How do I get rid of VTEC??? Love the bike hate the LAG

vfrlarry · 04-28-2007, 2:52 PM

I have an 03 VFR. Love the bike, got custom step headers, two bros pipe, power commander, K&N...the usual stuff. but the VTEC sucks! I hate the explosive power gain at 7000rpm. Its dangerous in turns, especially when its wet!

Has any one heard of doing a VTR engine swap?

Also need a lowering dog bone.

Thanks!

TravisL · 08-12-2007, 8:52 PM

I'm not sure about your 6th gen, but the 5th gen you can rotate the rear triangle and actually lower the rear about 3/4" for free. You'd have to do a search to find out if this applies to the 6th gen or not.

Part of the reason I went for my 99' was lack of vtec, and gear drive cams(I like the whine) plus it was cheaper

vfrdiscussion.com may prove a valuable resource for you as well, it certainly has for me. Not sure this is much you can do about the vtec though

bladeracer · 08-13-2007, 2:04 AM

I haven't been inside one yet (my brother has one) but could you simply swap the eight V-Tech lifters with four non-V-Tech lifters so all the valves work all the time? My guess is the V-Tech valves will be a different length though so you'd probably have to replace those as well. For a trial run to see if you like it you could maybe just lock the pins open somehow. If that works it'd be pretty simple to have eight longer pins made up in hardened steel. I'm surprised nobody has made a kit to do it actually.

WVFR · 08-14-2007, 2:09 PM

Quote:

Originally Posted by bladeracer

I haven't been inside one yet (my brother has one) but could you simply swap the eight V-Tech lifters with four non-V-Tech lifters so all the valves work all the time? My guess is the V-Tech valves will be a different length though so you'd probably have to replace those as well. For a trial run to see if you like it you could maybe just lock the pins open somehow. If that works it'd be pretty simple to have eight longer pins made up in hardened steel. I'm surprised nobody has made a kit to do it actually.

Or hot wire the VTEC Solenoid Valve and force the VTEC to be on at all times?

bladeracer · 08-14-2007, 2:47 PM

Possibly. I haven't looked at the actuation system. I thought it was hydraulic pressure? Didn't know it was electronic.

WVFR · 08-14-2007, 5:08 PM

Quote:

Originally Posted by bladeracer

Possibly. I haven't looked at the actuation system. I thought it was hydraulic pressure? Didn't know it was electronic.

The solenoid opens the spool valve that controls the oil flow to the slide pins in the valve lifters. The solenoid is in the wiring diagram on page 21-3 of the service manual. Pages 22-2 through 22-5 explain the VTEC operation. I wonder if we can compensate the fuel enough with a PCIII to take into account all four valves being open.

The funny thing I didn't know is that the VTEC isn't supposed to operate when the engine temp is under 65C/149F or the side stand is down.

I would love to try this on my bike and see the effects (on a dyno to adjust the PCIII) but I'm too afraid of f'ing something up since its my daily transportation. Anyone with lots of disposable income want to volunteer their bike for the experiment?

WVFR · 08-14-2007, 5:18 PM

One thing I didn't think about was: How do we trick the ECU into firing the other two injectors below the VTEC threshold?

bladeracer · 08-14-2007, 6:40 PM

I wouldn't worry about them initially as they might not even make a noticable difference. There's plenty of bikes with single injectors putting out more power than VFR's...
I guess there's a signal from the tach to the ECU that you could probably wire a resistor into to indicates 6800+ rpm?

veefer800canuck · 08-23-2007, 5:51 AM

Quote:

Originally Posted by WVFR

One thing I didn't think about was: How do we trick the ECU into firing the other two injectors below the VTEC threshold?

Erm, every VFR800 from 1998 to present has only 4 injectors, 1 per cylinder.

So all injectors on a VTEC VFR are firing all the time, regardless of VTEC operation.

Easiest way would be to jumper out the VTEC solenoid as already mentioned, to trick the VTEC valves into remaining open 100% of the time, then add a PC III to fix the fueling throughout the RPM range.

I said easiest, but AFAIK, nobody has done this and I have no idea how the bike would respond or if it would work safely over the lifespan of the motor.

WVFR · 08-23-2007, 10:34 AM

Quote:

Originally Posted by veefer800canuck

Erm, every VFR800 from 1998 to present has only 4 injectors, 1 per cylinder.

So all injectors on a VTEC VFR are firing all the time, regardless of VTEC operation.

Easiest way would be to jumper out the VTEC solenoid as already mentioned, to trick the VTEC valves into remaining open 100% of the time, then add a PC III to fix the fueling throughout the RPM range.

I said easiest, but AFAIK, nobody has done this and I have no idea how the bike would respond or if it would work safely over the lifespan of the motor.

My bad. I thought there was one per intake port. Does make things easier though.