OutlawZ

iTrader: (4)

I run a 15lb'er and I plan on a NANO setup...... as well as a heater. i haven't had a problem with heating in the summer obviously but pressure drop is our biggest concern....

I generally run 3 times with one 15 lb'er and then we swap it for a fresh bullet..... I guess iwth a nano setup i'd get more like 5 runs....

JL ws-6

iTrader: (50)

I'm not a big fan of the nano to be honest. It's another bottle to fill, plus the car going a little fat at the top end can actually help save parts, the car losing a little pressure at the big end can be a good thing... that's the down side of the nano that noone talks about.

Look at it this way, how many people do you know that run 1/8th mile with nitrous and are competitive, then they try to fun 1/4 mile stuff and end up hurting alot of ****? It's because that back 1/2 is where the damage happens, if you eliminate the enrichment factor, how many more people do you think would be hurting stuff? My guess, alot better yet a TON.

Nano, no thanks if I'm that worried about the presure drop I'll put 2 bottles in the car and Y then together. And, change them both after 3 runs, instead of changing the one 10 lb'er after one.

Coach 02 A3 Z/28

iTrader: (10)

Great stuff guys. Congrats.

Coach

OutlawZ

iTrader: (4)

how does your engine mgmt system work????? cause mine hunts for A/F ratio the whole run and compensates...... So if we want 11.5:1 it'll find that A/F and stay there. If the nitrous press starts dropping it'll pull fuel to avoid the super rich condition....

But I do understand where you're coming from....good angle of thought....

JL ws-6

iTrader: (50)

I'm still on a stock computer, and it's tuned in open loop. I go WOT, the fueling is set so it stays the same the whole run... with what you're doing ( I assume you have widebands in the system) it's adjusting as you run it, I don't have that luxury, at least until I put a BS3 in the car (probably another item of contention during my break next year)

Just be careful with that nano stuff, I knwo more then one person that has had bad results because of what that does. If you shift lower then what the car goes thru the traps at, I'd add some fuel at any rpm above your shift points, it will help save parts at the top end. Letting the a/f drop back down to 11 to 1 for the last 300 feet, might knock a mph off the times, but your pistons will thank you for it.

OutlawZ

iTrader: (4)

yeah i run an XFI setup with a wideband tuned in closed loop..... I've talked to others and bounced stuff of my tuner and he runs ALL his cars in closed loop although others have said it will lead to motor death...

But he tunes a BUNCH of PSCA cars running up to three to four units on drag radials... Nitrous cars deep in the 7's so I trust that he knows what he's doing with my junk...

Good luck during your downtime man. Let's see that thing next season on kill....

kp

iTrader: (34)

I run in wideband closed loop 98% of the time with the BS3 as well. Only time I dont is when I'm looking for internet glory timeslips, I can usually eek out a few hundredths spending some time with the tune and not using the wideband.

A lot of tuners dont like it because it takes them out of the equation. But I can change heads, cams, intakes, pulleys, fuel (C16 vs Q16) and see if the change makes a difference in a couple passes. Hell even the charge pipes can blow off at the starting line and the car still runs fine - two seconds slower but the a/f is right on.

OutlawZ

iTrader: (4)

I agree 100% KP..... I can't see any reason for not using closed loop.... once my car finds 11.50 it locks on...... it's iffy off the line cause it swings around and sometimes overshoots... but generally after like .2 it's found where it needs to be and it's on....

kp

iTrader: (34)

Yea, off the line is the rough part. It tends to go way rich when I let off the trans brake (the closed loop is disabled when the brake is on) but it pulls back pretty quick. I have shut it off below 6K and got rid of the overshoot but in reality it didnt change the 60' much. In the heat is where you will some difference, when its cool out the overshoot actually helps a bit with detonation.

OutlawZ

iTrader: (4)

yeah my datalog recently when we changed jets and went to a bigger shot it got weird off the line.... it stuttered a bit (which was funny cuz it ended what would have probably been a giant wheelstand which was good)..... A/F ratio swung to about 9.25:1 for a split second, then corrected and shot back to 12.1, then back to 10.2:1 and then came out to 11.7:1 and from then on was good. So I have to talk to my tuner about the overshoot cause if the car is going to stutter that can't be good.... I need the car pulling like a freight train outta the hole.... So yours looks the same on initial launch??? My car's nitrous is disabled with the brake on so it's not doing any funky fueling at that point....

