New wheel size & gear ratio calculator with graphic

littlefeller · Post by **littlefeller** » Wed Nov 21, 2012 1:31 pm

I'm going to look at doing some theoretical 0-60, 0-100 times etc but I want it to take into consideration gear ratios too. Finding the equations to do that could prove difficult mind.[/quote]

this wouldnt be too difficult to do, a bonus is we all drive ludes. you would need a fair jump in hp to make a noticable difference in 0-60 times, but this would also show how much difference this dropping out of vtec really makes (prob not that much in reality). it would be a fairly simple spread sheet.

A1ex · Post by **A1ex** » Wed Nov 21, 2012 1:40 pm

I've used a theoretical one before, stock lude os 7.5 on it but with my mods it's around 6.1 - 6.2 to 60. I do have the extra 43bhp tho

It would be good to link the gear ratios to the 0-60 to see the potential change from changing gear ratios, all the theoretical ones ignore gears & the lude has particuarly close gears. The guy from poland (vlad?) got 5.7 to 60 from his lude with r888's and similar power to mine where as the theoretical is saying higher...

Post by **Merlin** » Wed Nov 21, 2012 1:43 pm

littlefeller wrote:this dropping out of vtec

I don't understand the dropping out of VTEC statement

I posted a vid a page back of me driving up the main straight of Knockhill (which is uphill as well) in my stock engine'd 5th, changing gear around 7.5K each time, and remaining in VTEC (which is audible). The only time I drop out of VTEC in my 5th is during 3rd-4th when I dont screw the tits out of it. Changing gear at really high rpm solves that though.

A1ex · Post by **A1ex** » Wed Nov 21, 2012 2:02 pm

I think littlefeller is talking about the change from first to second. with top speed in first around 38-39mph & vtec in second at aroun 42-43mph.

Going back to a much older thread of yours Merlin, with my setup I can just hit 90mph in 3rd. I have 205/55/16's & an 8000rpm limiter.

Post by **Merlin** » Wed Nov 21, 2012 2:06 pm

A1ex wrote:Going back to a much older thread of yours Merlin, with my setup I can just hit 90mph in 3rd. I have 205/55/16's & an 8000rpm limiter.

Yeah that was in my track car with an Spoon ECU with no limiter, 100mph in 3rd with a M2F5

Even still I'm almost positive I remain in VTEC when 1st-2nd in my 5th. I won't have this on video as I never use 1st gear on track.

A1ex · Post by **A1ex** » Wed Nov 21, 2012 2:17 pm

8500rpm to hit 100 in 3rd with that box on stock wheels

and your vtec speeds

First gear top speed 41.4 mph
Second gear min VTEC speed 41.3 mph
Second gear top speed 70.3 mph
Third gear min VTEC speed 59.3 mph
Third gear top speed 100.8 mph
Fourth gear min VTEC speed 75.3 mph
Fourth gear top speed 127.9 mph
Fifth gear min VTEC speed 92.6 mph
Fifth gear top speed 157.5 mph

Post by **Merlin** » Wed Nov 21, 2012 2:20 pm

I am using 215/40/17 if that makes any difference? Yeah I'm above 8K rpm from what my rev counter tells me.

A1ex · Post by **A1ex** » Wed Nov 21, 2012 2:31 pm

First gear top speed 40.4 mph
Second gear min VTEC speed 40.3 mph
Second gear top speed 68.6 mph
Third gear min VTEC speed 57.8 mph
Third gear top speed 98.3 mph
Fourth gear min VTEC speed 73.4 mph
Fourth gear top speed 124.8 mph
Fifth gear min VTEC speed 90.4 mph
Fifth gear top speed 153.6 mph

corrected final drive 4.112

Ride heigh change -3.8 mm

tyre wall height 86.00 mm (100mm stock)

with 215/40/17's

A1ex · Post by **A1ex** » Wed Nov 21, 2012 7:59 pm

I've added a graph now, makes it a bit easier to read

littlefeller · Post by **littlefeller** » Thu Nov 22, 2012 7:19 am

ok this droping out of vtec isnt noticable between 1-2, otherwise everyone would be aware of it, i only noticed when i did my gear ratio spread sheet, so i got in my car and tried, i was a little suprised to see it was correct, the same as everone else i too hadnt noticed it. so i filled in the spreadsheet with all the other gearboxes and couldnt find any that did stay in vtec as stock. there were a few members here who didnt agree, so they offered to go and have a looksie, but then they never posted there findings

ummm quess they hadnt noticed either, you can get around this by reving higher but then the power is prob lower than just shifting and dropping out of vtec otherwise honda would have set the red line higher, the redline is where it is simply because from a power point of view you are better off shifting than reving higher with the stock setup. this was altered for later vtec motors so it may be a different case for some 5g engines (doesnt the civic red line at 9000 or am i thinking s2000

some folk lower ther vtec crossover, they say it smoothes out the curve getting rid of the vtec whoosh, however, the reason this happens is simply down to the motor not making the same kinda power below 5250rpm with the vtec, most belive it does because it sounds louder, but then it would sound louder as the valve timing has now changed. the loss of the vtec kick is because its now more of a gradul climb towards whoosh

its the same as running a advanced or high lift cam on a non vtec car (it wont run too well in the lower rev range untill it climbs up to the point where the new cam is best) and infact make less power untill it gets there. so this rules out lowering the vtec crossover unless you mod the engine too suit. this is a shame as it would then be possible to easly stay in vtec. idealy what we all need is infanitly variable valve timing