what rear gear raito
#1
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Location: spring creek nv.
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what rear gear raito
i have 4;88 gears now and been told i'm to low gears for blower engine.my first blower engine.will be doing some controled gurge racing at car shows and cruises[at air ports NOT ON STREET]1/8th mile and some less.but also whant to do 1/4 at the drag strips..what gear raito should i run or can i leave what i have in car now?still building car so don't have rpm range on engine just the specs i have below..also trying to get converter built for car and they want rear gear raito before converter can be built..
CAR BUILD SPECS
540bbc/11.8 comp pistons/heads will be done by curtis[pro valve job/c-n-c ported and flowed/i think he said around 445 cc flow but don't remember if that is before or after he works on them]they are brodix 2-plus heads/roller cam with 736 lift 116 LC ;871 stage 4 blower/aly injection bird catcher w/modified square doors]mallory super maglll ign.//trans is PG with 10 disc high gear-stright cut 1;80 planitary-trans brake/4;88 rear gears/spool/32.14.5 slicks/
62 nova wagon built into a 2 door seden delivery with glass doors/front end/guted tail gate-full chassis car with M/S cage[hope to certifie to 7;50/has steel firewall and steel floor with middle trans tunnel and drive line tunnel aluminum/christ alston a-arm front end/ladder bar rear/
CAR BUILD SPECS
540bbc/11.8 comp pistons/heads will be done by curtis[pro valve job/c-n-c ported and flowed/i think he said around 445 cc flow but don't remember if that is before or after he works on them]they are brodix 2-plus heads/roller cam with 736 lift 116 LC ;871 stage 4 blower/aly injection bird catcher w/modified square doors]mallory super maglll ign.//trans is PG with 10 disc high gear-stright cut 1;80 planitary-trans brake/4;88 rear gears/spool/32.14.5 slicks/
62 nova wagon built into a 2 door seden delivery with glass doors/front end/guted tail gate-full chassis car with M/S cage[hope to certifie to 7;50/has steel firewall and steel floor with middle trans tunnel and drive line tunnel aluminum/christ alston a-arm front end/ladder bar rear/
#2
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RACING JUNKIE
Join Date: Jan 2006
Location: La.
Posts: 2,890
If you plan on running a qtr. i think you're going to need 4.10's certainly no more than 4.30's, blower motors have a tendency to come on strong on the bottom end, unlike a turbo motor, The boost is up immediately, around 3,000 rpm. I'm going with 4.30's in my Anglia but donot intend to run anything but 1/8 mi.
JMO
Zip.
JMO
Zip.
#3
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Location: spring creek nv.
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not getting any smack about the right gears here.is everyone agreeing with zip?i highly respect what he says on here but odd that no one else has agree or disagree with these gears..
#4
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Join Date: Apr 2008
Posts: 504
I always determine my or your gear ratio based on the predicted or the actual MPH you will be running at which ever finish line you are racing to.
If you had an automatic trans and thought you could make the power to run 161 to 164 MPH at the finish line and you had 102" roll tire and wanted to rev 7650 RPM in the lights 4.33 would be a good choice no mater what your power came from blown or sucked. If you think you have more than that then maybe 4.10 would be better. Only the power that your engine actually makes, its weight, tire roll out and RPM you are targeting at the stripe is known you will be guessing what one is perfect for you in the end. I hope this gives you some insite on your question.
If you had an automatic trans and thought you could make the power to run 161 to 164 MPH at the finish line and you had 102" roll tire and wanted to rev 7650 RPM in the lights 4.33 would be a good choice no mater what your power came from blown or sucked. If you think you have more than that then maybe 4.10 would be better. Only the power that your engine actually makes, its weight, tire roll out and RPM you are targeting at the stripe is known you will be guessing what one is perfect for you in the end. I hope this gives you some insite on your question.
#5
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Originally Posted by TopspeedLowet
I always determine my or your gear ratio based on the predicted or the actual MPH you will be running at which ever finish line you are racing to.
If you had an automatic trans and thought you could make the power to run 161 to 164 MPH at the finish line and you had 102" roll tire and wanted to rev 7650 RPM in the lights 4.33 would be a good choice no mater what your power came from blown or sucked. If you think you have more than that then maybe 4.10 would be better. Only the power that your engine actually makes, its weight, tire roll out and RPM you are targeting at the stripe is known you will be guessing what one is perfect for you in the end. I hope this gives you some insite on your question.
If you had an automatic trans and thought you could make the power to run 161 to 164 MPH at the finish line and you had 102" roll tire and wanted to rev 7650 RPM in the lights 4.33 would be a good choice no mater what your power came from blown or sucked. If you think you have more than that then maybe 4.10 would be better. Only the power that your engine actually makes, its weight, tire roll out and RPM you are targeting at the stripe is known you will be guessing what one is perfect for you in the end. I hope this gives you some insite on your question.
#6
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DYNO OPERATOR
Join Date: Apr 2008
Posts: 504
Welcome to the world of hot rodding. If it were easy every one would have the perfect set up every time. You will have a learning curve due to the un knowns that you don't know about your own car and combination. For some of us that is the enjoyment we get out of our sport. Sorry no crystal ball to help you with
#7
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Originally Posted by TopspeedLowet
Welcome to the world of hot rodding. If it were easy every one would have the perfect set up every time. You will have a learning curve due to the un knowns that you don't know about your own car and combination. For some of us that is the enjoyment we get out of our sport. Sorry no crystal ball to help you with
#8
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Join Date: Apr 2008
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Then put 3.90 gears in it and forget about it. Then you can tell your converter builder something that is known. The power and torque of your engine will be bigger players in your equasion reguardles what gear you end up with. You won't out grow the 3.90 gear untill you start running low 7 second quarter miles.
#9
Ratio
I agree with TopSpeedLowET. You have to set some type of goal before you start putting it together. It's more realistic to set the goal and assemble the parts after you collect input on what will get you there. JMO
#10
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Originally Posted by TopspeedLowet
Then put 3.90 gears in it and forget about it. Then you can tell your converter builder something that is known. The power and torque of your engine will be bigger players in your equasion reguardles what gear you end up with. You won't out grow the 3.90 gear untill you start running low 7 second quarter miles.