with the money you spend on doing the lsvtec conversion, you could aggresively build your current LS motor to be just as fast, if not faster. I say don't waste your money.

 

The two most common problems are bending/breaking rods, spinning rod bearings and leaking oil.

Problem: Common cause: Common fix

Bending/breaking rods: Overreving on stock internals: Shotpeen or replace rods with aftermarket units.
Spun rod bearing: Overreving on stock internals: Adapt B18C block girdle or add Z10 Engineering block girdle or similar.
Leaking oil: Improper VTEC oil feed port sealing: Reseal the VTEC oil supply port with a 1/8 NPT plug or welding.

If it is built right, it is every bit as stable as a B18C with a few CC's more displacement. If you still don't trust it, throw in a B18C crank and rods. That will take the R/S ratio from 1.54 to 1.58.

 

I was told that Ls/Vtec can put out higher # over Gsr's.

But I was also told that Ls/Vtec motors will last only about 20,000 miles after being converted.

So it has its up's and downs.

Anyone know anything about B20/Vtec and its reliability?

 

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?

 

the r/s ratio has to do with the bottom end of a motor, the head doesnt have anything to do with the r/s ratio.

 

So it relies on the crank since all of the B18 blocks are pretty much the same size?

 

Yes. Rod/Stroke ratio is the ratio of the center-to-center length of the rods to the overall length of the stroke.

B16A and B17A blocks can swap crank/rod combos.
B16B and B18* blocks can swap crank/rod combos.

You can't swap between B16A pattern and B18* pattern blocks because the B18*'s deck is about 9mm taller.

 

Good to know. Thanks

 

they can when built correctly. the thing about them lasting a certain amount of time is dependent on how well you build it. the realiability of a b20vtec would be the same as an lsvtec.

 

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.
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