Picture the scene - tarmac rally car with a B16b, S300 mapped by a local Honda specialist and a greasy wet long bend.
Idealy you would keep the foot in to accelerate round the sweeping corner, but when lifting slightly to 'modulate' the power going to the wheels it kicks out of vtec, and goes from 180 ish hp to something like 130 hp faster than you can blink.
Result - lift off oversteer - and a car that continually alternates between vtec roar and low cam pur with the slightest feathering of the right foot.
So to those that know Hondata, is there a way that I can make sure that vtec stays engaged above 3800 rpm, and ignore all other parameters that would normally trip out vtec?
In the Parameters / vtec options window:
Vtec is enabled
"disable spool error check" is not
"Vtec oil pressure switch enabled" is checked. reading the notes it says that this should be 'unchecked' for jdm engines and ecus. not sure of the importance of this.
vtec window:
lower boundary is 3800rpm -3.3psi (looks like 4k on the clock)
upper boundary is 3800rpm -9psi
minimum throttle 40%
minimum speed 9 mph
minimum temp 67 degrees C
non vtec ecu window unchecked
iab (secondary intake runner) window :
iab switch point 5750 rpm , which i am sure is irrelevant.
OK, so it looks like i am perhaps backing off below 40% tps and this is the problem, but it doesn?t feel like I am lifting the peddle far at all ??? Can I set this value to 0% without issue, and control vtec purely on RPM?
My brief to the dyno operator was to optimise the tuning for tight and twisty tarmac, as I had a real problem at one of the twistier rallies last year. Typically its stages are each 5 miles of "50 yard square right, 50 yard square left" - real point and squirt stuff. On the stock CTR ECU, vtec was not coming in till 6k and I was barely managing to keep the engine on cam.
The dyno operator basically filled a hole in the stock power curve between 3700 and 6300 rpm. He created another 15ft/lb and 20 hp throughout that gap. The car now pulls a hell of a lot better, 3800 rpm was the intersection between the low and high cam plots on the dyno graph with the maps 'optimised'.
Sorry for the long post, but I would appreciate your opinions.
--------------------------------------------------------------------------------
S300vstockb16b ecu.jpg
Description: detuned top end for 97 octane pump gas
Filesize: 49.47 KB
Viewed: 3 Time(s)
Rally car EG6 B16b w/ S300.
Rally car EG6 B16b w/ S300.
You do not have the required permissions to view the files attached to this post.
