Holy Crap .... 4.30's are lots of fun!
- Thread starter gixxer750
- Start date
I really did not notice a huge difference with the 4.30 but it does launch better and it basically feels like you have more power. It does rev a little higher on the freeway but not bad. Going from 3.7 to 4.3 is only about a 14% change. If it was at 3000 rpm at freeway speed with the 3.70, it would be 3420 rpm with the 4.30 gears. It is better for me because going 70 before was right in a bad rpm spot so it was not good to race from a roll whether downshifting or just stepping on it. Now I drop it into 4th and im on boost NOW and then 5th is good to faster then I want to drive anyway.
If my math is off then :tdo3:
If my math is off then :tdo3:
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wow...
well i have 4.30's in my n/a i assume there not lsd.. i also picked up a set of 3.91's out of an 88turbo i need better gas millage..
i will be dong a dyno and a 1/4 mile time with the 4.30's and one with the 3.91s so i can get a sense to how much power differnce it is..
as for the tires...
if you have a contact patch of say 4 inches by 9 inches you have roughly 36 square inches touching the ground
while if you keep the same tire size compound and company. and just went wider tire. you will have 4 inches by 11 inches, 44"s touching the ground..
now any one that knows any thing about friction can tell you this. the more Sa you have the more friction you have.
now if you inflate the tires you will lose traction and if you deflate the tires you will hook up better.
more friction = better traction ,
but yes there are tons of things that apply; compound, width, height, rim size, gears, power band ( might find a tire that grips great with your torqe form the hole, but when you stomp on it at speeds you find it breaks traction), tread patterns. road conditions(wet, cold, hot, dry, rough road, cement, brand new paved road, tar coated smooth road.) road and tire temprature, tire pressure, the rollout of the tire allso has play,
as for top fuel draggsters.. their the shit and when you start to talk about them.. it's a hole new ball park,
top fuelers have such traction proplems that they slip tripple plated clutches.. half way down the track...
for any one who knows how to launch there car knows that some wheel spin is good, but to much is worse, then none, just like the idea of abs breaking, have some tire slip but not alot, while at the same time as breaking as hard as possible, traction controll is the oposite, designed to limit torqe and engine power , but only enough to keep with in target slip rate. it has been proven that rought 10pecent sliprate will give you both the best breaking, and the best traction possible
so in other words.. if you can learn how to feather the throttle and only get a good screach from the tires or chirps when you shift, and your not laying down strips of rubber each time you race you will launch harder, accelerate faster, and be more consistant.
one last thing..
i do alot of driving, and have purchased alot of used tires, different compounds and width's,
in the rain, a skinner tire will do better since there is more force per squar inch, then a wider tire in the rain, so put wide tires on a light rwd vehical and slide in the rain,
while in snow the same wider tire helps prevent wheel slipage.
in the sand, the wider tire along with less air pressure keeps you afloat on the sand.
hope this makes sense to some of you, and i hope others agree..
well i have 4.30's in my n/a i assume there not lsd.. i also picked up a set of 3.91's out of an 88turbo i need better gas millage..
i will be dong a dyno and a 1/4 mile time with the 4.30's and one with the 3.91s so i can get a sense to how much power differnce it is..
as for the tires...
if you have a contact patch of say 4 inches by 9 inches you have roughly 36 square inches touching the ground
while if you keep the same tire size compound and company. and just went wider tire. you will have 4 inches by 11 inches, 44"s touching the ground..
now any one that knows any thing about friction can tell you this. the more Sa you have the more friction you have.
now if you inflate the tires you will lose traction and if you deflate the tires you will hook up better.
more friction = better traction ,
but yes there are tons of things that apply; compound, width, height, rim size, gears, power band ( might find a tire that grips great with your torqe form the hole, but when you stomp on it at speeds you find it breaks traction), tread patterns. road conditions(wet, cold, hot, dry, rough road, cement, brand new paved road, tar coated smooth road.) road and tire temprature, tire pressure, the rollout of the tire allso has play,
as for top fuel draggsters.. their the shit and when you start to talk about them.. it's a hole new ball park,
top fuelers have such traction proplems that they slip tripple plated clutches.. half way down the track...
for any one who knows how to launch there car knows that some wheel spin is good, but to much is worse, then none, just like the idea of abs breaking, have some tire slip but not alot, while at the same time as breaking as hard as possible, traction controll is the oposite, designed to limit torqe and engine power , but only enough to keep with in target slip rate. it has been proven that rought 10pecent sliprate will give you both the best breaking, and the best traction possible
so in other words.. if you can learn how to feather the throttle and only get a good screach from the tires or chirps when you shift, and your not laying down strips of rubber each time you race you will launch harder, accelerate faster, and be more consistant.
one last thing..
i do alot of driving, and have purchased alot of used tires, different compounds and width's,
in the rain, a skinner tire will do better since there is more force per squar inch, then a wider tire in the rain, so put wide tires on a light rwd vehical and slide in the rain,
while in snow the same wider tire helps prevent wheel slipage.
in the sand, the wider tire along with less air pressure keeps you afloat on the sand.
hope this makes sense to some of you, and i hope others agree..
i've tried using the 4.30, not for me, i dont like the higher freeway rpms. it now collects dust among other crap sitting on the side of my house. besides, that's not going to help the ever present traction issue that i have too.
