Fitting New 40 IDFs

[Corydon]

Hello fellow Spider enthusiasts,

I have been the happy owner of a 1974 CS-1 US-model for 25 years. The original 1756cc engine was replaced by a brand new 2L engine for a Ritmo (Strada) 130TC, many years ago. I kept the stock (or similar) single carb and the stock exhaust. It was adjusted on a "rolling road" and put out 113 HP at the time. I am finally going to give it the carbs and exhaust that it deserves . My plan is to install the following:
- Dual 40 IDFs (Made in Spain) (With choke)
- K&N "Lunch-Box" filters
- A swept-back, Alquati look-alike, intake manifold
- Facet fuel pump
- Malpassi Filter King pressure regulator
- Compu-Tronix distributorless ignition system (partly to avoid collision with intake manifold)
- 4-2-1 Abarth exhaust from Spider-Point.com

Any comments/suggestions on this are more than welcome.

Here are my questions: I am being told by two Weber suppliers (Germany and UK) that I will need to machine down the spindles and nuts where the two carbs meet, in order to be able to mount them on the intake manifold. Have any of you done this before? What exactly must be done? Will there be problems with linking the two carbs together after the "operation"?

To solve the linkage problem I am planning to do as suggested by Kendickson http://www.kendickson.com/car/idf/idf/index.html
Do any of you have other suggestions?

I am also in doubt what to do with the crankcase breather tube. It doesn't seem to be possible to attach it to one of the air filters. In some of the comments here I have seen suggestions to install a small K&N look-alike filter on the end of the hose. Will that be OK? Will there be oil fumes coming out of the filter, making the engine compartment dirty? Or will there be other problems with this set-up? Do you have other suggestions to solve this problem?

I have found the set-up parameters for the DCOE carbs originally installed on the 2L 130TC Ritmo engine. They look like this:

Primary / Secondary
Venturi 32,0 mm / 32,0 mm
Main Jet 138 / 145
Air Correction Jet 175 / 190
Emulsion Tube F41 / F41
Idle Jet 58 / 54
Idle Air Bleed - / 180
Accelerator Pump Jet 35 / 45
Accelerator Pump Delivery 3.5 cc per 10 strokes
Fuel Inlet Needle Valve 1.5 mm
Float Setting 6.75 to 7.25 mm
(don't think I understand all of it, though)
Is this how I should order the two new IDFs?

I am really looking forward to this upgrade and hope I will get a much more "lively" car. Hopefully some of you experts here will be able to give me advice on this. I have read lots of the threads and I see that there are some very experienced and knowledgeable folks here.

[RoyBatty]

Best advice I can suggest is to read everything you can find I this site using the search feature with "idf"as your search word.
There is no shortage of information around here.

[narfire]

Hopefully someone here has put the 40's on a 2L and can fill you in. I know some have the 44 IDF's on the 2L. Have you considered the 44's over the 40's? with the 2L.

[Corydon]

I have read all I could find on here and found a lot of good information.

I have considered the 44 IDFs, but as far as I can gather, the 40 IDFs should give better driveability on a relative stock engine.

[sydh70]

I have the same issue as I have bought twin 44idf new (Spain ones) for my 130TC block fitted to my 124 coupe (CC).
I know the waffle manifold requires the carbs axis to be cut. What I have been told too is that the waffle manifold is too restrictive and it is a reason why I could sell it and buy the Allison steel manifold. Just need to be convinced it will flow gas better...

Sylvain

[Corydon]

I have now been studying all the guidelines that sptcoupe has posted on IDF tuning. Brilliant stuff!

This is what I have narrowed it down to when it comes to how I am going to order my new 40 IDFs:
Main jets 130 or 135
Air corrector 190 or 205
Idle 52 or 55
Emulsion tube F11
Choke (venturi) 32 mm
Aux vent 4.5
Floats 32mm open and 10 mm closed
Needle valve 200
Bleed back 00 or 35
Accelerator Pump jet 55

Would this be a good starting point? Comments are welcome.

[131lover]

Hi Danisch neighbour!
I have a dyno and jetting for a 2l with the same engine but with high comp pistons, the notorious 8mm dome that everyone says is to much comp but thats not the topic here!

I dont know how to post it here, its a PDF, but i can email you it if you want?
fiatfiat@live.se

Perhaps the jetting is Close with the only exeption of the comp..

Alf
Sweden

[PininF]

Got my 40's about a year ago now from our good friend Csaba…

Waffle Manifold
Postby vandor on Wed Oct 24, 2012 3:41 pm
With the waffle and the IDF you have a separate runner for each cylinder, the best setup for performance.

We fitted them on my original 1800 Waffle Manifold without any linkage problems…Only thing i don't like is the gas cable sticking out and high ( due to right hand drive conversion ) so still need to do something about it…
Other than that I absolutely love the sound and performance especially when you open them up.

Hope the photo's help
Cheers

[fiatfactory]

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[PininF]

Here just a few more photo's and info on the topic,
It shows how the Waffle Manifold can easily be modified…Looks like one hell of a setup

http://www.guy-croft.com/viewtopic.php?f=5&t=1896

[Corydon]

@PininF. Thanks for the pics. They are worth more than a thousand words. It does not seem like you had to machine down anything where the two carbs meet. I am wondering if your carbs are 40 IDF 13/15 or similar. The only new ones I can find (Made in Spain) are 40 IDF 70. And they are supposedly a little wider, causing the clearance problems on the OEM style manifold (and other manifolds, like the one I recently purchased in Italy on eBay).
The only manifold I have found so far, which is designed to take the newer 40 IDF 70s, is the one Mark is selling.

The small filter you have sitting there in the rear left corner of the engine bay, is that for the crankcase ventilation?


Karsten

[Corydon]

It allows the carbs to sit level (F to R) when mounted on the engine in the car ... the steel one offered doesn't appear to have this feature buit in. Note the pic posted by PiniF ... showing the carbs from a side view... the runner at 4 is taller than the runner at 1, to allow for the natural rearward tilt of the engine as fitted in the car... keeping the carbs vertical is vital to getting them tuned correctly.

As far as I understand from Mark, his manifold also angles down towards the front just like the original manifolds. As opposed to the one I got from Italy.

[sydh70]

I have been told too is that the waffle manifold is too restrictive and it is a reason why I could sell it and buy the Allison steel manifold. Just need to be convinced it will flow gas better...

As I've said before, you can just open the OEM alloy manifold up under the carbs, then the butterflys won't clash, and the car will run. But for 'ultimate' performance (i.e. air flow as an engine is simply a glorified air pump) the manifold needs to enlarged right at the bend.
SteveC

What I know about airflow is just what I have learnt at my engineering school, so general matter. If you can do the job and you are interested I could send you the manifold (PM for "details") as I don't feel able to do it myself.
Otherwise I don't know what I'll do.

Sylvain

[PininF]

@PininF. Thanks for the pics. They are worth more than a thousand words. It does not seem like you had to machine down anything where the two carbs meet. I am wondering if your carbs are 40 IDF 13/15 or similar. The only new ones I can find (Made in Spain) are 40 IDF 70. And they are supposedly a little wider, causing the clearance problems on the OEM style manifold (and other manifolds, like the one I recently purchased in Italy on eBay).
The only manifold I have found so far, which is designed to take the newer 40 IDF 70s, is the one Mark is selling.

The small filter you have sitting there in the rear left corner of the engine bay, is that for the crankcase ventilation?


Karsten

It's a custom made smog unit…can take a few photo's over the weekend if you like.

[fiatfactory]

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