Custom tunes safe for track usage?

[Sleepless]

Given how sensitive the engines seem to be regarding injector seals and lots of track driving, I'm a bit hesitant to add N/A performance parts like a de-cat header, and being confident that the custom tune is safe for lots of track use.

I haven't heard of anyone having an issue with just a header and tune, but I still worry. Should I worry? Or, is it dirt simple to get a safe tune?

Anyone out there with NA mods and a custom tune tracking the car a lot?

[CSG Mike]

It is if your tuner regularly tunes track/race cars. There are a lot of tuners who can do perfectly safe street tunes, that aren't sustainable on track.

Ask your tuner to come to the track with you to do some live logging from the passenger seat. He can make small changes to your tune immediately, or inform you to pull off if anything is funky. This also serves to get him a real datalog from hard driving, which will further improve his tunes in the future.

[JB86'd]

@CSG Mike would the safety of that tune primarily have to do with knock that wouldn't do harm under street driving temps and load, but under heavy engine load and high temp could kill the engine?

[CSG Mike]

Originally Posted by JB86'd

@CSG Mike would the safety of that tune primarily have to do with knock that wouldn't do harm under street driving temps and load, but under heavy engine load and high temp could kill the engine?

Temps, sustained load, heat soak, how aggressive the tune is, etc. I can literally list hundreds of variables that are different.

Here's a simple example. Lets say you have a fairly typical tune that doesn't knock on the dyno or street. After one pull on the dyno, you see a small blip, if even that, in the temps that quickly go away. Now, at the track, you're doing back to back pulls. That blip is now a constant heat gain. All the sudden, your tune that makes nice numbers on the street when you do one pull at a time is too aggressive for the conditions presented. Now you're making no power, because the ECU sees knock, and is retarding timing. Now, because the ECU is retarding timing, your EGT skyrockets. Because the EGT skyrockets, you're now getting more heat in your engine by from the exhaust manifold, and are simultaneously destroying your catalytic converters. Once the cats are destroyed, you have more flow, causing more air to be seen by the MAF, which in turn causes the engine to get more fuel, which is more combustion, which is more heat.

You can see how it spirals out of control.

Most tuners will just flat out retard timing a few degrees across the board for track use. That's not a real solution.


How many tuners on this board do 10 back to back WOT pulls on their dyno with the hood closed, and just air movers blowing in the front opening, to simulate hard use? How many tuners here give you a dyno of individual pulls, instead of doing a lot of back to back pulls, until both temperatures and output readings hit equilibrium, giving you a *real world number* of how your car performs?

[JB86'd]

@CSG Mike thanks so much for that writeup, reminds me how little I know about tuning and how many factors there are to be considered. Definitely something for everyone to consider.

[ATL BRZ]

Originally Posted by Sleepless

Given how sensitive the engines seem to be regarding injector seals and lots of track driving, I'm a bit hesitant to add N/A performance parts like a de-cat header, and being confident that the custom tune is safe for lots of track use.

I haven't heard of anyone having an issue with just a header and tune, but I still worry. Should I worry? Or, is it dirt simple to get a safe tune?

Anyone out there with NA mods and a custom tune tracking the car a lot?

@moto-mike at Moto-East tuning made me two separate tunes taking my mods into account. I have a JDL UEL header and full 2.5" exhaust, 3" intake, and a flex fuel kit. One is a custom track tune since I track my car frequently and use E85 most of the time. The track tune is dialed back a little to ensure safety against knock and bad AFRs. He also made me a separate street tune (with more aggressive timing and top end HP).

I'm very happy with the tunes and have no issues flashing back and forth between the two knowing that Mike's top tuning priorities are safety and reliability.

[glamcem]

I would do everything to get rid of that stupid torque dip and cats from the header ceramic coated, good quality EL header and some custom tune would be my choice to each his own..
maybe you should discuss your end goals ( track reliability in this case) with an experienced tuner (Mike or Bob) and hear from them.. both tuners regularly track their cars as far as I can tell

[steve99]

Originally Posted by Sleepless

Given how sensitive the engines seem to be regarding injector seals and lots of track driving, I'm a bit hesitant to add N/A performance parts like a de-cat header, and being confident that the custom tune is safe for lots of track use.

I haven't heard of anyone having an issue with just a header and tune, but I still worry. Should I worry? Or, is it dirt simple to get a safe tune?

Anyone out there with NA mods and a custom tune tracking the car a lot?

Assuming your tune is already pretty good for street. AFR knock fuel trims ect.

Log your tune on street check its pretty well knock free during street driving and normal temps. Sort out any knock during street driving or single dyno pulls at normal temps first.

best simplest "insurance" for track day is a tank of really good fuel


Their are tables in the ECU to reduce timing when Intake Air temps climb and when ECT Engine coolant temps increase.