outofstep said:
dont belive it, if you can prov with an example or some logic on why surface area doesn't effect static friction or rolling friction, i'd like to know.
call me crazy.. but top fuel tires are wide for a reason, and their obviously low tire presure for a larger foot print, aka more friction,
the side walls wrinkle help avoid tire spin, on take off, then like started the tires aren't very thick, so they suck up as they spin faster.
the faster they spin the taller they get, changing gear ratios slightly, but also producing less drag/friction at speeds..
it's obvious it's alot harder to break tracion at a roll, say 50mph or so instead of a dead stop or a slow roll 10-25... so since it's harder, the loss of sa' at speed's wont hurt asmuch , and they use controlled clutch slipping techniques to keep a consistant power curve to the wheels, (top fuel..)
pimptrizkit said:
Physics 101. Surface area will NEVER change the coefficient of static friction or kinetic friction or rolling friction. Frictional resistance in the force perpendicular to the normal force.
If mew_s is 0.95 for a particular tire compound, mew_s will be 0.95 whether its an inch wide or 10 miles wide.
Wider tires provide more traction because the normal force is distributed over a larger area, thus the applied torque per unit area will be smaller because it coincides with a distributed normal force. The smaller this number, the less likely it will be to overcome static/kinetic/rolling friction.
THE FRICTION NEVER CHANGED. Torque applied per unit area is what changes.
drjonez said:
Heh, I get irritated when folks talking about how surface area changes friction. But I see it allllllll the damn time. Figured I'd just end this whole debate that went on for way too many pages.
More surface area will provide more traction, but not because of a change in friction. How that surface area is shaped will provide either better longitudinal/lateral grip. Yes, wider tires will provide more traction than thinner tires. Almost universaly wider tired will provide better acceleration traction. Though a larger longitudinal patch is better, more lateral is better than none as it WILL aid in acceleration.
bigaaron said:
I am with you on this one. People tend to get over zelous about what THEY think is right. I myself in the past have been torn apart on this forum for that exact reason.....but its nothing much more than someone elseses uneducated opionion vs. mine.
Here we have braniacs ( or want to be ) battling it out over what size tire gives better traction.
Guys, there are so many different variables to which would give you better traction...you must have tons of money laying around to even start to excersize your hypothesis's....Heat, Cold, Wet, Dry, Damp, Rocky, Pebbles, Tire width, Tire Height, Tire compound, Camber, Caster, Toe, Tire Temperature, Tire pressure........
I admit, I love to be right alot....but when its boiling down to which tires give better grip......in a thread thats about limited slip differentials and rear gearing changes effecting speeds.....
come on guys. There is an easier way to research your quandries:
http://www.google.com
http://www.ask.com/
alright outofstep. thanks for clearing it up for me.
hope i didn't sound as if i was saying your wrong, i just was tring to understand where you were coming from, and you helped point it out.
hope i didn't sound as if i was saying your wrong, i just was tring to understand where you were coming from, and you helped point it out.
outofstep said:
ok, and now im terrible at explaining things, BUT, lets try. But would you say, that, in a real world situation, where an bpu turbo supra with 4.30 gears is having traction problems with cheaper 255/45 tires, that he is better off spending money getting the same brand and style in a 285/45 or is he better off getting a 255/45 in something with a better compound like kuhmo ecsta mx's or pilot sports?
You too adam? would you suggest an extra 30mm of tire width, or a much more performance oriented tire?
Ok, yes, physics laws say tire width will aid in forward traction. but in this real world example, its not practical to follow, same as the formula i posted before, which is used. doesn't really work because of the variables.
The argument about the move from Kuhmo MX's to Michelins is silly. Thats not a good example for what we are discussing. People with n/a cars and kuhmo mxs are not having traction problems because of gearing and power. 99% of people get the go fast parts and dont upgrade the supporting team. people put cheap tires on, get the mods, cant stay straight, then upgrade. the people we are talking about arent moving from kuhmo's to michelins, they are moving from Sam's club Gatorbacks to Kuhmo's.
People have over complicated this issue in my opinion. simple advice stands i think for the guys making power and can't keep straight on cheap tires, by dr's or more performance oriented ones. 99% of the people who go up in gearing or whatever, and complain the car wont stay straight, are people who spent the money on the go fast goodies and not the support mods.. i.e. tires. There is no point in making 500rwhp and not being able to go anywhere.
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Ronin2jz said:
Like I said, wider tires will pretty much always give you better traction. Just because it isn't a longitudinal contact patch, doesn't mean anything. Well, it just means it's not as "efficient" for forward acceleration. But more surface area is more surface area.
As to what is the best a wider tire with not as soft as a compound, or a skinnier one with a stickier compound. I don’t know. I don’t know where the advantage of surface area vs higher coefficient of friction will cross. I can tell you that a 235 slick will hook better than a 315 regular street tire.
How about this; just put some nice 275+ sticky tires out back and you’ll most likely be good.
No real reason to debate at what point size vs compound will yield better results. Just go big and sticky.
CTsupra
Supramania Contributor
outofstep, everything you said makes perfect sense. good explanation! my argument was beween the cost of wide wheels vs. efficiency of a longer longitudinal contact patch, and also because a member insulted my intelligence... i did say that wide wheels and tires will help, but i repeat myself.