H6 conversion

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Jun 12, 2003 | 04:34 PM

ZIZZIZ

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From: Mantana, where the men are men and so are the women

Car Info: '03 red legacy

H6 conversion

I have a question, both the Outback and the GC8 2.5 RS have ej25 engines right? and the Outback can come in an 3.0 H6 right? so that would seem that the H6 would fit in the same bay as the ej25 outback. would the same be possible in an RS? how crazy would that be, a blown H6 rs

I know that anything is possible with money, i was just wondering how impossible this is...

Jun 12, 2003 | 05:44 PM

Cabal

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It will fit and it has been done. However, the H6 puts out some pretty poor power for a 3.0L and still requires premium gas, you'd be much better off doing a 2.0 turbo swap and beefing it up (or an STi's 2.5).

Jun 12, 2003 | 05:54 PM

N/A

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How about a turbo Ej25 from the Forester or the Baja?

Jun 13, 2003 | 12:02 PM

EAGLE 5

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Quote:

Originally posted by Cabal
It will fit and it has been done. However, the H6 puts out some pretty poor power for a 3.0L and still requires premium gas, you'd be much better off doing a 2.0 turbo swap and beefing it up (or an STi's 2.5).

Hello I have an H6 Outback Sedan but I have to disagree with your saying that it's a weak engine. Once you hit 4K RPM you're GONE the speed creep from 60-90 is unbelievably fast (not to mention it sounds like a Porsche 911). The only flaw it has is the fact that it's connected to an Auto transmission with lousy gear ratios. I'm not kidding you can go over 70 in 2nd gear very long and very dull at low RPM. If you could only connect the thing to a 5 speed or even the 6 Sti it would fly (add Twin-Turbo and well you know the rest. . .

)

Jun 13, 2003 | 12:08 PM

N/A

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So you can't bolt a 5spd or 6spd to the H6? That sucks.

Jun 13, 2003 | 01:31 PM

EAGLE 5

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Quote:

Originally posted by N/A
So you can't bolt a 5spd or 6spd to the H6? That sucks.

Actually I think a manual is possible to bolt on. I'm pretty sure that the 2002 or 2001 model Legacy Blitzen 6 and some regular Legacy 6's had a manual tranny. I'm just not sure how that is accomplished on an Impreza chassis. Should be very interesting to see if someone does that. I've heard of Legacy Twin Turbo 4's dropped in WRX's with some great results the EZ30 should be promising since the dimensions are nearly identical.

Jun 13, 2003 | 02:00 PM

BlingBlingBlue

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Quote:

Originally posted by EAGLE 5
Hello I have an H6 Outback Sedan but I have to disagree with your saying that it's a weak engine...
The only flaw it has is the fact that it's connected to an Auto transmission with lousy gear ratios.

I think he was talking about the relative power vs. other 3.0 liter 6 cylinder engines. Isn't the honda v6 a 3.0 rated at 240 hp? Not that the H6 is a slouch, just relatively speaking it is not up to the potential that it's displacement suggests.

I test drove an H6 Outback and could not agree more about the gear ratios. It is a fine engine in a fine car with the wrong gear ratios. If it had been mated to a 5 speed (or better yet a 6 speed) I would be driving one of these instead of the WRX.

It has been theorized that modifying the H6 for forced induction would significantly impact it's reliability. The H6 is only half an inch longer than the EJ25. One of the ways they achieved this was to manufacture thinner cylinder walls. This means the block would be less able to handle the additional heat of forced induction. It sure is a nice idea, though. I hope there are some smart engineers holed up in a lab working on this as I type.

Jun 16, 2003 | 04:58 PM

HondaH8er

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Quote:

Originally posted by BlingBlingBlue
[B]I think he was talking about the relative power vs. other 3.0 liter 6 cylinder engines. Isn't the honda v6 a 3.0 rated at 240 hp? Not that the H6 is a slouch, just relatively speaking it is not up to the potential that it's displacement suggests.

You can say the same thing about the 2.5L. The 1.8L in the Integra puts out 170 HP, while the EJ25 puts out 165 HP. The difference is in the torque numbers. If I remember correctly, the Subaru beats the Acura by about 40 lb/ft. Honda's tend to build HP through revs, while Subaru uses torque. Remember Only torque can actually be measured, HP is calculated from that- HP=(torque * RPM)/5252. Just because and engine doesn't put out as much HP as a similar sized engine doesn't mean it's not powerful. I'll take my EJ25 over a B18A any day, just because I like torque down low, and Honda ain't got it. Same goes with the H6; it's got a good HP number, but it has plenty of torque (212 hp/210 lb/ft), while the Honda V6 (at 3.5L) has 240 hp/242 lb/ft, and the 3.0L V6 has 240 hp/212 lb/ft. Dang, guess I shouldn't have looked up the numbers, now my theory doesn't look so good, huh? Oh, well, I'd still rather drive a Subaru!

Jun 16, 2003 | 05:29 PM

Cabal

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I too would rather be driving a Subaru, but the point I meant to make originally is that for a 3.0L 6-cylinder, it's less than what it should be.

Accord: V6 3.0L 240 hp @ 6250 rpm, 212 ft-lbs. @ 5000 rpm on regular unleaded

TL Type-S: V6 3.2L 260 hp @ 6100 rpm, 232 ft-lbs. @ 3500 rpm on premium unleaded

Maxima SL: V6 3.5L 265 hp @ 5800 rpm, 255 ft-lbs. @ 4400 rpm on premium unleaded

Outback: H6 3.0L 212 hp @ 6000 rpm, 210 ft-lbs. @ 4400 rpm on premium unleaded

The middle two have more displacement, but the peak torque is not considerably lower on the Outback than the Accord, and both the TL Type-S and Maxima SL whallop the H6 if you're going to be paying for premium fuel. As mentioned, the the H6 isn't the best for buildups, either. No disrespect intended, but for 3.0L and premium fuel, I consider it lacking (the engine, not the car).