Ok I came up with a deal from a friend of mine. He has 2 Weber 40DCOEs that he will lend me for a "while" that where in his modded CRX and I am thinking about getting the TWM twin weber intake.

My question is regarding $:

The TWM dual intake is $375 in Top-end performance

The lake cities single intake is $250 in atkins

I can get the dual 40s for free.

I have to purchase one new weber 48 or bigger for the single setup.

note:
I'm running a stock port, one engine getting street ported and later on a bridge, all 12As.

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The question is which would be a better choice regarding $ vs driveability and power, the single or the dual intake?

1)
Please keep in mind that even though I can save $ with the dual setup (free carbs) and it will look and feel awesome. The tuneability of it is my main concern...I would be alone on this one since I hardly see that setup, nor do I see the right combinations of jets, bleeds, etc posted or listed anywhere...

2)
The single setup is much simpler yet I still would have to get a larger carb like over 48mm for the street port and also rejet.

 

im running the dual on my drag car...got it at nopi. we are also fitting a set of 50mm webers on the intake and a hell of a lot of nos. this is on a j bridge 12a ... but its not done yet but when it is hold the hell on

 

BadAssRx-7 you got any pictures of your dual system?

Is the one sold at NOPI the same intake as the TWM one? how much is it?

Thanks!!! ....now I know who to pm to give me some tips on tunning!

 

If I was you I'd save up and spend $800 on a complete downdraft 48IDA. You'll spend a small fortune on calibrated parts for the two 40's, and new intake manifolds aren't cheap either.

 

nimrodTT tell me where to get a complete downdraft 48IDA with intake for $800 and I will!!!

just a 48IDA copy by Berg is $1000 and the intake is costing about $300-$250 do the math. If you say used then it's ok (well not really)...but man I can't get a hold of any now days.

 

When I originally posted info about Top End Performance's dual 40 dcoe setup to the 1st gen list, it was posted as a complete kit, already jetted for a stock 12a. I think it would take a lot of time, $ and frustration to jet some crx 40 carbs for a rotary. What emulsion tubes? Fuel jets, etc..... That really is too much carburation for a stock 12a. I think you'd be better off getting the Lake Cities mani and buying a 48dcoe or 48 dhla from someone who had it tuned for a rotary. mazdadragracing.com sells the dcoe, but from what i've heard lately their service isn't exactly up to snuff......

I think the dual 40 dcoe's has more power potential than a single 48 IDA downdraft. 4x32mm chokes = 128mm. 2x42mm chokes = 84mm.

David G., you have the dual 40 dcoe's on a 12a j-bridge? If so I'd really like to know what the jetting is as I'm thinking of going this route with my soon to be built 12a j-bridge.

Who built your motor? How much $ if you don't mind me asking?

PM if you wish but I'd really like to know!
Thanks,
Brad

 

Your math is kinda funny...

32mm chokes have a ( pi(16^2) ) 804 sq. mm area, times 4 chokes is 3217 sq. mm.

42mm chokes have a ( pi(21^2) ) 1385 sq. mm area, times 2 chokes is 2771 sq. mm.

However you also have to figure that a single venturi will flow better than two venturis of the same area... something about boundary layers and air friction and all that good crap. But basically it works out that the twin 40's will flow a little better than a single 48 and they'll have better driveabilty because the chokes are small in proportion to the throttles (80% for the 40/32 vs. 87.5% for the 48/42).

That said, you need twice as many of everything to get them set up right. But man, once set up....

edit: Just went to Atkins' site... they do not have the Lake Cities manifold, they have the wraparound style (forgot name) that you can also get from Mazdatrix for less money. The Lake Cities puts the carb facing the other way - consider it to be a 1-carb version of the TWM setup. I'm kinda on a low-level hunt for a Lake Cities manifold - they look easier to port

 

Yeah peejay, that's what I said!

Thanks for more math.

Last i checked Atkins had that manifold for $250.00. Just email them. They bought the patent on it. Although they don't list it separately on their website like the wrap around, they have a pic of it in their f/i kit.

