APS Inlet Pipe and JDM TGV Deletes Install

[mccorry]

You are not gonna get any appreciable difference in mileage with them, as much as I wish you would.

 

My install next month!!!!!!!

 

My thoughts exactly.....

[Infamous1]

My thoughts exactly.....

As I stated from my dealings this is after re-tuning for them as well. Im actually interested in LBGT's results, I can say on the stock turbo they were a complete waste IMHO.

[praedet]

All I can say is, same tires, same car, same road, same speed, and I went both uphill/downwind, and downhill/upwind. The only change was the APS Inlet and TGV deletes. Whether you all believe me, or not, oh well

 

The deletes remove a block to the flow, whether it is large or small volumes of air. It could be that the lack of tumbling reduces some pressure losses even at low rpms and throttle conditions...

 

Again, this is the results I have. That is all I can tell you

[LittleBlueGT]

As I stated from my dealings this is after re-tuning for them as well. Im actually interested in LBGT's results, I can say on the stock turbo they were a complete waste IMHO.

 

Any restriction that is elimintaed will help, the thing is on the stock turbo it appears it is mostly useless. I think technically all things being equal it wil give a gain, nut maybe only 2 or 3 whp.

 

The other thing of note is that any restriction like TGV will be let's say X amount of restriction at VF40 flow levels, but at 1.5 those flow levels it will be more then 1.5 the restriction. It would not be a linear relationship.

 

I wouldn't be surprised if at 450whp levels it is a 20whp restriction.

 

When I am done I will do my best to show graphs showing the difference. I think I have a big enough colection of logs that I will be able to match atm press and temp.

[LittleBlueGT]

All I can say is, same tires, same car, same road, same speed, and I went both uphill/downwind, and downhill/upwind. The only change was the APS Inlet and TGV deletes. Whether you all believe me, or not, oh well

 

The deletes remove a block to the flow, whether it is large or small volumes of air. It could be that the lack of tumbling reduces some pressure losses even at low rpms and throttle conditions...

 

Again, this is the results I have. That is all I can tell you

 

You do realize at low loads there is a huge restriction before the TGVs?

 

THE THROTTLE that is mostly closed.

 

I think even you have to admit that a difference of a few mpg is not there.

[praedet]

You do realize at low loads there is a huge restriction before the TGVs?

 

THE THROTTLE that is mostly closed.

 

I think even you have to admit that a difference of a few mpg is not there.

I promise I am giving you my Data, you all don't have to be mean to me

 

Here is the deal, 2 planes create more air disturbances than a single. 2 Cars, same thing...

 

The throttle is mostly closed, so as air comes through, it tumbles through that. But, the intake manifold gives it a lot of smooth pipe with easy bends to staighten out again. Then right before it gets sent into the engine, the TGVs' rod and large plate WILL create a turbulent wake in the midst of relatively smooth laminar flow. This DOES make the pressure drop. Even on a wind tunnel running at about 10 ft/s we can see pressure drops for the whole wind tunnel by putting in models that litteraly only block 5% of the cross-sectional area.

 

Am I 100% convinced, no. Do I have some data that shows something has changed, yes...

[Guest]

There is also possibility of freak gas. On a recent trip (with the new wagon I bought) I got 24 mph driving at 85-90 mph. That's crazy because the same car was getting that much driving 70-75 at best.

[LittleBlueGT]

I promise I am giving you my Data, you all don't have to be mean to me

 

Here is the deal, 2 planes create more air disturbances than a single. 2 Cars, same thing...

 

The throttle is mostly closed, so as air comes through, it tumbles through that. But, the intake manifold gives it a lot of smooth pipe with easy bends to staighten out again. Then right before it gets sent into the engine, the TGVs' rod and large plate WILL create a turbulent wake in the midst of relatively smooth laminar flow. This DOES make the pressure drop. Even on a wind tunnel running at about 10 ft/s we can see pressure drops for the whole wind tunnel by putting in models that litteraly only block 5% of the cross-sectional area.

 

Am I 100% convinced, no. Do I have some data that shows something has changed, yes...

 

 

I agree with you bro, trust me, I bought em too.

 

3 mpg ain't for real though, maybe you saw it once, but even 1 mpg on average would be hard to swallow.

[Infamous1]

All I can say is, same tires, same car, same road, same speed, and I went both uphill/downwind, and downhill/upwind. The only change was the APS Inlet and TGV deletes. Whether you all believe me, or not, oh well

Any changes to the tune?

[praedet]

The funny thing with this, is that I actually don't have to justify these to myself as I am getting a larger turbo where the benfit will show I just thought it was interesting that since installing these, my mpg has gone up.

 

Oh well, next time I will keep the data to myself

Any changes to the tune?

Still tracking down issues w/ the Prodrive BCS

[LittleBlueGT]

next time I will keep the data to myself

 

I have found this last few months the only way I can be taken seriously is if any performance mod I do I report with extreme statistical accuracy, or bring down any possible expectations I may have and report with brutal pessimistic honesty.

[BlackHole]

Well, I for one appreciate the data you both put out. But I understand your feelings - I got tired of the same behavior when I was heavily modding DSMs and publishing data.

[mccorry]

For the record... I wasn't trying to be mean... I just can't understand how removing the TGV plates from the intake runner improves gas mileage.

 

The throttle plate is the main restriction and the TGV's would only help to atomize the incoming fuel / air charge.

[Infamous1]

I also was providing my data based on both setups being fine tuned. If I weren't upgrading my turbo down the line I would be pissed!!!

[jomamma]

For the record... I wasn't trying to be mean... I just can't understand how removing the TGV plates from the intake runner improves gas mileage.

