Will the turbos overspool when you have a boost leak ?

e.n335 · 07-14-2008, 02:41 PM

Hi,

I installed my Spearco FMIC today

. It was a PITA. Beside the normal trimming I had to modify the FMIC to make it fit. Do you have different cars in the US ?. One of quite some things I had to do is to cut off 1 inch of the outlet pipe to make some space for a cooling related device down there.

Now, at my first test I had a boost leak ( nothing unexpected with my cutted outlet pipe and the delivered hoses ). In my 4 cases the engine went to limp-mode at ~ 8 psi and sounded very metallic.

I fixed the leak now everything works great and I already ordered different hoses to fix the issue sustainable.

The turbos made still ~ 8 psi in limp-mode with the boost leak. Now, did the turbos overspool ?

Thanks,
Eugen

Kbueno · 07-14-2008, 03:04 PM

Not sure if they over-spooled...but they had to constantly spool to maintain the 8psi. This will definitely wear out your turbos over an extended amount of time. Always a good thing to check for boost leaks.

Park2670 · 07-14-2008, 03:18 PM

Right after I installed my boost gauge I was seeing some overboosting as the car was trying to meet the certain targets. So I would say its certainly possible with a tune to overboost and with a leak. Stock, I think the DME would notice something is up.

e.n335 · 07-14-2008, 03:24 PM

There has not been something disconnected in the tubing. It seems to me the leak did not sustain + 8 psi and so the car limped. However, even in limp-mode it made + 8 psi. In that situation the engine sounded very metallic and behaved like stock.

e.n335 · 07-14-2008, 03:32 PM

BTW, with all the issues, I would take the Spearco again. Great improved throttle and turbos response, the engine runs a bit cooler and the car feels faster. No changes on the Noelle ECU flash.

I'll install it sustainable using new hoses ând find a final solution for the cooling device down there and will re-dyno the car on the same dyno.

Wow !!!

Sniz · 07-14-2008, 03:33 PM

I had the same issue when I put in my intercooler last year. One of the intercooler pipes popped off when I went WOT. The car made a ridiculous noise and went limp. The noise is most likely all the air rushing out of the leak...also keep in mind the pressurized air is all after the turbo's...so the turbo noise will be loudest there.

e.n335 · 07-14-2008, 03:44 PM

Quote:

Originally Posted by Sniz

I had the same issue when I put in my intercooler last year. One of the intercooler pipes popped off when I went WOT. The car made a ridiculous noise and went limp. The noise is most likely all the air rushing out of the leak...also keep in mind the pressurized air is all after the turbo's...so the turbo noise will be loudest there.

Thanks. The noise has been strange.

Mr. 5 · 07-14-2008, 04:06 PM

Strange because I thought that the Spearco ICs were supposed to be asy to install.
I put in the AA IC and it was very straight forward.

Sniz · 07-14-2008, 04:24 PM

e93 might be different??

Kbueno · 07-14-2008, 04:32 PM

Quote:

Originally Posted by Park2670

Right after I installed my boost gauge I was seeing some overboosting as the car was trying to meet the certain targets. So I would say its certainly possible with a tune to overboost and with a leak. Stock, I think the DME would notice something is up.

Depends on the severity of the leak, it may not be enough to throw a code. Sniz indicated you could drop the plastic engine bay bottom and hook up a boost leak tester.

As for the boost gauge: I've read that if there is a leak, you'll see the pressure rise to your target and then slowly fall and then rise back up again?? What did you overboost behavior look like?

hotrod182 · 07-14-2008, 04:34 PM

The turbos should spool faster at any given pressure with a boost leak, at least until it goes into limp mode.

CASHBY · 07-14-2008, 04:47 PM

usually with a boost leak it will hit your target PSI but it will taper back down pretty quick. So if your not holding the target PSI then you might have a leak.

Also with a big enough boost leak you will for sure hear it leaking.

