ls3? Yeahhh????

 

I am sorta building a 2.4 NA motor (2.4 bottom end, 2.0 head), should hopefully put down 205-215whp and put my car into the 12's, I have a thread in "Advanced Performace" if you want some ideas.

My ultimate NA Ecotec build tho, if money is no option:

2.4 Block
Stock Crank
Custom Long Rods (to get away from the horseshit stock 1.45 RS Ratio)
Darton Sleaves
Custom 13:1 Pistons (90mm Bore with Raised Wrist Pins)
AMMFAB Ported LSJ Head
Custom Cometic HG
Custom Cams (500-525 lift, lots of duration)
AMMFAB Long Tube Stepped Header
Kinsler Performance ITB's With Secondary Injectors
Tuned on Megasquirt

That should be good for around 300whp.

 

hey newt, ive always been curious with itbs. how do you maf tune with them? do you still have a intake manifold and run them like the e46 m3? or do you have them running with no manifold or filter?

edit: i was wondering how you maf tune without an intake manifold if thats how your running them? also im assuming you converted to drive by cable?

 

man that sounds absolutely delicious lol somebody give me an amen ha ha

 

I can answer that one, its a bit comblex so I will explain it like this, if you want to run ITB with a MAF sensor you need an "air box" the air box conects to the mouth of the TBs so all your air flow gos through the air box before it gets to the TBs you simply conect the MAF sensor to the intake of the air box check this link out there are some pictures that might help Borla-TWM Induction - Air Boxes (423) 979-4045
also there are drive by wire ITBs available
if you want to have a MAP sensor then you have a vacume rail that conects to each intake runner after each TB http://www.prestostore.com/catalog.p...&or=&preview=Y
and the Air Box previously mentioned can be used with a filter but with ITB they are most comanly used without a filter

 

wow thats sick, thanks man. love learning somethin new. ive seen a few cars with open itb's but always wondered how they tuned

 

Yes, best way to eliminate the MAF and switch over to MAP based speed density tuning, hence the use of a standalone.

 

Yeah he has a point about the MAF to MAP, BUT... MAP measures Preasure or vacume in psi and while this method has worked for years it only measures resistance not actual air flow a MAF is exactly what it is A mass air flow sensor, that being said for precise tuning which it what would be needed for a serious build MAF is beter then MAP in terms of accuracy and precision
All the same which ever is used I think a standalone is needed for exact control over serious builds

 

you guys fill me with ideas. my shrink says you guys arent good for my "emotional development"

 

the only reason to goto aftermarket rotating assembly would be to get LIGHTER parts... everyone ***** up and puts heavy ass H-Beam rods and big heavy thick deck pistons in motors that they plan to run N/A and wonder why they lost 10-15hp over their stock motor...

port the snot out of our terrible head, find some lightweight pistons that are gas ported since you'll be north of 7000, lightweight I-beam rods, have the crank knife edged, run a crank scraper, then have cams made to match your application. obviously you'd run either an ITB setup or have a sheetmetal intake manifold made, probably use something like an LS4 TB or maybe even a 90mm LS2 TB if the ECU you're using to control it has the ability to change that table. if you want to be cheap go with the ZZP long tube otherwise have one made for your specific application as in a tri-y with the lengths of the primaries and secondaries calculated out... you wouldnt be running pump gas or E85 in this anyways so get the compression as high as possible, probably in the 14:1 range and run something like C12 or possibly something oxygenated, i believe most of the oxygenated fuels carry 6% o2.

i can see that making 350ish hp if you could keep the valvetrain together turning 8500-9000

 

if you're at the level where that matters you're tuning either one at the track for the conditions at that moment anyways. MAP setups offer once less part to fail and one less possible restriction.

 

I really don't see MAF as a nessecity, every big HP all-motor Honda tunes off a MAP with speed density and its working fine for them.


While I don't disagree with selecting lighter components for the bottom end, selecting aftermarket rods/pistons to increase the R/S angle would be my #1 priority when ordering an aftermarket bottom end.

The R/S angle of a 2.4 is 1.45, which is horible, ideal is up near 1.75. The rod angle and piston speed associated with a 1.45 R/S ratio is crazy, you will never get a stock bttom end LE5 to rev to 9000rpm with the stock rod/piston length combo and have it last.

Not to mention it will be hard to build high RPM power with the R/S ratio so high, reduced dwell time, increase piston side wall loading and increased piston speeds are all negative side effects of having a low R/S ratio.

All said and done, the stock LE5 bottom end geomotry is a horrible set-up for a BIG HP all-motor car, you would be better off starting with the LSJ bottom end if you wanted to build a big HP NA motor and didn't want to get into the bottom end geomotry.

 

GMTunerSource.com - ECOtec Race Engines Win in Powerboat Racing

Maybe it can help

 

There is a couple of spec (basic) in gmpp build book

 

Wow 340 hp na from the 2.2! That's impressive!

 

In the GM performace built book they claim 325 hp on e85 and 340hp on methanol

 

http://gmtunersource.com/racertech/e...ition/download. Page 27

 

2.4 block
2.0 crank
custom rods and LNF pistons
LNF head (ported by someone who knows how to port DI heads for NA, aka like 3 people in the world)
LNF computer
custom cams (by someone who knows how to make cams for DI heads for NA, aka like 3 people in the world)
custom long tube stepped header
custom equal length intake manifold
Stay MAF, because its better than MAP, though if you have tuning problems you may have to switch to a Bosch or McClaren computer that can do the DI and VVT with a custom operating system that lets you run alpha-n at low throttle positions.
Need to be tuned on the dyno for sure.

Thanks to the DI and the VVT you will be able to get a very broad torque curve, like one seen on a boosted engine and I would say you could still manage to get in the 250 hp neighborhood.


Earlier in the thread someone wondered why hondas can build crazy na engines, its because; 1. Their heads flow more stock, and 2 their heads flow more ported.