Brad

 

Most used setups go for around $800. I remember a guy on theparttrader a while back that had 4 or 5 setups with all the different manifolds. $850 or so for any combination you needed and they were all fresh rebuilds, I still have his number if you want to call and see if he still has any left.

 

Is the dual DCOE setup staged or simultaneous? ie. does it place one carb on the primaries and one on the secondaries or are they side by side?

And mperformance, if you guys are paying $300 for IDA manifolds then you are getting ripped off! I got mine for $100 AUD. (about 50 bucks American) In fact it would probably be cheaper to order one from here.

 

Nimrod, what do you mean by "all the different manifolds." There is only one style of IDA manifold as far as I know... unless you mean 12A and 13B.

 

Dual DCOE's are not staged or progressive. When you move the throttle all four butterflies move at the same time. Classical dual weber sidedrafts.

Brad

 

The carbs are side by side.

 

Cool. The reason I asked is because you can actually get a staged setup. The one I saw had dual 45 DCOE's on a 13B bridge-port in an Rx-3. It absolutely hammered.

It had the similar curved manifold but the carbs sat on top of each other above the engine. Looked great.

 

12A, 13B, 4 and 6-port if I remember correctly.

 

Yeah of course, that's right... my mistake.

 

mazdatrix has an entire setup for 800 bucks that i hear is damn good.

 

everyone...

Gamble302 Nope the mazdatrix setup is for stock ported engines. And it uses a U shaped manifold, a bit (actually alot) more restrictive.

Drivefast7 the webers are coming off a CRX yes...but they are going on a streetport 12A. The webers are webers and tunning is not going to be any harder than tunning any other setup, just got to tune both at the same time. I plan to tune it myself (i'm not afraid) YES it's possible. That's if I do get the TWM intake.

Peejay's theory is right on track from what I read on other sites. The dual 40 flow about 15% more and increase drivability in low rpms. It's actually the best setup for the street from what I'm gathering. Peejay they do sell the intake at atkins...just look under intakes and you will see the fuel injection setups and then the carb setup and you'll see in the picture the lake cities intake. You can purchase it separately or with the carb. (I think) Just like driveFast7 mentioned.

REVHED do they still sell 48IDAs down under? where can I get a hold of the $50 IDA intake? did you mean new or used? Let me know if there is a store selling a complete setup , intake and carb...I'm interested. If you can point me into a 48IDA/intake combo for less than $800USD I'll buy it.

NIMROD yeap I'm interested in the partraders guy selling the rebuilt setups, but can you just gimme his email.

 

http://community.webshots.com/photo/...4909PxAWMRtXDo

http://community.webshots.com/photo/...4882hUCjhkOQoi

mperformance keep us informed on how it goes. real life experience with drivability, power, throttle response, and tunability would be great to hear and is much better info than the theorizing we've done here. i hope it really works out well because I'm thinking of going that route too. not as much for the increase in power, but because Top End Performance said it'll have MUCH better throttle response.

 

yeap drivefast 7 I was going to post the same pictures. Thanks...

So far if I don't get a sweet used system I will get the TWM and go for broke. I will let you guys know for sure if I do get the TWM.

Hey nimrodTT got any pics of your personal setup? I emailed the partrader's guy and also I pm'd someone in the forum for his dual 36DCD setup. Hopefully something good will come out of this. Thanks again...

 

No prob. They're on my community webshots page afterall.....

 

im gonna put pics of the 36dcd and the twm intake on my imagestaion page. ill link it here asap. With my past experiance heres my 2 cents. for best "drivableity" i like the 36dcd, its a progressive opening . its GREAT off the line especial compared to my dellorto48. the 48 would kinda studder and then go.... just way to much fuel at a low rpm, the dcd is much better

 

On the car


Apart

 

REVHED do they still sell 48IDAs down under? where can I get a hold of the $50 IDA intake? did you mean new or used? Let me know if there is a store selling a complete setup , intake and carb...I'm interested. If you can point me into a 48IDA/intake combo for less than $800USD I'll buy it.

mp
if u still want a 48IDA with manifold, let me know and i will call this dude where i bought my 2nd set from.

mel

 

if going with a dual dco setup, how much more restrictive would a u shaped manifold be , rather than the twm one that leaves the carbs right next to the ports?