Weber Set-Up and Tune Discussion - Page 17 - JeepForum.com
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post #241 of 1074 Old 02-15-2012, 06:27 PM Thread Starter
swatson454
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Originally Posted by Matt1981CJ7 View Post
Hey Shawn,

After keeping up with this thread for a while now, I'm wishing I had given the 38 more consideration when I purchased my 32/36.

What performances differences would I realistically see between the two?

BTW, I hope you're feeling better.

Matt
I think what you'd see is a big increase in off-idle and midrange throttle response and torque.

I know I'm going to piss off a dozen guys with 32/36 carbs and I really don't mean to but I'd size a Weber 32/36 on a fairly stock 1,600 to 1,900 cc Volkswagen.

I ran my first Webers in high school on a built (if you can imagine such a thing but it's true) 1,915 cc Volkswagen with ported heads and an Engle cam. I went with a pair of 40 IDF Webers and the damn thing would take full throttle without a hiccup at 1,000 rpm, even though it loped at idle.

I believe those carbs are good for around 212 cfm per barrel and I had 4 barrels. If you do the math, I should be way over carbureted for the engine size. That's why I always want to slap a guy in the mouth when he talks about some cfm calculator on the internet. Please appreciate my humor when I talk like that.

I guess that story doesn't really apply because it's an I/R application and we're talking about common-plenum carbs. I digress

There was a guy on the forum a couple of years ago with a Solex 34 who carried on and on about how a 38 was a race-only carb and how his Indonesian knock-off 34 was the cat's meow. That dude did more disservice to Weber, forum members and engine tuning in general than you could imagine.

Ok, I'm getting carried away, lol. My opologies.

I suppose the point is that cfm calculators don't tell the whole story and can easily lead guys astray. What's more important than some arbitrary airflow number at max flow is the carb's ability to meter fuel and deliver the appropriate mixture under all conditions.

From what I've seen, the Weber kicks the snot out of other carbs for low-speed metering accuracy. One thing you have to keep in mind is that the idle/progression circuits were designed with a certain amount of air flow in mind. 4200cc on a single 32mm throttle plate with a single idle jet wasn't in the plan, lol. That's actually a testament to how well a Weber works!

A 38 with slightly larger venturi but double the idle/progression circuit area, it is much easier to tune with more accuracy and provides more useable torque. It's most-certainly not "over-carbed" on a 258.

My opologies to those who've had to suffer through this post. Matt, I'm bored stiff, can't leave, on meds, waiting on the Mayo Clinic and apparently terrorizing other people with my opinions is somehow helpful? I don't mean to.

Please bear (bare?) with me. And thank you for asking!


Shawn

Edit: Please also try to forgive all of the mispelled and/or missing words. Work with me here huh. I ain't quite right lately but we're working on it.


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post #242 of 1074 Old 02-15-2012, 10:53 PM
twoscooterz
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Originally Posted by swatson454 View Post
I know I didn't help you much but like I said, it's a judgement call with pros and cons on both sides.

Good Luck!


Shawn

Shawn, on the contrary, you have been very helpful. I have & continue to learn a lot from helpful forum members just like you. I am seriously considering trading my Holly/Offy set-up for a Weber 38 w/ viton needle/seat upgrades on a stock manifold.

Thanks for answering my questions!

'86 CJ7 Laredo, 258, Weber 38, DUI, T5 w/Hurst shifter, 4.56 Dana 30, AMC 20, Detroit TruTrac, Moser axles & Blue Torch truss, Dana 300, stock YJ springs SUA, 33" MTR's, Poison Spyder sliders, NewGen tank cover, Warn 9.5ti w/synthetic rope
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post #243 of 1074 Old 02-16-2012, 04:09 AM
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Can I just say BEST THREAD EVER... I appreciate all the help from reading everyone's detailed info. Thanks!
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post #244 of 1074 Old 02-16-2012, 06:50 AM
Matt1981CJ7
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Shawn,

Thanks, man, reading your posts always reminds me of how much I still need to learn.

I'm gonna keep my eyes open for a used 38 that I can play around with. My 32/36 has treated me very well. It was a snap to set up, it's performed flawlessly, and the mileage has been good, but I can't help wondering if I could get a little more out my ol' 258 with the 38.

Anyway, no need to apologize for the length or content of your post, I really appreciate it.

