

With spray, You will find Your car will be just as fast if You shift it earlier than when running NA only. I would say, give it a 250 shot and shift it at around 6200. No need to rev to the moon with nitrous.
With a shot this big, You really have to watch Your tune with over 11:1 static comp. Race gas and proper timing control , as well as a dedicated fuel pump for the nitrous is pretty much a must, IMO...At this level, if You go into detonation, You will not just melt plugs, You will blow holes in pistons and split cylinders...but done right it will haul...