Thoughts on 40 DFI carb?

[RoyBatty]

I'd really like to meet up with you at a Fiat event sometime to compare our cars.
I've got the idf 40's on both my 1800 Spider and the 1600 BC Coupe and I don't notice any flat shots or non linear response in either of these cars.
There is no on/off switch effect to the throttle at all.
And I know that you are very experienced with all this type of thing as your write up in this thread proves.

[AndyS]

I didn't say the 40 IDF's I ran for many years had serious flat spots or on / off throttle. Just stating this 40 DFI does not.

The twin 40's I ran were fine most of the time. I did have a lot of trouble keeping them in tune though over time, and at one point bought brand new IDF carbs thinking my rebuilt ones were just not right, and still had a decent amount of problems with the new ones as well. Had issues with the pump jets dribbling gas at idle for no reason, had a needle and seat stick on me a few times and fill my combustion chamber with gas, and was always needing to fiddle with the screws to keep the carbs running right. Maybe it was all that alcohol in our gas here. that is why i finally took them off and don't care for that set up anymore. If you got a set up that runs good and stays in tune, that's great. The 40 IDF's still had more top end then this single 40 dfi has.

The 40 DCNF's I ran on a Fiat 128 had poor throttle modulation. they were like an on off switch on that car.

[AndyS]

Looks great and clean setup ... maybe I should have spent a bit more time with it!

I probably have about 10 hours of tuning and needed mods that I put into it, and another $75 in parts. Was a pretty challenging job to get it running right, but I was pretty determined to do give it a good try. I also think that without the performance mods and extensive head work my engine has, it may have been impossible to get it to run this good, as it is a very large single carb for a 1800 cc 4 cylinder engine.

Curious to see what my mileage will be and if it stays running like it is right now over time.

[bradartigue]

Now with a modified engine, I don't know. With the right camshafts and pistons none of this is an issue, but I'd still argue it is a lot of work to just run a different Weber.

Hmmmmm,
"Ar[ti]gue...
argue, ar-ti-gue.....
Interesting.
Guess we can't have one without the other.

Weird.

On the topic of the carburetor, the implementation looks great. Monster carburetor, I'm curious to know about how well it burns long term. If it works very well then I'm inclined to give it a whirl - duals on Spiders are a pain.

[AndyS]

back in the mid 90's, I spend some time in Australia and hooked up with the Fiat Car Club of Queensland. Pretty hard core car group down there, and they were the ones that told me the 40 DFI was a great carb on a modified Fiat twin cam - a lot of them ran that carb, and these guys did a lot of racing, autocross, rallies, etc. they also didn't skimp on their engine set up. My head was actually ported and polished in Australia by a master Fiat engine builder that they all used.

They could find those carbs used in the junk yard on some English made Ford Capris / Essex's that were sold there--over here, I had no luck locating one when I decided I wanted to try one and eventually gave up looking until recently. FAZA sold them as well back in the 70's, and there were some letters in his crazy books from people who were impressed with that 40 DFI. Of course, Al Cosentino made all kinds of claims, but some did turn out to be true.

someone named Beek here posted a while back he made more power on the dyno with the 40 DFI than with the twin IDF's. I linked his post. Been a while since I had the IDF's on there, but I can tell you my car pulls way harder than it did with the 36 DCD I had on there-and the car was already a pretty fast 1800 Spider. Must be making 15 more HP, especially right off the line --its not a subtle difference.

I have checked ebay australia, and haven't seen any listed there recently--that was 20 years ago when I was there, and I am sure the availability of this kind of stuff is way different now. probably should have bought one in Australia when I was there way back when! One did sell in the UK last month, and they do come up there from time to time.

There are 2 variations. the DFI-2 has 28mm chokes, and would better on a more stock motor or 1438. The DFI-5 is what I have, and works great on the larger engines that are modified to handle more flow.

http://www.fiatspider.com/f08/viewtopic ... dfi#p75098

[bradartigue]

You know the 1438 matched the largest carburetor installed on a Spider engine? A 34DFH was the original spec for that car. USA models got a progressive (26/34) DHSA1. The only other Spider that received this large of a carb was the 1974 1800 (34DMSA). The 1608 actually had a larger carb, at least one barrel was, the DHSA2 was 36mm on the secondary.

