ls vtec build question

[JoshuaH]

I built an ls vtec on the last build i used the p30 pistons and it ran bad ass. A guy from Dallas, Tx has an ls vtec with ITR pistons i know its possible with machine work but what would some of the consequences or complications would i might have with that type of setup and what exact type of machine work do i need to get this done.

 

[ef9hatchman]

I built an ls vtec on the last build i used the p30 pistons and it ran bad ass. A guy from Dallas, Tx has an ls vtec with ITR pistons i know its possible with machine work but what would some of the consequences or complications would i might have with that type of setup and what exact type of machine work do i need to get this done.

make sure ur sleeves meet the specs for the itr peeeestons. like boring Stock bore on all B series is 81 although when driving the pistons move up and down at the top of the sleeves you will have warpen. so hone it and get like 81.5 pistons if you bore it to that. ok. dont mickeymouse it Take it to a shop to do it if u just take block bare itll be easier on you because they will be like ooo i needed to tak block apart that this much yaddah bs you know.

 

[LS_VTEC]

ITR pistons in an ls block will give you lower compression than it would with p30's. If you want big compression that CAN be done on pump gas, go with ctr's. The rod's have to be cut to fit the ctr's and you might as well spend an extra 60 bucks on ARP rod bolts just for "cheap insurance" purposes. As far as the block goes for machining, just keep it stock bore you will be fine. The stock bore is 81mm. Have a shop hot tank the block and hone it. They will look for other things (if needed), like a ridge ream, line bore... etc. But if the block is in good condition, a clean-up and fresh hone is all that will be needed. From there, order your pistons in 81mm form. NOT 81.5mm. Its also a good idea to have the rods shot-peened to make them stronger. As far as the rest, just replace the main and rod bearings, new rear main seal, new oil pump and water pump, both from a 96+ gsr so you can use the gsr timing belt.

 

[ef9hatchman]

ITR pistons in an ls block will give you lower compression than it would with p30's. If you want big compression that CAN be done on pump gas, go with ctr's. The rod's have to be cut to fit the ctr's and you might as well spend an extra 60 bucks on ARP rod bolts just for "cheap insurance" purposes. As far as the block goes for machining, just keep it stock bore you will be fine. The stock bore is 81mm. Have a shop hot tank the block and hone it. They will look for other things (if needed), like a ridge ream, line bore... etc. But if the block is in good condition, a clean-up and fresh hone is all that will be needed. From there, order your pistons in 81mm form. NOT 81.5mm. Its also a good idea to have the rods shot-peened to make them stronger. As far as the rest, just replace the main and rod bearings, new rear main seal, new oil pump and water pump, both from a 96+ gsr so you can use the gsr timing belt.

i know where i said 81.5mm i just like bigger lol. got a 85mm once melted valves and pistons only had one run on it

 

[JoshuaH]

Ls Vtec

How do the Ctr Pistons have more compresssion than Itr's? I looked at some reference material and the Itr engine has more compression than the Ctr. I also noticed that the dome on the Ctr piston's are bigger than the Itr but i dont really know how that shit works. I thought the bigger dome the more compression.

 

[Mike_995]

Yes, the C5 does have higher comp then a b16, because the b16 head has a larger combustion chamber volume, the p30 JDM b16 pistons actually have a higher piston dome volume, than the ITR pistons. The difference between compression is really minor, and probably not enough for you to even notice a difference. I say stick with the p30's. My build with ITR pistons yeilds 11.74:1 comp because I had 10 thou shaved off of the head. The only reason why ITR pistons are in there is because the block I bought had them in it.
Heres a good B-series compression calculator for you to play with the numbers.

Compression Calculator - Honda, Acura Tech Website, tutorials, tuning and HOW-TO's. Drag racing, street racing, road racing - C-speedracing.com