Thanks for sharing, I will try these settings.
None of my acceleration enrichments have worked well enough for me. I'll give this a try this weekend or early next week and maybe see what it looks like on the datalog as well.
I always seem to have rich on tip wn, though I hD it dialed in ok previously with tps only enrichment. But it's always a bit rich in throttle lift, and has never felt like what I would call snappy for throttle response. Could be related to my intake and intercooler piping length maybe...
Turbo ETA build
Re: Turbo ETA build
That's what I really like about EAE, it corrects the mixture continuously to maintain a stable AFR. Adds a percentage on throttle application and pulls some back as you lift off. It has the potential to save quite a bit of fuel, and when it works well it makes a remarkable difference. If you're running 13:1 across the map, a 10% deviation from stoich is no big deal. At 14.7:1 it is a huge problem, but EAE makes it possible. TPS based AE will never work well for slow throttle movements. A whole lot happens below a rate of 20%/sec during normal driving, but at least for me the noise in the TPS signal makes it unsuitable below that rate.
Those settings are working well from about 100-120 degrees on up to operating temperature. At operating temp, they are fantastic. Below 100, I think there is still more work to be done. Yesterday I took a bit of fuel out of the added to walls coolant temp correction curve and cut back the added PW and percentage for cold TPS based enrichment, which was a step in the right direction. I would rather be a little lean than rich enough to misfire, though either option is irritating. There is an ideal balance of WUE and acceleration enrichments and I intend to continue dicking with it until I'm confident that it's as good as it gets. No matter what, it seems that I end up rich at low kpa and lean at high kpa. This may be attributable to the characteristics of the fuel. It vaporizes more readily under vacuum at cold temps, but once the throttle is opened it requires additional enrichment. When the engine is hot, it vaporizes more consistently at all manifold pressures. I would love to find a pressure temperature chart for gasoline, that would be very interesting. The freezing point is about 100 below zero, and it boils at around 150 degrees, but we would need to see a PTC to understand the effect that manifold vacuum has on the phase of the fuel. On a cold start, with the cylinder head at 19 degrees, the fuel certainly behaves differently.
As it sits right now, I added in some extra WUE and pulled back the acceleration enrichment coolant correction factors. The basic EAE coefficients and RPM correction factors are still good, once the temp gauge is into the blue it's starting to run well. I have the EGO control coming on around 75 degrees if I remember correctly, and I've allowed it 8% authority. This may be the way to go, set it up rich enough to drive smoothly and let the O2 sensor handle the rest.
The original turbo car was tuned to run open loop, probably around 13:1 most of the time. It was so much easier only using TPS AE, not giving a shit if it was rich when I lifted off the throttle. Probably stunk to drive behind that thing, running rich with no cat. That won't do this time around.
Those settings are working well from about 100-120 degrees on up to operating temperature. At operating temp, they are fantastic. Below 100, I think there is still more work to be done. Yesterday I took a bit of fuel out of the added to walls coolant temp correction curve and cut back the added PW and percentage for cold TPS based enrichment, which was a step in the right direction. I would rather be a little lean than rich enough to misfire, though either option is irritating. There is an ideal balance of WUE and acceleration enrichments and I intend to continue dicking with it until I'm confident that it's as good as it gets. No matter what, it seems that I end up rich at low kpa and lean at high kpa. This may be attributable to the characteristics of the fuel. It vaporizes more readily under vacuum at cold temps, but once the throttle is opened it requires additional enrichment. When the engine is hot, it vaporizes more consistently at all manifold pressures. I would love to find a pressure temperature chart for gasoline, that would be very interesting. The freezing point is about 100 below zero, and it boils at around 150 degrees, but we would need to see a PTC to understand the effect that manifold vacuum has on the phase of the fuel. On a cold start, with the cylinder head at 19 degrees, the fuel certainly behaves differently.
As it sits right now, I added in some extra WUE and pulled back the acceleration enrichment coolant correction factors. The basic EAE coefficients and RPM correction factors are still good, once the temp gauge is into the blue it's starting to run well. I have the EGO control coming on around 75 degrees if I remember correctly, and I've allowed it 8% authority. This may be the way to go, set it up rich enough to drive smoothly and let the O2 sensor handle the rest.
The original turbo car was tuned to run open loop, probably around 13:1 most of the time. It was so much easier only using TPS AE, not giving a shit if it was rich when I lifted off the throttle. Probably stunk to drive behind that thing, running rich with no cat. That won't do this time around.
Re: Turbo ETA build
Slight EAE tweaks:
Better still during warm up. I also moved one of the low kpa bins on the SFW coefficient and increased the low end of that curve a little more. Overall it's working great without a whole lot of TPS AE.
I ordered a new turbo too. Got tired of trying not to buy a new turbo, this was the only solution. The price seems too good but it does appear to be a genuine Garrett. We'll see what it gets here. Seller appears to be legit and it is discontinued by Garrett, they might just be trying to get rid of them.
This is the .86 AR variety. I believe that was the same turbine wheel and housing I was running with the GT2871R back in 2007 or 2008. It worked very well, not too sleepy but it had enough capacity to avoid choking up on the top end.
