Turbo Gear 3.40, 3.50, 3.60 or 3.70 ?
02-04-2012, 12:03 PM
#21
Do you not see my sig?? I have a 9 second TURBO car. I've done the gearing. It works my way just fine. I've had 3.42's. Went to 2.73's. Went slower. Go figure. For that power level I was at, 3.42's put me right on my peak rpm range. 2.73's ended up matching better once I turned boost up to run more mph because thats how it works, more speed equals more tire speed which is more rpm.
Turbos make torque yes, and you can use less gear and get away with it. But HP accelerates cars. If you dont believe that then you have no business posting.
Dont need load on the motor once you start using that transbrake. It will be spooled by the time you leave the line anyway so the gearing should just match the mph goals
You dont have to spin a turbo combo to the moon. Thats not what I'm saying to do. My car only sees 6000 rpm shifts! I geared somewhat close to mid 5000 rpm crossing the traps and its worked well for me.
Theory??? this is how it works man. Tires of a certain diameter with certain gearing produce rpms/mph. Its physics and true math. Not a hard concept to master.
Turbos make torque yes, and you can use less gear and get away with it. But HP accelerates cars. If you dont believe that then you have no business posting.
Dont need load on the motor once you start using that transbrake. It will be spooled by the time you leave the line anyway so the gearing should just match the mph goals
You dont have to spin a turbo combo to the moon. Thats not what I'm saying to do. My car only sees 6000 rpm shifts! I geared somewhat close to mid 5000 rpm crossing the traps and its worked well for me.
Theory??? this is how it works man. Tires of a certain diameter with certain gearing produce rpms/mph. Its physics and true math. Not a hard concept to master.
That's how it works.
02-04-2012, 12:05 PM
#22
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Oh and here's your yellow bullet information
http://www.yellowbullet.com/forum/sh...d.php?t=374678
Less gear usually is a good thing if you are having too much power off the line.
Sometimes you have other issues like tire limitations that cause you to go taller gears than what would be optimal. IF they could hook, they'd run better with more gear.
http://www.yellowbullet.com/forum/sh...d.php?t=374678
When picking a gear you need to know your hp, peak engine rpm, and weight. Figure out what mph you can run with your hp at your weight, then, pick what tire you want to use and calculate what gear gets you said mph at the engines rpm.
the 3 main things you need are rpm, tire diameter and desired mph. Then you hope you have enough hp to run it out.
we tried 4.30's because some "experts" convinced us on the rpm thing and calculators but it hit so damn hard we couldn't get it off the line like 1.40 60's. went back to the 3.90's and it ran a hell of a lot better with high 1.20 60's. switched to another gear even higher and it runs a lot better yet with mid to low 1.20's. 3300 lbs 29.5x10.5 tires.
It depends on the car and the combination! My last stock block engine, I picked up from 6.60's in the 1/8 to 6.20's changing from a 3.55 to a 4.10, with no other changes to the car(air was a little better). It had a glide in it and was not making a lot of power!
The more power you have the less gear you need. If you know what kind of mph you have the hp to push, getting to the gear is pretty straightforward. Without knowing and your shooting in the dark.
The tire/gear calcs for mph desired arent so much the problem as starting line ratio, tire diameter and convertor stall. Able to go faster than planned wont hurt ET much if only minor difference in rear gear ratio. Turbo's do like to be loaded, though too much load could slow you down.
02-04-2012, 12:57 PM
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Thanks for the arguements guys. I know how to gear a N/A strip car. I was looking for some real world experiences from LS turbo (street) car owners which is why I posted on LS1tech. I also posted on Bullet too but didn't get much over there which I suspect is because of my 4L80 "street" car combo. Powerglide non-lockup converter in a drag only car is easy compared to picking a gear for this combo. I think I'll try the 3.40 gear. I'm probably going to order a new Strange Ultra case 40 spline around $1600. A buddy of mine wants one too and I need axles, If someone else in Southwest Missouri is interested in ordering something from Strange let me know, we need a little more to get us to the next discount.
02-04-2012, 02:01 PM
#25
Do you not see my sig?? I have a 9 second TURBO car. I've done the gearing. It works my way just fine. I've had 3.42's. Went to 2.73's. Went slower. Go figure. For that power level I was at, 3.42's put me right on my peak rpm range. 2.73's ended up matching better once I turned boost up to run more mph because thats how it works, more speed equals more tire speed which is more rpm.
Turbos make torque yes, and you can use less gear and get away with it. But HP accelerates cars. If you dont believe that then you have no business posting.
