Unlocking the hidden power and flow of your OEM turbo

[Tuning Alliance]

Were these tests done on the dyno or on the road? The main reason I ask is more boost doesn't always equal more power with the vf40/46 but I know you already know that so my intent is not to be condescending in any way. I was curious if you had actual dyno graphs to show the increase in HP. The compressor itself is not very efficient at higher rpm and most tests have shown it doesn't actually create much more power at the expense of much higher IAT's at the tmic and throttle body.

 

I am in no way questioning the fact it makes more boost, just curious if you have tested to see that it did actually increase WHP in the higher rpms where you are seeing higher boost levels on repeated pulls *ie more than just one pull to see repeated results*. I remember testing the vf40/vf46 with an external wastegate about 4 years ago and we saw no increase in power from 15psi to 19psi at 5500rpms on * this was right before a turbo/intercooler upgrade so he didn't care about the life of the vf46 or the tmic blowing. We did see an increase in torque on the first pull and then it dropped on every pull following due to built up heat etc*

 

Dave

 

The tests were all done on the road, no dyno data was collected. I disagree and believe there are definite gains to be had by extracting more boost at higher rpm.

 

For example if you're making the same power at 19 psi as 15 psi (5500 rpm), you must be running significantly less timing. Something like 8-10 degrees less timing. Another way to think about it is regardless of temperature if you have more boost, than you have more cylinder pressure, thus more torque.

 

To back this data up I posted the MAF voltage, as you can see it is drawing in significantly more air from ~3000rpm and up. More air flow, more pressure, more power! I was concerned pushing the turbo harder would create excess heat and potentially create tuning issues. However, I had no issues, was not battling knock and ran only slightly less timing at the elevated boost level ( about 0.7 degrees less at 5500 rpm)

 

 

The main thing that jumps out to me is you saw a very low wgdc to hit target and then a 30% increase in wgdc to hold about 2-3psi more *from 4500-redline* and basically maxed *or 81% at least* the wgdc even with the new actuator. To do that shows the turbo is most likely out of its efficiency range and is wanting to mechanically taper.

 

Dave

 

I'm glad you brought that up, because this is a common misconception. As I mentioned we were unable to fully preload the waste gate. People tend to think the drop in boost is the turbo not able to physically flow that amount. Where much of the boost curve is controlled by the flow rate of the waste gate port. The spring pressure alone simple controls when the flapper will open, however as you add spring pressure the flapper opening is less at a given pressure. So the goal is to have the flapper open less up top, directing that energy back into the turbine to drive more boost.

[snm95ls]

If anyone had data on turbine drive pressures, it would be relatively easy to see just how much spring pre-load you would need to keep the WG from opening up top.

 

Sadly, very few people ever implement the equipment to log this.

 

I'm guessing at least 2:1 ratio of turbine drive to intake pressure on such a restrictive turbine.

 

You know...I do have an Innovate SSI-4 laying around somewhere. just need a couple of pressure transducers and a bung in the UP.

 

hmmm.

[cryo]

thanks for chiming in with your input. I'm glad you didn't take it negatively as I was really just asking for your point of view as all of us experience different things when testing in different situations and enviroments. I have actually seen exactly opposite in terms of testing directly based off maf voltage a few different times and that's why I never consider it a good measurement of overall flow when things get close to being complete. I have done back to back runs on the dyno where we saw more voltage and actually saw less power. The fact that the measurement of airflow is happening prior to the turbo does not always mean the air density entering the engine is actually "worth" more if its super heated from the turbo itself.

 

Compression creates heat thus makes everything in the system work harder to compensate. Running the turbo at 19psi was kind of a joke to see and it did what we expected. It made the same amount of power and since load did not increase and timing needed to be reduced to keep detonation at bay after the second run during my test we saw about the same amount of power but a LOT more stress on the components. Had we been testing post intercooler temps I know it would have been clear as day we were pumping a ton of hot air. Since we do not have compressor graphs we cannot see true efficiency so the only way to know is test on the dyno.

 

True timing and boost do effect each other and normally you would see less timing with more boost but my goal is to run the lowest boost and timing to create the most overall power safely over a 3-5 run test. I like to test more boost with less timing and more timing with less boost but given the turbo trim and such its normally pretty easy to know where you are going to end up given the fuel. Most times I end up at lower timing and more boost as its easier to make power with boost but if we push the turbo farther than its happy we can actually cause the need for less timing and more boost to keep detonation at bay which is on the other side of where we want to be. In these situations I have found that I can make the same amount of power by running timing that compensates for the turbo's lack of efficiency so I try and work with that.

