1.9L is better suited to a 376

 

How about if I got the stock blower ported?

 

🍿

 

I’m looking online but not too comfortable. Can someone point me in the right direction as far as vendors go

 

looking for clues

(sorry, just couldn't stop myself)



Too soon?

 

Lmbo

 

Don't change your pulley ratio. . .

With the larger volume engine (427) the little blower will fill the engine,
and make about the same HP. HP won't increase!

But the torque below the Peak HP will increase, as the volume
has changed, per the units of time / rpm.

Torque will increase, assuming you don't lower the static compression ratio.

If you desire to increase the HP, then put on the larger blower later if you wish.

**

Simple rule of thumb regarding calculating torque.

-on gasoline-
NA Engines; Multiply CID by static compression ratio, and divide by ten.
FI Engines; multiply that value by your density ratio.

Here the compression ratio is 10.0;1
The last value is the density ratio.

(427 * 10 / 10)= 427 lbs ft.
(427 * 10 / 10 * 1.41) = 602 lbs ft.
(427 * 10 / 10 * 1.75) = 747 lbs ft.

-move compression ratio up to 12.0:1
(427 * 12 / 10 * 1.75) = 897 lbs ft.

Here we see the importance of the increases of both the
static compression ratio, multiplied by the density ratio.

Big motor, roots blower, makes 'Big Torque' numbers!

Again, this is a simple 'Rule of Thumb' equation.
Kind of get's you into the ball park, but not exact.

And as the density ratio and compression ratio increase, so does ones octane level..lol

Cheers

 

Don't change your pulley ratio. . .

With the larger volume engine (427) the little blower will fill the engine,
and make about the same HP. HP won't increase!

But the torque below the Peak HP will increase, as the volume
has changed, per the units of time / rpm.

Torque will increase, assuming you don't lower the static compression ratio.

If you desire to increase the HP, then put on the larger blower later if you wish.

**

Simple rule of thumb regarding calculating torque.

-on gasoline-
NA Engines; Multiply CID by static compression ratio, and divide by ten.
FI Engines; multiply that value by your density ratio.

Here the compression ratio is 10.0;1
The last value is the density ratio.

(427 * 10 / 10)= 427 lbs ft.
(427 * 10 / 10 * 1.41) = 602 lbs ft.
(427 * 10 / 10 * 1.75) = 747 lbs ft.

-move compression ratio up to 12.0:1
(427 * 12 / 10 * 1.75) = 897 lbs ft.

Here we see the importance of the increases of both the
static compression ratio, multiplied by the density ratio.

Big motor, roots blower, makes 'Big Torque' numbers!

Again, this is a simple 'Rule of Thumb' equation.
Kind of get's you into the ball park, but not exact.

And as the density ratio and compression ratio increase, so does ones octane level..lol

Cheers

Mr rubber duck,

i have been waiting for you to chime in and I got it. So larger supercharger to make more hp because of the larger volume motor. As far as compression ratio goes, what should be my target say for a 427 and a kong 2650? That part I’m a little in the dark on.

 

Im curious how many in here have data on 427 LS engines with various size PD blowers?

 

following

 

Much easier to build big torque with the larger volume engine, then it is to make big horsepower with a larger volume engine.

I worked with several people 5 - 8 years ago with large volume engines, high compression, small blower and mild cams.

Big torque at lower engine RPM, didn’t matter about the horsepower to those people, as it’s just a bragging right.

11.0 to 11.25 Compression Ratio with them.
228* and 231* duration camshafts.
Bigger cam was tried, just idled rougher and more difficult to tune.
Best results 5600 to 5800 rpm.
850+ & 875 lbs ft torque.
Put a bigger blower on the 875 engine, and it went to 901...Big deal!

Very drivable and Engines were easy to tune.

Must use E85 with the high compression ratio.
If not, torque was down about 100 lbs ft, as a proper tune could not be used.

Also, little blower can’t fill the cylinders properly above approximately 5000 RPM.
LS 7 TB used.

Touch the throttle and the tires turned to grease.

Better heads a must!
If heads are too small, torque range / rpm span highly limited.

