Weird noise at high RPM & boost

zaxrex · Post by **zaxrex** » Fri Sep 09, 2005 2:21 pm

Things haven't been as "sporty" as I had them a few weeks back. I figured It was just the anticipation of the FMIC that was half installed.

Last night I was coming back from DC and heard hissing/whistling coming from the engine bay at high RPM and boost followed by a reduciton in boost by about 2-3 psi. I figured I had a leak somewhere so I park at home and pull up the hood. Nothing looked loose or worked off of any hose clamps, but I did notice that the water line going to the Aquamist pump was whiter than usual. I pulled it out to inspect it and I saw NO WATER.

There had been a hole worn away on the nylon tubing. I had wrapped it around the NYLON overflow tank before the FMIC, and around the METAL one since them. The metal had vibrations slowly had ground away the material and the pump was not pumping any water. I had no knock even while running the TurboXS tuned map and my ignition advance crazy map... engine no go boom like avatar

I think over the years I have just gradually beat on the engine to the point that it is now in total submission and compliance.

Post by **complacent** » Fri Sep 09, 2005 3:04 pm

Sounds like either

a) The FMIC is doing exactly what it's supposed to

or

b) Your motor has teh tame and is now your own personal gimp...Responds to any/all your wishes/needs without complaint.

That is interesting to hear though... I wonder if the cooler charge the FMIC provides is at least close to equal to the amount of cooling the WI provides. hmmmm...

zaxrex · Post by **zaxrex** » Fri Sep 09, 2005 3:53 pm

The FMIC core is mounted but NO PIPES installed. Still running the stoc TMIC.

Mr Kleen · Post by **Mr Kleen** » Fri Sep 09, 2005 3:55 pm

^^^--- so much for Colin trying to rationalize a FMIC for the STi!

drwrx · Post by **drwrx** » Fri Sep 09, 2005 4:02 pm

This is just crazy! How much boost were you running and at what RPM?
While the engine didn't go boom is a bit of a surprise, the fact that you got NO knock indication (either from the UTEC or your Knock Link) is simply amazing!

The FMIC can't be the reason. Cool intake temps aside, you have massive timing advance with a crazy high AFR. Are you sure you were pushing no water/ethanol at all?

Trust me, cold, dence air creates it's own problems. If anything a significantly cooler charge can cause some serious lean spots in the rev band. On a 70-80 degree day with 60-70% humidity that is a great thing. At 30 degrees with 20% humidity it is a recipe for knock.

You guys with FMICs probably will never have this issue in winter since the extra feet of pipes that pass through the engine bay will always warm and equalize the intake charge a bit. Not so with a big TMIC. Tip-in to the trottle at 40 mph and jump from no boost to 18lbs rushing through the IC that is only a matter of inches from the intake manifold and suddenly a huge charge of cold dense air enters the combustion chamber and your O2 sensor is overpowered, as you get a 10-12 count knock event and your ECU scrambles to pull timing.

zaxrex · Post by **zaxrex** » Fri Sep 09, 2005 5:52 pm

I was running 18 psi and 1400F. Had the WI been working (the tube was bone dry from the resevoir down to the hole and to the pump), the map should have been around 12:1 AFR. That has to be adjusted a little bit since the pump was dry, the whistling I heard was the air pushing the piston down to the intake inlet and escaping out through the water supply line. Bud I doubt that that little air would cause much of an AFR change.

I think the thing that saved my ass was that I ws running my ethanol mix which has changed the long term and short term fuel trims to add a lot more fuel. My effective octane in the fuel sould be around 96.

BTW the FMIC core has the end tanks covered with dict tape to keep dust & stuff from getting in untill I put the intake on and can install the pipes.

Post by **complacent** » Fri Sep 09, 2005 9:58 pm

?????????

WTF??!?!?!

Wow, that's impressive. I know I wouldn't have been that lucky. Can't wait to see what's going to happen once you plumb the whole thing in...

Post by **complacent** » Fri Sep 09, 2005 10:00 pm

Mr Kleen wrote:^^^--- so much for Colin trying to rationalize a FMIC for the STi!

too late

check out my thread in teh vendor section... I am well on my way to trouble with this car. heh heh.

<jedi mind tricks>You NEED an FMIC</jedi mind tricks>

One of these days I'm going to add up receipts and cry about it. Till then...

Mr Kleen · Post by **Mr Kleen** » Sat Sep 10, 2005 2:31 am

hey, if you have to stop and add it up to feel bad then you haven't gone far enough!

but seriously, with "only" the Accessport, DP and home baked intake I can get into way too much trouble. and I still have the UP to install. this car won't see a turbo swap while I'm still paying for it. it's already stupid fast. once I get my UP and springs installed I will only "need" a mid pipe and rear sway bar and she's finished. then I start spending money on track days again...

ldstang50 · Post by **ldstang50** » Wed Dec 21, 2005 2:22 pm

have you even tried a boost leak test? only way to really tell if you have a leak is to try it.
I dont' know what other mods you have, but if you are still running a stock turbo, the extra long piping you have now can cause some boost tapper at high rpms as the turbo starts to 'run out.' Atleast thats what happens in my car

Post by **Sabre** » Wed Dec 21, 2005 3:02 pm

Definitely come to a meet ldstang, if nothing else just to check out Zak's car... don't be fooled by it's looks (very plain looking).

Mr Kleen · Post by **Mr Kleen** » Wed Dec 21, 2005 3:15 pm

sabre wrote:Definitely come to a meet ldstang, if nothing else just to check out Zak's car... don't be fooled by it's looks (very plain looking).

and just a little dusty...

ldstang50 · Post by **ldstang50** » Wed Dec 21, 2005 4:12 pm

sabre wrote:Definitely come to a meet ldstang, if nothing else just to check out Zak's car... don't be fooled by it's looks (very plain looking).

i wont' be able to make a meet till after the first of the year. but i'll be at one! i think we all agree, understated is the way to go

Mr Kleen · Post by **Mr Kleen** » Wed Dec 21, 2005 4:18 pm

under promise, over deliver

Post by **Sabre** » Wed Dec 21, 2005 4:27 pm

I keep mine as quiet and as stock looking as possible as well. I wish the wing wasn't stock, but I'm not going to take it off either, haha.

zaxrex · Post by **zaxrex** » Wed Dec 21, 2005 4:35 pm

That aint dust, that's camouflage! Urban obscuration. Tactical deception. Me being a lazy ass... call it what you will.

Parking next to Julian just makes his car look that much better!

Post by **Sabre** » Wed Dec 21, 2005 5:08 pm

zaxrex wrote: Parking next to Julian just makes his car look that much better!

W00t

The neighbors think the STI is cloning itself slowly...

ldstang50 · Post by **ldstang50** » Wed Dec 21, 2005 5:24 pm

sabre wrote:I keep mine as quiet and as stock looking as possible as well. I wish the wing wasn't stock, but I'm not going to take it off either, haha.

since every evo out there is running around with an exhaust, i'm not worried about that. plus not having a cat, resonator or muffler makes it sound great!

Mr Kleen wrote:under promise, over deliver

i like that

as far as looks go, i have an intake, upper i/c and exhaust, but what evo doesn't??