How do Vtec killer cams work?

 

two big honkin cam lobes and no mid lobe, good for stupid high compression and drag racing. they work the same way normal non vtec cams do if I am not mistaken.

 

Then how do they add so much horsepower? How does taking away Vtec help?

 

heres a post on the sound clips, https://honda-tech.com/zerothread?id=496260

 

well cam theory in a nutshell. Ok cam development has come a logn way in honda acura world esp w/ vtec....now what vtec killer cams do is take away the main bigger lobe in the middle and create bigger outer lobes..in essence taking away vtec...what this helps is the transition area....for ex. skunk2 stg1 cams have almost a regular gsr secondary lobe which helps gas mileage when your not reving the **** out of your motor, where the get there power is up top by making the larger primary lober bigger..more lift + duration usually = more power...in the case when you jump from a secondary lobe to a primary lobe there is a period of bogging...that why the stg 1's aren't so radical and the bog isnt all to bad...now the skunk2 stg 2's have a bigger secondary lobe and a huge primary lobe, which makes the idle a little less than ideal but with tunning is very streetable...stg 3's are just down right power up top of course...huge lifts and duration and w/o tunning will absolutely run like **** idling...in between the stg 2 and stg3 secondary lobes transition to the primary lobes there is a huge trasition (that why on sound clips it SCREAMS tearing into vtec)...you can see this if youve ever seen dyno plots for them...that because the bog on the crossover...so to fix the problem of the bog people move the vtec crossover higher in the rpm band, shifting the powerband in retrospect...so in turn to get the full potential out of the huge stg 2 and stg3 lobes you have to be revving pretty high 7500+...that why they consider stg2's semi streetable, and stg 3 full race...dont get me wrong w/ tuning i have seen stg 3's scream on the street but daily driving the blow goats for gas mileage etc...so to get back to you orginal question on why someone would elimnate vtec...its to eliminate the so called bog and make the trasnsition easier...in essence you eliminate the bog in between lobes...yet it doesnt change the effect of the powerband shift you still have to rev higher to get their full potential...so in essence what vtec killer cams have done is taken the skill out of configuring a smaller lobe then a trasnition to a bigger lobe out of the equation and just focused on making more power...these companies tend to be companines of non-import origin but of domestics...they know some stuff but not all about vtec...the like their big lobed cams & a rough idle....

if your looking for a street cam my suggestions are skunk2 stg 1's w/ some tuning and w/ the appropriate mods on a gsr can see upwards of 180+ w/ stock cr...add more cr and theyll easily push 200 w/ tunning of course...stg 2's get a hole lot more top end but lack bottom end..so do expect that holeshot off the line, expect to tear it up on the top end like most honda's do....other recomendations are zex cams....they put a ton of time into their smaller lobe research so unlike other cams youll get power over 85% of you powerband...and for most people doing autocross etc this is what they desire...for drag you want the high lift long duration cams that scream at 9grand...neways sorry bout all the blurb but hope you learn something....and dont forget its how you parts work together...say it with me "harmony" ...for example a header that gives low end torque aka 4-2-1 setup will shift you powerband left, and if you try to run a cam that wants power in the upper rpms, you parts fight eachother and sometimes cause worse performance...that why you must plan out you goals and powerband locations...and base you parts off of that! huh that was a lot of typing

 

the main advantage of the vtec killers is the fact that they remove the LMA's and take away alot of weight from the valve train, allowing even more revs.... and the only way to make more power is to rev it higher

 

WTF are "vtec killer cams"?

 

Might I ask what LMA's are?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jsxtek &raquo;</TD></TR><TR><TD CLASS="quote">Might I ask what LMA's are?</TD></TR></TABLE>

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Quick 200k Mile Motor &raquo;</TD></TR><TR><TD CLASS="quote">.

yup, the LMA's keep the center rockers in control. The center rocker doesn't have any valve spring underneath it to keep it against the camshaft.

LMA's are cylinders with springs inside them. They keep the valvetrain quiet when not in VTEC. Without them, the VTEC center rocker arms would tick up and down.

You dont want too much motion. The pins inside the rockers must be aligned in order for vtec to engage.

Do a valve adjustment according to spec, and if you still hear the ticking...
it might be the LMA's </TD></TR></TABLE>

hope that helps.

 

LMA = Lost Motion Assembly

 

lma's put resistance on the middle of the rocker arm when vtec is not engaged.....think of it like this ( )= outer rocker arms.....^= middle rocker arm...when vtec is not engages it is running just the 2 outer ( ) rocker arms on the secondary cam profile...when vtec engages it pushes a pin between all three rocker arms (^) in essence running the three connect will run on the primary lobe....what the lma's do is keep the primary lobes rocker arm ^ from flaaping around in between the two secondary lobes rocker arms...if it didnt it wouldnt be ablew to slide the pin over so easily when engaging vtec....and for the kid who asked what vtec killer cams do...open you eyes and read!...and btw lma's dont reduce valvetrain weight....the reduce valvetrain resistance! creating easier revs or motion that requires less work

 

Haha thanks.. Took be a bit to read all of that and actually get most of it but I think I got it down.

