Kind of an odd question.
03-09-2011, 01:48 AM
#1
Kind of an odd question. I was talkin to a buddy of mine today about my car and he asked me what my next mod was. I told him I'd like to do a set of 4.10 gears. Now he's into bikes like me so I compared it to gearing a bike. I said it's kinda like going down on the front sprocket and going up on the rear sprocket. It gives ya more bottom end oomph. Then he asks, well what kinda horsepower gain could u compare it to. For example he says. a car with 4.10's is going to out accelerate a car with 3.42's. Then he said how much more horse would the car with 3.42s need to accelerate as fast as the car with 4.10's. And I didn't really have an answer for him. Is that kind of a stupid question? What do you guys think. Kinda got me thinking...
03-09-2011, 03:31 AM
#3
Yea i kno you don't gain any more horsepower and so does he. Just thinkin in theoretical terms I guess. ie, a car with 400hp with 3.42s would accelerate as fast as a 350hp car with 4.10's. 0-60 of course. That's what he was talking about
03-09-2011, 05:47 AM
#4
Interesting question, I thought about this a little when I was thinking about gears. And kinda what I came to with my research was that on a 100% stock car I read that the right set of gears can add .1-.3 for the E.T. so HP thats around 10-30, so you could say a lid and catback?
But with modified cars it gets a whole lot more complicated because if you set the car up right and have the mods compliment each other it can be alot more. Meaning if you have a stall and cam and get gears that will work with that powerband you could easily drop .5 off you E.T.
But overall this is a lot harder to measure in terms of comparable HP because with HP you can measure it on a dyno and compare.
So if someone has a 700 HP car and they can only run 13's with it, you can still measure it with a dyno. Where as gears there really is no way to measure the performance besides getting track times. And with that comes a bunch of other variables such as driver error, weather conditions, track prep, etc. All of which will effect the final time. So it comes down to more of a guess, then an exact science, But this is a perfect example why experienced automotive enthusiasts will tell you not to get caught up with dyno numbers and overall HP, instead you should worry more about the overall performance of the car.
Which is why its kinda funny when people come on here and say "I need to know how to make a 500 HP" well if you dont have it setup right a stock car with 500 HP can get outrun by a 400 HP car with some other complementary mods and be an overall more efficient car.
But with modified cars it gets a whole lot more complicated because if you set the car up right and have the mods compliment each other it can be alot more. Meaning if you have a stall and cam and get gears that will work with that powerband you could easily drop .5 off you E.T.
But overall this is a lot harder to measure in terms of comparable HP because with HP you can measure it on a dyno and compare.
So if someone has a 700 HP car and they can only run 13's with it, you can still measure it with a dyno. Where as gears there really is no way to measure the performance besides getting track times. And with that comes a bunch of other variables such as driver error, weather conditions, track prep, etc. All of which will effect the final time. So it comes down to more of a guess, then an exact science, But this is a perfect example why experienced automotive enthusiasts will tell you not to get caught up with dyno numbers and overall HP, instead you should worry more about the overall performance of the car.
Which is why its kinda funny when people come on here and say "I need to know how to make a 500 HP" well if you dont have it setup right a stock car with 500 HP can get outrun by a 400 HP car with some other complementary mods and be an overall more efficient car.
Last edited by Starz T/A 17; 03-09-2011 at 05:56 AM.
03-09-2011, 08:07 AM
#5
Awesome post. Makes sense. Now when u say "the right gears" are u talkin 4.10s or something a little smaller, I've read that 4.10 can knock off .5 off ur ET on a stock car. So what is that? About 50ish HP on a stock car? And I agree with u, when u start heavily modding a car. All of that changes.
03-09-2011, 11:09 AM
#6
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There are other factors to consider as well. More gear means you'll need more tire to avoid wheel spin on launch.
A 3.42 geared stock LS1 car with DRs will likely run a better ET than a 4.10 geared stock LS1 car with basic all-season street tires (assuming same HP, same weight, same driver, and same conditions). So in this example, you could debate how much more horsepower the 4.10 geared car with street tires will need to eventually catch the drag radialed 3.42 car at the end, thus making up for it's traction loss at launch.
