How to Tune 5EAT Line Pressure

If you have SI-Drive, read the whole thread before proceeding! Requested Torque also tunes Target Boost!!!

For those who don't quite get the written directions in the other 5eat threads, here is the picture book:

If you want to post your own revised DBW tables, please also note your kind of transmission, turbo, and any other related power and spool mods, such as IPT or TransGo mods, header, DP, Exhaust, FMIC, etc. All these things will change what Requested Torque values are going to work best for you.

First: What is line pressure?

Line pressure is the ATF pressure applied to various components of your transmission to move them into a certain position. Very simply put, more line pressure means your 5eat will shift harder and firmer. Less line pressure means your 5eat will shift slower and softer (more luxurious, for your wives).

Line pressure is controlled by the line pressure solenoid. A pump pumps the fluid, and the line pressure solenoid controls the pressure seen by the transmission. Other solenoids (all on the valve body) control where the pressurized ATF is sent, which in turn can do such things as change gears, lock up the Torque Converter or Center Diff, etc.

Line pressure is dependent on 4 things:

Your current RPM.

Your current MPH (speed).

Your current corresponding Requested Torque map value, which itself is a product of accelerator pedal position and rpm (more to come on this).

Your ATF temperature (if your ATF gets too hot, the line pressure gets increased by the TCU, since excessive trans slipping (a product of too little line pressure) will produce a lot of heat via friction. This friction also wears out your clutches (automatics have a LOT of clutches, which work together in groups called clutch packs). When these burn up, you get a lot less friction. Ask me how I know.

Disclaimer: I am not responsible if you brick your ECU, ruin your transmission, or you crash your car and die in a slow and painful fire. Proceed with caution.

If you don't know how to use RomRaider, then don't do this, and go learn how to use RomRaider.

Steps:

Open Romraider.

Open your car's ROM.

Expand the Folder named "Drive-by-Wire Throttle (DBW)"

Open the 'Requested Torque (accelerator pedal)' table.

Open the 'Target Throttle Plate Position (Requested Torque) table.

You will be changing the table values that are surrounded by RED.

http://lh4.ggpht.com/_u9ivxKMxaQw/TNdXvvBiecI/AAAAAAAADbg/Pd4_tag1SaA/s640/How%20to%20Tune%20Requested%20Torque%20Before.jpg

Decide by what percent you want to increase you line pressure. This is up to you. I increased mine by 30% in this example. So decide on a %, and remember it. Convert that percentage to a multiple. So 30% will be "1.3"

Multiply every value circled in RED by your multiple (1.3 in this example).

It should look like this now:

http://lh5.ggpht.com/_u9ivxKMxaQw/TNdYw0AWTQI/AAAAAAAADbs/XrPWEN6UzsE/s640/How%20to%20Tune%20Requested%20Torque%20After1.jpg

Notice all the values previously circled in Red are now increased by 30%.

Check your work to make sure everything looks right.

Now save the ROM and go test drive. Give the car an opportunity to warm up to operating temperature first.

Fine Tuning with Logging

Warning: I have not tested any fine tuning yet. This is theory, and you should have a at least some working knowledge of tuning and logging.

Disclaimer: Not my fault if anything in your life goes wrong EVER, including but not limited to you crashing your car, your dying, your wife leaving you, or anything else that may or may not be limited to this post.

Please NOTE: The two DBW Tables, Requested Torque (RT) and Target Throttle Plate Position (TP) are symbiotic (for lack of a better word). Changing one changes the other. The two tables form the relationship between the accelerator pedal and the throttle body butterfly.

Furthermore, SI-Drive models throw Target Boost into this mix, so if you are not careful, you can VERY EASILY BLOW YOUR ENGINE BY OVERBOOSTING.

Be cognizant that changing one will mess with the other. If you say alter an entire column set of RT values, then you might want to compensate with the TP top row, see first post). Since the two tables work together, there is an infinite number of ways you can actually tune for line pressure than just the simple primer in Post #1.

If you have SI-Drive you also need to compensate with target boost tweaks, and perhaps other variables as well.

