# Dellorto main jet/emulsion tube/air corrector on 16v?



## 2lowcoupedoor (Mar 12, 2003)

I've got a 2.0 16v running Dellorto 45's? epjetta and I were trying to get it dialed in the other day had a little bit of success. Waiting for some new jets and emulsion tubes to come from the UK. 
Just wondering if anyone else is running a similar set up and what size main Jet? emulsion tube? air corrector? Any tips?


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## B4S (Apr 16, 2003)

*FV-QR*

Emissions carbs or universals?


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## 2lowcoupedoor (Mar 12, 2003)

*Re: FV-QR (B4S)*

universals I believe.


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## B4S (Apr 16, 2003)

*FV-QR*

The only real way to tell is to see if your idle holders have numbers on them. If not, they're emissions ones. Still tuneable, but require specific e-tubes. Regular ones won't work worth beans on 'em.


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## epjetta (Sep 19, 2006)

*Re: FV-QR (B4S)*

they do have numbers. we just need emulsion tubes that fuel a little sooner to take care of the dead spot that is there right off throttle. just looking for a baseline setup if anyone has a similar setup so we can save ourselves some time.


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## B4S (Apr 16, 2003)

*FV-QR*

What are the tubes in there now? The popular ones for non-emission carbs are .5, .6, and .7. What are they jetted with now?


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## 2lowcoupedoor (Mar 12, 2003)

*Re: FV-QR (B4S)*


_Quote, originally posted by *B4S* »_What are the tubes in there now? The popular ones for non-emission carbs are .5, .6, and .7. What are they jetted with now? 

.5 tubes, 170 mains, 185 air correctors.


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## B4S (Apr 16, 2003)

*FV-QR*

Sounds about right to me. The .6's are usually a bit 'leaner' than the .5's, although that's not really the best way to describle them. The .7's used to be the all-around tube, before they got hard to find. Eurocarb seems to have them now though. I can't comment on how the .6's would actually run, because I am on emissions carbs and they have a different series of tubes, so personal experience is limited. It was a dismal failure when I tried a set in my carbs, completely undriveable.
What are your issues?


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## 2lowcoupedoor (Mar 12, 2003)

*Re: FV-QR (B4S)*

pretty much undrivable. at any sort of low end throttle or any time I first give it any gas at all it has a lean bog really bad and wants to die then once it gets over that lean bog it drives ok. It's hard to make it up hills with out revving the crap out of it because of the bogging issue. driving on the freeway...forget about it cause it ain't happening. is there any thing else that controlls the fuel at first throttle that could be giving me this terrible bogging problem?


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## epjetta (Sep 19, 2006)

*Re: FV-QR (2lowcoupedoor)*

no it does not have .5 tubes it has .6 tubes. we need the .5 tubes to bring the fuel in a little sooner to take care of a lean condition off idle. he had .11 tubes to start with. i brought my .6 tubes from my 1.8 8v race car along to see what i could do with what i had.


_Modified by epjetta at 10:32 AM 5-19-2009_


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## 2lowcoupedoor (Mar 12, 2003)

*Re: FV-QR (epjetta)*

I just put in the new tubes and mains that I got in the mail today







. I am running the .5's right now.


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## B4S (Apr 16, 2003)

*Re: FV-QR (epjetta)*


_Quote, originally posted by *epjetta* »_no it does not have .5 tubes it has .6 tubes. we need the .5 tubes to bring the fuel in a little sooner to take care of a lean condition off idle. he had .11 tubes to start with. i brought my .6 tubes from my 1.8 8v race car along to see what i could do with what i had.

_Modified by epjetta at 10:32 AM 5-19-2009_

Uh oh...
If he had 11s in there to start, then they're probably emissions units. How many progression holes are there? 3 is universal, 5-6 is emission. Is it possible to take a pic of the top of the fuel bowl where the jets/tubes go without the jet cover on? It might be possible that someone along the way substituted the proper idle jet holders for the numbered ones. Was it driveable with the 11s in it? The emissions carbs need to use 9-12 tubes, and will buck and stumble like mad on the regular tubes. The emissions carbs need a HUGE idle jet, 58-62, to work at all. How many turns out on the idle mix screws are you?


