Ea81 weber 32/36 or 38/38

[Loyale 2.7 Turbo]

... But I'll plug away. Certainly achieved a lot to date. I'ts revving great and power is way up on the 38/38.

 

You mean that Power and Fuel Economy is Better with the Progressive 32/36

 

than with the Synchronous 38/38 isn't it?

[tweety]

Absolutely. With the 32/36 on WOT it howls with a definite kick in the back. But also with the primary throat only used it is more than adequate power for normal driving. These are the reasons I'm delighted. And the power is progressive throughout the throttle range. Idle is great.

 

I would never recommend the 38/38 for a ea81/ea82. Highly modified engines maybe, with high performance cam and twin port heads etc.

 

I've gone back from 65 on the idle jet to 60. Secondary idle jet 60 to 55. I'm just seeking economy now knowing I have good power and smooth operation. The move to secondary idle leaves me with a mixture screw a little over 2 turns out rather than 1.75 turns with the 65.

 

If there are not good gains in economy I'll return to the 65 idle.

 

Secondary mains from 145 to 155. Being for better top end power/overtaking ability. The little time I use WOT and its ok for the second throat to be rich, I figure its worth that move.

 

Happy 32/36 owner now.

 

My other concept is to make a larger windscreen allowing for air to pass by the rear side roof area. This is causing a parachute effect. Be like owning a Brat with a vertical windscreen. More tinkering. Love it.

Edited August 3, 2015 by tweety

[tweety]

mmm, I don't know if I'm doing the right thing. See the 65 idle jet made the mixture screw out 1.75 turns. About perfect. Then went down to 60 as I'm trying to get the best economy possible.

 

But what if I went to 70? To go the other way it would mean the mixture screw would wind out say 1.5 turns. Would this give better economy even though its a larger jet?

 

Economy runs aren't desired as its near snowing here. I reckon one of those atmospheric gauges would be handy right now

Edited August 5, 2015 by tweety

[Loyale 2.7 Turbo]

... But what if I went to 70? To go the other way it would mean the mixture screw would wind out say 1.5 turns. Would this give better economy even though its a larger jet? ...

 

Sounds as a Good idea to Test, worth try.

[tweety]

Well I'm not totally convinced I'm on the right track.

 

I've read up a lot on weber carbs from a book my mate leant me called WEBER CARBEURETTORS BY Pat Braden published by HP books. It goes through all the basics of how these carb work. Of course it doesn't tell me how it would work with a larger than stock manifold and my SPFI manifold is indeed twice as large as the original ea81 manifold.

 

So what are the benefits of a larger manifold compared to an OEM? I spent the day surfing the www mainly V8 aftermarket manifolds as that's where development has been the most focussed with improvements. (Paraphrasing) See, a larger manifold means it can take more volume doesn't (as I thought) mean more air so that means more fuel i.e. bigger jets. A larger manifold means the engine can run with better efficiency. From my reading I've realised that one should use the recommended jets and move up one or maybe two sizes at the most to achieve the best performance. Any further in jet sizes and you run the risk of using more fuel for no gain.

 

Furthermore, my trike at 660 kgms, auto trans, 9.5:1 CR, torque cam etc is like most vehicles- unique. I shouldn't take other vehicles as a base line.

 

Read this from GD

 

"I think with the Delta cam you need to go lower on your idle jet. You have the torque cam I take it? You are getting a lot more draw from the cylinders at idle than before, and you're sucking huge quantities of fuel because of the massive vacuum at idle. The engine breathes better now, and all it's getting is a ton of gas from the big idle jet."

 

GD http://www.ultimatesubaru.org/forum/topic/9440-who-has-weber-bible-need-to-know-the-actual-jetting-im-supposed-to-running/

 

using the Gudson colortune will be a bonus. But this device wont tell me to go higher or lower on jetting, just the right mixture.

