This is wheel hop, sorry I dont have the technical description.
http://www.youtube.com/watch?v=DOVtnAZYBgM&feature=related
http://www.youtube.com/watch?v=DOVtnAZYBgM&feature=related
Another 7.5 topic
- Thread starter moose
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with a 4 speed atuo a 3.42 gear is good but you can step up to a 3.73 gear but...again whats the car for? unless its out and out racing i wouldnt worry too much.
yeah the 3.42 is available for the 7.5. richmond gear makes them up to 4.56 for the 7.5.
http://www.richmondgear.com/07pdfs/RG9.pdf
there's the PDF page showing you all the gears they have. wll you have to do is determine your carrier. its series 2 or 3. i forgot which is which but you can just get another diff of the same carrier as the ring and pinion set you get and you should be fine.
BTW they have a culculator http://www.richmondgear.com/101032.html
as long as you know what the final gear is and your tire height you can compare your current gear and whatever MPH you like and then compare it to the gears you are thinking of getting.
i personally will probably use a 3.08 or 3.23 gear since i dont have an overdrive. but i might get one one day.
Transmission 1st Gear 2nd Gear 3rd Gear 4th Gear OD
Turbo 350 2.52 1.52 1 N/A
Turbo 400 2.48 1.48 1 N/A
2004R 2.74 1.57 1 0.67
700R4 /4L60 3.06 1.63 1 0.7
4L80E 2.48 1.48 1 0.57
just in case anyone wanted to know their gearing for their automatic transmission.
with a 26 inch tire, 65 MPH, with an OD gear of .7 you'll run 2K RPM
with the same inputs but with a 3.73 gear you'll run 2200 RPM. doesnt sound like much but depending on your set up that extra 200 RPM can eat gas up quickly. but depending on your engine may be in the sweet spot for your torque curve, allowing you to mash the pedal and kick it down into 3rd and pass someone easily.
and for kicks i did it with a 4.11 gear and the RPM is still a relatively low 2400 RPM. the overdrives make much higher gears possible.
now lets consider the first gear and rear gear ratio...basically multiply the two numbers and you get another number. generally around a 9-10 is good for street use, 11 and above is more suited to race tracks. this is general rule of thumb, not a hard and fast rule though.
take mine for example, 2.31 gear and my 2.52 first gear= 5.82. wow thats horrible! but thats how they made the car, for gas sipping at cruising speeds. with just the addition of a 3.23 gear it changes dramatically, 8.13. that's a huge leap in performance but isnt a very wild gear. the RPMs go up quite a bit but its as far as i would go without an OD transmission, then easily i would go with a 3.42 gear at the minimum.
i run around 1900 RPM at 65 MPH with my current gear, with a 3.23: 2700. an OD is your best friend. but since my car rarely sees over 50 since we dont do highway driving with it, we'd see about 2100 RPM at 50 MPH or about 2K with a 3.08 gear.
i can go on day about gearing.
yeah the 3.42 is available for the 7.5. richmond gear makes them up to 4.56 for the 7.5.
http://www.richmondgear.com/07pdfs/RG9.pdf
there's the PDF page showing you all the gears they have. wll you have to do is determine your carrier. its series 2 or 3. i forgot which is which but you can just get another diff of the same carrier as the ring and pinion set you get and you should be fine.
BTW they have a culculator http://www.richmondgear.com/101032.html
as long as you know what the final gear is and your tire height you can compare your current gear and whatever MPH you like and then compare it to the gears you are thinking of getting.
i personally will probably use a 3.08 or 3.23 gear since i dont have an overdrive. but i might get one one day.
Transmission 1st Gear 2nd Gear 3rd Gear 4th Gear OD
Turbo 350 2.52 1.52 1 N/A
Turbo 400 2.48 1.48 1 N/A
2004R 2.74 1.57 1 0.67
700R4 /4L60 3.06 1.63 1 0.7
4L80E 2.48 1.48 1 0.57
just in case anyone wanted to know their gearing for their automatic transmission.
with a 26 inch tire, 65 MPH, with an OD gear of .7 you'll run 2K RPM
with the same inputs but with a 3.73 gear you'll run 2200 RPM. doesnt sound like much but depending on your set up that extra 200 RPM can eat gas up quickly. but depending on your engine may be in the sweet spot for your torque curve, allowing you to mash the pedal and kick it down into 3rd and pass someone easily.
and for kicks i did it with a 4.11 gear and the RPM is still a relatively low 2400 RPM. the overdrives make much higher gears possible.
now lets consider the first gear and rear gear ratio...basically multiply the two numbers and you get another number. generally around a 9-10 is good for street use, 11 and above is more suited to race tracks. this is general rule of thumb, not a hard and fast rule though.
take mine for example, 2.31 gear and my 2.52 first gear= 5.82. wow thats horrible! but thats how they made the car, for gas sipping at cruising speeds. with just the addition of a 3.23 gear it changes dramatically, 8.13. that's a huge leap in performance but isnt a very wild gear. the RPMs go up quite a bit but its as far as i would go without an OD transmission, then easily i would go with a 3.42 gear at the minimum.
i run around 1900 RPM at 65 MPH with my current gear, with a 3.23: 2700. an OD is your best friend. but since my car rarely sees over 50 since we dont do highway driving with it, we'd see about 2100 RPM at 50 MPH or about 2K with a 3.08 gear.
i can go on day about gearing.
