High WGDC

The Ghost · 07-21-2012, 01:35 AM

My car has a decent boost curve, able to hit 18.x psi, however the boost will start tapering past 4500rpms. At 5500rpms WGDC is already at 9x%. Looking at others' log, most have WGDC in the 60's. Car is FBO, stock exhaust. Intercooler is Helix FWIW.

Attached are a few logs.

Thanks,

-TG

BMWsky · 07-21-2012, 10:38 AM

Your fuel trims aren't horrible, but seem on the high side for where everything else is. What is your OL at? Are you running the pump gas maps or E85?

I would think that if you've got a boost leak, you'd throw a code as your car wouldn't be able to hit the requested boost.

M3 Eater · 07-21-2012, 10:51 AM

Mine is up to 118. It happens. check all vac lines.

rader1 · 07-21-2012, 11:22 AM

Can you attach a txt copy of the csv?

Joshboody · 07-21-2012, 11:30 AM

Log boost setpoint on the boost gragh and wgdc sepatately. Looks to be a vac line issue. Check all your piping also of course. Let us know what you find.

The Ghost · 07-21-2012, 05:19 PM

Quote:

Originally Posted by Joshboody

Log boost setpoint on the boost gragh and wgdc sepatately. Looks to be a vac line issue. Check all your piping also of course. Let us know what you find.

Boost set point is 18psi until 6k, so it's not meeting this just beyond 4500rpms. Fuel is 50/50 e85/93.

I'm going to do a pressure test tonight.

Is anyone else seeing high values similar to mine?

The Ghost · 07-22-2012, 04:40 PM

I did a pressure test and front BOV was leaking at the chargepipe coupler. The o-ring was bent and out of shape. Luckily I have a spare chargepipe, so I replaced the o-ring which fixed it.

The leak was not HUGE, but there and really obvious. The WGDC still climbs to the same peak, but does so more slowly and doesn't flatline. Boost curve is about the same, albeit slightly more flat.

I believe I'm getting more air because I actually logged a knock event, which I hadn't before. Attached is a log.

Tzu · 07-23-2012, 07:05 AM

Can you put WGDC on its own graph? It looks to be 48ish climbing to 60, which isnt terrible but can be indicitive of a small leak.

The Ghost · 07-23-2012, 08:02 AM

It is 40's ramping to 99.9%. Revs in the above log go to 6200rpms.

Tzu · 07-23-2012, 09:17 AM

Yea thats a problem. Could be a leak but if it was a consistant leak then I dont think youd be able to sustain 40ish WGDC at 18psi even in the midrange. Can you pull vacuum from all the lines with the car off and see if it can hold any? If you dont have a vacuum source, drive around a bit and pull off the line for the brake booster by the oil filter housing after 5mins, you should still hear a significant sound as air rushes in.

The Ghost · 07-23-2012, 10:31 AM

I pressurized the entire system from the intercooler hotside forward to 25psi with no leaks (outside of the one I fixed), so there isn't a leak. The only possible leak is at the couplers between turbos and IC, as that can't be tested using the above method.

When you think about it, assuming my boost curve above 5k rpms is the max possible, then te WGDC should max out.

07-21-2012, 01:35 AM	#1
The Ghost Reborn 87 Rep 1,217 Posts Drives: 335i Join Date: Jun 2011 Location: USA iTrader: (1)	High WGDC - Possible Boost Leak? My car has a decent boost curve, able to hit 18.x psi, however the boost will start tapering past 4500rpms. At 5500rpms WGDC is already at 9x%. Looking at others' log, most have WGDC in the 60's. Car is FBO, stock exhaust. Intercooler is Helix FWIW. Attached are a few logs. Thanks, -TG Attached Images
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07-21-2012, 10:38 AM	#2
BMWsky Major 25 Rep 1,244 Posts Drives: 335i Join Date: Dec 2010 Location: Webster NY iTrader: (1)	Your fuel trims aren't horrible, but seem on the high side for where everything else is. What is your OL at? Are you running the pump gas maps or E85? I would think that if you've got a boost leak, you'd throw a code as your car wouldn't be able to hit the requested boost.
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07-21-2012, 10:51 AM	#3
M3 Eater Major 36 Rep 1,054 Posts Drives: 335i Sedan Join Date: May 2010 Location: Unknown iTrader: (3) Garage List 2007 335i [0.00]	Mine is up to 118. It happens. check all vac lines. __________________ JB4 beta 15 ohms FSB,AEM inline filter/ CM 10, ETS fmic, ER custom made charge pipe,TSW Donnington 18's,Simitumo HTRZ3, Injen DCI, AR DPs, Forge DVs, AA SLD, Koni FSD, ZSP springs.
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07-21-2012, 11:22 AM	#4
rader1 Banned 70 Rep 2,197 Posts Drives: Cobb Stage 2+ 135i Join Date: Apr 2011 Location: Roanoke, VA iTrader: (0)	Can you attach a txt copy of the csv?
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07-21-2012, 11:30 AM	#5
Joshboody Lieutenant Colonel 65 Rep 1,708 Posts Drives: pickemuptruck Join Date: Jul 2009 Location: Phoenix, AZ iTrader: (7)	Log boost setpoint on the boost gragh and wgdc sepatately. Looks to be a vac line issue. Check all your piping also of course. Let us know what you find.
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07-22-2012, 04:40 PM	#7
The Ghost Reborn 87 Rep 1,217 Posts Drives: 335i Join Date: Jun 2011 Location: USA iTrader: (1)	I did a pressure test and front BOV was leaking at the chargepipe coupler. The o-ring was bent and out of shape. Luckily I have a spare chargepipe, so I replaced the o-ring which fixed it. The leak was not HUGE, but there and really obvious. The WGDC still climbs to the same peak, but does so more slowly and doesn't flatline. Boost curve is about the same, albeit slightly more flat. I believe I'm getting more air because I actually logged a knock event, which I hadn't before. Attached is a log. Attached Images
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07-23-2012, 07:05 AM	#8
Tzu Lieutenant Colonel 29 Rep 1,551 Posts Drives: 335i Join Date: Jun 2010 Location: Toronto iTrader: (1)	Can you put WGDC on its own graph? It looks to be 48ish climbing to 60, which isnt terrible but can be indicitive of a small leak.
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07-23-2012, 08:02 AM	#9
The Ghost Reborn 87 Rep 1,217 Posts Drives: 335i Join Date: Jun 2011 Location: USA iTrader: (1)	It is 40's ramping to 99.9%. Revs in the above log go to 6200rpms.
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07-23-2012, 09:17 AM	#10
Tzu Lieutenant Colonel 29 Rep 1,551 Posts Drives: 335i Join Date: Jun 2010 Location: Toronto iTrader: (1)	Yea thats a problem. Could be a leak but if it was a consistant leak then I dont think youd be able to sustain 40ish WGDC at 18psi even in the midrange. Can you pull vacuum from all the lines with the car off and see if it can hold any? If you dont have a vacuum source, drive around a bit and pull off the line for the brake booster by the oil filter housing after 5mins, you should still hear a significant sound as air rushes in.
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07-23-2012, 10:31 AM	#11
The Ghost Reborn 87 Rep 1,217 Posts Drives: 335i Join Date: Jun 2011 Location: USA iTrader: (1)	I pressurized the entire system from the intercooler hotside forward to 25psi with no leaks (outside of the one I fixed), so there isn't a leak. The only possible leak is at the couplers between turbos and IC, as that can't be tested using the above method. When you think about it, assuming my boost curve above 5k rpms is the max possible, then te WGDC should max out.
	Appreciate 0 Quote