Another fun note: Generally speaking, you can almost consider "Requested Torque" to be a synonym for LINE PRESSURE for this exercise. It's not entirely accurate because actual line pressure is dependent on many factors, including those listed in Post 1. But hopefully it helps you better comprehend what you are tuning.

Steps:

With car completely warmed up and after driving around normally for a little while: Log whatever associated values you can that relate to Requested Torque and shifting

The main ones that come to mind are Accelerator Pedal Position, and RPM, and Gear Position (1,2,3,4,5).

Consider using the defrost button to start and stop logs, then keep track of what log number incurred what amount of shift firmness. You will need to do a lot of logging to really fine tune the Requested Torque table. Perhaps have a buddy present.

Do a pull of some predetermined accelerator position %. Log the period immediately before, during, and after a gear shift. Note whether you want more or less or the same line pressure amount at that shift.

Rinse and repeat. Try to get a range of logs at different accelerator pedal positions and RPMs.

Reference your notes against the logs you took, and the increase the areas of the Requested Torque map that correspond to your logged parameters.

There is perhaps a better way to do this. I don't know. No one has written about doing any of this. Hopefully the community members will test out different setting and share on these boards.

-ClimberD

saved for what I have done that works. don't hold your breath.

So far I have been running around on a +30% Requested Torque tune. I need less Requested Torque (RT) below 3000rpms because I get no power there anyways. I get some shift shock on my 1-2 shift. Hopefully I can cure that without sacrificing the safety of other shifts. I get a positive shift above 3000 RPMs, and don't see a need to mess with that just yet. More to come.

IPT VB mod

7cm TD06-20G (I know, not the best 20G setup, it's temporary).

eBay custom TMIC

APS EL Header, UP

Tial 38mm EWG, to air

Cobb HFC DP

straight through exhaust

AEM CAI (but not for long)

way to go, CD -- how do you like the alterations you've made so far?

edit: nm, just saw your initial take in the other thread -- watching to see how this develops for you gents though.

I don't have a 5EAT so this doesn't affect me, but i'm glad someone is putting this together.

This was one of the huge pros for getting an aftermarket tune on my Grand Am GT back in the day. The increased transmission line pressure did help with firmer shifts...but it wasn't like a "slam" into gear. Also helped prevent slippage with the higher torque levels.

Hope you know what Si Dive basically does...different throttle opening, boost...and theres more then what they tell us:spin:

Yes. I don't know about your ECU logic, but on my WRX, plus the FXTs I've tuned, altering requested torque changes final boost target also. Perhaps one of you could log manifold relative pressure and boost error both before and after making these changes to the tables to be sure? I would hate to see anyone overboosting, running into det, over simply plastering their hair on the windshield when they run into fuel cut.

so what were the outcomes from your requested torque changes in the past?

From Cobb

"...The shape of this table determines the responsiveness of the throttle as it determines BOTH

throttle duty cycle AND desired boost (in those vehicles where boost is a function of desired torque and

engine speed). To increase responsiveness increase the slope of this plane from zero throttle position

toward full throttle. To decrease sensitivity decrease the desired torque in the appropriate throttle/engine

speed areas."

so what were the outcomes from your requested torque changes in the past?

What I found was that when requested torque in the throttle table is higher than the header in the last row of the boost table, the boost target is extrapolated beyond the value in that cell. You will get higher boost than called for in table and yet no error. If you only set the same requested value in throttle map as in the boost map's last row, it seems you may not get 100% throttle plate angle.

I dealt with this by setting the value just slightly higher and reducing the boost target until I got the value I wanted in my logs and error zeroes out. I don't know if this is the right way to deal with it but it worked for me.

I'm just suggesting that when changing the requested torque values it would be a good idea to log boost to be sure nothing changed unexpectedly.

I think we need some tuner folks input on this one as I am not sure what we are getting into as far as that requested torque table. I'll solicit some feedback myself outside these channels.

Thanks. I would really hate to see someone take out an engine trying to save a transmission. I'd like even more to be wrong about the whole thing and scaring you all for nothing.

Really important warning there!

There is a Throttle Tuning thread on RomRaider, and those guys know their stuff.

Man I wish I had SI drive... Would love to have access to something other than WG on or off.

