331/347 With NOS...Anyone?

[94GTLaserRC]

Just out of curiousity, is there anyone around here with that setup?

What are considerations when planning for NOS with a stroker? I know you need a lower compression. What about Cam, fuel system, etc?

Im just continuing the future 347 research..
Thanks
RC

 

[SQUEEZE&STROKE]

331 With Nitrous-(150-200 Hp Wet Unit)
Srp Flat Top Pistons-10.8:1 Compression
Eagle Cast Steel Crank
Eagle Forged I Beam Rods
Rings Gapped To 24 & 26 (for The Nitrous)
Main Girle W/ Arp Studs
Head Studs

255 In Tank Fuel Pump
Afpr
42lb Injectors
80mm Mass Air
Peformer Rpm Intake
Crane 20/30 Cam
A9l Conversion Harness

Timing Retarded To 6-7 Degrees Btdc
Autolite 23's
Msd 6al, Msd Probillet Dist, Msd Blaster Coil

 

[mootang]

why don't you want to use the vortech on your stroker?

 

[DougNuts]

You don't need lower compression. Just retard your timing a bit and let it rip.

I also think you're not supposed to have a lot of heat built up in your motor. Make sure you have enough fuel, a fuel pressure safety switch and forged rods and pistons.

 

[Joes95GT]

First off, I'd like to say that I consider normal street compression anywhere between 9.5 - 11:1. 11:1 being the very extreme.

Nitrous, because it's not used all the time, NEEDS regular compression. If you're using something with 8.5:1 compression on the street, it's going to be a slug.

A car with 10:1 or 10.5:1 compression can run very hard with a 150 shot on 92 or 93 pump gas. The block is another issue.

A good N/A 6200 RPM shift 347 will make ~450 FWHP. If you go with a custom cam, you'd see another 150 FWHP from a 100 shot. Approximately 600 FWHP won't last long in the stock block.

A 50 shot in a good 347 will still make damn near 475 RWHP.

Sure would be a fun street car...

Joe

 

[blksn955.o]

I know N.O.S. (and I belive its an industry standard) rates the power level on the kits based on a 350/351 motor, so if you have a motor close to that CID then the hp will be closer to what it is rated at. The smaller the motor the less hp you get, so if your running a 150 shot on a 302 (again based on the 350/351 motor) you see less hp. Drivetrain loss is also an issue with N.O.S. as they are flywheel hp. numbers and not rear wheel numbers. N2O will give you more of a "hit" when you go up in CID and you will start to get more hp per jet rating once you go over the 350/351 CID standard. For instance a bud has a B.O.P 400 with ram airIII heads that has a 150 shot on it, in reality its more like a 160-170 from the extra displacment.

Some kits do use the rear wheel hp number from dyno testing the whole setup. NX is one of them and that is why people get more hp with them than others.

As stated above comp. is not realy an issue until it goes over 11:1, I know a shop that has a 12:1 motor with a 250 shot on it. They said the tune starts to get real tricky around this point and if they went higher things realy start getting tricky.

Just make sure you run the safty stuff, window switch, bigger fuel pump, fuel press. shut off switch, and run an aftermarket ign. Forged pistons should be used if your going to go 150 or larger in shot size (150 can be used with hypers but its preaty mutch the max). Run a colder plug at least one range or two colder. ***also if your running more comp. like in the upper 10:1 range you should run a colder plug N/A as the added heat from the added comp. should have a colder plug (than if stock comp. was used with whatever heads used)*** and never ever run plat. plugs on a n2o car. If you want to get the most out of launching a n2o car and you can slow the spark advance that helps soften the hit and let you get a better hook and go from a stop. remember Rich is B**ch and Lean is Mean.

 

[Joes95GT]

The CID stuff is partially true. Remember, just like anything else, it's "advertising". On the 302 motor, anyone can "claim" a 150 shot will give them 150 horsepower - just zing the motor to 7500 or so. They also make no mention of the size of cylinder heads or camshaft timing.

I've heard of guys picking up 300 WHEEL horsepower on the second of a duel stage nitrous system (the second stage was a 175 shot).

It's all in the motor...

Joe

 

[blksn955.o]

The heads play a huge part in it. The saying goes a good N/A motor is a great n2o motor.

I think thats one reason the ls1 and 2v/4v 4.6 like the bottle so mutch good amount of comp. (esp. the ls1) and heads that flow preaty well.

 

[VibrantRedGT]

Now you want NAWZZZ?

I'm going with a high compression 347 (RPMII or Victor intake, AFR 185's, Comp custom cam, aluminum flywheel, 1 3/4 Long tubes, 3 inch exhaust and all that) but mine will be straight up, no power adder.

