Login    Forum    Search    FAQ

Board index » Racing Forum » General Topics




Post new topic Reply to topic  [ 32 posts ]  Go to page Previous  1, 2, 3  Next
Author Message
 Post Posted: Sun May 20, 2012 6:53 pm 
Offline
User avatar

Joined: Wed Apr 19, 2006 8:20 pm
Posts: 5852
Location: N.J.
shrinker wrote:
My carbys dont vary from the dyno to the race track. Either holleys or smartcarbys, it doesnt matter. This is a long way out, something must be causing that.



Of course there must be something wrong with his engine or his carb :- ...

_________________
Image
running E85
Best ET 8.07
Best MPH 170.71
Barry


Top 
 Profile  
 
 Post Posted: Sun May 20, 2012 7:09 pm 
Offline
User avatar

Joined: Sat Feb 07, 2009 4:12 pm
Posts: 1215
Location: Adelaide Australia
I remember people and the flutes etc, but this is a BIG change from a dyno. To be running the AFR stated is dangerous and not normal from a dyno to the track. A small change I can accept but not this much. Id bet its not the carby doing it either. The Lambda calibration on whatever logger he has needs to be checked, the plugs need to be checked to find out if its believable. when the jets were richened it went slower, that doesnt make sense unless the readings are wrong or something is wierd.


Top 
 Profile  
 
 Post Posted: Sun May 20, 2012 7:18 pm 
Offline
User avatar

Joined: Wed Apr 19, 2006 4:11 pm
Posts: 2749
Location: Shepherdsville, KY
I didn't have any AFR on the dyno. He tunes with EGTs and BSFC. I know I was told on this board that you can't do that but this guy wasn't going for any specific numbers but how those numbers were affected by changes that were made. That and we were reading the plugs. I didn't improve my ET any by changing jets but I wasn't hitting the shift points right and wasn't making any consistent passes. That makes it hard to determine what the jet change was doing. I will try to get to the track for some testing and once I start driving this thing right I will try to do a little tuning.

Edit: I do think I need to check the validity of my AFRs with the logger. I do free air cal. on them periodically and it was done when I finished putting the engine in the car but there may be a problem with the calibration or maybe the location of the sensors.

_________________
Chuck Woloch

Chuck's Automotive
Full line Computech dealer
chucksautomotive@yahoo.com
Image


Top 
 Profile  
 
 Post Posted: Sun May 20, 2012 7:27 pm 
Offline
User avatar

Joined: Sat Feb 07, 2009 4:12 pm
Posts: 1215
Location: Adelaide Australia
I remember your dyno sessions, the BSFC's and EGT's were nothing unusual meaning your AFR were in the right place. Even tuning on a dyno from BSFC and EGT's can reveal if a tune is in the ball park, the dyno guy would have picked up if its too lean. Its too lean on the track if its a true reading. The plugs tell the truth. If there is tan on them thats a reasonable darkness then its safe and something is wrong with the readings. The motor is making mumbo but when you changed the jets, even if you missed the shift points, you as the driver, should be able to feel it pull harder by enriching it. It should pick up a noticeable feel of power if it was truly 15:1 when you richen it.
I just cant believe that you ran it on a dyno without figuring it to be too lean or you get this much change in AFR going to the track. Something doesnt add up.


Top 
 Profile  
 
 Post Posted: Sun May 20, 2012 8:50 pm 
Offline
Site Admin
User avatar

Joined: Tue Apr 18, 2006 6:38 am
Posts: 11804
Location: Coming At Ya!
All good info under certain conditions shrinker but I digress on some of these issues! When you're making THAT much more power with a NEW combo, the driver is the biggest liar in the bunch!! (No offense Chuck) It's just that you CANNOT think and store info as fast as it's happening on a run! I've been there and done that from the driver's seat, ie, Camaro @ 5.47 to Dragster @ 4.95 and I didn't have a clue! Only a half second you say?.......... :-

We need to back off and let Chuck get "acquainted" with his new engine!!! After all, this "Ain't His Fist Rodeo" and he's seen that richening it up slowed it down so he's got something to work with! After he's done that, then some of us may be able to help him tweak it but right now, even HE doesn't have a clue! I'd run it where it was dynoed until he's comfortable with it.

And I'll leave you with this one question. Shrinker, when was the last time YOU made a 7 second quarter mile run in your car @ over 170 MPH?? O:)

_________________
Big Boyz Toyz!

Image

Necessity is the plea for every infringement of human freedom. It is the argument of tyrants; it is the creed of slaves.

William Pitt, British Prime-Minister (1759-1806)


Top 
 Profile  
 
 Post Posted: Sun May 20, 2012 10:29 pm 
Offline
User avatar

Joined: Sat Feb 07, 2009 4:12 pm
Posts: 1215
Location: Adelaide Australia
Ken0069 wrote:

And I'll leave you with this one question. Shrinker, when was the last time YOU made a 7 second quarter mile run in your car @ over 170 MPH?? O:)

The answer to that question is I dont drive the car but the driver can tell when I do a small change. So I expect others to as well. Our car runs 8.19 and 169.96mph

What I'm saying about Chucks car is to make sure that the engine is not running at 15:1 AFR. Look at all the signs, make dam sure it running richer than that. If its got the same sparkplug signs, some exhaust ports etc as the dyno then believe its OK. If not, then fix something before you have nothing to fix. I'm just trying to be helpful not hindering.


