42 DCNF's on a Mopar 440

[enigma57]

Do you know of anywhere With good Weber flow- data?

Sorry, Caprimaniac...... Stopped by the forum here just now and realized that I did not answer your question regarding flow data in my earlier post to you.

Regarding actual flow data for Webers, the only source for that would be as Nick suggested...... To actually put a particular style Weber carb such as the DCNF on a flow bench and if it is one having various throttle bore sizes and interchangeable chokes (various main venturi sizes) as the DCNF has..... To flow each individual throttle bore size with each of the respective choke sizes that might be fitted to it. The reason there is not a lot of flow data on these carbs is that carbs on IR intake are generally determined first by choke size and then appropriate throttle bore sizing is determined to complement the choke sizing.

Flow data might be of more use with carbs designed for plenum style intakes. Weber does have in their books, a generic graph for suggested choke size on 4 and 6 cylinder engines operating on plenum style intake and having a 5,000 RPM redline. It is based upon aggregate airflow requirements as determined by total engine displacement of a multi-cylinder engine served by a single choke. Using this graph, you can come up with a pretty good idea of what size single choke would be required to supply a given engine size to 5,000 RPMs. However, this graph is only applicable to smaller displacement engines unless you utilize multiple chokes to supply larger aggregate displacements, making that determination by interpolation.

Weber also has a graph for IR intake (single choke supplying a single cylinder via isolated runner, no plenum) and it is based upon displacement and RPMs with allowances for street driven versus larger race oriented choke sizing, as I recall. These provide a good rule of thumb generally, but ofttimes OEM choke sizing will vary somewhat in actual practice due to a given engine design's particular architecture and airflow requirements. Same for more highly tuned rally and full on race engines. The books and graphs are a good place to begin, but each individual engine in each vehicle application, whether it be a road car, a rally car or a full on race car will need to be run on the road or on the track as the case may be in order to sort out what works best for each.

Hope this helps,

Harry

[Grant007]

Well you lot certainly know your Onions you Carb Freaks, I know I like DCNF's a real lot and without the information out on the internet and the extremely helpful knowledge of Harry, I dont think I would have been able to get my project underway without him as there does not seem many out there that still have as much interest in these old things anymore, so a big THANK YOU to Harry and all of you
Thank you again Harry and any other input on this thread, I have added a few Pics below of my collection/obsession with these wonderful Carbs, I do have 1 more set but they are currently on an essex Manifold and so therefore they could not be included in the line-up!!!
I have fully restored two sets of 3 here below, the other 2 sets of 3 are as I got them so far, but they are on my "To Restore" list.
the first set I done I poished them and cleaned them as best I could be hand, the second set that are more of a Silver colour I had cleaned with a Process called "Vapour Blasting", this is a gentle process that was developed and used on Alloy Aircraft part's and leaves a wonderful "As New" finish
I have only placed them on the manifold in the pics below for the Pics, I will now begin my Manifold Fabrication works that Harry as instucted me with and will be back for sure to show the finished article before fit it to my engine.
I have also included a couple of Pics of the Mopar 400 they shall be being fitted to.
The Rocker Valve covers are only a couple I had laying around to protect the Valve Gear, I have the original ones that are Alloy and have the inscription "JENSEN" and I am just polishing them now, I shall add update the thread as we go along







With my regards
Grant

[enigma57]

Outstanding collection of DCNF carbs you have there, Grant! And beautifully restored to better than new appearance and function. As someone who enjoys tinkering with DCNFs, I must admit to being somewhat in awe of your collection.

Look forward to seeing your intake when you have it done and hearing how your car runs with this one off setup.

Thanks ever so much for the E-mail update and photos. Will respond to your E-mail message later this evening.

Best regards,

Harry

[enigma57]

Randy, as a young child in the early 1950s, my Grandfather taught me to read and to write in English before I started grammar school here in Texas. And that is how he taught me. The old way. I did have one teacher (3rd grade) who insisted that I spell centre...... As 'center'. And I remember to do that when writing now, but as for the rest...... Old habits die hard.

Best regards,

Harry

[Caprimaniac]

[quote="enigma57]Flow data might be of more use with carbs designed for plenum style intakes. Weber does have in their books, a generic graph for suggested choke size on 4 and 6 cylinder engines operating on plenum style intake and having a 5,000 RPM redline. It is based upon aggregate airflow requirements as determined by total engine displacement of a multi-cylinder engine served by a single choke. Using this graph, you can come up with a pretty good idea of what size single choke would be required to supply a given engine size to 5,000 RPMs. However, this graph is only applicable to smaller displacement engines unless you utilize multiple chokes to supply larger aggregate displacements, making that determination by interpolation.

