does turbo go well with vtec ive heard that when vtec kcks in with turbo its not good like they dont run right together someone please explain simply.

 

i dont want to cause any problems but, vtec is not really the best for turbo, vtec has such high overlap for the filling of the cylinders at high rpm that you tend to lose the boost, it just flows right back out, not all of it but some of it....thats why you can call crower and get what the call vtec killer cams....where the vtec lob is ground away, these are full race cams because the car will run like poop.....

but dont get me wrong vtec is fantastic.....just not perfect for boost....

my vote would be for non-vtec, SOHC and DOHC.....

 

vtec works fine for boost and will always make more power than non vtec

 

that is not true. whoever told u that is an idiot.

 

this is not true. THere is no overlap w/ stock cams a good set of cam gears cant eliminate.


[Modified by DIRep972, 7:19 PM 5/15/2002]

 

no one told me that i saw it, and everyone else in the import industry will say the same....

yes came gear can dial out the overlap....and if you are saying that cam gears can dial out the over lap you are admitting that there is overlap which is proving my point

 

these are all personal opinions.....that was what the vote was for right

 

Stock overlap is NOT a problem
You take 2 stock motors, even out the CR, and the vtec motor will always make
more power at the same boost level.

 

I am with Steve on this one, VTEC motors with turbo make more HP.

 

Are you asking because you are trying to decide which motor to build? That's my current situation and I decided upon the b18b for cost. I also am not wanting to build a 500hp monster. I can't tell you whether or not VTec will help you enough to warrant going with a vtec motor. It just depends on what you are wanting to build.

my 2 cents

Noel

 

First off, vtec are very good engines. I just wanted to get that out of the way so everyone does not think i am flaming them. Now for technical jargon, it is known that vtec hinders performance of forced induction due to the overlap in the cam profile. In the higher rpm area (such as for vtec) the cam profile has too much overlap; long overlap is necessary for naturally aspirated engines, but say with 15psi+ of boost it will hinder performance. as far as vtec out-performing the non-vtec engines with the same set up, well yes that is both false and true. a very good example of ACTUAL NUMBERS and DYNO can be seen in the super street with the megaire's type r that is turbo and supercharged. you can see on the dyno plot where vtec engages and the horsepower actually drops. on some of the big daddy race honda's, the guys actually grind off the vtec lobes of the camshafts. anyways, its a toss up on this issue in my opinion. once again, im simply stating some theories, facts, and other info.

 

thank you i got worried because so many people were telling me i was wrong, i thought i was going crazy

 

It's possible there are exceptions (improper tuning?) but, I've seen dynos with vtec turned on and off on turbo cars and there is DRASTICALLY more power with VTEC...less than 300(without VTEC) vs. 400(with VTEC)...This was at about 15psi... Maybe the physics change if you're running 30+psi, but if you're actually driving it on the street...VTEC will most likely be better. Besides, if you start making that much power, just turn it off and see what happens!

 

ahahah

 

to me it seems pretty simple... car with more power to start with and has equally good tuning as the car with less power will always have more power.

 

ok, asides from the actual cam...the head is much better on the vtec motor. The ports can go bigger and if nothing else, the whole valve train is just made better. There are companies that can take out the over lap in the cams anyways...Mike

 

wow.. there sure is a lot of mis-information out there! I was told that VTEC is automatically disabled whenever you turbo a VTEC equipped engine. I guess it is true since I haven't heard my VTEC engage since I added the boost beast.

Now if you believe that load of crap I have some beachfront property in North Dakota that I woould LOVE to sell to you!

 

No Dee, its ocean front property in Arizona. If you buy that I'll throw in the golden gate in free.

art

 

Can I just buy the golden gate? I think I might pull my cams and grind the vtec lobe off. I think there might be lost power to be made by doing this.

 

Correct me if i'm wrong about this, but, the reasons a VTEC head is better is:

1.) Better flowing head and manifold...
2.) Larger intake valves..
3.) More lift and duration, which equals more air/fuel may enter chamber...
4.) Better low RPM and out of boost engine response and mileage...
5.) Better chamber design...

Now, theoretically, if a non-VEC head were ported and had oversize valeves, different manifold, throttlebody, etc...i could reach or even exceeed the HP levels of a VTEC head, but at the sacrifice of low/mid RPM HP and mileage (like riding a big cam all the time)

IMO, the VTEC head was desgned BY HONDA, to make more power than non-VTEC, and HOnda knows what they are doing...so stick with the one that makes the most power stock..buy some cam gears, dial out that overlap (lose some duration too, but ohh well), and be done with it...

 

well why do people grind the lobe off when they can just disable the vtec?

is this not possible?

 

Disabling VTEC will not make power becuase u are losing the big cam profile...which produces the extra lift and duration that you would normally want....although too big a cam profile will lose power, but the stock cams are ok...if u were running some JUN cams in a turbo VTEC car or sumthin, that would lose power...

 

Heres wrong with the ls head....You can NOT port it as big as a vtec head.....And the valve train sucks, way more prone to break.

 

A moderate amount of overlap is good on ANY engine.

Just due to the virtue of the extra ~1000 RPM to play with, the VTEC motor will do more work(make more HP).

Of course, a little bit of boost definitely wakes up a B18B1, and you can still make lots of power without 3rd gEaR V3tC y0!

 

Tell me if i understand the correctly... If i just disable my vtec it will just lose power and do nothing with the overlap... but if i keep vtec and use cam gears to advance/retard the overlap i will make power or not lose as much power.