Weber 38 DGES redline kit 662-38 Jets and tuning

[poopypants720]

I just picked up a new redline Weber conversion kit (K662-38) for my '81 4x4 KC.

 

After much searching and phone calls to all the leading distributors, even redline themselves, I realized there was no provided info on what jets come in this "pre tuned" kit for our application.

 

So this will be an overview of what this kit offers stock and the tuning for my own personal application.

 

Hopefully it helps someone else looking for similar info.

[poopypants720]

Stock baseline jetting for the Weber 38 DGES/DGAS (as found here http://www.racetep.com/webercarbjet.html)

 

Main Jet

145

 

Em Tube

F50

 

Air Corr Jet

185

 

Idle Jet

45

 

 

"Pretuned" jetting for the Weber 38 DGES/DGAS as provided in the K662-38 kit for the Z22 and L series motors

 

Main Jet

145

 

Em Tube

F50

 

Air Corr Jet

170

 

Idle Jet

50

 

 

 

So they have made this application to have a richer idle circuit and richer top end with the two changes in jets over baseline.

[poopypants720]

My personal application and tuning notes.

 

This kit is going to be used for my "fun" carb on my truck as it's basically a weekend warrior and not driven much. Mileage is not a huge concern and I have another smog legal weber that tunes great to pass smog and even tunes well for some decent pep and driveability when needed.

 

Current engine modifications:

Stock rebuilt Z22 motor*.

Doug Thorley long tube headers.

Custom routed 2.25"exhaust piping run through Flowmaster 40 series muffler.

5sp maximal trans.

Stock gearing in front and rear diff and transfer case.

31x10.5r15 Toyo Open Country MT

 

*would like to get a RV profiled cam, but don't know if I'd be able to pass smog after that modification

 

Location:

Mojave Desert

 

Altitude:

2,500' (most driving will be done there or higher)

 

 

Notes:

 

2/10/16 (pre install)

Tuning will be done according to included step by step instructions for lean best idle that are well known to all who own or have tuned a weber carb before. I assume that it will also run best on 91 octane with 10°-15° advance, much like my other weber.

 

I also suspect that I will need to lean the jets out a bit to achieve the best overall effect for the elevation range I plan on driving it most (2,500'-5,500'), considering these kits typically come pretuned for sea level.

 

Reading these two articles for overall efficient weber tuning http://www.racetep.com/webjettune.html and tuning for high elevation applications http://www.racetep.com/weberaltitude.html and overall reading across various message boards leads me to believe I'll definitely be dropping my idle jet one size and likely increasing my air correction jet 2-3 sizes... I may be able to leave my mains alone as it should lean it a little at the top with the air correction but stay rich for a smooth transition from the idle circuit to the main circuit...

 

Of course I'll be tuning as is first and determining necessary corrections for idle based on my screw turns and then once that's tuned my mains will change based off mid range flat spots/transitions and spark plug checks... But I'll probably be purchasing the high altitude jet kit regardless and will be taking it on a wheeling trip at 4,600' right after everything is up and running to test it out.

 

More to come once installed.

 

3/4/16

Got the 38DGES installed finally. Everything runs great as jetted from the factory so far! Almost right in line with starting tuning specs!

 

Suggested start:

 

Idle speed screw: 1/2 turn in

Idle mixture screws: 1 turn out

 

Final settings:

 

Idle speed screw: 1/4 turn in

Idle mixture screws: 1, 1/4 turn out

 

Never broke loose my tires on asphalt before this(31") but now have no problem doing so... Also took it on a quick of road excursion and it performed great, no bog in power when needed, no dying on steep rocky/bumpy climbs, no fuel leakage from bowl.

 

Area I was at was:

 

962.413 m or 3157.524 feet

Location :34.92365621545044,-118.25007677078247

 

So being on the lower end of the elevations I'll likely be seeing, I'm still happy that I'm so close to standard adjustments. Hopefully, if any offroad tuning is needed, I'll find myself within my adjustment range still and won't wind up needing to lean out the carb with smaller jets. Plan on seeing trails around 3,600' and another trip around 5,000' so hopefully it does well with both and I'll report back with any changes.

[Charlie69]

Good information.

 

When I ordered my current Weber DGEV 32/36 for my 1986 Nissan 720 King Cab 2WD Z24 5 speed 3.70 rear end ratio, from Peirce Manifolds 5 years ago.  I order it with factory jetting.  This was because I would be returning to Phoenix AZ even though I lived at the time in Battle Mountain NV.

 

Phoenix elevation is 1,086′, Battle Mountain elevation is 4,511′. 

 

I did not bother with re-jetting for the higher altitude.  The truck performed OK.  Would have had better mileage and power if I re-jetted.

 

I should re-jet but honestly I am getting 28 mpg in the city and 30 mpg on the hi-way if I keep my foot out of it.  But I drive it like I stole it.

 

I have been running Weber DGV series carburetors for over 40 years.  I enjoy the power gain from the stock Nissan/Datsun Hitachis.  These are a simple well designed carburetor and will last for years.

 

If you search hard enough you can find information on modifications you can do to your Weber Carbs for better performance.  Some of the mods require drilling precise holes to re route some of the fuel.  These mods are not for the shade tree mechanic to do.  I will not put links here for the mods because I do not want to be held responsible for some one ruining their Weber!

 

If you are inclined to do some of these mods or study them search them out.

[poopypants720]

I like to have know how, wether it's applied or not.

 

I was reading a thread on specific jetting and tunes guys were doing to their first and second gen accords using webers for hours the other day... before my scatter brain took back over and had me opening another tab, LoL... I always seem to have 10-20 tabs open on any one given topic and I constantly jump back and forth between them. Probably not the most efficient way to get info.

[poopypants720]

Updated original post