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Discussion Starter #1
Hello everyone this is my first post here. I was hoping someone could help me with a little dilema:

I just switched to a C4 from a T5. I built the C4 with a TCI reverse manual valve body and a Redneck 9.5" 3000 stall. If I try to footbrake the car, it will only stall to around 1900 rpms before it wants to crep forward. I have new brakes on the car (still has rear drums). If I leave at idle, the converter still doesn't seem to flash to more than 2000 rpms. I lost 3 tenths in the 60ft alone from the old T5 setup.

Is the converter stall speed set incorrectly? Should I switch to a transbrake to keep the car from rolling and to use all the stall speed? Here are the specs on the car:

-Stock bottom end 1990 302
-Edelbrock RPM Heads (2.02/1.60 valves)
-PBM Camshaft (220/220 .498/.498)
-Edelbrock Air Gap Intake
-Holley 650 DP carb
-Mallory Ignition
-4.10 gears
-27x10.5 MT ET Streets
-Ford Racing Upper Control Arms
-Lakewood "Traction Action" Lowers
-Lakewood 50/50 shocks and 90/10 struts
-Eibach Drag Springs
-No smog,AC,Heat, etc
-Fuel Cell
-Battery Relocation
-No sway bars

I was launching at 4000 with the old T5 and shifting at 6500. The car was getting 1.7-1.8 60fts and running 12.7-12.9 (I didnt get much practice). What should I do? Sorry for such a long post but Im trying not to forget anything. Thanks!
 

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Hello everyone this is my first post here. I was hoping someone could help me with a little dilema:

I just switched to a C4 from a T5. I built the C4 with a TCI reverse manual valve body and a Redneck 9.5" 3000 stall. If I try to footbrake the car, it will only stall to around 1900 rpms before it wants to crep forward. I have new brakes on the car (still has rear drums). If I leave at idle, the converter still doesn't seem to flash to more than 2000 rpms. I lost 3 tenths in the 60ft alone from the old T5 setup.

Is the converter stall speed set incorrectly? Should I switch to a transbrake to keep the car from rolling and to use all the stall speed? Here are the specs on the car:

-Stock bottom end 1990 302
-Edelbrock RPM Heads (2.02/1.60 valves)
-PBM Camshaft (220/220 .498/.498)
-Edelbrock Air Gap Intake
-Holley 650 DP carb
-Mallory Ignition
-4.10 gears
-27x10.5 MT ET Streets
-Ford Racing Upper Control Arms
-Lakewood "Traction Action" Lowers
-Lakewood 50/50 shocks and 90/10 struts
-Eibach Drag Springs
-No smog,AC,Heat, etc
-Fuel Cell
-Battery Relocation
-No sway bars

I was launching at 4000 with the old T5 and shifting at 6500. The car was getting 1.7-1.8 60fts and running 12.7-12.9 (I didnt get much practice). What should I do? Sorry for such a long post but Im trying not to forget anything. Thanks!
welcome! first off the tune on the engine has to be rearranged some.
the timing curve will need attention.
I will make it brief, 10/18 inital timing and 28/38 total timing at 2500/3000 rpm
shoot in the middle for your first try. skip this step and you will piss in the wind standing on the front of a boat.
Next thing the converters are made to be flashed at the line.
In other words idle until time to go!
you will lose ET footbraking.
the cam is conservative so inital timing will need to be lower like 12 degrees.
start with that see what you get.
Javier
 

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Discussion Starter #3
I had the timing set at 18 initial I believe. I have the lightest springs in the distributor. Should I put in some heavier springs? I still think there is an issue because this "3000" converter doesnt flash higher than a stock converter. Thanks for your help ranchero it is much appreciated
 

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Discussion Starter #4
Also, the car doesnt pull very hard until 3500 rpms or so which is why the low flash is killing my times. I have tried calling Redneck 3 different days now and left messages but had no luck with a returned call.
 

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The "rating" on a convertor is at best a guess by the manufacturer. It will vary between different vehicles due to weight, torque, etc. The rated # (3000-3500) is what it will flash to on a transbrake. If you want full stall pony up the $539 for a PA transbrake. That will tighten up your 60 fts and be similar to sidestepping the 3rd pedal.

