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Discussion Starter #1 (Edited)
Well here is the deal. My 60' times are killing me here. There are times that I know it is spinning a bit but there are other times it just feels like somthing is giving but it is so straight and quick its hard to tell if it is the tires. And sometimes there it feels like there is no give at all.

I was thinking the converter might be a problem it was origanly built around my last motor with nitrous. Now the car is all motor. Converter stalls around 4500 on the trans break.

The 60' times are progressivly getting worse so maybe it is the tires. Seems to be alot left though. MT ET Drags 28x10.5-15. Here are a couple of times.

1/4 mile
60 1.52
330 4.260
1/8th 6.55
mph 106.8
1000' 8.556
1/4 10.26
mph 132.5


1/8th

60' 1.538
330 4.287
1/8th 6.575
mph 107.448

I have tried different launch rpms and 60's are getting worse but 1/8 and 1/4 times are staying pretty consistant. Let me know what you think
 

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Don't expect too much sympathy, alot of guys would give their left "test T" for those 60 ft times. Inconsistent 60 ft times can be atributed to a set of tires that are past their prime. Check all your suspension components if you haven't already, everything lubed and working smoothly, no binding, anything that could contribute to inconsistent launches. Two of the biggest things to cause your problem. If your leaving off the same rpm against the t-brake, then the power at launch should be consistent, and the converter should spin up the same even if it's not the optimum match for your current combo.
 

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Yea those 60ft times are way off. With your power you should be able to get down around 1.38-1.42 depending on the weight of the car. Do you have any video of the car so we can see what it is doing.

IMO if the 60ft times are progressively getting worse then something is giving way. How many passes do you have on the transmission? On the converter? On the tires?
 

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Discussion Starter #4
Yea those 60ft times are way off. With your power you should be able to get down around 1.38-1.42 depending on the weight of the car. Do you have any video of the car so we can see what it is doing.

IMO if the 60ft times are progressively getting worse then something is giving way. How many passes do you have on the transmission? On the converter? On the tires?
Cars track weight is approx 3100

Trans is a Dynamic MM C4 with 28 runs
Converter built by Dynamic 28 runs
Tires have approx 25 runs

Video it is the black notch. I don't know if you will be able to tell anything but there are different angles.
http://s260.photobucket.com/albums/ii9/Danno43/?action=view&current=FFW410Notch.flv

People have always said it seems to leave lazy since building new comb. I am still fairly new to automatics
 

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Converter might be too tight, that is something you have to experiment with. I can't watch the video at work. But you definitely have a 9 second car as is with some converter/suspension work.
 

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best guess is trans or too tight converter, your weight is the same as mine except i am stick, consistant 1.40 to 1.42 60 ft times are the norm for my setup. i launch @ 5500 and on 150 shot, car dead hooks and runs staight. as long as all your suspension is not binding you should @ least be in the 1.40s. anti-roll bar or air-bag in the right rear might help, good luck, allen
 

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I think your tires are DONE!!!!!!

With the radial cars, and et street stuff I'm pretty familar with after about 15 passes things are heading south. (Cars are running in the mid 9's and faster)

Also converter is going to play a part. Is it making more power now than it did with the old motor and nitrous? If not, the converter is going to be too tight.

just a couple things to think about
 

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Discussion Starter #8
Thanks for the imput gents.

88gtguy- the torque converter was built around a 306 with a ton of nitrous. That combo never happened do to some issues. Ended up putting together a N/A 410w and still had new converter and trans so decided to use it.

The tires are ET Drags not Streets. This is my first run of ET Drags so alittle unfamiliar as to how long they are good for.

acproxer- I have an anti-rollbar already. I will check all suspension components out really well.

Like I said I'm still pretty new to automatics so I was just trying to get some opinions on what you all might think.
 

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Thanks for opening up this thread. I am going through similar issues right now. I am running a C4 with a transbrake and I have an n/a 408, probably making the same power as you. My 60' times are much worse, I know I am spinning off of the line, but it might be because I am not heating them up enough or there is too much tire pressure. my best pass was a [email protected] and a 1.8 60' time, which is bad. I am leaving at 4600 on the t-brake. I am stumped. I used to run a street mustang that ran an 11.77 and I had 1.49 60' time, leaving at 5000 on a 200 shot of NOS, so there's something off.

I will take some of the advice given here to check things out.

Question: How would I know if my converter is too tight? Isn't usually the case that a converter is too loose?

Thanks,
David
 

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Discussion Starter #10
David what is your converter stalling at on the T brake now?

And a side note since we seem to have similar power what is the combo you are running. Heads, intake, came, timing, comp, and fuel?

I saw on your other post that you are running 14psi in the tires. What tires are you using? If they are MT ET Drags that is low enough. MT recomends I believe 14-16psi. and they are pretty specific on the proper way to heat them up. If you are spinning really badly you might want to work on the suspension.

Right now myself and a buddy of mine are going back to some vids and slowing them down to see what is going on. I was shocked to see how off his car was and the reason he blows the tires off everytime. Mine was alittle better but suspension needs improvement. If I can I will try to load those vids up to show you what we are seeing in two totally different looking launches.
 

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It's a 5500 stall and I am launching at 4600 on a 2-step.

I am running AFR 205 heads, Victor jr. intake, a custom grind cam, i dont know the specs off the top of my head, although, I have posted them here before, 33 degrees, 11.7:1 com and 112 octane fuel.

I am running Hoosier slicks, 28x10.

David what is your converter stalling at on the T brake now?

And a side note since we seem to have similar power what is the combo you are running. Heads, intake, came, timing, comp, and fuel?

I saw on your other post that you are running 14psi in the tires. What tires are you using? If they are MT ET Drags that is low enough. MT recomends I believe 14-16psi. and they are pretty specific on the proper way to heat them up. If you are spinning really badly you might want to work on the suspension.

Right now myself and a buddy of mine are going back to some vids and slowing them down to see what is going on. I was shocked to see how off his car was and the reason he blows the tires off everytime. Mine was alittle better but suspension needs improvement. If I can I will try to load those vids up to show you what we are seeing in two totally different looking launches.
 

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Discussion Starter #12
Ok here are some slow motion vids of a decent working suspension and one thats not working at all.

First the frontend should raise. (dosn't matter how much)

second car should move forward

Third the rear should never squat, it should raise 1-2" or stay the same. This was new to me. A good working drag suspension should not squat because when it unloads you can blow the tires off. Example watch how the cobra looks like a rocking chair when it launches. That car gets down the track at about 138 mph but runs 10.5 consistant cause of the 60'


Here is a vid of the 2 different launches. Mine is the coupe and the suspension was working decent that day but I have made some bad changes since.
A vid would help you a ton if you don't know whats going on.
http://host.stangsource.com/smashedheadcat/danno and turbo launch.wmv
 
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