Subaru Engine Comparison - 6 Cylinder H6 vs STi

[@bujin5455]

Of course, the H6 is doing all of this NA, without the inherent risks which comes alone with boost. You probably also have better throttle control with the NA motor over the turbo'd motor.

[@Brianhopp973]

The H6 curve looks way smoother then the sti I’d think it would be a little quicker on the streets then the sti would be

[@MrHawky-sc6lo]

It would destroy the sti but only because the car is way lighter than a newer sti

[@CreativeCadaver13]

Area under the curve is key in determining which would be the better drive.

[@landontrombley248]

And sound way better in the process 😉

[@inflameswetrust2194]

If the cars are equal weight and equal gear ratios on equal tires then the sti would be quicker. It has a broader power curve. Builds power sooner then the h6 does. The peak power is similar but the h6 is a little behind on the curve until about 6000 rpm. Now if the h6 had any turbo or supercharger on it, even a tiny one, it’d fuck an sti up. Impressive that the h6 is nearly equal an ej207 (or 257 idk which) while running naturally aspirated.

[@YocoWheelin]

I would absolutely prefer the H6. Linear power, and sounds great. May not be as tunable but who cares. I’m sure it’s a hoot.

[@zabnorg]

As a recent swapper to an EZ30 in a bugeye wagon AT and driving an MT bugeye as a daily, this is easily night and day. iWire did the harness and I couldn't be happier with the results. I haven't had a chance to try out a similar vintage Sti for comparison, but I've had plenty of turbocharged cars and they were all a pain in the butt to tune and drive. Torque is all over te place, funky peaks and dips that make it unpredictable in turns. From what I understand the turboed Subies are very unforgiving. I did all sorts of back-alley hacks on my Galant VR-4 without major hiccups (still a pain to tune, but it never self-destructed). I'll take smooth, solid torque FTW. Only issue for me now is the AT, which sucks balls. A shift kit, torque converter upgrade and a mechanical center diff upgrade should fix that, hopefully. For now, it takes off like a turboed Honda, screeching the front tires and going all over the place as the center clutch pack tries in vain to keep up with the torque ...

[@dlorp.]

@@zabnorg I've been thinking about h6 swapping my 97 coupe from it's 2.2l, though I was under the impression that that iWire was no longer doing the harness merge for the h6 which is my main concern of doing the swap.

[@3G4Runner_N_Gunner]

I'd love to do an EZ36 swap in my 95 coupe one day.

[@DosedUpBeatz]

i love this because in my 1995 impreza i really am thinking of a Eg33 or ez30 / ez36 swap into my 4 door GC Chassis, Yea the eg33 requires 3 inch forward Mod of Radiator Mount But For Hp To Weight ratio vs going turbo on my ej18, the 6 cylinder is very tempting and am scouting for one

[@juztinking8813]

The H6 curve is way smoother and flatter, and the car is quite a bit lighter. I also much prefer the look of the older Subaru. The H6 are also super reliable. That is not something that can be said about EJs.

[@roboticunclephil]

God DAMN that h6 sounds good

[@加油台灣-f6m]

Hope more aftermarket parts for ez series

[@roboticunclephil]

These engines seem so slept on

[@TDT0188]

if only subaru had done this from the factory.

[@aarr2603]

Please come out with a kit so we can all do this swap

[@iwiresubaruwiringsolutions5538]

We do in a sense - www.iwireservices.com/six-cylinder-harnesses

[@michaelcliff6574]

To my limited knowledge it's a full bolt in engine. Make sure you do your own research tho 🤣🤣.

[@dennislilly2818]

I would love to do an H6 3.0 swap for my '95 Legacy wagon...

[@taylordve]

Great build. Any advantages/disadvantages with pod filter straight into air intake? Does bonnet scoop help with engine temp.?

[@iwiresubaruwiringsolutions5538]

Most likely a disadvantage due to lack of a plenum box. The hood scoop probably helps keep temps down though.

[@larrybrinley8222]

What about a fair comparison using a power adder on the H6 and put a Procharger on it ? They may be "stock" but the turbo creates a different advantage.