StarrDlux · 07-14-2008, 07:35 PM

when the turbo needs to reach 250K rpm's to meet desired boost the IAT's will be out of this world plus you'd hear the turbo's screaming.

less mass air density and same boost. surging is very likely too at high rpm's where the turbo can no longer meet requested boost. you'd hear it all right but i'm not sure without some sort of mass air device you'd be able to measure it accurately.

a small leak may be as inefficient as a 90F day in denver (elevation).

bust out the smoke machine

and pressurize the system to 18-20psi : thats how most other turbo manufacturers look for leaks.

On my old old vw i would throw some UV dye in the boost tubes and oil and throw a UV (eprom eraser) light on after a few days and boom yellow glowing all over (coupling leaks, valve cover gasket). car has 150K on it so i wasn't suprised.

you ever take the boost tubes off to see how much oil the n54 eats?

Digital.James · 07-14-2008, 08:47 PM

My Spearco went in without a hitch, very easy. Only modification was the 1/4" trim from the black bumper support.

I had one of my charge pipes fall off as well right after the install. Car sounded kind of wheezy and then limp.

07-14-2008, 02:41 PM	#1
e.n335 Moderator 279 Rep 4,481 Posts Drives: e93 ///M3 DCT, 07/2009 Join Date: Feb 2007 Location: Switzerland, ZH iTrader: (0)	Will the turbos overspool when you have a boost leak ? Hi, I installed my Spearco FMIC today . It was a PITA. Beside the normal trimming I had to modify the FMIC to make it fit. Do you have different cars in the US ?. One of quite some things I had to do is to cut off 1 inch of the outlet pipe to make some space for a cooling related device down there. Now, at my first test I had a boost leak ( nothing unexpected with my cutted outlet pipe and the delivered hoses ). In my 4 cases the engine went to limp-mode at ~ 8 psi and sounded very metallic. I fixed the leak now everything works great and I already ordered different hoses to fix the issue sustainable. The turbos made still ~ 8 psi in limp-mode with the boost leak. Now, did the turbos overspool ? Thanks, Eugen
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07-14-2008, 03:04 PM	#2
Kbueno Lieutenant Colonel 101 Rep 1,712 Posts Drives: F82 Join Date: Jan 2007 Location: California iTrader: (5)	Not sure if they over-spooled...but they had to constantly spool to maintain the 8psi. This will definitely wear out your turbos over an extended amount of time. Always a good thing to check for boost leaks.
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07-14-2008, 03:18 PM	#3
Park2670 General 361 Rep 18,218 Posts Drives: Tesla Model 3 Join Date: Jan 2006 Location: UTAH iTrader: (8)	Right after I installed my boost gauge I was seeing some overboosting as the car was trying to meet the certain targets. So I would say its certainly possible with a tune to overboost and with a leak. Stock, I think the DME would notice something is up. __________________
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07-14-2008, 03:24 PM	#4
e.n335 Moderator 279 Rep 4,481 Posts Drives: e93 ///M3 DCT, 07/2009 Join Date: Feb 2007 Location: Switzerland, ZH iTrader: (0)	There has not been something disconnected in the tubing. It seems to me the leak did not sustain + 8 psi and so the car limped. However, even in limp-mode it made + 8 psi. In that situation the engine sounded very metallic and behaved like stock.
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07-14-2008, 03:32 PM	#5
e.n335 Moderator 279 Rep 4,481 Posts Drives: e93 ///M3 DCT, 07/2009 Join Date: Feb 2007 Location: Switzerland, ZH iTrader: (0)	BTW, with all the issues, I would take the Spearco again. Great improved throttle and turbos response, the engine runs a bit cooler and the car feels faster. No changes on the Noelle ECU flash. I'll install it sustainable using new hoses ând find a final solution for the cooling device down there and will re-dyno the car on the same dyno. Wow !!!
