A/F experts inside please????????
Thread Starter
Racer
Joined: Jul 2005
Posts: 290
Likes: 0
A/F experts inside please????????
Here is a graph from my most recent dyno with a 170hp shot of nitrous. The spray comes on at 3000rpms.
I took just the A/F from the dyno graph and focused on that alone. Check out the attached graph and tell me what you think? I don't think that is good. From what I've heard, a lean spike happens with a wet kit. But check out how high it spikes? Kind of scary!! I'm not spraying anymore till I get this figured out.
I think I need to get a hold of TJ again and have him do some major tuning. Is this kind of spike normal for wet kits? That seems like an aweful high lean spike.
I need some major help!! Not the mental kind Ellis
Graphs:
http://i33.photobucket.com/albums/d5...e/DSC04331.jpg
http://i33.photobucket.com/albums/d5...e/DSC04329.jpg
Close up of the Graph:
http://i33.photobucket.com/albums/d5...e/DSC04328.jpg
I took just the A/F from the dyno graph and focused on that alone. Check out the attached graph and tell me what you think? I don't think that is good. From what I've heard, a lean spike happens with a wet kit. But check out how high it spikes? Kind of scary!! I'm not spraying anymore till I get this figured out.
I think I need to get a hold of TJ again and have him do some major tuning. Is this kind of spike normal for wet kits? That seems like an aweful high lean spike.
I need some major help!! Not the mental kind Ellis
Graphs:
http://i33.photobucket.com/albums/d5...e/DSC04331.jpg
http://i33.photobucket.com/albums/d5...e/DSC04329.jpg
Close up of the Graph:
http://i33.photobucket.com/albums/d5...e/DSC04328.jpg
Last edited by 00'Vette; Mar 19, 2007 at 10:37 PM.
Le Mans Master
Joined: Aug 2005
Posts: 5,375
Likes: 328
From: CA.
St. Jude Donor '13-'14-'15
I had a similar problem with my NOS system on a wet kit '98 C5(A4)
After viewing the logged files it had a nasty lean spike at the initial hit (4200) & like yours maybe 1 more time further down a brief spike.
What I found it to be was that my fuel line on my solenoid has air in it and momemtarily at the start til the air bleeds off it was lean--then soon after- a bubble of air made the logged file show another spot of lean again---So I now purge the fuel lines as well as the NOS lines before i use it--Especially when it's been sitting unused for awhile--After purging the fuel its OK for a long time until it sits overnight for a couple days---I just use a jumper wire while its running and touch the battery + terminal to the hot terminal on the relay-You can hear the engine amost die then you know it's bled---Make sure you don't touch the NOS solenoid or activate it somehow
Its not a perfect solution but OK for now--I probably will install a check valve or some kind of air relief valve later on.Purge yours and see if the spikes go away---Oh yeah---This cleared up mine perfectly.
After viewing the logged files it had a nasty lean spike at the initial hit (4200) & like yours maybe 1 more time further down a brief spike.
What I found it to be was that my fuel line on my solenoid has air in it and momemtarily at the start til the air bleeds off it was lean--then soon after- a bubble of air made the logged file show another spot of lean again---So I now purge the fuel lines as well as the NOS lines before i use it--Especially when it's been sitting unused for awhile--After purging the fuel its OK for a long time until it sits overnight for a couple days---I just use a jumper wire while its running and touch the battery + terminal to the hot terminal on the relay-You can hear the engine amost die then you know it's bled---Make sure you don't touch the NOS solenoid or activate it somehow
Its not a perfect solution but OK for now--I probably will install a check valve or some kind of air relief valve later on.Purge yours and see if the spikes go away---Oh yeah---This cleared up mine perfectly.
Drifting
Joined: Sep 2005
Posts: 1,258
Likes: 0
From: Home Southern Maine
St. Jude Donor '08
So I now purge the fuel lines as well as the NOS lines before i use it--Especially when it's been sitting unused for awhile--After purging the fuel its OK for a long time until it sits overnight for a couple days---I just use a jumper wire while its running and touch the battery + terminal to the hot terminal on the relay-You can hear the engine amost die then you know it's bled---Make sure you don't touch the NOS solenoid or activate it somehow
Its not a perfect solution but OK for now--I probably will install a check valve or some kind of air relief valve later on.Purge yours and see if the spikes go away---Oh yeah---This cleared up mine perfectly.
