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Hey guys I’m working on tuning my car right now and getting some things dialed in. I installed a new WGA (22psi Turbosmart) to replace an FP 18PSI one. After messing with the boost controller a bit I was able to hold boost a little better and get more boost across the board, but my #s on VD are essentially identical... Can anyone explain why this is the case?
The runs were both done on the same flat road, at the same spot, weather was 90-95 degrees. No knock on either pull.Only differences were that I was running an exhaust dump on the first run (Red) because I have an exhaust leak/blockage issue with the DP donut gasket and wanted to see how large the effects were of this issue. It only really affected spool up, VD dyno runs between the old 18psi WGA and exhaust dump vs old 18psi WGA and normal 3 inch exhaust were identical.
Could an exhaust leak really result in the exact same power between runs despite 2-3psi increase across the board?
Mod List: -FP Red BB with 84mm compressor cover -Greddy 264 cams -Buschur 3” inch Exhaust -Catless DP -O2 Dump -Ported Stock Exhaust Mani
-Radium Catch Can -Greddy profec-b EBC
-Turbosmart 22psi WGA -Injen Intake with amsoil filter -Perrin FMIC and full hard pipe kit -Full Blown Radiator -vivid fuel rail -PTE 1000cc injectors -Walbro 255 -Aeromotive FPR
Okay so here’s the pics....
Pretty hard to duplicate results on VD. Especially since you only added 2psi of boost, and then removed the O2 dump.
All of my runs are consistently within 5-10whp of each other. I have gone further and held 27psi all the way from 4500rpm-7500rpm but my values still remain in the 365whp range. Surely I should be seeing increases in at least the VD power curves where I am averaging an increase of 3-4psi over the total powerband? Timing has remained mostly the same, as have AFRs. Didn’t see a need to adjust anything as I am getting no knock. I have no concern for actual #s, but rather an improvement of my baseline. I see no reason why I’m not getting at least a consistent 10-20whp VD bump or more “area under the curve”, unless I am simply hoping for too much with the software?
also, how can I increase the Y value on that boost graph chart? I can’t find any setting or adjustment to make it able to read above 26psi??
can be lots of things.
spark plugs
plug wires/coils
flexy part of downpipe collapsed internally
excessive exhaust backpressure
timing isnt what you think it is
boost leak
turbo maxed out(you have a red so probably not)
you already said the timing and fueling is the same between boost levels... one degree of timing can be a significant amount of power on some cars
I'm also thinking it is from the increased exhaust back pressure. With the dump tube, the reduced back pressure allows cylinders to push more of the burnt gases out so more fresh air can enter. With more back pressure, some of these gasses remain so less of the fresh air will be sucked in. Since you are boosting a bit more, it balanced out where power is same since the oxygen molecules are about the same in both situations.
I don't see where you did any tuning after the change. If not, who knows which timing/fuel cells you in.
I know the timing/fuel cells I am hitting. I am correctly logging 1byte load with evoscan and making subsequent changes whenever I see something out of the ordinary. I am knock free and AFRs are around 11.5. The car just isn’t making more power. I suppose it is a good possibility that the excessive backpressure could be severely bottlenecking my setup at these higher pressures...will just have to see when I do some testing later this week!
Changing things that are "out of the ordinary" as in how? I mean are you actually tuning the car, or just making adjustments to keep things to avoid knock, going lean, etc? If you aren't tuning timing and other parameters to take advantage of the extra 2-3psi, then between that and the added backpressure, that could explain things.
Keeping in mind we're only using the info you've posted.
If you are actually tuning the car and still getting the same numbers, that is kinda crazy.
Changing things that are "out of the ordinary" as in how? I mean are you actually tuning the car, or just making adjustments to keep things to avoid knock, going lean, etc? If you aren't tuning timing and other parameters to take advantage of the extra 2-3psi, then between that and the added backpressure, that could explain things.
Keeping in mind we're only using the info you've posted.
If you are actually tuning the car and still getting the same numbers, that is kinda crazy.
I am working off a base map from my tuner for the car, but tweaking it to account for a few new parts now. I thought it would only take a few adjustments (increase boost, adjust WGDC, look through newly used load cells, and adjust AFRs/timing as needed for the load cells being hit while monitoring AFRs and knock) but maybe I am oversimplifying things? Would an entirely new timing map be necessitated?
This is only a temporary fix until a new and proper tune, as well as an endeavor to learn more about the tuning as a whole. It seems as though I’ve hoped for too much gain from just minor “amateur” changes lol
If you are properly tuning the car, then I'd think you should be seeing a LITTLE gain, even only adding a few psi and getting rid of the dump tube. I can't imagine ditching the dump tube would cause so much restriction.. but maybe. ..? I haven't used a dump, so I'm not sure of the difference in power that is made.
I don't know your level of tuning knowledge nor what changes you are actually making, so I can't really say if your changes are being effective. I was just trying to clarify what you meant by "out of the ordinary". That's not exactly a term I've heard a tuner use.
If you don't know how to tune a car, your best bet would be to show your logs and maps to someone who does. If you do know how, then I'm stumped, because, all other things being equal (installed properly, enough fuel, etc) you should be seeing some kind of gain.
I'm also thinking it is from the increased exhaust back pressure. With the dump tube, the reduced back pressure allows cylinders to push more of the burnt gases out so more fresh air can enter. With more back pressure, some of these gasses remain so less of the fresh air will be sucked in. Since you are boosting a bit more, it balanced out where power is same since the oxygen molecules are about the same in both situations.
This is exactly what I am thinking. Doesn't matter how much boost you throw at it. If it can't flow it wont matter. Sounds like to me that you are fighting a back pressure issue. What are you at for your wastegate duty cycle?
Is your FP Red turbo with the MHI or SS housing? From your boost curve initially, I'd guess it's their SS. But seeing that you started your pull at 3,600rpm, it looks like MHI.
This is exactly what I am thinking. Doesn't matter how much boost you throw at it. If it can't flow it wont matter. Sounds like to me that you are fighting a back pressure issue. What are you at for your wastegate duty cycle?
WGDCs are 73% up to 80% at redline.
Heres a good VD chart with those settings
Is your FP Red turbo with the MHI or SS housing? From your boost curve initially, I'd guess it's their SS. But seeing that you started your pull at 3,600rpm, it looks like MHI.
This is the MHI housing. Yeah I started the pull pretty late haha
Jul 27, 2018, 02:21 PM
lol