Potentially a dumb question, so flame or educate as you see fit.

Is this bascially a way to ask an otherwise stock trans to perform similar to having the IVT VB mod done? It sounds like you are going after the same benefits. I don't know the particulars of the VB mod (if solenoids are replaced with ones that scale differently given the stock input voltages or something).

Obviously the VB rebuild would have several benefits outside more positive engagement (not the least of which being a visual inspection of the state of things).

Sorry for veering onto the "topic shoulder".

IPT supposedly makes changes to every solenoid. Frankster believes that the trans will work fine without a VB mod so long as line pressure is high enough. In short, the answer is Yes, this is a free way of getting similar results. But this can potentially be even better. The highest possible line pressure is achieved with both a ported valve body, and tuning for higher line pressure. The VB mod should increase the ceiling.

Perhaps I should have waited until I sold my IPT VB to say that.

I keep reading that the requested torque #s are just arbitrary and used for scaling purposes. I realize that by just scaling it up to 420 on the high end doesn't mean you will magically crank that much torque, I just wonder if the 5EAT ECU logic does make a difference in this regard or we're on a wild goose hunt here.

My concern so far is how these table play with the rest of them, namely boost tables, which affect WGDC, etc.

ClimberD, regarding your comment that my table cuts off at 84% throttle angle, here:

http://www.cobbforums.com/forums/showthread.php?66426-Possible-bug-Throttle-Angles-A-C-values-seem-off&p=628948

84% = WOT in ATR

Oh, and then I got headaches reading these threads:

http://www.dirtyimpreza.com/forums/showthread.php?t=5208

http://www.wrx.com.au/forum/viewtopic.php?f=31&t=50862&view=next

Same exact thing. There was another discussion on many pages on NASIOC, I can't find it at the moment.

I keep reading that the requested torque #s are just arbitrary and used for scaling purposes. I realize that by just scaling it up to 420 on the high end doesn't mean you will magically crank that much torque, I just wonder if the 5EAT ECU logic does make a difference in this regard or we're on a wild goose chase here.

ClimberD, regarding your comment that my table cuts off at 84% throttle angle, here:

http://www.cobbforums.com/forums/showthread.php?66426-Possible-bug-Throttle-Angles-A-C-values-seem-off&p=628948

As far as anyone knows, that is correct for MT ECUs.

As far as my reading the Vacation Pix goes, that is Also correct for 05-06 AT ECUs, but INCORRECT FOR THE TCU READING THE ECU. RT very clearly is a value referenced to determine line pressure. I have said it many times now. Where is the confusion.

Perhaps it is that 5eat guys just go by whatever the MT guys do and think. Very similar ECUs, but they don't have an AT TCU, so it does not matter.

The confusion is that my throttle position table is actually the throttle opening angle. 84% is the max in Access Tuner Race. I have not checked in RomRaider yet. The scale is the same as it was on the stock tune, Stage 1 and Stage 2. On the 5EAT tunes. I don't see how it could be off.

ATR displays the raw value as used by the ECU, which is the throttle angle in degrees. 84 deg. is WOT. RomRaider applies a conversion to this value to display as throttle opening angle (%) with the assumption that 84 deg = 100% throttle opening. There is no difference between the two as long as you understand that they are two different units and tune accordingly (i.e. 84 deg. in ATR if opened in RR would appear as 100% and vice versa).

As far as anyone knows, that is correct for MT ECUs.

As far as my reading the Vacation Pix goes, that is Also correct for 05-06 AT ECUs, but INCORRECT FOR THE TCU READING THE ECU. RT very clearly is a value referenced to determine line pressure. I have said it many times now. Where is the confusion.

 

Perhaps it is that 5eat guys just go by whatever the MT guys do and think. Very similar ECUs, but they don't have an AT TCU, so it does not matter.

Yes, it's one of those hidden relationships. On the one hand high requested torque may call for increased line pressure in the 5EAT trans. OTOH it can restrict throttle angle to less than 100% in 1st and 2nd gear in a manual. There are still a lot of undefined tables in the ECU logic... what may have no side-effects for the MT guys may be horrible for the 5EAT, and vice-versa.