I have a weaker engine in a 92 GT with a built c4, it has a 3000-3500 tci streetfighter convertor and it will stall on the footbrake to about 1900-2000 before breaking the tires free. Leaving from idle trying to flash the convertor will usually slow you down as you have to "tighten" up the drivetrain before the car will move. At least it did for me.

Hope this helps
 

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By installing the transbrake you'll be faster than you were with the manual and far more consistent. Leaving on the transbrake will put you at the same 60 ft at the manual and you'll get down the track better due to not having missed shifts, slow shifts, etc. You need to look at why your 60fts are slow, you've got a ton more power and mine runs 1.8 60's all day leaving on the convertor at 1900 rpms.
 

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you need a converter that will flash to 3000 to 3500 with what you have now, ptc restalled mine for $150 and got it where i wanted it the first time.
 

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Spend the money and buy a loose converter. I would highly suggest ATI. Going from a 10" PTC (2800 flash stall) to an 8" ATI (4500 flash stall) took me from 12.14 @ 109 to 11.35 @ 117 WELL worth the money and much better customer service then "Redneck".

With torque converters and many other parts, you get what you pay for.
 

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i have a redneck set up also mine is supposed to be a 4000 stall but on the tranny break it stalls at 4300 and pulls 1.5x 60's call redneck and tell them to loosen it up for you they have great coustomer service. and get a tranny break.
 

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Discussion Starter #11
I just got off the phone with Redneck and they said I need a stall speed around 4000-4200. They will reset mine for $150 which isnt bad, but they are the ones that told me to go with the 3000 in the first place so I kinda hoped they would cut me some slack but oh well. He also said a transbrake would be helpful but I should get the converter loosened up first and see where that gets me.
 

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talk to nutts on here first he sent his back 3 or 4 times and the stall didnt change any every time. ptc will restall anyones converter for 150 and get you the stall you want even if you dont use them give them a call and talk to them and see what they can do for you.
 

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Discussion Starter #13
I called PTC and I think Im going to send my converter to them. They said they will look at it and either re-stall it or give me $250 or so towards one of their race converters.
 

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Discussion Starter #16
I know that it cannot be footbraked to full stall speed, but even the 3rd gear trick only flashes to maybe 2500. It is just too tight. PTC had me go online and fill out one of their info cards..Redneck never asked me to.
 

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You may want to consider a tight 8" converter built for a nitrous motor. You would get the stall speed and 'flash' you want and have a lighter converter at the same time. 9" and 10" converters are heavy and rob horsepower.

See if you get them to build a tight 8" converter that will stall like you want without being too loose.
 

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The 8" converter will lock up tighter down track, be more efficient, and will weigh around 10lbs less than the 9.5" converter with the same stall. I also run a redneck 9.5" but it's a 4000 stall, and I also run one of their t-brakes. Zero complaints for both. I'm going to step up to a 4800-5000 stall, so I am saving up for an 8" converter for my application. I agree, it is an astronomical price difference going to an 8", don't know what part/parts internally constitute the extra cost. Alot of times people use the old quote "you get what you pay for" just to justify why they spent so much with no real proof or reason. From the research and testimonials I've been seeing on an 8" converter, there are real performance gains to be had. Hopefully I'll find out, probably not till next spring though. Alot of $$$$$ yet to save up!
 

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What would the difference be, roughly, in ET with an 8" 4200 stall vs a 9.5" 4200 stall?
Impossible to know because there are too many varibles to consider. I would be willing to bet the gains would be greater on a slow car vs. a faster. In other words, a 10 second car wouldn't gain as much as a 12 second.

Something else you might want to consider also.

Some of the e.t. you lost swapping to the C4 was due to the huge 1st and second gear ratio advantage you had with the T5. The T5 has a 3.15:1 1st gear and a C4 has a 2.45:1 1st gear. BIG difference there. Its almost the equivalent of launching the T5 starting in 2nd gear rather than 1st. PA makes a lower gear planetary for a C4 that will lower the 1st gear ratio to a 2.75 and the 2nd gear ratio to help. That will help a little also. The biggest thing is getting the converter stall and flash point right. Once you do that, you will see a big difference.
 
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