...another... Throttle Body Thread

[go_a_way1]

Originally Posted by celek

I see all these throttle bodies and realize that the narrow runners are the problem.
Anyone else realize this as well?
I mean the 2017 manifold with larger diameter runners gains more with a stock throttle body.

^ that!! And op if you haven't you should port and polish (while your there) the exhaust side, that's probably your biggest restriction in flow right now

[nikitopo]

I'm getting sick of it. Everyone in this forum has an opinion, but in most cases without providing an evidence!

My opinion ...

In general throttle bodies work, but it also depends the manufacturer and the specifications. Additionally, they need an ECU tune to get the most of it. Here is a dyno of a stock car:




Another dyno with a bigger throttle body and a tune:



The torque curve is better and the engine feels strong even above the 7,200 rpm limit. It is known that the original intake manifold cannot provide sufficient air flow above this limit, but the bigger throttle body helps a lot.

[Lantana frs]

You can't compare tuned vs untuned.

[Spartarus]

For those who TLR, OP is using a Sprintex 335 supercharger. The big one. On a built engine.

Originally Posted by Irace86

Are you maxed out on pulley size? Meaning, couldn't you just buy a smaller pulley? Wouldn't that be the cheapest route?

The 335 hits a ceiling long before you max out the blower.

There's a point of diminishing returns with smaller pulleys that shouldn't be there.

Somewhere in the system there's a significant restriction.

The popular speculation points to the throttle body.

Other speculation points to the Laminova intercoooler core.

Originally Posted by celek

I see all these throttle bodies and realize that the narrow runners are the problem.
Anyone else realize this as well?
I mean the 2017 manifold with larger diameter runners gains more with a stock throttle body.

But he's on a Sprintex 335, it doesn't use the stock intake manifold. The Sprintex manifold has its own runners of different length and diameter than stock.

Originally Posted by Lantana frs

You can't compare tuned vs untuned.

Sure you can, you've just got to leave ignition timing alone. If you only correct the tuning to match AFR's between the 2 setups, that's exactly how you correctly compare.

I would try the Grams one from SpeedFactory if I were OP.

[Lantana frs]

Good points but when I see that a car has been tuned I have to wonder how much of the gain is attributable to the component being tested.

[Irace86]

Originally Posted by Spartarus

The 335 hits a ceiling long before you max out the blower.

There's a point of diminishing returns with smaller pulleys that shouldn't be there.

Somewhere in the system there's a significant restriction.

The popular speculation points to the throttle body.

Other speculation points to the Laminova intercoooler core.

I don't think the stock throttle body is a restriction unless he is pushing huge numbers. Do a google search for what people are making in terms of power and what type of numbers they are running at the drag strip or in competition, and you will likely find some pretty high hp cars running 65mm throttle bodies without issues. 2jzgte stock TB is 65mm ID, and Supras/cars with single turbo 2jz's are pushing huge numbers without aftermarket intake mani/TB combos.

Maybe the point of restriction is in the air flow path of the top mount blowers. Maybe that is why the Edelbrock, Harrop and Cosworth units put the manifold on top.

[Irace86]

Here is a video to explain if you don't know what I mean. Skip to 3:55.

[ame="https://www.youtube.com/watch?v=iT8texoWIvU"]https://www.youtube.com/watch?v=iT8texoWIvU[/ame]

[Kodename47]

Originally Posted by nikitopo

I'm getting sick of it. Everyone in this forum has an opinion, but in most cases without providing an evidence!

Probably because no one will fork out large amounts of money and then post up that it made no difference and not many people will pay to do something that they don't expect to work

If the OEM throttle body isn't a restriction then you can't flow more air without making additional changes. Without additional air you can't make additional power. Maybe a change in TB impacts the aiflow through the manifold enough to make a difference?

I would expect that the pull through SC cars will benefit from one, Cosworth have eluded that they are looking at one on their next setup above the smaller pulley. But until this point, they don't see one as necessary.

