MyE28.com

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Thats what the turbo 2.7i pulled at the dyno today. These are uncorrected figures, at the wheels. HP scale on the left goes up to 250, torque on the right goes to 275. The dynojet correction factor for 5500 feet moves the HP scale up to 300 and the torque to 350. So, at the wheels without altitude correction it made 230 HP and 265 TQ. Corrected for altitude with an SAE factor of 1.2, it came up with 276 HP and 320 TQ at the wheels.

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And check out the tuned-AFM air-fuel ratio. About 11 to 11.5 to 1 under boost. A bit rich, but very safe. The only thing I don't quite get is the torque falling off like it does. Its a full on 2.7i, with the high winding 325i cam. I'm betting its either the turbo diesel manifold or turbine housing choking up. I'll be pulling them off for more porting shortly, as it seems like theres a lot more HP in there if it would wind out a bit more.

Even as it is, I'm still very satisfied with the results. I'm not sure about the correction factor though. To be conservative, you could use a factor of 1.1 for altitude and another .2 for driveline losses. A total correction factor of 1.3 gets me 300 HP at the crank at sea level. If the factor of 1.2 is appropriate for 5500 feet, and you also consider driveline losses, it could be making as much as 320 HP, 380 TRQ at the crank. Not too bad for a turbo diesel manifold. I'll run it again when I gut the td casting a little more and install a MAF kit. Stay tuned...

Not bad at all!

Do you have a boost gauge? Do you loose boost after 5,000rpm? It seems to me that you might be losing boost, perhaps your turbo is too small, might be the manifold too , but I think its the turbo, if I remember correctly you are using a standard T3. you'd probably want at least a t4 compressor side.
I've heard good things about holset hx35.

It'll make 10-11 psi all the way up. The GT2560R compressor is efficient to over 300whp, but I'm not sure if the .64 A/R turbine and 53mm turbine wheel are large enough to keep up on the tippy-top end. I'm planning on opening up the wastegate port and the manifold runners next time I'm in there. Maybe that'll do it, because it doesn't have a problem maintaining boost.

Damn fine #'s. I am certainly surprised they were that high. Nice work Dan. You've done a great job. I am looking forward to your next stage of improvements.

Great results! My thoughts:

-AFRs are nice and safe. Leave them that way.
-It's a 6000rpm motor. Do not rev it out to 6800!
-Turbo motors are better represented by uncorrected numbers at elevation.
-Excellent results!

6800 would definitely be over revved. You can feel the torque dropping off. If I could stretch that torque hump to 5500 or so I'd be really happy with it. I do think some correction factor is appropriate for altitude, because it would make more absolute pressure at sea level with the same amount of boost. It might only be worth another 3 or 4 lbs/min of air, but thats significant enough to consider for comparison.

turbodan wrote: I do think some correction factor is appropriate for altitude, because it would make more absolute pressure at sea level with the same amount of boost. It might only be worth another 3 or 4 lbs/min of air, but thats significant enough to consider for comparison.

Not 20%. I would say your figures are within 5%.

Todd

turbodan wrote:6800 would definitely be over revved. You can feel the torque dropping off. If I could stretch that torque hump to 5500 or so I'd be really happy with it. I do think some correction factor is appropriate for altitude, because it would make more absolute pressure at sea level with the same amount of boost. It might only be worth another 3 or 4 lbs/min of air, but thats significant enough to consider for comparison.

Actually, since we're talking "absolute pressure" with turbos, you don't lose much of anything on boost at altitude, the turbo just has to push a little more air to make the same manifold pressure than it would at sea level. This is one of the advantages of a turbo and altitude, no power loss.

Jeremy

It depends on the type of pressure gauge used. If the sensor is measuring with respect to its surrounds, then the correction factor should be used(thats gauge pressure). If it is measuring with no reference, then its absolute, and no correction. Is the sensor used an absolute or referenced?

I believe most are gauge sensor's. So the correction factor of 20% for 5500ft would be appropriate.

RussC

T_C_D wrote:

turbodan wrote: I do think some correction factor is appropriate for altitude, because it would make more absolute pressure at sea level with the same amount of boost. It might only be worth another 3 or 4 lbs/min of air, but thats significant enough to consider for comparison.

Not 20%. I would say your figures are within 5%.

Todd

russc wrote: I believe most are gauge sensor's. So the correction factor of 20% for 5500ft would be appropriate.

RussC

Except that a m20b27 i conversion just doesn't make that much power at 10psi. 276/320 at 10psi isn't accurate. I would be willing to bet $500 that 276/320 is way overstated.

