i have a gsr motor in my civic. I drive it long distance all the time.. and at times, i cruise higher than 4400 rpms, which is my vtec crossover point for a gsr. Is my motor in vtec when i drive that fast, or does vtec senses the load on an engine b4 switching to vtec??
Im really annoyed at my gsr revving so high, enough to maybe pull my tranny out just to install a 5th gear. anybody here feel the same??

 

How do you not know the answer to your own question???

 

i know it kicks in at 4400 rpms, but doesnt it also moniter the load on the engine or the throttle percentage b4 kicking into vtec?? How is that answering my own question??

 

i believe if you floor it vtec will kick in but not if you cruising. i would say to slowly press the gas pedal down when your at that speed and listen for vtec. you might her the change.

 

Yea, i think throttle position is a variable with vtec crossing over.

What are they....oil pressure, engine temp, throttle position i believe.

-Rod

 

i disagree. on my VAFC, it'll show that it is on regardless of the % the throttle is on... stock settings.

 

Its dependent upon oil pressure so it would not kick in if you were just cruising and not getting on it.

 

Driving in vtec is not bad for your engine at all. It does however mean you are driving at a high rpm, which can be bad for your engine if you do it for long extended periods. Also for vtec to kick in, you must be moving, and for a GSR, the RPM has to be over 4400 rpms. Basically all it needs it load for vtec to kick in. Throttle position does not affect if vtec kicks in or not.

The previous person said it depends on oil pressure. You are right, however at 4400 rpms, obviously there is oil pressure. Oil pressure is rpm dependant, not throttle dependant. Hope that answered your question. Also driving at 4500 rpm's isn't really that bad for your engine. Remember ITR's and Si's rev at around 5K at that speed.

 

<---wishes the GS-R came with a sixth gear.

Only real problem with cruising in VTEC is you burn more gas but really anytime you are going faster you burn more gas...

 

I have noticed that the vtec will engage at one of two points. If I am over half throttle it will engage at 4500, if I am under half throttle it will engage at 5000.

I have noticed that regardless of when it enters vtec, that it always comes out at 4500.

 

rpm, throttle position, oil pressure (on US ECUs), engine temp, and vehicle speed (over 20mph, I believe)

with some chipped ECUs and other add-ons (Field SFC, VAFC, etc), they just switch to VTEC at a set RPM and don't care about the other sensors.

Justin

 

My GSR actually gets the best gas mileage when I cruise at 80 - 85mph

 

I cruise at 80-85 when I'm feeling like a sissy, but 90-100 on many trips for extended periods of time. I don't burn any oil and I get good gas mileage. The car seems to like it.

 

mine also, apexi vafc. if im doing 90 on the hwy it will engage, but that doesnt mean anything, its just lobing the cams for the best possible fuel %. it wouldn't hurt the engine if you drove 4 hrs in vtec

 

I don't think your going to be in VTEC while cruising at 4500 rpm.

 

actually you are going to be in vtec. throttle position is not relevant. ive tested the theory out myself.

 

the only real way to know for sure is to hook up some sort of indicator light to the wire on the ECU that sends the signal to the VTEC solenoid, then see when it lights up at different throttle positions, etc.

 

throttle position is quite relative. I challenge you to, while in first gear, accelerate with your throttle at a position that is enough to rev the engine up to 5500 rpm but not enough to be more than 1/2 throttle (you should be able to acheive this at about 1/3 throttle or less), and you will audibly hear your vtec (which I can both hear a click, and since my exhaust is rather open, I can hear a tonal change in the exhaust) engage at 5000 rpm.

otherwise, under normal full throttle, or over 1/2 throttle accel, it will engage at 4500 rpm.

this is not nessisary if your exhaust is free flowing (really open).

 

Doesn't gas useage/mileage go way when you cross into VTEC? I always thought it did, but I don't remember why...

 

Go get em Jimmy!

I think you have to be in full throttle for VTEC to engage. Why dont just cruise at 25 or 50% throttle or whatever and climb up the RPM ladder and find out if you're in VTEC or not. Hope that helps.

 

The sound you hear around the 5000 rpm mark is the secondary butterflies. Good thought, but a little off. I think its actually 5200 rpm's, but i run an ITR manifold so i haven't heard that sound in quite some time.

 

I have to disagree, when i cruise at 90 (4500rpm) my car is NOT in vtec, i have a vtec controller which has a vtec light, and at cruising speed at 4500rpm the vtec is OFF as the throttle is only partially open. I have had my car (stock ECU) at almost 100mph (98 i think) cruising and vtec OFF. If your travelling on a level/flat road with no load on the engine and at only partially open throttle then the vtec will be off, and if you come to an incline/hill where you have to accelerate slightly to keep it at 90mph then more than likely vtec will engage, but at constant 90mph with no load VTEC will not be on!


[Modified by mugenracer, 4:24 AM 1/11/2003]

 

hahah.. now im really curious.. when I have time, Im going to install a vtec lite in my car just to figure this **** out.

 

With the VAFC piggyback, VTEC will engage at set RPM no matter what. This even means VTEC will engage when it's cold. You just have to be more carefull with it.

 

I don't have a v-afc.. my signature is for my 2nd car in a hatchback. My daily driven beater is a civic with a gsr motor, bone stock (except for an intake).