Ideal carburettor for EJ25?

[Phizinza]

I'm wanting to put a carb on an EJ25. What do you think would suit best?

 

Without custom manifold I'd probably have to do a side draft, but thinking it might just be easier to make a manifold and use a weber or holly? What models do you think would suit a 2.5 litre flat four?

 

Cheers,

Phiz

[apintonut]

Side drafts have been done

[TOONGA]

Check my thread on AUsubaru http://www.ausubaru.com/forum/showthread.php?t=15851&page=24

 

I have an ADM34 (ford weber)  on an EJ22 it is a progressive 34mm twin barrel rejetted with a 130 main and 135 secondary (I think) with 50 idle jets. I did use a 32/36 weber for  quite a while but foud it lacked low down power when i went off road.

 

The manifold is from an EJ16 motor http://www.ausubaru.com/forum/showpost.php?p=141108&postcount=18 the plenum was cut flat and an adaptor plate was welded in place, I originally had a 320 holley on the motor but it was way too rich and well a holley

 

I use a lucas dizzy and matched coil (very important) from a ford escort as it is way shorter than the MK3 dizzy for ignition http://www.ausubaru.com/forum/showpost.php?p=169848&postcount=627

 

I get 8 litres to 100kms on the highway 10 to the 100 in town and lots and lots of power off road

 

 

Good luck with it

 

TOONGA

[Phizinza]

Thanks apintonut, looks like down drafts to me though..? One on each head style?

 

Thanks Toonga, will have to look more through that thread on the laptop, phones a bit cumbersome.

 

What troubles did you have with the Holley? I'd like to run one because of the low profile nature of them.

[monstaru]

The 34/34 from some old Fiats works pretty well, I did a 32/36 with an RAF custom manifold.

I could not get the clutch to catch so didna ever drive it.But it ran GOOD.

cheers

[ivans imports]

650 holly 4 barrel into a big turbo into intake have seen a ea82 na with 4 barrel rx7 carb worked well reved to 8500 was neat trick

[TOONGA]

Phiz the holley was a 350 and even though I rebuilt it and re jetted it to suit the motor, it would flood off idle then when it finally ran it was all power and no controlability. I even had a whole array of cams for the acelerator pump but none made a difference.

 

If you can find a SPFI or carby manifold  like the one shown here http://www.ultimatesubaru.org/forum/topic/108209-ej-fsm-carb-info/?do=findComment&comment=912770 (get me one as well) it will go a long way to lowering the profile of the whole set up.

 

your other alternative is a custom manifold.

 

TOONGA

[Phizinza]

I think it's going to have to be custom manifold to get what I want. That's ok, shouldn't be to hard to make.

The Holley website suggests a 390cfm carb for the 2.5l... strange you had flooding issues.

[Phizinza]

Oh, and that port on the intake is tiny!

[NorthWet]

I think it's going to have to be custom manifold to get what I want. That's ok, shouldn't be to hard to make.

The Holley website suggests a 390cfm carb for the 2.5l... strange you had flooding issues.

I had the Holley 390CFM on my 1971 Datsun 510 ("Bluebird") with an L20B engine.  I had previously had a pair of Weber 40DCOEs (which gave me nothing but trouble), and the 390CFM was far superior for street use.  MUCH better fuel mileage, great driveability, and good power.  It was also MUCH more expensive than the average Holley 4-barrel.  Engine vibration ultimately destroyed an auxiliary venturi.  Sigh. 

[Uberoo]

WHY?

[Phizinza]

Many reasons.

[Uberoo]

Engine noise is the only thing I can think of a carb can do better than FI.

[Phizinza]

When i get on the computer I'll explain my reasons...

[TOONGA]

Not strange I had flooding issues with a 320/350 holley as they are designed for 3 litre plus motors eg big 6 cylinder motors or small V8 motors even my ADM34 is a stretch on a 2.2 litre motor.(let the arguments commence:) ) for what I wanted the holley was overkill, it was free and I ended up spending near 150 dollars on it which included the cams, rebuild kit, a new power valve (suited to the engine) new jets (suited to the engine) and countless hours of trying to tune it so it ran smoothly, I gave up and sold it for what cost to rebuild it.

