is it possible to adjust vtec engagement?

Hi there....

I've got a dc2r and as you guys know, vtec comes in fairly late at 5700rpm. Just wondering if there is any way to adjust this so it comes in earlier, eg 4000rpm. I know there are products such as vtec controllers to adjust it, but does that really make a difference? Vtec controllers basically tell the ecu to work a little differently, but if the hardware, eg cams are not designed to engage at that rpm, how can that work?

If anyone has got a similar setup to what i'm after, eg vtec @ 4000rpm, please let me know...thanks

why would u want to change the engagment of vtec anyway ?? dont you trust honda engineers? i really think its a bad idea IMO ..

i'm just curious.... because I used to drive a 180sx and the turbo kicks in at 3000rpm.... now drive a dc2r, 5700rpm seems very late.... it would be nice if it kicked in much earlier

you can , with a aftermarket ECU or piggy back computer. But unless the engine is moddified for this change in "engagement" why bother ?
As mentioned , Honda engineers developed the VTEC crossover at that exact point for a specific reason...leave it be.

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Originally Posted by teggiboy

i'm just curious.... because I used to drive a 180sx and the turbo kicks in at 3000rpm.... now drive a dc2r, 5700rpm seems very late.... it would be nice if it kicked in much earlier

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Welcome to the world of highly tuned NA's - where peak power is near the rev-limit and peak torque is near VTEC engagement point. Very different power delivery from turbo as you've noticed - you don't like the VTEC engagement - but it's set at that point to match the car.

You're in an R... so my suggestion - don't touch it - unless you know what you're doing. Chances are, you'll lose power. :thumbdwn:

Understand the car, and change your driving style accordingly - and you'll be rewarded :thumbsup:

thanks for the feedback guys.... i agree... if honda designed this machine to have vtec come in at 5700rpm for optimal performance, then best not to touch it

If your engines stock, you don't need one.

understand that lowering vtec like you want to will cause a SIGNIFICANT loss of power. The engagement occurs where one cam becomes more efficient than the other. It's not like the car makes more power with vtec engaged, and it's just held off for economy purposes.

Yeh, unless modded, leave it as is.
VTEC isnt like a turbo spool where the lower it "kicks in" the better.
Jst search round the Integra and the Noob forum for related threads and you'll get a better understanding of the matter :)

just curious but is there a time where u would ever lower ur vtec point, i dont think so?, i know of ppl making the engines rev to 10k, but in that case u would increase rpm which vtec kicks in, cause vtec is only efficent for a certain amount of rpm

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Originally Posted by czy_sol87

just curious but is there a time where u would ever lower ur vtec point, i dont think so?, i know of ppl making the engines rev to 10k, but in that case u would increase rpm which vtec kicks in, cause vtec is only efficent for a certain amount of rpm

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It doesn't work that way. Read up on what vtec really is and you'll understand why.

thats what im tryin to say
u would never lower ur vtec point would u

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Originally Posted by czy_sol87

thats what im tryin to say
u would never lower ur vtec point would u

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You would alter the cam change point if you altered the air/fuel ratios and ignition timing for your mods and 98 octane petrol. Usually you are then able to use highcam at a lower rpm without losing power from stock. That's what the hondata reflash does.

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Originally Posted by aaronng

You would alter the cam change point if you altered the air/fuel ratios and ignition timing for your mods and 98 octane petrol. Usually you are then able to use highcam at a lower rpm without losing power from stock. That's what the hondata reflash does.

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that's not really when you would change it... changing the a/f or igntion timing isn't going to make much difference there.

You're going to change vtec engagement when you alter the flow characteristics of the motor significantly. Forced induction, high comp n/a set up, different cams, etc. Pretty serious modifications are required.

also, if u change the timing, u will mess up torque numbers throughout ur revs

VTEC engines are known to have the flatted torque curves

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Originally Posted by saxman

that's not really when you would change it... changing the a/f or igntion timing isn't going to make much difference there.