Its not a perfect solution but OK for now--I probably will install a check valve or some kind of air relief valve later on.Purge yours and see if the spikes go away---Oh yeah---This cleared up mine perfectly.
Never would have guessed that!
That's a great tip!
Drifting
Joined: Sep 2005
Posts: 1,258
Likes: 0
From: Home Southern Maine
St. Jude Donor '08
Goin to the dyno Saturday wx Permiting...
Here is a 150 shot from last year
Or course the air was out by then as we did a 50 then a 100 prior...
Here is the 50 that may have had an air bubble
Last edited by Beer99C5@FastbirdPerf.com; Mar 20, 2007 at 02:07 PM.
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Le Mans Master
Joined: Aug 2005
Posts: 5,375
Likes: 328
From: CA.
St. Jude Donor '13-'14-'15
YES mine did pop into the 15's too---I was very concerned-It lasts for less than a full second and i don't really know if that's long enough to cause any damage-but I didn't want to take any chances
Thread Starter
Racer
Joined: Jul 2005
Posts: 290
Likes: 0
Thanks guys!! I'd like to see what a normal wet kit lean spike is via multiple dyno graphs.
I think I'm going to start a thread about it.
Beer, could you maybe ask your tuner when he's dynoing your car what he would consider a safe lean spike? I've tried to get a response via PM's from Dave (nitrous outlet) over at LS1tech, but I can't get to him.
I'm sure he'd have great info on this subject.
I think I'm going to start a thread about it.
Beer, could you maybe ask your tuner when he's dynoing your car what he would consider a safe lean spike? I've tried to get a response via PM's from Dave (nitrous outlet) over at LS1tech, but I can't get to him.
I'm sure he'd have great info on this subject.
Melting Slicks
Joined: Jul 2005
Posts: 2,586
Likes: 2
From: Bardstown Kentucky
I had this same problem and found that simply not purging my NOS fixed it... It allowed the fuel to spray before the NOS and had no lean spots. Although there was a slight rich spot but not for very long.
Thread Starter
Racer
Joined: Jul 2005
Posts: 290
Likes: 0
I'm going to try and move my fuel noid right next to the nitrous plate so I can put a really short fuel line between the noid and plate. I'm assuming it'll make a difference, but with a spike as high as mine is for as long as it stays lean..........do you think it'll be worth the effort.
How lean do you typically see wet kits go (that is acceptable)?
Pro
Joined: Feb 2007
Posts: 702
Likes: 1
From: Frankfort Il
Right, but does my A/F graph look odd to you? I'd like a tuner's opinion.
I'm going to try and move my fuel noid right next to the nitrous plate so I can put a really short fuel line between the noid and plate. I'm assuming it'll make a difference, but with a spike as high as mine is for as long as it stays lean..........do you think it'll be worth the effort.
How lean do you typically see wet kits go (that is acceptable)?
I'm going to try and move my fuel noid right next to the nitrous plate so I can put a really short fuel line between the noid and plate. I'm assuming it'll make a difference, but with a spike as high as mine is for as long as it stays lean..........do you think it'll be worth the effort.
How lean do you typically see wet kits go (that is acceptable)?
Thread Starter
Racer
Joined: Jul 2005
Posts: 290
Likes: 0
We use a Mustang Dyno, and because of the loading it does look different than what I usually see. Typically we have a very sharp lean spike as opposed to your more gradual slope. Then after it reaches the peak, it falls off a little quicker than what yours is. I wouldnt say anything's neccessarily wrong, it's just different from what I see on my dyno. Shortening the fuel line from the selinoid to the nozzel should help as well.
1st Gear
Joined: Jan 2007
Posts: 1
Likes: 0
I fixed the lean spike on my last car by doing something a bit unorthodox. I used a FPSS, but I T'd it in behind the fuel solenoid between the solenoid and the nozzle. This way there had to be FP in the line to the nozzle before the nitrous solenoid would open. Ended up giving a rich spike to 10.5 or so that we could mostly tune out to around 11.5 after some playing around. Made me feel alot better about the whole thing.
