i have read numerouse places that i need to buy or get a set of pistons from a vtec motor because the ls pistons do not have enought valve relif for vtec i know that b16 and b18 pistons are the same bore so do i need them??? i dont want to spend $500 on new pistons if i dont need them any info is greatly apperciated thanks

 

Wrong forum, try posting in all motor, not forced induction

 

That is not true. You will be fine with ls pistons.

 

He did not state it (which he should have), but he may be going ls/v-t.

 

you make a very good point grasshoppa! are you doing LS-Vtec Turbo???

 

yea

 

i just assumed you guys would know thats why its in this fourm

 

its always a good idea to post it up anyways. as far as your question, im not sure about clearance between ls and b16 if any, but why not go ahead and replace them? its always a good idea if you already have the motor apart to go ahead and replace stuff... better now than being 2x more expensive later on when it has to have it done. just my .02, just a good idea and extra peace of mind

 

well if a gsr is 10 somthing comp and ive built turboed gsr with stock pistons and they have the clearence to boost i dont see how 9:0 or 9:4 comp ratio cant boost?

 

On the stock LS/V setup, you'll be fine to boost. Many people push their stock engines into the low 300s and daily drive them. Just do your research, build a good setup and be sure to get a good tune. Those are the keys to making your LS/V last

 

the ls pistons do not have a big enough valve relief for the vtec valves, so when you run aftermarket cams you have to watch out, although on stock cams you should be fine

 

X2!!!!!

You can also check your piston to valve clearance before you actually run the car. I did an LS/V swap with a B18C head with ITR cams. Also can always go with a thicker head gasket.

 

what size throttle body should or do i have to run

 

For the stock engine that can withstand about 300whp or so, stock is fine. You're not scavaging air like in an NA application, it is being FORCED (hence the name of the forum).

 

im going to have like 380whp so does that change anything

 

Another point, dont get too happy revving to 8.2k+rpm at every stop light with the weaker LS rod bolts...

I say drop the money on a new set of pistons and rods now for both extra insurance and also ability to go up in the hp later.

 

exactly what he said... if you run stock rods and pistons you are limited to the power you can make and how safely you can rev the engine past 7500.. while the motor is out of the car and apart, it is much easier and probably cheaper(since you take the risk of messing up the block, or bending a valve or trashing the head completely if you stretch the rod bolts or snap a rod) you should just get some eagle rods and je pistons (or w/e you perfer) and put them in, that way you know the motor is fresh with new bearings and rings and if you get a good tune you shouldnt have any problems ... my .02 hope it helps