Scantron

I heard the other day that putting a Turbo on a v-tec engine doesn't go right, its better to turbo a non-v-tec engine correct? Sounds like turbos don't like v-tec engines... What do you guys think???

HAPPY

Well -- in full race applications this may be true. vtec cams do generally have a bit of overlap that is not ideal for turbo...but for street use...to say vtec and turbo does not go is just plain wrong.

bbarbulo

iTrader: (2)

turbo and vtec are two technoloies that compete in the same area of the power band - high RPM.

tubros generally make boost when they spool around 3000, and VTEC really only works 5000+

so turbo does NOT benefit from VTEC, and VTEC does not benefit from turbo, in fact VTEC hurts turbo with the extended overlap to help exhaust scavenging effect.

and VTEC motors have higher compression than non-VTEC honda engine, so... they are safer under higher boost levels.

the advantage of a VTEC motor, however, is the great flowing intake manifolds and heads... so if you just turn off VTEC, put some non-VTEC pistons in it, you'd make more power than a similar all non-VTEC motor.

spracingsports

hey Bruno, did you get this backwards??? i thought low compression was the safe one?

HAPPY

Yeah - that's kinda what he meant. Truthfully, higher compression motors will always make more power...but the problem is that they are harder to tune safely...so most guys will stay with a 8.5:1 to 9.5:1 ratio for boosted applications.

zeeman

iTrader: (1)

my best friend has a built b16 turbo crx and as soon as he hits 5200 rmps (vtec) his boost instantly jumps 3-4 psi. I don't see what's wrong with that.

Gunmetalef

you dun even notice it under large amounts of boost... in my buddy's ITR you dun hear or notice it

Chigga1

are u serious??????

your telling me his boost spikes up 4psi???
not good for the pistons.... they'll melt sooner or later....

whenever a turbo spikes in boost, something must be wrong with the manifold.... i heard those DRAG manifolds suck,,, and are notorious for boost spikes

imported_chillinit

I don't think so bar....

zeeman

iTrader: (1)

he doesn't need to worry about melting his pistons in his "fully built" b16 turbo crx. I guess i wasn't too specific when i said built. The only thing stock is the cams and crank. Everything else was built for boost.
I don't see how his boost raising 4psi is bad. While "in" vtec the air flow changes or improves, now correct me if i am wrong, but if the airflow in and out of the engine is increased would the turbo not create more boost?

white92d15b7

OHHHHHHH someone is going agianst the great BBarbulo !!!!!!!!!! does barbulo's knowledge end here !!!!!!!!does barbulo have a turbo car!!!!!! hmmmmmm the saga continues !!!!!!!

personally from seeing what a vtec car does turboed vs a non vtec turboed car does on a dyno there is really no difference cuz the turbo jams 10 Psi or whatever in there whether the vales are open 1 mm or 10 mmm

Nova_Dust

Initial D has a Turbo ITR, is kicks ***! But still lost to the FD :P

Boojamin

There is nothing wrong with running 7 - 8 pounds of boost on any vtec motor, aslong as you watch your oil levels, you should get a pretty reliable beast. Aspecially the d series vtec, the compression is 9.2:1, it is true the lower the better for safety, but higher compression with a turbo produces more power, with less saftey. A b16 or b18 are higher compression as we know, and they will take 8 pounds no problem. there is no need to turn off vtec by the way, or change the compression. Just slap your kit on, and tune it, and it is fine. I have run turbos on vtec motors for a number of years now, and well, I have only had one problem, and it was my own fault, oh yea, make sure you are rich !! and thats not in the pocket, that is ment in fuel.

gavinjay

turbo + vtec do not mix.....
well they do, but its dangerous

vtec motors are fairly high compression....usually over 10:1

for a turbo car that u wanna boost the **** out of u prolly want to be running like 8:1 or so

someone said sumfin bout turning off vtec.......well........why not just boost a sohc motor? esentially a doct with vtec off is a sohc with an extra rod jsut sitting there

plus your dohc engine revs to like 8k becuase from 5 or 6 or w/e ur vtec is at it uses those cams....you dont want those stock cams reving that high

but basically turbocharging a high comp motor would make u some good power.......but ur pistons wont last very long

Boojamin

Is this information from experience ? I think not, really you are simply wrong and D series it not 8:1 and what is this crap about :

"esentially a doct with vtec off is a sohc with an extra rod jsut sitting there "

Were do you get that from, that is a crock. Its simple, Hundreds, thousands of honda finatics turbo there Vtec motors,where do you get your info from, you state theory, but in theory you should know what you are saying before you say it !! and I have a vetc turbo and have for many years as well as my friends, and maybe spend some time with a tuner and get your sh-t together !!

imported_b16turbohatch

i agree with boojamin because i have a turbo'd b16 at 9lbs of boost with stock internals and have no problems. Using v-tec is all in the tuning and the overlap v-tec causes can be tuned out and used to make more power then a non v-tec motor would so like Boojamin i know my s**t and i know from experience that v-tec and turbo's do and can go together very well.

gavinjay

i didnt mean its literally got a camshaft in there doing nothing....
but each of those cams have the extra vtec lobes on them doing nothing if vtec is off....
and then u got that vtec solenoid sitting there doing nothing

i dont remeber saying sohc's are 8:1 compression but i said thats a good compression to have when ur playing with a lot of boost

n e way, i do have experience in this area....and a close friend of mine turbo'd his 91 hatch with a gen1 b16....
and shortly after fried one of the pistons

plus i never said turbo + vtec wont work i just said its better to go turbo with a non vtec motor

then again, like b16turbohatch said.....if its tuned properly then ya thats fine and u can make a lot of power that way too

Boojamin

b16turbohatch gots the hands on experience, and that is needed to have an educated opinon on the matter.

It is plain garbage to say a non vtec is better than a vtec with a turbo. The technology is better than not having it to begin with, it is just as effective, if not more when a turbo is combined with it. As far as your buddy who melted his piston, well that is one situation, and there can be many reasons for it, to assume that your 1 friends situation represents all turbo vtec situations is plain stupidity. And having a friend with the setup is not having experience, building one and racing one for years is experience.

My neighbour is a doctor, guess that means I have all the experience I need to open a clinic ................... puff puff

imported_b16turbohatch

LoL boojamin thats is funny but listen, tuning is everything and it also depends on your set-up ie. internal or external wastegates and so on. some people just build homemade kits with vafc hacks and they are just not that tuneable and some of us spend lots of money and get racing shops to build turbo kits for us and use such things as piggyback systems and full stand alone systems for tuning. that is the way to go spend the money on a good turbo kit and engine management system and you can make some crazy numbers on stock internals like i did lol.

Boojamin

you know, you know it brotha