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Author
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Topic: New times with C6 to C4 swap
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Jerry Piner
Gearhead Posts: 257
From: staunton, va
Registered: Dec 2001
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posted 08-25-2004 11:21 AM
 
Finally swap my C6 and 10" dacco for C4 and 10" PTC race. People have been telling me the swap would pick me up 2-4 tenths. Well needless to say not to happy with results only picked up a little over a tenth. Both transmissions have manual valve bodies, old converter flashed @4000 new one @4400. Didn't pick up any in the 60 ft.[This message has been edited by Jerry Piner (edited 08-25-2004).]
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Hans olsson
Gearhead Posts: 936
From: Sweden
Registered: Apr 2000
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posted 08-25-2004 02:07 PM
What about things like temp and barometric pressure? Headwind or tailwind,these things can make a big difference.
That swap should be worth more than a tenth!
------------------
- VIN 1F05M139343
- 71 Mach 1 Ram-Air
- 351C 4V 285 HP
- F-G/Stock Aut
- Stockers are way cool!
[This message has been edited by Hans olsson (edited 08-25-2004).]
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Jerry Piner
Gearhead Posts: 257
From: staunton, va
Registered: Dec 2001
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posted 08-25-2004 02:27 PM
yeah that is what everyone told me but based on similiar weather and what my brother-in-laws car ran, since my car is usually .08 faster than his, the car only picked up .12 and none in 60 ft.
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Dubz
Gearhead Posts: 2005
From: Manitoba Canada
Registered: Oct 2002
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posted 08-25-2004 03:06 PM
damn, that suckswhat did you car weigh in at for race weight setup with both. I would have thought the weight change alone from the c6 to c4 would knock off at least a tenth. Did you have to add weight or anything to reach a allotted restriction? or any other changes?
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Jerry Piner
Gearhead Posts: 257
From: staunton, va
Registered: Dec 2001
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posted 08-25-2004 03:17 PM
No other changes just swapped transmissions from one week to the next.
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70coupe
Gearhead Posts: 493
From: Toronto,Ontario,Canada
Registered: Aug 2000
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posted 08-25-2004 04:58 PM
I would say that your c6 converter is a better one that the c4. I gained between 3 and 4 tenths instantly and my 60' decreased substantially. Less weight and rotating mass equals a better ET. If your c6 had roller bearings and your c4 doesn't you might not gain as much but it sounds like a converter issue.
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kid vishus
Gearhead Posts: 7251
From: middle of NC
Registered: Oct 2000
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posted 08-25-2004 05:53 PM
quote:
Originally posted by 70coupe:
...but it sounds like a converter issue.
I agree. When I switched from a C6 to a C4, my car picked up almost 3 tenths. Also, a poorly matched (or just plane old bad) convertor will kill ET. And stall speed is only a small part of what makes them work. I changed brands one time, both convertors stalled the same, but the better of the 2 ran half a second faster in the 1/4.
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clevelandstyle
Gearhead Posts: 1558
From: central Indiana
Registered: Jul 2001
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posted 08-25-2004 06:42 PM
True.
There is way more to a converter than stall speed. My car picked up a couple tenths with the C6-C4 swap and I used the same converter with a spline adapter. That's apples to apples.------------------
Ben
Grabber Green '70 Mach I 351C 4V
Robbin Egg Blue '79 Fairmont 408C 4V, best time to date is 10.50 @ 125mph
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Jerry Piner
Gearhead Posts: 257
From: staunton, va
Registered: Dec 2001
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posted 08-26-2004 11:13 AM
I wouldn't think the converter would be the problem since everyone told me how bad the Dacco's are and all i have heard is good about PTC and how good thier converters are.
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67coupe
Gearhead Posts: 491
From: dallas NC usa
Registered: Nov 2000
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posted 08-27-2004 11:49 PM
sorry to but in here but cleavland style where did u find the spline adapter never seen one and i got a good 10" for a c6 and I will be needing a one for a c4 soon so that would be nice thanks for any help  ------------------
Josh
67 coupe with 351c (currently broke:( )
8.41 in the 1/8
1.90 60'
at 82.03 mph
94 Explorer
30 model A currently rustbucket
in process 67 convt with efi 5.0 and t5(now mostly complete and on the road legally)
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wildfire466
unregistered
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posted 08-28-2004 12:49 AM
PA Racing
http://www.usaplaza.com/scripts/wcom_producttree.asp?StoreID=1078&ProductID=32346------------------
http://www.geocities.com/wildfire1mustang/
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clevelandstyle
Gearhead Posts: 1558
From: central Indiana
Registered: Jul 2001
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posted 08-28-2004 10:20 AM
I got mine at JPT. It was only $15.  ------------------
Ben
Grabber Green '70 Mach I 351C 4V
Robbin Egg Blue '79 Fairmont 408C 4V, best time to date is 10.50 @ 125mph
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n2oMike
Gearhead Posts: 3058
From: Spencer, WV
Registered: Jan 2001
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posted 08-28-2004 12:14 PM
quote:
Originally posted by Jerry Piner:
Finally swap my C6 and 10" dacco for C4 and 10" PTC race. old converter flashed @4000 new one @4400. Didn't pick up any in the 60 ft.