 

The boost falling off is a little more complicated than a weak wastegate actuator. This has to do with a lot of things including EGBP,turbine size,engine size etc but if I see a wastegate shooting for the stars at the top end it normally shows its trying to make boost and the turbo itself is incapable of it. The VF40/46 is designed for low and midrage grunt at the expense of top end. Its downfall is having a very small turbine for a 2.5L engine. Some people say a 7-7.5mm exhaust housing should never be used on anything larger than a 2.0 due to it choking the motor but it provides great torque and early spool. You see a lot of oe manufactures taking this route as they care more about drivability in the sub 4500rpm range more than top end for the majority of factory turbocharged cars these days. If I only see a 1psi boost increase for 10% wgdc I normally start to look at why. If you don't open the wastegate at all it will hit 25psi but the question then is was it efficient to anywhere near that level and simply blocking the wastegate closed did infact increase boost so we forced a turbo to create much more boost than was efficient

 

I suppose the thing to realize is that we are only talking a psi or two which may or may not be creating enough heat to cause an issue vs the airflow/air density available from that 1-2psi. I will say that my data has shown it to be of little gain from the changes but I'm very happy to see someone else doing the tests as well to see if there are gains to be made. I just really wish we could see repeatable dyno data to see if its a good investment on the stock turbo

 

Again thanks for your response, insight and sharing with the forum. I hope you decide to take it to the next step and do some dyno testing and post the results as well like you did on the grimmspeed intake.

 

Thanks

 

Dave

[Tuning Alliance]

I understand what your getting at, but I just don't really agree. Yes, certainly high boost pressure creates more heat, due to physics. Also, yes I agree that pushing a VF40 beyond its limits will not yield a safe and reliability.

 

However, I have run plenty of VF40/46 at 19-20 psi peak with no issues. If I can run 19 psi at 3500 rpm, I don't think asking for 15 psi at redline is over spinning the turbo. Looking at a compressor map is helpful however you really do not know where you are on the map unless you are in fact measuring the compressor wheel speed.

 

Regarding MAF voltage and pressure data from the ECU. I believe this data is fairly accurate data and offers much insight into power production. If the MAF is reading high voltage (More flow), and the MAP is reading higher boost (more pressure in a given volume), than there must be more air in the engine. Can we agree on that? Sure it can be hotter but overall more air more power.

 

More air requires more fuel. Thus it can also be verified that injector duty is increased, or AFR is changed if duty is the same. The only thing remaining in question is timing.

 

If you have already collected this data have you shared it somewhere? Is timing and AFR data included?

[cryo]

Hey there,

 

I personally do not run the stock turbo up to 19ish psi for my own reasons but if you have found reasons to do that I'm sure they are something you feel is worthwhile for your customers.

 

I agree that turbine speed is needed to get the full story but any compressor map can be used to get in the ball park if ones provided to get an idea of true PR with an intended boost level. I love going through garretts book when choosing specific turbo's as maps are pretty helpful to know if you ever stand a chance to get into the ballpark to begin with but not so much to see 1-2psi gains etc which is why at that point the dyno must be used. I have gone to a couple different training seminars, gone through tons of literature and watched the difference in real time on the engine dyno about how different housings produce different output and curves and analyzed the changes on paper as well. That really opened my eyes to the fine details of turbo's efficiency and how running a turbo out of its efficiency range puts more stress on the turbo as well as internal components and you sometimes end up using more boost,more fuel and less timing to make the same overall power as you could of with less boost, less fuel and still keep timing very moderate.

 

Unfortunately I do not agree that more air in the cylinder is always better as it matters directly on charge temp as well. A denser intake charge inside the engine is better than a less dense charge as less usable molecules are available for combustion due to thermal expansion. So if your running 16.5psi as a low intake temp you will be able to cram more overall pressure into the intake event than 19psi of hot expanded air. When you are cranking up boost without any way to measure outlet temps and cramming in superheated air you are running the risk of having to reduce timing or add fuel to compensate for the extra heat.