Weber also has a graph for IR intake (single choke supplying a single cylinder via isolated runner, no plenum) and it is based upon displacement and RPMs with allowances for street driven versus larger race oriented choke sizing, as I recall.
Hope this helps,

Harry[/quote]

Hello Harry/ Grant et al

Very Nice Collection of IDF's there, Grant. Correct airhorns and all....

I sit here With the Passini book, and find two tables therein.... I Guess the first one is the first you refer to? That table has engine volume, 0- 2,5 litres, VS main venturi diameter (one single barrel, 1- 6 cylinders, max Hp at 5000 rpm). The "how to use this chart" is a bit vague, but you're supposed to find venturi size on engines with differen number of sylinders and varying capacity.

Anyway, I see the plenum VS IR- matter and CFM numbers. It's been coming up on some discussions I have had here (With you earlier?) or a customer or a friend where the idea- like here- have been to use webers on plenum manifolds.

As on the Essex V6... using a single 48 IDF (or IDA) longditudal (as Ric Wood once tested "good") or two 38 DGAS (as the UK V6 Company "Car clinic", on a plenum manifold. Relate this to the common 390CFM 4- barrel setup. Will the HP potential be about the same? Will the flow be enough for a 7000rpm (max Hp) cam? etc.

The other chart is the same one as you refer to for IR setups. And as you say, it's highly individual, but a starting point.

Refering to the 347 I'm running now, cylinders are 700cc and the cam gives max Hp at (around)7000. According to this chart, - and it IS race oriented- it would need aprrox. 48mm main venturis. And 55 Bergs or something... It would have been interesting to test this on a dyno; 48/ 40 venturi VS 55/48 venturi.... What difference in the Hp and tourque Charts??? Max Hp? Transition area? Out of the corners?
(All I know is that the engine runs good with the 48's, but better with a 1000 CFM injection setup as I have run the last year- all other things kept equal (sorry for turning my back to the weber CARBURETORS, guys...))

When putting CFM numbers in engine simulation software (like Desktop dyno), as my 8 IDFs are used, would a good CFM Guess be 8 x 300= 2400CFM be a good approximation?

These are some of the areas where I'd like to see flow Charts (and dyno comparrisons) for the Webers. Although I would have not hesitated putting a single 48 on the Essex or 3 IDF's on a V8 and go on experimenting with jets and venturis....

Hope you post up Your results with the 440 Mopar, Grant.
(BTW- would like to hear more about Your Capri's. Do you run in some of the historic series in the UK, maybe???)

Nighty, night. fellows.

[Grant007]

Hi All again
I am just getting some stuff together and shooting off for a week away in Spain with the wife, I am taking my Lap top with me and I will respond to yourself CapriManiac and yourself Harry to your next installment of email thank you so much for that again Harry
Be back with more Info really soon
Grant

[enigma57]

Have a great vacation and let us know how your project is coming along when you have time, Grant.

Best regards,

Harry

[enigma57]

Randy, I have a friend 'down under'. She came to visit in the mid-'80s and we shared quite a few colloquialisms. Took me a while to pick up on 'tucker' and 'bonzer' and 'fair dinkum' and such. She is from New South Wales and she told me that 'Mexicans' meant anyone from South of there, so I introduced her to some real people from Mexico and we had some Tex-Mex food. My biggest difficulty was in explaining that she shouldn't call me 'Yank'. I am from the South and we fought a war with the Yankees and so I had to go over the history and explain to her why 'that dog don't hunt'.

Regarding colloquialisms and customs held onto from times past...... Up in the Texas hill country where I went to high school, we would say, 'Put 'er to the wood!' when the Sheriff's deputies would chase us to the county line...... Even though most of our cars were new enough to have metal floor pans rather than wooden floor boards.

And we still speak of 'big wigs' even though its been a very long time since men of high station wore powdered wigs and the higher their station, the bigger their wig.

My Aunts when addressing a birthday or holiday card to me as a young boy, addressed it to 'Master Harry B******' until my 13th birthday and then it was 'Mister'.

Best regards,

Harry

[enigma57]

Hi, Caprimaniac!

Regarding the 3.0 litre Essex V-6, I have no hands on experience with them so can only relate past experiences with engines of somewhat similar design and displacement in general terms. As Grant has quite a bit of experience with these engines, I am sure he can help you more than I with the specifics of what these engines like in various stages of tune.

