i have a socketed chipped ECU with custom program, and VTEC xover at 5800rpm. i installed a JUN chip, but VTEC still engages at 5800rpm. i wanted to get my VTEC xover down lower at 4800rpm

here's the setup:

1. summit racing RPM activated switch
2. SPDT auto relay

i have the RPM switch set to send a ground signal to the relay when the RPM is reached. the relay energizes and sends 12v to the VTEC soleniod.

problems of greatest concern:
- VTEC activates purely based on engine RPM. so, when the engine speed is above 4800rpm, VTEC is activated regardless of throttle position.

- when downshifting, the engine is in VTEC above 4800rpm.

- in-between shifts with the engine speed above 4800rpm, the engine is in VTEC

is this setup acceptable, or is there some potential to damage the motor? please, i need your comments and input into this.


Modified by DOHCDX at 2:58 AM 11/5/2003

 

I personally would not do it. VTEC needs a couple of things to work and it doesn't sound like your setup takes any of that into consideration. Your car needs correct oil pressure, to be warm, and to hit a certian RPM before VTEC will engage. I personally would just leave it or go get a VAFC.

 

your fine...just make sure that the temps all are on....I think what you did actually would be fine. Try it when its cold and see if vtec still works.

 

the way i see it, the engine temperature and oil pressure are things i can monitor. obviously i'm not going to drive it hard enough to get into VTEC when it's cold and i'm not drive it period if oil pressure is low.

 

Okay...it's your motor. You asked what I thought and I told you. I'm just letting you know, you have the makings of a very bad day for your motor right here. Also, why do you need your VTEC to engage lower?? Have you dyno tuned it and proven that a lower VTEC crossover point would give you more power??

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Ricey McRicerton &raquo;</TD></TR><TR><TD CLASS="quote">I personally would just leave it or go get a VAFC.</TD></TR></TABLE>

VAFC all the way.

 

You don't want your engine to shift into VTEC until you've past the point of peak torque without VTEC. With the exception of full race motors I've never seen a motor that needed to go into VTEC before 5000, and most don't need to until 5200 or 5300. Honda spent tons of money paying people to figure out the ideal VTEC crossover points on their motors, if your motor is close to stock, then trust the Honda engineers, they know what they're doing.

 

Its a good idea...say u wanna run some GSR cams on a B16...VTEC needs to be engaged. And if no VAFC or vtec controller than his idea works. Just like the spoon VTEC controller.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Ricey McRicerton &raquo;</TD></TR><TR><TD CLASS="quote">Also, why do you need your VTEC to engage lower?? </TD></TR></TABLE>

OEM p28 VTEC xover is 4400rpm. how is 4800 less than that?

my point for this thread was not for everyone to question my VTEC xover. i will take care of that. what i want to know, is in the above situations, is it bad for the motor to be in VTEC (assuming engine at normal temp and oil pressure good)?

as mentioned before, how is my setup different from the spoon controller?


Modified by DOHCDX at 12:42 PM 11/5/2003

 

VAFC deffanly

 

ahh, gsr cams on b16, you still x-over at 5200 to 5700. the reason why it kicks in so early on gsr's is the secondaries.
forget about fuel??timming???

big lobe needs different fuel/timming settings than the primary

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DOHCDX &raquo;</TD></TR><TR><TD CLASS="quote">
OEM p28 VTEC xover is 4400rpm. how is 4800 less than that? Modified by DOHCDX at 12:42 PM 11/5/2003</TD></TR></TABLE>

I'm no VTEC ecu expert, and I could'nt even tell you what any VTEC crossover point is on a B series motor. All I was getting at is that you want to drop your VTEC crossover from 5300 or so to 4800 (lower). I would personally just pony up the 150 bucks yuo can find a VAFC for and run that instead of risking damaging my motor. I have no idea how the Spoon controller works, as I have no VTEC and don't care to drop the money on the Spoon parts.

 

If I were running a OE or style ECU I wouldn't worry about a "VTEC controller" mod like this... If tuning is really needed Hondata is the way to go... The only time I use an RPM activated switch for VTEC control is when running a standalone such as FAST, etc... It's all good tho, do what you want and what works for you... Peace