Im not sure if this is for you, but it’s definitely for the engineering nerd who devours numbers like cake, and has an open minded sincere appreciation for a proper Ecotec build with technical specs that will help you understand why a change in displacement might be for you.

You can choose 2; reliable, fast, cheap. Most people are not looking to go the route of a full engine build, but if your like me then you choose reliable and fast. What happens next is a project. And if the sound of this excites then the information I put in this article is for you.

Just imagine being on the highway pulling up to a Mid engine Corvette, give a look drop it down into gear, you both take off! The corvette got the jump but you start reeling him back look down at the tach it’s buried in the red, you shift into 3rd, he jumps slightly out from your shift, but this time you reel him in much harder. Your at the top of 3rd and you have his front bumper at your wheel well, the corvettes nose drops and you also back off. You both are well above the posted speed limit. Your senses fully engaged as you come back from the massive sound of 1000HP combined both on song side by side. You each slow down, you have a sh*t eatin grin, you look to see his face in astonishment..he gives you a thumbs up, you can see him laughing, you smile and you each continue on your way.

There is too little information out there for Ecotec guys. Those wanting to move to a better option for massive power in the Blown 4 cylinder world, I would say 500whp plus, this is especially for them!! Turbo guys will still appreciate bc of the engine technical tidbits, and there’s a lot! Enough let’s do it!

I focus on the 2.4L block with lsj head. This combo has been proven to reach 600whp with the newer GM gen3 blocks. Here is 3 reasons I will make the switch.

1. I will be staying Supercharged-

After making 424 whp on a 1320 TVS, I thought it was enough but then realized, in this ever changing world of direct injected vvt v8’s and twin turbo I6 and V6’s it’s tough to stay ahead when all they need is a tune and maybe cams.
Our heads are pretty inefficient compared to a Honda K20A2, and it’s only after very generous head porting you can see increases of 35% on the intake and 60% on the exhaust side

Stock LSJ head flow:
247cfm intake @.450in and
163.5cfm exhaust @.450in
Stock K20A2 head flow:
301cfm intake @.450in and
205cfm exhaust @.450in

The reason I’ve compared to a Honda K20A2 is bc of its ability to flow stock is pretty incredible, and is one of the better heads in the Honda lineup. Also the stock intake and exhaust valve size is identical.

However if you add the general estimate of 35% intake gain of a port job from Cat V performance to a stock LSJ head you will get roughly
Ported gains of:
333.5cfm intake @.450-.5 and
then add estimated 60% exhaust gain you get
261cfm exhaust @.450-.5

If you take the head flow numbers, compression ratio and cam spec of the race lobe during VTEC it is no wonder a K20a2 can make Impressive N/A power.

To be fair a ported K20a2 head then makes even more gains on top of its already superior flow add to that a 5 angle valve job and +1 valves they are making 360+CFM, 350+whp on 2.4 NA without a sweat

For an LSJ ported head to have similar performance to a stock K20A2 head one would need a port and polish job along with larger valves and a stg3/4 cam at the least or custom grind to make the best power up top. Head vendors for the Ecotec have done +1mm and some have claimed to go further then that to make brutally fast Ecotec NA 2.4’s used in auto circle track racing.

The reason for proper head build is to make the TVS 1320 really shine. The capability for a blown car is through head flow. And the capability of a blown car over larger Turbo is throttle linearity.
Put Simply a supercharged car has zero lag and acts like a N/A car with more power. Unfortunately There is no beating a turbo setup bc of free HP compared to a blower sapping HP from the crank just to run itself. But there is nothing like the intoxication of blower whine in my opinion
I do more roadcourse then autox and like to drag every once in a while. Having a fun capable fwd Screamin Blown Bruiser on track has always been very unique and a personal goal of mine.

To make HP you build the head

To keep HP you build the block

It’s that simple, but the complication comes in at making HP at high RPM and knowing how that can effect your rotating assembly. Including your trans
Which lead me to my next reason

2. Keeping a manual Transmission-

Most sought after tuner cars will be manual. The auto box will make many purists cringe at the sight of a auto Supra on the street.

Nice!! Supra!! First thing they will look for in the interior is the shifter.

