EGT on FA20 BRZ Turbo

Good day,

I'm running in to a problem with an FA20 Turbo BRZ. The EGT on a Dynorun going really high up to 1100°C.

Some infos first about the car:

Fullybuilt engine with a CR of 10.5:1

4 in to 1 header with a BorgWarner EFR-6758 0.85A/R V-Band

3" Exhaustsystem with a 100cell race kat on the back.

We use 98Octane fuel with RaceGas OctaneBooster so we should be now above 108Octane.

We fitted a Radium fuelsystem with Deatschwerks 700cc Injectors. Also new OEM DI Injectors.

Ah and of course the car is tuned right now with ECUTEK.

The car making right now on the Dynapack 400PS and 450NM at the hubs on 1.2bar boost and about 15° Timimg.

But the EGT going very high up to 1100°C on a dyno run(25sec).

EGT messuring point is pre Turbo. One probe showing all 4 cylinder.

I are running right now at afr 11.5

I searched a lot on the internet of what all effecting the EGT. I mean i know timing and afr effects the EGT but i think a run a good afr and a good amount of timing but still getting that high EGT.

The question i ask myself is: is it possible that the Turbo is runing at its maximung and creates backpressure and heaating up the EGT or could be the Injector timing off? OR what else cause this high EGT. Like the Exhaust could not be the problem there as it should be big enough. The AFR should also be spot on or would there be a richer afr better?

I would be more then happy if someone can give me some advice or finding a solution to this problem.

Best

Hans

1 Late ignition angle promotes higher EGT

2 Try to also add some fuel

3 While it is good practice to make the dynorun longer as compared to real street driving, 25 seconds seems very long.

There’s only so much you can do with tuning aside from turning down the boost. Your turbo choice is the biggest factor. That particular turbo has a big compressor to turbine mismatch which causes very high exhaust heat and pressure.

For example the 7064 with 1.05 A/R exhaust housing making the same power would drastically reduce exhaust temp.

The smaller EFR turbos are very skewed towards quick spool, high exhaust pressure and temp.

Unless running a sequential, dual clutch or auto in a standing mile race/high speed run you probably aren't going to be continuously on load for that long are you?

Remember, Mike, it's not just the initial run, but possibly sequential runs with little respite between them, such as may be found on a race track - and both the Autobahn and the Nurburgring are a short drive away.

As has been pointed out, later than optimal ignition timing will increase exhaust temp's because there is more heat energy left in the exhaust, using a MBT fuel ratio may increase the exhaust temperature as it will run hotter than a rich mixture, and a restricted exhaust manifold design/turbine housing will restrict the exhaust flow and hold the heat in them more than a free-flowing option.

Assuming your temperature information is correct - different senders using different materials will give different voltages, so double check you have the right type selected, if it isn't a stand-alone kit - you're going to need to drop the temperature in-line with the manufacturer's maximum. You need to check your specific unit, because different materials, designs, and/or manufacturer's safety marging can make a difference of +/- 150C between them. You "may" get away with running a bit higher for SHORT periods, especially if the rpm isn't pushing the rated maximum, but check for bent or deformed turbine fins regularly.

@DynoDom:

1. yes i do know that

2. Yes i think so, i just have one probe shows all 4 cylinders

3. I already have added some fuel. But will add some more fuel just to try.

4. Its a track only car so i think the car only sees very a load as we want use the car 10 rounds or more flatout. So thenh i think i have e realistic time of run.

@MikeMcGinnis:

That was what im thinking about, i mean when i calculuate the hub hp to engine HP we would be around 450-470hp depends on factor we choice. And that would be pretty much the limit of that turbo. We are planing to upgrade to a EFR-7163 next year. But for now we want to use the current one. Maybe i just need to remove a bit of boost and running it on lower HP for now.

@Slides:

As already mentioned its a full track car need to push 10 or more laps flatout. So The load for the long is not unreal i think. Correct me if im wrong.

@Gord:

Thats exactly the reason i use that long runs. Its a full track and needed to be pushed 10 or more laps flatout.

So you are also on the side of the wrong turbin housing for this application right?

Yes the temp source is correct. I mean the EFR are rated for 1050°C but i dont feal save to run up that high. Would be nice to get it under 1000°C.

25 seconds is a long pull, but I've tuned this turbo on this engine and similar engines, and EGT and EMAP are always something to keep an eye on, especially on gas. I've ended up with a low boost setting on gas and more on ethanol to manage exhaust temps.