 

Redline kits jet their engines at

 

Primary- idle 50

main 140

air 170

 

Secondary idle 55

main 140

air 160

 

One bit of instruction was - from Article "Retrofitting the weber DGAV 32/36 to Subaru manifold" It says- Tuning of the weber can be done with a flat blade screwdriver and your foot. To tune the primary circuit set you A/F mix and then set your speed screw so that its running at about 2000 rpm. Slowly turn the mixture screw out, if the engine runs faster the mixture is weak and you should go up a size in the idle jet. Slowly turn the mixture screw in. If it runs faster the mix is rich. Go down a size in idle jet. If you change a jet, you need to redo the A/F mix setting BEFORE repeating the procedure.

Once the idle circuit is set, take your Sube out on the road. Idle along the road with clutch fully engaged. Tromp the pedal and see if it will accept WOT at idle. This gives you an idea on the main jet size. If it stalls then there is a lean condition, if it makes a deep tone it is rich. This is a rough guide...."

Edited August 7, 2015 by tweety

[Loyale 2.7 Turbo]

... Once the idle circuit is set, take your Sube out on the road. Idle along the road with clutch fully engaged. Tromp the pedal and see if it will accept WOT at idle. This gives you an idea on the main jet size. If it stalls then there is a lean condition, if it makes a deep tone it is rich. This is a rough guide ...

 

Hard to tell if the Carburetor makes a Deep Tone, if you have a short and noisy exhaust pretty close to your Head, like in your Trike...

 

Also, my 32/36 Progressive Weber, makes a Deep tone under hard acceleration, but that is somehow "Natural" for those webers; it made a deep tone with the 140 / 140 main fuel Jets when the carburetor came new from factory, tuned to be installed on a EA82 Subaru Engine, and it does absolutely the Same deep tone with the 140 / 162 main fuel jets that it has now.

 

All these books, guides, writings, inspired my Signature here... 

 

Kind Regards.

[tweety]

Yeh, thought that also. My main focus tomorrow is the primary side. And I'll get that right and go for a 15 mile ride on primary only and check the bosch plugs color. Should be some indication.

 

Looks like I'm soon to become an artist lol

[tweety]

Final day for tuning.

 

Thought I'd check the dizzy first. Found that the vacuum advance was seized at the diaphragm. Had a spare and it worked fine. So I haven't had vacuum advance at all for quite some time. In fact it was really apparent when I put a timing light on the crank pulley (my engine doesn't have a flywheel with timing marks as it has an adapter plate) and when I took off the vac tube form the carb the timing moved about 3 degrees. So left it off and timed it to my regular 13 degrees and on with the tube. Definitely noticeable difference when revving.

 

I decide to go back to redline jets and start again. Being Primary main 140 air 170 idle 50 Sec main 140 air 160 idle 55

 

Then the test as above where by you alter your mixture screw until it is set. I used my colortune for this operation. Then raised the idle to 2000rpm. Then screwed the mixture screw out and revs rose a lot. So according to the method you raise the idle screw one size in this case 55 then repeat the procedure. Nope, still no good so installed a 60 size idle jet. Perfect....almost. There was the slightest rise in revs but so little I'm happy with that. Mixture screw is 1.5 turns out from home Revved the engine 3000-4000 rpm. Not really happy with that. Seems it was light on fuel flow to me. Primary main is 140. Replaced this with a 145. Air is 170 replaced this with the 180. Took it for a run. Wow, am happy with that. Bearing in mind I have vac advance now also.

 

Secondary. With the 140 main I wasn't happy with the WOT. Bit light on with power at the top end noticeable up a long hill. Replaced it with a 150..air went from 165 to 180 and left the idle at 55. Was happy with that.

 

The final thing I wanted to do was adjust the timing until it pinged then back it off 2 degrees. Well I advanced it more and more and each time went uphill to listen for pinging that never came. Then it began to run a bit course. Back to the setting at 13 degrees. It starts easy there, runs hard and I'm happy.

 

So jetting wasn't far off what I had yesterday. I rode home about 12 miles and then took out one platinum spark plug. The white ceramic piece was white and brown.

 

Final jet settings are- mains 145/150, airs 180/180, idles 60/55 The colortune helped a lot as it took away the guesswork of the mixture. The more precise the mixture the more accurate that test is when you up the idle then open the mixture screw. I'm happy with that test.