Cheers

 

Please see attached for head information. I only want to get 800whp. But if can make 850-875 easy, that’s what I want.

 

This is a good number to shoot for; easily within the range for those heads and that number keeps you away from the abyss that is the pursuit of the 'max effort' numbers.

 

Says the man who stepped into the abyss...

 

He knew what he was sayin'.

 

That's why you're getting the echo when I say it. It's deep in here,

Just in case anyone wonders what sort of collateral damage ensues when you select the "427" checkbox....
click my sig line.

 

That's why you're getting the echo when I say it. It's deep in here,

Just in case anyone wonders what sort of collateral damage ensues when you select the "427" checkbox....
click my sig line.

Yes, when you build the engine for 'Max / Peak HP' it can get very expensive..lol

 

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Are you saying that compression is to high?

 

^^^hahaha

 

So this chart is about right then.

 

Good Start; but the answer to your question is a bit more complex than that, as your engine has a roots blower on it. But let's start with; no you don't want 12.0:1 static compression in your engine..

Your HP & Torque goals will determine how much compression is required.

However, the Octane Level of your fuel, as well as the competence of the tuner will generally offer a resistance to how much compression one can really run.

This is especially so on the street, as heat becomes more of an issue than one normally sees on the drag strip, as runs down the track are only a few seconds long.

 

Who is building your engine?


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At this time i don’t know yet. I’m trying to get a better understanding of what to expect and to be pointed in the right direction

 

OP, may be more efficient to pay Matt / PatG or other reputable builder a consultation fee. They would set expectations based on verified build experience.

 

I think I’m going to go with the 376. I do want to be able to enjoy driving around town. As a matter of fact I hadn’t intended on going to the track with it.

 

Great info. I would like to build my own one day. And good luck bigwilly on the process.

 

10:1 bro.



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10.2..

Actually, it could be either.
We simply need to understand that anything around10.1, will generate
an efficient engine, capable of converting the mass charge brought into
the cylinder, into power, at a rate favorable for good torque and hp.

Up around 15.2:1 on NA Engines, we are looking for a %VE (not VE%) of over 128% when
the intake valve closes, when the piston has begun moving past the intake cycle, and is
moving into the compression cycle.

The trapped compression on these engines is ~17.2:1.

Actual VE% is above 150%.

So an engine spinning 10,500 rpm, is inhaling air as if it was spinning ~15,500 rpm.

This then provides for an NA Engine the ability to produce about 3-fwHP / CID.

And here, with these FI Engine platforms, it's a big thing to produce 900 HP
from 376 CID. That's 2.39 HP / CID, using a blower.

Why?

Because these engines, including the roots blower, are very inefficient.

Raising the Static Compression Ratio will help, but we desire to do
that without moving the engine into self-detonation.

This then depends on the customer / owner making rational decisions. . . .

Cheers

 

9.2 for me

 

And your engine will be spun to a higher RPM.

Therefore, along with a higher engine rpm and the resultant increase in piston speed, along with your larger blower, your engine will have a higher trapped compression ratio.

To increase either peak torque, or peak horsepower, within a given engine volume, it gets real expensive.

Engine rpm needs to be increased, and the entire Induction system needs to be replaced with highly sophisticated and expensive parts.

Would you like to speak regarding that.😆

 

Its good to read all of this and makes more sense to me why my builder went with 10.5:1 on my 427. Although going turbo and not supercharger.

 

To be fair, I run 93 most of the time.



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Determining the correct fuel, is so much more important than most understand.

A simple change in combustion chamber, piston design, engine cooling etc. can make differences in what fuel will be the correct fuel, for any given Engine being pushed to its limits.

With these engines heat is particularly the enemy.

The mass flow recovery system on these engines is most important!

The two rear cylinders need much help regarding reducing heat.

 

thats why i have gone hardcore on the thermal coatings within the head and piston as its ment to stop hotspots accruing and stop the exhaust heat getting into the head and thus intake temps should be least affected i hope, was hoping to get mine done by end of this year to be able to see if all my efforts have paid off but we got flooded out last month went foot thru the house and lucky i had my car up on jack stands couple feet off the ground which saved it but its made things a bit slower

 

Thought on this short block number

 

Compression is too low and the Eagle crank and rods would not be my choice.

