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Author
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Topic: Finally floored the fastback!! - Need help
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rockafellz
Gearhead Posts: 1291
From: San Lorenzo, CA, USA
Registered: Aug 2001
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posted 05-05-2003 03:11 AM
   
Ok guys, in preparation for the race that I missed  , we installed a Proform shift light and set it to 5800 and added a 6400 MSD rev limiter pill. I've heard the msd pills can sometimes be off a few hundred.We took the car out on Saturday afternoon to a deserted industrial area. Remember, i've never floored my motor until this point because it's a street car and I want proper break-in. Well, I floored it and didn't realize how fast RPMs shoot up when the pedal is floored   , the light lit up at 5700-5800rpm followed by "BAA BAA BAA BAA BAA" rev limiter kicking in. I didn't even get a chance to shift into 2nd. Either the 6400 RPM pill is off by 400rpm or it kicked in at 6400rpm but it was awefully quick since the rev limiter kicked in as soon as the shift light lit up. My goal is to shift at 6000. What should I set my shift light to? And I installed a 6600 rpm pill to prevent the rev limiter from ever kicking in again. By the way, the rev limiter sounds aweful. I had to make sure my motor was alright by pulling a nice burnout. Erik ------------------
1966 Ford Mustang 2+2
Mine - Restomod in Progress 1966 Ford Mustang Coupe
Dad's - Original Unrestored
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64FalconF-16
Gearhead Posts: 191
From: Republic Of Texas!! Temporarily living in KY
Registered: Feb 2002
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posted 05-05-2003 07:37 AM
There is always a delay on a shift. For me on a footbrake car like yours I subtract 200 RPM for my shift light. In other words if I want to shift at 6000 I set my shift light for 5800. If you have a Tach with recall you can work with the pill until you get it to 6000 RPMs.I have had MSD pills off a few hundred before. scares the He!! out of you huh? When I first let my Fiancee drive my 11 sec Brand X (non-Chebbie) car. I set the shift light at 5800 and the rev limiter was at 6200. It was off and I did not know it. She ran the car down the track and shut it down. half track. She thought she blew the motor. I checked everything out. No problems. Sent he out again, same thing, shutdown. Found the bad pill and had to convince her she did not break my car and to get back in the car. That was two years ago and now I can't get her out of the car. ------------------
Rick Austin 64 Pro-Street Falcon
351C 4V 8.1s in 1/8
79 Ford Bronco 4 X 4
400 9.9s in 1/8
2000 F-150 XLT 5.4L
1932 Ford 3 window Coupe
http://mustangsandmore.50megs.com/64FalconF-16.html
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clevelandstyle
Gearhead Posts: 638
From: Connersville, IN
Registered: Jul 2001
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posted 05-05-2003 01:20 PM
I personally, would be more suspect of the Proform shift light being off, rather than the MSD. Proform makes some cheap stuff. ------------------
Ben
Grabber Green '70 Mach I 351C 4V
Robbin Egg Blue '79 Fairmont 351C 4V [This message has been edited by clevelandstyle (edited 05-05-2003).]
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Moneymaker
Administrator Posts: 19704
From: Lyons, IL, USA
Registered: May 99
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posted 05-05-2003 02:21 PM
quote:
Originally posted by clevelandstyle:
I personally, would be more suspect of the Proform shift light being off, rather than the MSD. Proform makes some cheap stuff.
I agree.------------------
Alex Denysenko
Co-Administrator and Moderator NHRA/IHRA/SRA member and licensed Superstock driver
MCA member# 53321
NHRA and IHRA SS/LA National Record Holder '00,'01,'02,&'03
First SS/MA in the TENS!
Fleet of FoMoCo products including 88 ASC McLaren Mustang #28
Professional Manwhore
The Barry of BarrysGrrl Quote #1: "I never met a magazine mechanic I liked."
Quote #2: "Make sure brain is in gear before engaging mouth!"
