Quote Originally Posted by TheChosenOne
Listen...

Ls/vtec aren't for the weak hearted. They DO make more power than a Gsr; stock for stock. But just like previously stated, if you don't built it right, it's more than likely going to last as long as a disposable contact.

Now, they are both l.8 liter motors with identicle Vtec heads (depending on whether you use a gsr head or a b16 head), so obviously the difference is in the block. THe pistons are the same size, but the stock gsr pistons will yeild a higher compression ratio.

The crank in the LS is the key to making power in an Ls/Vtec. It allows for much more responsive low end torque (even more torque with a b20 bottom end) than a Gsr.

Theoreticaly, ls/vtec's are not ment to be reved past 8k rpms, while gsr can go past 8k with no problem.

The question is whether you want power or reliability.
you can make just as much power with a GSR as you can with a LS/VTEC... The reason the LS/VTEC makes more low end torque is because of the slightly longer stroke (heavier crank=more rotating mass=more torque), which is also what makes the LS/VTEC not capable of the higher RPM's that the GSR can handle. Stock for stock, a LS/VTEC will make about the same hp as a GSR. The reason most LS/VTEC's make more is because a lot of times people will go ahead and get a set of pr3 pistons or p73 pistons to raise the C/R. Also, chances are that most people are going to run a chipped ecu and have the car professionally tuned (if they are serious about how their setup runs). A good tune is what makes the difference between a stock GSR engine and a LS/VTEC.

Bottom line: LS/VTEC's make good low end power, but are not as reliable as the GSR, and (unless built) can not handle the higher rpm's necessary to make the most power with the VTEC head.

In the end, a GSR engine is more reliable, and as soon as you start building, both are just as capable as each other.