Originally posted by jinx-mitchell
Ah. Got it. Is it the same head with lower compression? Or are the pistons and cams the same with diff head?
Originally posted by txhatch
Same head but the jdm 98 specs have different cams.
The JDM ITR gets its higher CR from different pistons. The '98-up JDM ITR has 3 degrees more duration on the intake cam, that's all---the same cams as the CTR. The '98-up also gets a header with a 2.5" collector instead of 2.25" and a 2.5" exhaust to go with it.
Originally posted by jinx-mitchell
I've read that the LS rods are okay to run if everything else is done correctly, but maybe I'll get some GSR or ITR rods anyway. I was going to get a GSR crank anyway. So provided that I do the job correctly it looks like most people think I should just go for the LS/VTEC...
The heads I'm looking at are:
B18C5
B18C1
B16A
What do you guys think? I was told that the B16A will give a great R/S ratio at 1.74. Is this true if the only part I use from the B16A is the head?
You don't need to change the crank. Destroking the motor is unnecessary. The thing you should worry about he MOST is the rods over everything else. You can be fine with some shot peened new stock rods (i.e. buy em from the dealer and send em off to be shot peened) and ARP rod bolts.
R/S ratio has nothing to do with what head you run. It's the the ratio of the length of the rod to the stroke, hence the name. Which head you use does affect the compression ratio though. A B16 or ITR head will give you 9.5:1, a B18C1 will give you 9.7:1 CR. You can use either head just fine, B16 is the simplest and cheapest to get a hold of. If you want to run a higher CR then plain ole USDM B16 pistons in the LS block with B16/ITR head will give you 11.5:1 which is about as high as you want to go.
The key here is getting the ECU tuned properly to run the motor. That means getting your hands on a VTEC ECU and having it converted by Hondata or getting a VTEC ECU and VAFC to tune it. Having it dialed in on a dyno will improve the overall project vastly.
So here's a pretty basic LS/VTEC parts list that'll put out good power and not blow up:
B16 head
B16 pistons
new B18B rods, shot peened
new rod bearings
new main bearings
new thrust washers
oil return line for VTEC system
VTEC ECU
Hondata or VAFC
DYNO TUNING