 

On a private road the trike exceeded 140kph 85mph with more there . Am real happy. With the 38/38 even after dyno tuned there is no way it would get near that speed, nor the roar of the carb at WOT and the kick in the back the 32/36 gives. Lessen learned. 38/38 carbs might be good for highly modified stock engines. As the ea81 and e82 cant be developed that much there seems no positive purpose for the 38/38 carb on these engines.

 

Thankyou to all.

[LucasP]

I've been reading through this whole thing with a ton of interest. I'm always having my own webber experiments on my ea82. Loyal has helped me a bunch with all his info on the subject.

 

I can't help but think that your intake manifold is really a mute point in the whole thing. The issues with the ea engines is that the heads don't flow. All the manifold work in the world isn't going to help much if you can't get that air in and out efficiently. Most of my experience is with aircraft carbs tho.

[tweety]

I see your point Lucas but there is one factor that sways me the other way- that there is a SPFI system on ea82's that has this manifold and with the same restrictive heads. If it was too big for the engine then Subaru would have stuck with the ea81 manifold. That's my line of logic anyway. Don't you think?

 

4 years ago when I first got this ea81 engine I stuck a weber on it (was sold without a carbie) so I'm aware of what an ea81 is like with a 32/36). Yes, this engine now has higher CR and a torque cam but whatever the reason this engine is now sorted and it really takes off.

 

Was fitting the SPFI manifold worth the effort? likely not. The 6 mounting holes need to be reamed out as the heads are closer together, the crankcase needs to be ground down 2mm so the SPFI manifold has clearance and the angled mount I had made up for the weber was custom made and cost $$$. Better for the average owner to stick with the ea81 manifold. But if you have a SPFI manifold I'd go with it. I'd love to get a automotive engineer to PROVE the advantage though.

 

Thanks for your comment.

[jono]

i read that you did all this last bit of happy tuning yourself - what this forum stuff is all about - and shared the ins and outs as you went.

 

i seem to recall you 'knew better' [wrong choice of words I know] than all those others that said don't go 38/38 [not sure any of them had done same proposal, just nay sayed - could get shot down from this comment too !} , too much, and then you had those with 38/38 on Datto 1200 reckoned it was fine.

 

Which way did you go ? Same track I would have is what you did .

 

Important thing is you tried, been there done that , and continued to share the good with the bad findings.

 

Some would skulk off the forum a while, sneak back when interest has waned and not share failure - seen it a few times

 

i once did a 465 4 barrel vac secondary holley onto an enlarged manifold, on an engine that basically got a single barrel, that got an upgrade to two barrel. I knew no better, someone put the idea in my head, suggested a 390 would be better choice, there was no 'net in 86 thank goodness

 

and I scored the 465 for free

 

I later found I had my doubters thinking i was using a bucket to pour petrol into its 250 ci. The 230 primaries got nice and lean, and secondaries a lil bit richer, read the Holley books of the day, made more discoveries than ever disclosed in print about vac diaphragm springs. Got great power when asked of it, great economy when asked of it .... 30 miles per 4.546 litres at 70 mph touring speed, watching vacuum gauge ..

hang on ... I struggle to get that from my 4 pot rice burners ..NA or turbo !!  .... WTF am I doing here ??? SLAP , should migrate to a ford forum !!

 

Near 30 years later, still got car and engine, still got Holley hoarded somewhere too - should put it all back together to see how it goes on modern fuels !! One day .

 

Tony, top marks for sharing , but, now, just because a manifold holds more volume than another, I don't see it needs bigger jets to give it more fuel, just has more mixed air fuel at the ready for call on the valves, may just take more time for volume to fill. Get me thinking on this - ?

 

Also note your 13 degrees, any more and got a coarseness. I have got that coarseness in sound and power only @ 16 DBTDC @ 800rpm idle, vac plugged for tuning, my economy has improved ..the 540km per 65 litres dropped to 500 or so @ 6 DBTDC, and now stretched the 65 litres to 600 km with some special low speed 4WD bush driving, snow ploughing etc !