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## 2lowcoupedoor (Mar 12, 2003)

*Re: FV-QR (B4S)*

It was pretty much the same with the 11's in it to tell you the truth. I am 2 turns out on the idle mix screws. I pulled the idle jets and it's running a 60, and the # on the top said 7850.9.


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## B4S (Apr 16, 2003)

*FV-QR*

Whew, universals







.
If you remove that star-head screw by the idle mixture towers, how many progression holes do you see? I'd be tempted to say that you need to get the idle mix to go a bit further as well as bringing the mains/e-tubes in sooner. If you've got more than 3 progression holes, then you might have to bump up the size of your idles slightly, and go with a 'leaner' idle jet holder. Also, possibly running a 200 air on the emulsion tube could help get the mains started a bit earlier and smooth out the flatspot. That's what I'd try first, after the tube swap.


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## 2lowcoupedoor (Mar 12, 2003)

*Re: FV-QR (B4S)*

There are 6 holes (5 smaller and 1 bigger) under each. 
How would I go about getting the idle mix to go a bit further and bring the mains e tubes in sooner?
What would you recommend bumping the idles slightly up to? they are 60's right now.
Is the idle jet holder the piece the idle jet clicks into that reads 7850.9? If so which one would you recommend me using.


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## B4S (Apr 16, 2003)

*FV-QR*

Ok, so it seems they're late model, non-emissions DHLA45s, you scored nicely on those http://****************.com/smile/emthup.gif. The long progression circuit (the 6 holes) allows the idle circuit to fuel quite far into the throttle position, since the fuel for cruise comes out of those little holes. 60 idles is already pretty big, so I'd leave those alone. I would leave the idle holder alone for now, and try out a larger main air, like a 200 or 220. The larger the air, the earlier the mains will start. 
Yeah, the idle jet holder is what the idle jets click into. Here is the layout of the idle jet holders from lean to normal to rich:
Weaker Normal Rich
7850.5 .10 .9 .4 .1 .3 .6 .7 .2 .8 
The commonly used holders are 7850.1, 7850.6 , 7850.2 and 7850.8. To extend the idle fueling a bit, go a bit richer on the holder, essentially moving the fuel curve up a bit. I'd try a .1, but only after experimenting with the larger main airs, and seeing how the new emulsion tubes help http://****************.com/smile/emthup.gif.


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## 2lowcoupedoor (Mar 12, 2003)

*Re: FV-QR (B4S)*

IM sent.


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## 2lowcoupedoor (Mar 12, 2003)

*Re: FV-QR (2lowcoupedoor)*

IT DRIVES LIKE A CHAMP!!!
literally all I did from this morning when I took it out and it drove like absolute crap was put my hood on, put my ITG filter socks back on, and richen my idle mixture by 1/4 turn. Maybe it was a turbulance thing with having my hood off and no filters just open stacks







.
It has a very very little hesitation when I first get on it sometimes but other than that it pulls hard all the way till redline!
Im running the .5 emulsion tubes now along with the 170 main jets...thanks epjetta for the help and B4S for the carb advice. 


_Modified by 2lowcoupedoor at 3:07 AM 5-20-2009_


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## MkIIRoc (Feb 20, 2005)

*Re: FV-QR (2lowcoupedoor)*

Whats done to the motor? Seems like large main jets. I ran 165's on gasoline.


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## 2lowcoupedoor (Mar 12, 2003)

*Re: FV-QR (MkIIRoc)*


_Quote, originally posted by *MkIIRoc* »_Whats done to the motor? Seems like large main jets. I ran 165's on gasoline.

The motor is completely stock. Do you think 170 main jets are too big for a stock motor? I have a set of 165's. What would the advantage of putting the 165's in apposed to the 170's?


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## MkIIRoc (Feb 20, 2005)

*Re: FV-QR (2lowcoupedoor)*

Yes, try some 145's. You will pick up power, use less fuel, and foul plugs less often.


