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Who has Weber Bible. need to know the actual jetting i'm supposed to running.


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well my carb has never been jetted right. it was used and not off a subaru. so i get a lot of dieseling. and i also want the best of performance out of it. so i need to know the jetting that the bible states for the ea81 engines. thank you.

 

need to rejet as soon as i get the cash. probably next month after i pay everything off. along with a hotter coil. and new fuel pump and regulator.

 

searched but found too many answers that were way differant.

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I think that subaru engines are just prone to dieseling at shutdown. Mine was reduced by installing cooler plugs, but it still happens on occasion. That's why the hitachi carbs have an anti-diesel solenoid that cuts off fuel when the ignition is turned off. I don't think jetting should matter for this, but I'm no carburetion expert either.

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Yeah, I gots the same problem. Runs rich. When it rains, say bye bye to power. :banghead: THAT don't make sense to me: raining = denser air which I would think would lean out the mixture. Getting it closer to a 50/50 mix. :cornfuzz:

I decreaced my dieseling by switching to Chevron gas. Still using 87, but it doesn't diesel half as much as it did on the higher gades from the other stations around here.

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In Nov BYB555 on the aussie site posted he had been running 125's as p and secondary mains, w/ 140 and 160 as air correctors in the top prior to doing mods to his powerplant. Post upgrades he siad he had been running 140's in the bowl and 165+180 as air correctors.

The carb Cameron sent me was off a crtina, I dont think he changed jet sizes although I guess its possible he may have let them trade places on reassembly- it had 132+140 as mains and 175 and 135 as air correctors.

I still want to pull the top off a redline carb as sold to soob guys and see what they put in there. In weber books there seem to be good listings of stock weber set ups where applicable, but these listings don't cover aftermarket mod set ups (that would be a big list I'd bet) They do provide some examples of 1.8L motor applications though...

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  • 7 months later...
In Nov BYB555 on the aussie site posted he had been running 125's as p and secondary mains, w/ 140 and 160 as air correctors in the top prior to doing mods to his powerplant. Post upgrades he siad he had been running 140's in the bowl and 165+180 as air correctors.

The carb Cameron sent me was off a crtina, I dont think he changed jet sizes although I guess its possible he may have let them trade places on reassembly- it had 132+140 as mains and 175 and 135 as air correctors.

I still want to pull the top off a redline carb as sold to soob guys and see what they put in there. In weber books there seem to be good listings of stock weber set ups where applicable, but these listings don't cover aftermarket mod set ups (that would be a big list I'd bet) They do provide some examples of 1.8L motor applications though...

Caleb, did you ever find out the info on the jetting? I'm having an emissions issue with the new engine (fails bigtime HCs at idle) and wondering if reducing idle jet and increasing idle air would help).

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I have a weber off a 1.9 litre Opel Manta, and it had 155's for both primaries, and like 165, 175 for the air correction jets.

 

it's now currently running 140 primaries, because I was trying to dignose a problem, but I will be going back to the 155s.

 

this is with a totally de-emmissioned vehicle with custom exhaust work, and a slightly worked intake.

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Stock from Redline for the Subaru is:

 

Primary Main: 140

Secondary Main: 140

Primary Air: 170

Secondary Air: 160

Primary Idle: 50

Secondary Idle: 55

 

This gave me 32 MPG freeway on my 2WD wagon, same jetting on the same engine gives me about 18 MPG with it lifted and 4WD. I think for a stock engine, this jetting is fine, maybe a bit large. But it still gets better mileage than a similarly eqquiped Hitachi (non-feedback). I drove to Medford with a friend in a lifted hatch - he had less weight, and smaller tires (27's - mine are 28's), and he got about 17 MPG with the Hitachi.