My main point is I feel they have reasonable AFR and timing already. If they were 10 degrees low on timing, or leaner, I'd agree that adjustment might make a dent in the EGT concern, but 11.5 AFR and 15 degrees on that engine, turbo, boost and fuel combo is likely within a couple degrees of significant knock, so that's not the path I would take if a change is to be made.

If the goal is to safely make this power level with reduced EGT, I've suggested an alternate EFR to do it, or I can suggest a Garrett G series. Before changing anything though, a few of us have mentioned 25 seconds is a long pull. If you do a 15 second pull, how do things look? What's the longest expected time the vehicle will be at full throttle when in use at the track?

What charge temps are you seeing? If you can do anything to further cool the intake side, you'll see some improvement on the exhaust side.

Just to expand on what Mike has said regarding the ramp run time - It's almost impossible to replicate the airflow you'd see on the open road at the speeds you'd be reaching after 20+ seconds of WOT operation and hence this may be misleading. Have you tested this off the dyno yet to see what the EGT is in real world conditions? For reference I tend to target about 500 rpm/sec for a ramp run (this isn't set in stone), meaning for a typical 2000-7000 rpm run I'm around 10 seconds. I use this for the majority of my tune and then if I have an engine that's very knock sensitive I may finish off with some longer ramp runs to see how the engine handles sustained load and higher combustion temps. This is sort of a torture test and if it passes I can be pretty confident knock won't be an issue on the track/street.

I saw around 750 C peak on the track on our old 86 with the same turbo making 385 whp on 0.85 bar boost but this is on E85. On 98 it is closer to 900 C however due to the fact we ran that car almost exclusively on E85 I didn't quite push it quite as hard power-wise on 98 so it's not a apples to apples comparison. I suspect your issue is probably most likely the ramp run length but it may be worth just confirming 100% that the EGT sensor is reading correctly. The rated max temp of the Gamma-Ti turbine wheels on the smaller EFR is 1050 so you're right at the point of doing some damage if that number is real. I really loved that turbo for our power aims. It felt more like a big capacity V8 than a 2.0 turbo with the boost curve.

Unrelated to your actual question, be careful with 4th gear as they're very weak. I ended up pulling all the boost out of 4th to keep it alive and would then short shift into 5th. If I ran 385 whp in 4th we'd break the box after about 2 race weekends :(

I updated my above post to hopefully better explain my viewpoint.

Honestly if I were you, I'd turn the boost down to perhaps 0.8 bar, confirm you're happy with EGT, then go to the track.

I'd run it like that and see how everything looks, including EGT. If all is well and you have room to turn it up, turn it up a little bit at a time, see what it does, re-evaluate.

If your ECU has the ability to trim boost down as EGT creeps up, that's a great tool.

@Mike and Andre

I just have turned now the boost down to 1.0Bar on the highest map(1. 0.6Bar 2. 0.7Bar 3. 0.87Bar 4. 1.0Bar)

Also reduced the ramp run time to 13sec.

On the lowest map with 300WHP i had a peak of 950C EGT and on the highes map with 365WHP i have about 1050C.

Yes you were right on 1.2bar and 2degrees more timing it startet with small knock.

I wil go next weekend on track and will test it there and will look for the EGT.

I will start ther with the lowest setup and go step by step up and looks whats the egt is making.

For this season i want to keep that setup. For next season i wanted to change anyway to a bigger turbo.

What turbo you would choise here for a power goal of about 500-550WHP? I had the EFR-7163 in my eye but u also know that these also starts to fall off on high rpm. So i also thougt about the G25-660 or G30-660. All in V-Band setup and IWG as i want to keep it simple.

Also with this i will change to a LinkECU and E85.

Ah yes we know the transmission is very weak, for this reason we have a spare transmission that we can change if we breat it. We also will improve it for next season with a stronger gearset.

I wanted to control more safety points but the oem ecu with ecutek allows not many inputs in to the ecu.

Thank you allready for all this answers.

So now i got a bit confused about the EGT Temp reading. double cheaked the calibration.

I have a CANcheacked Display with EGT Amplifier. There calibration with K-Type EGT is 0V = 0°C 5V = 1250°C

But if i look right on the haltech website the K-Type is listed with 0.75V = 0°C 4.5V = 1250°C

So witch one is right? Hope its Haltech, then with them i would be down quite a bit in temps..

Your plan for track test sounds great.

If you're using the CANChecked EGT amplifier and analog output, then you should be using their calibration from voltage to EGT at your ECU.