 

sweetness...someone actaully taking my mombo jumbo and understanding

 

more info...i love it keep posting and ill keep reading
you guys and girls are the best

 

Those cams are CRAZY!!!!!

Does anyone have them on their motor???

 

http://www.todaracing.com/prod....html

I say why do you need them. $1800 for the cams, rockers and shafts and another $360 for TODA valvesprings and then you would need cam gears also... for this money you can retain VTEC and do alot with it. These cams are for dedicated
drag motors and will idle like a limp camel. Would make street driving a pain
in the *** not to mention can your stock block withstand constant use between 5-9500+rpm? What about piston to valve clearance on stock piston valve grooves? Or an exhaust that can work efficiently at those RPMs...?
How about the ECU? hmm, injectors... sounds like something for teams with sponsors and professionals to use Get yourselfs some R or stage 1-2 VTEC
cams, raise compression have the car tuned and be happy with that. 35 extra
whp on a GSR or ITR is alot of Fn power. There are no shortcuts either if you want
your motor to last on the street and drive/beat up daily.


Modified by MikeSarr_GSR at 5:54 PM 5/16/2003

 

how good link to that soundclip

 

Then why not just run ferrea's roller rocker set up?
Schu

 

We have beat this subject to death!

If you aren't drag racing, road racing, or have a race car, you dont need VTEC Killer Cams.

Some people run them on the street, but they have ***** the size of watermellons, and spend tons onf money on their engine.

The guy who is in the vid, he posted a reply. Aparently his car is semi-streetable. He said he takes it to lunch like once a week or so. Hell that good enough to me.

I'm convinced, with the Toda Sport injection kit, SERIOUS ECU tuning, and a fully built motor, you can run these bad boys on the street. And LOVE every bit of it.

So to all the guys who run them. Street or not. These are some serious ******* cams.

 

but doesnt it seem like a waste of having a vtec motor if you are not even using it? If these killer cams are such a good idea, why aren't more people just building up LS motors? Same thing. just a better balanced rotating assemble, and slightly better flowing head.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by B16B &raquo;</TD></TR><TR><TD CLASS="quote">but doesnt it seem like a waste of having a vtec motor if you are not even using it? If these killer cams are such a good idea, why aren't more people just building up LS motors? Same thing. just a better balanced rotating assemble, and slightly better flowing head.</TD></TR></TABLE>

One problem you're over looking: LS motors can't rev to 9500rpm safely while B16A and B18C's can due to their better rod/stroke ratio.

TODA Vtec Killers are for dedicated road race motors. If you're not sure you need VTEC Killers, you shouldn't get them. They're for highly technical users.

 

Plus the LS head is not the best flowing head Honda let out on the market. Even if you p&p it then itr head p&p will still out flow it

 

my quote:

"just a better balanced rotating assemble, and slightly better flowing head"

--------------------------------------------------

Blade :

LS motors can't rev to 9500rpm safely while B16A and B18C's can due to their better rod/stroke ratio

_----------------------------

I know that, but it is very possible to "balance" an LS bottom end, and use ARP rod bolts. That should take care of the tipical unreliable bottom end reving past 7500 rpms.

That with a ported out head and some big *** crower cams would most definitely make some huge honking power. Coupled with ITBs and some serious tuning, it would be very very fast.

I am surprised people dont use webber DCOE's anymore. They make serious power, but are a bit tricky to tune for daily driving.

 

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

One problem you're over looking: LS motors can't rev to 9500rpm safely while B16A and B18C's can due to their better rod/stroke ratio.</TD></TR></TABLE>
If this is true, then why do so many people run LS/VTEC engines and rev the hell out of them? And I'm pretty sure that if someone is shooting for the kind of output that vteckiller cams produce, they wouldn't be using stock LS internals. To me it just makes more sense to build the hell out of an LS, than to take the VTEC out of a VTEC motor.. building the LS would be a whole lot more economical. That's my $.02 though.

 

reason why people run ls/vtec is for torque...nto high revs! Yes it is possible to rev a ls/vtec to 9000+ but it wont last all to long unless its built correctly...a b18c1 or b16...can rev to 9000ish w/ just upgarded valvtrain where as you best have shotpeened rods or af rods in the ls/vtec because they're gonna snap if you dont! and about block girdles the gsr has reinforcement on the crank..where th ls doesnt many debate over if it helps or not, plain and simple it helps, but is it neccesary...not really