Has anyone done a good NA build on their 2.4L cobalt?

 

i've always thought of that... i wonder how high a 2.4L could rev? it would take some work, but a different set of cams, lifters, rockers, springs, and lightweight valves, and you could bump the redline up.

 

I wa one of the first to do anything NA on these.

 

g5mike what are you sitting at for HP & Torque with your mods?

 

You don't necessarily need to rev the **** out of the engine to make power

N/A Builds are all the same no matter what platform engine you have, you just have to understand where exactly you're trying to have your powerband and how much money you're realistically trying to invest.

Most of the work will be done in a machine shop for the most part so get ready to dish out some cash unless you got some decent hook ups.

If you do decide to raise the limiter, make sure your springs are capable of compressing and de-compressing properly otherwise they'll cause what is known as valve float. Also, when you do rev exceptionally higher, you need to increase the amount of air being drawn in. Understand that a engine is a large air pump and relies hugely (especially on a naturally aspirated engine) on scavenging effects and air velocity. Don't think that making things bigger or getting a "bigger" profile camshaft will necessarily be the best for your specific setup.

Increasing the bore will increase cylinder filling but you have to able to draw in a sufficient amount of air. If you're revving 1500 more RPMs, you want to make those RPMs be useful, not wasteful. You could get HP Tuners and rev 1500 more RPMs (1500 is just a example fyi) and gain nothing from it. Your powerband would dip down. Why? You're not drawing in enough air for the increased amount of intake strokes (remember, for every engine revolution, there is a intake stroke where it's ingesting air) and also your fuel tables are setup to keep a steady fuel delivery into the cylinders that would be beneficial to yourself.

Raise the compression, bore the cylinders a bit (well sleeves), slight head porting (example: 3 angle valve job), excellent tuning, a step colder spark plugs, knife edging the crankshaft, stronger connecting rods, balance the engine and the list goes on.

You just have to decide the specifics of what you feel comfortable doing.

 

not worth it imo unless you are trying to race in a n/a 4 cylinder class. If you wanna be fast with a 4 cylinder coupe the you need forced induction. the cost to do a n/a build is way higher than turbocharging.

 

what exactly is involved in an 'NA build'? i am not following the term

 

My advice would be do all the bolt ons you can, then port the head a little and get a tune. That should be good enough for you and good enough to put you in the 14's too.

 

by N/A he means Naturally Aspirated.


that means without the use of nitrous, supercharger, or turbocharger.

 

Bolt on's and a tune should get you in the 14's head work should be mid 14's

 

well if you order the vector tune for the 2.4 it puts the redline at 7,000

also alot of poeple have been running 15.0s and 15.1s with this tune and an intake.. so im going to be getting this and a bunch of other supporting mods. but in the end im most likely going to put a nitrious kit on (50 dry shot) to get to low 14s all said and done.

 

I have a pretty good setup now. cams, cai, motor mounts, header down pipe, corsa sport exhaust, intake manifold, hp tuners, stage two exedy clutch. and soon to come a hahns turbo kit.

 

If i HAD to build a 4cyl N/A i would do it like this..

11.5:1 pistons
Race ported head
Agressive cams
Header
DP
Catback
CAI
Tuning

Would be fun.

 

Yeah i get the NA part. but what is with the 'build' term why post saying 'someone should do a NA build' when a lot of people are modding their NA's, more some than others?

I don't get this thread

 

Yeah, but when most people talk about NA builds. They are talking about headwork, porting polishing, cams, raised compression and so on. What everyone else on this site myself included have done is basic bolt on’s. With basic bolt on’s you are not adding power but only allowing you engine to be more efficient which only lets the motor breath easier.

 

* see post above (REDFOCZ)

 

Well as of now I have my CAI/Header/DP/Hiflow Cat/and catback and a tune. Any ideas what would be easiest thing to do next?

 

Im in the same spot as you
I guess there suspension and brakes.

 

NO! Need horsepowerrrrrrr lol.

 

I would say brakes, I am running out of **** to do too lol.

 

Neon adds 40whp I heard...

 

headwork on a 2.4 would be like throwing ur money out the window ur gonna spend 3-4 grand for about 2 to 5 hp. think about it emissions and fuel econ gm engineers already have the head flowing pretty much as good as its going to.i would prob go for a longer duration cam and not worry to much about lift . spend ur money on light weight and balancing the inturnals and reduce as much rotating mass as possible. like a lightwaight fly wheel . the less rotating mass the faster the engine responds like a formula one race car. less rotating mass the more rmp the wider and longer the power band can potentally be but it a fine line of getting it right or getting it wrong. best bet for a n/a is find a good rep racing engine shop and about 8-10grand and let them figure out the math.