I was pleased BUT when i step on it and get to WOT It boggs and then goes like 1 second later. I am using the NOS TBI plate systemwith 100 shot jets. What do you guys think the matter is. I have the timing set at zero now. And let me tell you this car is a total DOG with no timing advance. It feels like a 16 second car now without spray. It was at 6* advanced before. But on spray it feels like a high 12 sec car. I need help with the bogging part. I did a full tune up last night and a fuel filter. Maybe switching to a bit smaller jet on the fuel side would help? Im open to any suggtestions. I was thinking of putting 4* advance back in it because i heard no detonation whatsoever on 89 pump gas. I will run 93 next time. Man this thing flies after it boggs. If i could get the bog out it would go high 12s for sure.

 

sounds like you are pig rich, yeah, maybe try leaning it out a bit. Do you have anyway of monitoring your a/f ratio?

 

pull a spark plug out. Thats pretty much it.

 

I would want to make absolutely certain it is actually rich before leaning out. Remember- an engine can run rich all day long, but it will only run lean one time!

 

oh i know. I am at work right now so ill go home tonight and pull a plug or 2. If it is rich ill lean her out. I also bumped up the fuel pressure maybe thats the problem running with jets set for stock fuel pressure.

 

I wanna c times

 

me too but it will be a while due to the cost of filling the bottle and entry fee. Give ma around 2 weeks for some times.

 

Have you pulled a plug after a nitrous pass? The proper way to test it, is to make a run in 3rd gear at WOT (with an automatic car) to where you want to ideally run it up to, and then kill the engine. Shut it off.

Pull a plug out after its cooled off and check for a timing mark. It should be visible on the electrode of your spark plug. The closer to the "curve" of the electrode it is, the closer you are on timing.

Its best to use this method to dial in your timing and also best to perform this check with a new set of plugs as the timing mark will move around with everyday driving on it and get lost. The reasoning for shutting it off at full throttle is that it will be where you are making your peak power.

If anyone else has anything they would like to add, go ahead.

As for it being rich, check how it looks when you pull the plug. If its light brown you are good.

 

the worry with looking at the plugs, is that it gives you no idea what the AFR is doing at the point of the bog. It does sound rich though.

 

Dewey is right. It would be awesome if you could get some kind of wide band O2 on there or some type of datalogging software like Diacom that will record your o2 millivolts.

 

u still running the stock fuel pump?

 

Do you have a Purge? I ran a 125 shot on a newer style Gmc Jimmy and I had to purge to get the bog to go away. I didnt have this problem on my 66 Vw bug with a 40 shot, but its also a smaller amount of nitrous. If you dont have a purge, When doing a burnout before a race you can activate the nitrous for a second or two to purge the lines and see if that helps, it always did for me.

 

Hey Guido I think I am missing the "curve" part. Can you break it down into more layman terms??? Also by having the mark closer to the curve does it mean that spark is not too hot or cold or that it is sparking at the correct point for proper combustion???? Any info is good, I am just trying to pick up some knowledge on reading plugs as I run a 100 shot as well and am happy with my track times but I still want to be able to run a 150 before the season is over. Also typically what gains are noticed by going from a 100 to a 150???? If I could grab another 4 tenths I would be pretty happy.

 

yes stock fuel pump

no, no purge i had a 75 shot on my 1996 S-10 and i never had to purge it.

Never got around to pull a plug last night. My grandmother came over last night for dinner. I will be doing this tonight though. Ill let you all know and if this comes out alright ill do the timing thing that guido was talking about.

 

ok pulled a plug last night and it is wayyy to rich. It even smelled rich on the plug. Plug was black. Anyways i put 4* advance back in it and didnt drive it today due to going out of town. Anyways when i get back i will be filling my bottle, puting a flowmaster on, and trying that out. I will also be puting the fuel pressure back to stock for the correct jet size on the fuel side of the nitrous. It should run alot better. I hope

 

I cant make it much simpler. LOL I meant it when I said, the curve.

Around the curve of this part

 

i think he and i want to know which mark you are talking about.

 

I think he means look for the color change point on this thingy.

 

I understand the color change and I know what even slight detonation looks like a mile away. I was just wanted to know more about finding your ideal total timing from looking at the spark markings from the electrode. I just wasn't sure what "curve" Guido was referring to. There are two electrodes on a plug, the center electrode and the ground electrode. I think he was referring to the ground electrode. Does he mean the spark markings will be closer to the base of the ground electrode where it attaches to the plug??? How does more or less timing affect where the spark jumps??? I thought (my first mistake ) that spark will take the path of least resistance???

 

To be honest, this is new to me also. I'm ready to learn more as well.

 

Yea, I’ll chime in on the “I sorta know what you’re talking about but not really camp.” To be honest, I don’t think I’ve ever heard anything about reading plugs to determine timing, but I’m willing to play with it if I knew what I was looking for.

I’m assuming that you mean the curve on the electrode, but what do you mean by “timing mark?” Discoloration? Where the deposits end (like in your pic)?

Which way does it move when the timing is early/late?