engine and drivetrain Best Dual Sidedraft Carb Setup?

[Kidasters]

OK - after a few weeks of parts buying, I feel pretty confident to discuss a few of the kits out there, and give my opinion to the group as to what I think the best setup to get is.  I base "best" on ease of assembly, and not having to make any modifications to parts (ie - grind a boss off a carb, etc...). 

 

Ireland Engineering Sidedraft kit

 

Includes:

IE intake manifold

Redline generic dual carb linkage kit

blue silicon hoses 

stainless steel water bypass tube

 

PROS: 

You can get this all from IE on their website.  One stop shopping.

At extra cost - IE includes special clearance nuts to make up the manifold to the intake.  Handy, I guess.

Each throttle arm is independent, so you can fine tune adjustments between carbs.

I think blue silicon hoses look cool.  But that's me.

 

CONS:

The IE intake "needs some work".  A lot of work.  Not only is the inside of the casting very rough, but there have been problems with the alignment of the holes with the studs - meaning, if you thread the studs onto the manifold, the carbs won't just "slide" right on.  At that point, I'd had enough - and have abandoned using this manifold.  $75 bucks worth of machine work gone, plus the cost of the manifold.  Oh well.

 

The Redline kit is crap.  The throttle arms, when bolted together, won't clear the boss right in front of the idle adjust.  The heim joints that are supposed to go on top of the manifold all have plastic bushings.  The final pivot points - at the throttle arms, are bolts inside heim joints - which might be OK, might not.  

 

Replacing heim joints is expensive.  After scouring the internet for heim joints and ball joints, I found everything to round out the kit.  Turns out the best place to find heim joints is Amazon.com, and the best place for quick release ball joints (RH and LH thread) is on e-bay.  Unfortunately, all the LH ball joints I found came from the UK, and were not cheap.

 

The bottom line:  It may be one stop shopping, but you are paying a lot of money for a kit that you'll end up doing a lot of work on.

 

PS - all of my orders from Ireland had problems.  The linkage kit had missing pieces.  When I called IE, they sent me the wrong pieces.  I ended up getting the pieces I needed from Pierce Manifolds, only to find out that to use them, I had to grind on the bosses on the carbs - at which point I abandoned using the Redline kit.  On top of that IE did not send me the water bypass pipe in my kit.  Both problems were solved after a few phone calls - but it was a pain in the ass.

 

Pierce Manifolds dual carb linkage kit

 

PROS:

Available in Right Side or Left Side mount (per carb).  I got Right side mount, so the throttle arms are on the right side of the carb.  

Ball joints at the pivot points.

Cool looking aluminum throttle arm mounts.

All of the heim joints are solid metal.

 

CONS:  

The heim joints that thread into the top of the manifold are 3/8-24.  That's different than the other kits, that are all 5/16-24.  So, if you get this kit, you are going to have to drill and tap your manifold.

 

The bottom line:

If you want a mechanical linkage kit, order the one from Pierce.  It's the nicest of the two I looked at, and will work without modifying your carbs.

 

So, here's what I will end up using:

 

Korman Engineering Intake Manifold (that I've had for years)

Pierce manifolds dual carb linkage kit (still generic, but oh well).

8 mm, 1.25 45 mm studs that thread onto this (bought via BoltDepot.com)

Redline soft mount kit

Italian Weber DCOE 40's

1-1/2" air horns (again from Pierce), inside of ITG Megaflow filter housings

 

And that's that.

 

I'll post a pic when the Korman intake gets back from the machine shop.

Edited June 7, 2014 by Kidasters

[2002dean]

Ken

So the Korman intake is different than the Ireland? Similar design but better quality casting?

Had you looked into the Korman linkage?

I've been talking to Carl and bought an oil pan and crank scraper from Korman. Carl seems extremely knowledgeable and is nice to talk to, but man they're not cheap.

Edited June 7, 2014 by 2002dean

[Kidasters]

I wouldn't say that the Korman piece that I have is a better casting.  But, the detail work is better.  The flange where the studs go to make up the carbs is 8 mm (vs 5/16 th on the IE piece).  The Korman piece that I have didn't need any polishing - the inside was already in really good shape.  The Korman stud holes are true - that is, if I install my 8 mm studs, the carbs slip right onto it.  The IE manifold and studs, not so much.

