The Project Pad

i've been beating my brain a little trying to figure out a problem with my S6 avant for some time. oh when i bought the car it was stock for starters. the first thing i did was install a boost gauge so i could see what the current boost levels where with the car and i would see 14psi a most and it would bleed down to around 8psi at the top of the RPM. With the current setup listed below and the boost goes above 16psi it seems like the car loses has no power. with the MTM chips i see 19psi at most and when on an average it seems to go to 16psi and bleed down to 10psi at the top of the rev range. when i see boost levels above 16psi is when im crusing and i floor it the car seems to spike up to 19psi and kind of hold there than around 3500 it jumps down to 16psi and starts tapering off to 10psi. the whole time its above 16psi the car feels gutless. i cant think of whats causing this for the life of me, i've ran every option through my head and nothing add's up. well one thing comes to mind when and that the MTM chip has too much timing in the lower RPM range and its making the engine knock which is making it pull timing when it spikes above 16psi. i've driven plenty of cars on the same chip set and they dont seem to act like this at all. all of the other cars didnt have boost gauges so i couldnt see what was going on but they didnt have this slugishness that my car does. anyone have any ideas what it could be? i considered modifying the MTM timing/fuel chip and removing some timing from the map to see it that cures the issue but i feel its not going to.

here's a list of what i've done to it since just for reference.
-custom 3in turbo back exhaust with single muffler and enxternal dump wastegate
-Ebay RS2 turbo manifold
-Custom intake with open element filter
-31x12x3 front mount intercooler with custom piping. piping starts at turbo with stock rubber hose and goes into 2.5in pipe to the intercooler, than from the inercooler to the throttle body is 3in pipe.
-Forge motorsport splitr diverter valve with external vent capped off.
-Custom 1.8T coil pack conversion with NGK BKR7EIX iridium plugs gapped to 24 thousandths.
-ECU has MTM1+ chip set with 034 varimap set to 3bar.

well thats my issue/story, any input on what might be causing this would be great because i know its not running at its full potential.

Here's a few pictures of the engine bay for reference.

For starters, have you pressure tested the intake? After that, try some different plugs, like some FR5DTC's. Detonation could definitely be pulling timing but it sounds like you're having a boost leak also. Some of the clone MTM 1+ stuff is known to ping. Mine did briefly when I would be cruising at 3krpm and stomp it. Also, how old is your fuel filter? If you're losing fuel pressure from an old filter being clogged a bit then leaning out under load/high rpms could also cause issues.

UrSobsessed wrote:For starters, have you pressure tested the intake? After that, try some different plugs, like some FR5DTC's. Detonation could definitely be pulling timing but it sounds like you're having a boost leak also. Some of the clone MTM 1+ stuff is known to ping. Mine did briefly when I would be cruising at 3krpm and stomp it. Also, how old is your fuel filter? If you're losing fuel pressure from an old filter being clogged a bit then leaning out under load/high rpms could also cause issues.

intake is good, all of the gaskets are new as of 2 weeks ago when i installed the powder coated black intake. The black intake is from another AAN engine so its not the original. there was no difference in performance after switching the intake. my boost gauge has vacuum as well and it shows 16 in/hg vacuum at idle which seems normal for an AAN where im at. my 4000 with an AAN swap get the same identical amount of vacuum at idle too. as for plugs it was a ton worse when i was running NGK BKR7E plugs, id have to change them every time i changed the oil pretty much. my friend who has a 550WHP URS4 suggested NGK BKR7EIX iridium plugs because thats what he runs in his at around 30psi. as for the fuel filter i have no idea how old it is, doesnt look horribly old but who knows. i'll have to go get a fresh one and put it on. its probably MTM clone software, i'll have to look at it and see if i can take some timing out of the map to see if that helps.

Good idea on the filter. With the clone pinging, it was obvious. I could hear it loud and clear, especially if driving in a tunnel or next to a wall. As far as a boost leak is concerned, vacuum likely won't tell you whether you have a boost leak. Putting 20psi in the intake plumbing will let you know fast whether there's an issue there. I had a couple of hose clamps that weren't doing the job when I thought I had cranked them down. That being said, the 1+ I had would overboost to ~21psi and taper to about 17. From 5500rpm to redline it would hold ~14psi. That is normal for that software, FWIU. It does sound like you have some kind of wierd spark event going on in there. I looks like the ECU is pulling boost and a lot of timing if the car feels gutless.