I figure it's about time to put spark plugs in this thing. This set has a few miles on them. I'll be taking the turbo off for that and a valve clearance check and I didn't really want to put the little GT2560R back on. It's been great but its not efficient beyond about 11 psi. Since the stock clutch and fuel pump seem to be capable of at least 1 bar, I'll be running 1 bar. Looking at the compressor map, this thing is capable of making 450+ rear wheel. I would want to go for a larger and more efficient turbine if I was going to push it that hard, though running in the 300ish horsepower range will be no trouble at all.
Better still during warm up. I also moved one of the low kpa bins on the SFW coefficient and increased the low end of that curve a little more. Overall it's working great without a whole lot of TPS AE.
I ordered a new turbo too. Got tired of trying not to buy a new turbo, this was the only solution. The price seems too good but it does appear to be a genuine Garrett. We'll see what it gets here. Seller appears to be legit and it is discontinued by Garrett, they might just be trying to get rid of them.
This is the .86 AR variety. I believe that was the same turbine wheel and housing I was running with the GT2871R back in 2007 or 2008. It worked very well, not too sleepy but it had enough capacity to avoid choking up on the top end.
I figure it's about time to put spark plugs in this thing. This set has a few miles on them. I'll be taking the turbo off for that and a valve clearance check and I didn't really want to put the little GT2560R back on. It's been great but its not efficient beyond about 11 psi. Since the stock clutch and fuel pump seem to be capable of at least 1 bar, I'll be running 1 bar. Looking at the compressor map, this thing is capable of making 450+ rear wheel. I would want to go for a larger and more efficient turbine if I was going to push it that hard, though running in the 300ish horsepower range will be no trouble at all.
Re: Turbo ETA build
The suspiciously inexpensive GT2876R looks like the real deal. It did not come with a wastegate actuator bracket but I think I can sort that out. The compressor inlet is 4 inches in diameter so my intake plumbing will need work too. I hope the compressor housing clears the valve cover, it's definitely larger.
I used a coffee can here on one of the past builds. Some people didn't like that but I never had a problem with it.
Re: Turbo ETA build
Would you think of using a external gate? or is a internal better for what you are doing?
Re: Turbo ETA build
I know turbineresearch was doing 24 PSI at 560 on the OG headgasket. i love the m20 and the m30. when i do research for the m20 turbo i come looking for your post. turbineresearch m30 info is amazing to if you havnt you should check him out he is a cool guy with alot of info. with the m30 turbo's https://www.youtube.com/shorts/JPQpku4x4Z8turbodan wrote: Feb 24, 2023 9:18 PM I've always liked the M20. The M30 is heavier and less fuel efficient. The M20 with the 2.5 top end makes great high rpm power too, whereas the M30 requires more extensive modification for that 6000 RPM+ power. My 2.7i with the GT35R was making peak power at 6400 and it was hanging onto something like 90% of that until 7000. Full boost at 4000 and nothing but fun from there on up. That was probably my favorite aspect of the small six.
As it turns out it's a great motor for boost in terms of durability too. The smaller bore diameter helps avoid detonation and I think the super ETA/2.5 combustion chambers seem to help a little more. I may be mistaken but I think the M30 head gaskets are more delicate. I was doing very well at 21 psi with a stock gasket and head studs. I believe the M30 needs an MLS to approach those boost levels and then you have the usual MLS stuff to deal with. I've had hit and miss results with those, including one that failed only after a buyer had flown in from goddamn Michigan to buy the car and drive it back.
MPG was in the 20s. Best I ever saw was 27. Surely could be better with a more careful tune. This time around I will be using a narrowband 02 sensor for closed loop operation. Easy MPG there.
Re: Turbo ETA build
External works better and is more efficient. Less turbulence at the turbine outlet and a better pressure ratio through the turbine. Internal works pretty well though and simplifies packaging and plumbing. Best ET I ever ran was with the internally gated GT2871R.Notae30 wrote: Dec 25, 2024 8:34 PM Would you think of using a external gate? or is a internal better for what you are doing?
The most efficient system I ever had was the externally gated GT35R. Big turbine, external dump on the wastegate. It made boost with minimal backpressure, which improves the intake/exhaust pressure ratio. Higher volumetric efficiency, greater resistance to detonation. I ran a lot more timing with that system than I could with any of the smaller, internally gated turbos.
Turbine efficiency is not often discussed but it is important. Ten percent here makes a significant difference.
Re: Turbo ETA build
That big-ass compressor housing posed some challenges, but it does fit. I had to make a bracket for the wastegate actuator and the compressor outlet required clearancing the turbine flange and edge of the manifold. I meant to check valve clearances while I was in there but after all of the unexpected fuckery had been sorted out I didn't get around to it.
The boost comes on around 3000 RPM. Feels very good at .8 bar, stronger especially on the top end. I haven't put a wideband on it yet but I did add in a touch of fuel in case it's breathing better.
It's better in a way that it's not trying to spool up everywhere, all the time. I do have to downshift to get down to business now, no more 1500 RPM spoolup. That's okay though, it seems happier with the larger hot side.