 

I was looking and still am looking for a way to have a daily driver that isn't too expensive to run but still fun off road, without having to cut down a loom and find somewhere to hide an ECU so it doesn't get destroyed.

 

In the end it depends on what you are going to do with this motor what car/ buggy it will go into and how often it gets driven.

 

As for the SPFI or carby manifold the inlet woud be machined and welded to suit a weber design.

 

As for the EFI over carby dizzy setup ... I won't get into which is better because both have their good points and bad points.

 

TOONGA

[Quidam]

Engine noise is the only thing I can think of a carb can do better than FI.

Ha. I can make more power with a carb than most can make otherwise. Trust me.It's simple. For less money.

 

Doug

[Quidam]

four barrel all you want, I can take a 2300 two barrel Holley and run rings around that setup. It's single inlet, center pivot floats, metering blocks...and ment for a bigger engine than 2.5. The 2300 has the pedigree of a champion. Parts galore to do what ever you want to one. Race proven.

Edited September 22, 2013 by Quidam

[Quidam]

 

Single inlet, tube to seconday bowl...do you believe you'll need the capacity of fuel contained in those two bowls? Side pivot floats, I don't like them in a carb like this....In short, this carb isn't a HP carb.

 

Doug

 

Edited September 22, 2013 by Quidam

[Phizinza]

I had a Holley similar looking to that a couple of years back off of a Rover 3.5. Sold it though. Forgot what model it was. I'm looking to also run LPG through a ring on the intake.

 

I'm not incredibly carb savvy, what do you mean by fuel contained in the to bowls? What would this be for?

[ivans imports]

rx7 4 barrel

[Phizinza]

Looks like a incredibly complicated carb, nothing like the simple layout of the Holley's

[ivans imports]

mabee a big SU or two of them if you like simple can be tuned with oil weight

[Uberoo]

Ha. I can make more power with a carb than most can make otherwise. Trust me.It's simple. For less money.

 

Doug

The EJ25 is already fuel injected so converting to a carb costs money.Not to mention all the tuning issues with a large carb or multiple small carbs. Not to mention the immense popularity of the subaru engine means than a computer can be cheaply ordered for any power level you want. One advantage to carbs is it is much easier to run LPG which might be why Phizinza is interested because LPG is much cheaper than gas.

 

To truly make power with a 4 cylinder engine it requires boost of some sort,Carbs SUCK for that. You can make power without boost but it usually means ultra high revs.If you claim to be able to make power post some pics and videos of 2-2.5L engines THAT YOU MADE making 200-250 HP. A 250HP non turbo engine cost a serious amount of money to make so your argument is invalid about making more power for cheap.

 

Hell even a 32/36 weber on an EA81 doesn't make that much more power,It just helps the bottom end and gives a little extra fueling up top to reach stupidly fun RPM.However, to make more power with an EA81 a SINGLE PORT FUEL INJECTION is installed which gives it alot more power.

 

If any sort of fuel injection is installed it is really easy and cheap to make much more power,not only that but reliability.Just jump in the car and turn the key and it will start.No messing with the throttle,no messing with a choke,no adjusting the carb when you drive to mountains..

Edited September 23, 2013 by Uberoo

[Quidam]

Hey,

 

Never mind that off the cuff float bowl comment, doesn't belong here. Ivan, I've got a 4 bore Hitachi from a RX4? Anyway, it weighs 50 lbs with the cast Iron base. Need a few parts to complete it.

 

Anyway, I'll read this thread again and see if I can come up with anything constructive.

 

Next carb I buy will be something like this, 2300 carb modified for E85. I'd add a choke and clear sight glass.

[NorthWet]

mabee a big SU or two of them if you like simple can be tuned with oil weight

SUs are "the Devil's Own" to tune properly.  The oil in the piston damper does nothing but alter the acceleration enrichment.  The good news is that SUs don't highlight poor tune with a lot of bad behavior;  Driveability is still good.