Take care, my friend.

Matt
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post #245 of 1074 Old 02-16-2012, 07:11 AM Thread Starter
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Thanks guys. I'm on a cellular detox program and my poor head isn't right. What seems like a decent post at the moment looks like a long-winded ramble that lacks direction the next day.

I think I need to be restrained. Must... not... post... on the.... ...forum

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post #246 of 1074 Old 02-16-2012, 07:17 AM
keith460
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Quote:
Originally Posted by swatson454 View Post
I think what you'd see is a big increase in off-idle and midrange throttle response and torque.

A 38 with slightly larger venturi but double the idle/progression circuit area, it is much easier to tune with more accuracy and provides more useable torque. It's most-certainly not "over-carbed" on a 258.

Shawn(
Matt, Shawn,

I too get the feeling that the Weber 32/36 on my engine is inadequate to provide the off-idle and midrange throttle response and torque like I had with the Carter BBD. But it was so long ago that I drove the Jeep with the Carter that I forgot how it was. When purchasing the Weber, I had fuel economy in mind but that has actually gotten worse since my right foot is always into the pedal trying to make up for lost off-idle and midrange throttle response. I had the 32/36 apart more times then I can count, changing jets, air correctors, etc. and the whole time using a LM-2: Digital Air/Fuel Ratio Meter plugged into the old 02 sensor port while driving around and recording the results. I believe I have it dialed in the best it will ever be for a stock engine with 30 over pistons and a non-computer version distributor from a 1980 I6 engine that really woke it up some.

Don't get me wrong, with 32" tires and 4.10 gears, I can be in 4th gear by the time it reaches 35mph and 0-60mph is about 10 or 11 seconds and can always feel the 36mm secondary kicking in but it's a little slow in the response. Sure, I can putts around all day long only on the 32mm primary if I wanted to and get better gas mileage but what fun is that! I might as well stick 33" tires on it and swap axle gears back to 3.31's.

The other reason I bought the 32/36 DGEV Weber was the ability to adapt to the stock air cleaner system that the 38 DGES Weber did not offer. Now after owning and researching, I can easily see that the same adapter can be used on the 38 DGES carburetor to adapt the stock air cleaner assembly without further modifications. What I don't know is if the fresh air intake hole will be large enough for the 38 DGES carb because the adapter closes the hole up some. IMHO, you can't beat the factory air cleaner assembly for controlling cold and warm air entering the engine. Filters are always kept cleaner longer and are readily available just about everywhere too.

So now I'm kind of on the fence in deciding what to do as far as carburetors are concerned. Yes, I will always have a carburetor on my 258 so suggesting FI or TBI is out of the question for those who are quick to respond with a cure-all-answer.... not gonna happen, this is a Weber tune discussion after all.
I wish I had all three carburetors on hand to try. One Weber 32/36 DGEV and a Weber 38 DGES followed by a Carter BBD without the Stepper Motor. Yep, always thought I should have purchased a new Carter pre 1982 model without the Stepper Motor just for ease of installation and setup but shied away from them from previous experience with vacuum leaks around the throttle shafts.

What to do, what to do? $$$$$$....

.
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post #247 of 1074 Old 02-16-2012, 07:51 AM
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Keith,

I, too, feel like the BBD provided better get-up-and-go than the 32/36, when it wasn't leaking or getting clogged up. Throttle shaft leaks was the final straw that caused me to kick my BBD down the road, as well.

At least your 4:10s give you some semblance of decent acceleration. My 2:73s make getting off the line like watching paint dry. That's going to change soon, though. I'm thinking 3:73s might be best with my 4-speed manual and 32"s.

I still have my non-stepper BBD. I did a re-build on it, but the throttle shaft will need a bushing, and it needs a new choke pull-off. You're welcome to have it, if you want to do some performance comparisons.

Matt
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post #248 of 1074 Old 02-21-2012, 01:13 PM
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Shawn I have driven my Jeep several times since doing teh cleanout and rejetting. i think I overshot it - I went from a 45 to a 55 idle jet, as it turns out.

I also went up one size increment on teh mains.

My fuel mileage appears to have been cut radically.