Timing compensation (IAT)
Timing compensation (IAT) Compensation

These two tables work in conjunction with each other

eg at IAT -122F retard is -2.11 degrees but it will be applied differently depending on engine load/RPM eg at engine load =1 rpm = 6000 the scaling factor is -70% do actual retard = -0.663 degrees

0% = full retard applied
-100% = no retard applied

This is for romraider, ecutek labels and scales these tables differently but they work the same.

What you can do is alter the scaling or the retard values where you see knock start when temps increase at the rpm/load points.

Suggested starting point would be altering the -70% values in the 5000-7000 rpm ranges to -50% to increase the retard at higher IAT temps higher load/rpm

I also insert -1.4 degrees at 104F just to get the compensation to cut in a bit earlier. in Timing compensation (IAT) table.

Then have a look at the
Timing Compensation A (ECT) Engine Coolant temp
Timing compensation B (ECT)

You will notice on some tunes (including stock tune) these are all zero ie no retard applied regardless on engine coolant temp

For a bit of safety add maybe -2 degrees retard at 212F and -3 degrees at 239F coolant temps ie change the last two cells. (this is what most WRX ecu run.)

[brn12345]

To OP. I run my car on track days and usually the sessions are 30 minutes each. I have headers and no cats on my car. I run OFT Stage 2 EL tune on my car. When at the track I run VP MS103 and usually fill up a day before and drive around for the ecu to compensate. I have logged many track days and I can tell you that with pump gas running stock tune or tuned the car will knock. So to reemphasize, run a high enough octane fuel at track.

Another thing I noticed is that my oil temps were at around 290F during the 30 min run. This is way to high. I have ordered an oil cooler and will log temps and impact during coming track days.

I would also recommend getting your tuner to add safety measures related to temperature rises as added insurance.

To sum up, I have run the car at the track at full throttle for at least ten 30min sessions with oil temps at 290F using VP MS103 fuel and have not had knock or injector seal issues.

[troek]

im gona data log a few laps at my next session. although ive never had the IAM drop, it will be interesting to see if theres any knock at all. ive done 4-5 pulls on the highway with no knock, but oil only got up to 230ish.

[CSG Mike]

Originally Posted by steve99

Assuming your tune is already pretty good for street. AFR knock fuel trims ect.

Log your tune on street check its pretty well knock free during street driving and normal temps. Sort out any knock during street driving or single dyno pulls at normal temps first.

best simplest "insurance" for track day is a tank of really good fuel


Their are tables in the ECU to reduce timing when Intake Air temps climb and when ECT Engine coolant temps increase.

Timing compensation (IAT)
Timing compensation (IAT) Compensation

These two tables work in conjunction with each other

eg at IAT -122F retard is -2.11 degrees but it will be applied differently depending on engine load/RPM eg at engine load =1 rpm = 6000 the scaling factor is -70% do actual retard = -0.663 degrees

0% = full retard applied
-100% = no retard applied

This is for romraider, ecutek labels and scales these tables differently but they work the same.

What you can do is alter the scaling or the retard values where you see knock start when temps increase at the rpm/load points.

Suggested starting point would be altering the -70% values in the 5000-7000 rpm ranges to -50% to increase the retard at higher IAT temps higher load/rpm

I also insert -1.4 degrees at 104F just to get the compensation to cut in a bit earlier. in Timing compensation (IAT) table.

Then have a look at the
Timing Compensation A (ECT) Engine Coolant temp
Timing compensation B (ECT)

You will notice on some tunes (including stock tune) these are all zero ie no retard applied regardless on engine coolant temp

For a bit of safety add maybe -2 degrees retard at 212F and -3 degrees at 239F coolant temps ie change the last two cells. (this is what most WRX ecu run.)

Totally valid, but generally using the IAT correction is reserved for FI

I absolutely agree, race gas is cheap insurance, even on a completely stock NA car.

[coyote]

I run egt sensors on the dyno and capture knock by individual cylinders. That, in conjunction with data collection at the track, is the only way to build a rock solid tune. Pulling timing to address heat is like adding more lock to tame understeer. There are unused tables in these ROMs that can be used to cater for the needs of just about any track car but most of the tunes I've seen are very basic and not even safe for the street.

Sent from my Nexus 4 using Tapatalk

[glamcem]

anyone have a data supporting the race gas effectiveness?

[steve99]

Originally Posted by coyote

I run egt sensors on the dyno and capture knock by individual cylinders. That, in conjunction with data collection at the track, is the only way to build a rock solid tune. Pulling timing to address heat is like adding more lock to tame understeer. There are unused tables in these ROMs that can be used to cater for the needs of just about any track car but most of the tunes I've seen are very basic and not even safe for the street.

Sent from my Nexus 4 using Tapatalk

+1

Just trying to come up with something for NA guys going to track occasionally.

Yep the serious track warriors will need oil coolers , specific track tunes possibly bigger radiators venting ect.

got any definition data for the "unused tables" ?? :-) or are you talking about defined tables that just are not used by most tuners.