 

GD

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Stock from Redline for the Subaru is:

 

Primary Main: 140

Secondary Main: 140

Primary Air: 170

Secondary Air: 160

Primary Idle: 50

Secondary Idle: 55

 

This gave me 32 MPG freeway on my 2WD wagon, same jetting on the same engine gives me about 18 MPG with it lifted and 4WD. I think for a stock engine, this jetting is fine, maybe a bit large. But it still gets better mileage than a similarly eqquiped Hitachi (non-feedback). I drove to Medford with a friend in a lifted hatch - he had less weight, and smaller tires (27's - mine are 28's), and he got about 17 MPG with the Hitachi.

 

GD

My only problem is to get it to pass emissions. HCs at idle are around 600ppm: just passes at cruise. Gas mileage is better than I've ever gotten with the Hitachi. Coming back from WCSS6 with a fully loaded Brat (three sets of wheels and tires and a bunch of tools and parts) and towing a small utility trailer fully loaded with more stuff, I got 27.7 mpg. Nothing to complain about there.

 

GD: Judging from the jet sizes, I suspect I should decrease the idle jet opening one or two sizes and increase the air jet accordingly. Does this make sense?

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Yeah - that sure sounds like a winning plan. If your problem is only at idle, then it sounds like the idle jet wants changed...... change the o-ring on the jet holder for the idle jet as well just for good measure. I would get a jet "kit" with several sizes in it, so you can play around with all of them.

 

27.7 is not bad at all for a 3.9 car. I routinely get 28 or maybe a bit more in my Brat with the Hitachi, and everything I've read on the Weber's sugests they should get slightly better mileage than a Hitachi, so you should probably check all your jets just to be sure. With the delta cam like you have, the engine may want for different jets.

 

Also note that best performance doesn't also mean best mileage. The difficulty in tuning a carb is that the engine doesn't draw in the air and fuel at the same rate over the entire RPM band. The carb *could* be tuned to give maximum performance at a specific RPM reading, but that may shoot you mileage in the foot at some other reading. So a balance must be struck.

 

GD

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This is Big Jim, the Weber Guru. The first post from Tim, tells a lot of info. We have all the jets available to tune the carb. But I think a 140 primary and a 135 or 140 secondary main and about 165 -170 airs and you have to play with the idle to get the best for either passing emmissions or to run good, 55-60-65 is most popular

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This is Big Jim, the Weber Guru. The first post from Tim, tells a lot of info. We have all the jets available to tune the carb. But I think a 140 primary and a 135 or 140 secondary main and about 165 -170 airs and you have to play with the idle to get the best for either passing emmissions or to run good, 55-60-65 is most popular

I checked what is in mine and I found 45 and 50 idle jets for the primary and secondary; 170 and 160 for the primary and secondary air correctors. I'm still looking for where to find the main jets.

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For the mains, you'll have to pop the top off the carb - remove the air filter, and you'll see 6 flat head bolts. Remove those, remove the small (very small) clip on the choke lever, and the top will come off. Down inside the float bowl, you'll see two little brass jets - should both be 140.

 

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

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For the mains, you'll have to pop the top off the carb - remove the air filter, and you'll see 6 flat head bolts. Remove those, remove the small (very small) clip on the choke lever, and the top will come off. Down inside the float bowl, you'll see two little brass jets - should both be 140.

 

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

Rick, I think you're correct in your assesment. A smaller primary idle jet. I spoke to one of the guys at the Lynnwood Bow-Wow shop this evening and he gave me a simplified description of what might be happening. Primarily (no pun intended) the weber does almost everything off the primary idle jet and mixture adjustment up to about 3000 rpm. The secondary idle jet is just there to provide a smooth transition for the secondary barrel when it starts to open up at about 3500 rpm. Air corrector jets do not affect things much as long as enough air is getting into the mixture; the main jets only affect things in the upper rpm range. So that leaves me with the choice of just dropping the primary idle jet one or two sizes from the 45 that's in there now. Now if I only had a sniffer to tell whether it made a difference.

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Update. Seems Bow-wow had the right idea, but the primary idle jet is an air bleeder jet. To lean out the mixture I need to go up in size (50, 55, 60, etc.) until I get the right mixture; this is from the tech guy at carbs unlimited. I still wish I had a way to tell if the emissions was better or worse.

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