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07-14-2008, 03:33 PM	#6
Sniz Lieutenant General 680 Rep 10,584 Posts Drives: e92 335 - gone // e36 M3 turbo Join Date: Mar 2007 Location: Ellicott City, MD iTrader: (1)	I had the same issue when I put in my intercooler last year. One of the intercooler pipes popped off when I went WOT. The car made a ridiculous noise and went limp. The noise is most likely all the air rushing out of the leak...also keep in mind the pressurized air is all after the turbo's...so the turbo noise will be loudest there. __________________
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07-14-2008, 04:06 PM	#8
Mr. 5 Modder Raider 800 Rep 8,633 Posts Drives: M3 Join Date: Apr 2007 Location: Surf City, HB iTrader: (31) Garage List 2007 e90 335i [8.00]	Strange because I thought that the Spearco ICs were supposed to be asy to install. I put in the AA IC and it was very straight forward. __________________ e36 M3 Coupe, e36 325i Sedan e90 335i--SOLD Best 60-130-------------9.15 Seconds------------------WWW.MR5RACING.COM
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07-14-2008, 04:24 PM	#9
Sniz Lieutenant General 680 Rep 10,584 Posts Drives: e92 335 - gone // e36 M3 turbo Join Date: Mar 2007 Location: Ellicott City, MD iTrader: (1)	e93 might be different?? __________________
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07-14-2008, 04:34 PM	#11
hotrod182 . 878 Rep 3,994 Posts Drives: 2023 i4 M50 Join Date: Dec 2006 Location: California iTrader: (0)	The turbos should spool faster at any given pressure with a boost leak, at least until it goes into limp mode. __________________ 2011 Alpine 335d M-Sport 12.34 @ 110.48mph 2019 i3s Terra, 2008 Black 335i Sedan. 11.11@ 129.47 mph 2008 Monaco Blue JB3 2.0 335i Coupe. 11.33 @ 132.77 mph, 60-130mph: 6.95 seconds 2023 i4 M50 11.48 @ 121.56mph, 3.43 0-60 (dragy)
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07-14-2008, 04:47 PM	#12
CASHBY 171 Rep 2,114 Posts Drives: E90 335 "done up" Join Date: Dec 2006 Location: GARAGE iTrader: (2)	usually with a boost leak it will hit your target PSI but it will taper back down pretty quick. So if your not holding the target PSI then you might have a leak. Also with a big enough boost leak you will for sure hear it leaking.
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07-14-2008, 07:35 PM	#13
StarrDlux Pussycat's Meow 9 Rep 682 Posts Drives: '08 335i montego \| Stock Join Date: May 2008 Location: Midtown (Altanta) iTrader: (0)	when the turbo needs to reach 250K rpm's to meet desired boost the IAT's will be out of this world plus you'd hear the turbo's screaming. less mass air density and same boost. surging is very likely too at high rpm's where the turbo can no longer meet requested boost. you'd hear it all right but i'm not sure without some sort of mass air device you'd be able to measure it accurately. a small leak may be as inefficient as a 90F day in denver (elevation). bust out the smoke machine and pressurize the system to 18-20psi : thats how most other turbo manufacturers look for leaks. On my old old vw i would throw some UV dye in the boost tubes and oil and throw a UV (eprom eraser) light on after a few days and boom yellow glowing all over (coupling leaks, valve cover gasket). car has 150K on it so i wasn't suprised. you ever take the boost tubes off to see how much oil the n54 eats? __________________ 2008 335i montego \| stock 2002 A4 1.8TQS \| APR 1+ 1990 VW Corrado \| Stage 4 by SNS
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07-14-2008, 08:47 PM	#14
Digital.James Colonel 125 Rep 2,702 Posts Drives: GT4, Raptor.2, Tuono 1100F Join Date: Sep 2007 Location: NC iTrader: (7)	My Spearco went in without a hitch, very easy. Only modification was the 1/4" trim from the black bumper support. I had one of my charge pipes fall off as well right after the install. Car sounded kind of wheezy and then limp.
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