Anyone use an inline nitrous filter? (or "My car slowed down, why??")

[John_D.]

Ok, so a month or so back, I ran a 13.2 on ET Streets (borrowed). And 13.4 on my street tires.

Saturday, I put on 15" skinnies in front, and bfg drag radials on back. I ran 3 13.7's, and a 14.0 on the last pass.

What changed since a month ago?

Added an MSD dis-4 ignition.
Better tuning (so I'm not running rich - was 96-98 o2 readings, now 92-93).
Full tank of gas (I needed 93 octane, and the tank still had a bunch of 87 in it...)
Lowered 1.5" all around.
Bumped the temp on the bottle heater from 85 degrees to 95 degrees.
And the one I suspect the most, I switched to an old style NX 15lb bottle and added an in-line nitrous filter.

The car seemed to have a harder initial hit (with the warmer temp on the bottle heater) but did not pull as hard down the track, which makes me think the filter can't support enough volume for the 67 jet.

I bumped to a 70 jet on the final pass, and the car ran even slower... That's when I got a 14.0, compared to the 13.7's I got on the first 3 passes.

I did get a little better 60' time on the 70 jet. (1.9 vs 2.0)

Eventually I need lca relo brackets and less air in the bfg's... But I was getting 13.4 on my street tires with only 2.0 60' times a month ago. So the 60' times are not the issue, not comparing this run to a month ago.

There's just not a good reason to be pulling 13.7's now, with having dropped 68 lbs off the front of the car by putting skinnies on it.

Unless that filter (or the valve on the NX bottle) are restricting the nitrous flow to be less than what my jet needs.

Thoughts, ideas, help??? [img]smile.gif[/img]

[Nachius]

I know Ironman was having issues with his and after replacing it he ran a lot better, but I think his was clogged. There are different filters some of which are a LOT bigger than others which did you get? I have a LARGE competition filter at home I can get the part number off of sometime soon. Also I believe lowering the car can hurt times, but that should only be the 60' so I don't think lowering would have hurt much!

I would try a run without the filter and see what you run and if you run better get a bigger filter!!

[John_D.]

I have a dual male fitting that I can use to bypass it and see what the difference is.

I liked the idea of having a filter, but not if the nitrous can't get through!

The dimensions are about 4" x 1.75" (just going by memory of the approximate size).
It's a NOS brand.

[slacker69]

You do not need the filter. As long as you purge after getting your bottle filled to make sure line is clean. You arent getting any kind of knock are you cause the filter should not change the speed of the nitrous for one jet to the other. if you are slowing down by putting on more ntirous there is another problem. Now i am not saying the filter is slowing you down but i would say it isnt makeing you go slower with more nitrous

[John_D.]

When I ran my 13.2 a month or so ago, I was getting 10 degrees of KR for almost the whole pass. Now I am getting from zero to 2.5, so it's a lot better than it was then.

I was wondering if the filter is not allowing enough volume to flow, I might be running off the residual line pressure between the filter and the solenoids, for the first part of the run. Then running on a reduced flow for the rest of the run.

(since I had a slightly faster 60' time with the bigger jet, but a slower overall time...)
Also because it seems to hit harder now than it used to, but doesn't pull as hard down the track. The harder initial hit probably from the higher bottle pressure.

It would be real handy if I had a pressure gauge on the solenoid end of the line, and could see it while racing.

[Nachius]

Just as a note I'm here at home and the filter I'm planning on running is part number 15550NOS, but if you bypass yours and it corrects the problem I think I'll just sell this one even though its a pretty large filter!!

[John_D.]

I just looked at my receipt and that's the same part number I got. (I got mine locally, and it was $52, I probably could have ordered it cheaper, it was one of those impulse buys when I was getting some other fittings and stuff...)

It will probably be another month before I get back to the track... I have a couple of autocross events coming up and also a performance driving school and I'm going to a MECA event to benefit the Muscular Dystrophy Assocation (one of the guys in the local club has MD). It will be my first time at anything like MECA, not competing, just checking it out and probably contributing a little money. So this month is pretty well booked up!

[12secondv6]

70 jet.... how much of a shot is that?

When I had bigger injectors the car ran like a beast off the line and died top end.

Step by step with your car:

1) nitrous filter
2) bypass msd
lowering would hurt traction, not top end
3) 93 octane

[John_D.]

<blockquote>quote:</font><hr>Originally posted by 12secondv6:
70 jet.... how much of a shot is that?

Step by step with your car:

1) nitrous filter
2) bypass msd
3) 93 octane<hr></blockquote>

Thanks for the feedback.

I think the 70 is around 180 hp. :eek: :D
(if it was working correctly that is.) I will fall back to the 67 jet until I get this worked out, and then see.

1 and 2 were my thoughts too. And maybe the "old" medical-style NX bottle has a flow problem too. So hooking up my original blue NOS bottle fits in there somewhere too.

I probably had mostly 93 in the tank after all. I remembered that I kept putting topping off the tank with a few gallons of 93 at a time, for the last couple of weeks. For autocrossing. (since autocross likes a very full or very empty tank to minimize slosh in the slaloms)

I've seen the bigger dry shots on the LS1 cars use two nozzles. There may be something to that! One big jet may not flow as well as two smaller jets. I may try dual 47 jets at some point too.

[IronMan]

It's amazing how little nitrous flows w/ a clogged filter. Mine did not spray at all.

Maybe the filter you have is the problem. Also, rebuild the solenoids. I bet that as much nitrous you are pushing, they are getting worn out.

[12secdream]

JOHN, ditch that filter. i got rid of mine and the car ran much much better..

p.s... you know who this is ;)

[Tiago]

so are you running a 150 shot? :eek:

[John_D.]

I ran a 150 shot when I pulled the 13.2 time. That's the 67 jet.

I've run a bigger jet, the 70 jet, but since it wasn't flowing right, I don't consider that as actually running a bigger shot than the 150 yet... :D

[12secondv6]

180?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!!?

Holy crap man!!!!!!!


You have a HUGE set of steel balls!!!!!!


Please, please be carefull.

[John_D.]

<blockquote>quote:</font><hr>Originally posted by 12secondv6:
180?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!!?

Holy crap man!!!!!!!


You have a HUGE set of steel balls!!!!!!


Please, please be careful.<hr></blockquote>

nah, I just don't have much sense... [img]smile.gif[/img]


I am watching the a/f real close, and the knock retard. And the injector pulse widths. I think a 180 shot will be more than the injectors can handle. Running that jet was mainly a test to see where my restriction was. It's got to be that filter, or the old nx style bottle I tried this time.

(unless the filter screen at the solenoids got trash in it - but I installed the new big filter right after I ran the 13.2 and before I sprayed anymore, so I don't see how trash could get to the solenoids -- unless the filter is bad or had trash in the back side of it...)