69 N.O.X. RATT

Looks like a nice system. Are you running a pump gas heads up class? if so why the extra tank ?

You will be fine, remember too much timing and too much fuel hurts nitrous engines long before being too lean will. Anyone who tells you otherwise does not know nitrous engines.

If you have adjustable rear shocks tighten up the extension a little when you hit it with the 150 shot. I do not run on radials but the 150 shot adds around 200-250 pounds of tq and it will try to send the rim into the pavement if you do not control it.

Sort of a matter of taste, but I prefer a bang button over a purge.

bluzman2004

Hey, I'm glad you happened onto this thread, Sir! The more people "in the know" I talk to seem to definitely agree with rich isn't really safe approach. Do you use A/F ratios or just tune by the plugs or both? I have the ability to set a Nitrous A/F target and the computer will keep it there. I was going to start at about 11.5 or 12.0 for a start, but I know guys running 13.0 and never break anything.

I already had the car setup for N/A last year and everything was running good, but I am close to being capped on fuel pump flow and fuel line size for both the feed and return. I was going to go to a larger fuel pump and larger lines everywhere and just use that for both, but changed my mind. Since I drive this alot during the summer, I decided to leave things as is and add the separate fuel system that will only be pulling current and flowing all the extra fuel when I arm the nitrous. I already had a fuel cell and fuel pump, so it only cost me for a regulator.

I know everyone has an opinion on this, but I know guys that run with 250 shots and run race gas in the cell alone and pump gas in the tank. What do you think about that??

I have a digital 6 ignition, and have the retard set to 6 degrees. Does that sound like a good starting point?

I will change the shock settings. I have the QA1 single adjustable coilovers. I've been having to run them on a very soft setting and that made the car hook great. They might limit the adjustability some without the second adjustment. What would you do for a 4 link change? Would you say run what worked N/A and see what it needs?

brngrhd

I can't really see by your pics how your running your fuel system.... with the pump pushing fuel pressures up to 45+psi and your nitours system runing lower how do you have it setup? i had a 100shot on my pt cruiser and had the tune setup for the big pressure..... fuel pressure was set up at 58psi for motor and nitrous...... the way the pt was setup was i was pulling fuel out of the end of the fuel rail and then goes to the nitrous solenoid..... as for your tune...... i'd set the tune based off a/f and check the plugs after one pass. so you can go to the dyno get it as close as you can then go to the track put in the fresh pulgs and read them at that end.......

69 N.O.X. RATT

Until I recently installed a data logger I had no access to AF numbers. Once I calibrate the sniffers I will have numbers on that. Reading plugs has been successful so far.

I would not run any richer than 12 to 1, and I would pull a more than 6, probably 9. You may end up feeding it back to the engine, but the slight reduction in power will make your maiden voyage less dramatic,and safer if you miss something. Cars that are set up for nitrous react very favorably to even small shots. Your tight converter is going to really benefit from all that extra tq.

I am personally not a fan of the race gas in the extra tank deal, but mainly because my engine is 14 to 1 compression anyway. I know lots of guys that do it and get away with it, just not for me. If you do it don't skimp on fuel, nitrous engines hate cheap fuel and will punish you and your pocket book if they start rattling the rings too much.

If the 4 link is set up in a good spot for NA, 250 hp of nitrous or less is probably only going to need a shock adjustment. I am no 4 link expert though.

If you shocks are adjustable for extension it would make since you had to have them soft to get them to hook. You are not making enough power (too tight converter, etc) to make the rear end work and the shocks needed a soft enough setting to push the tires into the ground and get some traction. I am sorta in the same boat. if I do not hit mine with 1200+ hp the car will not leave the line very well and gets loose down track. If this is the case tighten them up a bit before you spray it.

When are you going to make some test runs?

bluzman2004

Steve, I saw your emails today. I've been on vacation for the last 2 weeks. If you still want to do some EFI stuff. Let me know.

I think the answer to your question on the fuel system is that I have 2 separate systems. The one for the motor is normal with a pump in the back feeding the fuel rails and back to the regulator and then returns to the tank. The nitrous fuel system has a pump that feeds a dual inlet regulator. I have the return going back to the fuel cell and the second inlet, which is just a feed-through actually, going directly to fuel solenoid. so I can adjust the fuel pressure for the nitrous just like the EFI system and the fuel jets are flowed for the higher fuel pressure.

bluzman2004

That's probably my problem, I haven't hit mine with 1200 hp yet!!!!

Yeah, my motor is definitely a pump gas motor. It's only a 10.5 CR and aluminum heads. The cam isn't exactly a N2O grind, kindof a tradeoff grind we did at work. Very serious lobes though as for as agressiveness. It is a solid roller ground on a 110 LSA, with 261@.050, 268@.050 and installed at 106 if I remember right. Also the motor is a 434 sbc, too.
I probably won't go past the 150 shot on pump gas really. There's no real reason to chance anything for a few gallons of gas! I mainly race the 7.0 index class anyways since I can do that N/A on pump gas easily.

I won't get to the track for a month or so. It is starting to get cold here now. I might put it on the chassis dyno and see what it does with some short top gear pulls. Then I can look at the plugs and a/f easier.

enkeivette

Siiick. Cool car too.

69 N.O.X. RATT

The more I learn about nitrous engines the more I think camshaft selection (for moderate amounts of nitrous, i.e. 400 and less) is really not that important. If a guy is only going to run 100-300 or so, no need for anything nitrous specific. In the upper levels the main benifit to a nitrous cam is to help the engine shed heat and not burn its self up. I ran 400 through oval port heads and a cam that was certainly not a nitrous grind; 255 / 262 on a 112. I went 5.09 at 2553 pounds with a pump gas 454 and that combination. Made well over 100 hard nitrous runs with that and never hurt a thing.

If you car runs 7.0's I would think that .4-.5 /10ths should be doable with a 150 hit, maybe more.

Run it fairly lean, pull lots of timing and adjust from there.

bluzman2004

Thanks for the all the info. I talked to a guy that is running really good too and he is running a defiite N/A profile cam, so I think you just run what you got and take it slow from there unless you are trying to sqeeze every last hp out. Just like you said!

I can't wait to see how it picks up. I like to play with this stuff anyways, so it will be fun just working through everything at the track. That's why I do this stuff anyways, not really to win anything. Luckily, because I never win anything.

My last pass at the track this year was a 6.90 and it was on accident. I was racing in the 7.0 class and was short shifting at 6000 and even let off at the last second since I was so far ahead. My MPH was down 10 mph due to coasting the last feet and still ran a best time of the year. I have no idea what I did different, but it was cooling down alot and about 10:00pm. That's all I can think of.
Thanks again, I will post some results eventually.

Ron T.

69 N.O.X. RATT

3 speed autos will always run faster if you short shift them in 1st gear. They hang on the converter longer.

Let us know how it goes when you make some runs or dyno pulls.

bluzman2004

Now that I didn't know! I'm going to owe you a beer if we ever meet, now. Since my gearing is setup for the nitrous I've only been using 1st and 2nd gear at the track (1/8th mile track) on the motor. I go through the traps right at the end of 2nd. I'm going to have to play with that, too.