If I had a dollar for every customer that gets on my dyno, has low boost and then swears the boost hoses are all good.... You ask if they have pressure tested it and they say, no, but it is good.. an hour later of n75 frustration, yo uusually find a leak

Hank wrote:If I had a dollar for every customer that gets on my dyno, has low boost and then swears the boost hoses are all good.... You ask if they have pressure tested it and they say, no, but it is good.. an hour later of n75 frustration, yo uusually find a leak

truth.

Well, Hank and Marc, sounds like you guys should be charging dollars for boost leaks!

thanks for the input! the clamps and silicone connectors are brand new and i had all the intercooler piping professionally tig welded so i feel its sealed up well. as for your boost levels compared to mine im pretty sure the height above sea level plays a role in how much actual boost output a vehicle will have, correct me if im wrong. im at 997 feet above sea level to be exact. i want to get this sorted our more than ever now because i found and 1.9 and a 2.2 bar wastegate springs in my tool box when i was cleaning it out. as far as it feeling gutless its only when the car goes above 16psi, if i keep it below 16psi and floor it the car pulls super hard tapering down to 10psi. its when im in higher gears like 3rd and up i get that over spike to 19psi and than it will jump down to 16psi bleeding off to 10psi as the RPM's climb. i figured the MTM 1+ was supposed to have more boost than what im seeing because all of the reading i've done people said they would see 20+psi. weird thing is the car acted like this on the stock intercooler too which was the plastic crossover pipe and plastic end tank cooler so i changed all that out for URS4 aluminum crossover pipe and and aluminum intercooler and still same result. i was thinking heat soak because it was pretty hot out at that point in time so i put the 31X12X3 fmic setup on and still the same result even with the cooler temperatures of fall.

Go get a portable air tank, fill it up at the gas station, and test for boost leaks:) seriously, you might be amazed at what you find. It will require making some plugs from pvc a pressure regulator and a few fittings but it's pretty easy.


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Do you have the stock air box? If so..put it back on….AAN and 3B's are weird that way….they don't like CAI filters. Also check the ribs on your MAF to turbo hose…there might be a tear hiding in in the ribs….also check your FPR lines that are rubber…that go to the diaphragm, it might decayed or rotten under the cloth braid.
.02

A20V200 wrote:Do you have the stock air box? If so..put it back on….AAN and 3B's are weird that way….they don't like CAI filters.
.02

Where did you get that idea? This is the kind of misinformation we don't need.

Yes.. unleash the noises from your intake! I think Chris might mean that there are "proper" ways of going CAI and most of us might not have gotten there yet with our renditions. I speak for myself only usually though

The gutlessness at 16 psi kind of sounds like timing retard due to high intake air temp, which could also be a boost leak symptom due to over spinning the turbo. But, have you checked the AIT sensor?

well after pressure testing the intercooler system with 35psi which i made hold for 45 minutes with no pressure loss. than i used a smoke machine to test the piping again along with the intake and any other vacuum lines and came up completely leak free. the IAT sensor seems good as i dont get a CEL from it although i have thought about switching in a 1.8T sensor as i was told its an upgrade. Next step is to get a fuel filter like suggested and install that. i'd like to see with my wideband if thats the problem but its a pain in the ass uninstalling it from my 4000, taking the S6 downpipe off just to weld in another 02 bung and than wiring everything up in the S6. might anyone know if the MTM chips where tuned on 98 octane fuel? the maximum i can get here in PA is 93 octane. just another thought.

The MTM chips should be good with your fuel (93) and FMIC.

Do the fuel filter ASAP and go from there.

well i took a little timing out of the chip and things got better than i finally found the new fuel filter i had laying around and installed it and the car runs like a charm. i got a little curious so i installed the 1.9 BAR spring i had and i get 23psi and it bleeds down to 16psi with that. over all the car runs like a charm! thanks again everyone for the help!