I should split the difference oin the idle jets I guess - is it true they are involved in 80% of driving? If I go back down on idle and leave the mains, i should get a good blend of mileage and performance, seems like.
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post #249 of 1074 Old 02-21-2012, 03:12 PM Thread Starter
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Originally Posted by jeeprider1 View Post
Shawn I have driven my Jeep several times since doing teh cleanout and rejetting. i think I overshot it - I went from a 45 to a 55 idle jet, as it turns out.

I also went up one size increment on teh mains.

My fuel mileage appears to have been cut radically.

I should split the difference oin the idle jets I guess - is it true they are involved in 80% of driving? If I go back down on idle and leave the mains, i should get a good blend of mileage and performance, seems like.
Yeah. A Weber spends the majority of its time on the idle jets. Well, depending on the size of your foot.

IMHO, 50 idle jets will supply more than enough fuel for the progression circuit and you'll probably land somewhere around 1.5 turns out on the mixture screws.

I also haven't seen a need for 150 main jets. If it's performance you're after, your absolute best bet is to swap out the F-50 emulsion tubes for a pair of F-7 tubes. Leave the 170 air corrector jets in there and go back to the 145 main jets. That move alone will make a huge improvement in mid-range torque.


Shawn

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post #250 of 1074 Old 02-21-2012, 06:23 PM
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Hi Shawn-

I dropped the DUI HEI in yesterday. Amazing. So I am at a 258 with a 30 over bore and a weber 38 with 60s in the idle and a 252h Comp Cam. I seem to have a small pause right off idle with a heavy foot. I carry 0 (and I mean 0) vac on the port vac on the Weber base at idle and run the dizzy off manifold. Idle Mix screws at 1.25 out. I have tried 1/16 turn increments and can't shake the pause (albeit a very small pause I am going for "perfection" - what a fun hobby). Thoughts? I do not have a Air/fuel meter, but am I a hair rich? Somehow? No lean burp at idle unless I turn the idle mix screws in to 1 turn. Ideas?

Not complaining about performance I really recommend this setup.......
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post #251 of 1074 Old 02-21-2012, 06:33 PM
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Originally Posted by Matt1981CJ7 View Post
Keith, I still have my non-stepper BBD. I did a re-build on it, but the throttle shaft will need a bushing, and it needs a new choke pull-off. You're welcome to have it, if you want to do some performance comparisons.

Matt
I might take you up on that offer Matt, just to see if there is a significant performance gain or loss.

.
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post #252 of 1074 Old 03-11-2012, 08:58 AM
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Swatson454, do you have a part # for the "$14 upgraded Viton-tipped needle valve." and where can I find it?

I just purchased a Weber 38 for my 4.2L. And yes it's got the "red sticker" vs. "Weber" being cast in the unit! Dang!

Thanks

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post #253 of 1074 Old 03-11-2012, 09:09 AM Thread Starter
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I believe it's p/n 79518.200 or .250, depending on what diameter you want. http://www.carburetion.com/Weber/weberpumpjet.asp second up from the bottom. If you click on the dropdown arrow on the right of that line, you'll see where it says "Viton Needle and Seat" below the two size options.

I don't know if that part will fit in your carb though. Uptillnow or mcmud may know.

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post #254 of 1074 Old 03-11-2012, 04:09 PM
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32-36 help

Hi to all.
I purchased a 32-36 dgv to upgrade my willys L134 engine. I need K553 installations instruction or the original jets data settings to compare with jets supplied with the new carburettor . I am from Italy and nobody knows this kit(not even Weber italian official dealer). I read up on various forum but i had not found data settings about my engine.I also emailed Redline for data but I had not reply. Someone can supply me these information?
thanks to all
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post #255 of 1074 Old 03-11-2012, 09:30 PM
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Quote:
Originally Posted by swatson454 View Post
I believe it's p/n 79518.200 or .250, depending on what diameter you want. http://www.carburetion.com/Weber/weberpumpjet.asp second up from the bottom. If you click on the dropdown arrow on the right of that line, you'll see where it says "Viton Needle and Seat" below the two size options.

I don't know if that part will fit in your carb though. Uptillnow or mcmud may know.
Shawn, two questions for ya:
1) if he's running a 38 on a 4.2, why wouldn't the viton needle work?
2) If you open up the air correctors without changing anything else, what kind of effects will you get? And is there a relationship, i.e. if you open up th air correctors, you should go to a leaner idle jet as well, or just change one thing at a time?

Hope you're feeling better man. I don't know what bit ya, but it sounded bad.
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