[Spartarus]

Originally Posted by Irace86

I don't think the stock throttle body is a restriction unless he is pushing huge numbers. Do a google search for what people are making in terms of power and what type of numbers they are running at the drag strip or in competition, and you will likely find some pretty high hp cars running 65mm throttle bodies without issues. 2jzgte stock TB is 65mm ID, and Supras/cars with single turbo 2jz's are pushing huge numbers without aftermarket intake mani/TB combos.

Maybe the point of restriction is in the air flow path of the top mount blowers. Maybe that is why the Edelbrock, Harrop and Cosworth units put the manifold on top.

Originally Posted by Irace86

Here is a video to explain if you don't know what I mean. Skip to 3:55.

I'll start by saying I was not arguing for or against the throttle body restriction, just explaining what he's looking for and why he was looking for it, to keep the thread on topic and stop speculation.

Also the Edelbrock, Harrop and Cosworth are roots blowers and they depend on the runner path to compress discharged air. They are just air pumps.

The Sprintex is a twin screw, it compresses the air internally. The discharge from a twin screw is already compressed. It blows down into a plenum, and the runners feed straight off of the plenum. That pair of 180 degree turns from the Edelbrock video does not exist in the Sprintex manifold. Regardless, twin screw superchargers are less sensitive to runner geometry. Also, we're not talking about low-end torque here. The 335 suffers from top-end problems, suggesting a restriction of some sort.

On to the comment about big numbers from small throttle bodies. The throttle body is only one of the possible restrictions in the 335 system, but it's not all that unlikely.

Let's look at those turbo 2J's... This is especially true on turbo cars. The difference here is the air passing through a stock throttle body in a turbo setup is already both compressed and intercooled. It's as dense as it's possibly going to get. You can fit a lot of it through a small opening.

In a suck-through supercharged setup, The air passing through the throttle body, through the intake elbow, and into the supercharger intake is not compressed. It's atmospheric. It is vastly less dense. You will need vastly more volumetric flow out of that same throttle body to move the same air mass as a comparable turbo setup.. Since the density is fixed at atmospheric, that means you need a bigger hole to suck through.

Originally Posted by Lantana frs

Good points but when I see that a car has been tuned I have to wonder how much of the gain is attributable to the component being tested.

Yes, and the problem with vendor tests is there's a huge incentive to make the charts ... "more optimistic."

[Irace86]

Originally Posted by Spartarus

I'll start by saying I was not arguing for or against the throttle body restriction, just explaining what he's looking for and why he was looking for it, to keep the thread on topic and stop speculation.

Also the Edelbrock, Harrop and Cosworth are roots blowers and they depend on the runner path to compress discharged air. They are just air pumps.

The Sprintex is a twin screw, it compresses the air internally. The discharge from a twin screw is already compressed. It blows down into a plenum, and the runners feed straight off of the plenum. That pair of 180 degree turns from the Edelbrock video does not exist in the Sprintex manifold. Regardless, twin screw superchargers are less sensitive to runner geometry. Also, we're not talking about low-end torque here. The 335 suffers from top-end problems, suggesting a restriction of some sort.

On to the comment about big numbers from small throttle bodies. The throttle body is only one of the possible restrictions in the 335 system, but it's not all that unlikely.

Let's look at those turbo 2J's... This is especially true on turbo cars. The difference here is the air passing through a stock throttle body in a turbo setup is already both compressed and intercooled. It's as dense as it's possibly going to get. You can fit a lot of it through a small opening.

In a suck-through supercharged setup, The air passing through the throttle body, through the intake elbow, and into the supercharger intake is not compressed. It's atmospheric. It is vastly less dense. You will need vastly more volumetric flow out of that same throttle body to move the same air mass as a comparable turbo setup.. Since the density is fixed at atmospheric, that means you need a bigger hole to suck through.

Everything you pointed out sounds reasonable. You make some good points that I don't have any objections to, except I should have clarified more about the
Edelbrock video. I wasn't using it to point out the long runners or low end torque benefits like they were; I was thinking about more about possible back pressure at high rpms from having tight turns, but as you point out, there are no 180 degree turns on this kit.

