GR Yaris Inconsistent Boost

[warren_RS3]

I had a similar issue to this on another car. It turned out to be a traction related issue. If there was any traction issues the cars default position was to cut the boost. The car ran very high tyre pressures and had staggered tyres, neither of which helped, and seemed exacerbated if there was any steering angle. If I turned TCS off fully it almost completed remedied the issue. It can be so difficult trying to pin these issues down to a sensor, a mapping table issue or operating anomaly. I’m not saying it is this issue, but just widening the points for consideration.

Ideally if someone could log boost requested vs actual, see whether there is any timing pull, and monitor whether any sensors are operating outside of expected values it would be a good starting point. No known issues with diverted valves holding pressure like on the VAG early valves with rubber skirts?

 

[nails84]

There must be a way to log and see if the ecu is actually requesting lower boost(and why) at that time or if it just doesn't build boost for some reason. But I guess nobody has done that, or complained to Toyota because there seems to be no answers. Mapping would definitely help if the problem is not in the hardware and if they actually have full control over the ecu. I hope Toyota fixes this, it's not normal to feel major inconsistencies in power delivery when you're just occasionally accelerating on the street. It's normal to loose power when the engine protection protocols kick in, but not like this IMO. I don't have my car yet, this concerns me a little bit. Are there people who don't have this issue?

I have had my GR over a year and from new and have never experienced this issue. My car is totally stock.

 

[Onehp]

No known issues with diverted valves holding pressure.. ?

Good point, another possible source of (intermittent) boost leaks.

As for actual failure rates, manufacturers of aftermarket recirc/dump valves seem to have a standard text suggestion that many OE ones fail, even though the platform was very new when their products launched. It could be, when the recirc opens its quite vocal so one perhaps could hear leaks if one is listening for it?

 

[amarce]

Not sure running camshafts on stock ECU is a good idea... Unless they are very close to OE spec...
I hope you have a good tuner that remembers who you are after you pay him otherwise can become expensive

I've talked with kellfold cams and they have one cam that has a little bit more lift and a little bit more duration, and they told me that this is for the OEM ECU and OEM map, so will try those. My tuner is 100% trustworth (And I'll have an invoice, so he should remember )

 

[amarce]

I have had my GR over a year and from new and have never experienced this issue. My car is totally stock.

It has never done it to me, I've pushed it super hard, but the other day, while sitting on traffic (Hot day, with super hot engine), I've done a 1st gear pull to change lane and it happened for the first time, after a year of having the car. It seems a overboost, because the car pulled harder than ever for sure is an unexpected boost spike and the ECU does a "limp" mode to prevent another spike and break the engine. I'll check if I have any error code so I can see the freezed frame and tell how much boost was there.

 

[Michael Knight]

I've noticed this when driving 70-80% so semi spirited - occasionally car was boosting less so throttle response was bit off to the overall feeling.
Felt that car didn't know if it was supposed to be going faster or not so decided to give less boost. but hasn't happened many times.

 

[Mintmansam]

I've talked with kellfold cams and they have one cam that has a little bit more lift and a little bit more duration, and they told me that this is for the OEM ECU and OEM map, so will try those. My tuner is 100% trustworth (And I'll have an invoice, so he should remember )

Surely if it’s close enough to not require a remap, it’s not really worth it? You’ve also completely lost the warranty on the engine as well?

Personally I’d get them installed and a remap or leave it

 

[Duke]

Surely if it’s close enough to not require a remap, it’s not really worth it? You’ve also completely lost the warranty on the engine as well?

Personally I’d get them installed and a remap or leave it

That was my thought too.

 

[Onehp]

That was my thought too.

@Mintmansam
FYI aftermarket cams are a bit more secure for high power esp. with stiffer springs, as OE has the lobes pressed on only.

 

[warren_RS3]

Just a thought here, and before you think I'm being holier than thou, to be clear I've remapped every car with an ECU I have ever owned since the early 2000's, so I'm not trying to be a righteous pr**k.

When you read the online Gazoo/Yaris literature a few things strike me:

1) the most powerful 1.6 litre 3 cylinder engine in the world
2) the lightest engine of its kind in the world
3) its a first generation engine, that means due to speed to market we are the guinea pigs
4) being an early adopter means taking the pain

So based on the above, what seems logical?

It's the most powerful 1600cc 3cyl in the world (ergo, there's not huge amounts of headroom in the standard set up). Yes, meeting Euro6 will have created some margin for exploitation, but not much

It's the lightest. Light means lighter materials, thinner walls. You gain a benefit in lost weight, but the risk is the block may have less margin for increased operating conditions. It may actually be safer to go big turbo than overboost the factory one

Does Toyota use this 1.6 in competition in a modified state. If yes, they know it has a safety margin. If no, and i'm sure the rally cars use a 2.0 litre, then this limits confidence. We need to see what's been done to the Corolla lump and copy that fir starters rather than assuming bolting on a raft of half thousand pound mods are the golden ticket.

