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Discussion Starter · #1 ·
Ok, I'm finishing up the '69 Chevelle LSA swap and forgot to get a throttlebody. The blower is currently stock, no plans to do any mods to it until much later.

With the shortages of just about everything right now, what's a good TB? If this blower isn't enough to get me where I want, im not sure I'd do much to it, in turn swap it for something bigger. So I don't want a YUUUGGE TB that's way bigger than the snout.

Suggestions?
 

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Discussion Starter · #3 ·
I'm not against stock, how are they with response?

I was told you can tune (reduce lag/latency) better in the ECM but I'm a noob at that.
 

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2011 thunder grey coupe a6 recaros.
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You can go to the ls7 90 mm with no issues, have you tried tony mamo?
 

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Discussion Starter · #6 ·

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2011 thunder grey coupe a6 recaros.
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Tony at mamo motorsports
 

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Discussion Starter · #9 ·
So we are talking, "ported" but still stock 87mm? Is there any difference between sensitivity/lagginess (I just created that word) between OEM modified vs aftermarket?

My 08 2500hd Suburban with 6.0 has TREMENDOUSLY poor throttle response. It would make this car flat out DANGEROUS...
 

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You should gain throttle response ported vs not.

The stock geometry is so 80 y/o’s don’t drive through their garage door.

You can also adjust how much it opens vs pedal which is just electronic obviously. That’s probably the problem with the 08.
 

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If snout and blower are stock, why not use the stock tb?


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Stock engine should work fine with the stock TB.

Most likely can also find one cheap as others have moved
to a larger TB when modifying their engines.
 

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Discussion Starter · #12 ·
Stock engine should work fine with the stock TB.

Most likely can also find one cheap as others have moved
to a larger TB when modifying their engines.
Engine isn't stock just the blower. It's actually an aluminum 6.0 block, with all forged Manley 4" stroker kit, 11:1 static CR. BTR Stage 4 PDS cam.
 

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Engine isn't stock just the blower. It's actually an aluminum 6.0 block, with all forged Manley 4" stroker kit, 11:1 static CR. BTR Stage 4 PDS cam.
The TB Size for any engine will be determined by the
HP Requirements made by the owner of the car.

Engine CID, Engine RPM, will ultimately determine the
'Required' size of any orifice within the induction system.

So if your going to shift that engine having an 4" stroke
at about 6800 rpm, it is going to require a larger TB
than if the engine had a 3.622" stroke at the same
engine rpm, as the Piston CFM Demand will be higher
at any engine rpm with the 4" stroke.

But with these engines the blower is going to put a 'Cap'
on any engine having a Piston CFM 'Demand' exceeding
about 1150 cfm, as that's about what a Stock 1.9L Blower
will 'Supply'.

Ported blowers will supply around 1250 cfm. . . Depending!

That's worth about 60 fwHP, maybe another 10 - 15 fwHP
depending on who ports and tunes.

-with the stock blower-
With your compression ratio I would stay with the 87mm TB,
maybe a 90mm TB, and move over to E85.

That is going to solve two issues.
First, the Octane Level will be increased.
Albeit mainly just the RON, but it still helps for short bursts.

Second, E85 is an Oxygenated Fuel and will deliver oxygen
to the cylinder, around the TB, as it is moved into the cylinder
via the fuel pumps / injectors.

If you go with a ported blower, and your engine rpm is
sufficient to generate a Piston CFM Demand to require
more air than the smaller TB's will deliver, then you
can move up to the 102mm TB.

So, it all comes down to your HP Demands, as well
as sufficient Piston CFM Demand. Your job is to
define the above and then fit the engine accordingly..:)

Now, let's end this by restating . . .
"Engine CID, Engine RPM, will ultimately determine the
'Required' size of any orifice within the induction system."

None of the above can be determined without understanding
if the cylinder head flow and camshaft are sufficient for your
intended 'Peak HP' engine rpm. .;)

Cheers
 

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Discussion Starter · #14 ·
The TB Size for any engine will be determined by the
HP Requirements made by the owner of the car.

Engine CID, Engine RPM, will ultimately determine the
'Required' size of any orifice within the induction system.

So if your going to shift that engine having an 4" stroke
at about 6800 rpm, it is going to require a larger TB
than if the engine had a 3.622" stroke at the same
engine rpm, as the Piston CFM Demand will be higher
at any engine rpm with the 4" stroke.