 

If you are seeing AFR going leaner or IDC increasing without ANY changes to Injector scaling or maf scaling and specifically doing these tests with both 100% scaled to target than it would appear overall volumetric efficiency has increased BUT with a maf based car its always very hard to say as well without back to back to back pulls on the dyno to make sure that its not just observed during one run at the expense of the next while things are still very toasty. Most times there are other adjustments made that may throw off the calibration and something as simple as adding a little uphill event or wind to the log will show more load,maf and thus the impression of more power. Since maf scaling and injector scaling directly effect every table that has to do with load and IDC it can be a chase your tail situation without a controlled environment.

 

Unfortunately I do not have this data available to me anymore as it was 3-4 years ago and didn't really think it was data that would be important down the road but I should have known it may be helpful to keep it around for the future.

 

I feel as though I may have steered your thread in the wrong direction and that was NOT my intention and for that I apologize. I'm glad we are able to discuss this with respect and bounce opinions off each other without any animosity but I feel it may be in my best interests to allow this thread to continue without my opinions and such due to our different views on the situation.

 

It appears we just have a difference in opinion on some of these details based on our own personal experiences with customers but that's what makes this world great is we can all have different opinions and reasons for those opinions and it doesn't make it right or wrong. Perception is reality and its very hard to change perception when opinions differ without hard data in a controlled environment. Even then its still subjective.

 

 

Thanks a bunch for what you do for the forums, I'm glad to have others here that truly care about their customers enough to test these limits and see where they may gain rather than just try and make a buck.

 

Dave

[Tuning Alliance]

http://legacygt.com/forums/attachment.php?attachmentid=13191&stc=1&thumb=1&d=1319090762

http://www.not2fast.com/turbo/maps/ihi_maps.gif

 

They all do flow pretty well at 2.0 pressure ratio (14.7 psi) And as I mentioned I was targeting 15 at redline. Being above that you are generally in a higher band of efficiency for most IHI turbo, and all that all compressor maps. They tend to be shaped moving up and to the right. 19 psi (2.29PR) is not so bad as it looks like peak flow is near 2.4PR for most.

 

 

Lets also be fair at your altitude it is a different story. I would not want to run 19 psi up there. So I understand the different perspective on tuning. =)

[cryo]

Like I mentioned before, The compressor maps tell you what it flows to get you in the ballpark. Then infield testing to test it against the other components on the car determine if it makes increases. This is where you find the end all product.

 

My perspective on tuning is not based solely on altitude as I have tuned cars in quite a few states and elevations although I can say it helps extremely to have data from sea level to over a mile high for testing purposes. A lot of major auto manufactures come here to do broad spectrum testing as there are not many better places to test from 3500ft to 14000 to calibrate their cars.

 

At the end of the day we both share a passion for this and I know I am one to use what I have experienced in high regard as do you and that's very respectable. I would love to see dyno data on it but obviously you are not required to prove something to anyone if you have experienced the gains first hand and know it to be true based on your collected data.. I'm just a data guy by nature so I pour over it but it only does so much vs actually measuring torque at the wheels when it comes to 5-10 safe hp increase. So at this point I will step out of the conversation respectfully as I feel I have overstepped and turned this testing and data process thread into a speculation thread and am never here to stop informative growth in the community

 

Thanks for the space

 

Dave

[Tuning Alliance]

I'd love to see your data if you want to send it over. tuningalliance@gmail.com

 

If anyone wants to set up and be a dyno test mule let me know.

Again requiring a VF40/46 and a tmic.

 

I'll do 50% a dyno tune for a willing participant.

[Tuning Alliance]

Look at that low solenoid duty! Like you said, more room to go... With the right bracket, the new actuator will have enough room for a full range of adjustment. We'll bring both cars back so you can tune the GF's Saabaru, and put together a bracket for the 46, if you'd like to.

 

The car drives wonderfully, Mike. Thanks again. Not bad for a 175,000 mile VF-46 and motor

 

We might need to get you on a dyno... Did more boost feel faster to you?

[solidxsnake]

Get in touch if you need a test-mule, Mike! I imagine since you've already gotten my car on a solid tune, doing these back-to-back tests would be really quick for you to setup and gather data for. I imagine the results you'd get would still be worthwhile, even though I have the JmP VF46.

[Tuning Alliance]

Get in touch if you need a test-mule, Mike! I imagine since you've already gotten my car on a solid tune, doing these back-to-back tests would be really quick for you to setup and gather data for. I imagine the results you'd get would still be worthwhile, even though I have the JmP VF46.