Quote #3: "If you can't run with the big dogs, stay on the porch!"
www.moneymakerracing.com
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Dave_C
Gearhead Posts: 744
From: Gadsden, Al
Registered: Aug 99
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posted 05-05-2003 02:23 PM
You can use a digital ohm meter to check the MSD chips. Set the meter for the 20K ohm scale and touch the probes to the legs on the chip.A 6400 chip will measure about 4.98 on the 20K scale. The 5800 should be about 4.35 All measurements may vary by .01-.02 depending on the meter. A couple of years ago I measured all my chips and made a chart. I also checked several chips belonging to friends to verify mine. While these are not exact, they are close. I made this list when I had an adjustable chip. It coulf be set with a screwdriver anywhere from 0 to 12K rpm. MSD Chips
RPM Resistance
3000 1.91
3400 2.21
4000 2.70
4600 3.21
5000 3.58
5200 3.77
5400 3.95
5600 4.16
5800 4.35
6000 4.57
6200 4.75
6300 4.88
6400 4.98
6500 5.10
6600 5.20
6700 5.32
6800 5.43
6900 5.55
7000 5.65
7200 5.91
7400 6.12
7600 6.38
7800 6.63
8000 6.89
8600 7.69
8800 7.97
9000 8.27 Later,
David Cole
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jsracingbbf
Gearhead Posts: 1677
From: Batesville,MS. , U.S.A.
Registered: Mar 2002
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posted 05-05-2003 03:59 PM
David's post brings us to another idea, albeit and old one. You can make an adjustable RPM chip out of an old Decade box. ( DECADE BOX = One knob, many selectable resistors @ less than 1% tolerance ) Although the one's you buy from MSD look nicer. Way back when I used an old decade box because I was into saving every little penny I could, so I didn't opt for the $40.00 MSD RPM selector. BTW if anyone wants to play with a decade box as a RPM selector let me know I still have a couple around here somewhere.
It makes a nice little project. Although it probably takes up more than $40.00 bucks worth of your time.
It's also a good way to get those "in- between" values, like 5560 RPM. Why you would need this I dunno but with precision resistors it can be done.Take care,
JS
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jsracingbbf
Gearhead Posts: 1677
From: Batesville,MS. , U.S.A.
Registered: Mar 2002
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posted 05-05-2003 04:04 PM
I forgot to mention the difference between a decade box and an adjustable RPM chip ( like David had) is precision resistors and the "click"------ anotherwords it "stops" at each position you assign a resistance value to.
So in this way you could make "tags" for the box and label them in RPM increments just like the MSD unit. JS
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jkilroy
Gearhead Posts: 1719
From: Vicksburg, MS
Registered: Dec 99
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posted 05-05-2003 05:11 PM
Why don't you just buy a $2 10 ohm cermet potentiometer from DigiKey and wire it in. You could then set it with a meter according to the chart shown above.------------------
Jay Kilroy
68' Fastback GT 390
"No such thing as a cam thats too big" [This message has been edited by jkilroy (edited 05-05-2003).]
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jsracingbbf
Gearhead Posts: 1677
From: Batesville,MS. , U.S.A.
Registered: Mar 2002
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posted 05-05-2003 07:32 PM
That works great Jay----- until you decide you want to change launch RPM in the staging lanes. makes it nice to have a the positions marked.
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Dave_C
Gearhead Posts: 744
From: Gadsden, Al
Registered: Aug 99
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posted 05-05-2003 10:15 PM
quote:
Originally posted by jsracingbbf:
That works great Jay----- until you decide you want to change launch RPM in the staging lanes. makes it nice to have a the positions marked.
It actually wasn't very hard to change the adjustable chip in the lanes. Every 1/4 turn of the screw equals 100 rpm. Just had to keep a very small screwdriver in the box with the tire guage and shoe polish. Pull the chip, adjust it and put it back. This is the chip I had:
http://www.jegs.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=3257&prmenbr=361 Later,
David Cole
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