After looking at the manifold, the cooler does look restrictive. Am I mistaken in that it appears to only have three slots for air to pass through?



It could be the throttle body, and increasing it could help, assuming the supercharger doesn't have the same size intake ID where the TB attaches, right? Wouldn't it need to be just as large as any aftermarket TB, or need to get bored out to the same size?

[Calum]

Originally Posted by Irace86

Everything you pointed out sounds reasonable. You make some good points that I don't have any objections to, except I should have clarified more about the
Edelbrock video. I wasn't using it to point out the long runners or low end torque benefits like they were; I was thinking about more about possible back pressure at high rpms from having tight turns, but as you point out, there are no 180 degree turns on this kit.

After looking at the manifold, the cooler does look restrictive. Am I mistaken in that it appears to only have three slots for air to pass through?



It could be the throttle body, and increasing it could help, assuming the supercharger doesn't have the same size intake ID where the TB attaches, right? Wouldn't it need to be just as large as any aftermarket TB, or need to get bored out to the same size?

I see four slots in that picture, they look like they are angled to carry air from the middle of the two rotors in the compressor toward the outside and the runners.

Yes, the intake beyond the TB has to be large enough. The throttle plate and shaft take up some room and cause some restriction, so a case could be made to say that the the intake could be slightly smaller, but I'd want to see the testing before I agreed with the opinion.

That the air is already compressed before it enters the inter cooler section adds some credibility to the theory that the throttle body is the first restriction that should be removed. But again, data vs bench racing... Those in OP's position need more of one and less of the other.

I'll admit, I didn't originally read the OP full. I didn't realize he was running the 335 and a smaller pulley. That is a reasonable case for looking at the throttle body as a restriction. I keep coming back to the idea that the Sprintex intercooler/manifold was designed for a much smaller compressor. If Laminova published their air flow charts, it would be much easier to calculate the air flow through that intercooler.

[Spartarus]

Originally Posted by Irace86

Everything you pointed out sounds reasonable. You make some good points that I don't have any objections to, except I should have clarified more about the
Edelbrock video. I wasn't using it to point out the long runners or low end torque benefits like they were; I was thinking about more about possible back pressure at high rpms from having tight turns, but as you point out, there are no 180 degree turns on this kit.

After looking at the manifold, the cooler does look restrictive. Am I mistaken in that it appears to only have three slots for air to pass through?



It could be the throttle body, and increasing it could help, assuming the supercharger doesn't have the same size intake ID where the TB attaches, right? Wouldn't it need to be just as large as any aftermarket TB, or need to get bored out to the same size?

Thanks.

To answer, the ID of the throttle body is the narrowest part of the intake. Both the intake tube, elbow, and TB flange are wider than the ID of the throttle body. There is room for expansion.

There are 4 slots in the laminova core. It is speculated that it is quite restrictive. That said, since the SC itself is an internal compression unit, any downstream restriction would be measurable as a drop in manifold pressure. As the MAP sensor is downstream of the intercooler core and the boost pressure remains high, it's doubtful that the intercooler is the culprit.

[Hawk77FT]

Is there any point in going with the grams 72 mm tb while the intake manifold diameter is only 65mm? Boring it out too much might affect the gasket groove (the old plastic manifold)
The other option is to get the 2017 intake manifold and bore it out to larger ID to match or be closer to the larger TB. I wonder though what sort of benefits i should expect for doing so?!!!

[Spartarus]

Originally Posted by Hawk77FT

Is there any point in going with the grams 72 mm tb while the intake manifold diameter is only 65mm? Boring it out too much might affect the gasket groove (the old plastic manifold)
The other option is to get the 2017 intake manifold and bore it out to larger ID to match or be closer to the larger TB. I wonder though what sort of benefits i should expect for doing so?!!!

He's not using the factory intake manifold.

His throttle body is feeding the intake elbow of the Sprintex 335 Supercharger.