So I don’t really want to build an LS Vtec, but just to get a better understanding of how/why, and try to figure out if it’s possible to build a GSR motor basically out of an LS block, and a B16 head. Please read on. I’ve done some research but still have questions.
OK, so I beleive what most people do with an LS Vtec is to use the entire LS bottom end, crank, rods, and pistons, and then slap the vtec head on it with the extra oil lines.
What I’ve also heard is that what makes the power/causes the problems is an odd rod/stroke ratio. Basically that the LS motor strokes further than the GSR or B16 motors do? and that the fix is to balance the crank and sometimes use stronger rods/rod bolts. I beleive this is because the odd length of stroke puts sideways pressure on the whole setup and at the high RPM’s needed for vtec, this causes extra stress that a GSR/B16 motor are not under, and can cause the motor to come unglued unless strengthened.
So what I’m wondering, is can an LS block be combined with a B16 crank to creat a Vtec engine (as opposed to an LS-Vtec engine), to my thinking it would creat a GSR engine? Will doing this eliminate the side stress on the bottom end? if so, what would one use in the way of pistons/rods to create a workable setup?
Theory’s are nice, but actual experience is priceless. Thanks, Ben Inglis
well then what’s the point of going through the trouble to do an LS/VTEC? you would basically have an SIR or GSR with the price of getting the VTEC conversion kit, and have crappy compression, so would be even slower…not worth it at all.
No. The whole feature of vtec is actuated by the oil pressure and cams. On the standard LS cams is two lobes, one for intake valves, one for exhaust valves.
On a Vtec engine, the cams have a third lobe. This lobe is free floating up to 5400 rpm (or lower if you lower the vtec engagement). It is at 5400rpm that there is enough oil pressure, actuating a pin that locks the third lobe. The third lobe is larger, causing the intake and exhaust valves to open wider and longer, producing more power at higher rpms…
Simply putting a micropolished and balanced crankshaft would allow you to rev higher, but that would cause more stress on any non reinforced parts…
SCC did a GREAT writeup on Ls/Vtec…Go to their site and check it out…
right, i know about the vtec cam thing, perhaps I should give a little more info on my plans/setup.
I currently have a B16 in my hatchback, turbo charged with a super mild “build” on the motor, just new rings and lower compression pistons. It runs great but smokes a little and my wish is to build a stronger motor, to handle more boost etc. I have an LS motor I pulled out of my brother-in-laws car when we did a B16 swap in it. So I was hoping, that it would be possible to have that block sleaved, and all the machineing/hard work done to it, allowing me to do final assymbly myself with the correct parts. Allowing for a shorter amount of down time as I have a local shop I would trust with the crank balancing.
The end goal not being to have a turboed LS-vtec (wich I think would be over kill, and prematurely end the life of my motor) but to have a bored out GSR (or b16) motor to turbo charge.
i have an lsvtec and mine runs, and it runs pretty damn strong. This is what you need for a reliable ls/vtec, use stock head and valvetrain unless you got alot of money to build your motor i didnt, gett the rotating assembly balanced, type r pistons, arp rod bolts, and head studs, i have a block guard, type r oil pump & water pump timing belt pulley and spring, get a new fly wheel and clutch while you got out the motor, get the golden eagle conversion kit it will make life for much easier, run the b16 intake if your gonna have stock cams, bu ti think thats about it for the motor, but i dunno i know im fortgetten shit but that good start for you.
Thanks for the info, the type r oil pump/water pump/timing belt stuff is especially helpfull. other stuff like the arp bolts i knew and was planning on. Thanks, Ben
LS vtec turbos arent over kill they are money.
Fully Built, AEBS sleeves, forged internals
360whp @15psi
Nosintegra92(allan) is going for20+ lbs and will dyno that soon.
i havnt run mine bet im guessing when i get it tuned in and some slicks maybe 13.9’s or low 14’s, i still got the ls tranny though, but hondah22, your car has gotta be hitting 12’s, i wish i would have gone turbo now
read my freakin posts, i’m not doing an LsVtec, i want something different