Twin Turbo 928 fixed and back out there terrorizing the streets!
#46
Nordschleife Master
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When in doubt data log, data log, and data log some more. Still baffles me how little people actually measure. Install a fast acting temp sensor after the IC, if the temps are within the desired range, no need to go changing anything. I know some who would go as far as measuring the pressure, velocity etc... of the air in the chamber before the IC.
Among the many sensors being installed are:
- Turbocharger speed sensor that measures the rpm of the turbine-compressor shaft. This is useful for optimizing bypass valve spring load for shifts etc.
- Outside temperature sensor inside the IC duct. This is useful in computing the intercooler effectiveness.
- The pre-turbine exhaust back pressure. This is useful in calibrating the simulation software to match the exact turbine (EAP can't accurately match turbos without these data) and in selecting the camshaft profile.
I did independently confirm the presure differential between the wheelwell and the bumper face separately using silicon hoses and a manometer. That was a one-time job on route 2. John had of course done this earlier, but I just had time to kill.
#47
Administrator - "Tyson"
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#1 suggestion that comes to mind is test the temp senders before installing them (heat gun / hair dryer etc..)
Two reaons.
1. Avoid installing a broken one
2. Make sure they are sensitive enough.
Most cannot react fast enough for an accurate reading of intake air. Any old water / oil etc... sender will not be accurate.
I'm still playing with a few myself. I just had Todd install two different units above my TB in the plenum. We'll see how they compare. By the time I'm done installing sensors (not until after SITM) I'll have at least 5-6 intake air temp readings.
Two reaons.
1. Avoid installing a broken one
2. Make sure they are sensitive enough.
Most cannot react fast enough for an accurate reading of intake air. Any old water / oil etc... sender will not be accurate.
I'm still playing with a few myself. I just had Todd install two different units above my TB in the plenum. We'll see how they compare. By the time I'm done installing sensors (not until after SITM) I'll have at least 5-6 intake air temp readings.
#48
Nordschleife Master
Thread Starter
I think you could adapt Garrett's turbocharger speed sensor to the centrifugal supercahrger unit. I don't know much about belt-driven stuff, but I vaguely recall that centrifugal units need a belt that can slip a little. Getting the actual speed reading and comparing that with the engine speed will allow you to compute the belt slippage and also to exactly pinpoint the location on the compressor map.
#50
Burning Brakes
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What sensors are you using to monitor EGT and exhaust backpressure? I would be interested in getting a set for myself if you have details. Actually, details on all of your sensors would be delightful. Thanks!
#51
Nordschleife Master
Thread Starter
The turbocharger speed sensor is from Garrett. It's on their web site. Install's to the compressor housing.
The whole data logging system beyond John's standard product is still work in progress.
#52
Burning Brakes
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If it helps, I think I read about Louie Ott's individual cylinder EGT monitoring system. I can't find the post right now, but he used some sensors hooked up right out of the manifold. I would use those, if I could find the link...as for pressure, they must exist somewhere...
#53
Nordschleife Master
Thread Starter
If it helps, I think I read about Louie Ott's individual cylinder EGT monitoring system. I can't find the post right now, but he used some sensors hooked up right out of the manifold. I would use those, if I could find the link...as for pressure, they must exist somewhere...
#54
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New school way is to use those ports to monitor lean/rich condition, especially if you have an aftermarket ECU that can do clyinder-specific fuel trim
Like this?
https://rennlist.com/forums/928-foru...ds-garage.html
#56
EGT monitoring is old school. New school way is to use those ports to monitor lean/rich condition, especially if you have an aftermarket ECU that can do clyinder-specific fuel trim. I think that requires another eight tubes down there, since wideband o2 sensors will not live in the cylinder head exhaust port.
When I found this out, I asked questions of the people involved in the ECU market. I found two, and two only:
Autronic (which Todd uses)
Pro EFI 128*
* This is an untested system as far as I am concerned, but its promising.
#57
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Have you found an aftermarket ECU that has Fuel trims per cylinder on a load basis? Instead of just on a global percent basis, which does nothing if the intake is not perfectly matched to each cylinder. That does not exist in the S4 intake manifold, and Todd found that some had over 20% difference, up or down, according to the revs and load.
When I found this out, I asked questions of the people involved in the ECU market. I found two, and two only:
Autronic (which Todd uses)
Pro EFI 128*
* This is an untested system as far as I am concerned, but its promising.
When I found this out, I asked questions of the people involved in the ECU market. I found two, and two only:
Autronic (which Todd uses)
Pro EFI 128*
* This is an untested system as far as I am concerned, but its promising.
#58
Percentage change in trim does not factor load.
#59
Nordschleife Master
Thread Starter
Yes, but it's a lot better than nothing.
#60
Nordschleife Master
I would caution against putting any O2 sensor pre-turbine. There is too much heat there and it will cook them in a BIG hurry. That is even with a copper heat sink.