 

1. I will say that AMS Racing built my LSX and it appears they do great work (though mine isn’t on the road yet, nothing to do with AMS) and they will happily build the engine with ANY special components you prefer and of course the price adjusts as you make upgrades… but they are just charging the difference vs the K1 or Compstar or whatever was in the advertised build. I started with their advertised LSX 427 and then spec’d EVERY internal part my way including special ordered rods and pistons. In my case they had the block and the Brodix crank in stock.
2. The m311 heads are built for a 4” bore and work just fine on bigger bores, but some will say that they don’t really take “full advantage” of say a 4.125 hole.
Since you aren’t shooting for the moon, that’s fine.
3. The m311 heads are SIX-BOLT heads and it would make good sense to consider taking advantage of that when buying a block. The LSX 376 for example would provide six-bolt security. Or Dart, RHS, LSNext etc.

 

All good advice..

I would like to add to a comment of yours, if I may..

------------------------------------------------

You wrote:
"2. The m311 heads are built for a 4” bore and work just fine on bigger bores, but some will say that they don’t really take “full advantage” of say a 4.125 hole?

The M311 Heads come with a 2.165" Intake valve, and
therefore, cannot be used on a 4" Bore.

The smallest bore recommended is the 4.065" bore.
Both the LS3 and the LSA come with the 4.065" bore.

These heads come with a 273 CC Runner Volume.
They are then capable of easily reaching HP Levels of +850 fwHP.

This is again verified by the fact they flow about 350 cfm, at or around convergence lift, or. . .(2.165 * 0.25)= 0.541" of valve lift.

If we desire to make 850 fwHP, then we simply divide that by the value of 4,as 4-Cylinders fire in a 90° V8 every 90°.
Where 4 * 90= 360°.
***Actually, a 376 cid engine, is only a 188 cid engine, per revolution / rpm then.
***It takes 720°, or two full revolutions to fire all 8-Pistons.

So we would need to make (850 / 4 = 213 hp / cylinder.
Let's assume the engine is going to be efficient.

We can then multiply 213 * 1.5, and we can surmise that we
will require a cylinder head that flows 319 cfm, by convergence lift.
***an efficient engine requires a ratio of ~1.5 cfm, per each fwHP.

These heads flow 350 cfm at convergence lift. . .
And they flow 322 cfm at just 0.500" of lift.

That's a 'Ton' of air..

---------------------------------------------------------

Now, since those heads were meant for a 4.065" bore,
the issue Mr. Big might decide to look into would be,
if he might desire to have the combustion chamber
modified to fit the 4.125" bore.
***I believe these heads were flowed using a 4.125" flow plate. . .

-he should at least look at this-
But I would think not, as then he would have to make up the
difference in the volume removed from the combustion chamber,
by choosing a different piston, decking the block, surfacing the head, etc.

---------------------------------------------------------

Your scenario as I recall:

1000 fwHP goal. . .

Divided by 4 = 250 fwHP / cyld.
Heads must flow 375 cfm by convergence lift.

And 2.250" * 0.25= 0.5625" of valve lift.

Your heads come with a runner volume of about 295 cc, as I recall.
Along with the 2.250" valve, your engine is scaled for ~1000 fwHP.
Might also break 900 lbs feet of torque. . .Depends!

1000 fwHP / 427= 2.34 fwHP per cid.

850 fwHP is a 'Cake Walk' for your engine..
850 fwHP / 427= 1.99 fwHP per cid.

But to make 1000 fwHP. . .

Sorting out fuel versus tune, piston speed versus absolute
pressure ratio of the blower, versus mass flow recovery system
efficiency, will be where you find that extra 50 fwHP to 100 fwHP
you might want to find, after your first dyno pull..lol
***Your manual transmission also helps. . .

***All valve lift values are consider to be 'Net Lift' Values,
after all flex and geometric issues are removed.