Time slip questions?

JTMunk · 04-15-2003, 09:11 AM

My first time out at the track and my car didn't seem to pull at all in 3rd gear (C4 trans). I'm wondering if anyone can tell if I have problems from looking at my timeslip information. 1st and 2nd pull hard to the shift point (6200 RPM) but when I shift to 3rd the tack stays at 5000 RPM and doesn't budge. 3rd gear feels like I'm on cruise control.

60ft - 1.700
660ft - 7.760, 87.55mph
1320ft - 12.460, 99.56mph

Specs:
347 cubic inch, Twisted Wedge Heads, Holley Systemax intake, Trick Flow Stage 2 cam (545 in 565 ex), 42 lb injectors, 70mm Throttle Body, 80mm Pro-M mass air, Cartech fuel system with -8 feed -6 return, Paxton Regulator @ 45psi, PMS, C4 Trans, PI 3500 stall converter, 3.73 gear, 28 x 12.5 ET Streets, car wt 3200 lbs

Thanks for your help.

84gt347 · 04-15-2003, 09:34 AM

I have heard cars do that at the track and wondered if they are suppose to sound that way. It sounds like converter issues, but i really dont know. obviously you did pick up mile an hour, 87 to 99 but if your tach stays at 5000 rpm then it sounds like your converter was locking up to produce mph rather than the motor????

Dark_5.0 · 04-15-2003, 10:51 AM

Obviously something is wrong your car is about 7mph short of whereit should be.

Most cars pick up 20+ mph from the 1/8th to the 1/4 you only picked up 12 mph.

Something aint right,

fiveohpatrol · 04-15-2003, 12:19 PM

Sounds like a torque converter issue to me.

Dark_5.0 · 04-15-2003, 03:43 PM

With that 1/8th mile your 1/4 mile time shoulda been a 12.11 @110mph.

Thats what the analyzer said

JTMunk · 04-15-2003, 04:00 PM

I talked with Harold at Dynamic Racing Trans and he thinks that the converter is not stalling high enough. He recommended at least a 4200 RPM stall.

Using the footbrake, it's difficult to raise the RPMs to 2000 before it pushes the car. Harold said I should be able to foot brake it to 3000 to 3500 RPMs.

PI built the converter with all of my information and said it should stall at 3500 to 3800 RPM.

What do you think?

I realize my 3.73 gear ratio and 28 inch tall tires are not ideal for my natural aspirated 347 but they should be close after I get a YS trim on there.

dragstang86 · 04-15-2003, 05:40 PM

i have a c-4 with a Performance automatic 3500 stall...with everything in my sig i had...

1.68 60ft

7.93 1/8 @ 85.65mph

12.57 1/4 @ 105.12mph

I also have a 373 gear with a 28 tall tire....

04-15-2003, 09:11 AM	#1
JTMunk Registered Member Join Date: Jan 2002 Location: Albion, IN Posts: 6	Time slip questions? My first time out at the track and my car didn't seem to pull at all in 3rd gear (C4 trans). I'm wondering if anyone can tell if I have problems from looking at my timeslip information. 1st and 2nd pull hard to the shift point (6200 RPM) but when I shift to 3rd the tack stays at 5000 RPM and doesn't budge. 3rd gear feels like I'm on cruise control. 60ft - 1.700 660ft - 7.760, 87.55mph 1320ft - 12.460, 99.56mph Specs: 347 cubic inch, Twisted Wedge Heads, Holley Systemax intake, Trick Flow Stage 2 cam (545 in 565 ex), 42 lb injectors, 70mm Throttle Body, 80mm Pro-M mass air, Cartech fuel system with -8 feed -6 return, Paxton Regulator @ 45psi, PMS, C4 Trans, PI 3500 stall converter, 3.73 gear, 28 x 12.5 ET Streets, car wt 3200 lbs Thanks for your help.

04-15-2003, 09:34 AM	#2
84gt347 Registered Member Join Date: Mar 2002 Location: sherwood Forest Posts: 291	I have heard cars do that at the track and wondered if they are suppose to sound that way. It sounds like converter issues, but i really dont know. obviously you did pick up mile an hour, 87 to 99 but if your tach stays at 5000 rpm then it sounds like your converter was locking up to produce mph rather than the motor???? __________________ 84 gt350 89 lx vert 92 lincoln lsc. All Forced ( one way or another)

04-15-2003, 10:51 AM	#3
Dark_5.0 Registered Member Join Date: Apr 2001 Location: Staging lane Posts: 4,337	Obviously something is wrong your car is about 7mph short of whereit should be. Most cars pick up 20+ mph from the 1/8th to the 1/4 you only picked up 12 mph. Something aint right, __________________ 92' LX-Big brakes, Lots and lots of suspension, GT40X heads, Ported cobra intake, stock cam, Vortech SC trim. 00' Lightning-Stock 88'CRX-13 second ego killer

04-15-2003, 12:19 PM	#4
fiveohpatrol I'd rather be basketweaving Join Date: Feb 2000 Location: Indianapolis Posts: 2,551	Sounds like a torque converter issue to me. __________________ NMRA O/C 9516 NA pumpgas stickshift 347 10.65@125.6, 6.73@100, 1.41 60ft

04-15-2003, 03:43 PM	#5
Dark_5.0 Registered Member Join Date: Apr 2001 Location: Staging lane Posts: 4,337	With that 1/8th mile your 1/4 mile time shoulda been a 12.11 @110mph. Thats what the analyzer said __________________ 92' LX-Big brakes, Lots and lots of suspension, GT40X heads, Ported cobra intake, stock cam, Vortech SC trim. 00' Lightning-Stock 88'CRX-13 second ego killer

04-15-2003, 04:00 PM	#6
JTMunk Registered Member Join Date: Jan 2002 Location: Albion, IN Posts: 6	I talked with Harold at Dynamic Racing Trans and he thinks that the converter is not stalling high enough. He recommended at least a 4200 RPM stall. Using the footbrake, it's difficult to raise the RPMs to 2000 before it pushes the car. Harold said I should be able to foot brake it to 3000 to 3500 RPMs. PI built the converter with all of my information and said it should stall at 3500 to 3800 RPM. What do you think? I realize my 3.73 gear ratio and 28 inch tall tires are not ideal for my natural aspirated 347 but they should be close after I get a YS trim on there.

04-15-2003, 05:40 PM	#7
dragstang86 Registered Member Join Date: Sep 2002 Location: baltimore, md Posts: 220	i have a c-4 with a Performance automatic 3500 stall...with everything in my sig i had... 1.68 60ft 7.93 1/8 @ 85.65mph 12.57 1/4 @ 105.12mph I also have a 373 gear with a 28 tall tire.... __________________ 90 LX Hatchback 306, AFR 165's 58cc, E303, 1.6 roller rockers, 70mm throttle body, cobra intake, bbk fenderwell, bbk longtubes, x-pipe, flowmasters, pullies, msd 6a, crane ps-92, stock MAF sensor, electric fan, No AC, No air pump, flaming river quick ratio rack C-4, 3500 stall, 373's, aluminum driveshaft SSM Lift bars, , sub frame connectors, strut tower brace 12.57 @105.12mph w/ 1.686 60ft before bbk longtubes (with equal shorties) ----------------------------------------- 86 tube chassis coupe - the trailor queen

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