From the CANChecked website:

Calibration: 0V = 0°C (32°F) and 5V = 1250° (2,282 ℉)Are you running the 5V and ground to the amplifier from 5V supply and sensor ground on your ECU? I apologize, I'm not familiar with that product so if it's all wired to the CANChecked gauge, and data is transmitted from it to ECU via CAN, then HOPEFULLY data error from voltage offset is minimal.

Andre, others, and I will likely all have different thoughts on turbos. For some context on my suggestion, I like Borg for the SXE line in an application that doens't require an EFR/G Series, but prefer Garrett G Series to EFR with their current lineups. I say that because you never know what's coming in the future and turbo tech keeps growing and changing.

I also tend to err on the slightly bigger side in road course applications to reduce temps and improve reliability. From firsthand experience back to back testing several G series turbos including the ones you mentioned plus G30-770, G30-900, G35-900, each step in compressor size does not alter spool characteristics much. G30-660 to 770 is a TINY change in response, but significant in compressor flow per pressure ratio.

I'd say G30-770 with 1.01, make that power with a little less boost than the turbos you mentioned for better temperature control, but that's certainly not the only way, and others will likely have alternate suggestions which will also work great.

Link and E85 also sound good.

You should be able to easily tell by what voltage are you getting at ambient temperature (20-25c)? .81v would be 20c on haltech, and 0.08v would be 20c on the CANchecked Display calibration. Big difference.

So what EGT amplifier are you using? That is what produces the voltage you are using for calibration.

A k-type thermocouple only produces -6mV to 55mV from -270c to 1360c, it's the amplifier that turns this into an easily measurable voltage range. You have to be careful of is where the "cold junction" location is to keep the calibration correct. If you aren't using special pins / connectors designed for k-type thermocouples, then that could put your calibration off.

Yes i use the CANChecked EGT amlifier with Haltech Thermocouple K-Type Sensor and ther CANChecked MFD.

So right now i use the CANChecked calibration. So when the car is cold the EGT is sitting around 25°C and the Coolant / oil at about 15-17°C.

The amilfier is wired with tefzel wire and dtm conncetors to the MFD. So the wiring side should be finde.

yhea i know there a lot of diffrent ideas out there witch turbo would be the best or witch not.

As you mention thats also my idea to choise a slightly bigger turbo for what goal we want so that we can reduce the temps.

I also see the new Turbosmart 5862 Turbo witch also looks guit good but seen no real live data / tests on it right now.

I mean Ecutek is good option but in my opinion for race application you have way to lees options / inputs to the ecu.

So we were testing on the racetrack this weekend. Unfortunately, as expected, the EGT are still very high even with the lowest level of only 300 hp (hubs).

But I have a suspicion what the problem could be. I think the turbocharger should not have any major restrictions at this power level as it is normally designed for up to 450hp.

That's why I thought it could also be our manifold. This one is a 4 in 1 manifold. The 4 pipes each have an OD of 42mm and the pipe in front of the turbocharger only OD of 48mm.

The EGT probe is located just before the turbocharger in the pipe with 48mm (see photo finger).

Is it possible that a backpressure is already forming here before the turbocharger and thus driving up the EGT?

If you want to know how much backpressure there is, you will have to measure it.

Data integrity: Best advice I can give is: purchase a EGT2CAN from Ecumaster and Install four individual probes close to the exhaust valves with a pertrusion of 10 mm.

This is a stanalone system which has personally proven to be outmost useful.

Given that you are measuring close to the turbocharger, the temps you are seeing are reason for serious concern IF data integrity IS confirmed. Considering the very long path for the exhaust gases to travel, you should expect the actual temps near the ports to be significantly higher.

...for what it's worth.

Thats right i should do that. But as mention befor there is no reason that the turbo should make that much back pressure.

I have searched i few hours to get any information on good turbo manifold design and dimension. But found almost nothing.

The only thing i saw is on most manifolds right after the merge collectors every time comes straith the turbo. But on out desgin or alomst on every FA20 or EJ20/25 there comes the merge collector and a almost 30cm long tube thats on most manifolds are about 10-20mm bigger in diameter then the main tubes.

Our was just about 5mm bigger. So we think we had right after the merge collector a big restriction that causes us the back pressure and generate us high EGT.

We now make a new manifold with a cnc 4-1 merge collector right at the turbo. Then we hope our problem is solved.

Thank you for the tipp with the ecumaster egt2can we will add these for next season upgrades.

i will keep you you posted if the problem is solved after the change of the manifold.

Before changing the manifold, I suggest adding exhaust pressure monitoring. Then you'll know if it's an issue or not, and have the sensor for tuning, developing your manifold and turbo setup, and general monitoring.