Help needed with wastegate maps

User topics relating to software that provides a tuning UI to alter ECU code and data

Moderator: Freon

Help needed with wastegate maps

Postby swifty » Wed Apr 26, 2006 7:15 am

Hi

I have a problem with my car that I believe can be sorted out with changes to the ecu. It is a boost control issue and causes the car to surge under moderate acceleration, with the boost fluctuating up and down as it accelerates. This is most pronounced between 3000 and 4000rpm in 5th and 6th gears. Car is a 2001 JDM STI with AF481-7546 ecu. Apparently it is a common problem when a fully decatted exhaust has been fitted, which mine has.

Before I start making any changes I have been trying to understand what's happening with the various maps and I have been looking at the rom from the car as well as other roms from other STIs from the JDM and EU markets. I have noticed that some roms have '#14 - Initial Wastegate Duty - A' and '#14 - Max. Wastegate Duty - A' maps but mine shows '#05 - Max.Wastegate Duty (A-Auto)' and '#05 - Max.Wastegate Duty (B-Manual)'.

I guess this is a map for an auto car and a map for a manual car, although the maps are identical, so I understand that. However, there is no initial wastegate duty map showing for my car either in Auto or Manual.

I used the latest version of xmlwrite integrated with ecuedit to produce the list of maps but I'm wondering if there is a way I can check everything has been identified correctly.

Going on from this, the Max Wastegate Duty map for my car is very different to those from other cars where there is an Initial Wastegate Duty map and a Max Wastegate Duty Map. The Initial and Max maps seem a lot flatter and smoother with the duty being a lot more constant through the rpm and load ranges. The throttle is shown as 16 bit on mine but 8 bit on the others.

I have compared the maps from my car with those from an EU STI. This is a very similar car, but produces less output in stock form than the JDM equivalent because it is tuned for EU emissions levels and fuel which is lower octane. I also compared it with the rom from the S202 and this also has Initial and Max maps which are quite flat.

So I have some questions,
firstly am I seeing all the maps correctly for my rom ?

second, if this is correct why is there only one wastegate duty map and why is it different to many other STI roms of similar spec / year ?

third, does it make any difference if the throttle is shown as 16 bit on mine but 8 bit on others ?

and finally, can anyone give me any guidance on making changes to the wastegate duty maps ?

I have attached a word document showing the lists of maps from the 3 cars and their wastegate duty maps so you can see what I mean. My rom is in the JDM STI 2001-2003 section. There is another rom from a 2003 car and this has identical maps and also displays the same, ie only one wastegate duty map.

If anyone can answer my queries and help me resolve the boost issue I'd be most grateful.

Many thanks
Attachments
Wastegate.doc
(224 KiB) Downloaded 437 times
swifty
 
Posts: 109
Joined: Wed Mar 22, 2006 3:01 am
Location: Behind a keyboard

Re: Help needed with wastegate maps

Postby moxie » Wed Apr 26, 2006 8:08 am

swifty wrote:and finally, can anyone give me any guidance on making changes to the wastegate duty maps ?



I am going to defer to some of the others on the more software specific questions. I dont feel right commenting as I haven't looked at many other roms other than mine, which i just use the Wastegate Max Duty Map for.


In terms of tuning out the problem, what would be useful is a datalog of:
TPS, RPM, Boost, WG Duty, MPH

Make a few runs in 3rd or 4th gear if possible, so the problem is evident.
That should give enough data to figure out what is causing the problem.

The map does look a little funky, what turbo setup is used on your STi?
moxie
 
Posts: 18
Joined: Mon Aug 15, 2005 7:02 am

Postby swifty » Wed Apr 26, 2006 9:20 am

I will try to get a log of all that tonight and post it up, thanks.

Turbo is an IHI VF?? (will check) not a twin scroll though.
swifty
 
Posts: 109
Joined: Wed Mar 22, 2006 3:01 am
Location: Behind a keyboard

Postby swifty » Thu Apr 27, 2006 2:42 am

Here is a log from a run I did last night. As usual when you have a problem it never seems to show up when you want it to. I don't know if it is because the weather has warmed up over the last week or so but the surging seems only very slight now. Here's the log anyway, perhaps it will show something else up, I'm interested in getting the best from the car so would be happy for any feedback that would help me achieve this.

I started off with a run up to an indicated 90mph (4000rpm) in 6th then cruised a bit, reduced speed a number of times to around 60/70 (3000rpm) and applied throttle to attempt to make it surge. Then there was a slow down to around 20mph to double back. The MPH figures are wrong cos I selected the 'convert kph to mph' option but the car is fitted with some device that does this already so I think multiplying the speed by 1.609 makes it a bit more realistic. I don't know how to put these figures into a graph.

The file is in csv format.

Thanks
Attachments
ecuExplorer [AF481] 26-04-2006 21h07m43s.txt
(79.1 KiB) Downloaded 742 times
swifty
 
Posts: 109
Joined: Wed Mar 22, 2006 3:01 am
Location: Behind a keyboard


Return to Tuning Software

Who is online

Users browsing this forum: No registered users and 10 guests

cron