 

[stprorolla49]

RC, just pop the s-trim on that 347, and call it a day....forget the NAWWWZZZZZZZZZ

 

[94GTLaserRC]

The ONLY 2 reasons I would ditch the Vortech with the 347 is to

1. Make the tuning etc less complicated, and

2. (more importantly) to help fund the project. My polished VOrtech with chrome PP should be worth close to 2k, which would help with the finances.


Joe, I guess I can see how yours goes first, then decide, but remember with the AODE, Im pretty much stuck with my shorty headers, so I will be at a slight disadv already..

Thanks
RC

 

[slvrbullit302]

I just got thru installing my DSS 331 10.7:1 motor. It was ordered to be a nitrous motor and will be seeing a 150shot of nitrous in a week or two after the break in of course. I will post the results both n/a and on the spray of course.

 

[94GTLaserRC]

That would be awesome.

What about those 30#'s though
RC

 

[slvrbullit302]

That would be awesome.

What about those 30#'s though
RC

Gonna do a dyno session first and watch the air/fuel, they were fine on my 306 and 100 shot, but then again it didnt make the power this one will make.

Also on the 306 and 30#ers the air fuel was 13.5:1 without any electronic tuning of the computer, only tweaking the fuel pressure.

 

[Redsnk95]

I'll let ya know how it works. My 347 11:1 motor will make 425rwhp on motor and the plate kit is good for 300hp extra...I will keep it at 650rwhp. The B50 will handle that despite all the nay-sayers.

Troy

 

[blksn955.o]

If you run a wet kit you dont have to worry about maxing out your inj. just the pump and lines/rail become the limiting factor (well noids, and jets too). If you use a dry kit then the need for larger inj. will be there as it puts alot of stress on them. Both have pro's and con's but nothing major if you run the safty stuff.

 

[Grn92LX]

That would be awesome.

What about those 30#'s though
RC

Rob, keep your 36# injectors for this combo. The other night when I was out playing around in my car I felt like seeing what my injector duty cycle was. I punched it and looked at my PMS screen. I took it to like 5000rpm and my duty cycle was 70%. 80% is about the max you want. So i'm thinking when i'm pulling the car to 6500 i'm sure my duty cycle will be around 80%. So up top, these 30's are about done. Your looking to build a 347 and then put spray on it, you'll definatly want the bigger injector if your running a dry kit.

I would build the combo to run hard on motor, then hit it with a 100 dry shot for the knock out punch. If you dont already have one, you definatly want a 255 high pressure fuel pump.

If you were looking to build a nitrous motor, I don't know how happy you would be off the bottle.

 

[94GTLaserRC]

Troy, not really sure what you said...I dont know what a plate kit is, and I dont know what a B50 is

Mike, Not sure if I WILL do this, but I just wanted to know what/what not I will need.. Yeah I would keep the 36's if I did that, and I already have the 255.

Im waiting for your numbers and some others to see what I want to do. Remember, Im already at a disadv b/c most of you guys are going 1-3/4 longtubes, and Im pretty much stuck with my 1-5/8 shorties.


Thanks
RC

 

[DougNuts]

I'm going with a high compression 347 (RPMII or Victor intake, AFR 185's, Comp custom cam, aluminum flywheel, 1 3/4 Long tubes, 3 inch exhaust and all that) but mine will be straight up, no power adder.

I'm doing the exact same thing except mine will be a 357 and I won't have long tubes at first. I have some shorty swap headers already purchased. I'll upgrade to a full 3" exhaust and kooks headers once I get the car running good.

 

[VibrantRedGT]

Rob, keep your 36# injectors for this combo. The other night when I was out playing around in my car I felt like seeing what my injector duty cycle was. I punched it and looked at my PMS screen. I took it to like 5000rpm and my duty cycle was 70%. 80% is about the max you want. So i'm thinking when i'm pulling the car to 6500 i'm sure my duty cycle will be around 80%. So up top, these 30's are about done. Your looking to build a 347 and then put spray on it, you'll definatly want the bigger injector if your running a dry kit.

I would build the combo to run hard on motor, then hit it with a 100 dry shot for the knock out punch. If you dont already have one, you definatly want a 255 high pressure fuel pump.

If you were looking to build a nitrous motor, I don't know how happy you would be off the bottle.

Hmm...I have 30# injectors too. I wish I had kept my 42's since my MAF is calibrated for them.

Mike, I have an older model PMS. Does the PMS let you mismatch MAF calibration and injector sizes like the Tweecer?