Boost fade

[1ViciousGSX]

but most good front mounts are semi restrictive. the air has to bump into something to transfer the heat.
But not that restrictive. ;)

[Pushit2.0]

Most side to side FMIC will produce 1-2 psi pressure drop. The turbo spits out hot air then you cool that air off and it becomes more dense, thus would have less pressure, or atleast thats my take on it.

~John

[asshanson]

Alright, here is a more complete list of mods:

crushed 1g BOV (didn't leak up to 20 lbs in my tests, i went to 25 lbs could only hear the BOV hissing)
650 injectors
190 walbro fuel pump
Greddy 24R FMIC kit and the few pipes it comes with to hook up to stock piping
Dejon intake and upper intercooler pipes (2.25" I think)
Ractive (?) air filter
17 lb actuator from FP, not the 11lb it came with. I thought this was the issue originally and it didn't help much.

Relevant Stock parts:

lower intercooler braided hose
braided hose from BOV to TB elbow

[Kracka]

Get a real K&N or AFE air filter, those cheap generic cotton-gauze filters have been proven to flow much less than the quality brand name ones.

[asshanson]

I always wondered if this was a big deal or not. The previous owner had it on there and I never got around to changing it, even after it fell apart and I had to glue it together again. Haha, I'll let you know if this helps in a week or two or whenever the filter arrives and gets installed.

[Jakey]

Get a real K&N or AFE air filter, those cheap generic cotton-gauze filters have been proven to flow much less than the quality brand name ones.

Not only do they flow less, but depending on the amount of air you are trying to pull throught a filter, you can cause it to collapse and potentially fall apart, especially with those piece of shit off-brand filters.

[Pushit2.0]

Or the big HK$ foam things that always end up in the turbo. I would look at your boost controller and how its routed.

~John

[asshanson]

Here's what I did: took off the filter, cleaned it, ran a few passes WITHOUT the filter on, same thing happened. Faded to just under 15 lbs by 6500 rpm.

Maybe my wastegate sucks.

[asshanson]

I did more tests the other day, here is what I've gathered:

boost controller was hooked up to turbo as pressure source, probably 12" of hose to turbo and 12" to wastegate.

I changed the pressure source to be the intake manifold, didn't help.

I lowered the boost one full turn on the controller. Nothing really changed except it made 17lbs and faded to 14. Weird.

I upped the boost two full turns, it made uncontrollable boost, instantly went to 25 lbs so I let off completely. Then I did a pull and controlled the throttle so it made 18 lbs, maybe 50% or 60% throttle, held solid to over 7k rpms.

The HZ on the AFC read something like 2400, I usually max out around 1700. This makes sense though (I think) because with the throttle body partially open, there would have been higher pressure in the pipes than the intake manifold, and the ssqv bov opened because I heard a high pitch airy sound past 5k rpms. So it was measuring more air than was getting to my engine, which is why it was so high probably.

Then I put it back to 1/8 turn over the original value, now it spikes to 19psi, then fades to 15 or 16.

So to me it seems like the boost is coming on too quickly and the boost controller can't keep it under control, takes 2k rpm to settle to where it should be. Could this be a wastegate problem?

[Kracka]

Sounds to me like your MBC should be set somewhere between where it started and the two full turns. What happens with just one turn up? Did you route the MBC back to how it was before (turbo-MBC-WG)? That routing will help control spike.