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Discussion Starter · #1 ·
I've noticed something strange recently. When I start the car up it does it's standard idle up at like 1500rpm for a few seconds then drops down under 1000rpm. But i'm also hearing it build boost, hold it for a s2-3 seconds, then release the boost. This is all within 10-12 seconds of startup, sitting still.

Anyone else have this happen? Is it normal and I just didn't notice it the first 138K miles??

I've also been having some inconsistent performance it seems like. Sometimes it feels like the beast it is, other times it seems to have trouble pulling hard. It still goes, but there is what I'd almost call 'lag'.

Mods are listed in my signature. I'll be installing IPD's TCV, a Forge CBV, and a new Boost Sensor tonight.
 

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I've come to think that this T5 engine is very temperamental. And I have 7 years of driving with it. It varies greatly depending on outside ambient temperature, humidity in the air, rain conditions, engine temperature conditions (how long it sat in the cold or heat for that matter) , fuel quality or mix, etc... etc...
I get the same thing. However on long trips it always seems to stabilize and runs better once all has got to proper functioning temperature. I guess that's to be expected. But I agree that on a daily basis it's a bit all over the place IMO.

And FYI it should run at higher rpms for about 30 or more seconds until parts heats up. Then go back to idle. But I did not think it builds boost though... Just runs higher so the turbo warms up.
 

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Discussion Starter · #3 ·
Agreed about it being moody. I've had mine 7 years as well, and it can be all over the place. I should have mentioned it's been 90-105 degrees around here and very humid (gotta love DC...:rolleyes:) so I expect some performance decrease. It was really the boost building that caught my ear...seemed weird.

And you're right TG, it's more like 30 seconds that it idles higher, so no worries there.

In other news I have a wonderful click-click-pop-pop noise when turning sharply at slow speeds...bye bye CV joint...:thumbdown:
 

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I hate these P1 CV joints. I can't believe how many people have had problems with them! For the cost they should be able to do a lot better!!! You can buy much less expensive cars with much fewer CV joints problems. Maybe it has to do with the suspension not agreeing with it...
 

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-Matt- 2005 S40 T5 AWD 6SPD
Autotech Stg3, ATP FMIC, Injen Intake, Elevate DP & Exhaust, SNAAB STS, IPD Coilpacks, Elevate Torque Mount, KW V1's, IPD Endlinks, Elevate Rear Sway Bar, Powerflex Bushings
Are you sure that you're hearing actual boost, like you see it in a boost gauge? Otherwise I'm pretty sure you hear what I hear, just the turbo spinning. It should be in vacuum still. But because you have an open exhaust, you can listen to the turbo spinning better. I have a straight pipe axle back and I hear the same thing on warm up.

It is extemely difficult and hard on the engine to actually build boost without load on the engine e.g. in neutral or at a stop. It requires a launch control system or two-step system (can't remember which one is which). The concept is to load up the engine on fuel (very rich) and retard the ignition timing like hell causing the AF mixture to ignite in the cylinder and partially in the exhaust. It basically turns your exhaust manifold into the combustion chamber. This spins the turbo enough to build boost at a stand still and destroys your turbo in the name of immense fun (something I can get behind).

So I doubt that it is actually creating boost or pressure in that state, it really takes a lot.

(Has anyone done a two-step or lauch control on their S40?)
 

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Discussion Starter · #6 ·
Are you sure that you're hearing actual boost, like you see it in a boost gauge? Otherwise I'm pretty sure you hear what I hear, just the turbo spinning. It should be in vacuum still. But because you have an open exhaust, you can listen to the turbo spinning better. I have a straight pipe axle back and I hear the same thing on warm up.
Its just the turbo...I must have been inhaling exhaust fumes when I thought it was boost. The S40 has just been a little weird last couple months so little things that are probably nothing I seem to give too much attention to. Thanks.
 

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Its just the turbo...I must have been inhaling exhaust fumes when I thought it was boost. The S40 has just been a little weird last couple months so little things that are probably nothing I seem to give too much attention to. Thanks.
I've been there too many time with this car :p . . . Lol, probably the worse part of it.
 

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little things that are probably nothing I seem to give too much attention to. Thanks.
I know what ya mean, I went a little overboard on the response...
 
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