I wanna check to see if I am correct.

I have done a few "spirited" runs at the track. I watched carefully as my gauges ran. I noticed two things: 1. The EGT just stays stuck on 1000F at the end of the run. 2. My FP is somewhere between 80-90psi under boost (damn half sweep gauge, can't tell exactly).

My question is this:

Am I running rich or lean?


P.S. Just for reference; I'm running a 70 shot and have the walbro 255 pump on the stock regulator with one step colder NGK plugs. Please just let me know what you think and why. Thanks in advance.

 

Hey Jaime
I started with an 80 shot at 80 psi and moved up to the 100 at 85 psi. EGT is pretty well the same for both settings, just under 1500. I run over 1000 just driving on the highway, not sure where you sensor is but mine is about 3" below the manifold. I would guess you are running rich but I haven't really played around enough with the fuel pressure to comment on how it affects power yet. I plan on doing that next time out though. I do check my plugs and they are not running lean, that is my biggest concern.
I am going to go back to a 70 shot and do some real fine tuning to see what I can run. Not sure I want to stay in the 13's, I hate wearing a helmet. I told Akrus it was a PITA and he figures I don't have it on properly if it is.
I would definately drop the pressure to the 70-75 range but keep a close eye on the EGT and check your plugs. Do it in stages though don't just drop to 70 in one shot. Flare jets are only $5. Don't scrimp.

 

My probe is right where both banks come together in front of the cat. I know that is going to yield slightly lower temps, but I didn't think that much. Running around at speed I am at 800-850F max. When I hit the bottle, it moves up to 1000F and that's it, it like gets there and stops. I haven't pulled out the plugs yet, as you suggested to run them down .004, but the plugs before that did not show any signs of either detonation or leaness (blue).

I suspected I was running rich. Doesn't that rob some HP? I noticed that up to about 3/4 track the car ran well, but towards the end it tended to just be there. Not really pulling like at the other end.

I will pull the plugs tonight and let you know what they look like. Let me get this straight, I have to increase the fuel jet size in order to lean it out? Let me know.

I'm trying to fine tune the 70 shot as much as I can before going to the track/or dyno again. I may just tweak to where I can and then do a full dyno run (with the O2 sensors hooked up) and see if I did it right or wrong.

 

I peak out about 1400F during a 1/4 run.

 

That's what I was thinking I should be. Maybe a little lower due to my probe being kinda further back. I didn't really want to put it on just one set of cylinders, but I know I'm going to be cooler since I'm further back.

How big a fuel jet do you think I would need to lean out (but not too much)? I know it's trial and error but I'm asking anyway.

 

What are your EGT's NA? I would try to keep them the same when your on the bottle. If you hit 1000F NA, then shoot for 1000F while spraying. Maybe your probe is in the wrong spot, maybe the guage is reading wrong, etc.

However, if you get the same temps NA and on the bottle, you can't be wrong.

 

Ok you mentioned before about where the probe was I forgot. Still it doesn't sound right going up to 1000 and staying there. Does it react fairly quickly going up and does it move down quickly after the run. There shouldn't be much lag, mine is almost instantaneous.
Yes running rich will certainly make you slower. Remember though you won't have as much on the top end, you have the same amount of nitrous going in from low rpm to high rpm so there is much more punch on the lower revs, thats normal, but I know what you mean I thought the same thing.
Oh, ya fuel jet, increase to reduce pressure, decrease to increase you have it right. I increased about 5 psi per 2 jet sizes but yours may be totally different have to try and see.

Jim

 

Yes it reacts quickly when either I go on the bottle or just go WOT N/A. I notice that the power comes on quickly and then when it shifts up into 3rd, the power seems to kinda dwindle to about N/A levels. Like I said, I watched the gauge both at the track and the dyno (dyno is easier since I can just watch the gauges and nothing else) and it seemed to do the same on both. Comes up to around 1000-1050F and it just stops. That is pretty much what it does N/A, except it does it a little slower from 800-1000F, but ends up basically the same. As a matter of fact if I remember correctly, N/A even goes a hair above that when held @WOT for a little bit.

I still think I may be a little on the rich side though. I want to try and lean it out a bit and see how that feels and go from there. I just don't think I'm tuned right.