 

Want to come to esp on sat?

 

Crap I need to order the actuator.

[LatentWagen]

We might need to get you on a dyno... Did more boost feel faster to you?

 

Yes, the car was definitely faster while holding more boost... not sure why this is even a question at these PRs.

 

The proof is that the car responded well to the additional 1.5-2lbs through the mid-range and top-end. Were IATs likely a few degrees hotter? Of course, because more boost. Was that additional heat in the charge enough to negate the added boost? Not from what I felt through "old reliable" aka my butt dyno

 

Seriously though, Mike said he didn't have to back off much to accommodate for the extra boost, and we did repeat pulls on the road. The car was consistently faster. I'd be all for a dyno session to put it down on paper.

[Tuning Alliance]

Yes, the car was definitely faster while holding more boost... not sure why this is even a question at these PRs.

 

The proof is that the car responded well to the additional 1.5-2lbs through the mid-range and top-end. Were IATs likely a few degrees hotter? Of course, because more boost. Was that additional heat in the charge enough to negate the added boost? Not from what I felt through "old reliable" aka my butt dyno

 

Seriously though, Mike said he didn't have to back off much to accommodate for the extra boost, and we did repeat pulls on the road. The car was consistently faster. I'd be all for a dyno session to put it down on paper.

 

Thanks! The additional heat would have to be some much that knock detection would occur, large amounts of timing would be pulled, and than it might make less. It did not pull any timing all day during these pulls.

[08Legacy-GT]

I'd love to see your data if you want to send it over. tuningalliance@gmail.com

 

If anyone wants to set up and be a dyno test mule let me know.

Again requiring a VF40/46 and a tmic.

 

I'll do 50% a dyno tune for a willing participant.

 

Second... Please provide some data.

 

 

I do find it funny you said bout 4 times in your initial post dont take this the wrong way haha. Whenever someone starts out saying that, its entirely true to be taken that way.

[Tuning Alliance]

Second... Please provide some data.

 

 

I do find it funny you said bout 4 times in your initial post dont take this the wrong way haha. Whenever someone starts out saying that, its entirely true to be taken that way.

 

:lol:

 

It was like how you start off a break up conversation with your significant other. It's okay Dave is a good guy!

[cryo]

:lol:

 

It was like how you start off a break up conversation with your significant other. It's okay Dave is a good guy!

 

Yeah I guess I'm always very sensitive when stepping into another tuners thread providing opinions as so many take it to heart as an attack rather than to better the community and share opinions and experiences. Arguing and never being willing to take new testing into account is what makes progress stop and I'm not about that at all.

 

Unfortunately like I said I tested this theory back about 3-4 years ago and found what I felt were conclusive results for where I felt safe. I am excited to see your results and am always willing to eat humble pie if it betters the community and there are significant gains to be had safety and consitently.

 

I appreciate the kind words and have nothing but respect for anyone in this field and expecially the ones like you on this site.

 

Thanks

 

Dave

[08Legacy-GT]

Yeah I guess I'm always very sensitive when stepping into another tuners thread providing opinions as so many take it to heart as an attack rather than to better the community and share opinions and experiences. Arguing and never being willing to take new testing into account is what makes progress stop and I'm not about that at all.

 

Unfortunately like I said I tested this theory back about 3-4 years ago and found what I felt were conclusive results for where I felt safe. I am excited to see your results and am always willing to eat humble pie if it betters the community and there are significant gains to be had safety and consitently.

 

I appreciate the kind words and have nothing but respect for anyone in this field and expecially the ones like you on this site.

 

Thanks

 

Dave

 

 

What was your testing process? Can't ask others to post their data, but you wont yours? I wont show you mine, if you show yours?

[Flinkly]

What was your testing process? Can't ask others to post their data, but you wont yours? I wont show you mine, if you show yours?

 

he's (Dave/Cryo) already stated that he no longer has the data, as it was from some time ago and didn't think it was useful to keep in a "this didn't work" folder.

 

And if Mike/TA isn't gonna get snippy with Dave/Cryo, i don't think anyone else has any ground to stand on to do it instead.

 

Do you have some data to share? or anything constructive to add?

 

 

K, lets get back to the task at hand now...

