944S2 16V Turbo Build
It was a new block Tom so there could have been some machining debris in there I suppose, we did give it a decent clean out though. Everything is looking good so far. I'll run it with fresh oil for another 500km and see how it goes.
I didn't know you had the elusive Jason Lee work on your engine Tom. Guessing this was some years ago?Tom wrote: Wed Oct 15, 2025 6:50 pm Well, the filter did it's job so that parts good. What was the origin of the block and other internally lubricated parts? Any chance you are just washing out someone else's debris? When Jason Lee prepped a 104mm block for me, he removed all the freeze plugs to clean the passages and insisted sludge would be left behind otherwise... Just a thought if nothing else becomes obvious...
Been doing some miles to finish the break-in and starting to get some interesting data now all of the extra sensors are working. The factory intercooler doing some solid work dropping intake temps 50degc to 7 above ambient while underway but heat soaking badly when stuck at traffic lights.
The EMAP ratio is spiking from around 1.1:1 when the wastegate opens to nearly 1.4:1, hopefully I'm not already finding the limit of the stock crossover.
The EMAP ratio is spiking from around 1.1:1 when the wastegate opens to nearly 1.4:1, hopefully I'm not already finding the limit of the stock crossover.
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It's a good heat exchanger - I wonder what pressure drop across it is?Bergerac wrote: Wed Oct 29, 2025 6:12 pm Been doing some miles to finish the break-in and starting to get some interesting data now all of the extra sensors are working. The factory intercooler doing some solid work dropping intake temps 50degc to 7 above ambient while underway but heat soaking badly when stuck at traffic lights.
The EMAP ratio is spiking from around 1.1:1 when the wastegate opens to nearly 1.4:1, hopefully I'm not already finding the limit of the stock crossover.
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For EMAP, where are you reading it? If the sensor is at turbine inlet it won't register restriction from the crossover. You will always have a decreasing pressure gradient, so if you wanted to measure restriction from the crossover you would want to measure at a port(messy signal), at the collector, and at turbine inlet. a big pressure change between any of those points would be a restriction in the piping.
If it's at turbine inlet, you either have an exhaust restriction or a turbine housing restriction. Either way, 1.4 is not terrible, just not great. Given that it's happening at only 60kpa boost, try turning it up a little and see if the ratio is maintained or gets worse.
That's some good information thanks, I'm using the original O2 sensor port with a remote damper so basically at the the turbine inlet. I wouldn't have thought you would have gotten much of a differential pressure across an open system but most of the pressure/flow measurement usually work with is in much larger pipes.
The turbo is a bit of an unknown and I had the option of a slightly used GTX3876 at the time, maybe that would have been the better option.
I probably should have run an extra wire for an pre-intercooler MAP, but I was running out of inputs. With the price of can I/O it wouldn't be hard to setup some more temporary inputs but I really want to start enjoying the car more than tinkering with it. The plan was to upgrade the intercooler down the line and it turns out my fabricator was an industrial intercooler specialist in a past life
We want to do some more miles,check the filter again and do a compression check before we up the boost but I'll definitely keep an eye on the EMAP. I have a full 3inch exhaust from the turbo back with nocat so I wouldn't have thought that would be a restriction
It's interesting even off boost the mid range torque is considebly better than NA even with the lower compression. It's really nice to drive and when the boost comes on it hits hard.
We're also chasing some inconsistent EGT readings on one cylinder, I have a feeling the probes aren't at consistent depths in the manifold so well have a look at that and look at the individual trims before turning the boost up as well.
The turbo is a bit of an unknown and I had the option of a slightly used GTX3876 at the time, maybe that would have been the better option.
I probably should have run an extra wire for an pre-intercooler MAP, but I was running out of inputs. With the price of can I/O it wouldn't be hard to setup some more temporary inputs but I really want to start enjoying the car more than tinkering with it. The plan was to upgrade the intercooler down the line and it turns out my fabricator was an industrial intercooler specialist in a past life
We want to do some more miles,check the filter again and do a compression check before we up the boost but I'll definitely keep an eye on the EMAP. I have a full 3inch exhaust from the turbo back with nocat so I wouldn't have thought that would be a restriction
It's interesting even off boost the mid range torque is considebly better than NA even with the lower compression. It's really nice to drive and when the boost comes on it hits hard.
We're also chasing some inconsistent EGT readings on one cylinder, I have a feeling the probes aren't at consistent depths in the manifold so well have a look at that and look at the individual trims before turning the boost up as well.
Its been a while, progress has been a bit slow over the last few months, we installed the KW's and all new sport hardness rubber bushes before Christmas the change is amazing, much supple thank the Konis I had in it, barely get rattled at all anymore. It even handles better and is more smooth than my wifes Kona N.
Weve been chasing a sporatic rattle that seems to originate from the variocam tensioner when the car is hot, I put a pressure sensor in the stock oil temp sensor location today to ensure we still wernt having oil pressue issues from the check valve in the head and everything looks pretty good, with a roughly 10% pressure drop from the sensor at the oil pump to the far side of the head (oil temp is usually around 90-95degC after a hard run so readings are sligtly lower than the Porsche specs which are at 80degC)
Hot Idle
Hot 5000rpm
I have a new J-tube and vario-cam check valve to install and Ill give the solenoid and spool valve a look over while I have it apart, but after that its looking increasingly like the seals in the unit itself might be passing.
Weve been chasing a sporatic rattle that seems to originate from the variocam tensioner when the car is hot, I put a pressure sensor in the stock oil temp sensor location today to ensure we still wernt having oil pressue issues from the check valve in the head and everything looks pretty good, with a roughly 10% pressure drop from the sensor at the oil pump to the far side of the head (oil temp is usually around 90-95degC after a hard run so readings are sligtly lower than the Porsche specs which are at 80degC)
Hot Idle
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I have a new J-tube and vario-cam check valve to install and Ill give the solenoid and spool valve a look over while I have it apart, but after that its looking increasingly like the seals in the unit itself might be passing.
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ROB III
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@Bergerac
Thanks for the observations on bushings and KW installation.
I've read similar results from others and your confirmation just adds fuel to the fire for me to pony up the funds to do the same. Shock technology has obviously progressed to prove control and lack of harshness can co-exist.
Thank you
Thanks for the observations on bushings and KW installation.
I've read similar results from others and your confirmation just adds fuel to the fire for me to pony up the funds to do the same. Shock technology has obviously progressed to prove control and lack of harshness can co-exist.
Thank you
Rob
89 944 Turbo
Musik-Stadt Region
89 944 Turbo
Musik-Stadt Region