Another question: What would make my ET's better? I see people with much slower 60' times and even 1/8 mi times with some pretty good ET's. What gives? Is it my reaction times? Should I try the deep/shallow stage better?

 

Well, that's what I was trying to do initially but everything I have read and researched basically says that on our cars I should be somewhere around 1400F to 1550F max. That's kinda riding on the edge, but If I could get mine to around 1250-1300F, I think I could be a little quicker and squeeze the most I can out of a 70 shot.

I'm trying to tweak on mine so I can decide whether to keep it where it's at and start working on something else (stereo) or am I going to go direct port or even bump up to 100 shot (which then would take more tweaking). I'm debating.

 

Jaime because of where you have the probe don't worry about the numbers. Just compare what it is N/A and on the bottle. That is whats important. I just wanted to make sure your gauge was working ok.
Reaction times are not counted into your 1/4 mile times, they are only used when you are racing against someone else to determine the winner. Don't even think about them unless you are in an actual elimination race, not even in time trials does it count into the time.
I would just start reducing my fuel pressure until you either hit the 70-75 psi range or until I see my EGT increasing, as long as you do that you should be ok. Also, keep an eye on the plugs.
If someone is getting a slower 60' and 1/8 than you and still get a faster 1/4 time and higher MPH then they have more HP because after the 60' and especially the 1/8 there is no wheelspin etc. If you are getting a good 60' you will get pretty close to the best et you can get for your car.
A lousy 60' and fast MPH indicates mucho wheelspin, not where you want to go.
I would also stay away from the deep staging, I have tried that and now I stick to as shallow as I can get and keep going starting sooner and sooner until you red light then you know the limit. I can hit .5xx all the time now during time trials but it takes a lot of concentration. Check my video it is a .530 or something, that is typical of my runs now. As soon as the eliminations start though, more tension and my reaction times go up to .6 or .7 but thats racing.
Get some flare jets and try reducing the pressure, I know what you mean about keeping an eye on it all going down the track though, its not as easy as it sounds. I keep trying to automate everything so its a no brainer but still keep forgetting something, gotta get a checklist like the pilots I guess.
Jim

 

That's the thing, I keep getting lousy 60' times because of wheel spin. I end up with good trap speeds (99mph so far) but lousy 2.4 60' times. I tried everything, but I just can't keep from spinning as soon as the juice hits in 1st or 2nd. I just need to keep practicing I guess. I wanna be in the 13's so bad I can taste it.

So, you think I should just lower my FP and see how it looks then? What fuel jet are you using? Just for reference.

 

Oh, ok I thought it was the other way around. If you don't have traction now you should see what its like with a 100 shot and slicks, all hell breaks loose and I spin all through first and half way through second and thats with VLSD. Get some drag radials or preferably slicks, forget what everyone says or most of them, I did and I run slicks. I can get a pretty good launch with my drag radials though as well. I have a set of Nitto 555R 205/45/15's, I got them because they lower the final drive ratio by 10% or so and get you much further into 3rd gear at the end of the quarter. My slicks are pretty much the same diameter though 22" vs 25" or so for the stock tire. The slicks were given to me after I bought the DR's, that why I have them. (Benevolent Son)
Also you might want to try launching at 1000 rpm vs torquing to 2k or whatever the convertor takes you too.

Fuel Jet I am using a .38 right now and I am getting 85 psi and when I was using the .42 I was getting around 80 psi. Not sure what you are using now but use yours as a reference not mine.
Not sure if I am helping or hindering Jaime but thats my .02.
Jim

 

Yep. I'm getting lousy 60's time because I am spinning as soon as I hit the bottle. I am also torque braking at 2-2500 rpms. So, you are saying to not do that. I guess you are saying that so that power comes on a little later and thereby not prone to wheel spin? I'll try it next time.

I'm going to try and get a hold of some jets to try this week and maybe even go to the dyno to try and hook everything up so he can tell me what's going on.

I am also running on almost bald Falken Zeix's 205/50/16's. I am going to try and get new rubber soon too to see if it will help. I am just frustrated because I've ran at the track twice now and the first time w/o a Y I was running 14.4's but I did have 2.2 60' times. Now w/a Y and VB mod I am running only 14.2's with 2.3-2.4 60' times. I know that the track was really bad on traction Fri. but geez I thought the Y and VB would help more than .2. Maybe it was the track's fault.