Before I blew my 7 1/2 inch rear, I had 342's With a stick shift 4 speed. At 59 MPH I was taching about 2800 to 2900. I have a 383 & if I tried to cruise over 3000 R's The difference in fuel milage was astronomical. I kept off of the interstates & just putted around at about 55 MPH. I could get 10 to 12 MPG If I stayed out of the secondaries. - Jon
overdrives make the difference. yeah old school stuff is fun and all but ruins the MPG rather quickly and most of the stuff was made when gas was relatively cheap. in todays oil market it pays to use an OD transmission, even manuals benefit from an OD gear.
and if you do the math they can get a more aggressive gear for the rear and with the OD it will make up for it by letting you sip gas at cruising speeds. depending on your driving habits honestly.
i lay into my pedal because i cant get any kind of launch, its jsut not geared very well at all. with a better gear i can lay off the pedal some to get up to cruising speed. but an OD transmission would let me run a 3.42 while still getting comparable gas mileage.
at 70 MPH with a 2004r OD gear of .67, tire height of 26" and a rear gear of 3.42 i get just under 2100 RPM. with the same numbers but with a final gear of 1...3100 RPM. thats a huge difference, a 1000 RPM drop. just going from a 1 final gear to a .67 is significant enough to convince me to run an OD transmission in the future. that 1K RPM can make a huge difference at the pump or rather how often i have to go to the pump.
in fact if i switched to a 2004r and a 3.42 gear i can have the same RPM at any speed as i would the TH350 and the 2.31 gear but with a much better gear to launch with which is what im wanting.
and if you do the math they can get a more aggressive gear for the rear and with the OD it will make up for it by letting you sip gas at cruising speeds. depending on your driving habits honestly.
i lay into my pedal because i cant get any kind of launch, its jsut not geared very well at all. with a better gear i can lay off the pedal some to get up to cruising speed. but an OD transmission would let me run a 3.42 while still getting comparable gas mileage.
at 70 MPH with a 2004r OD gear of .67, tire height of 26" and a rear gear of 3.42 i get just under 2100 RPM. with the same numbers but with a final gear of 1...3100 RPM. thats a huge difference, a 1000 RPM drop. just going from a 1 final gear to a .67 is significant enough to convince me to run an OD transmission in the future. that 1K RPM can make a huge difference at the pump or rather how often i have to go to the pump.
in fact if i switched to a 2004r and a 3.42 gear i can have the same RPM at any speed as i would the TH350 and the 2.31 gear but with a much better gear to launch with which is what im wanting.
I'm just trying to let the original poster know what my experience with a stick shift was. He stated that he had a stick shift. I could care less what an automatic can do. I prefer " old school" - Jon
Decent power and a stick shift is gonna be about as bad as an automatic with slicks. Say goodbye to the 7.5 :lol: .
Personally without overdrive I would go with a 3.08 or maybe a 3.23 gear at most, since you say you drive on the hi-way alot.
Personally without overdrive I would go with a 3.08 or maybe a 3.23 gear at most, since you say you drive on the hi-way alot.
I cant tell you about other peoples G bodies, but in mine I did not have wheel hop. It was a stock 307 that couldnt spin the tires on dry pavement, but it would on wet pavement. When I spun the tires and power braked the car, it never had a problem with wheel hop.
As far as I new, it is a bigger problem in cars with leaf spring rear suspension. Maybe in certain situations with G bodies, you will have wheel hop but I cant tell you from personal experience. What I am saying is you might or might not have a problem with it, so you might be able to leave everything alone.
As far as I new, it is a bigger problem in cars with leaf spring rear suspension. Maybe in certain situations with G bodies, you will have wheel hop but I cant tell you from personal experience. What I am saying is you might or might not have a problem with it, so you might be able to leave everything alone.
7d8ss said:
Thanks Jon, after reading this I'm probably going to gear it lower than 3.42. Was your 7.5 stock, or did it have any upgrades? As for "old school," amen brother!
G_Body_Enthusiast, thanks for the arithmetic, seriously. I'll put the first gear/rear end equation to use once I know the first gear ratio (bad memory on this side of the WWW). And I do know the effeciency and benefits of an overdrive. I really want a 5-speed but the transmission I have is freshly rebuilt. I got it from my uncle who had planned to put it in his camaro, but his automatic went out on him. Since he didn't have the bell/fork, clutch, or pedals yet he spent the cash I gave him for the Muncie on having his auto rebuilt.
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