Hey guys, i've got a 4th gen prelude i'm looking to turbo, and was basically wondering if anyone knew of what numbers you can make on stock internals, i'm only looking to make about 300-350hp and will probably end up purchasing forged rods and pistons anyways just to be on the safe side, and for the possibility of making more semi-reliably in the future, but for the sake of budget i'm curious what kind of power i can make without grenading the engine within the first week, this will be a mostly street car that might see a few events at the drag strip, any inputs are appreciated, thank you.

 

H23 has FRM liners like every other H series. Standard forged pistons will not work with them. To go with a forged bottom end the block will need to be sleeved with either full replacement sleeves or with just plain iron liners for low hp goal.

With that said 300whp is very safe for a healthy stock H/F series. 350whp is pushing the limits of reliability and some stock engines may tolerate it, some may not. You will need to be sure to use quality parts, have them properly installed, and then have the car tuned by a professional. Ultimately the tune will be the biggest deciding factor in the engine's lifespan after being turbocharged.

 

I was aware of the fact that that h23's aren't fond of forged pistons, do you have any clue how much it would cost to have a block resleeved? and if so how big of pistons should i use, i'm thinking i might push this motor to 500 for the track and that's partially why i want to spend so much on upgraded parts, i want to be able to do pull after pull with no thought for whether or not my engine's gonna toss a rod through the block

 

The non-vtec H23s are closed deck so you can likely get away with just replacing the FRM liners with iron ones. Darton sells a repair sleeve made of iron that is just pressed in after the FRM material is bored out. That would be the most cost effective way to do it. If I had to guess I would say $500-700 going that route depending on what your machine shop charges. If you want full aftermarket replacement sleeves you are talking about $1500-2000 just for the sleeving service.

 

So with the darton sleeves they should just be able to press them in inbetween the stock sleeves and wall of the block right? Sorry, if i'm being dumb, this is my first time looking into how to strengthen an engine and hondas aren't my norm. Appreciate your help so far, thank you!

 

The stock liner will have to be bored out, and the new liner installed in it's place. The darton dry sleeves with no flange are what I'm referring to. A typical machine shop can install them so you can run forged pistons relatively easily. Here is a link to what I'm talking about.

 

ohhhh okay, so if i were to run wet sleeves they'd just cnc out the factory liner, then install the sleeves

 

Yes. Boostedboiz did 700whp+ on the dry replacement liners with a closed deck block though. They are more than enough for 500.

 

Alright, and so the reason you can't run forged is because the stock liner, so with dry sleeves they'll just bore it out a bit, drop in the dry sleeves and that'll keep it from scoring and ruining the block, whereas before the aluminum block would get scored and sooner or later blow up, correct?

 

Dry liners, set of forged rods and pistons, valve springs at a minimum and you'll have a block ready for 500.

 

Okay, thank you so much for your help!