500horse

As the title says Im rebuilding a 1.8 in my 96 miata. I will most likley buy a rebuild kit from FM. What I want to know is I would like to get a little better performance out of the rebuild. I do not have the money right now for a turbo. So I was wondering what I can do to get the compression up like decking the head if I did that what would the compression ratio go up to and
would there be any real preformance gain? Another words is the cost benefit worth it? Also was thinking about haveing the head ported and polished and a good valve job done. So again is there any real preformance gains to be had buy increasing compression and doing the port and polish? Any help or advice would be great or if anyone knows of someone who has already done it that I could talk to would be great.

miata2fast

iTrader: (2)

Hmmm. Am I to assume you will be reusing your stock pistons?

You have to honestly ask yourself what kind of mods you know you will do later down the road. Also what kind of budget you have.

If you have not already invested in any other mods, than I would say do not do any port work. You will gain more performance with say an exhaust system and light flywheel than you would with a ported and decked head and no other mods. The compression will not go up that much, and it is better to do more exotic mods when you have already done the other basic mods.

500horse

I have all spec miata upgrades such as clutch short throw shifter all suspension rollbar and I have exaust as well. no engine stuff at all.I will be replacing the pistons but not the rods. I already have new timing belt and water pump.

shuiend

iTrader: (24)

Honestly if you are going into the engine for whatever reason, you need to throw in a cheap set of $300 forged rods. The rods are the weak link of the BP motor, so replacing them will give you a lot of future security.

mx594m

iTrader: (1)

if forced induction is in your future, do not go with the lightest flywheel, but do think ATI dampener

VitaminD

iTrader: (14)

I would skip the FM rebuild kit those parts can be bought for less money.

y8s

iTrader: (8)

wiggity what?

there's no penalty for a super light flywheel (OR clutch) in our cars.

mx594m

iTrader: (1)

I don't understand wiggity, but

lighter flywheel means quicker spin down for engine when shifting [unless some minimum lower rev limit implemented by engine management]

heaver flywheel means revs are higher, more exhaust gas being pumped to turbo during shifting

Renown Performance

iTrader: (8)

I highly recommend getting a port job on the head. We have multiple Miata heads in stock right now, and every time I look at one I am amazed at how inefficient they are. Currently we are in the middle of performing a Renown stage 2 and a Renown Stage 4 head for two Miata customers. These customers know they will need this modification to help achieve a more responsive engine.

Don't look at porting the head for more power but also look at it to help you build a better power band and a more efficient engine. We don't believe your engine should struggle to breath. in allowing your engine to struggle breathing.

whispering eye

iTrader: (1)

I think that before we start debating on what flywheel, you really should figure out what the car is being used for.

Also If you need rebuild parts let us know.

mx594m

iTrader: (1)

I could not agree more, but in the original message the OP stated

so the OP has not ruled out a move to a turbo in the future

I am just suggesting careful thinking today about mods adopted now that will not have to be changed later; the flywheel being one [even FM cautions about/against the lightest flywheel for turbo/SC applications]
another is the compression ratio if after market pistons are installed [forgoing high CR pistons if forced induction is in the future]

so we are back to the original question for the OP

is this an engine that will always be normally aspired?
or is forced induction the final end point?

miata2fast

iTrader: (2)

Are you the worlds slowest shifter?

Sounds like you are speculating and not talking with experience. Y8s as well as many others here have light flywheels on their turbo cars, and never experienced this problem.

If anything, the minimal amount of rpm drop will be offset by the gains in a light flywheel's ability to rev faster, resulting in proper exhaust gas pumping you speak of.

Put one on for yourself. I have my doubts you would remove it once you saw the benefits.

mx594m

iTrader: (1)

well I guess I must be a slow shifter

and I have installed a lighter flywheel, and thus have the experience

but this thread is not about me, or you, or y8, or etal;
instead the OP asked for input about an engine rebuild
I offer my input - think hard about installing the lightest flywheel and think hard about raising the compression ratio IF a turbo is the end point

nugh said, have a good day

miata2fast

iTrader: (2)

I should not have said the comment about the worlds slowest shifter. Sorry.

The FM happy meal is hardly considered a very light flywheel so no, you do not have experience with one. Do not take everything that FM says as gospel.

Lighter flywheels do take more practice and skill to drive gracefully, but in no way would it ever be slower regardless of the induction methods.

mx594m

iTrader: (1)

no offense taken, i know that i am slow
I did opt for the lighter flywheel with the happy meal, just not the lightest

what kind of whp are you recording with that 12:1 CR?
what have you done on the exhaust side?

500horse

Thank you all. I will be using the car for track days and driving back and forth to work sometimes. I will not be adding forced induction. Eventually I will be doing a motor swap. But that will be way down the road. I really just want a fresh motor that has a little more umph with as little money as I can. I also have a 2011 Mustang GT that I am doing FI so I dont have much money to throw at the miata.

whispering eye

iTrader: (1)

well if the car is used for track i would say a lighter weight fly wheel will work great.