Top 
 Profile  
 
 Post Posted: Sun May 20, 2012 11:25 pm 
Offline
Moderator
User avatar

Joined: Tue Apr 18, 2006 3:20 pm
Posts: 1457
Location: Missouri
In my experience when you go two jets down on all 4 from best power jetting will be significantly down on power from max pwr. I went down two on my Camaro once and when I went up on the converter it was about 200-300rpm less stall ... it takes a lot of difference in power to change that much stall. Go up two jets from best pwr and it'll be off a little but not nearly as much as two jets lean.

I'm with Ken on not trusting the driver's feedback. There are so many things you're doing, feeling, seeing and hearing. I know I can't remember or even accurately feel all of what is going on. We don't process data fast enough. If you have been running the same combo for a long time you might be able to tell the difference in some things. I can usually feel if my 60' is a good one or not. Judging the pull in the middle or mph is nearly impossible. Trust a data recorder not a driver.

My guess is the O2 is reading wrong or the change would have been big when going up two jets.

Rick


Top 
 Profile  
 
 Post Posted: Sun May 20, 2012 11:30 pm 
Offline
User avatar

Joined: Sat Feb 07, 2009 4:12 pm
Posts: 1215
Location: Adelaide Australia
15:1AFR is 4 jet sizes too lean. I'm being serious. It can run that AFR if the fuel octane is enough BUT it will damage the engine if thats the true AFR ---it needs to be checked before racing again in my opinion. I would certainly be placing that issue at the top of my maintenance list before the engine was loaded again.


Top 
 Profile  
 
 Post Posted: Sun May 20, 2012 11:34 pm 
Offline
User avatar

Joined: Sat Feb 07, 2009 4:12 pm
Posts: 1215
Location: Adelaide Australia
Before anyone goes "how can it damage the engine if the octane is enough?" It does so by the heating of the oxygen, thats got nothing to do with the fuel octane. The hot oxygen from the high temp of a stoich burn (because thats what its reading) will damage the engine. its not detonation its oxidation.


Top 
 Profile  
 
 Post Posted: Mon May 21, 2012 5:16 am 
Offline
User avatar

Joined: Wed Apr 19, 2006 8:20 pm
Posts: 5852
Location: N.J.
Remember also that Chuck is doing all the gear changes and sure he is concentrating mostly on that
I would think but not sure as my car shifts it self...

Chuck, My original O2's were still calibrating good in free air but they had also of time on them. What I had noticed it that they were reading about the same as yours but my EGT's were in the ball park of 1350/1380......So I went ahead and picked up a couple and swapped them and the reading came down.......In short I would just replace them and see if they make a change like mine did.. ;-)

_________________
Image
running E85
Best ET 8.07
Best MPH 170.71
Barry


Top 
 Profile  
 
 Post Posted: Mon May 21, 2012 9:47 am 
Offline
Site Admin
User avatar

Joined: Tue Apr 18, 2006 6:38 am
Posts: 11804
Location: Coming At Ya!
Hey Chuck. Sorry for hijacking your thread last night but I just couldn't resist "messin" with shrinker a bit! ;-)

I'm going to "assume" that you're running the same induction setup, ie, scoop, carb air pan etc so if that was all sorted out and it was working before, it should work now with exception of some minor carb tuning stuff.

I think when you went up on the jet and it slowed down that much it pretty much told you what it didn't like. Having said that, a little phat is better than a little lean until you can get your sensor issues straightened out or get a good plug read.

Which brings me to O2 sensor life on leaded race gas?? If memory serves, I've seen written somewhere that sensor life is only about 15 hours in a well tuned engine and please, someone correct me if that number is wrong? I also read where overly rich engines will kill them even quicker. I've got one that I've run for a long time, in fact I think it's the original one I got with my system? But then again, I run methanol "most" of the time and I don't believe that fuel has much of a negative effect on them.

Ennywho, it'll come around. It just takes time. ;-)

_________________
Big Boyz Toyz!

Image

Necessity is the plea for every infringement of human freedom. It is the argument of tyrants; it is the creed of slaves.

William Pitt, British Prime-Minister (1759-1806)


Top 
 Profile  
 
 Post Posted: Mon May 21, 2012 10:09 am 
Offline
User avatar

Joined: Wed Apr 19, 2006 4:11 pm
Posts: 2749
Location: Shepherdsville, KY
I'll probably throw a couple new sensors in it and give it a try. I think these were new last year and I leave them so they probably are too old. I was thinking they were only good for about 10 hours on leaded fuel and I'm sure overly-rich will take them out sooner. Any contaminants will reduce the life of them such as oil and the wrong type of silicone. I should have thought of that because I know in my experience in dealing with the computer controlled fuel systems on production vehicles as the O2 ages and degrades it will report a leaner than actual fuel condition back to the engine control computer. This usually results in poorer fuel economy as the engine computer will compensate by adding fuel until the reported mixture is what it wants and that's why the front O2 sensors on modern fuel injected vehicles should be replaced at least every 100K miles. I just thought that if the sensors were bad there wouldn't be enough adjustment for the free air calibration. Thanks for the tip Barry.

