Found a very nice compressor map

I've been going through a database of turbo maps and found one from Garrett that I believe is a very good match for a "Top Gun" TDI, provided it's mated to an appropriate turbine (that search is still underway, but I've already seen some candidate GT22/23 frame-size VNT turbines with available A/R ratios of 0.74........).

The compressor can support running a pressure ratio of 3.5 (~36 PSI) @ 28 lb/min mass airflow in a single-stage with still 72% efficiency.

To put this into perspective, I calculate that you can only achieve 28 lb/min at 36 PSI boost on a 1.9 TDI with extremely good intercooling (and likely water/methanol injection), head work, cam and running the engine at 4750 RPM. With adequate and proper fuelling, this could support 280 HP on a 1.9L TDI... Note, I am not saying you will get 280 HP with this turbo; I'm saying it can support (with all of the above mods to START) this power level. You'd have to drop the compression ratio substantially, but there's some help on the subject.

Problem: It's not a compressor that I'm aware you can just find from any other OEM application. You'd have to go to Garrett and specify the whole designation C226 (60mm) 50 Trim, 0.51 A/R, and then they might reject having this compressor at all...

Where did you come across these compressor maps? I have looked at a ton of the normally available ones as well as the difficult to get ones that are like pulling teeth with Garrett and thus far not many have stood out as well as that one. I have found one which is very similar though. What is a C226 exactly?

vwmikel said:

What is a C226 exactly?

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It's Garrett's designation. They don't go by GT22, etc., because that can mean any of several dozen combinations of wheels, housings and CHRAs. Compressors start with "C" and turbines with "T".....

Is this water cooler or oil cooled? do you only have pictures of the compressor maps?

Man I wish I could see it, can anyone post a pic? My PDF thing on the computer doesn't work.

shortysclimbin said:

Is this water cooler or oil cooled?

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All compressor maps tell nothing but the operating characteristics of the compressor. As such there's no information about the centre section or turbine. All turbos will have an oil feed line, but some CHRAs (particularly for gasser engine applications) are additionally water-cooled. Conceiveably this compressor could be swapped into an existing GT22 or similar turbo.

Thanks I re-read your post this morning and saw you only found the compressor map. Google has brought up nothing yet on that number or any combination of such.

Not bad at all. Very good preasure maker. The thing is tough that you dont need that much boost for that power level. It would make one clean 280hp tough if the fuel delivery could deliver that with short enough injection. We need something with 7 holes similar of what the R520 has and it should be realy clean.

BTW would that compressor have the same shaft size as VNT turbos or is it larger? Fitting a larger wheel to a VNT shaft is doable but very time consuming.

hatemi said:

Not bad at all. Very good preasure maker. The thing is tough that you dont need that much boost for that power level. It would make one clean 280hp tough if the fuel delivery could deliver that with short enough injection. We need something with 7 holes similar of what the R520 has and it should be realy clean.
BTW would that compressor have the same shaft size as VNT turbos or is it larger? Fitting a larger wheel to a VNT shaft is doable but very time consuming.

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Hatemi: As I know you can fit IHI and MHI compressor wheels to Garrett it is the same bore.

hatemi said:

Not bad at all. Very good preasure maker. The thing is tough that you dont need that much boost for that power level. It would make one clean 280hp tough if the fuel delivery could deliver that with short enough injection. We need something with 7 holes similar of what the R520 has and it should be realy clean.

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The main question to achieving 280 HP is fuel flow, closely followed by mass airflow. Achieving an honest-to-goodness 280 HP on much less air than I have stated will be very smoky to say the least.

In my calculations, a typical well-developed TDI will have a BSFC at peak-power of 235 g/kWh or 0.385 lb/HP-hr. That means, the fuel rate required to produce 280 brake HP is 107.8 lbs/hr or 1.8 lbs/min. With the stoichiometric air-fuel ratio of Diesel fuel at 14.6:1, this would require 26.2 lbs of air. A Diesel engine requires a lambda value of at least around 1.2 to run relatively smoke free, which means an A/F ratio of 17.5:1, which means 31.4 lbs/min of air.

Now a 1.9 TDI, even heavily modified, is going to have a hard time achieving 25 lb/min air flow much less over 30 lb/min, even with 29 PSI of boost behind it and revving at 4500 RPM. Even with the above-suggested turbo it would have to run very rich for a Diesel, and getting the kind of minimum necessary mass airflow to achieve 280 HP in a TDI is the absolute flow limits of this turbo and will require serious boost pressure given the reality of only 1.9L displacement, as well as realistic assumptions for intercooler- and volumetric efficiencies.

280 HP is not an easy target to achieve in a 1.9 TDI. Sure there are a lot of experience and trial-and-error involved, but there are some rock-solid science that has to be respected.

how about this guys? http://www.turbodynamics.co.uk/ ,read this http://www.turbodynamics.co.uk/downloads/Turbo Dynamics MD479 Surpasses All Expectations.pdf
They said they got 280hp with a vnt18 hybrid on a pd150 engine with race injectors only!

IMO I find those results with only a turbo, injectors and re-map to be too good to be true, especially when we're talking about a GT1852-based turbo and 1.7 bar boost stable. The arithmetic just does not make sense.

I don't want to make any indictments, but some considerable *cough* BS *cough* in the factors converting wheel HP to crank is likely.