I have to figure out why it's overcorrecting like that though..... maybe have my tuner smooth out that area and tighten up it's limits to keep it from overshooting... just in that area...

JL ws-6

iTrader: (50)

The closed loop just isn't really an option with the factory computer because it doesn't use a real wideband, plus with the race gas the stock o2's are really not gonna be happy.


When I get the aftermarket PCM in the car, I'll look into it. Can't hurt. One thing I will make sure it does, is start rolling the a/f a little richer at the 1000 foot mark to help keep things alive (roll it from 11.5 o 11.1 to 1 for the last 300 feet)

OutlawZ

iTrader: (4)

Hmmmmm... That is a good idea. I'd have to look into the XFI to see if it allows a richer fuel mix on the top end. I think generally at least AFAIK, you can select a target A/F ratio but it is in effect for the entire run.... I don't know if the capability exists to fatten it up on the big end. At least in the XFI.......

but that is a good idea.....

JL ws-6

iTrader: (50)

I dunno if you can do it, but see if you can set the target a/f by rpm. I assume you shift the car at about what it goes thru the traps at, if that's the case then just have the a/f start to roll down after the shift point, so if you were to miss a shift or shift late it will start to roll a little more fuel in. A/f by RPM, I dunno if it's possible, but if it is that would be the easiest way.

I don't run a nano, and as the bottle pressure falls off a little that kind of does the same thing being that I have my car tuned in open loop and the a'f is pretty much a set thing

Tony Shepherd

iTrader: (4)

Actually on the top end when you are past the torque peak (5200 for most engines) you can lean it out a bit because the engine is pasts its heaviest load. I just leave mine the same air/fuel. Some n/a guys lean it out a bit after torque peak. Ed Wright is one of them.

When I mean lean it out a bit....I mean very little.

JL ws-6

iTrader: (50)

But in an effort to keep the motor from eating itself up on the top end (nitrous motor's to be specific) wouldn't you want to richen it up a touch, or start to roll some timing back out of it past X amount of RPM? That to me would make more sense..

Tony Shepherd

iTrader: (4)

Every combo is different so it is hard to say but as long as your air/fuel is in a safe zone throughout the whole pass you will be fine. Riching it up at the end can also do more harm than good. If I was at 10.8 air/fuel from 3000-8000 rpms and my torque peak was at 5500 I would try to go 11.00 air/fuel at 5600 and up. Thats just me though. Everyone has their own opinions.

Hodgesz28

iTrader: (28)

My car was in it prior to me buying it when it was held in Maryland at MIR. It got picked but got eliminated in 1st round because the nitrous never came on......it was the 10.5 index......run consistant and be either mid 10's or high 9'd you'll get picked......plus it helps to have a decent looking car to.....or a truck thats fast.

kp

iTrader: (34)

Mine does the same thing but its all before the 60' mark. I limit the positive correction between 3500-6000rpm to +4% so that helps it out a bit. 1.25-1.27 60 foots are good enough for me..

It looks bad on the logs but I can easily make it not do that and it really doesnt affect it much 60 foot wise. I imagine an N2O car has a few more things to contend with on the launch, the initial bottle pressure hit when it comes on amd the fuel pressure taking a bit to stabilze.

kp

iTrader: (34)

After peak torque efficiency drops off pretty good, the engine just cant use the same amount of fuel. its something you have to experiment but between leaning it out at high speed and high gear retard I pick up a bit in the 1/4.. Just something you have to experiment with some if you are looking for that last little bit. Not something to be fooled with when you are just sorting out a new combination..

OutlawZ

iTrader: (4)

Yeah Tony I know you can do that in the target A/F ratio map when you are running motor but if you run in closed loop once the power adder enable comes on it targets the A/F ratio in the "target a/f ratio" in the nitrous parameters table... it ignores the target A/F ratio table based on RPM/Load..... And you can only put it one target A/F...... So how are you leaning it out past torque peak on spray?????

I can do it on motor but not on the bottle..... at least not in closed loop. hell not in open loop either cause then it won't be correcting ****....