[@iwiresubaruwiringsolutions5538]

I agree, but the 6-cylinder has more displacement to offset the turbo.

[@zeldamaniac3188]

Are there cheap mods worth making to make a EZ36 outback more fun?

[@iwiresubaruwiringsolutions5538]

Not a ton I can think of. Maybe exhaust and intake but that's about it for NA Subaru platforms.

[@jonodevenport6798]

STI has greater area under the curve versus the EZ36, which is what really matter in the real world.

[@shazmaster]

u forgot about turbo lag

[@q2subzero]

Now if someone was looking to add a turbo... or two, to the H6... which H6 engine is better suited for boost? EZ30 or the EZ36R?

[@iwiresubaruwiringsolutions5538]

The EZ30 would be, but that still requires a built block from a company like Outfront.

[@Zanjizan]

Was that a bare bone stock EZ30? /3.6? With an exhaust or what we’re the mods like headers exhaust?

[@iwiresubaruwiringsolutions5538]

All of those details are in the blog post linked in the video description. Take a look and let us know if you have any other questions :)

[@dub537h5]

It's a 3.6l, not sure what the big secret is lol Also that page says "the ez30d from the 01-04 legacy and svx", but the svx actually has an eg33.

[@daveTV]

I don't think this swap would be legal in California though right? You can put an engine that is the same displacement or lower and has to be the same year or newer than the engine you are replacing in the car. You would have to find a work around to get the car smogged and registered in California. Unless the smog guy was clueless. BUT I would think it being a 6 cylinder it would throw a red flag or error on the computer. I could totally be wrong, but it's something to consider. What are you thoughts Brian?

[@iwiresubaruwiringsolutions5538]

Basically no 6 cylinder will pass emissions. Here's a blog post with more details - www.iwireservices.com/post/2018/11/27/6-cylinder-subaru-swap

[@bruceyyyyy]

Good stuff! I swapped the wife's Baja with an H6 last year. Wouldn't ever go back to the EJ25.

[@Tzalmavet]

Step 1: Don't live in California.

[@q2subzero]

doesn't emmissions go out the window when a car is considered an antique? try to find yourself a '95 impreza to do the swap in or something close to the 25 year mark.

[@blackrifle6736]

@@Tzalmavet *Got that right!*

[@andrewrobinson5639]

I'm new to the subie world but I thought stock sti made around 300hp. Once again newbie here

[@iwiresubaruwiringsolutions5538]

300 HP at the crank not the wheels. That's why we used it as a comparison.

[@qoqpop6154]

What manual transmission do you use?

[@iwiresubaruwiringsolutions5538]

6 speed from USDM STi

[@12431dup]

If you were to build this now, what would you do different? I am thinking about replacing the built EJ257 turbo for the N/A H6 #becauseCA #becauseSMOG

[@iwiresubaruwiringsolutions5538]

Great question! We would do what we're doing now, using a 19 STI with stock ECU.

[@12431dup]

@@iwiresubaruwiringsolutions5538 so return the bugeye to stock STI with the twinscroll turbo and stock ecu? #becuaseCAlifornia #becauseSMOG

[@danshady09]

should get a video of the two racing

[@iwiresubaruwiringsolutions5538]

we raced them in the streets of Mexico and the STi won handily.

[@qoqpop6154]

Wow. Help me get that H6 in my Baja , please ?

[@yodad4776]

I have a gen 3 h6 setup with standard ecu in my gen1 gtt bf legacy and it's crazy ..I'm looking at adding 2 turbos and a supercharger and make it stupid

[@deathtoming2201]

Go for gold brother that thing would be the ultimate sleeper ! 🔥🔥🔥

[@yodad4776]

@@deathtoming2201 I ended up selling it .to many cars but I've got 3 good engines in storage still and when I sell a couple more cars I'm gunna do sum more conversions I may have a JDM na Impreza in the pipeline for cheap..all the kit and spottys (looks like a WRX) without the turbo or bonnet scoop ..I've got 2 ez30r and one ez36rr ..(twin vvt)there average 200hp more than a ej when u match like for like bolt ons..it's a no brainer really ej is gone ..lost its relevance to the ez why settle for less power and less reliability when u can have 510hp at 17psi