TDIMeister said:

IMO I find those results with only a turbo, injectors and re-map to be too good to be true, especially when we're talking about a GT1852-based turbo and 1.7 bar boost stable. The arithmetic just does not make sense.

I don't want to make any indictments, but some considerable *cough* BS *cough* in the factors converting wheel HP to crank is likely.

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Correct Meister.........i was on that dyno last year and made 296whp...LOL

mojogoes said:

Correct Meister.........i was on that dyno last year and made 296whp...LOL

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I thought it sounded "a bit" to good.

i thought so too but i just wanted to be sure

Any updates on availability on this very nice looking compressor/wheel combo?

Unfortunately, nothing from my side. Been tied up with other things. Sorry.

I'm a bit confused, Garrett does have part numbers and they look like this..
707747-0005

I've found there are only a couple 60mm compressors available from Garrett with the correct bore.

The c226 will probaly be the name and not the part number..

I still would like to have suck compressor

I need to take another look into it, but I believe that it is a Garrett-internal designation. The 6-digit+4 designation (e.g. 707747-0005) is the Garrett OEM assembly part number. C226 refers only to the compressor, and even on its own is not complete. Trim and A/R info are still missing. Like I said, I don't really know, I will have to look into it deeper. At this time, revealing more is one of those "If I tell you, I'm going to have to kill you" sort of deals. Or more likely, I will be without a job.

Arent there forum members who know inside people from Garrett / honywell turbocharger R&D?

I don't know people at Garrett personally, but I do have access to contacts. It's a delicate matter to approach someone saying, "I got your number from working at so-and-so, but I'm contacting you on an unrelated, private inquiry."

Rub87 said:

Arent there forum members who know inside people from Garrett / honywell turbocharger R&D?

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You can only ask for so many favors though and finding the right turbo is often a longer process than wearing down their patience.

vwmikel said:

You can only ask for so many favors though and finding the right turbo is often a longer process than wearing down their patience.

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You know the process well.

BTW, here is a calculation to show my suggestion of what would be needed to produce 300 HP in a 1.9 TDI, relatively smoke-free, on Diesel fuel alone (no nitrous, no propane). The background, assumptions and justifications behind the numbers can be found here.

As you can see, even the compressor above would be too small. You would need almost 34 lb/min of air flow (the criteria for relatively smoke-free operation with Diesel alone is a global Lambda value of at least 1.25, which would correspond to an AFR of about 18:1. Extremely good intercooling, and/or water/methanol injection would be absolutely necessary, as would head work/cam to achieve such high volumetric efficiencies. Achieveing maximum power of 300 HP would require around this figure to occur at around 4750 RPM with 36 PSI of boost (compressor PR of around 3.6 when IC losses are taken into account).

So it's laughable that anything near an honest 300 HP can be produced with any smaller turbocharger. In fact, 300 real HP on Diesel fuel alone in a 1.9 TDI is an extremely tall order to achieve. The science does not lie.

Even after you've got the airflow/oxygen sorted out to produce said 300 HP (or, even if you completely ignore the subject), don't even talk to me claiming 300 real HP unless you can show a fuel quantity between 90-110 mg/stroke.

That's more than triple that of a stock TDI, and between 50-70% more than the R-TDI, which was making 190 REAL HP and already using 0.260 mm injectors and a proper injection pump.

Adding further complication to this is the lack of proper dyno sheets. I'm not saying these people are all doing it on purpose but there seems to be a lack of training when it comes to dyno operators. Correction factors for such things as altitude and whatnot are also really not designed to work on forced induction engines. One thing to look at to spot a fake dyno sheet is the cross at 5252 RPM. That is the mathematical point at which torque and horsepower must cross. These bad dynos put out false ideas of what it takes to reach a certain power level. Then there's also the different types of dynomometers. Frquently the European ones calculate a hp number at the crank while US dynos are all based on wheel horsepower. I guess the bottom line here is not to beleive everything you read on the internet.

vwmikel said:

Adding further complication to this is the lack of proper dyno sheets. I'm not saying these people are all doing it on purpose but there seems to be a lack of training when it comes to dyno operators. Correction factors for such things as altitude and whatnot are also really not designed to work on forced induction engines.

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Then this thread is of interest to you.

The best and most accurate dyno types are the actual braking dynos (whether water brake or eddy current, for example), and not the inertial types. In defense of the latter, however, they can be pretty accurate IF there is also a coast-down part of the run, and the coast-down or "motoring" power is considered in the measured at-the-wheels data to arrive back to crank horsepower. Any dyno run of this type is absolutely meaningless without calibrating to the weight over the driving axle(s), so if such a weight measurement wasn't done, you might as well not even do the run.

I guess the bottom line here is not to beleive everything you read on the internet.

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And I'm telling you that applies just the same for what you read coming from ME!

TDIMeister said:

Then this thread is of interest to you.

The best and most accurate dyno types are the actual braking dynos (whether water brake or eddy current, for example), and not the inertial types. In defense of the latter, however, they can be pretty accurate IF there is also a coast-down part of the run, and the coast-down or "motoring" power is considered in the measured at-the-wheels data to arrive back to crank horsepower. Any dyno run of this type is absolutely meaningless without calibrating to the weight over the driving axle(s), so if such a weight measurement wasn't done, you might as well not even do the run.


And I'm telling you that applies just the same for what you read coming from ME!

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You make a good point in that thread. It kind of shows why you really can't compare crank and whp dynos with any degree of certainty.