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Struggling, any idea why first run of day so far off??? #347716
06/15/09 11:30 AM 06/15/09 11:30 AM
Joined: Sep 2003
Posts: 481
Cheswick, PA
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Bob_Spelic Offline OP
mopar
Bob_Spelic  Offline OP
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Cheswick, PA
So why does my first run of the day appear so far off? I get the water temp to 140 driving around the pits. I stand on it pretty hard whenever possible while warming it up. I also jacked it up about 10 minutes beofoe its time to run and I run it to 160 on the jack stands, forward and reverse on the trans and hold the car on the trans brake at 4000 RPM for about 15 seconds?

It appears to be quicker everywhere except the 60 ft, so I’m thinking its just making more HP, but why?

Any ideas as to what may cause this?

Here are this week’s runs;

60ft 1/8 mile 1000 ¼ mile

1.19 5.42 126 7.12 8.57 156
1.18 5.35 128 7.01 8.43 159
1.19 5.36 128 7.02 8.43 160
1.19 5.33 130 6.99 8.40 159
1.20 5.34 129 6.99 8.39 160
1.18 5.31 130 6.94 8.36 154
1.18 5.31 130 6.95 8.35 161
1.18 5.31 130 6.95 8.35 160
1.18 5.31 130 6.95 8.37 152

And last weeks:

1.19 5.40 126 7.10 8.56 154
1.19 5.37 127 7.05 8.49 155
1.20 5.38 127 7.06 8.49 156
1.19 5.37 127 7.05 8.48 156
1.19 5.39 126 7.09 8.55 155
1.18 5.37 127 7.06 8.50 156

And at Byron (so track doesn’t matter)

1.18 5.36 126 7.05 8.49 156
1.18 5.29 129 6.94 8.35 159
1.20 5.33 129 6.99 8.40 158
1.21 5.34 129 6.99 8.41 158
1.18 5.32 128 6.99 8.42 157
1.19 5.35 127 7.02 8.46 151
1.20 5.30 129 7.00 8.38 154

Bob Spelic
Re: Struggling, any idea why first run of day so far off??? [Re: Bob_Spelic] #347717
06/15/09 11:34 AM 06/15/09 11:34 AM
Joined: Nov 2003
Posts: 6,293
Rock Springs
Bob_Coomer Offline
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Bob_Coomer  Offline
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Posts: 6,293
Rock Springs
Quote:

So why does my first run of the day appear so far off? I get the water temp to 140 driving around the pits. I stand on it pretty hard whenever possible while warming it up. I also jacked it up about 10 minutes beofoe its time to run and I run it to 160 on the jack stands, forward and reverse on the trans and hold the car on the trans brake at 4000 RPM for about 15 seconds?

It appears to be quicker everywhere except the 60 ft, so I’m thinking its just making more HP, but why?

Any ideas as to what may cause this?

Here are this week’s runs;

60ft 1/8 mile 1000 ¼ mile

1.19 5.42 126 7.12 8.57 156
1.18 5.35 128 7.01 8.43 159
1.19 5.36 128 7.02 8.43 160
1.19 5.33 130 6.99 8.40 159
1.20 5.34 129 6.99 8.39 160
1.18 5.31 130 6.94 8.36 154
1.18 5.31 130 6.95 8.35 161
1.18 5.31 130 6.95 8.35 160
1.18 5.31 130 6.95 8.37 152

And last weeks:

1.19 5.40 126 7.10 8.56 154
1.19 5.37 127 7.05 8.49 155
1.20 5.38 127 7.06 8.49 156
1.19 5.37 127 7.05 8.48 156
1.19 5.39 126 7.09 8.55 155
1.18 5.37 127 7.06 8.50 156

And at Byron (so track doesn’t matter)

1.18 5.36 126 7.05 8.49 156
1.18 5.29 129 6.94 8.35 159
1.20 5.33 129 6.99 8.40 158
1.21 5.34 129 6.99 8.41 158
1.18 5.32 128 6.99 8.42 157
1.19 5.35 127 7.02 8.46 151
1.20 5.30 129 7.00 8.38 154

Bob Spelic


Looks like you have a nice running car thats for sure...anyways
I find that normal with these old Mopars. I dont know why either, but about every car I have built and raced picks up after the first time trial. Usually about the same as your seeing, up to a tenth, usually 5+ numbers anyways.

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Re: Struggling, any idea why first run of day so far off??? [Re: Bob_Coomer] #347718
06/15/09 11:41 AM 06/15/09 11:41 AM
Joined: Dec 2006
Posts: 1,178
Indy
FlyFish Offline
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Indy
Mine does that too (picks up a close to a 10th after the first run of the day). I thought it might be due to the trans fluid not being up to temp, but if you're holding the trans brake for 15 seconds then you should have a LOT of heat in there.