Edited August 8, 2015 by jono

[tweety]

Thanks Jono,

 

The only comparison between stock manifolds and large manifolds is the V8 world, where aftermarket manifolds are plentiful and wouldn't be for sale for 4 or more decades without some improvement in performance. It was there that I learned that bigger in manifold size often means better efficiency. ???? I'd love some facts on this.

[LucasP]

I see your point Lucas but there is one factor that sways me the other way- that there is a SPFI system on ea82's that has this manifold and with the same restrictive heads. If it was too big for the engine then Subaru would have stuck with the ea81 manifold. That's my line of logic anyway. Don't you think?4 years ago when I first got this ea81 engine I stuck a weber on it (was sold without a carbie) so I'm aware of what an ea81 is like with a 32/36). Yes, this engine now has higher CR and a torque cam but whatever the reason this engine is now sorted and it really takes off.Was fitting the SPFI manifold worth the effort? likely not. The 6 mounting holes need to be reamed out as the heads are closer together, the crankcase needs to be ground down 2mm so the SPFI manifold has clearance and the angled mount I had made up for the weber was custom made and cost $$$. Better for the average owner to stick with the ea81 manifold. But if you have a SPFI manifold I'd go with it. I'd love to get a automotive engineer to PROVE the advantage though.Thanks for your comment.

The spfi manifold makes more power in the fuel injected engines because of the superior fuel delivery not the intake design. At least that's what I suspect. For example the 360 in my jeep... I went from throttle body injection to multi point. Much better power and mileage because of the better delivery system not the intake. I think guys probably do it because in theory it would make better power. I'm sure it does flow much better, but it's probably so negligible with the stock heads.

 

And granted that's just my thoughts. I love you trike and if I had the time I would try the intake on my car just to see. Tinkering is fun. It's not an old Subaru if you aren't working on it. Lol.

[jono]

Phew, got a like on my last post, so no one took offence

 

I guess Tweety now has the option to have a standard EA81 or EA82 carb inlet manifold installed to see if any different - but maybe after a rest period

 

I still have a weber 32/36 manual choke - [another freebie from same Holley contributor 1/4 a century later !] I am sort of tempted to fit up in the name of tinkering to see how it goes......it was jetted for a lighter 1800cc machine - MGB II which ran so sweet .

 

If only I knew where to find said jets !!

 

I think the larger volume of the spfi is leaning towards the old theory of inlet volume beteen throttle plate and valves is best up to same capacity as all cylinders in the name of power and efficiency. Might be difficult to keep carb fused air/fuel mix in suspension in larger volumes such as the EA82 spider manifold. My intention is to try this one day on my EA82M, going against the smaller volumes being better for propane systems The spfi might be a good compromise between larger mpfi swept volume ? is that the word ? and smaller carby inlet manifold ??.

 

I can't see Tweety going down the spfi conversion road anytime again. Sounds like you have Tweets sorted just right now - and without a dyno shop this time . Wondering if the vac can was stuck in dyno sessions ?

Edited August 8, 2015 by jono

[tweety]

This trike has taken all this time to get it to a trike of fun. I'm nearly 60yo now and I look back on my struggles with other troublesome cars like my 2 lotus powered Ford Escort, Datsun 2000 sports and numerous Ford Zephyrs and think to myself....time to enjoy this one.

 

Hence I wont be going down the road to trying out a ea81 manifold, changing jets again, purchasing a redline adapter, mofifying radiator hoses etc all to just find out if the SPFI manifold is better performing. I think most here agree that any real performance benefit in terms of economy and acceleration would be miniscule.

 

The transformation of this trike has been dramatic. I tried towing a mini caravan (trailer) at 600kgms, twice the legal weight here in Oz and needed more power hence the supercharger. Tried SPFI but couldn't justify the never ending costs to replace 30 yo sensors with what for me was a little more complex for my comfort zone. Now I'm happy. Happiness comes in many forms. For me to have a ea81 fully rebuilt in every way with the right cam (thanks Jono for that) even new oil pump and rebuilt dizzy everything is tight and new, no oil leaks (yet), oil usage or irregular idle etc Is happiness.

