10" faster than 8" ?

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JES
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10" faster than 8" ?

#1 Post by JES » Mon Aug 01, 2011 12:45 pm

Hello to all. 71 Nova 383, 11.5,254@0.050, 108 lsa mec roller 1 3/4 long tube full 3in with tail pipes th350 4.11 275/60-15DR Car has run a best of 7.031@98mph in good spring air, it runs regular 7.teens in low to mid 80's with a Jegs xhd 3800/4100 10 inch converter.
I was looking/hoping to run into the 6.xxx so I had a custom 8" converter built for street strip said to stall 4200/4400 thought to take a tenth off my time.
For similar conditions the car lost in the 60 and in the 1/8th about 1 tenth.
Driving on the street it was noticeably tighter too.
The manufacturer said this was very odd and should have run faster as intended. Nothing has changed on the car and the car runs great, no mis or other problems.
I took out the new 8" to send back, and reinstalled the 10" because of events up and coming, and I hate to run slower.
I can not give you a flash reading, because tomuch going on at the track/trying to race. I also am very new to this, as I dont get to run offten. I can say that the 10" I can hold with the brakes, to right at 4000 and with the 8" I could only hold to 3000.
The manufacturer is afraid to loosen(but they will) because they thought it would loose efectiveness.
This combo should make max torque just over 5000, for max ET should it not stall somewhere close to this? Is this all wrong for street strip?
Going over the stripe with the 10" at 98mph is just over 6000 and with the 8" at 96 it is about 5800.
Any suggestions?

JES
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Re: 10" faster than 8" ?

#2 Post by JES » Tue Aug 02, 2011 10:02 pm

Any ideas ??????? recommedations????????



thanks.

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John_Heard
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Re: 10" faster than 8" ?

#3 Post by John_Heard » Fri Aug 05, 2011 7:50 am

Well it sounds like you need to send that 8" back in to have them loosen it up.

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Bruce69Camaro
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Re: 10" faster than 8" ?

#4 Post by Bruce69Camaro » Fri Aug 05, 2011 1:18 pm

One thing that I have learned was, not to go cheap on your torque converter because this is the heart of your combination. If your motor doesn't have anything good to transport the power too, then it just isn't going to happen.

With this in mind, is the company that you got to make your custom 8" from, a good converter company or are they another company like GER or some of those other brands you can off of Ebay?

Listen to John, send it back and get it lossened up.
Those who think they know it all have no way of finding out they don't......... :scratch:

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chpcamaro
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Re: 10" faster than 8" ?

#5 Post by chpcamaro » Sat Aug 06, 2011 10:29 pm

something doesn't seem right here are you using a trans brake or foot brake? because with your combo i wouldn't think you want a 8 inch and if your foot braking it and you can get the 10 to stall to 4000 at the starting line that is one super loose 10inch. can you give us more info on the combo
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JES
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Re: 10" faster than 8" ?

#6 Post by JES » Sat Aug 06, 2011 10:38 pm

Bruce69Camaro wrote:One thing that I have learned was, not to go cheap on your torque converter because this is the heart of your combination. If your motor doesn't have anything good to transport the power too, then it just isn't going to happen.

With this in mind, is the company that you got to make your custom 8" from, a good converter company or are they another company like GER or some of those other brands you can off of Ebay?

Listen to John, send it back and get it lossened up.
The converter is an ATI. I'm sure it is good quality. Just not making my car as fast.
Thanks
Last edited by JES on Mon Aug 08, 2011 9:10 pm, edited 1 time in total.

JES
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Re: 10" faster than 8" ?

#7 Post by JES » Sat Aug 06, 2011 10:50 pm

chpcamaro wrote:something doesn't seem right here are you using a trans brake or foot brake? because with your combo i wouldn't think you want a 8 inch and if your foot braking it and you can get the 10 to stall to 4000 at the starting line that is one super loose 10inch. can you give us more info on the combo
I'm not shure what you would like to know.
I do foot brake the car. I could only get the rpm's that were quoted by holding the steering wheel with both hands, one foot on the brake and the other on the throttle.
This is before the wheels spin
I leave the line at approx 1200/1500.

The 10" is a Jegs XHD 3800/4100 Thanks John

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Marty Chance
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Re: 10" faster than 8" ?

#8 Post by Marty Chance » Tue Aug 09, 2011 6:50 am

once the 8"is restalled to flash higher the 8" will be faster. the smaller diameter and less weight take less HP to turn therefore more power makes it to the rear tires. Dont give up on your 8" , let your converter man change the flash stall and you will love it
Neal Chance Racing Converters
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JES
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Re: 10" faster than 8" ?

#9 Post by JES » Tue Aug 09, 2011 9:21 am

Marty Chance wrote:once the 8"is restalled to flash higher the 8" will be faster. the smaller diameter and less weight take less HP to turn therefore more power makes it to the rear tires. Dont give up on your 8" , let your converter man change the flash stall and you will love it

Thanks for all the replies.
Where do you think the target stall should be?
Thanks John

P.S. what do you think of the rpm's now, and what do you think they should be?
I have no data other than reading the tach as I cross the line.

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Marty Chance
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Re: 10" faster than 8" ?

#10 Post by Marty Chance » Tue Aug 09, 2011 12:18 pm

i would start with putting the stall the same as the 10" . The 8" if built right has the potential to be more effecient than the 10"
Neal Chance Racing Converters
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