possible boost creep?
4 Attachment(s)
Finally have my mx5 based kit car on the road. Getting it properly tuned on the rolling road in 3 weeks so I'm mainly trying to test all my hardware is working properly.
Spec (in brief) is: 1.8bp engine ms2 td04 turbo from WRX rx8 injectors water to air intercooler 3" diy exhaust I have a boost control solanoid setup but have it on wastegate pressure (signal taken at the inlet manifold) to be safe until I get it on the dyno. Anyway I had to relocate the wastegate actuator and used a saab one that is supposed to open at 5 psi. Have done a few datalogging runs and was a alarmed to see close to 11 psi and high inlet temp. I have tested the wastegate and actuator operation with a bike pump on the signal line and it works ok. Can't confirm the pressure. I was wondering if boost creep could be the cause. I guess that is the wastegate opening but failing to bypass enough gas. However my gut feeling is that its not going to happen on a mild setup like this. The boost seems to taper off and then increase again during a roll on. Anyway here is a datalog of a 4th gear roll on. Closest I could get to dyno conditions on the road. If someone with more experience then me could take a look at it and let me know what they think that would be appreciated. |
(signal taken at the inlet manifold) You can also disconnect the WGA arm and wire the WG open to know for sure what kind of creep is due to Turbo / Exhaust manifold / DP. On my TD04, with segregated downpipe, I get about 5psi at 7k RPM with WG wired open. 11 psi sounds like a high WGA setting, or a leak somewhere. Take off the line from the WGA. Pull the arm out, plug the nipple (finger will do). If is retracts, then the diaphram is bad. If your Air-Water were working properly, 11 psi should not cause high MAT. Are you the guy we tried to discourage from such a set-up? |
1 Attachment(s)
Originally Posted by DNMakinson
(Post 1229849)
Picture or better description of the location of the WG signal source, please.
You can also disconnect the WGA arm and wire the WG open to know for sure what kind of creep is due to Turbo / Exhaust manifold / DP. On my TD04, with segregated downpipe, I get about 5psi at 7k RPM with WG wired open. 11 psi sounds like a high WGA setting, or a leak somewhere. Take off the line from the WGA. Pull the arm out, plug the nipple (finger will do). If is retracts, then the diaphram is bad. If your Air-Water were working properly, 11 psi should not cause high MAT. Are you the guy we tried to discourage from such a set-up? I am indeed the guy you tried to discourage from such a setup. That being said I have tried to use large radiator, large pipework decent pump to get the heat out as quick as possible and I really can't imagine fitting a reasonable sized air/air unit in the nosecone. https://www.miataturbo.net/attachmen...ine=1431104744 |
move that source to pre-tb or you'll have massive boost spikes
|
Originally Posted by 18psi
(Post 1229862)
move that source to pre-tb or you'll have massive boost spikes
|
Excellent! Knew I was doing something wrong.
Care to elaborate why? I can see why the signal would be higher at the turbo outlet - not sure why post TB is bad. |
because with a partially closed butterfly the manifold see's a whole lot less boost than the rest of the system
making your turbo huff its lungs out trying to catch up |
Thanks! I'll try it straight off the turbo nipple tomorrow
|
All times are GMT -4. The time now is 03:44 AM. |
© 2024 MH Sub I, LLC dba Internet Brands