[Tuning Alliance]

he's (Dave/Cryo) already stated that he no longer has the data, as it was from some time ago and didn't think it was useful to keep in a "this didn't work" folder (i can imagine he'd have QUITE a large folder of "junk" data, and unless he spent alot of time organizing, would take a little time to find anyways).

 

And if Mike/TA isn't gonna get snippy with Dave/Cryo, i don't think anyone else has any ground to stand on to do it instead.

 

Do you have some data to share? or anything constructive to add?

 

 

K, lets get back to the task at hand now...

 

So I have to prove more boost equals more power? I figured this was a pretty well know assumption.

 

Here is a quick example. Now mind you this is not a VF40 map, but the 52 and 40 have a very similar design, trim, etc.

http://i463.photobucket.com/albums/qq357/tuningalliance/IHI%20comp%20map%20Compare.jpg

You may note the four dots I placed on the compressor map all in the same vertical axis (same flow rates). You may also notice the efficiency bands (hard to read the values). When asking near maximum flow rate from a given compressor, it is in fact much more efficient.

Red 1.6 PR (8.8psi) Appears to be on the 55% efficiency line.

Cyan 1.8 PR (11.7psi) Appears to be on the 60% efficiency line.

Green 2.0 PR (14.7 psi) Appears to be on the 65% efficiency line.

Blue 2.2 PR (17.7) Appears to be on the 70% efficiency line.

 

Nearly every compressor map is similar to this.

 

http://3.bp.blogspot.com/_eYNXA0gKwI0/TVHE5kZ_AEI/AAAAAAAAAR8/eCTl53qzFdY/s1600/Garrett+GT22+Turbocharger+GT2259+Compressor+Map+52+Trim+280+HP+Honeywell+450x600+www.TurbochargerSpecs.Blogspot.com.jpg

 

If you were to draw a vertical line at 25 lb-min flow.

at PR 2 (14.7 psi) you are 70% efficient. However at 2.5 PR (22.1 psi) you are now 75% efficent. I choose this map because its a small wheel, similar to the VF40 compressor.

[Flinkly]

oh, you've got nothing to prove to me Mike/TA. I'm just here to follow the original discussion of upgraded actuators on stock turbos.

[Tuning Alliance]

If you guys want to learn more about how boost pressure influences power output and charge temps, I suggest you play with Borg Warners Match Bot online tool.

 

http://i463.photobucket.com/albums/qq357/tuningalliance/matchbot%20data_2.png

 

As you can see, I have compared a variety of boost pressures all at the same rpm and conditions. I have even input accurate compressor efficiency data which indicates reducing as pressure rises (15psi is 66% eff. & 20 psi is 62% eff.) Turbo outlet temps range from 265f to 324f, and post intercooler temps range from 94f to 100f) So yes it is hotter with more boost.

 

Yet power calculations don't lie.

15 psi = 329 hp

16 psi = 339 hp

17 psi = 349 hp

18 psi = 359 hp

19 psi = 370 hp

20 psi = 380 hp

 

http://i463.photobucket.com/albums/qq357/tuningalliance/power%20backup%20comp.png

[cryo]

Independent testing from one shop to the next can provide vastly different results as you have seen in the grimmspeed intake kit discussion.

 

We both have formulated our opinions off of testing and data we have collected which makes us both have reason to believe our own theory based off actual testing on car with the installed hardware. That is really where I would like to leave this discussion on a positive note.

 

You have nothing to prove to me and vice versa, I respect your passion and will keep an eye out if you post dyno data to see if the gains are what's expected for the extra parts and worth it in the long run for safety and longevity.

 

Dave

[Tuning Alliance]

If you are at the flow limit. I would agree.

 

Because then you would only have hotter air. So I it makes sense. With a bigger spring you will find its limits. I am just pointing out I can achieve higher pressures safely, over the stock often weak and not adjustable internal waste gate actuator.

[open.throttle]

Is it true that also a quality blow off valve that can be adjusted (spring rise etc.) can be a simple modification that will help hold boost ontop of the electronic boost controller??

[Tuning Alliance]

Is it true that also a quality blow off valve that can be adjusted (spring rise etc.) can be a simple modification that will help hold boost ontop of the electronic boost controller??

 

This would be true only if the by-pass valve currently is leaking under high boost pressure. Which even OEM's seem to hold pretty high pressure well. I have seen more issues with after market valves.