APS misquotes max efficient boost for TD04?
01-27-2003, 07:03 PM
#1
@Stoptech
Thread Starter
iTrader: (5)
Join Date: Nov 2002
Location: San Francisco, CA
Posts: 2,416
Car Info: 2002 WRX Wagon
APS misquotes max efficient boost for TD04?
I was browsing the APS website and came across their statement that:
"Typical of any turbocharger, as boost pressure is increased past the point where peak air flow [on the TD04] is produced (at around 19 psi of boost pressure), air flow, hence horsepower decreases."
Did the ADM WRXs get a different TD04 than our TD04L? If not, how do they figure that this turbo's maximum efficient boost if near 19 PSI when it is common belief on this board that one should not run more than 16 PSI on the stock turbo?
"Typical of any turbocharger, as boost pressure is increased past the point where peak air flow [on the TD04] is produced (at around 19 psi of boost pressure), air flow, hence horsepower decreases."
Did the ADM WRXs get a different TD04 than our TD04L? If not, how do they figure that this turbo's maximum efficient boost if near 19 PSI when it is common belief on this board that one should not run more than 16 PSI on the stock turbo?
01-27-2003, 07:23 PM
#3
@Stoptech
Thread Starter
iTrader: (5)
Join Date: Nov 2002
Location: San Francisco, CA
Posts: 2,416
Car Info: 2002 WRX Wagon
In your opinion, what is the actual max efficient boost for the TD04L? I know that there are many variables to be considered such as altitude, temperature, humidity, etc. but in general, is 17PSI for example reasonably safe?
01-27-2003, 08:27 PM
#4
Registered User
iTrader: (4)
Join Date: Nov 2002
Location: plains of Eastern Montana
Posts: 270
Car Info: 04 GGA+
I know that some of the TD04's have been tuned at 17psi, this seems like the "max" they are tuning for. I'm guessing they are getting no additional power at higher levels (maybe decreasing power) or are running into safety issues. 17 psi would only be "safe" in my book w/ the proper engine mgt system in place and tuned by a respectable tuner.
Big Sky
Big Sky
01-27-2003, 08:36 PM
#5
@Stoptech
Thread Starter
iTrader: (5)
Join Date: Nov 2002
Location: San Francisco, CA
Posts: 2,416
Car Info: 2002 WRX Wagon
So this is a pretty vague question but how good is the stock ECU at realizing differences in boost pressures? By turning up the boost via MBC, would one be basically adding more air at any given RPM thus causing a lean condition? About how much higher than stock can you turn up the boost and still expect to have reasonable A/F ratios?
01-27-2003, 09:13 PM
#6
Guest
Posts: n/a
We do get the same TD04L turbo and to run them at 17 - 18psi(max) it most definitly requires a good ECU/Chip tune and exhaust and aim for a 12.** AFR, but at that boost level u can see on a dyno readout how the top end really flattens out quickly due to, 2 much heat as it has to spin so much faster with the small housings it has.Also the turbo APS is talking about sounds more like a TD05 from the earlier modles i think???
Last edited by andyas; 01-27-2003 at 09:20 PM.
01-27-2003, 09:56 PM
#7
@Stoptech
Thread Starter
iTrader: (5)
Join Date: Nov 2002
Location: San Francisco, CA
Posts: 2,416
Car Info: 2002 WRX Wagon
Originally posted by andyas
We do get the same TD04L turbo and to run them at 17 - 18psi(max) it most definitly requires a good ECU/Chip tune and exhaust and aim for a 12.** AFR, but at that boost level u can see on a dyno readout how the top end really flattens out quickly due to, 2 much heat as it has to spin so much faster with the small housings it has.Also the turbo APS is talking about sounds more like a TD05 from the earlier modles i think???
We do get the same TD04L turbo and to run them at 17 - 18psi(max) it most definitly requires a good ECU/Chip tune and exhaust and aim for a 12.** AFR, but at that boost level u can see on a dyno readout how the top end really flattens out quickly due to, 2 much heat as it has to spin so much faster with the small housings it has.Also the turbo APS is talking about sounds more like a TD05 from the earlier modles i think???
The Standard TD04 turbocharger installed on the WRX is well matched to the required power output of the stock WRX. At 220 hp - 230 hp and around 13 psi of boost pressure, the TD04 is within its limits and with the potential to supply enough air to produce 280 hp.
Typical of any turbocharger, as boost pressure is increased past the point where peak air flow is produced (at around 19 psi of boost pressure), air flow, hence horsepower decreases.
Typical of any turbocharger, as boost pressure is increased past the point where peak air flow is produced (at around 19 psi of boost pressure), air flow, hence horsepower decreases.
01-27-2003, 11:08 PM
#10
VIP Member
Join Date: Nov 2002
Location: colorado
Posts: 79
They are correct -- but
They are correct, the TD04L-13G can support 19 psi of boost, ( actually it can go to almost 25 psi), but only at flow rates that correspond to about 4500 rpm on a 2 liter engine (about 300 cfm).
At max volumetric flow ie about 360 CFM the turbo is hard pressed to support much more than 16-17 psi, and its effeciency is in the dumper (ie about 60%).
So technically they are correct. Most folks recommend the 16 psi range because they do not have the ability to map boost to rpm. If they did they could run higher boost at mid range rpms and taper near red line --- Hmmm that sounds familiar.
Larry
At max volumetric flow ie about 360 CFM the turbo is hard pressed to support much more than 16-17 psi, and its effeciency is in the dumper (ie about 60%).
So technically they are correct. Most folks recommend the 16 psi range because they do not have the ability to map boost to rpm. If they did they could run higher boost at mid range rpms and taper near red line --- Hmmm that sounds familiar.
Larry
01-28-2003, 09:00 AM
#11
Registered User
iTrader: (4)
Join Date: Nov 2002
Location: plains of Eastern Montana
Posts: 270
Car Info: 04 GGA+
Re: They are correct -- but
Originally posted by hotrod
They are correct, the TD04L-13G can support 19 psi of boost, ( actually it can go to almost 25 psi), but only at flow rates that correspond to about 4500 rpm on a 2 liter engine (about 300 cfm).
At max volumetric flow ie about 360 CFM the turbo is hard pressed to support much more than 16-17 psi, and its effeciency is in the dumper (ie about 60%).
So technically they are correct. Most folks recommend the 16 psi range because they do not have the ability to map boost to rpm. If they did they could run higher boost at mid range rpms and taper near red line --- Hmmm that sounds familiar.
Larry
They are correct, the TD04L-13G can support 19 psi of boost, ( actually it can go to almost 25 psi), but only at flow rates that correspond to about 4500 rpm on a 2 liter engine (about 300 cfm).
At max volumetric flow ie about 360 CFM the turbo is hard pressed to support much more than 16-17 psi, and its effeciency is in the dumper (ie about 60%).
So technically they are correct. Most folks recommend the 16 psi range because they do not have the ability to map boost to rpm. If they did they could run higher boost at mid range rpms and taper near red line --- Hmmm that sounds familiar.
Larry
Big Sky
Thread
Thread Starter
Forum
Replies
Last Post
John OBrien
Engine and Drivetrain
0
05-07-2009 10:03 AM
thissnsooosucks
Aftermarket Forced Induction - Turboed factory NA engines
1
02-05-2004 01:57 AM
