you guys know if there are any consequences or damaging effects that can occur over time from having a vtec point set lower? i.e. 4400rpm or 5300rpm?

btw, stock USDM 00-01 type R cams on stock b18c5 motor with i/h/e

 

Car will be slower in most cases.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by b19coupe &raquo;</TD></TR><TR><TD CLASS="quote">Car will be slower in most cases.</TD></TR></TABLE>


How do you figure? There are a few cars that I know of making a lot of power with a low vtec xover.

poorer gas mileage would be a consequence though

 

On stock cams, primary/secondary lobes generally produce more power below ~4500 rpms...so setting the VTEC engagement somewhere above that mark could net you a few midrange ponies.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by b19coupe &raquo;</TD></TR><TR><TD CLASS="quote">Car will be slower in most cases.</TD></TR></TABLE>

how low are you talking about? 4500 is nice for ITRs with bolt on's in my experience, but it depends on the bolt ons/modifications too.

 

being turbo, I actually lost a hell of a lot of torque when my VTEC controller was set too low (4000rpms) the dyno graph showed a 25whp drop after VTEC engaged and then a 75whp spike at 5000rpms...very scarey feeling ...When I put it 5000rpms it fel much better!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MiraiZ &raquo;</TD></TR><TR><TD CLASS="quote">being turbo, I actually lost a hell of a lot of torque when my VTEC controller was set too low (4000rpms) the dyno graph showed a 25whp drop after VTEC engaged and then a 75whp spike at 5000rpms...very scarey feeling...When I put it 5000rpms it fel much better!</TD></TR></TABLE>

lol like I said.. depends on the mods

 

3500 vtec
that means u hitting vtec in all gears haha

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by George Knighton &raquo;</TD></TR><TR><TD CLASS="quote">

Say hello to 3500 RPM VTEC.

</TD></TR></TABLE>
This is a very special case. This car was tuned to a tee. Joe blow on the street with his stock type-R will lose mid-range with VTEC at 3500 rpm. There are always exceptions, that's why I said "most cases". I gotta take my hat off to SGT on that one.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by IN2VTEC &raquo;</TD></TR><TR><TD CLASS="quote">you guys know if there are any consequences or damaging effects that can occur over time from having a vtec point set lower? </TD></TR></TABLE>

My mustang runs a big cam at all rpms. It doesnt hurt anything that I know of.
Maybe more stress on the timing belt.

 

My question here is, dont you think honda/acura would have set the VTEC point lower if they though it would make the car perform better??

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by TypeR 01 886 &raquo;</TD></TR><TR><TD CLASS="quote">My question here is, dont you think honda/acura would have set the VTEC point lower if they though it would make the car perform better??</TD></TR></TABLE>

I think Honda had a good reason for a stock 5700 rpm xover. But after mods, and sometimes stock, the ITR needs a lower Xover to get rid of the large tq dip. BUT, t is fun having it set at 5700 rpm or higer with bolt ons...really makes a good kick with that 10hp+ jump when it hits.

 

When I dynoed mine with JDM Mugen header, greddy pe exhaust, aem cai, and a vafc. Setting the vtec point at 4500 rpm made the most power and smoothest transition. But you need the vafc to tune the fuel when you do this.

AW

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by TypeR 01 886 &raquo;</TD></TR><TR><TD CLASS="quote">My question here is, dont you think honda/acura would have set the VTEC point lower if they though it would make the car perform better??</TD></TR></TABLE>

don't forget that although it's a race-car-in-a-box it's still a production car, a car that needs selling points like gas milage...

 

you cannot just set the Vtec anywhere you want. there is a reason it is around 5700 rpm. you need enough oil pressure , if you open the vtec too low, you do not have enough oil pressure , and could damage the motor.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by IN2VTEC &raquo;</TD></TR><TR><TD CLASS="quote">any consequences in setting vtec point lower?</TD></TR></TABLE>
with my car lowering it helped smooth out the torque output of the motor.
~5100 or so.

the transition is hardly noticable.

 

George: Don't worry about it. It has plenty of oil pressure by 3000rpm, let alone the 4000-5000 most people use. Let's know forget the ITR motor and GSR motor share the same block and some other parts and the factory VTEC xover for a GS-R is 4400. I would be shocked if he found anything but some people posting about it and therefore took it as the gospel truth.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by b19coupe &raquo;</TD></TR><TR><TD CLASS="quote">
This is a very special case. This car was tuned to a tee. Joe blow on the street with his stock type-R will lose mid-range with VTEC at 3500 rpm. There are always exceptions, that's why I said "most cases". I gotta take my hat off to SGT on that one.</TD></TR></TABLE>

It reallys isn't all that special of a case.

