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Engine/Gearbox questions and discussion
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JayJay
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Post by JayJay » Thu Feb 02, 2012 9:27 am

I've the H22A with the M2B4 box, 205/50/15 tyres I think, maybe 205/55/15.

I can't quite remember if and when it drops out, I know 1st to 2nd it does, but it's not often I'm accelerating off in VTEC in 1st! To be honest whenever I vaguely put my foot down in 1st at the moment the wheels spin, so it's a waste of time :lol: Thin wheels and wet/icy roads :(

If the mountain road is clear later on the way home (and not too icy) I'll see what gears stay in VTEC and at what RPM I switch, but I can't guarantee how accurate the tachometer is!
Shiny wrote:I sniff dirty pants.

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littlefeller
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Post by littlefeller » Thu Feb 02, 2012 10:42 am

thanks jay, to be honest i rarely use vtec 1st or 2nd (tries to wrench the wheel out of my hands) ok, with your tyres it should be as follows (assuming a vtec activation @ 5250rpm) min speed for vtec in 2nd is 43mph, then for 3rd is 62mph.
now this is the problem according to the ratios in the list @ 7000rpm 1st is 34mph and then 58mph for second so @ 7000rpm there is no vtec for 1-2 and 2-3. but at 8000rpm 1st is 40 and 2nd is 68 so it should only fall out of vtec 1-2 with 2-3 being fine. tach acuracy may be an issue here though.
now this is the realy bummer, to get vtec 1-2 you would have to rev to 8000rpm and lower vtec to 4800rpm. but intrestingly the higher gears dont drop (closer together) as far, so i would be possible to raise ratios here (4-5) who needs to vtec in 4 or 5 anyway exept for you that is. :evil: (not fair).
one other thing we can try safely is hold revs @ 3000rpm in 2-3-4-5 it should read 2nd-25mph, 3rd- 35mph, 4th- 47mph, and 5th 62mph.
the auto is as follows
1st to 2nd changing at 7000rpm is 13mph short of vtec, 2nd to 3rd is 6mph short of vtec and worse still 3-4 is 12mph short :shock: but i know all this anyway 8-)
does this mean no one has vtec from 1-2 :shock: and a fair few (those shifting @7k) from 2-3 either :shock: :shock:
what is the std rev limit anyone?

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JayJay
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Post by JayJay » Thu Feb 02, 2012 11:13 am

That doesn't sound quite right, even when I VTEC in first (if I stop the wheels from spinning) it's only just out of VTEC when I change up to 2nd.

I'm pretty sure I'm closed to 40mph in 1st. At least I was when I had my old 17s on.
Shiny wrote:I sniff dirty pants.

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littlefeller
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Post by littlefeller » Thu Feb 02, 2012 11:19 am

littlefeller wrote:first thread from me on ld :D , although i have aslo posted this on puk as my last thread on puk :shock:
right here goes.
the senario, im traveling along in my auto lude, say im doing 65mph, if i floor it it will downshift to 3rd till it reaches around 7250rpm then shifts to 4th but falles out of vtec, but if im doing 65mph then manually shift to 3rd it will rev to say 7250rpm and i then shift it myself to 4th, but now the auto box finds a gear between 3 and 4 and stays in vtec how?
ok found the answer, its is partial and or half lock up, now question is can i influence this :?

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littlefeller
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Post by littlefeller » Thu Feb 02, 2012 11:21 am

yes but the 17 would be higher speed, though this doesnt change the ratios it does change the min speed you would need for vtec in a perticular gear.

what size tyres were on the 17s, will check the spred sheet and see what difference this makes :D

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JayJay
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Post by JayJay » Thu Feb 02, 2012 11:30 am

They were 215/45/17 I think, or 215/40/17.
Shiny wrote:I sniff dirty pants.

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littlefeller
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Post by littlefeller » Thu Feb 02, 2012 11:34 am

ok if they were 40/17, not much difference but if they were 45/17 then ther is a 3-4 mph difference in 1st @7000rpm (1st is 37mph with these tyres) but then the min speed for vtec in 2nd would also be slightly higher, supose its possible people dont notice as it would still be exellerating fast anyhow. i notice mine as its noticable louder :lol:

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littlefeller
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Post by littlefeller » Sun Feb 05, 2012 4:52 pm

hey alex, sorry didnt see your post on page 4,
thanx for testing. 67.9 for 2nd @7800rpm. but max speed for 1st comes out @ 40.3mph for vtec @5250rpm you need to be doing 45.7mph for vtec after shift, did you notice the lack of vtec or is there just too much going on :?

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Donald
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Post by Donald » Sun Feb 05, 2012 6:51 pm

I'll have a little test when the snow pisses off, but I'm pretty sure I stay in VTEC between 1st & 2nd, and if not it's such minuscule amount of time non-VTEC that you don't notice. Usually I end up getting a little spin so maybe that distracts me from noticing.

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JayJay
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Post by JayJay » Mon Feb 06, 2012 10:08 am

Oh by the way on my current wheels I can stay in VTEC between 2nd and 3rd :) Tested 8-)
Shiny wrote:I sniff dirty pants.

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