3.3t manifold research

[7thSonEngineering]

That's interesting. Tork's video claimed that a quarter (just under 1", or 24mm) wouldn't pass through the manifold, but from his video that might be at a point slightly closer to the turbo housing than at the bend where you measured (picture below is where he points when he mentions this). He does also mention a 1.1-1.2" opening, which would be 28-30mm, but even that should let a quarter pass.

View attachment 89111

In your picture, is the small circle at the bottom right the exit from the manifold into the housing? Or is that just the wastegate port?

View attachment 89112

Doesn’t neck down until after the wastegate opening and at that point is “ar.”

 

[Talloneus Khan]

Almost need to start a go fund me on this forum for a custom manifold that can attach to the stock hot side of our turbos.

That way it can be used on both stock, and hybrid turbos.

I imagine the lions share of the cost is making the toolings for the part, once a design is found to work

Makes me understand why people just jump right to custom big turbos. Its more expensive, but bypasses the problem that is to expensive for shops to invest in solving

 

[Thomby]

Doesn’t neck down until after the wastegate opening and at that point is “ar.”

I don't follow that last part...can you elaborate?

a custom manifold that can attach to the stock hot side of our turbos.

That way it can be used on both stock, and hybrid turbos.

A whole replacement manifold+housing is a much more complex part, and if you're going to the trouble of replacing that you're almost certainly going big turbo.

If the bottleneck is in the header/tube portion of the manifold, then a simple modification like porting or making a cut and welding in larger diameter sheet metal could make hybrid/stuffed turbos (upgraded rotating assembly in stock housing) more appealing.

But if @Jizzymane is saying the bottleneck is in the compressor housing itself, that's a much higher precision part that probably won't be easy to modify.

 

[7thSonEngineering]

I don't follow that last part...can you elaborate?

What I’m saying is that the manifold is 32mm until the waste gate (the first opening you see in the pics) right after the wastegate opening the manifold begins to neck down into the actual turbo. At that point it’s the turbo AR. And it needs to neck down

The only gains we are see from porting the turbo is by opening the wastegate holes up as large as possible from (20mm x2 = 40mm ) to (26mm x 2 = 52mm) perhaps

 

[7thSonEngineering]

Almost need to start a go fund me on this forum for a custom manifold that can attach to the stock hot side of our turbos.

That way it can be used on both stock, and hybrid turbos.

I imagine the lions share of the cost is making the toolings for the part, once a design is found to work

Makes me understand why people just jump right to custom big turbos. Its more expensive, but bypasses the problem that is to expensive for shops to invest in solving

That would be very expensive and then to purchase hybrid turbos on top of that. It would cost 5k-7k to replace both turbos

If somehow external wastegates could be made to work on our turbos I could see that freeing up an extra 100hp (stock turbos) 200hp (hybrids)

I will investigate this and the placement. The manifold is easily weldable but would the ECU go crazy ¿¿

 

[Thomby]

What I’m saying is that the manifold is 32mm until the waste gate (the first opening you see in the pics) right after the wastegate opening the manifold begins to neck down into the actual turbo. At that point it’s the turbo AR. And it needs to neck down

The only gains we are see from porting the turbo is by opening the wastegate holes up as large as possible from (20mm x2 = 40mm ) to (26mm x 2 = 52mm) perhaps

Gotcha. If there's no obvious bottleneck point, it sounds like the housing itself is the limiting factor. But maybe some minor porting, plus opening the wastegate port, and doing stuffed turbos may be worthwhile...I wonder how the 5-6000rpm portion of the dyno would look.

Don't know if you have access to a mill, but I wonder if a step drill in a drill press would work to enlarge the wastegate port uniformly a bit at a time (to make sure it still seals). Probably easier than a die grinder or dremel.

Going from 20mm to 26mm doesn't sound like much but it's a 70% increase in area/flow.

 

[7thSonEngineering]

Gotcha. If there's no obvious bottleneck point, it sounds like the housing itself is the limiting factor. But maybe some minor porting, plus opening the wastegate port, and doing stuffed turbos may be worthwhile...I wonder how the 5-6000rpm portion of the dyno would look.

Don't know if you have access to a mill, but I wonder if a step drill in a drill press would work to enlarge the wastegate port uniformly a bit at a time (to make sure it still seals). Probably easier than a die grinder or dremel.

Going from 20mm to 26mm doesn't sound like much but it's a 70% increase in area/flow.

Check my math 20mm circle = 10mm radius 26mm = 13mm radius


A= π x r(2)

A= 314.16mm

Ported

A= 530.93

530/314 =59% increase in opening area

Or

314/530 = 69% increase in opening area


I have a die grinder. Which the right head it wouldn’t touch the sealing face. The waste gate doesn’t seal directly over the waste gate hole it’s shifted over so a step bit may actually ruin the turbo because it can’t help but be centered. Tonight I may grind out the wastegate hole and upload photos

 

[Thomby]

Check my math 20mm circle = 10mm radius 26mm = 13mm radius

A= π x r(2)
A= 314.16mm
Ported
A= 530.93
59.1% increase in opening area

Agree til the last step: 531/314 = 1.69 or 70% increase.

