New turbo for old wagon - Page 3 - PeachParts Mercedes-Benz Forum

duxthe1 · #31 01-05-2019, 12:31 AM

So I've been tuning on the car over the last week, and it's pretty impressive but as predicted earlier I think I'm against the wall of what my cold side plumbing will support. More specifically the air to water intercooler. It is one of the smaller Ebay jobs, that was rated for 300HP.

My reasoning behind this conclusion is that I can hit 16-17-18 PSI without much ado. As boost approaches the target pressure, it lowers the duty cycle of the boost control valve. I've tuned the boost control such that once it reaches the target pressure it ramps the control valve back up to full boost pulsewidth pretty much immediately. Despite the full speed ahead control, boost gradually falls as RPM climbs, typically down to 12-13 PSI. This reading is manifold pressure downstream of the intercooler. My suspicion is that its notably more at the turbo outlet.

This turbo is just starting to break into its peak efficiency island at 14 PSI and can hold it up to around 25, so this isn't an issue with the turbo running out of steam. It should be able to maintain its peak efficiency easily 100HP past where its at now.

Exhaust is full 3 inch, so I'm fairly certain it isn't a limiting factor at this power level. This leaves the intercooler looking pretty guilty. A way to prove this would be to tap my wastegate source downstream of the intercooler. This would essentially "brute force" air through the intercooler to hit and hold my target. I don't doubt this turbo would do it, though the heat produced would likely make it a futile exercise.

Soooo, I'm not going to run out and buy another intercooler right away. Enough has been spent for the time being. Not to mention... in bitter cold air, north of 5000 RPM, and north of 17 PSI, I hit 92% duty cycle on the current injectors.

sm. pelle · #32 01-15-2019, 12:17 AM

U should consider that that exhaust manifold could stop flowing at higher rpm's.
But nice to see progress and looks it's making some power.

duxthe1 · #33 01-15-2019, 02:12 AM

I'm much more suspect of the intercooler than the exhaust manifold. It's a pretty decent casting. There's even a bit of internal shaping to direct the airflow. Certainly better than a cobbled together log.

After passing emissions this past weekend I'm re-focusing my tuning efforts. The one thing that's jumping out at me is that this setup wants a lot more ignition timing under boost than the old setup. I'm still a bit conservative over about 10 PSI. Below that I keep bumping it up a little at a time and have yet to get even a hint of knock and spool keeps improving. Its common practice to add timing after the torque peak, I've just got to get past the mental block of putting uncomfortable numbers in the timing table.

nulu · #34 01-17-2019, 11:35 AM

ive got another 603 exhaust manifold if you need another one for stock, let me know , im in los angeles

atypicalguy · #35 01-17-2019, 02:10 PM

Just move the pressure tap to the cooler inlet and see what the pressure is. You cant say what efficiency island you are in unless you know what the pressure ratio is. And you cant know that without measuring turbo outlet pressure.

duxthe1 · #36 01-17-2019, 09:03 PM

I'm only set up to datalog manifold pressure, unfortunately. I'd love to be able to log pressure before the cooler to see what the pressure drop is. A lot easier said than done.

A curious thing I've noticed yesterday. After the intercooler is good and heat soaked I'm much better able to hold the high boost targets. I had a few good chances to flog it and was able to hit 18.9 PSI and hold it above 17 PSI until I let off. Manifold air temp during that log was 125-130 F degrees. I interpret that as the hot air has less mass and is able to flow through the cooler at the pressures I'm targeting. Contrast that with a run where it holds 60F manifold temps it will hit 16-17 PSI and fall back to 12-13 revving it out. I just think there is a finite mass of air I can get through the intercooler and the hotter less dense it is, the higher pressure I can hold it at. Afterall, I am trying to move 400 hp of air though a cooler rated for 300hp.

97 SL320 · #37 01-17-2019, 10:59 PM

Quote:

Originally Posted by duxthe1

I interpret that as the hot air has less mass and is able to flow through the cooler at the pressures I'm targeting.

Gale Banks is a really sharp guy. ( Plus in other vids he says black smoke from a diesel is all wrong so he gets my vote. )

https://www.youtube.com/watch?v=hbsnzC3nXOU

Why the boost gauge is dead

atypicalguy · #38 01-25-2019, 03:20 PM

Quote:

Originally Posted by duxthe1

I'm only set up to datalog manifold pressure, unfortunately. I'd love to be able to log pressure before the cooler to see what the pressure drop is. A lot easier said than done.

A curious thing I've noticed yesterday. After the intercooler is good and heat soaked I'm much better able to hold the high boost targets. I had a few good chances to flog it and was able to hit 18.9 PSI and hold it above 17 PSI until I let off. Manifold air temp during that log was 125-130 F degrees. I interpret that as the hot air has less mass and is able to flow through the cooler at the pressures I'm targeting. Contrast that with a run where it holds 60F manifold temps it will hit 16-17 PSI and fall back to 12-13 revving it out. I just think there is a finite mass of air I can get through the intercooler and the hotter less dense it is, the higher pressure I can hold it at. Afterall, I am trying to move 400 hp of air though a cooler rated for 300hp.

Dude just move the sensor, do a run, move it back.

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atypicalguy · #39 01-25-2019, 03:27 PM

Quote:

Originally Posted by duxthe1

I'm only set up to datalog manifold pressure, unfortunately. I'd love to be able to log pressure before the cooler to see what the pressure drop is. A lot easier said than done.