Say I drive out to VA and get my car tuned by Steve. I say 'I want a graph like George's', and i have somewhat similar mods. Done. Then someone else asks another hondata tuner to do something similar. Suddenly more than a handful of people have a really low VTEC xover.

I think it is more correct to say: you will lose power with a low vtec xover unless the tuning is done very well. (you obviously can't do this with a vafc/vtec controller)

 

Okay being intrigued reading this post... Can i set my vtec x/over points lower than 5700??? with aem,jdmheader,carsoundcat,and exhaust?

if so where should you set the VTEC IN and OUT ??? oh i also have VAFC.

 

You can set your vtec xover with a VAFC within a few 100 RPM's of the stock crossover.

If you stray too far, it won't work so well.

You need full tuning capability to set your vtec xover where ever you want... it requires much more a/f adjustability than the VAFC can give you.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Type R 2c &raquo;</TD></TR><TR><TD CLASS="quote">Okay being intrigued reading this post... Can i set my vtec x/over points lower than 5700??? with aem,jdmheader,carsoundcat,and exhaust?

</TD></TR></TABLE>

Will mentioned he had good results with lowering it to "5100 or so" Give it a shot, but you really need to dyno it to get the best results for your app.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Chris N &raquo;</TD></TR><TR><TD CLASS="quote">

It reallys isn't all that special of a case.

Say I drive out to VA and get my car tuned by Steve. I say 'I want a graph like George's', and i have somewhat similar mods. Done. Then someone else asks another hondata tuner to do something similar. Suddenly more than a handful of people have a really low VTEC xover.

I think it is more correct to say: you will lose power with a low vtec xover unless the tuning is done very well. (you obviously can't do this with a vafc/vtec controller)</TD></TR></TABLE>


Chris...I'll have to disagree with you on that one...when using a vtec point as low as 3,500rpm like George(and myself, 3,300rpm), it's more of a choice of parts that work well with each other. The tuning is secondary, yes it does take a decent tuner that understands what they're doing to produce a nice and clean torque map, but the biggest variable within the whole combination is still the proper selection of parts that work in harmony with each other.

"Normal" bolt-ons with stock cams and a VAFC/Hondata like a vtec crossover of ~4,300-4,750 on an NA motor, jackson s/c cars like even lower. There isn't a "magic" crossover point, but with a little experimentation on a dyno you can find where it works best.

Austin

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Austin &raquo;</TD></TR><TR><TD CLASS="quote">


Chris...I'll have to disagree with you on that one...when using a vtec point as low as 3,500rpm like George(and myself, 3,300rpm), it's more of a choice of parts that work well with each other. The tuning is secondary, yes it does take a decent tuner that understands what they're doing to produce a nice and clean torque map, but the biggest variable within the whole combination is still the proper selection of parts that work in harmony with each other.

"Normal" bolt-ons with stock cams and a VAFC/Hondata like a vtec crossover of ~4,300-4,750 on an NA motor, jackson s/c cars like even lower. There isn't a "magic" crossover point, but with a little experimentation on a dyno you can find where it works best.

Austin</TD></TR></TABLE>

Austin,
I agree with you. My fault for not being more clear. Actually, my fault for posting my opinion/thoughts without thinking it all out thoroughly. Thanks for clarifying/clearing.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Type R 2c &raquo;</TD></TR><TR><TD CLASS="quote">Okay being intrigued reading this post... Can i set my vtec x/over points lower than 5700??? with aem,jdmheader,carsoundcat,and exhaust?

if so where should you set the VTEC IN and OUT ??? oh i also have VAFC.</TD></TR></TABLE>
I think you should go to a dyno Louise...
OH.. and I have a vtec xover at 4600. I have no vtec spike and a reletivly flat a/f ratio too. I need to get some hondata action and some SGT magic to hit my goal.
I actually improved dropping vtec.... too bad i am close to maxing out my injectors and the vafc dosn't do too good of job adding fuel.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by OK &raquo;</TD></TR><TR><TD CLASS="quote">you cannot just set the Vtec anywhere you want. there is a reason it is around 5700 rpm. you need enough oil pressure , if you open the vtec too low, you do not have enough oil pressure , and could damage the motor.</TD></TR></TABLE>

3000rpm here for maximum torque, and I don't have an oil pressure problem.