Finally, all the above are a huge inconvenience for tuning companies. They might test on a dyno for a day or two, but what extended real world testing do these products actually get? And on what fuel types? Being first to market is lucrative, but consider why do many products see v2/3 after a few months from launch.

If you don't mind being an early adopter then ignore all the above, and thank you for supporting our wider learnings. For me with this car I'm going to watch in the wings for a while in case Toyota find internal issues that require rectification, then they can't refuse fixing it under warranty. I'm not saying don't, I'm just saying choose a reputable tuner and don't default to the egotists view that more power is always the easiest answer.

 

[Risu]

Does Toyota use this 1.6 in competition in a modified state. If yes, they know it has a safety margin. If no, and i'm sure the rally cars use a 2.0 litre, then this limits confidence.

Yes. See Rookie Racing Yaris, and AP4 Rally Yaris. This engine has a lot of room for power with just valve springs, see Motive Yaris.


Those with boost issues, can you try logging KCLV and Knock feedback? Timing/boost might be getting pulled due to knock. They're both available to log in obdfusion.

 

[Benj]

Yes. See Rookie Racing Yaris, and AP4 Rally Yaris. This engine has a lot of room for power with just valve springs, see Motive Yaris.


Those with boost issues, can you try logging KCLV and Knock feedback? Timing/boost might be getting pulled due to knock. They're both available to log in obdfusion.

I've just ordered a OBDLink MX+ so I'll probably be able to check early next week.

 

[amarce]

Surely if it’s close enough to not require a remap, it’s not really worth it? You’ve also completely lost the warranty on the engine as well?

Personally I’d get them installed and a remap or leave it

Well, we know that this engines will not blow up; and toyota does not solve this kind of problems either, so maybe is better take your own route sometimes

 

[amarce]

Yes. See Rookie Racing Yaris, and AP4 Rally Yaris. This engine has a lot of room for power with just valve springs, see Motive Yaris.


Those with boost issues, can you try logging KCLV and Knock feedback? Timing/boost might be getting pulled due to knock. They're both available to log in obdfusion.

There are some of them with 500HP being constantly abused on racetracks. The “only” weak point at the moment are the valve springs and head gasket. Regarding the Corolla, only has more boost and people are saying harder valve springs, so go figure

 

[amarce]

Yes. See Rookie Racing Yaris, and AP4 Rally Yaris. This engine has a lot of room for power with just valve springs, see Motive Yaris.


Those with boost issues, can you try logging KCLV and Knock feedback? Timing/boost might be getting pulled due to knock. They're both available to log in obdfusion.

No knock for me, what I saw is that when the ingested air is cold, it prefers timing advance vs boost, and it keeps trying to advance timing vs adding boost and car has less power. Sometimes the boost rises and goes down constantly and the timing does the opposite, I think that is a bad map for sure

 

[Tralien]

Corolla has better valve springs? So you could use these to go above 1.6 bar in the Yaris? Could be nice to use stock parts from another Toyota model

 

[Onehp]

Corolla has better valve springs? So you could use these to go above 1.6 bar in the Yaris? Could be nice to use stock parts from another Toyota model

They will be good for 300hp? If going anywhere near 1,6bar, better with aftermarket springs and cams....

 

[Tralien]

300 hp sais nothing about boost maybe the corolla also has 1.5 bar boost and gains the additional hp elsewhere. Like n/a tuning
I think our boost problems are boost related, independent from hp. Maybe if the new corolla came out and ecu is cracked, we will see how far you can go without valve float.

But if someone already knows.....I would be interrested in changing valve springs

 

[Onehp]

300 hp sais nothing about boost maybe the corolla also mhas 1.5 bar boost and gains the additional hp elsewhere. Like n/a tuning
I think our boost problems are boost related, independent from hp. Maybe if the new corolla came out and ecu is cracked, we will see how far you can go without valve float.

But if someone already knows.....I would be interrested in changing valve springs

What matters for valve springs is boost near redline. GRY is about 1,1bar there. GRC will be 1,2-1,3 bar then, depending on how 10% more boost is defined. So still far below 1,6 bar and what kind of margin of error is there on that number? How about aging?

And practically, how would you even source GRC exhauat valve springs?

 

[Benj]

So I bought a OBDLink MX+ and have just been waiting for the car to play up so that I can log it. Today I managed to log full throttle with the issue. Timing advance seem to be ok and commanded/actual boost are within 1-2 psi of each other but around 7 psi lower than it should be. Below is a link to the log. Maybe someone else will see something in the data that I can't.

datazap.me | benj | Log 1652770899

datazap.me