bdawg/98mechamta#9

Ok guys after this post im done asking questions . Is the mti "R1" (232 / 236 , .57x" ) vs. a comp XER with the xer lift 232/236 probably .60x" a big HP difference ? Basically how much HP is in the extra .03x" lift , assuming that my heads flow real good ( 300+ @ .6" ) ?
both on a 112 + 4
thanks guys and your answers will make my decision !!

bdawg/98mechamta#9

TTT

Cal

iTrader: (1)

I don't think HP difference would be very big, but that 0.600 lift would be bad for springs. I'd go with the 0.570 lift just for that reason.

bdawg/98mechamta#9

thanx cal , i would go to big dual springs if needed.

this does bring up the question of hp increases with more lift . i think its a good question

anyone else ?

DONAIMIAN

iTrader: (18)

Your heads will never flow to theyre maximum potentian while on the car, so I wouldnt bother going antything over .580 unless you had some monster solid roller set up, that was race only.

verbs

Look at the GX2 cam...big lift, big duration, and making a buttload of power.

If your heads don't flow well you won't utilize that big lift.

As far as running big lift, get yourself double springs, titanium retainers, and some Yella Terras to reduce friction and weight on your springs. The YT's should help prolong spring life a bit...but with that much lift you'll be changing your springs every so often.

NX†C

the difference between the 2 types of lobes would really be the determinant for spring type. If running the R1 with the XE lobes you will only see the 0.575 I/ 0.578 E versus having XER lobes and then seeing lift of 0.595 I/ 0.602 E and be pushing a touch over the limits of the Comp 918 Blue Stripe spring. In this case then you would want to opt for a dual spring but it all depends on what you want out a valvetrain. Personally I wanted a fast intake and therefore got a reverse split with XER lobes on the intake and XE lobes on the exhaust. I feel that the LS1 has a really good exhaust stroke and didnt need the additional ramp rate of the XER potential as the intake is not as efficient and inversely could use it. Hope this helps or makes it a little easier to decide the path best for you.

Cal

iTrader: (1)

I've heard this analogy: When you first open a water facet, you get a lot of flow increase for each increase in valve opening. But as the facet gets closer to the wide open point, each increase gives diminishing returns in flow.

So I guess it depends on what your goal is; if you are a hard core racer, every little bit counts; otherwise, you hit a point where a lot more money, maintenance, and complexity is only neting a little more performance.