A curious thing I've noticed yesterday. After the intercooler is good and heat soaked I'm much better able to hold the high boost targets. I had a few good chances to flog it and was able to hit 18.9 PSI and hold it above 17 PSI until I let off. Manifold air temp during that log was 125-130 F degrees. I interpret that as the hot air has less mass and is able to flow through the cooler at the pressures I'm targeting. Contrast that with a run where it holds 60F manifold temps it will hit 16-17 PSI and fall back to 12-13 revving it out. I just think there is a finite mass of air I can get through the intercooler and the hotter less dense it is, the higher pressure I can hold it at. Afterall, I am trying to move 400 hp of air though a cooler rated for 300hp.

You assume a lot and there is no need. You have no idea where you are on the turbo map. So the turbo might simply be heating the air up (less efficient) but not moving any more mass. What you care about is grams of air per cc at the intake. It is a function of temp, pressure and humidity. And also of ambient temp, pressure and humidity. Temp is affected by ambient and by compressor and cooler efficiencies. You are forming conclusions without any data. If you want real answers, you need temp and pressure logs for ambient, pre turbo, post turbo, post cooler. Shaft speeds for the turbo would also be nice. Good luck.

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duxthe1 · #40 01-25-2019, 09:18 PM

Quote:

Originally Posted by atypicalguy

Dude just move the sensor, do a run, move it back.

If only it were that easy. This is a speed density setup so I'm fueling the engine based off the MAP sensor and moving it anywhere before the throttle isn't an option.

Quote:

Originally Posted by atypicalguy

You are forming conclusions without any data.

I'm forming conclusions with the data I have. I know I'm hitting a wall around +-350 hp and a T04E 50 trim compressor has enough headroom for 100hp more, easy. Sure I don't know exactly where I'm at in the compressor map. However if you check out the 50 trim's map, it's a beauty

with 76 and 78 % covering half of the whole damn thing. At the pressure's I'm targeting, it should be moving 25-40 lb/min and be within 76-78 % doing it.

Sure, I could invest in some fancy datalogging equipment and sensors. However, I know my intercooler is small and can be upgraded substantially cheaper than acquiring a bad ass suite of logging gear. So better intercooler is next on the list. You have to remember how this car is used. It's the winter car, cause I ain't driving the Coupe in snow. Second its used for hauling short distances for my side business during summer weekends. Third, its a touring car that occasionally humiliates douchebag beemer owners and makes WRX owners google "How do I turn up boost"

Of course lots of cars are faster, but very few are more of a sleeper.

atypicalguy · #41 01-25-2019, 10:44 PM

Quote:

Originally Posted by duxthe1

If only it were that easy. This is a speed density setup so I'm fueling the engine based off the MAP sensor and moving it anywhere before the throttle isn't an option.

I'm forming conclusions with the data I have. I know I'm hitting a wall around +-350 hp and a T04E 50 trim compressor has enough headroom for 100hp more, easy. Sure I don't know exactly where I'm at in the compressor map. However if you check out the 50 trim's map, it's a beauty

with 76 and 78 % covering half of the whole damn thing. At the pressure's I'm targeting, it should be moving 25-40 lb/min and be within 76-78 % doing it.

Sure, I could invest in some fancy datalogging equipment and sensors. However, I know my intercooler is small and can be upgraded substantially cheaper than acquiring a bad ass suite of logging gear. So better intercooler is next on the list. You have to remember how this car is used. It's the winter car, cause I ain't driving the Coupe in snow. Second its used for hauling short distances for my side business during summer weekends. Third, its a touring car that occasionally humiliates douchebag beemer owners and makes WRX owners google "How do I turn up boost"

Of course lots of cars are faster, but very few are more of a sleeper.

It is all very cool. Nice work.

How do you know you are at 350hp again?

And yes throwing parts at a car is somewhat satisfying and a larger intercooler isn't going to hurt anything. But at that point, where will you go for more power? bigger compressor? bigger turbine? smaller turbine? Even bigger intercooler?

If I were you, which I am not, I would just cough up the 350 or whatever for that Banks iDash with an air mouse, move it all over and log until you have a better idea what to optimize. I'm sure someone will give you 250 for it on ebay when you are done with it, and you won't be guessing about flow restrictions any more, or air density, or whether you have enough lb/min to make the power you are after.

duxthe1 · #42 01-26-2019, 01:48 AM

My 350 hp estimate is based on fuel flow, IE injector size v/s duty cycle. The T04E 50 trim should have more than enough airflow to max out my injectors. I can get close pushing it hard during warmup enrichment, but under normal conditions (AFRs) it hits the wall around 80% duty cycle. Previous turbo did a best of 68% The eventual goal is to get my injectors to ~95% duty cycle. Should be in the neighborhood of 400hp depending on how you figure VE and BSFC.

whipplem104 · #43 01-27-2019, 10:56 AM

You could easily put a few sensors on and log and monitor them through the TCM. I do not know which ones you are already using but if you are still only using MAP or TPS then you would have 3-4 more channels to use. Although sensors do add up.

duxthe1 · #44 01-27-2019, 04:18 PM

That would work but TCM is in the coupe and turbo is in the wagon. ��

whipplem104 · #45 01-27-2019, 07:24 PM

Well there is your problem the wagon needs a 722.6.