Dont need load on the motor once you start using that transbrake. It will be spooled by the time you leave the line anyway so the gearing should just match the mph goals
You dont have to spin a turbo combo to the moon. Thats not what I'm saying to do. My car only sees 6000 rpm shifts! I geared somewhat close to mid 5000 rpm crossing the traps and its worked well for me.
Theory??? this is how it works man. Tires of a certain diameter with certain gearing produce rpms/mph. Its physics and true math. Not a hard concept to master.
Turbos make torque yes, and you can use less gear and get away with it. But HP accelerates cars. If you dont believe that then you have no business posting.
Dont need load on the motor once you start using that transbrake. It will be spooled by the time you leave the line anyway so the gearing should just match the mph goals
You dont have to spin a turbo combo to the moon. Thats not what I'm saying to do. My car only sees 6000 rpm shifts! I geared somewhat close to mid 5000 rpm crossing the traps and its worked well for me.
Theory??? this is how it works man. Tires of a certain diameter with certain gearing produce rpms/mph. Its physics and true math. Not a hard concept to master.
I never said your math was wrong. Just that the theory behind it was wrong.
Yes I see you have a built 402 running high 9's. That's quick, but could be much quicker. You think just because you run high 9's you cant learn anything, ever?
I will say it again, your theory is correct for a N/A car. It is not correct for a power adder application such as turbo or nitrous.
I'm sorry you dont agree, but it's the truth.
I never said the car would run like **** with this type of gearing, obviously yours moves out... But you might be surprised if you took the time to gear it to what it wants, not what you think it wants.
02-04-2012, 02:46 PM
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I never said your math was wrong. Just that the theory behind it was wrong.
Yes I see you have a built 402 running high 9's. That's quick, but could be much quicker. You think just because you run high 9's you cant learn anything, ever?
I will say it again, your theory is correct for a N/A car. It is not correct for a power adder application such as turbo or nitrous.
I'm sorry you dont agree, but it's the truth.
I never said the car would run like **** with this type of gearing, obviously yours moves out... But you might be surprised if you took the time to gear it to what it wants, not what you think it wants.
Yes I see you have a built 402 running high 9's. That's quick, but could be much quicker. You think just because you run high 9's you cant learn anything, ever?
I will say it again, your theory is correct for a N/A car. It is not correct for a power adder application such as turbo or nitrous.
I'm sorry you dont agree, but it's the truth.
I never said the car would run like **** with this type of gearing, obviously yours moves out... But you might be surprised if you took the time to gear it to what it wants, not what you think it wants.
I will disagree with you on this subject for gearing. And please stop assuming. You first assumed that i didnt have Real world results with gear changes and spout off about Theory this Theory that, my info is false. I already explained I had changed my gears and saw it went slower, mainly because I 60 foot off footbrake only with no boost. So you didnt ask me for the experience so how can you comment that my info is false and that "it doesnt work that way in the real world"??
Second, no, just because I have a high 9 sec car doesnt mean I cant learn anything else ever. Where on earth did you get that idea from? Thats why I'm on forums to learn and see what others are doing.
You claim its the truth but post no results to back that up. My car could be much faster with a trans brake, I'm only doing 1.56 60 foots with a small head/small cam combination. I have the power to go 9.4's instead of 9.8's. It wasnt meant to set records or be a race car. It was built for the street with left over parts from a street 383 I had. How would you gear it with a 5500 rpm hp peak, 6K shift point, 26" tire and Th400 trans? I already have tallest gears you could have, 2.73's. Cant get much lower than that.
Now its getting upgraded with much bigger heads/cam and new turbo system. It should have 8 second capability if it ever does see a boosted launch. Guess what, i'm gearing to match based on the desired mph it should do, but since its a street car, i'll go taller on the gears because 3 speeds and 4000 stalls with 26" tire sucks with any kind of gear. If your tune is good, and turbines are sized right you should have no problem spooling regardless of engine load. Load helps alot tho I do agree with that.
OBVIOUSLY the best gear for the combination will come from testing the gears at the track if you are shooting for BEST ET. Just like any other aspect to engine building. You play with cam timing, head valve sizes, valve job angles, different induction setups, your converters, your suspension, launch rpms, etc to extract the most out of your combination.
But if you are starting from scratch and need a place to start, gearing it this way will work good enough for now.
05-24-2012, 09:41 PM
#28
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It's time to pull the trigger on a 3rd member and I really want to buy once and over build for future power. I'm planning to order 40 spline axles and Strange Ultra case, 3.812 case, 35 spline pinion. Problem I have now is Motive Gear bought out Richmond and discontinued 3.40 gear set. So now I'm questioning at what point 35 spline pinion is necessary. They highest/tallest/numerically lowest is 3.60 35 spline pro gear. I'm convinced the car will just kill the tires with something that low.