 

Tweety the trike isn't finished yet. A new larger custom built windscreen from polycarbonate is on the list. Custom fairing around the front radiator as well. Tires are a problem. I really want larger tires to allow me lower revs at 60-70mph. but I need whitewalls. In Oz no tire can be used without Australian standards markings. Very over regulated here yet we can expose boobs whereas in USA Janet Jackson stopped the country with her - "accident" lol.

 

When I started the transition from VW 1916cc to ea81 I was questioned heavily by some that queried the swap (fair enough). EJ was their cry. But with unusual vehicles come unusual answers to a problem. With Tweety it was a case of a weight issue. The frame is unique in Oz with a full alloy monocogue chassis not steel tube. An EJ like all other engines out there weighing more than the VW engine (light weight air cooled) would weigh more. Add to that the roof weighing at 45 kgms and you have an issue. The ea was the answer as it was very compact (more room for exhaust of my design), weighed less than VW and a little more with the radiator and coolant and most importantly for a regional resident- easy to maintain and work on myself. Gee maintenance- it has a module in the dizzy, all I need to do annually is valve clearances, spark plug change, lead inspections and oil/filter fuel filter change biannually. No computers. This engine will largely go untouched for the rest of my days- unless, twin port heads become readily available and reasonably priced...then I'll save my pennies.

 

I've learned so much and my knowledge now will assist others new to the ea engine as I'm not going anywhere. The membership here is quite unique.

 

 

 

 

 

[tweety]

Well this is the last step of the 38/38 to 32/36 swap.

 

Recap- stubbornly tried a new 38/38 weber on my newly fully reconditioned ea81 with SPFI manifold (15/55 cam and 9.5:1 CR). 38/38 was dynode twice and in between dynoes the jets were ordered. The engine pulled a lousy 52hp. Compare that to over 100hp when it was supercharged...but that's another story.

 

The 32/36 was tuned by me using - 1/ jet sizes based on other ea81 owners/redline etc 2/ using Gunson colortune device 3/ test riding and so on.

 

I'm please to report that I achieved (these are based on Australian gallons) 31mpg over one tank full of gas. or 9L/100kms. Compared to the 38/38 at 19-23mpg.

Yes I was light on the throttle with a few bursts here and there and cruising freeways at 105kph.

 

So I'm happy. The next step will be to replace the rear tires from 295/50R15 to 275/60R15 in the future giving it longer legs and 200 rpm less at 60mph.

 

I'm really happy with its performance. With the engine new it has heaps of power down low with that torque cam.

 

Cheers.

[Loyale 2.7 Turbo]

Regarding the Tires...

 

I see that you're using pretty Taller ones which incise directly on the Acceleration,

 

especially from Lower speeds; why don't you try smaller diameter ones?

 

Kind Regards.

[tweety]

Hi JesZek,

 

Smaller diameter tires will mean higher revs. I already have 3200 revs at 60 mph.  What I want it larger diameter tires. Ive figgered it all out now. 275/60R15 will give me 5% less revs.

 

The better news today is the economy. Cruising at 110kph - 70mph (and maintaining that on hills) with some city freeway cruising I did 418kms for 39 litres of gas. Or 268 miles on 9 gallons Aus. meaning 30mpg aus. equals 25mpg US. I used heavy throttle 5 times (opening the second throat) which is likely normal because first throat gives adequate power.

 

With a 48 litre tank I could achieve up to 500 kms a tank.  This is really pleasing. In fact I couldn't believe the fuel gauge was taking so long to go down.

 

Considering the max tank distance with the supercharger was 210 kms and the 38/38 about 320-360 kms this is a huge leap forward for me. Add tires that are 5% larger in circumference might get even better results.

 

Steptoe,   I have many jets you are welcome to try when the time comes. Ebay USA has many sellers with boxes of jets. Send me a message when the time comes. I wont have much need for them now its all tuned up. Once you have it tuned you can place your old jets back in the box and return it to me. Good offer there.