Subaru motor; can it make an endurance race reliable 400 whp?

As stated, can these make a 24hr race reliable 400 hp? Don't care what combo/configuration of parts is needed. Don't mind spending a bit to get the right parts as well for my assembly. This will be mated to a converted and beefed FWD for RWD transaxle which are claimed to be good to 700 by some (OK, is that true?).

I really think I'm going to do this

I'm horrendously biased against Subaru engines. I know a bunch of people that have blown them up. Some that rebuilt them and blew them up again.

I'm going to say yes as subaru has won the 24 hours of Nurburgring:

Some car info

race highights

Not sure what all they did but they have won it the last 2 years.

I watched a pro-am team attempt 2.5 hour races with closer to 500hp. 9 times out of 10 it was a dnf. When it held together it was a beautiful thing.

I would find another idea, personally.

If "I don't care" is the budget of course it's possible. You might as well simplify the question by asking if the block can hold 400hp for 24 hours, which I'd imagine it can. But I get the feeling this is not truly a money-no-object build, or you wouldn't be asking here...

I can't see why it couldn't be done.

Can a h6 be fitted? The outback h6 is 217hp stock n/a, so not a bad starting point.

If it has to be 4 cyl Ej22 has seen 280hp in standard trim in turbo applications and the ej25 has seen 320 in factory turbo applications.

You'd be looking at how to keep engine temps down, prevent oil starvation, and making sure the tune is reasonably safe in terms of fuel ratios and ignition timing.

Phil published an article about cars that seem like a good choice for lemons racing but always fail.

Subaru was prominent on that list.

Nearly anything with a turbo is a bad idea in endurance racing. Turbo Subarus are generally a very bad idea.

If you can afford to build a fresh motor for every event, it could work. Otherwise, not so much

Closed deck 2.2L is the answer. North American spec factory turbo EJ motors are not.

Either that or get really familiar with custom oiling solutions.

This website has a lot of nice stuff that would seem to make 400 hp no sweat, but it's spendy.

Modern Automotive Performance

In short, no. I consider myself a "Subaru guy" but...

Subaru makes a good engine for an economy car with awd. Its a cheap tight package that is smooth and pretty efficient.

For racing though? The cooling system is good. The bearings are wrong. The oil pump is wrong. The oil returns are wrong. The unequal length runners to a high mount turbo is wrong. The fuel rails are wrong. The fuel pressure regulation is wrong. The intercooler is wrong. The engine management is wrong(more like stock engine management is garbage). Hell, the wheel bearings and hubs are wrong on everything but the sti, and on the sti they are just okay. The suspension is wrong. The 6mt is the only good transmission but it is poorly geared.

I don't know why I keep going back to those stupid little cars.

In reply to Ojala:

Indeed.

I'd look into what Porsche engineers did to make the aircooled flat-six such an endurance racing powerhouse. They did a very good job of starting with a bad idea and making it work. (Mostly, cooling and cooling and cooling some more, planning to make twice as much power as you ned and then derate it) So, I'd say make an 800hp Subaru engine, with everything needed to make 800hp sustainably and not in several second bursts, and then only make 400hp with it.

Knurled wrote: In reply to Ojala: Indeed. I'd look into what Porsche engineers did to make the aircooled flat-six such an endurance racing powerhouse. They did a very good job of starting with a bad idea and making it work. (Mostly, cooling and cooling and cooling some more, planning to make twice as much power as you ned and then derate it) So, I'd say make an 800hp Subaru engine, with everything needed to make 800hp sustainably and not in several second bursts, and then only make 400hp with it.

So, a Subaru GRC engine with the boost and revs turned down Hey, you're willing to spend right? Where's sachilles?

I'm curious what endurance race you are planning to run with this

This is for the 935/936 replica car I'm kicking around. As far as where it would run, that's a bit of an open question. It would legal for GT (the rules are pretty wide open) in ON and might be allowed in G70 as replica but those are generally 30-180 minute races. The endurance race requirement stated by me is more philosophical; but who knows. I'd love to run a 24 hr race in something like that if I could find a venue.

And to hint at budget, yes money is a consideration. If I could build something like this in 2 seasons and spend under $20K excluding my labor, I think I'd be happy with that. Using the accepted rule from the Locost forum, that means $40K; maybe I should have said $15K ;-) But this is an ever evolving idea.

Having blown up 4 Nissan KA24DE's in one season, I am now of the opinion that low horsepower and reliable is the way to go. Funny how I was told that but had to learn it myself anyway. You can make it work but then you are an engine builder first, a re and re specialist second and a race car driver WAY down on the list.

The disadvantages of the EJ25 are cylinder wall strength and piston strength. And block strength. The aforementioned closed deck EJ22s (and the closed deck EJ20s) while rare and prized, solve the cylinder wall strength and the smaller bores and shorter strokes help the piston strength. Less stroke allows more piston pin height. Smaller bores are also more detonation resistant, allowing you to crank in more boost under the same conditions, or have more safety factor for the same boost.

Notice that the Fx-series engines have smaller bores and longer strokes than their EJ counterparts, this is not just for fuel efficiency. (I didn't measure but it appears they have much more pin height than EJs despite the longer strokes. EJ20s are extremely oversquare like ACVWs but the modern engines are 86x86)

The flat-six cranks scare me for how spindly they look, I wouldn't bother.

Personally, and maybe this is heresy, but for the money you'd put into making a Subaru engine reliable at 400hp, let alone 400whp, it may be cheaper in the long run to source an actual Porsche turbo engine...

GameboyRMH wrote: So, a Subaru GRC engine with the boost and revs turned down Hey, you're willing to spend right? Where's sachilles?

Oddly enough, when talking turbo engines, for the same horsepower level, revs are life and boost is hard on parts. When you want to make power over a long period of time. There's less heat in revs and heat will be your main enemy.

With your given budget I think it would be cheaper in the long run to just build a Porsche engine. They're more reliable and durable.

LS motor for half the price, twice the life

Get a version 7 sti engine or build an equivalent.

That being said if you want a cool japanese engine that is proven in endurance racing you probably should look at a RB26

If you take care of the oiling issues (which on a RB26 are like 9/10th the way there compared to RB25) you basically have one of the most proven engines there is for this kind of racing.

400hp is about where RB26es are no longer reliable (scroll down).

Is the target 400 @ the crank or wheels?

A lot of the responses in this thread are regarding EJ motors. Would the FA motors be better for this application?

For $20k I'd think the bottom end issues could be solved, as well as the block issues (just buy a closed deck block).

GameboyRMH wrote: 400hp is about where RB26es are no longer reliable (scroll down).

I love Moto iQ tech (I wish GRM would do similar pieces). Their blog layout is miserable though :(

Edit: link for last page of that same article where the EJ257 appears: linky

This is a very bad idea.