Question about torque converters...

[kwillymac]

We had a 1970 Camaro with a 540 BBC in it. We went to the track and the car went 10.70 @126mph. It has a TH400 4.11 spool with 30x12.5 ET Streets. The converter was a TCI Super Street fighter.

The car was shifted at 7,000 in second and third gear. It crossed the line at 6,800 rpm. The car was a lot slower then we were hoping.




My question is does this sound like a converter issue...maybe not locking up?

[Tod74]

We had a 1970 Camaro with a 540 BBC in it. We went to the track and the car went 10.70 @126mph. It has a TH400 4.11 spool with 30x12.5 ET Streets. The converter was a TCI Super Street fighter.

The car was shifted at 7,000 in second and third gear. It crossed the line at 6,800 rpm. The car was a lot slower then we were hoping.




My question is does this sound like a converter issue...maybe not locking up?

I think they will need a lot more info than you have given them.

[woodsman]

kwillymac not knowing all the specs just going by the numbers of 10.70 @126 you are getting all the converter is going to give. Now if you have a HP number that you feel does not match your ET than I would say it may be your trans but the converter is locked up. Thats JMO.

[kwillymac]

If I use the torque converter slippage calculator it says 14%. Crossing the finish line with 30" tall tires at 6,800 RPM with 4.11 gears doesn't add up with that MPH.

Engine Specs

Block GM 502
Crank Scat Crank 4.25 stroke
Rods Scat Rods
Pistons J&E 10:1 Compression
Heads Dart Pro 1 335 CNC Ported
Cam Comp Cams Roller 260/268 @.050 .714/.714 Lift
Intake Dart 4150
Carb 1000 CFM Race Demon
Distributor MSD Billet Distributor with 6AL Box
Exhaust 2 1/8 Hooker Super Comps with 3" Flowmasters

[SST4530]

Sounds like they are driving through the converter to me. I would order a converter from Hughes, Chance or ATI.

What are the 60' times?

[kwillymac]

The 60' was 1.58. Pretty bad for this combo. That was launching off the foot brake at around 2,500. Just taking it easy.

[bjuice]

I PERSONALLY would like to know how much the cars weigh's ?
and how much HP is your motor making ?
Brian

[woodsman]

kwillymac on converter slippage numbers I would not know what I was looking at. I am just going by your MPH and it is right on the money for your ET so I would say what ever slippage that you have has to be right for your ET & MPH. May be one of the guy's that knows more than I do will pipe in on there opinion if they feel my info may be wrong. From your 10.70 @ 126 your car is efficient.

[kwillymac]

I PERSONALLY would like to know how much the cars weigh's ?
and how much HP is your motor making ?
Brian The car weighed 3610 with driver at the time it was run. Unfortunately, besides the Engine Analyzer program I have it was never dynoed.

[kwillymac]

kwillymac on converter slippage numbers I would not know what I was looking at. I am just going by your MPH and it is right on the money for your ET so I would say what ever slippage that you have has to be right for your ET & MPH. May be one of the guy's that knows more than I do will pipe in on there opinion if they feel my info may be wrong. From your 10.70 @ 126 your car is efficient. I understand the MPH matches the ET. I don't understand how a 30" tall tire with 4.11 gears crossed the line at 6,800 RPM with only 126 mph.

[woodsman]

The 60' was 1.58. Pretty bad for this combo. That was launching off the foot brake at around 2,500. Just taking it easy.

Your 60' should be around the 1.49 mark.

[kwillymac]

http://img295.imageshack.us/my.php?image=00045et6.jpg

[bjuice]

The 60' was 1.58. Pretty bad for this combo. That was launching off the foot brake at around 2,500. Just taking it easy.


well that is part of your problem here.....if you get the car to leave hard and hook..lets get say 1.38 60 ft...this is 2/10th's quicker 60 ft.....which normaly means you will make another 3/10th's on the big end..meaning a full 1/2 second off your pass...now your looking at 10.20 1/4 mile passes..

i do not care who you are unless you got a super freaking power making rat monster for a motor..you gotta get the car out of the hole...

you never see any classes like 10.5, super street,PRO-STOCK. or any FAST weekend warrior just wanting to run fast as he can..running 1.60 60ft......no... you see anywhere from 0.9 thru 1.14.......you got to wake that pig up and kick her in the butt if you really want a good ET..