Then his gauge is abosolute.

RussC

T_C_D wrote:

russc wrote: I believe most are gauge sensor's. So the correction factor of 20% for 5500ft would be appropriate.

RussC

Except that a m20b27 i conversion just doesn't make that much power at 10psi. 276/320 at 10psi isn't accurate. I would be willing to bet $500 that 276/320 is way overstated.

Jeremy wrote:

turbodan wrote:6800 would definitely be over revved. You can feel the torque dropping off. If I could stretch that torque hump to 5500 or so I'd be really happy with it. I do think some correction factor is appropriate for altitude, because it would make more absolute pressure at sea level with the same amount of boost. It might only be worth another 3 or 4 lbs/min of air, but thats significant enough to consider for comparison.

Actually, since we're talking "absolute pressure" with turbos, you don't lose much of anything on boost at altitude, the turbo just has to push a little more air to make the same manifold pressure than it would at sea level. This is one of the advantages of a turbo and altitude, no power loss.

Jeremy

Well, the way I understand it, at high altitude you have a big loss at the compressor inlet. I might have 12 psi at the tips of the compressor blades. If I make 10 psi of boost, thats a pressure ratio of about 1.83. Absolute pressure in the manifold is about 22 psi. Thats due to the atmospheric pressure reference on the GT2560R's internal wastegate. It controls the pressure ratio, not the boost. If the pressure on one side of the diaphragm is 1.83 times higher than the other, it opens the wastegate.
So if its making 22 psi AP up here:
12 psi compressor inlet + 10 psi boost = 22 MAP 22/12=1.83
14.5 sea level inlet pressure *1.83 pressure ratio = 26.5 MAP
If that is correct, I'd need another 4.5 psi to be moving the same amount of molecules. 4.5 psi is a significant amount. If someone would have put a cork in the little hole in the wastegate body before they shipped it from California, I'd be set. But it was shipped un plugged, so it sees only 12 psi on the atmospheric side of the wastegate diaphragm. So I'm stuck with the weak suck pressure ratio of 1.83. Unless I increase the boost (aka pressure ratio) the compressor spins just as quickly as it does at sea level. So I take in the same volume of air up here at 12 psi as I would at sea level where the grass is greener and the air pressure at the compressor inlet is about 14.5 psi.

Or perhaps I need to take it and the dyno I used down to SoCal and actually test the hypothesis. My next vacation seems to be shaping up...

russc wrote:Then his gauge is abosolute.

RussC

T_C_D wrote:

russc wrote: I believe most are gauge sensor's. So the correction factor of 20% for 5500ft would be appropriate.

RussC

Except that a m20b27 i conversion just doesn't make that much power at 10psi. 276/320 at 10psi isn't accurate. I would be willing to bet $500 that 276/320 is way overstated.

No, its not absolute. It may be broken, but its not absolute.

Is a wastegate referenced or absolute? I'm guessing referenced, so I guess I was wrong. Will I make more/less boost (on the gauge, which I guess is referenced since it reads 0 with the car off) at higher altitude?

Jeremy

Let me clarify my obnoxious comment. These motors make an extremely predictable amount of power. I consider our systems pretty optimized. The m20b25 makes about 11rwhp/11rwtq per psi of boost on a good tune. The m20b27 makes the same HP and slightly more HP per psi. Figure a hybrid 2.7i makes 145rwhp/160rwtq in stock form. Very best case scenario 10psi adds 110rwhp/120rwtq. That would equal 255rwhp/280rwtq with a very good setup and exhaust. That may be possible on your setup but 276/326 is highly unlikely IMHO.

Secondly I do not think your 24lb injectors will support 326rwtq especially as rich as it is tuned. 24lb injectors on my m20b25 would only safely support 265rwhp/265rwtq.

Todd

So I gather that turbodan's M20 was running roughly about 1bar of boost?

and I think he has a Begi RRFPR FMU, that with 24lbs. injectors is not enough?

Jeremy wrote:Is a wastegate referenced or absolute? I'm guessing referenced, so I guess I was wrong. Will I make more/less boost (on the gauge, which I guess is referenced since it reads 0 with the car off) at higher altitude?

Jeremy

My wastegate is referenced to atmospheric pressure. You will probably make the same amount of boost at a higher altitude, but since the atmospheric pressure is lower, you wont have as much absolute pressure in the manifold. So you lose power. But that would depend on your wastegate. If it has any kind of atmospheric reference, you wont make as much power at higher altitudes.

