Boost Limits?

ZuMBLe · 07-17-2006, 04:28 AM

Where does everyone have their boost limits set at? What's your elevation and turbo?

Does anyone know that parameters have to be met before the ecu throws the overboost code? My ECU threw a code after I stabbed the throttle and let off a few times repeatedly. I guess I spiked a few times within a given amount of time so the ECU cut fuel and turned on some dash lights..

Should I just raise the boost limit? What's the correct way to start tuning out spiking?

WolfPlayer · 07-17-2006, 07:07 AM

To tune out spiking I like to use the turbo dynamics course gain (positive value table). Also take a look at your boost tables and make sure that you aren't specifying too much boost down low (like 19psi at 1000rpms or something). Numbers like that will bump up the turbo dynamics really high for no reason at all (because you can't achieve 19psi @ 1000rpms and yet you are telling the computer to try to do it).

As far as the overboost table, it really does depend on that whole table. I run around 21.3 psi in the last cell (and run a 19psi midrange tune).

t

ZuMBLe · 07-17-2006, 07:11 AM

Thanks for the info. I just wanted to make sure it was safe to play with the table. It would seem this table would have to be modded at one point or another since many people run over 20psi. Good tip about the boost tables!

Quote:

Originally Posted by WolfPlayer

To tune out spiking I like to use the turbo dynamics course gain (positive value table). Also take a look at your boost tables and make sure that you aren't specifying too much boost down low (like 19psi at 1000rpms or something). Numbers like that will bump up the turbo dynamics really high for no reason at all (because you can't achieve 19psi @ 1000rpms and yet you are telling the computer to try to do it).

As far as the overboost table, it really does depend on that whole table. I run around 21.3 psi in the last cell (and run a 19psi midrange tune).

t

TraSTi · 07-17-2006, 07:31 AM

What would be a safe boost on stock cars with dp? I would like safe but fast because i know 15psi is safe but still i want more POWER!! Does 20psi seems safe, with stock fuel pump stock injectors? Also what is the lowest rpm i can go full boost at (i know it depends alot in the hardware but usually in our cars)?

WolfPlayer · 07-17-2006, 10:27 AM

I like 19 psi midrange to 15.5 psi at redline. Lots of people run 20 psi midrange (on spoolup). But, I like to run 19 psi.

t

ablair544 · 07-18-2006, 08:27 AM

I am stock and my fuel cut only hits in fourth....i only run 15 lbs at redline and it hits. Spike wise ive been running 17 or so. Boost is fine in any other gear at redline...but it only hits fuel cut in fourth, even though the boost is the same as it is in every gear.

WolfPlayer · 07-18-2006, 09:13 AM

Quote:

Originally Posted by ablair544

I am stock and my fuel cut only hits in fourth....i only run 15 lbs at redline and it hits. Spike wise ive been running 17 or so. Boost is fine in any other gear at redline...but it only hits fuel cut in fourth, even though the boost is the same as it is in every gear.

Do you have any engine management at all?

t

overdose · 07-24-2006, 02:57 AM

I'm running 20.5 soon as I can get it (~3000rpm) and that holds until about 5000-5200rpm then falls to 15.0-15.5 by redline, this seems to be the "limit" with the factory solenoid (WGDC's are at 90.2%)... seems fine to me, car never loses DA and runs pretty good, since I have ported manifolds/crosspipe/tmic i'm going to install a prodrive solenoid and see what else can be had

but, since i'm already flowing 290g/s of air, chances are i'll just pick up some torque and end up getting a 20g anyway :P

ZuMBLe · 07-24-2006, 04:40 AM

Intersting. The best I get is about 256g/s of air. This is on a 16G. Your car seems more efficient. I'm running a stock airbox with prova filter, txs stealthback with hiflow cat to a STi axleback.

Quote:

Originally Posted by overdose

I'm running 20.5 soon as I can get it (~3000rpm) and that holds until about 5000-5200rpm then falls to 15.0-15.5 by redline, this seems to be the "limit" with the factory solenoid (WGDC's are at 90.2%)... seems fine to me, car never loses DA and runs pretty good, since I have ported manifolds/crosspipe/tmic i'm going to install a prodrive solenoid and see what else can be had

but, since i'm already flowing 290g/s of air, chances are i'll just pick up some torque and end up getting a 20g anyway :P

2fas4u · 07-24-2006, 04:45 AM

GT-30R - 22 psi currently
GT-30R - 24 psi (after tuesday this week)

300 feet Agl.....

crystal_Imprezav · 07-24-2006, 04:47 AM

Odd I see 290+ a bit easily on hot days around here. I also can see slightly over 300 on colder days. I am running 19psi with a custom typhoon and txs TBE catless. My LTFT are on the money with slight increases in the mid voltage areas put up top is the same. I can hit about 3.1 load with no problem but when I had too much increases in my intake calibration I was hitting close to 3.4 load. Try tuning your intake calibrations a bit, it should help.

