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Discussion Starter · #1 ·
I wonder how those of you who are into nitrous check and maintain your tuneups ? I made my own flowing pressure gauge from one I got from MSC and use a 73 jet for flowing. Do you flow befrore or after each pass, and do you check and adjust as necessary from one event to the next. Last time out I ran with 6 PSI before the last pass. Last night I tested it before the run and it read high so i readjusted it back to 6 psi.

Is this something I should be doing at dififerent sessions or should the pressure not change. It's a new holley 803 regulator. I wonder if I should have left it alone since I had not touched it since last pass in December ?

Thanks in advance
Rob

BTW my lone bottle pas was a 10.23 @ 128 1.48 60' :sad: It went straighter on the launch after changing the preload and installing Hotchkiss trailing arm braces, even after forgetting to air up the bag again. :eek:

I also won $20 in a grudge race against a SBF Mavrick even though my nitrous did'nt activate. (blown fuse) Would have been a good run but they blew the motor on the line.

After that my car would not crank and no spark and found some melted wires still have to trace the problem down, but it's not the MSD or coil.

That was the first time I had to push it on a trailer. All in all it was a decent night. I ran a 10.80 on my nitrous tune and I think I can better my best NA with some more tuning and better driving job. I need more seat time as I keep making small errors early.

Still looking for a 9...
 

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Check the pressure once and forget it, unless you change jets. Have a viewable fuel gauge,minimum a guage off the regulator(not liquid filled). Set it .5 above the desired setting. Purge the kit right before you stage. Before you stage make sure both bottle and fuel pressure are at the desired psi.

Assuming at minimum a seperate regulator for the nitrous. A dead head design will creep (increase pressure) when not in use. If you are running one pump to two regulators and drive it often that nitrous regulator will likely see 9-10 lbs before its purged. Typical dead head problem, and normal.

Always purge(burp) the system before you adjust the regulator and stage the car. I would check a plug or two and heat or cool the nitrous bottle between runs, check fuel on the purge. I would never flow fuel or nitrous between rounds.
 

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Flowing between rounds depends on a few things. If you are running bit hits or trying to run very consistent it is necessary to flow the system between rounds. I run 300+ hits in my 454 so I ALWAYS flow the system between rounds. About 50% of the time I will have to make an adjustment. I adjust my tunes down with in .1-.2 lbs flowing pressure. It is not uncommon for my car to run within .002-.005 run after run.

If you are running a 150 shot and are not too concerned with it running extremely consistent then I would flow it once when I got to the track and forget about it.
 

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Discussion Starter · #4 ·
I am into consistancy, kinda hard to evaluate changes without it. I shut the pumps off before staging to cut down on the creep, have'nt had any problems doing that yet. I would like to work up to a 250 hit but am going to need more suspension work first, or delay full the hit. The nitrous fuel side gauge creeps even during a run to 9 psi in the lights. I use a liquid filled 2 5/8 pro comp gauge for that side and seprate Holley 803 regulators.

I got a chance to go over the log of my last runs and it seems to have run about right given teh 60' and slight weather changes.

I sure like those 1.40 60's better. LOL
 

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As mentioned, you have to be VERY careful with a liquid filled gauge. Unless you "burp" the gauge all the time, they will show all over the place. I wouldn't set flowing pressure with a liquid filled gauge. Your pressure should not be moving going down the track.

I wouldn't worry about the creep. It helps with the leaness that is there for an instant and actually can be good.
 

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Discussion Starter · #7 ·
I have the liquid filled gauge mounted on the cowl. I do not use it for checking flowing pressure I use a flow tool similar to the Nitrous Supply one. The fuel pressure creep during a pass I mentioned above is on NA runs.

System is 2 #8 lines out of cell into old style Russel filter with dual in/outs, then to 2 Holley Blue pumps, then into a Y block into #8 line to the front, seprate regulators for carb and the plate. I do not use a Hobbs switch, I have seen more problems with those than anything else. Here is a shot of the motor which shows how the front is set up.

 

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What is your tune, jets, bottle pressure, timing etc. What does the car run on and off the juice?? When do you engage the nitrous??
 

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Discussion Starter · #9 ·
I run 73 jets squared in a Pro 2 stage cheater plate, (only on one stage still) Fp right now is 6 psi, still experimenting with that but it's real close. Bottle I like to see at 950. The car has been 10.66 @ 125 on NA tune. Friday I ran a 10.88 and 10.80 @ 123 with the timing out for nitrous, so total was 33*. Throttle switch activation. I think the tune is real close now and am concentrating on making several clean good runs with no changes. My 60's are erratic and I need to address that, and my driving cause I keep shifting late out of first and that seems to really hurt the ET. If the track is good it will launch well if not its all over the place.
 
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