Antilag and Turbocharger

Hi

I have to built a new turbosetup for a Group N Impreza GC8. The car is equiped with a second air injection system, which feeds air direct in to the exhaust. So it's a pretty serious Antilag system. The car doesn't run anymore Groupe N, so we are free with modifications and turbo choice.

I've got some questions, which maybe someone with more experience on Antilag can answer.

Hardware side

- Which bearing desinge last longer? Ball bearing or journal bearing?

- Are there any things where you shoud pay attention when you choice a new turbocharger for Rally Antilag?

- Has anyone expierience with BW EFRor Forced Performance Turbos with Rally antilag?

- suggestions for Turbos, we are aiming for 400-450PS (300-330kw) @ flywheel.

ECU side:

- are there any special things where you have to pay alot of attention?

- What are the highest EGT's you should see during Antilag? I suppose not more than under WOT?

- I think, setting up an EGT input which powers the Antilag down if temperatures get to hot, are well worth, isn't it?

Thanks in advance for answers!

Hi Adrian,

We're actually part way through an Antilag course which will probably be ideal for you when complete. However for now, here are some tips:

1. A ball bearing turbo is superior for strength to a journal bearing turbo, particularly in thrust loading which is important if you're going to run an aggressive antilag strategy.

2. The turbine wheel and turbine housing will take a hammering with antilag so material choice is important. I've seen the exhaust housings of some turbos literally sag and distort due to the heat caused by antilag. It's difficult to apply a blanket rule, but generally quality name brand turbos are going to be a longer lasting option than many of the cheaper turbos coming out of China. If you can get some hard data on the maximum temp capability of the turbine wheel then this will be helpful but I'll admit that isn't always as easy to find as you'd expect.

3. I've had no experience with the FP turbos and antilag, however our 86 (which I'm using for our antilag course) has an EFR turbo and I discussed how well the EFR would handle antilag with Geoff from Full Race prior to getting started and confirmed they were up to the task. If you plan to push an EFR hard, it would pay to add the speed sensor kit as over speeding them is one sure way to destroy them.

4. It really comes down to your turbo preference as there are undoubtedly a number of turbos that will support that sort of power on an EJ20. You haven't mentioned fuel either which has a big impact on power capability. Subaru engines don't spool turbos particularly well so you do need to be careful with your choice, although clearly the antilag will be beneficial here. If it was me, I'd be seriously considering something in the EFR family. The 6758 I'm using is probably a little marginal to go far north of 300 kW atw, but the 7163 or the 7064 are both viable options.

5. When it comes to EGT, the lower, the better. Most turbos won't handle much more than around 950-1000 deg C for sustained periods so you can keep this in mind. If you're using E85 this will help your cause. I would always recommend including an EGT input with an antilag system where possible.

Hi Andre

That's a really good and helpfull answer, thank you! Also great to hear that you will make a course on this topic.

I'm a big fan of the EFR Turbos and I would really like it to use such an unit. Unfortunately the customer want a stock location Plug and Play Turbo for now, which he also can use later, when we rebuilt the engine in a year or two and things get serious. What I'm know there are no Subaru Plug and Play EFR Turbos available? Maybe just another uppipe for the EFR would be an option if that is available? Unfortunately the Full-Race Kit is out of the customers budget.

The car will be used for snow rallys, so it will see alot of of load for long times. My thought was that a bigger turbo that runs on low boost to make the power would hold the stock block better together than a littel one which we have to squize out to the last bit to reach around 350PS @ Flywheel for now.

Maybe we should forgot the idea to buy now a turbo that will also work for higher power on the built engine in 1,2 years. What's your oppinion?

I personaly had alot of troubles on a SR20det with high EGT. Garett says that their turbos can withstand 950°C. The GT2871r has seen over 1000°C several times and regulary up to 1000°C wihtout failure. BW state that the EFR-Serie Turbos will withstand 1050°C. I don't have data from IHI. Maybe someone other?

We will using V-Power 100 octane fuel for know. Later maybe E85, but I have a bit respect if the car will fire up on regions where we see -20°C or colder outside temperatures.

I'm sorry to bring this back, Andre. Did you happen to finish the anti lag course? I found webinar on topic, but if there is a course I would like to buy it, as it will be much help at the moment. Thank you in advance!

Hi Hayden, sorry we actually parked development of that course. It's quite likely we will complete it in the future but I can't give you a solid date sorry.

Ahh OK. Alright, I'm dealing with my own drift car, running an EFR turbo. I do have 50hp dry shot nitrous just installed. I'm split between using the nitrous as anti-lag , or traditional rally style ALS (DBW for air bypas). I have not used either of them so far, so no experience, but if I can have your opinion on this it will be great. Thank you.