WolfPlayer · 07-24-2006, 06:33 AM

All depends on how closely your intake calibration meets the truth. For example, if your AFRs are specified in your Fuel map are different then reality then the g/s won't be true. I was pulling 300g/s fairly easily before I tuned my intake calibration. I tuned the intake calibration to match the actual AFR curve specified in the fuel map and now I don't pull 300g/s anymore. Simple as that. If your actual AFR is richer than what is specified in the fuel map then your g/s isn't true; rather, the g/s will be too high and make you think you are making more power then you really are.

t

ZuMBLe · 07-24-2006, 10:14 AM

Interesting. I'm going to have to read up on your guide on how to retune the intake. Even though I'm running a stock airbox.

Quote:

Originally Posted by WolfPlayer

All depends on how closely your intake calibration meets the truth. For example, if your AFRs are specified in your Fuel map are different then reality then the g/s won't be true. I was pulling 300g/s fairly easily before I tuned my intake calibration. I tuned the intake calibration to match the actual AFR curve specified in the fuel map and now I don't pull 300g/s anymore. Simple as that. If your actual AFR is richer than what is specified in the fuel map then your g/s isn't true; rather, the g/s will be too high and make you think you are making more power then you really are.

t

crystal_Imprezav · 07-24-2006, 04:20 PM

Yea its almost impossible to get them spot on. I am using almost stock intake calibration values and tweaking the injector scale a tiny bit to get mine closer. My thinking is either the stock intake calibration is too high as is which results in why it the stock AFR's read richer than true or the injector scale is set too high not giving enough credit to the injectors flowing a bit higher than they truely are. This is why when adding an aftermarket intake that flows a bit better the AFR's are leaner but closer to what is set in the stage2 map.

ZuMBLe · 07-24-2006, 06:15 PM

My wideband shows I'm in the 10s at WOT but the map is mapped for 11s. This thread has gone off topic but still good info. I guess maybe the intake calibration will help the car get back in to the 11s?

Quote:

Originally Posted by crystal_Imprezav

Yea its almost impossible to get them spot on. I am using almost stock intake calibration values and tweaking the injector scale a tiny bit to get mine closer. My thinking is either the stock intake calibration is too high as is which results in why it the stock AFR's read richer than true or the injector scale is set too high not giving enough credit to the injectors flowing a bit higher than they truely are. This is why when adding an aftermarket intake that flows a bit better the AFR's are leaner but closer to what is set in the stage2 map.

07-17-2006, 04:28 AM	#1
ZuMBLe Senior STI Driver Car: 05 CGM FXT Location: NY Posts: 323 Join Date: Feb 2006 Trader Rating: (2)	Boost Limits? Where does everyone have their boost limits set at? What's your elevation and turbo? Does anyone know that parameters have to be met before the ecu throws the overboost code? My ECU threw a code after I stabbed the throttle and let off a few times repeatedly. I guess I spiked a few times within a given amount of time so the ECU cut fuel and turned on some dash lights.. Should I just raise the boost limit? What's the correct way to start tuning out spiking? This ad is not endorsed by this member. Please register or login to hide this ad.

07-17-2006, 07:07 AM	#2
WolfPlayer Moderator & ECU Tech Car: 05 CGM STI Fav Mod: mo boostaz Location: Fredneck, MD Posts: 3,622 Join Date: Jun 2004 Trader Rating: (6)	To tune out spiking I like to use the turbo dynamics course gain (positive value table). Also take a look at your boost tables and make sure that you aren't specifying too much boost down low (like 19psi at 1000rpms or something). Numbers like that will bump up the turbo dynamics really high for no reason at all (because you can't achieve 19psi @ 1000rpms and yet you are telling the computer to try to do it). As far as the overboost table, it really does depend on that whole table. I run around 21.3 psi in the last cell (and run a 19psi midrange tune). t

07-17-2006, 07:31 AM	#4
TraSTi Professional STI Racer Posts: 830 Join Date: Apr 2006 Trader Rating: (2)	What would be a safe boost on stock cars with dp? I would like safe but fast because i know 15psi is safe but still i want more POWER!! Does 20psi seems safe, with stock fuel pump stock injectors? Also what is the lowest rpm i can go full boost at (i know it depends alot in the hardware but usually in our cars)?

