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vtec q

Posted: Sat Aug 04, 2012 9:12 pm
by littlefeller
ok i should remember this but i dont, does anyone know the min speed for vtec activation? :oops:

Posted: Sat Aug 04, 2012 9:16 pm
by bristol_bb4
19mph

hmm i think anyway? did do loads of reading up on it before, its either that or 25mph im sure :roll:

Posted: Sat Aug 04, 2012 9:30 pm
by littlefeller
thanks, either is good.

Posted: Sun Aug 05, 2012 2:06 am
by ziyaan
1st gear tops out about 32/5ish which is at 7800 sort of

Posted: Sun Aug 05, 2012 9:49 am
by Sailor
... which means that vtec cuts in in 1st at about 20mph.

Posted: Sun Aug 05, 2012 9:08 pm
by littlefeller
thats cool, for some reason i had 18-19mph in mind but couldnt remember exactly, i fairly sure the last time i googled it i got quite a few different points like from 16mph to 26mph but couldnt remember the exact speed,i will have a play around with my spreadsheet and get an idea what speed a m2b4 is doing at 5000rpm. though i read somewhere that the vtec point changes depending on throttle position :?

Posted: Sun Aug 05, 2012 9:36 pm
by littlefeller
:? think i need to refrase the question, what is the min speed the ecu has to see to allow vtec, thats better :D
for an m2b4 5000rpm is 25mph but the ecu will allow vtec lower than this but i dont know how low. :?

Posted: Mon Aug 06, 2012 11:19 am
by littlefeller
ok found it, its 14-16mph

Posted: Mon Aug 06, 2012 11:32 am
by bennyboy
IIRC correctly, vtec needs three factors to activate:

Oil pressure, engine up to temp
Speed over 11mph I think
Throttle - needs a certain amount, though I can't remember what :oops:

Put it this way, mine is set at 3800, and I'm over that when cruising in 5th on the motorway, but it doesn't engage until I put my put down, giving it that third criteria.

Posted: Mon Aug 06, 2012 11:57 am
by littlefeller
on an m2b4 box 15mph would be correct for no vtec in 1st with the delimiter and vtec @5000rpm, with 11mph it would be able to vtec. so it must therefore be somewhere between the two. think at 14mph and vtec @5000 it could just do it, but then maybe there is a zone rather than an exact speed, again this may take into account of throttle possision maybe. :?