Here is some info I found this evening regarding the Essex V-6...... I found the first link to be quite interesting in that it gives some information on tuning a single Weber 40 DFI-5 carburettor having 32mm fixed chokes to suit the 3.0 litre Essex V-6.

http://www.tubetvr.com/essex.html

http://www.ricwood.com/essexv6.html

http://www.burtonpower.com/tuning-guide ... guide.html

http://www.essexengines.com/tuning%20th ... ge%204.htm

http://www.the-man-shed.co.uk/articles- ... sex-v6-3l/

Regarding your 347 which redlines at 7,000 RPMs and is fitted with Weber 48 IDAs on IR intake...... Personally, I see no need to go larger than 38mm chokes on a street driven engine. On a semi-race engine requiring good throttle response off idle and at part throttle coming out of the turns, 40mm chokes on 48mm throttle bores would be as large as I would suggest in this situation. 42mm chokes can be fitted on 48mm throttle bores whilst maintaining proper fuel metering, however I believe your engine may actually get around a road race track faster with 40mm chokes if there are the usual tight turns to deal with. Whomever accelerates out of the turns faster and positions themselves well for the run down the straights will have an advantage on that type of course.

I came on board Dan Miller's EMC team initially to help him sort out emulsion tubes and jetting with the 51.5 EMPI IDA clone carbs he had on loan from a VW racer. I believe we could have placed even better that year, had we a set of 44mm chokes (366 cu.in.early hemi redlined at 7,500 RPMs).

After we placed 3rd overall at the 2009 EMC, Dan bought me a copy of "Four-Stroke Performance Tuning' by A. Graham Bell. Very good carb tuning info there, although the EMC rules were changed for 2010, forcing anyone who wanted to be competitive to come up with an EFI setup.

One thing we did when designing Dan's EFI intake for 2010 was to size port runner CSA to provide average velocity at 100% VE of 300 ft./sec. at designed redline (Our goal was 300 - 315, as our port would stall at 315 ft./sec. velocity.) Your 347 engine at 7,000 RPMs will have 301.62 ft./sec. average velocity at your present redline with port runners of 2.80 sq. in. CSA (which equates to the cross sectional area of a 48mm circle). So your 48mm throttle bores should be spot on if your port runners maintain the same CSA throughout.

If you care to experiment with larger chokes, I can give you some baseline settings (interpolated from pages 118 and 119 of Mr. Bell's book and from settings we used with Dan's engine in 2009). These should get you close enough to run the engine and you can fine tune from there......

Chokes - 40mm
Aux. venturii - 4.5
Emulsion tubes - F7
Main jets - 155
Air Correctors - 150
Idle (slow running) jets - 60F9
Pump jets - 50
Pump bleeds - closed

Chokes - 42mm
Aux. venturii - 4.5
Emulsion tubes - F7
Main jets - 160
Air Correctors - 140
Idle (slow running) jets - 60F9
Pump jets - 50
Pump bleeds - closed

Hope this helps,

Harry

[Powertrip]

Grant, couldn't help but notice that you have a 440 Source water pump on that big block? Be aware that builders were having overheating problems using those water pumps due to small internal passages. I don't know if they have since fixed the problem.

[enigma57]

Good catch, Powertrip! I am sure Grant will appreciate this info and take whatever remedial action is required.

I was unaware of this. Its been many years since I built a big block MOPAR and these new aftermarket pumps and housings were not available back then. I took your lead and did some reading on this and it appears that the 440 Source water pump is not so much the problem as is their water pump housing?

...... well as for my engine running hot, the water pump housing was the cause of it, in the back of it the water port openings were much smaller then the ones in my factory housing, really couldnt tell by looking , had to put my finger in the water ports to feel the difference......

http://www.dodgecharger.com/forum/index ... =60599.250

That being the case, I suppose one could pull the new 440 Source water pump and pump housing...... And either install the new pump on an OEM housing...... Or drill or hand grind the undersized water ports in the new 440 Source pump housing out to OEM size and then reassemble?

Best regards,

Harry

___________________________________________________________________________________________________________

'We'll Meet Again'...... Vera Lynn......

http://www.youtube.com/watch?v=0a__JhzsTtI

[Powertrip]

Actually, both the water pump (impeller) and the housing (small inlet passages) were in question. Personally,I would port the housing to match factory passages, and use a stock type impeller untill I had the exotic intake tuned up.
I wouldn't want to blame possible overheating on chasing a tune.