07-17-2006, 10:27 AM	#5
WolfPlayer Moderator & ECU Tech Car: 05 CGM STI Fav Mod: mo boostaz Location: Fredneck, MD Posts: 3,622 Join Date: Jun 2004 Trader Rating: (6)	I like 19 psi midrange to 15.5 psi at redline. Lots of people run 20 psi midrange (on spoolup). But, I like to run 19 psi. t

07-18-2006, 08:27 AM	#6
ablair544 Senior STI Driver Car: 04 silver STI Fav Mod: turboback exhaust Location: laurel, md Posts: 348 Join Date: Jul 2006 Trader Rating: (1)	I am stock and my fuel cut only hits in fourth....i only run 15 lbs at redline and it hits. Spike wise ive been running 17 or so. Boost is fine in any other gear at redline...but it only hits fuel cut in fourth, even though the boost is the same as it is in every gear.

07-24-2006, 02:57 AM	#8
overdose Senior STI Driver Car: 2005 WRB STi Fav Mod: roadhead Location: Grand Rapids, MI Posts: 314 Join Date: Dec 2005 Trader Rating: (0)	I'm running 20.5 soon as I can get it (~3000rpm) and that holds until about 5000-5200rpm then falls to 15.0-15.5 by redline, this seems to be the "limit" with the factory solenoid (WGDC's are at 90.2%)... seems fine to me, car never loses DA and runs pretty good, since I have ported manifolds/crosspipe/tmic i'm going to install a prodrive solenoid and see what else can be had but, since i'm already flowing 290g/s of air, chances are i'll just pick up some torque and end up getting a 20g anyway :P

07-24-2006, 04:45 AM	#10
2fas4u Silver Member Car: 05 STI Location: Manchester, Maryland Posts: 1,864 Join Date: Aug 2005 Trader Rating: (3)	GT-30R - 22 psi currently GT-30R - 24 psi (after tuesday this week) 300 feet Agl.....

07-24-2006, 04:47 AM	#11
crystal_Imprezav Spec C Club Car: Slow 05 STi Fav Mod: Loping Idle Location: Chewy's Garage Posts: 1,862 Join Date: Mar 2005 Trader Rating: (11)	Odd I see 290+ a bit easily on hot days around here. I also can see slightly over 300 on colder days. I am running 19psi with a custom typhoon and txs TBE catless. My LTFT are on the money with slight increases in the mid voltage areas put up top is the same. I can hit about 3.1 load with no problem but when I had too much increases in my intake calibration I was hitting close to 3.4 load. Try tuning your intake calibrations a bit, it should help.

07-24-2006, 06:33 AM	#12
WolfPlayer Moderator & ECU Tech Car: 05 CGM STI Fav Mod: mo boostaz Location: Fredneck, MD Posts: 3,622 Join Date: Jun 2004 Trader Rating: (6)	All depends on how closely your intake calibration meets the truth. For example, if your AFRs are specified in your Fuel map are different then reality then the g/s won't be true. I was pulling 300g/s fairly easily before I tuned my intake calibration. I tuned the intake calibration to match the actual AFR curve specified in the fuel map and now I don't pull 300g/s anymore. Simple as that. If your actual AFR is richer than what is specified in the fuel map then your g/s isn't true; rather, the g/s will be too high and make you think you are making more power then you really are. t

07-24-2006, 04:20 PM	#14
crystal_Imprezav Spec C Club Car: Slow 05 STi Fav Mod: Loping Idle Location: Chewy's Garage Posts: 1,862 Join Date: Mar 2005 Trader Rating: (11)	Yea its almost impossible to get them spot on. I am using almost stock intake calibration values and tweaking the injector scale a tiny bit to get mine closer. My thinking is either the stock intake calibration is too high as is which results in why it the stock AFR's read richer than true or the injector scale is set too high not giving enough credit to the injectors flowing a bit higher than they truely are. This is why when adding an aftermarket intake that flows a bit better the AFR's are leaner but closer to what is set in the stage2 map.