When is the last time you went to a PRO-STOCK, or a 10.5 practice round and watch them leave hard and kill it 1/2 track and still run a 5.30 et 1/8 or a 8.90 et 1/4 and coast thru the lights...thats what leaving hard will do for you..

i personally see nothing wrong here but the drivers foot...and to give proper infot the car is a little bit on the heavy side too...

theats the more reason the driver has got to bring it up to leaving harder..IF you want a better ET..

I WOULD LIKE TO SEE IT HAPPEN FOR YOU !


my opinion only of course


Brian

[kwillymac]

The 60' was 1.58. Pretty bad for this combo. That was launching off the foot brake at around 2,500. Just taking it easy.


well that is part of your problem here.....if you get the car to leave hard and hook..lets get say 1.38 60 ft...this is 2/10th's quicker 60 ft.....which normaly means you will make another 3/10th's on the big end..meaning a full 1/2 second off your pass...now your looking at 10.20 1/4 mile passes..

i do not care who you are unless you got a super freaking power making rat monster for a motor..you gotta get the car out of the hole...

you never see any classes like 10.5, super street,PRO-STOCK. or any FAST weekend warrior just wanting to run fast as he can..running 1.60 60ft......no... you see anywhere from 0.9 thru 1.14.......you got to wake that pig up and kick her in the butt if you really want a good ET..

When is the last time you went to a PRO-STOCK, or a 10.5 practice round and watch them leave hard and kill it 1/2 track and still run a 5.30 et 1/8 or a 8.90 et 1/4 and coast thru the lights...thats what leaving hard will do for you..

i personally see nothing wrong here but the drivers foot...and to give proper infot the car is a little bit on the heavy side too...

theats the more reason the driver has got to bring it up to leaving harder..IF you want a better ET..

I WOULD LIKE TO SEE IT HAPPEN FOR YOU !


my opinion only of course


BrianI understand the short time sucks... This is something that will be worked on. Couldn't use the tranny brake because it would spin. I guess I didn't think the MPH matched the rpm,gear, and tire size. Thanks.

[woodsman]

kwillymac I did run the numbers on your MPH but like Brian said in his post you got to go all out from point A to point B under your full power because you don't have enough motor to make up the diffrence in your MPH. You can see that in my time down below. I think if you hit it hard and she sticks you will see the 4 to 7 MPH that you are missing now.

[kwillymac]

kwillymac I did run the numbers on your MPH but like Brian said in his post you got to go all out from point A to point B under your full power because you don't have enough motor to make up the diffrence in your MPH. You can see that in my time down below. I think if you hit it hard and she sticks you will see the 4 to 7 MPH that you are missing now.I think I may have made a misleading post. The 1.58 was hooked up to the floor. It may have left at 2,500 foot braking but it was all out. It ran 10.70 three passes in a row. The last one was 125 mph.

[woodsman]

The 60' was 1.58. Pretty bad for this combo. That was launching off the foot brake at around 2,500. Just taking it easy.

OK I am stumped but going to stick with your set up sounds to me 100%. 60' time of 1.58 with car weight of 3610lb and stall of only 2500. I have to say that you are in the ball park on this set up. But if its not right I hope you find the problem and let us know what it was. Keep it safe.

[kwillymac]

The 60' was 1.58. Pretty bad for this combo. That was launching off the foot brake at around 2,500. Just taking it easy.

OK I am stumped but going to stick with your set up sounds to me 100%. 60' time of 1.58 with car weight of 3610lb and stall of only 2500. I have to say that you are in the ball park on this set up. But if its not right I hope you find the problem and let us know what it was. Keep it safe.Oh...ok I left at around 2,500. The converter is rated at 4,500 rpm.