There are several parts/areas that could be debated in this same way (meaning, what amount of horsepower will a competing car need to overcome another car that has "xxx" superior part). In my example above, the part was tires. That same arguement could apply to suspension or weight reduction as well. Additionally, gears will usually show a slight *loss* on the dyno, so that makes any comparasion of this nature even harder to calculate.
Then you have roll racing situations to consider as well. I'll use the automatic cars for this example, because it's the first thing that comes to mind. A stock 2.73 auto LS1 will downshift all the way to 1st gear at up to about 37mph, while a stock 3.23 auto LS1 will only downshift to 1st at up to about 30mph. So if you're rolling at ~35mph and both go WOT, the 2.73 car is going to go back to 1st and get a big jump, while the 3.23 car will be stuck at the bottom of 2nd. Whether or not it will be able to maintain that lead all depends on how long the race goes.
In general, gears are a more important consideration for manual trans cars. For automatics, the stall speed will be of greater concern in terms of gains vs cost/work. If I was looking to get the most out of my money while building an auto LS1 for drag racing, and had a limited budget, I would MUCH rather have a stock 2.73 gear with a 3500 stall than to have a 3.73 gear with a stock stall.
A 3.42 geared stock LS1 car with DRs will likely run a better ET than a 4.10 geared stock LS1 car with basic all-season street tires (assuming same HP, same weight, same driver, and same conditions). So in this example, you could debate how much more horsepower the 4.10 geared car with street tires will need to eventually catch the drag radialed 3.42 car at the end, thus making up for it's traction loss at launch.
There are several parts/areas that could be debated in this same way (meaning, what amount of horsepower will a competing car need to overcome another car that has "xxx" superior part). In my example above, the part was tires. That same arguement could apply to suspension or weight reduction as well. Additionally, gears will usually show a slight *loss* on the dyno, so that makes any comparasion of this nature even harder to calculate.
Then you have roll racing situations to consider as well. I'll use the automatic cars for this example, because it's the first thing that comes to mind. A stock 2.73 auto LS1 will downshift all the way to 1st gear at up to about 37mph, while a stock 3.23 auto LS1 will only downshift to 1st at up to about 30mph. So if you're rolling at ~35mph and both go WOT, the 2.73 car is going to go back to 1st and get a big jump, while the 3.23 car will be stuck at the bottom of 2nd. Whether or not it will be able to maintain that lead all depends on how long the race goes.
In general, gears are a more important consideration for manual trans cars. For automatics, the stall speed will be of greater concern in terms of gains vs cost/work. If I was looking to get the most out of my money while building an auto LS1 for drag racing, and had a limited budget, I would MUCH rather have a stock 2.73 gear with a 3500 stall than to have a 3.73 gear with a stock stall.
03-09-2011, 01:58 PM
#7
What if you took driver error and traction out of the picture. Then what. Stock to stock manual cars. One with 4.10s, the other with 3.42s. 1/4 ET difference in a perfect world. I understand it's all gonna change with all the different factors. Kinda Gettin an idea of what it would feel like on the old butt dyno loL. Nice posts so far. In the bike world, it's the same way....my buddy has an 04 ZX-6 and I have a 2006 zx10. I'm geared -1 on the front and he's +1, -2. But, we still have different sprocket sizes from factory because of obvious horsepower differences. from a 1st gear roll he'll hang with me for a few seconds. At the top of first to second I pull really hard on him. Before the gears he'd stay withe thru first and bout 2nd gear shift or so I'd leave him. Granted I can't go full throttle in 1st without reaching for the sky and he can.
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03-09-2011, 04:17 PM
#8
the 2000 TA had.I think,a 'factory horsepower rating of 310 (we all know it was more than that,but I need to establish a power amount for comparison). Taking that 2000 TA M6 310hp 3.42 geared and changing the gears to 4.10s would make it 'feel' like it became a 372 horsepower rated car. This is only 'seat of the pants' ('sotp') feeling that you would get,has nothing to do with dyno or dragstrip.
03-09-2011, 07:25 PM
#10
The only problem with "feeling" power is generally people are not very accurate and let emmotions and expectations of mods influence what they feel. This can be seen when people add exhaust and they think it "feels" a lot faster then the actual power added because the cars louder. Or the best example, a lot of people after driving a LT1 think that it "feels" faster then LS1 just b/c how the powerband is, but in reality the LS1 is overall a lot better.