A person that can row their own gears makes for more interesting drivers. We know a race can be won or lost from a missed shift or from someone who doesn’t know how to shift in the powerband of their own car, ie my 1jz sc300 had better trap speeds when shifting @6000 instead of redline, bc of the stock turbos’s runnning out of steam, unfortunately auto 1jz guys couldn’t shift at lower rpms.

While a synchronized helical gear transmission works great in a street setup, things can get a little more tricky at high rpm’s. Once you start getting into the 8500 rpm and up club shifting a helical cut geared car starts getting rough on the synchronizers of a manual transmission and shift lockout at high rpms can ruin a perfect run.
There are straight cut gears, but I can not as of now find any aftermarket company’s that do straight cut on f23,f35, or f40 transmissions. I wouldn’t go this route, bc of the straight cut gear whine, and I would still like to drive this car on road trip, gear whine is a no-go

Bc of the high RPM needed to make more power with a smaller displacement engine, it can become difficult to put down reliable power shifting through high RPM’s in a 2.0 or 2.1L build

Lets take for example my car making 424 whp on a 2.0 build, with all other supporting mods aside we focus on displacement increase only to 2.4L or more accurately 1998cc to 2384cc.

History has shown that an increase in stroke to increase displacement, will give more torque and supply more hp in a linear fashion, think 1 and 2jz, 4.8 and 5.3 LS engines.

With that we have:

2384cc divided by 1998cc = 1.1932
424whp multiplied by 1.1932 = 506whp

It is NOT just that simple though. We have increased the combustion area only and now need to work on making the rest of the engine flow the required CFM’s to reach that desired level of power. Which means head flow, intake and exhaust flow and smoothing any turbulence in between these transitions, and most importantly for me intake manifold port matching to the head.

With the increase in displacement of stroke:
from 86mm to 98mm and increase in bore
from 86mm to 88mm,
we now have a larger piston that needs to travel further inside the combustion chamber.

This means the mass and speed of the piston have increased
This places more inertia at 6,000 rpm on the rotating assembly then it previously did running a lighter piston traveling a shorter distance inside the chamber.

At 3,000rpm and 6,000rpm the load of the reciprocating assembly quadruples.

With this increase in hp between displacement, we have a decrease in ability to hold the heavier faster moving components together at the same high RPMs.
Reliability comes into play and we can fix this problem with heavier duty wrist pins, rods, rod bolts and race oil.

Or we can run the engine at lower Max RPM’s

With my ZZP Stg 3 cams I saw max hp @7900RPM.
I was not shifting until 83-8500 RPM bc I was not losing much power above 7900RPM’s. By staying in gear you have better gear multiplication to propel you forward then in the next available gear.
BUT I would rather make the most out of the powerband and shift at the
highest hp the engine makes.
With the 2.4 you are forced to lower the RPM’s to play safe bc of piston inertia.

Internal engine calculation for the
2.0L @8500 and
2.4 L @8200
Lets see if we can find a safer engine RPM for our “big block” Ecotec

The good stuff!!! I’ll be using Diamond pistons, K1 and Molnar connecting rod weights and lengths

I start with Piston speed- the speed of the piston traveling up and down in the bore
It is a good rule of thumb to not exceed 5000 FPM for forged pistons

Avg Piston Speed in FPM(feet per minute=(strokex2xRPM)/12

2.0L-(3.386x2x8500RPM)/12=4796FPM
2.4L-
(3.858x2x8200RPM)/12= 5272FPM

HMMM 300 RPM less but higher AVG piston speed by 476FPM and already past 5000FPM
Lets move to max piston speed at Redline
F1 engine has a max piston speed of 7536FPM, lets use that as a target.

Max piston speed ((Stroke x pi)/12)RPM

2.0L- ((3.386x3.1416)/12)8500=7534FPM
Just under the F1 target!! For roadcourse work this is a perfect RPM.
2.4L- ((3.858x3.1416)/12)8200=8282FPM

At max RPM’s we see a difference of 748FPM. This might be okay at short bursts but for longevity this could cause metal fatigue.

However this is piston speed only accounting for the increase of stroke.
It does not tell the story of the extra weight of the piston from the increased bore, or how the length of the shorter connecting rod also comes into play.

