How much to step down on the mains?

mxracer · Last edited by mxracer on Thu Jan 12, 2012 4:31 pm; edited 1 time in total

I have a 1904 that I"m now dialing in. I believe I have things figured out with the exception of the mains.

They are Dell 40s and right now they have:
30mm vents
52 idles
180 airs
120 mains
9164.2 e-tubes

My AFR meter is reading pretty well with the exception of WOT. It dips down in the mid 11s and stays there at WOT.

Any suggestions on how far to drop the mains to get to the high 12s - low 13s at WOT?

Here's some of the engine info if needed...

1904 cc
Engle W110 with 1.25:1 rockers
stock type 3 heads P&P and HD single springs
Tri-Mil over the top exhaust
9.1:1 CR

Thanks in advance.

baked beetle · Posted: Thu Jan 12, 2012 4:29 pm Post subject:

what are your emulsion tubes?
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66' His
57' Theirs
63' Hers
62' Drag Bug - Theirs 13.1 @ 101 mph (GONE)

mxracer · Posted: Thu Jan 12, 2012 4:30 pm Post subject:

Oops..sorry...corrected above

baked beetle · Posted: Thu Jan 12, 2012 4:49 pm Post subject:

I would say one step would get you mid 12's which is good for WOT. but yea if you want to get the next step down 110, might be closer to 14.

this is a guessing game for anyone, if your the one with the wideband Smile

do you have extra jets or are you ordering
_________________
These days people like me are hard to find- we don't give a damn what you think, about what we think. - JR
____________________
66' His
57' Theirs
63' Hers
62' Drag Bug - Theirs 13.1 @ 101 mph (GONE)

mxracer · Posted: Thu Jan 12, 2012 4:59 pm Post subject:

I'll be ordering again. I wanted to get some input on what to order before I did so I don't have more jets lying around. Smile

Bill271 · Posted: Thu Jan 12, 2012 6:00 pm Post subject:

Try a 200 air

MURZI · Posted: Thu Jan 12, 2012 6:24 pm Post subject:

What is AFR at a steady 3500 ?
_________________
62 vert
2276
Tim’s welded heads
45 Dells
A1 sidewinder
Fk44 cam

mxracer · Posted: Thu Jan 12, 2012 6:27 pm Post subject:

Right now it's 13.1-13.2 hoping the main drop will also move that a but and get me to the mid-high 13s

It's in a Type 3, so I'm not convinced I'm going to get the 16s that seems to be the goal with a Type 1. I'm pushing a little more weight.

MURZI · Posted: Thu Jan 12, 2012 6:40 pm Post subject:

Try to reduce pump shot first. Also you may try a 6mm float level.
_________________
62 vert
2276
Tim’s welded heads
45 Dells
A1 sidewinder
Fk44 cam

Slow 1200 · Samba Member Joined: July 02, 2004 Posts: 2105

in a type 3 you are probably running low profile air cleaners right? those probably are kind of restrictive as far as supplying air at WOT

mxracer · Posted: Fri Jan 13, 2012 6:20 am Post subject:

Pumps are backed all the way out at this point for tuning.

Changing float level will be last resort. In order to do that without 2 hours of "pain" I have to pull the engine. Smile

Yes, they do have the short stacks and air cleaners on them. With a much bigger air (about a 2.50) I can get the main to the high 12s at WOT. The transition sucks at that point though. The restriction plays a part I'm sure. I am going to try a set of 2.00 airs today as suggested above too and see where that gets me.

I ordered a set of 115 mains to see how they work. In the end I'm testing and learning to it's all good.

Appreciate the suggestions and keep them coming.

MURZI · Posted: Fri Jan 13, 2012 7:58 am Post subject:

You can progressively drill those airs bigger....much cheaper.
_________________
62 vert
2276
Tim’s welded heads
45 Dells
A1 sidewinder
Fk44 cam

mxracer · Posted: Fri Jan 13, 2012 8:03 am Post subject:

Yep, with you. The one set I have I've drilled up to 2.5mm. They are currently soldered back and at 1.85. Those are the ones I'll drill to a 200 and give it a shot.

Thanks

MURZI · Posted: Fri Jan 13, 2012 8:29 am Post subject:

A slight bump in ignition timing, say two degrees, may help "clean up" that AFR slightly. Try it.......
_________________
62 vert
2276
Tim’s welded heads
45 Dells
A1 sidewinder
Fk44 cam

mxracer · Posted: Fri Jan 13, 2012 12:39 pm Post subject:

W1K1 · Posted: Fri Jan 13, 2012 12:45 pm Post subject:

Have you tried running on just the idles with the main jet stacks out to get the idles figured out?
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1973 super
1965 squareback 1500E
1971 bay window westy- subi swap

mxracer · Posted: Fri Jan 13, 2012 12:55 pm Post subject:

Yes, that's where I started a while back. The 50's dialed in nice without the main stack, but like I said I never did drop below that.

Have you gotten 16-17 at cruise out of your type 3?

MURZI · Posted: Fri Jan 13, 2012 12:57 pm Post subject:

Just curious, what is your elevation?
_________________
62 vert
2276
Tim’s welded heads
45 Dells
A1 sidewinder
Fk44 cam

mxracer · Posted: Fri Jan 13, 2012 12:59 pm Post subject:

856 ft according to google.

I'm guessing (cause this is my first real round with duals in a type 3) that between the stock size valves, 30mm vents, short stacks, short manifolds, and short air cleaners it's a little "out of the norm". Question

MURZI · Posted: Fri Jan 13, 2012 1:03 pm Post subject:

Just wondering because I went through HELL try to tune some 36 dells a few weeks back and wound up waaaaaay fatter than your jetting. I am at sea level. Crazy......

Your jetting seems spot on to what it should be...mine wasn't.

http://www.thesamba.com/vw/forum/viewtopic.php?t=489666&highlight=dell
_________________
62 vert
2276
Tim’s welded heads
45 Dells
A1 sidewinder
Fk44 cam


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