67 Barracuda street car, 408, e85, 1.38 60', 6.44 @105.9 in the 1/8 mile, 10.19 @130.5 in the 1/4...so far....
Re: Struggling, any idea why first run of day so far off??? [Re: Bob_Spelic] #347719
06/15/09 11:44 AM 06/15/09 11:44 AM
Joined: Jan 2003
Posts: 19,363
Las Vegas
Al_Alguire Offline
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Las Vegas
Do you have any weather Data from those runs? Might check your tune up if the DA is going up and you are going faster. If the DA is going down, as in you race at night T&T in the evening/day then it makes sense to me.

"I am not ashamed to confess I am ignorant of what I do not know."

"It's never wrong to do the right thing"
Re: Struggling, any idea why first run of day so far off??? [Re: FlyFish] #347720
06/15/09 11:44 AM 06/15/09 11:44 AM
Joined: Jan 2003
Posts: 32,394
Q
Quicktree Offline
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everybody does it, not just mopars. usually the track has a lot to do with it.
Re: Struggling, any idea why first run of day so far off??? [Re: FlyFish] #347721
06/15/09 11:47 AM 06/15/09 11:47 AM
Joined: Jan 2003
Posts: 2,533
Alexandria, LA
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Blucuda413 Offline
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Alexandria, LA
15 seconds sure sounds like a long time. Your trans temp must be way up after that. Could that have something to do with it??
Re: Struggling, any idea why first run of day so far off??? [Re: Blucuda413] #347722
06/15/09 01:47 PM 06/15/09 01:47 PM
Joined: Sep 2003
Posts: 481
Cheswick, PA
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Bob_Spelic Offline OP
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Cheswick, PA
The DA changes between the first and second runs listed above was only moving about 400 feet. I ruled that out. Maybe .01 or .02 of the .140 variation at most. The 60 ft times did not move more than .01 all day.

I stand on the trans brake and then let the whole mess cool down for at least 15 minutes before going into the lanes.

Can't seem to find what it needs to run the number the first run. After 2 rounds it's dead solid and predictable.

Keep ideas coming if you can. I am at wits end with it!

bob spelic
Re: Struggling, any idea why first run of day so far off??? [Re: Bob_Spelic] #347723
06/15/09 01:55 PM 06/15/09 01:55 PM
Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY Offline
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Romeo MI
I think alot of it is it finally gets a good heat
soak after the first run(rearend, trans and engine)
Re: Struggling, any idea why first run of day so far off??? [Re: MR_P_BODY] #347724
06/15/09 02:05 PM 06/15/09 02:05 PM
Joined: Mar 2007
Posts: 3,300
Northern Indiana
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An old friend of mine used to warm his car up,then swap in fresh plugs before his first pass.He swore if he did'nt,the first pass was worthless.He had a VERY good running car,just something you could try.

www.dunnuckracing.com
Re: Struggling, any idea why first run of day so far off??? [Re: Blucuda413] #347725
06/15/09 02:09 PM 06/15/09 02:09 PM
Joined: Jan 2004
Posts: 4,866
North of Detroit
HemiDart68 Offline
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Quote:

15 seconds sure sounds like a long time. Your trans temp must be way up after that. Could that have something to do with it??



My trans guy told me that when your on the brake, it raises trans temps like 20 degrees a second or something wild like that. I think you might be putting way too much heat into your stuff by doing that.

In God we trust, all others pay cash. www.lightnens.com (Home of the world's fastest Paint Job)
Re: Struggling, any idea why first run of day so far off??? [Re: Bob_Spelic] #347726
06/15/09 02:20 PM 06/15/09 02:20 PM
Joined: Jan 2003
Posts: 5,875
communist bloc of new jersey
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jamesc Offline
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not that it helps answer your questions but i don't bother warming the driveline anymore. i'll warm the car just sitting there at idle while i'm getting stuff outta the trailer (suit, helmet, etc.). i make sure it's at least 160° before staging. my car will move from the first to second pass but not like the numbers you're posting.

Re: Struggling, any idea why first run of day so far off??? [Re: jamesc] #347727
06/15/09 02:46 PM 06/15/09 02:46 PM
Joined: Nov 2003
Posts: 7,348
Mt.Vernon ,Ohio
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My is also slow first run..by 3 anyhow ..I just know it and live with .. I am pretty sure it is trans temp..Get on the converter a little before you pull up on the track..
Re: Struggling, any idea why first run of day so far off??? [Re: jamesc] #347728
06/15/09 02:54 PM 06/15/09 02:54 PM
Joined: Jun 2009
Posts: 644
Minnesota
Barnstorm Offline
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I try to drive the pits and run the shifter up for several gear changes and put some heat in the motor 140 deg....most cars I know need a "clean out pass". If sometimes the 1st pass is the best usually really good air or the start line prep is the only one of the day and bite goes away.

