I've been kicking around the idea of doing an NA build for my 2.4, and would like some specific suggestions on how to reach my goal.

Goal: 220 WHP

Current Mods:
ZZP Shorty Header
Monza 2.5" Catback
Injen CAI
Custom Tune

(This is an NA discussion, I don't want to hear about Nitrous, or Forced Induction)

 

cams and some exhaust porting should get you a decent amount.

also looks like you need a downpipe. some larger injectors wouldnt hurt since i believe the IDC on a 2.4 is about 100% from the factory on those tiny ass 27lb injectors.

 

Port and polish the head, cams, 3 angle valve job with the largest valves you can stuff in the head, ported header, 2.5 inch DP, hi flow cat, 2.5 inch exhaust, a compression bump to 11 to 1 would help too. And don't forget the injectors.

 

like he said^^^cams, DP, a slightly different tune, 30-35lb injectors
there is a guy on here somewhere that is claiming 215hp with a tune, full exhaust, intake and cams on the LE5, so who knows

 

F' the cat! haha. i just 'deleted' my so called "high flow" cat and the car runs so much better.

 

Some areas require a cat and look for it. If you run a 3 inch hi flow cat it'llflow more then 100% of the 2.5 system and cause no restriction at all.

 

Not to sure if this would work with this motor but has anyone thought of an ITB setup?

 

You won't break 200whp without head work.

Look into over sized valves along with a 3-angle valve job.

Ecotec heads flow like poo, should see a nice gain from P+P along with the 3-angle valve job.

I don't think higher compression is needed, but some more aggressive cams/spring/retainers are a must.

In a nutshell:

Add a DP and complete new head and you'd(and me) would be there...with the cams you can finally put on the LSJ injectors it seems that every 2.4 guy has laying around

That has been discussed on here the other day and extensively over on ecotecforum...short answer no...long answer, I worked all night and don't feel like typing

 

thats fine just thought id throw it out there. Might do a lil searching later if Im feeling ambitious

 

Lets get a little more specific what cams, compression, 32# injectors?

Where would I get my head ported?
Raise the rev limiter, to what RPM, what would be required?

 

The springs from what I've been told are good til 6800....I would say that you would have to rev to about 7500 with some cams.


Any machine shop with 3-angle your head with a P+P

Cams?

Stock regrinds, ask redfocz he knows a place in FL that will buy, make said grind for like 600 bucks.

If you are going to do the head...make that ******* thing bullet proof

 

I wouldn't say any machine shop, go with one that has experence with doing aluminum heads and race heads. If you were local I'd recomend Ladds Head Porting as they have been around since the 60's and doing race stuff and have TONS of experence in aluminum head work.

As for the cams I'm not gonna recomend any old cam but I will tell you what to look for. Higher lift will get you off the line faster, more duration will give you more top end power. But one often over looked aspect is the center line the cams are ground and set up on. The lower the center line # the more cylinder presure you'll bleed off at idle alowing more compression and yeilding a loppy idle. A higher center line # will yeild more cylinder presure and make the most of the compression you currnetly have. Now if you were building a SBC I'd be able to give you specs depending on what you want off the top of my head! ECOTEC's not so much tho

A great street cam for a SBC would have lift around the .490 range duration in the .230 @50 range and a center line of 114. Plenty of lift, good duration without the need of a huge stall and a center line of 114 with 10 to1 compression would get you over 220 psi of cranking compression.

 

Cams, valves, valve springs, retainers, 3 ange vavle job... 10:1 pistons, might as well do rods. That outta' do it!

And then a damn good tune!

 

10:1? our car has 10.4:1 stock. I'd say 10.75:1 would be great!

 

Oh, whoops! I forgot that part..... or do some 11:1's.... (sorry had LSJ/LNF figures in me' head)

 

You could always save up for the Mild 2.4 engine that they clame to handle up to 300 WHP from JBP.

 

higher compression...

 

dont waste ur money ryan...the money ur gonna spend to build this thing u can buy an egg and have it fully built with way more hp..for some reason (not my guy) but i have notice people jack up prices because "ecotec" engine is way different than other engines...but thats just IMO

 

Ummm... I hope that everyone saying 'port the head' understands N/A head porting.
It's not like forced induction porting.

You won't want to bore out the port at all... just smooth it out and get rid of anything that could upset the air flow. N/A performance relies more on intake air velocity, as opposed to intake runner area.

 

I know you're just kicking the idea around, but how are you gonna get around while your car is getting worked on?

 

Not sure if you would want to but nitrous would be another idea.

 

reading>you

haha anyway, sounds like a good plan, but in the end i honestly dont think it would be worth all the money/hassle. your car would be down for awhile, things may go wrong, etc etc. stick with full bolt on's and a wickedtoon man. thats just my opinion.

 

I have some stock lsj injectors if you want them. Talk to Onyxd04Redline. He did a 2.4 build in his old redline i believe. Higher compression and the whole works.

 

woops, didn't read that far lol

 

Im looking to do a similar build, but my goal is just 200 WHP. Im tossing around the idea of that alcohol/methyl kit (http://www.alcoholinjectionsystems.c...c25/index.html) that CSM made a thread about. I need to learn more about it but some of my mechanic friends are saying that the 2.4 could potentially see 12-16 WHP from this mod and a nice tune.