Most 10" converters don't stall that high. I would say there is either something wrong with that unit, or you need to go with an 8". Probably both. 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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67coupe
Gearhead Posts: 491
From: dallas NC usa
Registered: Nov 2000
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posted 08-28-2004 06:38 PM
thanks guys ill check into that ------------------
Josh
67 coupe with 351c (currently broke:( )
8.41 in the 1/8
1.90 60'
at 82.03 mph
94 Explorer
30 model A currently rustbucket
in process 67 convt with efi 5.0 and t5(now mostly complete and on the road legally)
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Dave_C
Gearhead Posts: 1123
From: Gadsden, Al
Registered: Aug 99
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posted 08-29-2004 02:31 PM
Just a couple of thoughts.1. Is it possible that the C-4 has some kind of trouble? Some sort of internal drag problem? The C-6 may have been good and "loose" and the C-4 might just be "tight". Some years ago when I had just a regular 351W in my 69 I swapped from a C-4 to a C-6. The C-4 was stock, other than a shift kit and the C-6 was partially rollerized. The swap cost me .12-.13 in the 1/8. Everyone said it should have slowed more, but it didn't. Later on I gained that back and a little more with a swap to a glide. 2. The converter might just be too loose. send it back to PTC. Kenny at PTC is the king of customer service. He will work with you and adjust the stall speed for free is the converter is still new. I've used many of his converters. Including a 10" that stalled about 4200 behind my 383W. That same converter was rebuilt and is now in a buddies car behind a 460. Jerry Smith and some other guys on here will vouch for PTC as well. I recently installed one his in my little brothers 66 Mustang behind a 302. Works great. Running 7.50's 1/8 3. FYI, I have weighed a C-6 and C-4, dry weight w.o converter is 47 lbs difference. David Cole ------------------
557 BBF Powered, alcohol injected rear engine dragster. 4.90 @ 143 1/8 mile. 1.09 60'. I've got to be crazy to drive this thing.
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kid vishus
Gearhead Posts: 7251
From: middle of NC
Registered: Oct 2000
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posted 08-30-2004 07:54 PM
quote:
Originally posted by Jerry Piner:
Finally swap my C6 and 10" dacco for C4 and 10" PTC race.
Just my opinion here so take it for what it's worth; a 10" convertor is a good street/strip unit unless it's behind a supercharged 500+ inch BB, or behind a big motor that is seeing a considerable amount of nitrous. 90% of the smallblock racemotors out there need an 8" convertor behind them to work properly. 5% need a 9" and the rest need a 7" convertor. Your motor really needs a good 8" behind it. Something that stalls around 4400-4600 (like what you have now), but in an 8".
But like I originally said, it's just my opinion and I don't think any 10" convertor is a good choice for a dedicated racecar.
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Moneymaker
Administrator Posts: 29200
From: Lyons, IL, USA
Registered: May 99
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posted 08-30-2004 10:19 PM
It's the converter, end of story. 
Not a bad product, just a poorly matched one towards your application.
4400 stall ten inch has no place behind your motor Jerry.The converter is physically too big to flash fast enough for your engines needs.
The tenth pick up was due to the better efficiancy of the C-4.
The right converter would have netted the afore mentioned 2-3 tenths decrease in ET.
PTC is a very reputable outfit.
Call Kenny and see what they'll do about swapping you out for an 8 inch which is what you should have had from jump street. ------------------
Alex Denysenko
Co-Administrator and Moderator NHRA/IHRA/SRA member and licensed Superstock driver
MCA member# 53321
NHRA and IHRA SS/LA & SS/MA National Record Holder '00,'01,'02,'03,& '04
First SS/MA in the TENS!
IHRA division 5 Superstock Champion
Fleet of FoMoCo products including 88 ASC McLaren Mustang #28 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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Dynoram
Journeyman Posts: 51
From: ford country
Registered: May 2003
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posted 08-30-2004 11:52 PM
When you say ptc do you mean pro torque converters (joe)? cause there customs are usually 9.5 for street driven cars smaller for track... there usually on the money but nobody beats custom ati's.[This message has been edited by Dynoram (edited 08-30-2004).]
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