Lets get into inertia- the effect of mass times acceleration and the reason why forces in an engine quadruple from 3-6000RPM

Primary Inertia Force(lbs/sq in) .0000142 x Piston Weight(lbs) x RPM Sq x Stroke

2.0L- .0000142x.789255x72250000x3.386= 2742lbs
2.4L- .0000142x82012x67240000x3.858= 3021lbs

We have now lowered RPM by 300 but still see 10% more POTENTIAL inertia of the piston.

Now let’s find the inertia at Top dead center under the exhaust stroke!!
The most gruesome force put into your rotating assembly

Massive boost can bend your rods but Inertia can throw your piston through the head

There is no compressive forces of combustion to cushion the piston from the top during the exhaust stroke. This is also why an unloaded free-revving engine is very hard on engine components and oil. You have continuous max inertia applied to the piston every revolution compared to every other revolution bc of the 4 cycle engine process

This calculation incorporates the stroke of the SHORTER rod used in a 2.4L
WHILE also narrowing down the upward and downward force of inertia.

LONGER rods help cushion the excessive forces of stroke by decreasing inertia.
Put simply the change in direction of the piston is less abrupt with a longer connecting rod; less acceleration.

Primary Inertia Force w/ Rod Length factor (1/2 Stroke/rod length)(Primary Inertia Force)

2.0L- 1/2(3.386)/5.72835=.295(2741.77)= 808.8lbs

This is added and subtracted from Primary inertia force to END with

3550lbs of upward force and
1932lbs of downward force

2.4L- 1/2(3.858)/5.659=.341(3021.03)= 1029.8 lbs

A much larger number bc of a shorter rod, longer stroked, heavier piston.

4051lbs of upward force
1991lbs of downward force.

Now bc of the shorter connecting rod causing greater inertia,
the change in the 2.4L is a drastic 14% greater then that of the longer rod in the 2.0L.

After recalculating with several RPM numbers I came to the final conclusion of

A 7900RPM redline max for roadcourse use
This redline will give me the capability all the way up to the top of the Stg 3 cams output, w/o fatiguing engine internals much past my current 8500rpm setup

A 8200RPM redline max for drag and street use
This redline is harder on internals but the

Molnar connecting rods come with ARP2000 rod bolts, which are already an upgrade from the standard 8740. These have been proven time and time again in 9000rpm engines. Factoring That these bolts are good to
19,700lbs of inertia, and from our math earlier, we are only
@4051lbs that gives us a safety net of 486%. The general rule of thumb is to stay above
125% safety net, so no need to upgrade here.

Let’s take for example the Honda S2000 which had a redline of 8800rpm on its 2.0L, but later year models ditched the 2.0 for an increased stroke and used a 2.2L with redline of 8000rpm. In order to get the extra stroke Honda was forced to decrease the rod length thus even though an 800 rpm redline difference, the inertia was still higher in the 2.2L. Honda engineers took the risk for reward of more torque and power and we saw the 2.2L S2000’s have much better roadcourse and track numbers

The 2.0L was built by GM to be able to rev higher without throwing a piston into orbit which is why guys can run 9500RPM in built LSJ.
It is why GM went with the 2.0L setup to make 1400hp @11000rpm.
With this same theory of surviving at extreme HP levels at very high RPM’s it will survive at moderate HP levels at reasonable RPM’s, It is why their are unmolested 2.0L at 200k miles and beyond.

I make a great case almost to stay with the 2.0L! Ha! Maybe if I were turbo. But unfortunately I need to increase displacement to get the power I need, which leads me to the final reason

3. GM’s Gen 3 Sand casted and girdled blocks

These are excellent blocks used in the equinox, regal, terrain, and lacrosse. I believe the direct injected block Is the proper gen 3.
All internals can be built and specd to the 2.4L crank. The block does not show fatigue until well past 600whp. I have seen many question the stock cast crank but have heard of none, or when searching have not found any breaking to date.
In fact searches have shown cast cranks lasting past 35lbs of boost but forged rods bending due to extreme cylinder pressure.

I might need to run more then what the 1320 TVS will flow, which is roughly on par to:

565 CRANK HP or 497 whp with a built e85 k20. Or an Audi R8 V8 making no more then“+100whp past stock” which would be roughly 450-455awhp also roughly 565crank hp. Further research has not shown anything above this crank hp number.

