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MO on LS/Vtec

11-10-2005, 10:10 PM
Now before i start, im not creating this to piss anybody off, more just to voice my oppinion on the LS/Vtec setup.

The LS/Vtec setup has become a common and more common setup over the years. For those of you who dont know what an LS/Vtec setup is, its taking the block from a b18a/b and mating it with any of the DOHC Vtec B-series heads (b18c5, c1, b16a, b17a, so in turn getting lots of torque from the b18a/b's longer stroke, and getting the top end from the high revving vtec system, while a very potent system this is, it also has many downfalls that can lead to serious problems.

One problem is the R/S ratio. R/S ratio is the the length of the connecting rod to the length of stroke. With an LS/Vtec setup the R/S ratio is dangeroulsy low which means that its pushing against the cylinder walls many times harder (due to the horizontal angle the piston is pushed up at, due to low R/S) then what its meant to. This in turn can cause engine internals to wear quickly due to the high stress, it also causes great stress on rods as well (Due to low R/S). And eventually can change the round, cylindrical shape, into an oval, leading to leaks, compression drops, and so on.

Another downfall is how high an LS/Vtec can be safely revved, from what ive been told LS/Vtecs normally dont rev much over stock redline rpms, ive heard that on a built bottom end the highest you can push the redline is somewhere around @ 7,500 and thats with a built motor, even at this level the vtec system is not operating at full potential.

Most people use this setup in order to get good top end, and good torque, which it does achieve to a certain extent, but our hondas make power through revving high, and utilizing the vtec system, not low end torque, trying to pull torque out of a honda, IMO, is a waste of time. Were driving 1.6-8 Liter 4 bangers, not 5 liter 454ci v-8s.

IMO the LS/Vtec is only worth it if you have the money to keep replacing bound to wear parts, Im not shunning the LS/Vtec, all in all it is 1 hell of a motor, but at a cost.

Thanks for reading :rofl:

11-10-2005, 10:59 PM

not one worthwhile fact just 2nd hand BS.

my bottom end is ready for 9K.

I really am kinda tired and buzzed but trust me your wonrg.

11-12-2005, 04:59 PM
that was kind of a useless post and if Ace is right, which he probably is, then there was no use for your post at all.....

11-13-2005, 03:01 PM
yea thats right LS/vtec is just as reliable as anything else if you build it right...thats IF you build it right...

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