ultimate rally-x engine

Imprezah said:
EJ25 with STI rods

custom pistons for 9.5:1 compression ratio

EJ25 SOHC heads with cams and a port job

TD04 or 16G turbo

run it off of a wrx ecu, wiring harness, and intake manifold

maybe add meth and open source tune it
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This is along the lines of what i'm thinking for autox engine in the RS someday. Tones of torque with super early spool.

The phase II 2.5 NA makes so much torque, esp with borla headers and catback. Couple that with removing lots of weight i don't know if any turbo would be any better. I haven't rallyxed... but would turbo in such a lite car be too manic for rallyx vs higher speeds of rally were turbos seem to shine?

I like the 4.44 silliness for the GO NOW! factor. Really want to ride in a GC with them!

 
what about an EG33?

how much extra weight does the H-6 add over an EJ25?

I suppose it is a compromise between lotsa extra low end torque and more power across the range versus more weight in front of the front wheels.

 
according to elliseast, who has had an eg33 swap in a gc era impreza for awhile now, it is VERY fast. he says the amount of torque it provides immediately is amazing.

 
Imprezah said:
<br />what about an EG33?<br /><br />how much extra weight does the H-6  add over an EJ25? <br />I suppose it is a compromise between lotsa extra low end torque and more power across the range versus more weight in front of the front wheels.<br />
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a buddy has a 4-door GC rally car with the H6 swap....its got bags of power in a straight line but the added engine weight over front wheels has led to some struggles with understeer. he's made some suspension tweaks and improvements but the car is still a piggie in tight twisties.

 
h6 is for the exotic tinkering street, gentle...the sound alone sells it.

racers need a long manufacture run of a common EJ...is that the 2.5 liter now?

cheaply expendible everything is the ultimate.

I'd still tackle an EA for rally before an H6...
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ahhh yes....

as much as we all agree that EA engines are far superior in every way.... it would just be too much trouble swapping one into an impreza.

 
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I saw elliseast with his eg33 gc obs at the winter rallycross last year. That thing had serious nuts. It was him vs rezpunks 02 wrx all day.

Interesting to hear your buddy's impressions with an H6 Nigel.

I've debated what I should do with my RS, turbo swap, H6 swap, keep the boring 2.5. Right now reseal/repiston/rebearing my 2.5 is in the lead.

A guy on my other messageboard is swapping in an ez30 into his impreza and I'm anxious to see how it goes, right now he's stuck on fooling the computer to mate it to a 5 speed instead of an auto.

 
so does anyone know just how much more an EG33 weighs compared to an EJ25?

If it is only say, 75lbs, that could be made up for by relocating the battery, removing A/C, JDM bumper beam, and carbon fiber hood.

 
Imprezah said:
so does anyone know just how much more an EG33 weighs compared to an EJ25?

If it is only say, 75lbs, that could be made up for by relocating the battery, removing A/C, JDM bumper beam, and carbon fiber hood.
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Found this on an aviation website (obviously weight is crucial)

EJ-25: 2,5 liter, 165 to 200 hp, about 135 kg dry weight (297lbs)

EJ-33: 3,3 liter, 225 to 275 hp, about 160 kg dry weight (352lbs)

 
great thanks,

adding 55 pounds in front of the wheels is not a good thing, but you can compensate and bring the front weight back to stock and still handle like a EJ25.

So is the H-6 the best rally-x engine!?

 
I wonder about the EG33 vs the EZ30.

If you go ez30, you don't have to move the radiator around so it seems, but you have to do more wiring dickery. I wonder if that weight is further back than an EG33 would be.

I think you could use suspension adjustments to dial out some of the extra weight from the H6 along with relocating stuff, it's just a matter of how much.

 
one question ppl often overlook when thinking motor swaps for race cars is what are the classing ramifications of the swaphave kinda lost touch with current rallyX regs, but am pretty sure you can keep a 'stock' motor and make all sorts of suspension and chassis tweaks without getting kicked up a class or 2 so you're running with what are basically Open Class rally cars.

am still of the inclination that for rallyx the motor itself makes much less difference than lightness, agility, simplicity and mechanical reliability.for the time and $$$ and mechanical uncertainty involved in an H6 swap, you can do considerable wonders to stripping  your car, bolting on supple longer-travel suspension, fitting lower/closer ratio gearing, center/front/rear LSDs and proper tires.....all of which you;d need to do on top of the H6 swap to be competitive anyway.

Colin Chapman of Lotus built cars that won many races with the mantra, "simplicate, then add lightness."

 
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Mark said:
<br />Found this on an aviation website (obviously weight is crucial)<br /><br />EJ-25: 2,5 liter, 165 to 200 hp, about 135 kg dry weight (297lbs)<br />EJ-33: 3,3 liter, 225 to 275 hp, about 160 kg dry weight (352lbs)<br />
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hrmmmm....that's less of a difference than I thought. add in the difference of bigger rad for H6 and the gap gets a lil bigger

even so, 60 lbs is the same as 10 gallons of gas -- which ppl often race with this much gas aboard to avoid fuel starve issues.

this is half the weight of even a lightweight passenger -- which ppl typically carry to give their buds some thrill rides

the right wheel/tire combo would save at least half that 60 pound penalty, etc etc

guess what I'm saying is that there are lots of ways to save weight that a majority of rallyX racers fail to take advantage of.

 
ditching the steel hood for the alum or cf one would be a big saver like imprezah said. I'd have to venture a guess that would save in the area of like 20-25 lbs alone.

 
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