But with these engines the blower is going to put a 'Cap'
on any engine having a Piston CFM 'Demand' exceeding
about 1150 cfm, as that's about what a Stock 1.9L Blower
will 'Supply'.

Ported blowers will supply around 1250 cfm. . . Depending!

That's worth about 60 fwHP, maybe another 10 - 15 fwHP
depending on who ports and tunes.

-with the stock blower-
With your compression ratio I would stay with the 87mm TB,
maybe a 90mm TB, and move over to E85.

That is going to solve two issues.
First, the Octane Level will be increased.
Albeit mainly just the RON, but it still helps for short bursts.

Second, E85 is an Oxygenated Fuel and will deliver oxygen
to the cylinder, around the TB, as it is moved into the cylinder
via the fuel pumps / injectors.

If you go with a ported blower, and your engine rpm is
sufficient to generate a Piston CFM Demand to require
more air than the smaller TB's will deliver, then you
can move up to the 102mm TB.

So, it all comes down to your HP Demands, as well
as sufficient Piston CFM Demand. Your job is to
define the above and then fit the engine accordingly..:)

Now, let's end this by restating . . .
"Engine CID, Engine RPM, will ultimately determine the
'Required' size of any orifice within the induction system."

None of the above can be determined without understanding
if the cylinder head flow and camshaft are sufficient for your
intended 'Peak HP' engine rpm. .;)

Cheers
My intention is to run the motor primary on E-85 minimum. Pump gas only in emergencies. I plan to experiment with M1 hence the stainless tank and dual PWM 525's.

Was considering the Granatelli snout but I figured I would go bigger TB if/when instead of now. I'm no expert but I'm guessing a TB that's way too big for the current snout would only cause problems.

It's a 6 speed car so I can pick my shift points as needed, lol. 6800rpm would be plenty on stock L-76 heads anyways.

My wife's daily is a TVS2300 LS-7 so i COULD take her stock TB and upgrade her Z06 but then I'd have 2 cars needing tuned.
 

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My intention is to run the motor primary on E-85 minimum. Pump gas only in emergencies. I plan to experiment with M1 hence the stainless tank and dual PWM 525's.

Was considering the Granatelli snout but I figured I would go bigger TB if/when instead of now. I'm no expert but I'm guessing a TB that's way too big for the current snout would only cause problems.

It's a 6 speed car so I can pick my shift points as needed, lol. 6800rpm would be plenty on stock L-76 heads anyways.

My wife's daily is a TVS2300 LS-7 so i COULD take her stock TB and upgrade her Z06 but then I'd have 2 cars needing tuned.
Shifting at 6800 with a 4" Stroke will generate about 760 fwHP,
'If' the cylinder head flow is sufficient. When I say cylinder head
flow, I mean what will the cylinder heads flow 'With' the intake
manifold attached?

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

Displaying a normalized flow, one ends up with a chart showing
a percentage on the vertical axis. Here the chart also shows the
cylinder head flow on the horizontal axis.

If the cylinder head flow is insufficient, then the realized fwHP
will be lower. If the engine is Supercharged and the heads are
sufficient, then the fwHP realized will be more.

-how much should an engines cylinder flow-
If the cylinder has 12.95 Sq. Inches, as does an 376 LSA Engine, then
the flow potential for that cylinder would be equal to about 1892 cfm.

The above assumes a flow of 146 cfm per sq inch of flow area.
The cylinder heads for a V8 then would have to flow 473 cfm @28" of water drop.

Anything beyond that would require a compressor, and one
which is able to work in 'Compressible Flow'.

The above scenario would produce about 1268 fwHP.
So we all have a lot of work ahead of us to achieve that..lol'

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

Actually I tend to normalize the chart at 100 cfm per piston area.
And many engines won't make even that!

Here we would then see a bore having 12.95 Sq. Inch area
be able to inhale 100 cfm per Sq.".

This would result in 1295 cfm, and should produce about 868 fwHP.

All of the above calculations are made assuming the engine
is using gasoline having sufficient octane.

Cheers
 
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As a somewhat newer and very nfrequent poster on here (tend to search before asking anything) I find rubber duck’s info always interesting. Sometimes goes over my head but always love his valued and technical/smart approach, as I’m sure everyone else does. Definitely appreciate @Rubber Duck
 
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