Even simpler, you can skip pi since it cancels out and just compare % change in radius (or diameter). From 10 to 13mm (or 20 to 26mm) is 30% or 1.3x, so square it to get 1.69x.

 

[7thSonEngineering]

Agree til the last step: 531/314 = 1.69 or 70% increase.

Even simpler, you can skip pi since it cancels out and just compare % change in radius (or diameter). From 10 to 13mm (or 20 to 26mm) is 30% or 1.3x, so square it to get 1.69x.

Okay I appreciate the assist. Yea 26mm opening is 69% larger which gives us 138% increase in probable flow between the 2 waste gates

So it seems this mod is now “worth it”

 

[7thSonEngineering]

26-27mm from 20mm

 

[STINGER]

Can't believe i missed this thread. Good job for doing this, if results are fruitful ill be interested

 

[Thomby]

26-27mm from 20mm

That's the after? Or just marking where you intend to cut? Looks like it has pretty good margins to increase diameter.

Yea 26mm opening is 69% larger which gives us 138% increase in probable flow between the 2 waste gates

I don't follow the 138% flow increase, shouldn't it scale with area? Or is there some other rule of thumb?

 

[7thSonEngineering]

That's the after? Or just marking where you intend to cut? Looks like it has pretty good margins to increase diameter.


I don't follow the 138% flow increase, shouldn't it scale with area? Or is there some other rule of thumb?

The marks are where I intend to cut.


why do small increases in the radius of a circle cause large increases in the circles area??

Chat gpt answer
“
This occurs due to the quadratic relationship between a circle's radius and its area, which is governed by the formula A = πr².

Let's break this down step-by-step:

1. Mathematical Relationship
- Area = πr²
- This is a quadratic (squared) equation, not a linear one
- When r increases, the area increases by r²

2. Example Demonstration
- If radius goes from 1 to 2:
• At r=1, Area = π(1)² = π
• At r=2, Area = π(2)² = 4π
• The area increased by 4 times, not just 2 times

3. Why This Happens
- Each time radius increases by 1 unit, area increases quadratically
- Small changes in radius get "squared", causing larger area changes
- The effect becomes more pronounced with larger radii

4. Visual Representation
- Imagine drawing increasingly larger circles
- Small radius increases create exponentially larger "spread" of area

5. Practical Implication
- In design, engineering, or scientific calculations, even minor radius changes can dramatically affect total area or volume

This quadratic relationship is why small radius changes have such significant area impacts.”

 

[Thomby]

Right, area increases with the square of radius (or diameter), so a 30% wider circle will have (1.30^2) or 1.69x the area. But it should also have 70% more flow at the same velocity (or 70% lower velocity at the same flow).

Is the wastegate port a pretty uniform diameter from where it branches off the manifold to the wastegate itself, or is it more of a cone? A uniformly wider diameter should be the least restrictive, but I don't know how deep you'll be able to reach (or if there's enough spare material further down).

 

[7thSonEngineering]

Right, area increases with the square of radius (or diameter), so a 30% wider circle will have (1.30^2) or 1.69x the area. But it should also have 70% more flow at the same velocity (or 70% lower velocity at the same flow).

Is the wastegate port a pretty uniform diameter from where it branches off the manifold to the wastegate itself, or is it more of a cone? A uniformly wider diameter should be the least restrictive, but I don't know how deep you'll be able to reach (or if there's enough spare material further down).

It’s not deep at all. Pretty much right beyond the wastegate hole is the inside of the manifold. Barely a tunnel. 10mm max tunnel length. Look at the photos you can see the waste gate door.

 

[Thomby]

It’s not deep at all. Pretty much right beyond the wastegate hole is the inside of the manifold. Barely a tunnel. 10mm max tunnel length. Look at the photos you can see the waste gate door.

Ok this is great info. I've never ported a wastegate, and a quick search mostly returned people concerned over wastegate creep (opening too early) or trying to address overboost (which our cars don't seem to suffer from, outside some of the earlier cars in very cold weather).

Any chance you'd be able to dyno your car before the mods, to give an apples-to-apples comparison of the torque & power curves? And are you planning to swap them out yourself?

 

[7thSonEngineering]

Ok this is great info. I've never ported a wastegate, and a quick search mostly returned people concerned over wastegate creep (opening too early) or trying to address overboost (which our cars don't seem to suffer from, outside some of the earlier cars in very cold weather).

Any chance you'd be able to dyno your car before the mods, to give an apples-to-apples comparison of the torque & power curves? And are you planning to swap them out yourself?

Sure, It might be a while before I get the car on a dyno. My ex tuner wants to dyno it.

 

[BIG-D]

No rush mate... following with interest.

Might port my wastegate flapper holes myself and see if it still overboosts without my tunes

 

[7thSonEngineering]

No rush mate... following with interest.

Might port my wastegate flapper holes myself and see if it still overboosts without my tunes

Let us know I have an idea it’ll fix that and change your exhaust sound for the better + more top end. Butt dyno will tell you

 

[7thSonEngineering]

So great news. This (photo below) is ported out to 26mm (relatively circle).

Notice the unported flat surface I expect that if the wastegate flapper was modified to cover that portion it would be able to be ported out to 28mm. But that would require some custom machining and welding which I can do.