Would a 48 DCOE be appropriate for a Streetport 13B? Trying to size my carb so I don't have to swap out down the road.

 

That's a bit large...I gotta chart saved somewhere...I'll find it right quick...

 

.......................Weber.....Weber...Holley... Holley...Holley
Engine Porting...48 IDA...51 IDA...465.......600.......650
12A
Non-Ported .........NR..........NR.......155........NR....... ..NR
Street Port......... 165.........NR.......165........NR.........NR
Bridge Port......... 230.........NR........NR........250........NR
J-Bridge Port........240.........NR........NR........260... ....NR
Peripheral Port....270........280........NA........NA........ .NA
Peak Horsepower Output (HP)

13B 4-Port
Non-Ported..........NR...........NR.......165........N R........NR
Street Port......... 185..........NR.........NR.......195.......NR
Bridge Port..........NR...........255........NR........NR .......255
J-Bridge Port........NR...........265.......NR.........NR.. .....265
Peripheral Port.....NR..........300........NA........NA...... ..NA

13B 6-Port
Non-Ported...........NA............NA........NR....... 180.......NR

NR = Not Recommended
NA = Not Available

 

lol...nevermind...had my ideas crossed...

 

Looks like it would make approx 185 horses. How 'bout a good intake manifold? Where's the best place to look?

 

RB

 

Makenzie71, those numbers are for the IDA carb. He was asking about the DCOE carb. I'm running a 48mm on my stock port 13B, so I'd assume you might want to go with a 51mm for a street port.

Give Rob a call at RotaryShack. He can tell you exactly what carb is right for your setup. He really kicks *** and the best prices around. Hella fast shipping too.

 

that was the "nevermind" part...but I would only assume the results would be similar...

 

It looks like RotaryShack isn't in the business of selling parts. Their webpage includes project cars and engines, but no detail of carbs or anything. I'll give 'em a call, I guess.

 

no, click on "race products" then you have to go to the scroll menu. you probably just didnt see it. it's up there

 

Not convinced you actually need a 48, as I got great results with a 45 DCOE. Just don't go for the largest choke unless you are racing.

One thing worth considering with this that I just posted in tech support. Most recommend F11 emulsions. I reckon that a better choice is (need to check number) F3 which is same drillings but a narrower tube. This will make tuning the progression a lot easier, as the main jets will come in a little earlier and it is this that most have trouble tuning.

Bill

 

Bill for a 13B isn't a 45dcoe a tad small?

 

Well my 13B 4-port (pre-85) was getting 140HP at the wheels on an eddy dyno (so thick end of 160 dynojet HP) on a 45. All stock internals.

The carb fell apart in the end (literally) so I went EFI so never went as far as proving the top end. However I would say that, under 200HP a 40mm venturi should not be a limitation, especially if you knife edge the butterfly and cut down the spindle as I did.

Happy to be proven wrong.

 

Actually I asked because everybody else thinks that a 45 is too small for even a stock ported 12a.

I run 36mm venturis as per my 12a SP engine's break in to prevent me from stepping on the gas too much, I'll switch to 38mm once it's ready like in 350miles more.

 

Like I said, happy to be wrong, but IIRC the drag sport article had over 200HP from the Mikuni 44 (need to check at home as TWM have moved the download) and the 48 dellorto was giving 211.

It pays not to go bigger than you have to on carbs if you want good manners.

 

good info bill...

 

Just checked. Mikuni gave 207 peak on the engine dyno vs 211 for the 48 DCOE. In fact it was 5-8HP down from about 5000, but above the EFI setup until 6000RPM

However I haven't plotted the torque curve to get the full picture.

Conclusion. If a 45DCOE or 44PHH comes up cheap AND you or a good friend know how to tune it, then you will get close to the best out the engine.

YMMV blah blah

Bill