TCD wrote:Let me clarify my obnoxious comment. These motors make an extremely predictable amount of power. I consider our systems pretty optimized. The m20b25 makes about 11rwhp/11rwtq per psi of boost on a good tune. The m20b27 makes the same HP and slightly more HP per psi. Figure a hybrid 2.7i makes 145rwhp/160rwtq in stock form. Very best case scenario 10psi adds 110rwhp/120rwtq. That would equal 255rwhp/280rwtq with a very good setup and exhaust. That may be possible on your setup but 276/326 is highly unlikely IMHO.

Secondly I do not think your 24lb injectors will support 326rwtq especially as rich as it is tuned. 24lb injectors on my m20b25 would only safely support 265rwhp/265rwtq.

Todd

Well, all there really is to debate is the correction factor. Uncorrected, it made 230 RWHP and 266 RWTQ. Thats at about 22 PSI MAP. I can say for sure that I'm missing some from what it would do at sea level for the same boost due to the atmospheric reference on the wastegate. Like I said, I'm pretty sure the atmospheric reference on the internal WG maintains a specific pressure ratio, not a specific manifold pressure. So if I dyno'd it at sea level it should do significantly better for the same 10 PSI. Probably about 30 lbs/min up from a (estimated by calculation) 25.8 lbs/min up here in Albee-querque. If its a roughly linear relationship between airflow in lbs/min and RWHP, it should do over 260 RWHP at sea level. I dont know about RWTQ, but I bet it'd be around or over 300 foot pounds if it made 266 at the wheels with 22 PSI MAP. 26 PSI MAP is quite a bit more for the same 10 PSI, in any case. I guess the only way to test these theories would be to run it at sea level.

I'm not sure what to think about the injectors. I think at the stock duty cycle with a rising rate FPR, I could probably get away with quite a bit of power. They're only 24 lber's at 3 bar. I know the Cartech reg will go higher than that. I was doing 7 psi (probably about 19 MAP) on the stock 14.75 lb injectors with the RRFPR maxed out without detonation. Shit, thats what I was running when it walked a new Charger Daytona R/T. With that in mind, I'm not too worried about injector size only making three more PSI in the manifold with an extra 9 lbs of injector. Either way, it'll be running at 5500 feet for the rest of its service life, so it'll only be doing 230 RWHP and 266 RWTQ unless I end up turning up the boost again. Until then, its more than safe.

I believe that with the info TurboDan is giving us, the 20% correction is correct, and the gauge reading the pressure is absolute.

If his WG is referenced to ambient, then his pressure of 11.5psi would be 20% higher at sealevel, ~15psi which is the standard that the industry adheres to. So his whp # should be bumped up 20%. Thats the math....

Now, can his system make 276whp. Well, we all know there is a large margin of error from dyno to dyno, even with DynoJets. And, some engines just work better than others, and he may have one of those engines. For what ever reasons, maybe piston sealing, less bearing friction ect ect he may have a rare engine/drivetrain combo that has less loss. Some will be higher, some will be lower.

Im not saying that his # is the end all-ball, but he may have really make 276whp also, it is possible, however small.

RussC

T_C_D wrote:Let me clarify my obnoxious comment. These motors make an extremely predictable amount of power. I consider our systems pretty optimized. The m20b25 makes about 11rwhp/11rwtq per psi of boost on a good tune. The m20b27 makes the same HP and slightly more HP per psi. Figure a hybrid 2.7i makes 145rwhp/160rwtq in stock form. Very best case scenario 10psi adds 110rwhp/120rwtq. That would equal 255rwhp/280rwtq with a very good setup and exhaust. That may be possible on your setup but 276/326 is highly unlikely IMHO.

Secondly I do not think your 24lb injectors will support 326rwtq especially as rich as it is tuned. 24lb injectors on my m20b25 would only safely support 265rwhp/265rwtq.

Todd

Great numbers, nonetheless. It's awesome to finally see some data posted on the diesel manifold. Good job.

I'm thinking that correcting the boost pressure is more agreeable than boosting the output for altitude. So its more like 230 RWHP and 266 RWTQ at 7.5 psi (+14.5 at sea level = 22 psi MAP), which seems fair enough.

At altitude you also get a vacuum in the exhaust, thats aiding in the removal of the air .

i.e ambient pressure is not 1bar, it´s 0.95bar or something to that affect. so you get less pressure infront of the turbo but on the same time you get less on the other side , and that basically sucks out the air from the exhaust, or in other words, there is less pressure to overcome with the exhaust gases.