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Author
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Topic: hooks better, but no et drop?
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chip67
Gearhead Posts: 245
From: louisville, ky, jefferson
Registered: Oct 2004
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posted 10-02-2004 11:46 PM
   
hey fellas. good to be back. since my last posts i took alex's advice and got the caltracs bars and have started making progress with tunning them. i went from low 1.7's to mid 1.6's and even got down to 1.63 a couple of times when they dressed the starting line. my problem is ive seen no change in et or mph at all! this aint right. i was running between 7.55 and 7.65 before i got the bars with the 1.72 60 ft times. now ive dropped a tenth off the 60 and got nothing at the other end. why? i hope steve66 is still around or maybe alex can give me an idea. thanks for any help.------------------
coupe, 306, 4 speed, 4.11's. pump gas, n/a street car. best so far is 7.55 (1/8 mile) at 92mph with 1.64 60ft. time.
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N266fords
Gearhead Posts: 1404
From: Spokane ,WA USA
Registered: Apr 2003
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posted 10-03-2004 12:06 AM
I am no expert but could you be hooking well enough to cause a bog. This would make sense to me. the engine might be bogging just enough that its not falling on its face but enough to slow you et down from what you gained on a good launch. Just an idea. do you have a big enough accelerator pump 50cc this might be one solution. Like I said I am not an expert I would listen to what steve and alex say.Bruce
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chip67
Gearhead Posts: 245
From: louisville, ky, jefferson
Registered: Oct 2004
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posted 10-03-2004 12:44 AM
n266, i launch the car at 6600 on a 2-step, drop the clutch and its wide open. i been trying to watch the tach off the line to see if theres any slipping in the tires or clutch. i can tell you that the car crosses the finish at 7k in 3rd gear after its bumped the rev limiter a couple of times so 93 mph is about all it gets to. by the time id shift into 4th it wouldnt make a diff since its so close to the end. i just really expected to see a difference at the finish line with a better et since the 60ft got so much better, but im stumped.------------------
coupe, 306, 4 speed, 4.11's. pump gas, n/a street car. best so far is 7.55 (1/8 mile) at 92mph with 1.64 60ft. time.
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XR7
Gearhead Posts: 129
From: north Idaho
Registered: Mar 2003
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posted 10-03-2004 11:52 AM
Usually 1 tenth on the 60 ft translates to 2 tenths in the 1/4 ! I think the air conditions were probably diff. between your times. Was the temp and elevation of the air the same? My car runs 2 tenths or more slower with bad air, compaired to good air. I have a buddy who has all the weather stations and computer stuff at the track so I know when the air is at 1500 ft or if it's at 6000. Another thing it could be is the chassis is hooking better but the engine is off a bit on HP for any number of reasons.------------------
68 Cougar XR7, 428 4-speed, Best ET 6.82 @ 101 1/8, 10.69@ 127.44 with 1.51 60 ft. Street legal all steel car w/ full interior.
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kid vishus
Gearhead Posts: 6098
From: middle of NC
Registered: Oct 2000
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posted 10-03-2004 12:47 PM
quote:
Originally posted by chip67:
i can tell you that the car crosses the finish at 7k in 3rd gear after its bumped the rev limiter a couple of times so 93 mph is about all it gets to.
I would try short shifting it so it would get into 4th gear before the finish line. Either that or I would put a higher chip in the rev limiter. It's been my experiance that even 'touching' the rev limiter one time kills ET.
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chip67
Gearhead Posts: 245
From: louisville, ky, jefferson
Registered: Oct 2004
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posted 10-03-2004 04:04 PM
i thought about trying that kid next time out. maybe puting the shift lite at 6200 instead of 6400 and seeing if i hit 4th would help. the air was about the same as the previous week, the mph difference was within 1/2 mph both nights. i went back to compare the acceleration differences between last week's 7.564 @ 91.66 with 1.675 60ft. VS. this weeks 7.567 @ 91.48 with 1.638 60ft. i noticed the biggest loss came between the 60ft. mark and the 330ft and that by the end of the track the time difference between the 594ft and the 660ft were identical on the timeslips. given that launch rpm, air, and shift points were the same could the car be recovering at a weaker point in the powerband due to the tires hooking up better? hooking up would naturally put the revs slightly lower when the car recovered but mercy! launch at 6800 or 7k? that cant be right, revs never go under 5200 the whole run. if its the clutch i dont smell a thing. ------------------
coupe, 306, 4 speed, 4.11's. pump gas, n/a street car. best so far is 7.55 (1/8 mile) at 92mph with 1.64 60ft. time.
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n2oMike
Gearhead Posts: 2419
From: Spencer, WV
Registered: Jan 2001
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posted 10-03-2004 04:27 PM
As someone else said, it's probably just bad air... as improving the 60ft should definitely improve the et! Generally a tenth in the first 60ft gives you around a tenth and a half at the end. As far as launching is concerned, the harder my car is launched, the quicker it goes. I generally launch at 6800 rpm off the bottle, and shift at 6800. Launching at 7k makes it go a tic faster. (top end rev limiter is set to 7.2k) I ran my best 1/8 time (off the bottle) of 7.48 when at the strip with a friend who had a Camaro that was running similar times... I decided to launch at 7k rpm, and it ran that 7.48. I was going to launch at 7.2k, but I was too late to get to the staging lanes, and they made my go back.  It will make you cringe the first time, but turning the wick up at the starting line will generally make the car go quicker as long as it isn't completely blowing the tires off or dragging it's back bumper.  Good Luck! ------------------
Mike Burch
66 mustang real street
302 4-speed 289 heads
10.63 @ 129.3
http://www.geocities.com/carbedstangs/cmml_mburch.html
http://www.fortunecity.com/silverstone/healey/367
http://www.mustangworks.com/cgi-bin/moi-display.cgi?220
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chip67
Gearhead Posts: 245
From: louisville, ky, jefferson
Registered: Oct 2004
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posted 10-03-2004 09:05 PM
im going to try both this friday, short shifting a tad and launching harder, of course on separate passes so im only adding one variable at a time.------------------
coupe, 306, 4 speed, 4.11's. pump gas, n/a street car. best so far is 7.55 (1/8 mile) at 92mph with 1.64 60ft. time.
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bud4660
Gearhead Posts: 513
From: Mesquite, Tx. M&M #2925
Registered: Apr 2003
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posted 10-04-2004 09:08 AM
Have a friend stand at the starting line and watch your tires. I went to the track sat night with a buddy and his was rolling the tires into the the ground. I talked him into putting more air in the slicks each run. He would only go 1/2 pound at a time. Some of these old guys dont listen real well. He's 62 and I'm 49....lol... But it went quicker each run. He also made the quickest run ever in it. I still think it needed to go up in tire pressure 2-3 more pounds. The track was real good. There were some blower cars testing, so they sprayed alot of VHT down. It was also bogging from the traction. He couldnt tell from inside because it was so slight. But it was there.
The vehicle was a 65 F100 stepside with an FE and a C6. It also has a cage for 10 second blast's. Thats all I'm telling....lol
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