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Re: Struggling, any idea why first run of day so far off??? [Re: Barnstorm] #347729
06/15/09 03:36 PM 06/15/09 03:36 PM
Joined: Jan 2003
Posts: 19,363
Las Vegas
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Well this is an issue that I for one do not have. We do warm the engine and drivetrain before we make out first pass, HOWEVER I only do it if there is ample cool down time afterward to bring all the the temps back down to where they would normally be while racing. If there is not time we will bring the engine up to temp and cool it down. Will put a little heat in the trans just before we make a pass on the brake. Otherwise the first pass would be a waste of time and sometimes one is all we get.

"I am not ashamed to confess I am ignorant of what I do not know."

"It's never wrong to do the right thing"
Re: Struggling, any idea why first run of day so far off??? [Re: Al_Alguire] #347730
06/15/09 04:23 PM 06/15/09 04:23 PM
Joined: Jul 2006
Posts: 388
Michigan
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SD800 Offline
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Michigan
Both my cars do the same thing, I just figured everthing needed a pass to heat things up.

You'll have plenty of time to sleep when your dead, let's go
Re: Struggling, any idea why first run of day so far off??? [Re: SD800] #347731
06/15/09 04:54 PM 06/15/09 04:54 PM
Joined: Feb 2008
Posts: 364
Kentucky
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sc301v Offline
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Kentucky
Alky or gas..

Mine dragster is alky and on a normal summer day it would go 4.83 1st pass and pick up .01 to .015 the next shot.

Thats just driving the car around and getting about 180 degree's in the motor then let it set and soak around a half hour.

During the weather changes from day to night i will never change 3 hundreths.If i do its time for a jet change.
Re: Struggling, any idea why first run of day so far off??? [Re: sc301v] #347732
06/15/09 05:06 PM 06/15/09 05:06 PM
Joined: Sep 2003
Posts: 481
Cheswick, PA
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Bob_Spelic Offline OP
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Joined: Sep 2003
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Cheswick, PA
my dragster is gas powered. The variations from night and day and from round to round are not too bad. I can follow the weather and predict them. It is the .130 to .140 from the first time run to the second time run (usually about an hour to and hour and a half apart). Even when the weather station says the relatively same DA, baro pressure, humidity and temp. Being off by .130 is just a killer when I only get one time run.

Somene mentioned plugs getting loaded up and not cleaned until after the first run. This weekend I will chnage plugs after the warm-up and see if the first run is a good one. I just don't want to throw away the first run, but that is what I have to do. If we only get one time run, I take a wild stab at the dial (subtract .130 from run #1) and plan on playing the stripe.

Getting a good time trial #1 would be real nice, but it does not appear to be temperature in my case. I too allow plenty of cool down time after getting everything hot. I stage the car at 160...always.

Bob Spelic
Re: Struggling, any idea why first run of day so far off??? [Re: Bob_Spelic] #347733
06/15/09 05:41 PM 06/15/09 05:41 PM
Joined: Feb 2008
Posts: 364
Kentucky
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sc301v Offline
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Kentucky
Let me do a little more pondering on this tonight and i will get with ya tomorrow Bob..

This should be a fixable problem cause i have never had anything vary any where near that much.

Weather my dragster or door car on gas or alky.
Re: Struggling, any idea why first run of day so far off??? [Re: sc301v] #347734
06/15/09 06:22 PM 06/15/09 06:22 PM
Joined: Apr 2004
Posts: 324
Northport, al.
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tvt59 Offline
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Northport, al.
I had the same problem with my bracket car. I fixed it by changing to 5w-30 mobile 1 oil, Syn. trans and syn rear diff fluid. I also kept two sets of plugs. One set to warm up on and work on it around the house. I would take the race plugs out when I did my Monday maint. And reinstall them at the track after I warmed it up.
Re: Struggling, any idea why first run of day so far off??? [Re: sc301v] #347735
06/16/09 09:06 AM 06/16/09 09:06 AM
Joined: Sep 2003
Posts: 481
Cheswick, PA
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Bob_Spelic Offline OP
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Cheswick, PA
SC, please do and if you come up with anything, let me know. It will be greatly appreciated.

I am going to try to swap plugs out to a new set after getting it warmed up and while it is heat soaking!

Bob spelic
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