Point being, I'm not sure I'd go down a size with the 1438. It can take a lot of carburetor. If anything we were convinced by vendors years ago that the 40IDF was adequate for these engines, and I've never thought they were. Maybe as a starting point for a 1438, but they've always seemed small on a 1800 and 2000. Which is probably why I liked the 42DCNFs on the 2000.

If you're looking for a DFI search for Opel GT, Saab V4, Ferrari Daytona, Ferrari 365 (it had three of them - ha!)

[131]

My head was actually ported and polished in Australia by a master Fiat engine builder that they all used.

And who might that be?

[AndyS]

this was 20 years ago, and Jim Berry had it done for me. jim's shop was called Italia Spares I think. Not sure if I ever got the guy's name who actually did the work, if I did, long forgot it. Was probably in the Brisbane area.

I shipped some cars and parts to Jim Berry back then, in exchange for some bank wires and a couple of cool 1585 engines and a done up euro spec 1800 head. He also sent me one of his special performance clutches for the 124. Lost touch with Jim years ago. Maybe the cars I sent over are still around. One was a 1600 Osca, (at the time it was the only complete one in the country) and also a 1200 and 1500 Cabriolet.

Never been to Tasmania, but heard about a crazy race that was run there. Some of the guys I met from the Fiat club would take part in it, and had some war stories to tell about it.

[131]

Jim is still around.
http://raceclutch.com.au/
Targa Tasmania is still held every year. Pulls some big names, it's now priced out of the range for the average hobby racer.
http://targa.com.au/tc/page_standard.asp?asset_id=19237
And back on topic, I'm pretty sure AC historic runs a DFI on his 124, bottom left on this page.
http://www.petrolicious.com/9-photos-th ... assic-cars

[AndyS]

great to hear Jim is still around. we were trying to get an import export business together back in the 90's, but the Auzzie dollar took a hit at one point,and it made it hard to justify buying expensive cars and parts and shipping them all the way down to Queensland. He was also supposed to sell the cars I sent him at a big profit, and send me some of the money for the next round. he ended up keeping most of the cars I sent for himself instead! The Osca made a magazine cover if I recall.

we are planning a trip to Brisbane area in September. He doesn't still have a shop in the city does he? That city has gotten so much bigger since the 90's. was there 3 years ago for a short trip.

Looks like the Targa Tasmania is now like the Carrera Panamericana race in Mexico. Mostly just hard core folks with money to burn only at this point.

[131]

He doesn't still have a shop in the city does he?

Apparently so.

http://www.whitepages.com.au/business-l ... corner-qld

[AndyS]

looks like he is still doing his clutch business, but probably closed his Italian parts place. I will have to call him when I am there in September

[AndyS]

just wanted to post an update--the 40 DFI has performed flawlessly the past year. no fouled plugs, and the car still idles very smooth and pulls very hard with incredible low end grunt off the line.. I have not had to touch any screws or re-tune it even once. Gas mileage dropped a few MPG from the progressive 36MM dcd I had on there before, but I still get around 20 mpg mixed freeway and in town. About the same as i got with the twin IDF set up I used to run. plugs look clean and are not all black or anything.

I have looked around for another one of these carbs to use on a friends 124, but now have not been able to find one anywhere.

[AndyS]

just wanted to post another update on my 40mm DFI carb set up I installed a while back. Last year I blew the head gasket after over 20 years, and now that I redid the gasket, the car pulls even better than before. It blew out between 2 of the cylinders, so it was probably losing some compression for a while.

It really is too bad no one is reproducing this carb, as it is the best set up I have ever used on any of my Fiats. Yeah, it was a pain to get the linkage working right and get it jetted correctly. But the bottom end response is just incredible on my high compression + stage 1 street cam + full exhaust 1800 engine, which is what I really like in a street car. Especially with the steep hills we have all over the place here in the SF area. I also have not had to touch it or re tune it at all since i installed it a couple of years ago. with the twin idle circuits to dial it in, I was also able to get it to idle smoother than any other carb set up I tried before on this car.

Been looking for another one on and off the past couple of years with no luck. some crazy expensive one is on ebay right now from Europe

http://www.ebay.ie/itm/WEBER-40-DFI-5-F ... SwB09YGKCi

[BEEK]

I have used the 40dfi on my race cars through the years. I loved it much better than a pair of 40idf's. I have never tried it on the street, but i am sure it would be a lot of fun