 

The throttle plate is the main restriction and the TGV's would only help to atomize the incoming fuel / air charge.

just my opinion. but look at the comparison, deleted and non-deleted. if you apply the same percentage of throttle to both, the deletes will move more air. the cfm to fuel flow, if you will, will improve

http://images.turbomagazine.com/images/0702_turp_15z+project_subaru_sti+compressor_housing.jpg

[mccorry]

Negative.....

 

1.) While cruising, air flow is determined by the throttle plate... not the TGV's.

2.) The TGV's in your picture aren't even fully opened.... so it is misleading.

3.) Even if the TGV's allowed more air flow while cruising (which they don't), the ECU will work to maintain AFR where it needs to be... so more air = more fuel. Period.

[praedet]

Steve,

Whether they do accomplish something or not, my contention is not MORE airflow, but a different type. An obstruction in the flow creates a pressure loss and requires more energy out of the flow to sustain a nominal velocity. That is the effect that I think could be in play.

 

Think of it this way, at low velocities frictional drivetrain losses are by far the largest part of the drag on a car. But, if you clean up the Aero on the car you will still see a reduction in drag.

 

For that matter, why would Stg 2 see better gas mileage in cruise if the throttle-plate being mostly closed is all that matters. Stg 2 changes are down-stream of the engine anyway...

[jomamma]

Negative.....

 

1.) While cruising, air flow is determined by the throttle plate... not the TGV's.

2.) The TGV's in your picture aren't even fully opened.... so it is misleading.

3.) Even if the TGV's allowed more air flow while cruising (which they don't), the ECU will work to maintain AFR where it needs to be... so more air = more fuel. Period.

you're not following my point. if you compare cfm on tgv to non-tgv at the same throttle position, the deleted will allow mofe cfm. take a straw and put a blockage in it. you're telling me it doesn't take more energy to blow more threw?

[mccorry]

Steve,

 

For that matter, why would Stg 2 see better gas mileage in cruise if the throttle-plate being mostly closed is all that matters. Stg 2 changes are down-stream of the engine anyway...

 

 

IMHO, Stg 2 runs better MPG than stock because our cars are tuned pig-rich from the factory. The Stg. 2 tunes lean out the AFR throughout the RPM/load range.

[mccorry]

you're not following my point. if you compare cfm on tgv to non-tgv at the same throttle position, the deleted will allow mofe cfm. take a straw and put a blockage in it. you're telling me it doesn't take more energy to blow more threw?

 

 

If you are passing 50 scfm through the throttle plate to maintain 50 MPH, let's say.... and the TGV's are full open (engine at operating temperature), then yes... you will have a differential pressure across the TGV assemblies. It will be VERY minor, however, in comparison to the delta-P across the throttle plate.

 

Now... if you take out the TGV assemblies alltogether then you reduce the pressure loss in the intake runner. This is true. However, the throttle plate is still the determining variable on air flow. The engine is only going to need xxx cfm to maintain the power necessary to maintain RPM/speed.

 

Or maybe I'm completely wrong.

 

Either way... I have no explanation for Ted's results. Something is going on here that I am missing... I'll admit.

[praedet]

If you are passing 50 scfm through the throttle plate to maintain 50 MPH, let's say.... and the TGV's are full open (engine at operating temperature), then yes... you will have a differential pressure across the TGV assemblies. It will be VERY minor, however, in comparison to the delta-P across the throttle plate.

 

Now... if you take out the TGV assemblies alltogether then you reduce the pressure loss in the intake runner. This is true. However, the throttle plate is still the determining variable on air flow. The engine is only going to need xxx cfm to maintain the power necessary to maintain RPM/speed.

 

Or maybe I'm completely wrong.

 

Either way... I have no explanation for Ted's results. Something is going on here that I am missing... I'll admit.

Steve,

I am at a loss also.

 

I do not believe I am getting extra flow at low throttle settings. I agree w/ you that the throttle determines that, and even if I were, the car would HAVE to adjust for it to balance fuel.

 

But, if the air has more total pressure as it enters the chamber, than combustion WILL be more complete and efficient. That is the only way I can explain it. The losses in total pressure as the air tumbled over the open TGVs would not be huge, but they would be there...

[mccorry]

Yes, Ted... but wouldn't the extra turbulance that the TGV housings provide (vs. an assmumed laminar flow w/ deletes) HELP to atomize the fuel being sprayed from the injector nozzle?

 

Better atomization = better powere and a more complete burn.... no?

[SBT]

Yes, Ted... but wouldn't the extra turbulance that the TGV housings provide (vs. an assmumed laminar flow w/ deletes) HELP to atomize the fuel being sprayed from the injector nozzle?

 

Better atomization = better powere and a more complete burn.... no?

 

At lower intake volumes/pressures I think that would be the case - which is why the TGV was created (for cleaner idle/off-idle burn). But at higher vols/press - believe this would be just the opposite. Higher pressures would enable more atomization - No?

SBT

[Infamous1]

Yes, Ted... but wouldn't the extra turbulance that the TGV housings provide (vs. an assmumed laminar flow w/ deletes) HELP to atomize the fuel being sprayed from the injector nozzle?

 

Better atomization = better powere and a more complete burn.... no?

This is my understanding too, that is why when porting them you want to leave a rough surface rather than a mirror polish.

[LittleBlueGT]

Here is my take.

 

One aspect of engine efficiency is the amount of work the engine has to do to INGEST the air.

 

The more restrictions, the more work is lost.

 

The TGVs will create more work for the engine to do while at partial throttle, but it is very minuscule.

 

I would imagine you freed up about 0.002 whp. So about .04 mpg improvement.