408 stroker with nitrous?

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slimjim

slimjim

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Is this the easiest way to throw down big numbers? Ive made up my mind and am now starting to build my 408 stroker motor. My goal is to get about 450 to 500 to the crank w/out nitrous. Its a 95% street driven car so I want it to last (at least for a little while). I want the nitrous to shut up the occasional import who decides to show off his Turbo. In order to run the nitrous I know that I need to gap my rings properly and run about a 8:1 or 9:1 compression ratio. I will be using one of the nitrous kits from summitracing. What else do I need to do in order to make this setup reliable? Im going to use the eagle forged rotating assembly. Im not taking a chance with blowing anything up so its forged everything. Im using the edelbrock heads, 750 carb, and rpm air gap intake. I only plan on using about a 150 shot. So what do you guys and gals think? Anything else Im forgeting? Any help is greatly appreciated. thanks -Jeremy
 
I recommend 10.5:1 compression with N2O. Cam needs to be around 110 lobe seperation you can choose lift and duration. Myself, I would get a custom ground cam for your specific combo. Cam ground will cost ya around $350.00. You will need to choose what system. We use Nitrous Express stuff. I like their plates. Get you a 1 gallon fuel cell and a Holley blue pump and mount these up front for the N2O setup. Tuning will be a challenge since it is for street use but just run 116 in the front cell. I like to run a tad rich on my tunes. Detonation will also destroy your investment if it ever runs lean. You will need a variety of "Pills" or jets for the plate. I usually run 3 sizes larger on the fuel side than the nitrous side. At the track we run 2 sizes larger on the fuel. Be sure to run 92-95 octane fuel in the main fuel tank.

This is my 2 cents on the matter. Some may have a different opinion! We setup the local boys chevys around here and have had no engine failures. Last one we did was a sbc 408 that runs 6.89 in the eighth on motor and 5.74 with 150 shot in a 3000lb S-10.

We also purge through the collectors so no one knows if they are spraying or not!!
 
haha to mopardart72... I wish that statement were true. Here over in California these people push out VERY high numbers with their little 4 bangers. In fact, a fellow midshipman and I turbocharged his 95 mazda miata... with 22lbs of boost the damn thing put out 422 horses to the freakin wheels... I just about fell over when I saw the monitor. All that power in an 1800 lb car is damn fast. Im sure my 408 will destroy many many hondas at the strip but I want the nitrous JUST IN CASE i line up with a car like my friends miata haha.
 
so why the high compression cuudak? Wouldnt that just increase detonation? any other tips with using nitrous?
 
You can run 10.5++ Compression on Pump fuel with Nitrous. If I were you since you will not be using it very often, I would buy a secondary Small Fuel Cell maybe 1 Gallon or so and mount it up front in the engine bay and keep it filled with 110 Octane Race gas and use a Secondary Fuel pump mounted right under the fuel cell to pump that fuel only.

This way when you are Smacking the Juice you will stay away from detonation and you can keep your compression High enough so it will still be a Lively engine when not using the NOS. You will also want some type of ignition retard that gets activated when the Nitrous soloenoids are triggered. A general rule of thumb is to Retard the timing 2* for every 50 Shot of Juice. I would use a MSD Digital 6 ignition that requires no pills and adjusts with a dial. It has 2 step rev limiter, NOS Retard etc all in one package.

Heck if you back enough timing out of it you can do it all with 10.5:1 Compression on Pump fuel easily!
 
slimjim said:
so why the high compression cuudak? Wouldnt that just increase detonation? any other tips with using nitrous?
Click to expand...


Thats not high at all! Most of these Chivys are 12.5-14:1 compression. Mad Dart added some excellent info that I left out about your timing. I am turbo'd and using the MSD BTM that pigs to the MSD 6AL and can pull 1-3* timing per pound of boost. The MSD Digital 6 or the 7 would be perfect for the N2O. Another good reference site is www.yellowbullet.com for N2O.
 
Thanks for all the great information guys! Im thinking that im going to aim for a 10.5:1 CR. The small fuel cell sounds really good however, Im a midshipman student so time is an issue. I think ill just fill up with racing fuel when I know im going to run the nitrous. Im going to use the msd digital 6 ignition so that I can retard the timing when on juice. Im going out to sea this monday so im going to start assembly as soon as i get back in september. Ill post pix!
 
This was a small block stroker in a demon, way cooler than an import any day of the week , and if it beats you then add the nitrous :smile:



 
slimjim said:
Thanks for all the great information guys! Im thinking that im going to aim for a 10.5:1 CR. The small fuel cell sounds really good however, Im a midshipman student so time is an issue. I think ill just fill up with racing fuel when I know im going to run the nitrous. Im going to use the msd digital 6 ignition so that I can retard the timing when on juice. Im going out to sea this monday so im going to start assembly as soon as i get back in september. Ill post pix!
Click to expand...

Shouldn't you be over at Annapolis, or are you in CA doing your summer midshipmen training on a ship?
 
to 64physhy im boarding the T.S. Golden Bear for my 2 month trainning around the south pacific today. Talk to you guys in two months!
 
My numbers are in my signature. This is a 414 (same as a 408, but .060 over instead of .030) which might give it a couple more HP/lbs. Those dyno numbers were when it was fresh, first run. Since then, I've dropped nearly .20 on my ET (part of that from tweaking suspension, part from motor loosening up), so it's probably putting a little more out now. With good tires, this is plenty to shut up an import. Remember, they aren't going to have as much torque.

But as I was typing that, I realized something; if you're going to be wearing bars on that collar, you shouldn't even be worried about shutting anyone up on the street. Keep it on the track, where it belongs. And it's actually more fun, as there's nothing like the feeling of the tires hooking up on a prepped track!
 
Here's what we did, and it's been flawless................
NOS cheater plate.
MSD timer module.
MSD retard box. Really makes it easy.

Adhere strictly to the specified rules and you'll have no problems. NOS leans towards safety in their 'suggestions'.
Pressures both on fuel side and nitrous side is important.
Good fuel. As you go up in nitrous, so too, should the octane.

We went to a custom grind from Bullet last year, and power jumped at the dyno.
 
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