Nervous about Nitrous

[702GT]

N2O is fun, I run a 75 shot only by fuel limitation. But the 75 is safe and still effective. If I can ever get some mickey thompson sportsman's for my front runners, I'd love to spray from a dig and turn a time slip. For now, it shreds tire in 1st and 2nd, so I'm limited to my own amusement and roll races, which suck. The nice thing about the 75 shot is my bottle seems to last forever lol.

I still have turbo envy. Always want a STS twin turbo setup.

 

[Ssiptang]

N2O is fun, I run a 75 shot only by fuel limitation. But the 75 is safe and still effective. If I can ever get some mickey thompson sportsman's for my front runners, I'd love to spray from a dig and turn a time slip. For now, it shreds tire in 1st and 2nd, so I'm limited to my own amusement and roll races, which suck. The nice thing about the 75 shot is my bottle seems to last forever lol.

I still have turbo envy. Always want a STS twin turbo setup.

Did you get a new tune for 75 shot or are you running it on stock tune?
I'm thinking about doing this because my car only has 6k miles. Don't wanna go big untill my warranty is out.

 

[SRTthis]

Idiots can fuck up anything and give it a bad rap. Do some research and you'll be ok. It goes without saying, start with a small shot and work your way up. Get a wideband and window switch at minimum.

pretty much...

 

[Corpo]

MBT = Minimum Best Timing. In other words the ignition timing in which you make maximum torque at a particular RPM/load, where advancing further results in no increase or a decrease in output. EGTs increase exponentiaally as you retard from MBT, which is why most of us are just fine with "conservative" ignition timing that is retarded from MBT, but as you get more retarded the EGTs will start to increase more and more rapidly.

As for acceptable EGTs, it depends on the build of the engine. 1600 F is kinda widely accepted "high", which Ive always been able to stay under. I personally think you can go a bit higher before things melt, but Ive never tried for obvious reasons.

That reminds me. Do you still have cats?

I dont have cats anymore, no. Why?

 

[702GT]

Did you get a new tune for 75 shot or are you running it on stock tune?
I'm thinking about doing this because my car only has 6k miles. Don't wanna go big untill my warranty is out.

Yes, I had it dyno tuned. Always tune for your setup, or at least get a dyno run in, to make sure it's safe. That's how I found out I was going to be severely limited on my shot size. We found fuel rail pressure was getting drained on initial hit. Pressure dropped from 40 to 15 psi within 100rpm's and then FPDC spikes and catches up. I'm going back tomorrow to do all 4 gears on spray. My tuner is worried in 1st and 2nd becuz the engine will rev out faster that fuel rails might drain or starve the motor. We want to make sure. The AFR didn't seem affected by it.

How some of these guys are running 150 shots on stock pump and say they're fine I'll never understand. I asked my tuner what the fix for me is and he says my options are slim. He says GT500 twin pumps will lower my FPDC but not stop the intial drain on the fuel rails. Either way fuel rails take a hit that he can't compensate in a tune for. I can go return style fuel system, or make a dedicated fuel supply for the fuel solenoid, and tie the fuel pump into my arming switch. I'm at a loss for now. If I'm going to dump almost $1,000 on my fuel system, it won't be to run a nitrous kit. Nitrous was supposed to be a cheap easy power adder, but the cost of running it safely and properly keeps going up.

 

[Full_Tilt]

Separate fuel system for the nitrous perhaps?

Its something Ive alwasy wanted to try, just a basic little pump, FPR, and take for delivering high octane fuel with the nitrous.
Hell, maybe even propane, atomization should be really good...

 

[702GT]

Separate fuel system for the nitrous perhaps?

Its something Ive alwasy wanted to try, just a basic little pump, FPR, and take for delivering high octane fuel with the nitrous.
Hell, maybe even propane, atomization should be really good...

Atomization is in delivery method and location. Whether its 87 or 100 octane doesn't matter. I wouldn't jump into spraying 100 octane with 91 already in the tank. If you tune for the fuel you run you'll be safe. If you run higher after the fact you could potentially lose power and at the very least not be very efficient.

I've seen dedicated fuel cell setups for wet kits. I won't go that far if I don't have to. And until I step into the 150 shot realm, I shouldn't have to. The only reason the fuel pressure drop is so dramatic is because it's happening right under the fuel pressure sensor. I just don't want it fvcking with the tune. Tomorrow I get my dyno time, then we'll see wtf is up. A .024 fuel jet shouldn't wipe out the fuel rail, I'm more concerned with fuel pressure spikes when the FPDC catches up. It happens so fast, we're talking 100-200rpm. I just don't want the fuel pressure to come back too hard and blow shit apart lol.