When looking at blower efficiency chart it’s hard to understand why the 1320 doesn’t put out more, and it comes to power consumption from driving itself, in fact upwards of 20% can be sapped if out of the blower efficiency range, that means your engine’s combustion effect may be making power for
680hp but it is only showing
495whp on the Dyno.
This is why building an engine properly for a Blower set up is critical.
its why Blown LSJ’s have issues past 350whp while it takes 380-400whp before turbo guys had the same problem.

However to push the envelope to the limit their is the
TVS 1900. Capable of 700whp on a v8 and over 500whp on a k20 and 550whp on a k24. However of great interest is some guys running a
TVS2300 on built k24’s making over 600whp.

Pushing the TVS1320 to 500whp could prove difficult unless everything is perfect and possibly a chill box or killer chiller s/c kit is used.

Would a TVS1900 fit the bill for a 2.4L for 500whp, with a FULLY built head it could be done, but one would need to possibly move to a different intake manifold setup as the stock intake manifold most likely will limit them.

These 3 reasons are personal and some may consider biased, however some proof was researched based off of forums, some even from estimates in the case of lsj ported head flow from 2 different head builders in the Ecotec community.

But the math is there take it for what it is..

PS...please make this a sticky

 

Nice write up!

 

Did a couple updates for engine redline results, rod bolt strength compared to calculated engine inertia, and blower speed effects.

 

Havent gone over it but dont see much of a problem to make it a sticky unless another mod disagree then they can remove it

 

Looks like we're eyeballing similar paths, although I've been debating sticking with the 2.0 lately, partly for some of the reasons you've mentioned, partly for simplicity.

One of my problems being turbo, is oil feel and drain. The drain isn't that hard, but the feed presents questions, since they did away with the oil galley ports on the Gen 3's. I not only need a good pressured feed for the turbo, but also for the oil cooler, since the stock cooler ports also aren't even there. The ports can be machined out - I'm just not 100% sure I want to do that kind of experimentation right now. There's ports on the head and oil channels along the flywheel side of the block that I should be able to use, but some more investigation is needed. I have a Gen 3 2.4 block in my garage; I just need to spend some intimate time with it.

 

Don't the Gen 3 Ecotec blocks simply have a hard coating over the aluminum cylinder bores (instead of steel sleeves) that are far less durable concerning cylinder wear?

 

They're definitely sleeveless... and that was one of my concerns as well - longevity of the bore.

With that said, I haven't taken my bore gauge out yet, but the cylinders look good and I can still see the factory cross-hatch. My tendency is to doubt GM would go that route unless they had proven it could work. I'm just curious about how they'll hold power long term.

Does anyone know if they've got that route with any other engines? Have they made that move on any of the LSx engines? Questions to answer.

 

Many older gen 3 engines have now surpassed 150-200k, although there have been issues with timing and such, I’m sure Jeffrey Reiland might have a better answer on cobaltss gang. I’ve personally ran a gen 3 ldk block @22-26 psi since 2014 and other then blowing the return oil plug out the back 2 different times and popping a HG on a top end run it’s been great. I’ve roadcoursed the TVS up to 23000rpm blower speed many many times. Done half mile events, drag events, top speed runs in the middle of the desert and so on. The cylinder bores looked fresh when I took the head off to replace the HG, that was 3 years ago, and it had 3 years of abuse on it then.

 

USMC Get in contact with Alpha Motorsports Inc, they are the ones that run the gen 3 2.4 turbo and use the stock blocks and push em past 600whp, they are really nice dudes and even support our bois under SOCOM.

 

Checking in with a Gen 3 block and it made 444 whp @ 28 psi, turbro'd with LE5 "Stage 0.5" port work stock valves sizes and ZZP NA cams. So far it's alive, but have ring sealing issues across the board likely the out-of-spec custom pistons and the engine builders fault (me).

 

Ring issues? Like low compression numbers and a leak down you can hear from the oil cap? I’m using TotalSeal Rings and had an engine builder gap em for me, just installed the way he told me.