 

From a "flow design" standpoint - they are very similar.  There really can't be a lot of variations on 1 piece short intake manifolds for a BMW M10 engine.  There's not a lot of room to get creative.

 

I'm not sure on the Korman linkage.  I know they sell a kit.  I would ask very specifically if it's the Redline generic kit (aforementioned krap) or what.  I just wouldn't bother with it and go directly to Pierce and get their kit.  I know it is quality and it fits with no mods to carb, just mods to Manifold.

 

I understand that Korman isn't cheap.  But - is that cost just moved?  Buy the IE manifold, multiple trips to the machine shop (and time).  Mulitple times of monkeying around with it to get it to fit.  Or - pay a little more up front and skip a lot of that?  Pay now or pay later.

Edited June 7, 2014 by Kidasters

[TobyB]

From my experience with sidedrafts, Ken,

I'd say that sounds about right- you'll end up having to do it yourself if you want it to work right.

 

I used Cannon manifolds, which were quite good (I have several sets, and they're all good)

but the Cannon linkage way involves separate

pushrods for each carb- and that lets them drop out of sync pretty easily, if you use soft mounts the way you're supposed to.

Plus, you can bend throttle shafts if you're not paying close attention

(and I wasn't, at first, since the first setup came 'already running')

Then I used a center sync linkage out of a different kit I got in an attempt to improve things.

 

THAT kit sat on top of the carb bowls, and would have meant pulling the linkage every time the lids needed to come off,

plus some cables, so I used the stock pedal and linkage with the Cannon heim pivots, but re- linked it to a center push.

 

Your mileage varies, of course!

 

t

Edited June 7, 2014 by TobyB

[Stevenola]

Your carbs look great.

 

I found that an AFR gauge is vital to setting these up correctly and well worth the investment.  Eliminates wishfull thinking seat of the pants analysis.

 

Get your distributor recurved so you can set your idle advance at around 12-15 and total mechanical is about 20-22 so all in will be 32-34 or whatever your engine likes best.  Advanced Distributors knows what to do here.  Webers like advance early on and all in by 3k rpm or so.  A luxury is the 123ignition distributor which you can infinitely program on the spot to dial in max HP and torque on the dyno.  I love mine.  Don't overlook the importance of a correctly functioning distributor, especially with DCOE's and the age/condition of the distributor.

 

Once you know your idle, cruise, and WOT AFR's you can decide whether to change jetting. If you do I suggest buying the drill set from Pierce and jets smaller than you need then drill them out until your desired AFR's are met, this will save you a lot of money just randomly buying jets. 

 

Join sidedraft central on yahoo and download the White Paper tuning guide and the Weber Tuning Manual, these explain the theory of progression etc and how to tune each circuit.

 

Set your floats with them mounted in the car by using a dipstick through the main jet tube, measuring by the book with a ruler with the top off is not as accurate. Set floats and timing before messing with progression.

 

Once carbs are synced, set jetting with whatever filters your will use installed, this will affect AFR also.

 

As a starting point if you want, go ahead and post your choke, jets (idle, main, accel pump, air corrector), and emulsion tube numbers. 

Edited June 8, 2014 by Stevenola

[Kidasters]

Thanks Steven.  Yeah, the AFR gauge is already in the plan.  I've gotten an analog gauge to put in the "change" area to the left of the gauge cluster.  

 

I have an 002 dizzy that I will look into sending to Advanced to re-curve.

 

I'll peek in the carbs at some point and post my numbers, but before all that - the head has to come off!

[TobyB]

 

 

 drill them out

Personally, I am not a big fan of this method.  

 

Drills are not particularly precise hole- makers, and once you do drill,

then you have something labelled as a 125 that's really a 135.

You hope.

 

But I admit, I have a set of 125's that are drilled and reamed to 'about a 127.5'

because you can't buy a 127.5 anymore, and that's the best fit

for that particular motor at sea level at about 80 degrees f with avgas

and a barometric pressure of 29.5...

