32 w Webers dyno %233

Hot off the Dynojet drum:

Ferrari 3.2qv, 9.2CR, Weber 40DCNF, Stock Microplex ignition
New dyno data with the 36mm venturis, 145/F24/190/.55, stock cams:

SAE Rear Wheel HP: 235.9 @6600
SAE Rear Wheel Torque: 202.7 @5600

Flywheel SAE hp (18% driveline loss): 287.6 @6600
Flywheel SAE torque (18% driveline loss): 247.2 @5600

Max uncorrected (actual today) hp: 296.3

(Ferrari Factory specs, US Mondial 3.2 with Kjet: 260 SAE hp @7000, 213 ft-lb @5500)

idle A/F: starts off quite lean, but comes down to 15
A/F during 4th gear pull 13 - 14

140 and 145 mains, while producing basically parallel A/F curves a point apart, differed in hp figures only about 1 hp.

I think I have maxed out these stock emissions oriented K-jetronic cams and Microplex ignition advance with these carbs. I'm done for a while with the Webers, will now drive a bit and look at the ignition later to finish off the winter project.

Super thanks to all the great folks on this board who helped, especially JRV and David. This has been a hoot and great fun, and I've learned a lot.

best to all
rt

'fuel injection is for kids'

Gee Russ,
I have followed your progress on this project and commend you on your tenacity in getting every little bit out of your set up. When I get my shop built I'll feel more inclined to tackle a project of this scope.Hopefully next winter. I'll buy the book when it comes out. WOW

DJ

thanks
it's really not that hard.

I'd really be interested if someone has some A/F ratios of a dyno run or what they generally have during idle and cruising. While the the hp figures are about identical, the 140 and 145 jets have differing A/Fs. The 140 varies from 13 - 14 and the 145 varies from 12 - 13 on the pull. I left the 145 in as a little insurance, as sometimes the car will feel like it wants to go lean while driving, although the throttle response with the 140 *subjectively* feels a little better. I decided to leave in the 145s for the time being since my next project is to roll in more advance with the new distributor anyway.
Will try to post the graphs soon.

Please post or send any A/F data that anyone has from dynos or driving. That would help put things in perspective for me.

best
rt

Emulsion tube selection in the carb'd Ferrari V-6 and V-8

Since these emulsion tubes are stock in most V-6 and V-8 Ferraris, here is a brief amateur explanation as given to me on Ferrari 40 DCNF emulsion tubes. Early V-6 and V-8 Dinos had F24 emulsion tubes which were replaced in the later versions by F36s. While the main jet runs the overall mixture, these ET's fine tune the midrange air/fuel mixture much as the air correction jets provides fine control the top end A/F

The diameter of an F36 has more holes toward the top than the F24 making the F36 somewhat leaner, and was probably used to lean the mixture as Ferrari worked on emissions by leaning mixtures. These tubes are different diameters as well with the F36 having a larger air space. Ergo, the F36 will lean the midrange a little compared to an F24

My A/F in the 3000 - 6000 range is about 12 using the 145 main jet. One way I am looking at leaning a little bit is to replace the F24 with an F36. Since I am also going up in idle jet size, the midrange will need a bit of leaning from the additive effect as well. The target is an A/F of about 13 - 13.8. I have also found that a main jet size difference of 5 (like between 140 and 145) will have the effect of changing the fuel ratio about 1 point.

Would love to hear anyone else's experience.
I know hundreds of you have been losing sleep over this as I have.
rt

Russ,

My basic thoughts on your mixture concur that the F36 might be a better choice and I additionly think a move to a 200-210 AC jet might improve the AF Ratio and the power by a few ponies. Once the amount of fuel required is dialed in, then it's helpful to increase the amount of air to bring the mixture inline and produce more HP. The hotter and more complete the combustion charge the more HP one can extract. Haven't looked in my Dyno books, but something keeps telling me a AF Ratio around 12.5 - 12.8 is a good range?

Regards, JRV

Have you compiled any BMEP numbers? You'll need those to finish calculating the volumetric efficiency of the engine from this point on imo.

Regards, JRV

JRV
The number I hear bantied about is 13.2. Certainly the sl larger A/C will lean it out on top a bit and have wiggle room. I will probably look at doing that. They taught me the leaner the mixture, the hotter, but not necc. the most power.
I notice it really responds better if I keep it a bit leaner, but not neccesarily that much more hp. My target is to track at 12.5 - 13.8 and try to have it be on the high side at cruise.
My dyno tech thinks I am being way too picky andwe are really pretty good now.
Ordered from Pierce (Doug) today (we are on a first name basis now) and will tweak to 36mm/140/F36/200/.57
How about that for fine tuning - a .57 idle!!

No BMEP yet.

I am really not expecting any more hp, just max tuning for drivability and response.
That said, I do think I will bring up my mid range torque a bit with the distributor advance of 36 in by 3000 (as opposed to the stock 32.5 by 5000) when the new Mallory goes in. Am trying now to figure out how to index the distributor drive plug that goes in the cam.


Of course when the cams get back from Elgin, here we go again.....
It's a good thing I am having such a great time

thanks, and best to all,
Russ


Hey, David - you out there?

Hi Russ,
Being working and traveling like a crazy person...and need to catch up on my home stuff and sleep a bit. Just some food for thoughts...After the idle mixture is dialed in, you can they "adjust" the slope of the mixture versus RPM curve with the air corrector jet. Once you start switching emulsion tubes, all the rules and baselines change...so give this some careful thought before you jump.

I'll be home over the weekend..and we can, if you'd like, discuss this further. From what I've read, it looks like your very close to dialed in...

Regards,
David

David
Thanks a million. I wonder if I am getting too picky. After seeing the A/F from the stock 308 in the other thread where the Kjet held it a mid 14s the entire run, I now have a benchmark.

Will try to post the graph this week. Will probably settle on 36/140/F36/190/.57 and see what happens. Target is to run mid 13s all the time.

Dang, this is fun.

Russ,
Too picky?? You're talking to the right guy (nut?)...I have a bag of several pounds of DCOE jets in my garage! My first real serious Weber project was a B-sedan engine in my street car, an Alfa GTV. This engine was never destined for the street, but I was determined to use it, anyhow. Venoila 12.5 pistons, fully ported polished, CCed heads...knife edge crankshaft...with dual 45 DCOEs. I don't remember all the jetting specs, but do remember the main jet was in the 165-170 range, with a 140-150 AC jet. Yep, she didn't develop much power down low, but after 5000 PRM...Hold on!

I found out yesterday that the machine shop that did my BB engine work is getting a chassis dyno. Guess where I'll be in the Spring?

Although being picky (I prefer "attention to detail')setting up your carbs, sadly the jetting requirements will change somewhat with weather...and of course, if you make cam changes.

As to replicating the FI A/FR curve...It's just not going to happen, due to the design of the Webers, or most carbs for that matter.

The rules of life??
-A woman can never to be beautiful
-You can never be too rich
-And, you can never have enough HP!

Onward...
David