Determining an intake restriction on a boosted setup from logs
09-18-2019, 08:38 PM
#1
Determining an intake restriction on a boosted setup from logs Listing some of the main guys on here who tune so I can get some input...
@turbolx @joecar @ChopperDoc @JoeNova @SLOW SEDAN
On an NA car it's very straightforward to tell from a log if you have an intake restriction. How do you do this on a boosted car, SPECIFICALLY when there is a boost curve and not a set boost pressure, but highly varies over the RPM range? Had a question from a member on another forum who said a shop told him he had an intake restriction on his boosted car from remotely looking at a log, curious how they were able to do this.
@turbolx @joecar @ChopperDoc @JoeNova @SLOW SEDAN
On an NA car it's very straightforward to tell from a log if you have an intake restriction. How do you do this on a boosted car, SPECIFICALLY when there is a boost curve and not a set boost pressure, but highly varies over the RPM range? Had a question from a member on another forum who said a shop told him he had an intake restriction on his boosted car from remotely looking at a log, curious how they were able to do this.
09-19-2019, 01:03 AM
#2
TECH Senior Member
I would think that TOO HIGH a boost pressure for the indicated power would be a sign of a restriction. This would indicate pressure buildup(or backpressure, if you will) in the intake tract.
This is speculation on my part.
This is speculation on my part.
09-19-2019, 07:33 AM
#5
Restricted User
What part of the intake are we talking here? Pre turbo or post?
Pre turbo restrictions in the filter will show as vacuum.
Post turbo will show as pressure drop after the restriction.
Pre turbo restrictions in the filter will show as vacuum.
Post turbo will show as pressure drop after the restriction.
09-19-2019, 10:20 AM
#7
Launching!
Easy, put a pressure sensor at the compressor inlet. Anything less than barometric pressure means some loss in the inlet system. This works for Centifgual/Turbo/Positive Displacement. You just want the most available pressure (at a cool temperature) entering the compressor as is possible. Compressors are surprisingly good at pushing through restrictions (intercooler bricks, intake valves, manifolds, blow-through throttle bodies, etc) but struggle to pull through a restriction (undersized inlet pipes, tight bends, draw-through throttle bodies, etc).
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09-19-2019, 12:07 PM
#10
If the MAF is pre turbo and you have a restricted filter I could see the reading being off from what is "normal" with a higher flowing setup. Kinda like when LSA guys go to a 5" intake setup, MAF readings change and lower restriction to the blower snout.
09-19-2019, 04:33 PM
#14
Restricted User
If the intake tube where the MAF is at has any bends, reducers, or filter at the MAF, itll be a pain in the *** to tune because of the awkward flow path. Maybe that's the restriction they are talking about causing the lackluster results?
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Stokes1114 (09-19-2019)
09-19-2019, 04:45 PM
#15
This is an OEM setup that is a draw through maf twinturbo. Factory cold air intake on the turbos but the vendor says the aftermarket cold air intake is a restriction vs stock....I think based on all of you guys posts confirming what I was thinking....it's BS lol.
09-19-2019, 06:33 PM
#16
Restricted User
If it was a remote tune this it is them blowing smoke. Any of the things that would cause a pre turbo restriction would either need visual inspection, physical trial and error, or extra sensors to verify.
09-20-2019, 04:55 AM
#18
TECH Fanatic
I was trying not to overthink this, as I figured there might be a way to calculate it with some serious math, but I must admit I failed lol. I totally started overthinking this. However, without the data in the first place, it's just not possible considering all the factors. It's pretty simple. There's no way to calculate this remotely without additional sensors, or a comparison log of the same car in different configurations. Just too many things to account for when it comes to airmass, like heat, pressure, baro, flow, etc. The physics of this are not exactly simple.
Pretty sure the shop is full of **** here. We might as well start analyzing random logs people post on here to see if they have air restrictions. Practically impossible if additional sensors are not used and logged. That and I'm pretty sure most shops just aren't going to take the time to crunch all the numbers and put that much time into a remote tune. And even if so, what numbers exactly could you use to tell if you are using stock parameters? There's just not enough information to come to a reliable conclusion.
Pretty sure the shop is full of **** here. We might as well start analyzing random logs people post on here to see if they have air restrictions. Practically impossible if additional sensors are not used and logged. That and I'm pretty sure most shops just aren't going to take the time to crunch all the numbers and put that much time into a remote tune. And even if so, what numbers exactly could you use to tell if you are using stock parameters? There's just not enough information to come to a reliable conclusion.
10-08-2019, 08:30 AM
#20
TECH Addict
only way i could figure they would know without more sensors or seeing it in person would be if they are VERY familiar with the platform and know that a specific combo 'should' perform a certain way. Theres a few guys in the evo world i bet could identify something similar to what you are describing.