4.10 vs 4.3 in 20B N/A FC

Phoenix7 · 09-17-2008, 02:49 PM

cool, I love seeing others projects! Keep it up man.

gmonsen · 09-19-2008, 02:32 PM

It seems to me that so many people with high horsepower cars keep going for shorter gears as a way, I suppose, to accelerate faster. This is an area where I am less technically knowledgeable, but have some experience.

Higher ring and pinion gears help leverage less powerful motors. When you have the kind of power available with 20b motors (500-700+whp), you do not necessarily need higher gears. In fact going with lower ring and pinions will probably get you through the quarter quicker, though this depends a bit on the transmission. I think Carlos (CLR) runs a 3.73 ring and pinion, for example, and I can name a few others, if you give me a minute.

If you have the kind of hp and torque that these motors can produce and use the higher gears (4.1 and 4.33), you run into several issues. You get tremendous wheelspin that costs time and is hard to control and you also have to shift 3-4 times instead of twice. I think that's why the guys running in the 9's use taller gears.

I use the 3.90 rear gear, though for a different reason. I have the Quaife close ratio gear set and want more time in gears, plus, 5th gear is 1:1 instead of 0.8:1. Anyway, I just jumped in here and there may well be other reasons for considering the 4.33 gear.

Gordon

Christopher W. · 09-19-2008, 05:34 PM

I think you are right Gordon, especially with higher horsepower. But I am going to be below 400rwhp. Remember, it is a N/A... I have listen to some different theories on the subject. I figure the best way for me to make a decision is to try it first. Like I said earlier, if it isn't what I want I will just change it.

By the way, I spoke to Logan today. I am going to get my car to Defined Autoworks in the next two months. He said that I should be able to have it back by summer. That works for me...

09-19-2008, 02:32 PM	#2
gmonsen The Ancient One Join Date: Mar 2008 Location: Eastern Pennsylvania Posts: 144 Rep Power: 18	It seems to me that so many people with high horsepower cars keep going for shorter gears as a way, I suppose, to accelerate faster. This is an area where I am less technically knowledgeable, but have some experience. Higher ring and pinion gears help leverage less powerful motors. When you have the kind of power available with 20b motors (500-700+whp), you do not necessarily need higher gears. In fact going with lower ring and pinions will probably get you through the quarter quicker, though this depends a bit on the transmission. I think Carlos (CLR) runs a 3.73 ring and pinion, for example, and I can name a few others, if you give me a minute. If you have the kind of hp and torque that these motors can produce and use the higher gears (4.1 and 4.33), you run into several issues. You get tremendous wheelspin that costs time and is hard to control and you also have to shift 3-4 times instead of twice. I think that's why the guys running in the 9's use taller gears. I use the 3.90 rear gear, though for a different reason. I have the Quaife close ratio gear set and want more time in gears, plus, 5th gear is 1:1 instead of 0.8:1. Anyway, I just jumped in here and there may well be other reasons for considering the 4.33 gear. Gordon

09-19-2008, 05:34 PM	#3
Christopher W. Rotary Fan in Training Join Date: Mar 2008 Posts: 98 Rep Power: 18	I think you are right Gordon, especially with higher horsepower. But I am going to be below 400rwhp. Remember, it is a N/A... I have listen to some different theories on the subject. I figure the best way for me to make a decision is to try it first. Like I said earlier, if it isn't what I want I will just change it. By the way, I spoke to Logan today. I am going to get my car to Defined Autoworks in the next two months. He said that I should be able to have it back by summer. That works for me...