I just checked my records and those O2s were new at the beginning of the 2010 race season so they have 2 full seasons on them. That would be at least 160 runs and if it averages 5 minutes per run that's over 13 hours not counting warm up and break in. Yeah, I think it's due for a couple.

_________________
Chuck Woloch

Chuck's Automotive
Full line Computech dealer
chucksautomotive@yahoo.com
Image


Top 
 Profile  
 
 Post Posted: Mon May 21, 2012 11:36 am 
Offline
User avatar

Joined: Wed Apr 19, 2006 4:11 pm
Posts: 2749
Location: Shepherdsville, KY
I just dug up the instructions for the free air calibration. Looks like I did it wrong. Lesson of the day: don't trust what you think you know :- I'll try this with the FAC done properly but I picked up a couple of new sensors just in case. I will eventually use them anyway.

_________________
Chuck Woloch

Chuck's Automotive
Full line Computech dealer
chucksautomotive@yahoo.com
Image


Top 
 Profile  
 
 Post Posted: Sat May 26, 2012 11:01 am 
Offline
User avatar

Joined: Wed Apr 19, 2006 4:11 pm
Posts: 2749
Location: Shepherdsville, KY
I tested at US60 last night. When I got there the sun was still up and the D.A was a little over 3,200'. I was next up for the burnout when I noticed little to no oil pressure =P~ . I shut it off and scrolled the display for my logger to oil pressure and cranked it back up. It had plenty and the pro lite was going out as soon as it started. I figured I would drive it back to the trailer but Eddy saw something leaking under the car and when we pushed it back I could see it was oil. We pushed it back to the trailer where I found the sender for my OP gauge had failed. Because I had the prolite and OP on the data logger I just plugged it off and took it to the line. 1st pass it went 5.25 @ 131 MPH with a 1.153 60'. I found the shift points but it might do a little better if i got into 2nd a little sooner. I left everything like it was and made a 2nd pass to get a good baseline. That time the sun was off the track and the air improved a little and it went 5.205 @ 132.05 with a 1.139 60'. I felt that was a solid run so I figured I would step the jets down a little. I had previously jetted up a total of 5 sizes from the dyno so I dropped them down 2 sizes. The air improved a little for that run too but it spun the tires a little to run 5.217 @ 132.03 with a 1.143 60'. It had been a while since I had swapped the slicks so I flipped them around and left everything else the same for the next shot. It went 5.207 @ 132.04 with a 1.135 60'. I was so close to running a teen I didn't want to stop but it was getting late and I figured I had done what I came to do. I will jet it back up plus a couple for the next race and see what happens. The AFRs had improved a little with the correct FOC and it still looks a little lean. I had it up to 89 w/PV and 99 and dropped it to 87 & 97. The MPH didn't change with the jet change so it probably is still a little lean. I'm thinking maybe I need to adjust the floats up some and maybe because of the multiple hits on a stick car the fuel in the bowls is a little less stable?

I was all loaded up and ready to go when I saw Jody (us7race) was still in for the final in the no-box class, so I waited for the final. Congrats Jody! His 2nd win in a row. I think he's going for the gold card for next year too.

I got about 2 miles from my exit on the way home when one of the rear trailer tires blew out. I just turned on the blinkers and dropped to 45 MPH for the rest of the trip. Too close to home to change a trailer tire. And before Ken gets on me for the speed with the trailer tires I was only going about 70 (the limit) and had kept the speed down for the entire trip. I had put 4 LR Es on it last year and this was one of the Ds that failed. I guess next week I'll get a couple more Es for it.

_________________
Chuck Woloch

Chuck's Automotive
Full line Computech dealer
chucksautomotive@yahoo.com
Image


Top 
 Profile  
 
 Post Posted: Sat May 26, 2012 4:09 pm 
Offline
User avatar

Joined: Wed Apr 19, 2006 6:43 am
Posts: 1980
Location: Tell City, IN
Sorry to hear about the trailer tire Chuck that sucks.. [-(
Your car looked good leaving and was hauling the mail..
I believe there is some 5.0's in it in good air. \:D/

_________________
6.11@110 Gas
1.3718 Sixty Foot with the rear wheels Gas

6.07@110 on Alcohol Injection with a 4-link 4-6-12
Best 60' 1.2537 Alcohol Injection 4-29-11
Thru the Mufflers!!


Top 
 Profile  
 
Display posts from previous:  Sort by  
 
Post new topic Reply to topic  [ 32 posts ]  Go to page Previous  1, 2, 3  Next

Board index » Racing Forum » General Topics


Who is online

Users browsing this forum: No registered users and 1 guest

 
 

 
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Search for:
Jump to:  
cron