|
|
Post by oldschoolmk on Sept 14, 2018 1:08:38 GMT
|
|
|
|
Post by yogidave on Sept 20, 2018 21:51:18 GMT
Here's my boost leak test (attempt, anyway): first is the entire time frame of the test drive while logging, second is just a blow up of one region to see detail better. So, either we BOTH have a leak, or we are both getting similar results. I will say you "actual" seems to be lagging your "specified" by what looks like a lot, so it could be a leak. NOTE: I have no friggin clue what I'm talking about. probably.   |
|
|
|
Post by oldschoolmk on Sept 21, 2018 21:00:29 GMT
I did learn some stuff that didn't occur to me previously. I was thinking i was getting 1720 mBar of boost. not taking into account my Naturl Atmospheric pressure of 1010 mBar. So there is that factor. Have to Minus your regions atmospheric pressure (your mBar at idle) from your boost actual to get a proper boost number. Aditionally I did a Highway pull or two in 4th gear. I will post here after i convert it over to my Computer
|
|
|
|
Post by oldschoolmk on Sept 21, 2018 22:37:23 GMT
Here is a 4th Gear Highway pull. No boost leaks.   |
|
|
|
Post by Matthew on Oct 5, 2018 20:12:46 GMT
Have to Minus your regions atmospheric pressure (your mBar at idle) Real Atmospheric pressure can only be measured with your ignition ON, (but engine OFF), with the throttle-body cracked open slightly (you can press the accelerator pedal. That's the value you use for atmospheric pressure in your region. It may be 1,010 or 1,013mBar, etc. Having the engine at idle, is not an acceptable method of measuring atmospheric pressure as your turbine is ALWAYS turning and the compressor generates a tiny bit of boost no matter how minute it may be thus throwing off your subtraction. There is another school of thought that the presence of a boost leak can be discovered by abnormally high wastegate duty cycles. The duty cycle will be low around 1,800 - about say 3,000 RPM, for little to no leaks when going uphill. If your wastegate duty cycle exceeds 80% at any point, you have a problem. When you know you have a problem is when you exceed 80% (stock) wastegate duty at any RPM. It becomes obvious over about 4,500 RPM Edit: I agree with the OP about not having a boost leak. Your graph has the correct shape. I'd be curious to see what your wastegate duty cycle looks like throughout that pull. |
|
|
|
Post by oldschoolmk on Nov 13, 2018 15:10:21 GMT
Have to Minus your regions atmospheric pressure (your mBar at idle) Real Atmospheric pressure can only be measured with your ignition ON, (but engine OFF), with the throttle-body cracked open slightly (you can press the accelerator pedal. That's the value you use for atmospheric pressure in your region. It may be 1,010 or 1,013mBar, etc. Having the engine at idle, is not an acceptable method of measuring atmospheric pressure as your turbine is ALWAYS turning and the compressor generates a tiny bit of boost no matter how minute it may be thus throwing off your subtraction. There is another school of thought that the presence of a boost leak can be discovered by abnormally high wastegate duty cycles. The duty cycle will be low around 1,800 - about say 3,000 RPM, for little to no leaks when going uphill. If your wastegate duty cycle exceeds 80% at any point, you have a problem. When you know you have a problem is when you exceed 80% (stock) wastegate duty at any RPM. It becomes obvious over about 4,500 RPM Edit: I agree with the OP about not having a boost leak. Your graph has the correct shape. I'd be curious to see what your wastegate duty cycle looks like throughout that pull. AWESOME INFO. Thanks! I haven't played with car much lately as I have been spending all free time with family or rebuilding the engine in my 74 beetle. I will check the duty cycle of the Watergate. Any chance you know which number is the Watergate? 114 or 115 is the boost pressure if I remember right. Also there is a odd little buck in the car on w it hits full boost.... (if that's what you want to call it) you can see it in the 4th gear highway pull. It spikes, then drops quickly and finally starts to climb to its actual peak before dropping off again. I am assuming this is the diverter valve? Or could it be my N75 valve. If so is there anyway to reduce that drop? IE manual boost valve before N75 valve to slow its function down without taking boost up. Maybe a smidge over what specified is? |
|
|
|
Post by Matthew on Nov 14, 2018 17:30:02 GMT
|
|
|
|
Post by Matthew on Nov 14, 2018 17:48:25 GMT
If all that you are doing, is holding the car in 4th gear from cruising to redline, then it wouldn't be a diverter valve issue. Torn rubber diverter valves, have a "soft" or low peak boost value, but remains constant (if graphed on the x-axis) until the wastegate opens to prevent damage to the turbocharger. If your car reaches OEM full boost at any point in time, then it isn't a diverter valve issue either, as it is actually sealing properly.
You would be correct in looking at the waste gate next, it may just be a loose actuator, or one that needs to be mechanically adjusted (I'm not an expert at this). In the interim, I'd suggest doing a log of the wastegate in 1st or second gear from above idle to redline. Then finally doing one on 4th gear. The graphs should look the same by comparison other than everything happening faster in the lower gear.
You should NEVER need a manual boost controller unless your car is tuned in some non-standard way with an oversized turbocharger.
The other thing I'd look at is your "fueling" at these Wide OPen Throttle runs in 4th gear to redline. Your fuel pump could not be supplying enough for some reason or another.
|
|
|
|
Post by Matthew on Jan 13, 2019 1:45:56 GMT
I've been plagued with a boost leak somewhere in that my N75 is stuck at 99% duty cycle at anything over ~2,000 RPM. I suspect my issue is my diverter valve. I'll be replacing it with a GFB DV+ in the morning to see it this is the issue. If it turns out to be my wastegate actuator, then I'll be replacing the turbocharger with a F23T in a few weeks when I get it delivered to me.
|
|
