Chuckles

Hello,

I am looking to do some upgrades over the next couple of years to my LS2 Miata. My current plan is to do:

1) This year: Heads/Intake from an LS3/L92

2) Cam the following year.

My questions are regarding the first point. What kind of realistic power increase can I see with milled LS3 heads (maintain compression ratio) and intake with the stock LS2 cam? I will obviously have a professional tune completed.

Is there any harm or negatives to running this configuration until I can manage the cam install in a years time?

A primary reason for not performing the cam install at the same time is due to the fact I have moved and lost my large garage space. To install the cam I will need to drop the engine at which time I have some other areas to tackle. Realistically this can't happen this year.

Tainted

iTrader: (9)

yea, dont get LS3 heads.

PTV clearance is limited, and you wont be able to mill much for compression, and you have valve shrouding.

Get an ls6 head or step up to some real heads.


but if youre set on this, then the ls2 cam will just suck. it'll work, but you arent gonna get very much gain.

WKMCD

iTrader: (2)

I think it's worth it. You should pickup 15-20 simply because the L76/LS3 intake is so much better than the LS2 intake. The heads are also much better. If/when you add an approriate cam you're going to have to limit overlap or pull the heads and flycut the pistons. Shouldn't be a problem if you keep the cam small.

FWIW: I've been working with these heads since 2006 in many different configurations.

Just my $.02

george g

iTrader: (12)

Ls2s already have a 243 head. I see you're building a 408 will ls3 heads, do you really think 30 thousands is all that much more clearance?Just fulll of contradictions aren't you.

Tainted

iTrader: (9)

for starters my heads arent LS3 GM castings, they are AFTERMARKET

Not only do they have 0.40 more PTV clearance, but splayed valve angles, and smaller than stock runners.

hows that for contradicting?

Tainted

iTrader: (9)

Here, read these two threads, its a good starting point as to why you shouldnt use the ls3 heads.

https://ls1tech.com/forums/dynamomet...flow-235s.html


https://ls1tech.com/forums/dynamomet...k-results.html

WKMCD

iTrader: (2)

Yup! Lots of threads proving that people don't know how to deal with these heads.

It's just much easier to keep puking up internet BS than actually do something original and make it work.

george g

iTrader: (12)

Too many parts where changed at one time to prove anything.If he would have put a ported fast 102 on the ls3 heads he would have been over 500.I think for another $3,000 dollars worth of parts, 30 hp wasn't worth it. When you show me a direct swap, same intake ,same day ,same dyno comparrison I might believe it. My 408 with sdpc ls3 heads made 506 hp with a cam designed for a 6.0 with ported 243 ai heads and that was letting off at 5,800 due to junk springs that I had on the heads and a stock ls3 intake. So you showed me a low number ls3 head and I showed you a higher number, who's right?

samckitt

iTrader: (5)

Isn't the L76 of the G8 basically an LS2 with LS3 heads?

Tainted

iTrader: (9)

L92 heads if you wanna be exact.


The point im proving here is that unless yoir entire setup is based around the ls3 stuff its not going to perform well. Especially on stock cube cars, the reason they work better on larger cube cars is the fact they can move that amount of air. And its not all about those flow numbers either.
I did a whole **** TON of research before I bought my heads, I talked to every sponsor and head guy you can think of, and decided for my budget, that these would be the best performing and I have high hopes for them.

Everyone can do what you want. The people who can actualy back up their claims are the ones I took advice from. Ls3 stuff may flow good, but with you smaller bore folks and stock cubes you really arent doing yourself any favors. Take it with a grain of salt yall do what ya want.

WKMCD

iTrader: (2)

Dude, I've been working with the L92/LS3 heads since '06 and making them work when everyone was still saying they wouldn't. So you talk to people and read some and now your a ******* expert? You're a post ***** plain and simple. You post in every ******* thread as if you know WFT you're talking about. You are single handedly making this forum more stupid on a daily basis...

Tainted

iTrader: (9)

Yup and theres plenty of people that praise these ls3 heads, people get them, find out they are somewhat limited and get a shitty cam and then are disappointed.

I didnt say they couldnt make power, I suggested that hed be better off staying cathedral, and im sticking with that suggestion.

This war has been going on forever now between cathedral amd rectangle. Theres some killer combos out there with both setups.

And no one has to take my advice, but ive got more knowledge than a lot of others here. Im by absolutely no means an expert, but Ive done a whole lot of reading over the past ohh what.. 7 years now..? And ive also had plenty of hands on experience too.

So, anyone that doesnt like it, doesnt have to read ot, skip over it. But im going to be here and continue posting, reading, learning, and trying to help others too.

Thanks

WKMCD

iTrader: (2)

So you're doing a service by propogating internet BS?

Thanks for proving my point. BTW: People are laughing at you and you're too stupid to even know it.

Tainted

iTrader: (9)

Ok, so you've made your point and we can move along then right?

LPE 403

iTrader: (6)

Lmfao.....you have any "blue prints" for all that L92 magic?

Chuckles

Thanks for the advice: I am currently debating the following setup...

LS3 Heads Milled 0.020"
Spins' 230/234 114+2
Stock LS3 Intake
Ls2 TB

Should be good for mid 400's.

Tainted

iTrader: (9)

I think you can do it!

Scoggin Dickey

iTrader: (34)

Comparing stock casting LS3 heads to big name aftermarket cathedral port heads is not exactly a relevant comparison anyways. If you want max power without a budget, sure those can be a better option depending on the goal. on a budget and for running a smallish cam? Ported LS3 heads reign supreme. You can make great cam only HP with budget cathedral port heads, but it takes more cam to do it than it does with a proper cam and LS3 heads. You simply don't make the rwhp with a small cam and budget friendly factory casting cathedral port heads that you do with tiny cams and LS3 heads.

Back on the topic at hand since the OP asked a specific question, power gains will exist but will be minimal while you are running a stock LS2 cam. If you are going ot mill the heads, please go ahead and flycut the pistons while doing the swap. It will be well worth it with your final setup.