[enigma57]

That's makes perfect sense, Powetrip. Always use the best that you can get when it comes to parts, especially when it comes to cooling and oiling. No use risking a $10,000 or $15,000 engine over a couple hundred bucks worth of parts, especially in those areas.

Best regards,

Harry

[Grant007]

[quote="enigma57]Flow data might be of more use with carbs designed for plenum style intakes. Weber does have in their books, a generic graph for suggested choke size on 4 and 6 cylinder engines operating on plenum style intake and having a 5,000 RPM redline. It is based upon aggregate airflow requirements as determined by total engine displacement of a multi-cylinder engine served by a single choke. Using this graph, you can come up with a pretty good idea of what size single choke would be required to supply a given engine size to 5,000 RPMs. However, this graph is only applicable to smaller displacement engines unless you utilize multiple chokes to supply larger aggregate displacements, making that determination by interpolation.

Weber also has a graph for IR intake (single choke supplying a single cylinder via isolated runner, no plenum) and it is based upon displacement and RPMs with allowances for street driven versus larger race oriented choke sizing, as I recall.
Hope this helps,

Harry

Hello Harry/ Grant et al

Very Nice Collection of IDF's there, Grant. Correct airhorns and all....

I sit here With the Passini book, and find two tables therein.... I Guess the first one is the first you refer to? That table has engine volume, 0- 2,5 litres, VS main venturi diameter (one single barrel, 1- 6 cylinders, max Hp at 5000 rpm). The "how to use this chart" is a bit vague, but you're supposed to find venturi size on engines with differen number of sylinders and varying capacity.

Anyway, I see the plenum VS IR- matter and CFM numbers. It's been coming up on some discussions I have had here (With you earlier?) or a customer or a friend where the idea- like here- have been to use webers on plenum manifolds.

As on the Essex V6... using a single 48 IDF (or IDA) longditudal (as Ric Wood once tested "good") or two 38 DGAS (as the UK V6 Company "Car clinic", on a plenum manifold. Relate this to the common 390CFM 4- barrel setup. Will the HP potential be about the same? Will the flow be enough for a 7000rpm (max Hp) cam? etc.

The other chart is the same one as you refer to for IR setups. And as you say, it's highly individual, but a starting point.

Refering to the 347 I'm running now, cylinders are 700cc and the cam gives max Hp at (around)7000. According to this chart, - and it IS race oriented- it would need aprrox. 48mm main venturis. And 55 Bergs or something... It would have been interesting to test this on a dyno; 48/ 40 venturi VS 55/48 venturi.... What difference in the Hp and tourque Charts??? Max Hp? Transition area? Out of the corners?
(All I know is that the engine runs good with the 48's, but better with a 1000 CFM injection setup as I have run the last year- all other things kept equal (sorry for turning my back to the weber CARBURETORS, guys...))

When putting CFM numbers in engine simulation software (like Desktop dyno), as my 8 IDFs are used, would a good CFM Guess be 8 x 300= 2400CFM be a good approximation?

These are some of the areas where I'd like to see flow Charts (and dyno comparrisons) for the Webers. Although I would have not hesitated putting a single 48 on the Essex or 3 IDF's on a V8 and go on experimenting with jets and venturis....

Hope you post up Your results with the 440 Mopar, Grant.
(BTW- would like to hear more about Your Capri's. Do you run in some of the historic series in the UK, maybe???)

Nighty, night. fellows.[/quote][/quote]

CapriMan
I will get back and answer this in more Depth, I have always had Capris and shall add some Pics, I dont race them but love them and have them, I have a special one that may interest you, but I am away and dont have the pics with me to add, but I will sort it for your interest Mr Man
Hang on Mr Maniac Man
Grant

[Grant007]

Grant, couldn't help but notice that you have a 440 Source water pump on that big block? Be aware that builders were having overheating problems using those water pumps due to small internal passages. I don't know if they have since fixed the problem.

PowerTrip, thank you so much for spotting that, it triggered my memory into remembering something about someone who built a 440 Stroked to 8litre's,(Jensen) the Eldenbrock pump caused his probs,they seem to be good for high Revs and not low!! I will now pull the housing again and check it out, also I am going to change the pump as the one I am using seems to be something that will cause me problems, luckily I have a different type with the older stly impellers
Can I thank you again for keeping me posted with this issue Mr Man
With my kind warm regards and thank you's Powertrip
Grant