Limp mode after exhaust upgrade

[FT096]

Hey all, new member here.

 

so recently I bought a full 4 inch Xforce exhaust system put into my fg xr6 turbo. after going for a test drive, I realised that my car lost majority of its power. Turning off the ignition and back on was fixing the problem until it was over boosting once again.
I was told that my car needed a tune by friends. Is this the case? And also can I still drive my car on the daily until I get this problem fixed. Engine light is also on now after a day of driving the way it is

[k31th]

 

100% you need a tune if you change the flow characteristics of the air through the engine, especially with an external piece of hardware that uses the flow of air to control it's operation (the turbocharger). Changing the dump and cat is enough to ensure you need a tune. The cat-back by itself generally is OK without a tune. With a full exhaust it will always overboost, hence the issues you're having.

 

You can drive the car, just don't hit boost at all until you get it tuned.

[FT096]

Cheers man! Appreciate the reply

[k31th]

no worries

 

stick around, try the veal

[FT096]

Hey man! So I just spoke to a tuner from melbourne, and he told me that I’m going to need bigger injectors, modification on the turbo and a bigger intercooler + a tune to fix the issue. am I being told the right things here?

[k31th]

he's probably just covering his butt plus a little bit of upsell there...

 

bigger intercooler is 100% NOT necessary, but does make your power application repeatable.

 

injectors are definitely NOT necessary; stock injectors can handle the setup you have, but are necessary for higher specific power goals.

 

the modification on the turbo, which is a porting of the wastegate and a bigger actuator/flap may be necessary to correctly control boost with the bigger dump pipe/cat etc in there... but again, isn't strictly necessary.

[FT096]

A lot of people try to upsell..

 

I only have a turbo side intake and the full 4inch system running on my fg. I trust your words 100% and won’t be changing those then, just the tune and bigger actuator to control the boost as you said.

im happy to be getting close to 300 at the wheels tbh, I’m not planning on going for a big setup, that’s why I don’t want to upgrade any unnecessary parts, just want to fix the problem I’m having

[k31th]

300 at the wheels will be a struggle with stock FG XR6T injectors, but FG F6 injectors can get there.

 

you can easily fix the problem you're having by putting the stock exhaust back on haha, but of course the upgrade path is better (but also more expensive, of course).

[El Andrew]

I'd be inclined to go injectors for 300ish - factory ones will be absolutely maxed out and you want a bit if a safety margin.

 

However as Keith says, you can absolutely get the car tuned for that exhaust (within the limit of the factory injectors).

 

What is happening now is that you have made it easier for the turbo to make boost pressure by improving the exhaust flow. The car is sensing that boost is higher than it expects and so is cutting the boost, hence the power drop. The tune will allow the car to make a bit more boost, plus revise the overboost cut settings.

 

If you pay the little bit extra now for injectors, you will get a much better result from the money you are spending on the tune. If you do the injectors later you will need to pay for a tune again.

 

You can upgrade the intercooler later without needing another tune.

 

The wastegate flapper and port seems to be needed in some cases and not others. Mine is fine with a 4" dump and cat, but I still have the factory cat back.

 

Might pay to have a chat to a few workshops too and have a read on here about who is recommended. Pitlane seems to be the go for most Vic people on here.

 

Edit: was typing while Keith was typing. That's actually exactly what I did - my car was making 300kw on stock injectors when I got it, and I replaced them with F6 injectors.

[rtslbd]

As the others have said you will need a tune to drive with a replacement dump/cat. I'm running the full venom system and didn't need to replace the actuator or do any mods to the turbo.

 

If its within your budget definitely get the injectors done at the same time you won't regret it.