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Discussion Starter · #1 ·
Hi guy!

My car is civic EK3 vtec - 2000, its my drag car and office car to. This is the set up that I am running now: K&N corn filter, shaved the head, removed 1 layer from gasket, port & polish, adjustable cam pulley, total seal piston rings, board out a B16 throttle body and the intake manifold to match, EG8 exhaust manifold, a straight through 2inch pipe with a apexi barrel, ECU tuned and chipped, EG8 gear box with a close ratio 3,4,5 and a 4.8 final drive.

But the gear box is way to close and I am just reving like a bitch and not getting maximum power. So now i have two options to go with on my gear box.

1)EG8 gear box with close ratio 3rd, 4th and 5th with the standard final drive 4.2.
2)EG8 gear box with the standard gear whiles and a 4.4 or 4.8 final drive.

Which one of these do you’ll guys think will give me the optimum torque and speed in a ¼ mile.
 

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This is something you should base your decision on math, not the opinions of internet surfers. First, you need to get yourself a dyno plot of your engine so you actually know where your peak torque is and how wide (or narrow...) your powerband is.

What is your redline set at? What diameter are the tires you race with? Use those figures along with your final drive ratio and each gear ratio (or potential gear ratio) to calculate top speed in each gear. Changing gears won't change the torque output of your engine. Shorter gears amplify torque more and help you reach the powerband quicker, but allow less time in the powerband per gear and lower top speed of each gear, which can sometimes mean extra shifts in the 1/4-mile. But if they are too long of gears you can fall out of the powerband between shifts, especially with VTEC, so you don't want that either. You should be able to calculate what RPM you will be at for each gearshift also, so make sure you stay above VTEC point when shifting at redline for all the gears you will use during a race.

I'm not a drag expert, but with the combinations of gearing you have available, and the power level of your motor, I'd say you should shoot for crossing the traps right at redline in 4th. If you're a quick shifter...more shifts is more time power isn't going to the ground.
 

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Discussion Starter · #3 ·
Hi klungemonger,

I am from Sri Lanka and unfortunately we don’t have a dyno over here, so that’s why I am asking you guys over there for advice and help or I will have to remove and try each set up. We just play it by ear and go on how the car feels on each mod or change and rely on theories a lot.

Man you are so right on the gearing and being out of the power band. Actually with this gear set up I am falling only 1000-800 revs when shift and my cut off is at 9000. But I don’t take it all the way, I shift at 8.5 and fall only to about 7000 the most. i feel that there is power only up to 8.5 and that’s also because of the cam pulley being retarded by 3 degrees. So basically I feel on 2, 3, 4 gears I am out of the power ban totally ya and I use 14/55/195 semi slicks to drag.

So basically if a go with the standard EG8 gear box and may be the 4.4 final drive, I should have an edge over the other and be able to get the max power ya.
 

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Discussion Starter · #5 ·
I am running D15 engine, which is the standard one that comes in the EK3. man I have decided to go with the standard EG8 gear box with the 4.8 final drive which I am having now, so then I will have a better lunch and clime the gears faster than others to have a edge.
 

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stock cam d15 starts to fall flat on its face(loose ALOT of power) at around 7000rpm. I would be shifting at 7200-7500rpm if ou have the stock cam, reving any higher is pointles and is actualy slowing you down

http://www.akmee.com/sohc-vtec/

good link, has a graph of a z6(close to your engine) with and without a cam in it.
 

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Discussion Starter · #9 ·
Hey man! thanks so much, that was very useful.

i have done a little work on the head and have power you could say up to about 8, but that's just on the feel of the car that i say that. i know a high lift cam (stage 2) will do the trick, but just can't because have to do my day to day running as well.

Please do help me out with what ever infor you'll got. much appreciated.
 
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