[@deathtoming2201]

@@yodad4776 your spot on! I have a few cars aswell and one I still have a 99 Impreza rx might be the same car your talking about it’s the na 2l if I had the extra money I would definitely engine swap it.. i did no mods to mine besides catback exhaust and pretty much redline it every day in nearly every gear besides 1st ofc.. has 354,000kms on it 💪🏽 still going strong just needs a good birthday but I was already saving for a newer car to get me from work n back safely ect so got a spec b instead but one day I might get my ass into gear do it up, the two doors go for pretty decent $$$ these days

[@yodad4776]

@@deathtoming2201 what a lot of ppl don't realise I'm seeing in the comments on here is the h6 with no turbo is capable of 400hp atw we have a company here in NZ called NZ performance tuning and for $1300 u can have a 2003-2009 h6 legacy or outback ECU reflash and get 400hp atw on the factory ECU ...factory headers removed cats and bigger exuast and removed intake silence plenum are the only mods required..it's recommend to upgrade the chain tensioners to possum Bourne as they have no anti return on them ..on my 2000 bh h6 I actually had one fail and jumped a tooth ..only took 4 hours to fix it tho ...didn't do any damage ...engine is now at 350kms ..great car ..tows 3.5 tonne

[@jackd1582]

@@yodad4776 Dayum

[@Kuehnpiano]

Ez36 in a frs would be fun😁

[@brandonstratton4159]

Which engine is lighter???? 😉

[@q2subzero]

question is...can all cars that come with the 6cyl be tuned to this power?

[@iwiresubaruwiringsolutions5538]

The drive by wire H6s, yes.

[@q2subzero]

@@iwiresubaruwiringsolutions5538 ah, which cars are those? which years?

[@iwiresubaruwiringsolutions5538]

@@q2subzero That would be 2005+ models.

[@hansyvaldez6211]

I don't why you guys stop making the wiring for the H6 swap

[@iwiresubaruwiringsolutions5538]

EPA cracked down on standalone ECU's so we can no longer wire them up. Standalone ECU is the only way we could get the H6 to work properly with a manual trans.

[@hansyvaldez6211]

@@iwiresubaruwiringsolutions5538 ok,but every state has its own rules and regulations and laws,that's do not apply for all states, California is the most strict of all 50 states

[@iwiresubaruwiringsolutions5538]

@@hansyvaldez6211 Very true, however the EPA is a federal institution so it applies to all 50 states. We're also in California and we want to make sure we can keep our doors open so we have to follow both the state and federal emissions guidelines.

[@hansyvaldez6211]

@@iwiresubaruwiringsolutions5538 like here in NYS and NYC as long as you have all your work documented,all your receipts and car pass all safety and emissions you are all good

[@iwiresubaruwiringsolutions5538]

@@hansyvaldez6211 The standalone ECU wouldn't have a VIN so it would fail the VIN Check during emission in NYC.

[@hermannott7743]

Do you have equal length headers or un equal headers

[@iwiresubaruwiringsolutions5538]

essentially equal

[@dannythompson1948]

Where is this dyno?

[@iwiresubaruwiringsolutions5538]

This was at Metro Performance but they are relocating soon.

[@maykay.jaykayman9647]

Should supercharge the H6

[@Sero12245]

Id go with an h6 swap tbh

[@itsmethough24]

H6 > STI change my mind

[@iwiresubaruwiringsolutions5538]

LOL, well the STI comes as a turbo platform out of the box, has more aftermarket parts, is a cheaper/more reliable build than the H6, the STI fits better in another cars engine bay, and the H6 can not be made emissions friendly in our experience..... I could go on hahah

[@mryony23able]

I think 🤔 6 c is much better then 4.

[@theccwdad]

Who taught you guys how to strap cars down? That chassis shouldn't be moving hardly at all especially at that power 😂😂😂