 

Jus' my '02,

 

t

[Stevenola]

Drills are not particularly precise hole- makers

 

True, but they are consistent, and I have received jets with slightly different diameter holes from suppliers before (i just received an idle jet with 2 fuel holes bored in it!) so the drill set will verify that all holes are same size, eliminating this variable from the equation.  And saves a lot of money.  Then once you are in the ball park AFR-wise, you can really get precise but you'll be so exhausted that you'll be happy with being close

[kbmb02]

True, but they are consistent, and I have received jets with slightly different diameter holes from suppliers before (i just received an idle jet with 2 fuel holes bored in it!) so the drill set will verify that all holes are same size, eliminating this variable from the equation.

 

Data point: I'm not sure if it's marketing or their way of discouraging the drilling of jets (so they can sell more), but I believe Weber states that the numbers on the jets don't always reflect an exact hole size, but rather the numeric flow of that particular jet. If true, it could explain the slight variation mentioned above.

 

That said, I drill and use 'in-between' sizes on the race car. Like Toby. -KB

[eurotrash]

For the record.  Yesterday on a long highway drive, I clocked 245 miles on the first 8.1 gallons of 93 octane with Dellorto DHLA40-H.  

 

It turns very rich as I get into the 5k rpm range and higher.  I suspect it be the crap ass used pancake filters.  Maybe.  that's the next hurdle.  

 

And then there is this logic...which is where I will head if proper filters don't remedy the choking at higher RPM.

 

https://www.youtube.com/watch?v=1pkFSA_rRFI

 

 

 

 

Edited June 8, 2014 by eurotrash

[TobyB]

If it's not the filters, that's the tuning range for your air correctors- IF you're at full throttle...

t

[eurotrash]

98% full throttle, I can't get the linkage to give me the last 1/8". Are you psychic?

And, I have 210 correctors installed. They carbs came to me with 200s. Maybe I should go a size bigger? Or two?

[TobyB]

Jesus, that's huge.  What mains?

 

If it's 'very rich' then do the filters first.

 

I seemed to end up 125 main, 150 air (or close) for 3 different engines with 4 different cams...

 

t

[zinz]

Couple things...

1st: Thanks, Steve, for the tip on the Yahoo group, SideDraft Central. I've sent a request to join. (BTW.. Ray has sent me pics of your CSi from the NOLA Cars and Coffee events... gorgeous!)

2nd: As for those pancake filters...meh... I struggled with all the choices for filtering my duals. I couldn't find/afford an original airbox and could justify the $$$ for an aftermarket one...

I went with UNI Filters http://www.unifilter.com/clamp-on/ and found the biggest filter I that would fit (Model# UP6245AST) This model has an 15 degree angled neck, so everything cleared the standard brake booster. It's 6" overall with an I.D. of 2 1/2" and a filter that's 4".

Your set up will likely be different (I'm using some vintage, Solex velocity stacks)

There are lots of choices out there. Ireland sells a UNI filter designed for the Weber airhorns, but the filter elements are shorter than what I bought.

You can look on the 1st page of this thread to see pics of the early fitment of my filters. They have an additional, red, pre-filter. Red for show, black for go...I haven't noticed any appreciable difference in performance with or without the prefilters...but I don't have a WBO2, either.

One other thing I did to my UNI filters...

The inner neck has a pronounced ridge (I'm assuming that it butts against the mouth of the carb stack) Well, the filter says 2 1/2" I.D. but the ridge is 2 1/4" right where you want a smooth transition into the velocity stack! I dragged out the Dremel tool and removed that ridge and now I have uninterrupted airflow into that big filter element and down the velocity stack. Here's before and after pics.

One other thing I did was to smooth out the ragged, brake booster vacuum port hole in the intake manifold. I filled it with JB Weld, then drilled it back out after it cured. Then smoothed everything with the Dremel and a sanding disc attachment. I only have the after picture. It's smoother than it looks in the picture, but still not highly polished.