[bjuice]

you need to be leaving anywhere from 3500 rpm up to 4500 rpm with that 540ci...the converter you possibly have may not be the converter for that motor..it depends on where it flashes etc...?...but leaving at 2500 rpm will not get the job done anyday..wheather its the car or driver....

i am not just saying this but you would be surprised at even the people on this forum that has not even come close to running in the 1.20 or 1.30 60ft range..you gotta have everything right...and if you have never been there its subject to scare the dokkie right out cha britches..NO JOKE...
EXAMPLE; i sold my 63 bug with the 406 to a local that has really never drag raced..he would take the car to local crusie inn's and haze the tires..and had a great time...i TOLD HIM.." I SAID" Buddy ( his real name) you ever take that car to the track your gonna see another side to this car"...it was my bug for 3 yrs and i ran consistant 1.29/ 1.30 60 fts..5.88/5.90 et 1/8 mile passes NO nos...
Anyhow he took it to the track one Friday night...left one time on the tranbrake..the car hooked and he LIFTED completely off the gas..his head looked like one of those little bobbing dogs in the rear seat of your car..he was on and off the gas all the way down the track.....he got back to the pitt's and never got back in the car..as a matter of fact i bought it back...


not to get off off the beatin path but i want to say this anyhow...'ANYONE CAN RUN 120 MPH"...JUST TRY DOING IT FROM A DEAD STOP THRU THE 330 FT MARK !!!!!


Brian

[SST4530]

Guy's do you think he may be reving it a bit high? That motor may make peak HP and torque closer to the 6200 - 6500 RPM range not 7000. I'm not a BB guy so I'm not sure. What do you think?

[bjuice]

blittle chances are he is closer to his hp mark around the 7k mark rather than 6k mark....i own a few of these bbc...my 632 made max hp at 7600...my 511 seems to peak at the 7000/7200 range....

6k is not even close to turning one of these big blocks power range.

thanks for the input tho..keep it coming

[SST4530]

blittle chances are he is closer to his hp mark around the 7k mark rather than 6k mark....i own a few of these bbc...my 632 made max hp at 7600...my 511 seems to peak at the 7000/7200 range....

6k is not even close to turning one of these big blocks power range.

thanks for the input tho..keep it coming

I understand these motors should be capable of running a higher RPM than 6500 range. But looking at the setup and considering it's 10:1 motor I thought that might be a bit high.

When I take into consideration that I'm running a SB 409 CI. to his 502 in a 3500 lb camaro basically the same as his with a 4.30 gear with 29x10 slicks with 8" Hughes converter and ruinning 60' ft. in the 1.35 to 1.39 range on the t-brake and 1.45 ft brake leaving at 3000 all day long and never turning more than 7000. Well, something just doesn't add up in my feeble little mind, sorry. :lol:

Also his car is lighter than mine and has 92 more cubic inches. But 4 points less compression. I know a low compression motor doesn't really make good power at a high RPM.

I think we all agree there are many variables that can affect the performance. Tune up and chassis setup come to mind. Looks like he has cal-tracs and leaf springs on the car. This could also give him problems. Nothing wrong with Cal-tracs but there is an art to making them work well.

[kwillymac]

blittle chances are he is closer to his hp mark around the 7k mark rather than 6k mark....i own a few of these bbc...my 632 made max hp at 7600...my 511 seems to peak at the 7000/7200 range....

6k is not even close to turning one of these big blocks power range.

thanks for the input tho..keep it coming

I understand these motors should be capable of running a higher RPM than 6500 range. But looking at the setup and considering it's 10:1 motor I thought that might be a bit high.

When I take into consideration that I'm running a SB 409 CI. to his 502 in a 3500 lb camaro basically the same as his with a 4.30 gear with 29x10 slicks with 8" Hughes converter and ruinning 60' ft. in the 1.35 to 1.39 range on the t-brake and 1.45 ft brake leaving at 3000 all day long and never turning more than 7000. Well, something just doesn't add up in my feeble little mind, sorry. :lol:

Also his car is lighter than mine and has 92 more cubic inches. But 4 points less compression. I know a low compression motor doesn't really make good power at a high RPM.

I think we all agree there are many variables that can affect the performance. Tune up and chassis setup come to mind. Looks like he has cal-tracs and leaf springs on the car. This could also give him problems. Nothing wrong with Cal-tracs but there is an art to making them work well.Actually it is a 540.

[SST4530]

Ok, well that makes this situation even worse, right! :wink:

Man with a 540 that thing ought to be spankin my butt. I suspect there is more to this issue than just a converter. Although the TCI wouldn't be my choice at all.