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Holding back an automatic at the tree.


hpfiend

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Hey all-

 

Trying to get as much out of the Gremlin as we can on the current combo. I really feel like I need to launch it harder but at 2000 rpm it takes too much of the accelerator pump shot to hold it there while standing on the brakes that it has a nasty dead spot. This car requires a ton of fuel to get it going without falling on its face for some reason. It has a 50cc pump in the front with a blue pump cam in position 2.

 

If I launch at 1500 no issues but I also can't get below a 1.9 60 ft. It is pulling about 101.x in the quarter. I would like to get high 12s. It was just as fast without limited slip and 2.79 gears as I didn't have to shift to third with the th350 with a manual valve body. It now has an 8.8 with LSD and 3.73s... it feels much faster but results in the same time...

 

I was thinking of holding it with the line lock? Thus requiring less gas to bring it to 2000 as the driveline wont be fighting the brakes?

 

Thanks!

Andrew

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How do I prevent it from rolling

 

A line lock is just going to use the cars brakes. Maybe I did not fully understand your question, but you are trying to find a way to get it to a certain RPM without hitting a dead spot in the peddle right?

 

The only other option I can think of would be a transbrake.

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Have you tryed leaving it at idle until the second from last bulb. Then flooring it to try and flash the converter. If you can time it where the car just about overpowers the brakes at the same time the lights drop it can yeild a stronger launch than loading it on the brake
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Transbrake is going to be best bet

 

This...

 

2-step + Transbrake

Also, I'd say if it's not a DD get rid of the TH350 and get a powerglide.

My dad's old Trans-am picked up a tenth going from a TCI TH350 to a powerglide.

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This...

 

2-step + Transbrake

Also, I'd say if it's not a DD get rid of the TH350 and get a powerglide.

My dad's old Trans-am picked up a tenth going from a TCI TH350 to a powerglide.

 

You can DD a powerglide being the final ratio is still the same. While a PG uses less hp you will lose the lower gear a 350 provides (assuming we're not talking a custom trans deal). So you may actually go slower switching to a PG.

 

Any idea on the stall of the converter? And I wouldn't use a line lock for any type of "launching". But that's just me.

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It's a 3k rpm stall. First and second are strong but third is weak. It has a 3.73 rear gear. It pulls the same et as it did with 2.79 rear gears as we didn't have to shift to third.

 

We only drive it to the track and back.

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A trick that I used to do on the Typhoon was

-on the first staging light pop the trans in Neutral

-one foot on brake the other on gas, you should feel the brake pedal come down when you rev

-pop the trans back in gear with your foot still on the brake and start to build your rpm

-let the trans drag you to the second staging line

 

I know it sounds complicate, but it's really easy. If you do it right you should be able to get the 2k rpm launch you wanted.

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This...

 

2-step + Transbrake

Also, I'd say if it's not a DD get rid of the TH350 and get a powerglide.

My dad's old Trans-am picked up a tenth going from a TCI TH350 to a powerglide.

 

The guy doesnt even have a decent converter and you call out the big guns? The converter being to tight is the starting point if you are going to buy parts

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Have you thought about a bigger stall? Either that or transbrake like others have said. The problem with using a line lock, it may be able to hold it from pushing as bad, but then you have nothing to keep from over powering the rears and spinning. Im running a tci streetfighter 3500 in my car. I can usually stall it up to 25-2700 depending on the conditions.
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The guy doesnt even have a decent converter and you call out the big guns? The converter being to tight is the starting point if you are going to buy parts

 

This.

not to mention, losing any street driveability that car had to pick up a measly tenth, is not worth it

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  • 3 weeks later...
Have you tryed leaving it at idle until the second from last bulb. Then flooring it to try and flash the converter. If you can time it where the car just about overpowers the brakes at the same time the lights drop it can yeild a stronger launch than loading it on the brake

 

^ this is how I launch, 1.47 60'. Something else to try if not a dd is to back off the accelerator pump adjustment so you don't get the pump shot until the higher launch rpm. Bring the car to the rpm you want to launch at and adjust the pump arm to 0 clearance there instead of at idle. This was covered in an old Barry Grant catalog tech section iirc.

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