 

the ports on the head arent wise to use for the turbo feed. the oil feed between the block and the head has a restrictor to reduce oil flow to the head, as a result you generally dont see more than 30 psi at those oil ports. in the early days of the ecotec, myself and several others went through several turbos before discovering this being an issue. the oil pressure sensor port is another one i wouldnt use, if you follow the oil circuit diagrams you will find that this port is between the oil pump and the filter housing, meaning its unfiltered oil.

im not real familiar with the gen 3 blocks, all i know is they dont have the oil galley plugs above the balance shafts like the earlier blocks. you might be able to drill and tap the bottom of the oil filter housing for a fitting. another option would be to run the cbm oil filter bypass, this allows you to run a remote filter, and if you want, an oil-air cooler. you can also take oil off the remote filter housing to feed the turbo.

gm isnt the first to do this, porsche was doing this all the way back to the 70s. its called Nakasil. its also the same coating used on the rotor housings in a rotary engine. the idea behind it is sound, and bore wear isnt too much of an issue. the ls engines never used this (keep in mind the ls platform is no longer made), im not sure about the LT based engines.

 

Gen 3 2.4 blocks have steel liners.

About the oil feed, I drilled and tapped an oil gallery on the trans side of the block that feeds the head and used that to oil the turbo.

 

Pretty sure thats only on the 2.0 and from ive seen its not all of them. I could be wrong though as I only deal with the 2.4 stuff, but the 2.4 gen3 blocks I have are both steel lined.

 

I'm aware of most of things oil related things, which is why I'm quite concerned and not quite willing to experiment. There is a factory oil feed location, but it needs to be machined open, much like the factory oil drain. I know ZZP does it, but I don't know that I'm willing to have a local machine shop try it - especially with the risk involved from a single aluminum shaving getting stuck in the engine. Another member had a port drilled and tapped just below the head/block connection, to use as an oil feed.

I converted to turbo in 2009 and have always used the Oil Galley plugs, so I never had that issue. I do remember users using head ports though and being okay; I think you have to be running a DBB turbo though that requires restriction. Been a long time, so it's hard to remember.

I've seen Mongorat layout where he used plugs on the flywheel side to run an air-to-oil oil cooler from a Ford, so that isn't a huge issue.

I knew of Porsche doing something similar, but I wasn't 100% of GM's method. I also seem to recall that 996's, 986's, and 987's had problems with bore scoring, but iirc, it didn't affect the Turbo's because they had been treated differently. It's been a little while since I looked into the issue, so I'm sure I got some of the details wrong.

 

What block did you use? Mine is out of a 2011 Equinox, iirc... and it definitely looks like it doesn't have sleeves. There's a distinctly different look to it compared to my LSJ and LNF blocks.

 

Only 60% leakdown in 1,4 and 40% in 2,3 which slowly deteriorated since day 1, I've been monitoring constantly:
Long-story short, the custom pistons had ring grooves with 0 clearance that I didn't find out until 6 months later and JR didn't respond and I was in the middle of building the engine and trying to meet a deadline for the build so didn't want to deal with Diamond so I chucked the pistons up in the lathe and touched up the grooves. I beat the **** out of the engine too.

 

Interesting. I have an LEA block from a 2014 Terrain. I have another shortblock sitting in my garage that also has steel liners, but IDK what car it came out of.

If you plan on building one, Id recommend getting a steel lined one.

 

Interesting. My understand was that the LEA and LAF should be virtually the same shortblock - the LEA was just capable of running E85?

I'll look at my LAF block harder; there's a defined difference between Aluminum and Steel on the LSJ/LNF, and I didn't notice that on the LAF.

EDIT:
LAF block:

LSJ block:

Definitely no sleeves in my LAF

EDIT2: to go along with what I thought about LAF/LEA differences:

 

Lined with these? https://dartonsleeves.com/mid_02.html

 

Why would they go back to steel liners? I’ll need to verify if it’s the liner or coating block that made over 600whp, after doing a little research, it seems that LEA and LAF should both be aluminum, however 2.5L engines started with cylinder liners and forged crankshafts, but the block construction is totally different then a 2.4

 

I think maybe youre a bit confused.

Just because you cant see the partition from aluminum to steel at the top doesnt mean they arent steel. The sleeves are cast inside the block on a gen3 and arent removable like they were on previous blocks.

I had my block machined for the slightly larger pistons I put in it, and im pretty sure if it was coated I wouldnt have been able to do that. Easiest way to tell is go stick a magnet on it.

 

Interesting.

 

So I just went and checked my spare LEA block, and there was some surface rust on the walls. Definitely steel.

 

Here is a 2006 2.4 LE5 block for reference:

*it's not cracked and I suck at ridge reamer