Ed Z

[eurotrash]

Toby, here is the (copied and pasted) list of changes I made to the carbs after I ran them initially. They were uber lean. Didn't want to cruise, stumbled off ide, even stationary, etc. Even though they were on a 2L alpha in a past life..I didn't get the impression they ever worked properly on that car, mostly becuase someone tried to tune them as they would a standard DHLA.  The H 'emissions' carbs operate very differently than standard DCOE/DHLA logic.  There is no air hole in the idle air corrector, 5 progression holes, etc. And the idle jets actually feed of the main stack, NOT the float bowl..  (read the last section copied/pasted in below for  full explanation from the guys at www.dellorto.co.uk)

 

"..I went through and base-lined the carbs based on the range of tubes/jets listed in the doc that lists the types of DHLAs.  I swapped in .11 emulsion tubes, had .7s. Went up to 210 main air correctors from 200.  155 main jets from 135. 62 idle jets from 55.   I went closer to the rich end of the spectrum of what is recommended for these "emissions" carbs."

 

There are 15mm horns under the filters for flow correction, there is still over an inch of clearance in the filter.  but maybe that's restricting the flow?

 

Over all they are silky smooth on the street.  Gave me great torque and hp numbers on the dyno, as you recall.

 

But right now, they just don't like the high RPMs.  They go rich (11/12s on the AFM, assuming its the carbs..) and blow soot out the tail pipe.

 

 

Jesus, that's huge.  What mains?

 

If it's 'very rich' then do the filters first.

 

I seemed to end up 125 main, 150 air (or close) for 3 different engines with 4 different cams...

 

t

 

Explanation of the carbs. So far everything he talks about has been true, in my experience.

 

"Type 3 DHLA40F-G-H-N-R-S models. These are called emission completely different to the DCOE science, but noone really understands them and tries always to tune them like the early models. These differ because they have more progression holes and use the idle jet to feed most of the cruise phase and low rpm/low TP area of the engine AT ALL TIMES when the main jet isn't in operation completely automatically no jetting needed. The idle jet has a very large fixed 2.2mm air feed, you cannot tune this phase of the carburetor for length like the others, but here lays the secrets....

The idle jet doesn't feed from the float bowl, it feeds directly from the main jet stack, what happens after this is what gives these Dell'Ortos the sweetest road behaviour (what 25years of research came up with and not just for emissions) and dead easy tuning, you see when the main jet starts to emulsify fuel in the tube, the idle jet is feeding from it, so the gassy airy fuel shuts down the idle jet and sucks backwards yes BACKWARDS through the idle!! using every drip of fuel efficiently without ANY waste in circuit cross over where one is going after the other...this happens the moment the main jet fires, so there is NO need at all to tune the length of the progression and idle phase. This is pure magic they are automatically calibrated, you simply keep the idle jet above 59 up to 62 and not make the mistake of fitting numbers suited to the early DHLA or DCOE - with this simple technique you can tune anything from a 1300 to a 2000cc without really doing anything. The emulsion tubes in these carbs are always 8-10-11 and have to stay that way - which are really rich and have a hole straight down with loads of air holes, these atomise the fuel to an massive degree, also they have to be used cause the idle jet will not run correctly using the DHLA40-E type tubes (1-6-7-5) as the idle jet needs these airy tubes to function and cut out as designed...Usually people ram the DHLA40 idle holders with air holes in these carbs add the 1-6-5-7 style tubes and wonder why its a massive lean spot off idle, cause they missed the point completely!...These carbs use a .3 vent which has a very small signal tube to the main jet stack, this is because the holey tubes are basically ready to go from about 1250rpm (on my car using an 8tube 1 vent it was on the mains at 1250rpm!) so the holey tubes need holding back with a signal killing venturi...These carbs are wicked if you want bolt on power, they tune themselves!

The early types are better in respect of punch and tuneability on odd applications but dont' really do anything these late types won't on all but the best engines...I have run em all! These carbs will give the maximum power available on any engine if you take time to tune them right, but they are a bit more suited to standard motors over 1500cc, motors with mild cams or standard cams and they operate best if you are using 30-33 chokes, they hate race engines, mad cams and mad chokes cause they they are designed mainly for hot production engines with a clear pulse strength to suit the retarded venturi and tubes - great where silk town driving and alike is paramount and you do commuting or just sunday driving, they also give superior economy to the early types.

So the DCOE is the same as the DHLA40, but the DHLA40E and F-G-H-N-L-R-S are all evolutions of a principle and provided the application is matched to the carbs best qualities you have the ability to cater for everyones tastes and requirements using Dellorto."