Total effect of boring throttle body and changing final drive ratio?

[Milgram]

Please correct me if I'm wrong.

 

I understand that a bored throttle body will improve low-end torque (and therefore increase FC) whilst changing your final drive ratio will improve your high-end torque (and therefore decrease FC).

 

If I were to do these two mods together, what's the final effect? Will I have both improved low- and high-end torque? Or will these be cancelled out? Also, what will happen to my FC? An overall increase, decrease or no change?

 

Thanks!

[Heeltoenoob]

Boring your TB might make your low-end worse off.

 

Changing to a higher FD makes your gear ratio closer, thus give you the feeling more a more "torquey" car. "Improve high end torque"? It's an illusion...

 

How can ppl tell you what final effect, so many variables...duh.

 

If concerned about FC, don't do the mods above. Higher FD will definitely increase overall FC.

[Watwheels]

I wonder why u wanna do such mods to your car.

 

Boring the throttle body is of no effect. The key is to change the air intake manifold to a bigger one. But it's illegal.

 

Final drive ratio thing, I dunno how u gonna mod. But I believe performance is more or less the same. Like as if u can mod a 1.6L to perform like a 1.8L or 2.0L(legally that is), every mother's son will buy a 1.6L and mod.

 

IMO save your money to get a better performing car.

[Bern2]

Can't have it both ways. Want power means FC suffers. Boring might make your low end suffer more... depending on how good your ECU is at remapping. Change Final drive will allow u to accel more quickly as gear ratio is closer but means higher speed and FC will suffer.

[Milgram]

Hmm...I was actually given the impression that a better final drive ratio (i.e., the lower the number) the lower the FC...

[Streetbumpkin]

" I wonder why u wanna do such mods to your car.

 

Boring the throttle body is of no effect. The key is to change the air intake manifold to a bigger one. But it's illegal.

 

Final drive ratio thing, I dunno how u gonna mod. But I believe performance is more or less the same. Like as if u can mod a 1.6L to perform like a 1.8L or 2.0L(legally that is), every mother's son will buy a 1.6L and mod.

 

IMO save your money to get a better performing car."

 

 

http://www.onemotoring.com.sg/publish/onem...ml#MainPar_0030

 

Air Intake manifold is classified under legal modification

 

Cheers

Edited May 22, 2007 by Streetbumpkin

[Heeltoenoob]

Depends on how you define "better"...People who want better acceleration go for a higher FD la. eg. 4.4 -> 4.7. I never heard of ppl purposely reduce FD unless they bought at modded car and it's quite undrivable to the new owner. Not to improve FC.

 

Brudder, if you really want good FC, keep the car stock, and behave your right leg. You will get the best FC the car is capable of.

[Milgram]

My understanding of FD (I'm talking about going from a higher number to a lower number) is that acceleration is better but only because high-end torque improves...meaning you are going faster at a lower rpm (at a higher gear). However, this will cause your pick up to slack (i.e., at a lower gear, especially if you are talking about moving off from a stationary position). In any case, because your are revving lighter at higher gears, FC is actually reduced (i.e., becomes better). The reverse is true - that is, if you change your FD from lower to higher number (which few ppl do), then your low-end is better (i.e., your pick up is better) but your high-end suffers. In this reverse situation, FC will increase.

 

I'm not looking to increase my FD ratio but looking to reducing it (for better high-end acceleration).

[Heeltoenoob]

What talking you...where got torque improve or worsen from changing final drive?

 

It's like saying when you change the gears on a mountain bike your leg muscles become bigger

 

Your car jus feels more torquey when you change to a bigger FD cos of the shorter gear ratios. The car revs up quicker and thus faster acceleration.

 

If you reduce your FD, might get better FC if you maintain same driving style. But you will not get better acceleration in high nor low end.

[Jtis]

I think you got the wrong concept of how it all works on your car. Maybe you need to get abit more experience on cars before attempting mods. A Final Drive is not a mod like cams and such which shifts the powerband of your engine upwards. The FD is a gearing component in the gearbox and the gearbox in general acts as a torque multiplier. So if you increase your FD, i.e. lower to higher number, you increase the torque multiplication factor. You will get better acceleration at all rpms, at the expense of top speed. If you cruise at 100km/h at 3k rpms before, you might need 4k rpms to cruise at the same speed after changing to a higher FD. Lower the FD, i.e. higher to lower number, will result in poorer acceleration in all gears at all rpms. Top speed increased. Very few ppl decrease their final drive, only ppl who wheelspins through 1st, 2nd, 3rd gear on their monster machine will reduce their FD...

[Turbonetics]

Please correct me if I'm wrong.

 

I understand that a bored throttle body will improve low-end torque (and therefore increase FC) whilst changing your final drive ratio will improve your high-end torque (and therefore decrease FC).

 

If I were to do these two mods together, what's the final effect? Will I have both improved low- and high-end torque? Or will these be cancelled out? Also, what will happen to my FC? An overall increase, decrease or no change?

 

Thanks!

 

i don't think boring of throttle body helps the low end,in fact i think the low end suffers.

changing of FD will not affect your horsepower or torque number.

higher FD have better acceleration but lower top speed which means at 100km/hr your car will be at maybe 3500rpm which is quite high and consume more petrol.

lower FD have higher top speed but accelerate slower.at 100km/hr,it can be as low as 2500rpm thus better FC.

[Milgram]

Thanks for clearing that up bro...Looks like I was given the wrong idea about FD...I was told that a lower number actually increased 0-100km/h acceleration...

[Milgram]

Good analogy Thanks!

[Turbonetics]

if we compare two same cars one with a lower FD and the other with a higher FD,the one with the higher FD(bigger number) will reach 0-100km/hr in a shorter time though their power are the same.

but for a longer drive of max speed,the one with the lower FD will win because it can reach higher top speed.

[Seanboi]

do u have any idea how much does it cost to change FD?

[Icetrap]

Please correct me if I'm wrong.

 

I understand that a bored throttle body will improve low-end torque (and therefore increase FC) whilst changing your final drive ratio will improve your high-end torque (and therefore decrease FC).

 

If I were to do these two mods together, what's the final effect? Will I have both improved low- and high-end torque? Or will these be cancelled out? Also, what will happen to my FC? An overall increase, decrease or no change?

 

Thanks!

 

By Boring your throttle body, you might get a better response. More Air + More Fuel = Better horsepower. But there is a limit to how much you can bored.

 

Final Drive only impacts on the gears, nothing to do with the engine. Like one bro has already explained

 

BTW what are you trying to do? Increase performance and fuel economy at the same time? Remember "With GREAT POWER, comes GREAT FUEL consumption"

Edited May 23, 2007 by Icetrap

[Otsego]

any1 mind telling me what is "Boring throttle body" and what its does?

[Otsego]

hmmmm that Line is so familiar