 

[3VPOWA]

Yes, I had it dyno tuned. Always tune for your setup, or at least get a dyno run in, to make sure it's safe. That's how I found out I was going to be severely limited on my shot size. We found fuel rail pressure was getting drained on initial hit. Pressure dropped from 40 to 15 psi within 100rpm's and then FPDC spikes and catches up. I'm going back tomorrow to do all 4 gears on spray. My tuner is worried in 1st and 2nd becuz the engine will rev out faster that fuel rails might drain or starve the motor. We want to make sure. The AFR didn't seem affected by it.

Any update on this?

 

[fdjizm]

If I had a 5.0 like u, I wouldn't get it.

There is your first problem, you feel lesser for some reason?
my car has 320hp and it feels like a million bucks, I've been in love with it since I got it and no matter what passes me or has more power I will still love it!

I just never had that need inside me to be faster than anyone I just don't care enough to be honest I enjoy my car EVERY DAY, I customized it to my preferences, who cares who is faster?

On topic, save up for and SC if you have a serious need to compete in your daily competition of whatever it is you are competing against, nitrous is temporary power won't do much for your daily driving experience. If nitrous actually pleases you and it's not just for "keeping up with people" then definitely do it the kits out there now are pretty safe.

/rant

 

[702GT]

Any update on this?

Yep. Fuel pressure drop is consistant in every gear and only lasts about 100 rpm then returns to normal as the pump catches up. The drop varies and drops the most on the intial hit. The higher the rpm the hit, the less it drops because the pump is already ramped up. AFR is steady, never flinches.

IMO it might just be to an advantage that the nitrous fuel supply taps right at the sensor. While it shows up on the dyno, it allows the FPDC to ramp up immediately and return pressure to the rails. I'm confident the stock fuel system will handle the 100 shot, but for now I'm happy with 400/400 off the 75 shot.

 

[Corpo]

Well I figure this is a good place to post this. So I just datalogged a 125 shot. I have a fuel pressure drop as low as 17psi when the n2o solenoids pop open after shifting into 3rd. However the afr goes up to 13.2 for a few hundred rpm then returns to... Uh... Normal I guess (can't remember the number off the top of my head) anyone willing to look at my datalog? I am logging analog 1. It appears 5 degree's of spark is pulled from my n/a tune. Also what pid do I use to log knock?

 

[Full_Tilt]

Id like to see it.

 

[Corpo]

So I had a thought... My rpm window is set at 3500-6500. I shift at 7000. I found there is enough nitrous in the system to push me to 7000 as is. The power is still there. However I am beginning to think it is screwing with the fpdm like that. Because at 6500 when the solenoids shut just before a shift the fuel pressure spikes to 60 when I shift, duty cycle drops to nothing then I'm back on the throttle at 4500rpm. The solenoids open instantly and the fuel pressure drops to 17psi. Then duty cycle has to catch up, causing a 13.2 in the air fuel ratio.

I'm gonna try adjusting my window to 6800. The only reason I put it as 6500 was so that last 500 rpm before the throttle body shuts the fuel gets sucked into a intake runner instead of possibly stoping stationary and pooling. That was my theory anyway.

Oh yeah and I think my tune's normal afr is 12. Bit lean?

 

[s8v4o]

Oh yeah and I think my tune's normal afr is 12. Bit lean?

"Normal", is that on or off the juice?

 

[702GT]

11.7~12.0 is where my AFR plays on spray. 12.7~13.0 is my N/A AFR.

Are you saying when you shift from 7,000rpm you fall all the way back to 4500rpm?

How big of a shot are you running? (N2O and Fuel Jet sizes?)

 

[Corpo]

Going over my datalogs... My na tune seems solid at 12.4 at wot, shortterm trim is 0.85. Spark is 33. My nitrous tune the afr is 12.4 without spray. Short terms is also .85. Spark peaks at 28. When the juice hits my afr drops to 10.9 but works its way to 12. Short terms all hang out at .85 through wot.

I did change my window to 4000-7000.

Shifting at 6900 landed me at 5300.

Running .54 and .34 Zex 125 shot.