You're going to change vtec engagement when you alter the flow characteristics of the motor significantly. Forced induction, high comp n/a set up, different cams, etc. Pretty serious modifications are required.

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Stock honda maps are pretty conservative. Here in Australia, they are set to run 95 RON (which is 91 PON over in the States). We do have 98 RON (93 PON) here as well and most of us use 98 all the time. So there is an avenue for leaning out the mixture while avoiding predetonation (although you'd have to make sure combustion temperatures don't go too high). I'm not talking about big power through cams or F/I though, just a small increase, especially in mid-range RPM.

Isn't this what Hondata has been doing with their reflashes anyway?

I'm not saying that power can't be found by tuning the a/f or ignition timing, just that doing so isn't changing the flow characteristics of the motor, so those changes don't justify an alteration of vtec engagement. It's when you're changing the air side of things that this comes into play.

so basically there is no point purchasing a vtec controler unless ur car is heavily modified?

Even then ,if u got the cash to heavily modify,then for a few hundred dollars more get an aftermarket ecu upgrade & leave the vafc on the shelf.

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Originally Posted by Civic^^

so basically there is no point purchasing a vtec controler unless ur car is heavily modified?

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only reason to ever buy one is if you just want something pretty and bling bling for in your car. As a tuning tool, they're a big waste of time.

THIS IS WHAT YOU DO IF YOU BUY A VTEC CONTROLLER FOR A STOCK MOTOR!

http://img166.imageshack.us/img166/777/toiletaf7.gif

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Originally Posted by teggiboy

i'm just curious.... because I used to drive a 180sx and the turbo kicks in at 3000rpm.... now drive a dc2r, 5700rpm seems very late.... it would be nice if it kicked in much earlier

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pfft as if vtec is like boost.
vtec = just sound

LOL :p

vtec is over rated.
boost is alot better.

For some reason,VTEC kicks in at approximately 4,000 RPM's... I recently changed my CAI to a K&N and it literally roars and you can feel the pull in G-force at 4,000 RPM... I don't know if this is good or not, but damn, 4k is perfect for me!

When i bought my DC2R it had a Apexi SAFC and Field FC. The Field was used to alter VTEC crossover.

The crossover was set to 4500. I changed the crossover to 5600rpm and it made a whole world of difference. I am not someone that usually can feel the difference in power from a small mod, like new pod air filter etc. But changing the crossover to stock bought a smile to my face.

I have actually now made some money, sold the SAFC and the Field and gone back to stock. Piggy backs not worth it.

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Originally Posted by Honda Enthusiast

For some reason,VTEC kicks in at approximately 4,000 RPM's... I recently changed my CAI to a K&N and it literally roars and you can feel the pull in G-force at 4,000 RPM... I don't know if this is good or not, but damn, 4k is perfect for me!

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did you shit your pants?

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Originally Posted by Honda Enthusiast

For some reason,VTEC kicks in at approximately 4,000 RPM's... I recently changed my CAI to a K&N and it literally roars and you can feel the pull in G-force at 4,000 RPM... I don't know if this is good or not, but damn, 4k is perfect for me!

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imagine how it'd feel if it was set properly! Then you could really see what kind of power your car makes.

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Originally Posted by saxman

imagine how it'd feel if it was set properly! Then you could really see what kind of power your car makes.

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Exactly. Which I experienced in my car from changing it from 4500 to stock 5600rpm.

why do big companies still make vtec controllers? surely they have to have some sort of use?

because for racing, people usually dont use stock engines, which means that stock crossover points won't be effective for motors with different power delivery and airflow characteristics.

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Originally Posted by xtercii

why do big companies still make vtec controllers? surely they have to have some sort of use?

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make money :p ppl like teggiboy would of brought one LOL jks ....

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Originally Posted by xtercii

why do big companies still make vtec controllers? surely they have to have some sort of use?

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because people purchase them.

Same reason that a lot of other crap for cars is made.


it's certainly not for racing, or people with serious engine modifications, because those people use real ecus that are capable of making real changes.