if you do lsvtec, with a b16 head, will you keep the same low end power as with the ls? how are the si lo cam profiles compared to ls cams? i'm trying to decide whether to go lsvtec, or go all motor ls. ls vtec i won't have to pull my motor, but if i go all motor, i have a set of ctrs i want to use. so if the low end is the same or better with a b16 head, that looks like good plan.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SlickCRX &raquo;</TD></TR><TR><TD CLASS="quote">if you do lsvtec, with a b16 head, will you keep the same low end power as with the ls? how are the si lo cam profiles compared to ls cams? i'm trying to decide whether to go lsvtec, or go all motor ls. ls vtec i won't have to pull my motor, but if i go all motor, i have a set of ctrs i want to use. so if the low end is the same or better with a b16 head, that looks like good plan.</TD></TR></TABLE>

When it comes to production of low end torque, the low RPM lobes on a VTEC can are king. That is what they were designed for. And since decent top end power was not part of the design requirements, there was no need to compromise to keep top end power usable. By contrast, an LS cam is more of a compromise since a single set of lobes must work pretty well over a wider RPM range. For this reason, an LS cam is geared more toward the production of midrange power than the low RPM lobes of a VTEC cam. And this is exactly what you see in a dyno comparison of an LS-VTEC vs a straight LS: better low end and top end with the LS-VTEC and better midrange with the straight LS. Keep in mind that the differences between the two in the low end and midrange are small compared to the differences in the top end. In other words, by going LS-VTEC, you gain a little low end torque, lose a little midrange, and gain ALOT of top end power.

 

good point, thanks.

 

When it comes to production of low end torque, the low RPM lobes on a VTEC can are king. That is what they were designed for. And since decent top end power was not part of the design requirements, there was no need to compromise to keep top end power usable.

I have never heard this before in my life...since when did VTEC become the king of low end torque? I(owning a LS crx) know that there is NO WAY IN HELL any vtec engine has more low end than me. I see what youre saying about them having no affect on high end because youve got the vtec lobe...but those "powerful" low end lobes are meant for high gas mileage so they make no power. And from what ive heard...the only reason you gain any low end torque with an LSVTEC setup is the fact that the VTEC heads flow WAY better than the LS'. But i could be wrong here...storminmatt is a smart guy...lol.

Back to your question...i personally would go with the all motor LS, cuz either way, if you do it right youll have to tear the block apart. I say get some headwork and beefy cams, skunk 2 IM, big intake to supply alot of air to those cams, a nice set of headers, adjustable fpr, and an afc. Tune it all and run 13's all day and be very happy and reliable.

Sean




Modified by sCeRaXn at 8:14 AM 7/9/2003