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## 2lowcoupedoor (Mar 12, 2003)

*Re: FV-QR (MkIIRoc)*

Looks like i'll be putting in another order to dellorto.co.uk http://****************.com/smile/emgift.gif .
I'll get some:
-145,150 mains
-200,220 air correctors
Hopefully with those bigger air correctors it will get rid of that very little bogg I have on initial throttle. 
*Any thing else you guys think I should order so I don't have to pay $14 for shipping every time. *










_Modified by 2lowcoupedoor at 5:43 AM 5-20-2009_


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## MkIIRoc (Feb 20, 2005)

Hold off on the air correctors, I think 145 mains/180-185a/c will do you good. 
Air correctors won't get rid of the initial throttle bog. Tighten the accelerator pump linkage up a bit. Just a bit. When you hit the throttle, it should squirt fuel right away, no hesitation. If it leaks fuel at idle, loosen them a touch. That means the vibration of the motor is shaking the accelerator pumps and dribbling fuel out of them.
Or try turning the idle screws out a bit more.
The air corrector makes the biggest difference above about 5000 rpm. If you have a lean top end, but everything else is good, you need a smaller air corrector. smaller a/c = richer, larger a/c= leaner.
If you have a fat top end, you need a larger a/c.
If you have a fat top end and weak mid, you need a larger main and a larger a/c, etc.


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## B4S (Apr 16, 2003)

*FV-QR*

This is true, because the air correctors actually move the main jet fuel curve up or down in the RPM range. At high RPMs, the fuel doesn't stay in the etubes, so it mixes with the air from the corrector immediately before heading to the vents. The bigger the corrector, the more air, and the sooner the main starts. A good way to see this happen is to run a ridiculously small corrector and watch the transition from part throttle to WOT go to poop. Run a larger one and watch it get super rich at the transition. A larger corrector starts the mains early, and runs them out fast. The smaller corrector starts the flow late, and carries it on longer.
His carbs are Dells, so the acc linkage is actually on the bottom of the carb and pretty difficult to access without taking them off. To adjust the sensitivity, you have to move the nut on a teeeeeeeeeeeeny tiny shaft between the barrells, and there's no concrete way of saying what will happen when you do. There's no info on adjusting them, as well as the fact that there are two or three types of pump jet. One shoots down, and one shoots horizontally. The horizontal type are best for straighter manifolds, and the vertical ones are best for setups like mine (counterflow crooked manifold). My 38 horizontal jets barely provide enough shot, and the 42 verticals are waaaaaaaaaaaaaaaaaaaaaaay too much at times. On a straighter manifold, the 38s would be a ton of fuel, right up to a 2.0.


_Modified by B4S at 10:20 AM 5-20-2009_


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## MkIIRoc (Feb 20, 2005)

*Re: FV-QR (B4S)*

Yes I know, I used to run dells. I could adjust mine from the top, so a 16v should be able to as well. The accelerator pump linkage and operation is quite simple really. Probably why there isn't much info on it.
The nuts provide tension on the spring acting on the pump arm. Tightening these nuts increase the tension causing the pump to actuate sooner and with a larger shot. Removing tension causes the throttle linkage to turn further before the spring has enough tension to start acting on the pump arm, and only moving it a small amount. You can actually tune the pump quite alot with one set of pump jets. I added a washer on my spring stack and tightened it up pretty far on my race car with some small pump jets. Opening the throttle slowly 1/4 way would throw two streams about 2-3 feet immediately, and continue spraying until you stopped opening the butterflys.
The a/c can be used to tune main circuit crossover, but the emulsion tube will have an overall effect on low/mid/high mixtures, and needs to be tuned in conjunction with your main/air jet selection.
Here's some good info on the subject. The RX-7 guys have been playing around with them for a while. http://www.rx7club.com/showthread.php?t=805950
Problem is, tubes are expensive!


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## B4S (Apr 16, 2003)

*FV-QR*

I hadn't thought about adding washers...very interesting. I have cranked the nuts up on my Dells, but not too much further than how they came to me. I would like to get it firing a bit earlier if possible, mainly because I'm picky







.
I'd still start with the larger airs, IMO. In the Dellorto Superformance book I got from CB, there are listings in the back with a ton of OE applications from back in the day, and not too many of them run smaller than a 200 air. Sometimes they do use 180s, but not too often. My own experiments in tuning for my stock 1.8 setup showed me they're right on the money more often than not, except in the main jet choice (all hail widebands).
http://www.sideways-technologies.co.uk has a forum, and the admin (Davesideways) has to be the most knowledgeable Dellorto tuner I've ever seen. He's got all this stuff in his head in a big way http://****************.com/smile/emthup.gif.


_Modified by B4S at 11:31 AM 5-20-2009_


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## VdubyaVR6 (Mar 8, 2004)

*Re: FV-QR (2lowcoupedoor)*


_Quote, originally posted by *2lowcoupedoor* »_Looks like i'll be putting in another order to dellorto.co.uk http://****************.com/smile/emgift.gif .

How long does it take you to get your order from them normally? I emailed fastroadcars over there in the UK and they weren't sure how long it takes because of customs and all that stuff.


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## MkIIRoc (Feb 20, 2005)

*Re: FV-QR (VdubyaVR6)*

I buy from Alfa1750 on ebay, who is in italy. I live in california, and it takes about 12-13 days from day of shipping to hit my doorstep.


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## 2lowcoupedoor (Mar 12, 2003)

*Re: FV-QR (VdubyaVR6)*


_Quote, originally posted by *VdubyaVR6* »_
How long does it take you to get your order from them normally? I emailed fastroadcars over there in the UK and they weren't sure how long it takes because of customs and all that stuff.

I got mine in one week to the day!


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## 2lowcoupedoor (Mar 12, 2003)

*Re: FV-QR (2lowcoupedoor)*

Thanks for all the good info guys! I'm going to try a few things out here. i'll let you know what I find.


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## 2lowcoupedoor (Mar 12, 2003)

*Re: FV-QR (2lowcoupedoor)*

I just ordered my 200 and 220 air correctors from Alfa1750 on ebay for $30 shipped. On the Dellorto site it is $65 shipped. pretty big savings i'll say!


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## B4S (Apr 16, 2003)

*FV-QR*

Cool, Gabriele is a great seller, I've ordered MANY hundreds of dollars in jets from that guy, lol. He's always reliable with the shipping too.


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## 2lowcoupedoor (Mar 12, 2003)

*Re: FV-QR (B4S)*


_Quote, originally posted by *B4S* »_Cool, Gabriele is a great seller, I've ordered MANY hundreds of dollars in jets from that guy, lol. He's always reliable with the shipping too.

that's good to hear







.


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## 2lowcoupedoor (Mar 12, 2003)

*Re: FV-QR (2lowcoupedoor)*

So I recieved my 200 and 220 air correctors and tested them out. the 200's helped and the 220 helped even more with the bogging problem under initial acceleration, practically eliminated it....however my top end most definetly suffered from putting the bigger air correctors in. feels like it doesn't pull as hard up top like when I had the 185's in...is this normal? Is there anything I can do to help out my top end again and still maintain the 220 air correctors for the smoother transfer when I first get on the throttle?


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## candm (Apr 27, 2003)

*Re: FV-QR (2lowcoupedoor)*

your air corrector jets are for your top end. depending on your motor that would be anywhere from 5000 on up. up to about 3000 , is all idle jet selection, as well as, accelerator pump when you jam the throttle. also your idle circuit, 1000-3000, can be influenced by running your idle mixture screws leaner or richer, depending on how it is running


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## B4S (Apr 16, 2003)

*Re: FV-QR (2lowcoupedoor)*


_Quote, originally posted by *2lowcoupedoor* »_So I recieved my 200 and 220 air correctors and tested them out. the 200's helped and the 220 helped even more with the bogging problem under initial acceleration, practically eliminated it....however my top end most definetly suffered from putting the bigger air correctors in. feels like it doesn't pull as hard up top like when I had the 185's in...is this normal? Is there anything I can do to help out my top end again and still maintain the 220 air correctors for the smoother transfer when I first get on the throttle?









You could run slightly larger mains to richen it up top, and then switch back to 200s and see what happens.


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## 2lowcoupedoor (Mar 12, 2003)

*Re: FV-QR (B4S)*


_Quote, originally posted by *B4S* »_
You could run slightly larger mains to richen it up top, and then switch back to 200s and see what happens.

I'll try that. It drives decent now so I think i'll live with it for now, this thing is sucking my wallet dry







.


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