Me too. But, I've got this big, nasty (and very expensive) Weber 51IDA already, so no money for a Haltech. So I'll just have to go sacrifice a chicken, wish upon a star, or click my heels together 3 times or whatever Voodoo it takes to make a Carb behave it's self...

 

*taps toe and arms crossed*

You told me that if *I* wanted it to stay carbed I'd have to learn how to deal with them. And that's exactly what I did. Bought myself a weber book and talked to the old guys who would put a weber on a lawnmower. Just let me at it and I'll do what I can to get it working right! I've already got a few ideas.

 

Sooo... I'll just make my self comfortable on the couch tonight...

 

Hahaha you two are awesome!

 

Wasn't that your explanation of a rotary to the Datsun guys?

Rotaries don't run on fuel and spark. They run on black magic and voodoo.

If this is the case, that gorgeous ginormo-carb is the perfect match.

 

It's not the size that counts it's how you tune it

And it sounds to me like this gal's gonna give you a good schoolin' on how to tune it right

Jon

 

Haha, don't worry Dave, you know i'll be there to help when you decide to ditch the Carb and go EFI... *ducks as Jen takes a swing* j/k

Just kneel down and say a good prayer to the rotary gods... that's all it takes!!!

P.S. Not bad numbers based on where the current carb is limiting it... can't wait to see it at 10,000!!!

 

Good job Joe...!! sounds good; i think its time for some foggers............come on ,is the motor pinned? is so 250 will wake it up quick!!!!! ill call you 2moro..

 

I suppose we could always "borrow" your Megasquirt for some "testing......"

 

*raises eyebrow*

Don't you two start this when he's over next weekend!

 

holy joe what kinda cams you put in that thing lol j/k! motor sounds sic. that car sounds like its got a worse idle than mine lol but its got a reason lol. good job!

 

VE [( Displacement x Maximum RPMs ) / 1728] + 15% = Carb Size

^this might help!

 

I was looking through all my dyno runs with my Bridgeport and Holley carb, at 7500rpm we were making just north of 200hp and at 229 at 9200rpm. Those were our best numbers. When we went to the Weber set-up the car ran much better through the rpm range, however only made 217hp at the max. After that we started to use a Mustang dyno so we dropped 20%. I would like to run my peripheral port on a Dyno-jet just so I could get a good comparion to the Bridgeport on the power difference. We ran a max of 266hp on the Mustang Dyno, so it should be about 300 or so on a Dyno-Jet. PS I still have the Holley set ready to go if someone wants it.........................

 

Just a side note Joe, we found the 51 Weber to way too big for a bridgeport. Even when we put 40mm chokes in, it was still too much air/fuel. If you can find a 48 Weber I bet you will get it to run a whole lot better. If you want to try the Holley set up let me know.

 

I have some 46mm chokes here at home for it. There are 48mm chokes in there now, as per the recommendation of Nick at Rotary Reliability for a good sized bridgeport. We'll play around with it when it comes to its new home next week. If I need to order more carb parts (like I already ordered some jets), then I will.

 

We dont run 46 chokes in our peripheral port! There are 3 of us running peripheral ports here and we are all running 44's. When we run Shannonville we run 42's. We were told the same thing by others except Mazdatrix and we were drowning it. Just some advise from someone who has been there! lol

 

Strange, the 46's are what came with it from Racing Beat. I may have to look into something smaller then.

 

We went through the exact same thing when we bought the 51 for my bridgeport. I even called them to ask why they use 46mm chokes, but all I got was "in our testing thats what we used". When I went to some of the local guys who had been running Webers for years and my engine builder/tuner set us down the right path. I would say for your bridge even a "monster bridge a 48 weber or a 51 "choked down" to a 48 would work best. We had machined some 38mm chokes to test on our bridge but build the peripheral port before we ever got to use them. I would bet if you used 40-42mm chokes you would get better results. By looking at the dyno chart I would guess your ignition cant fire the fuel/air mix going in.

 

What seemed to happen right when the carb fell on its face, was fuel vapors would form like a mist just above the veolicity stack, then BOOGGG, just stopped revving.
I forget what Glen at Forrest and Forrest told me, but he's seen it happen before on different engines.

 

Whats the air velocity through the stack?

 

The thing that baffles me, is our current bridge-ported engine (while it didn't make a lot of power, thus this new engine) would rev smoothly and pulled fine until 8000rpm plus. We took that carb off the car, didn't change a thing, put it in a box and bolted it on this one. This new engine should, in theory, flow better than the old one, so I don't know why the carb would be too big now. Very weird.
But thanks 01, I think you may have started down the right path to sorting it out.

Just need to get it in the car, get it broken in, and start tuning.

 

I think with less fuel and air you should have pulled clean to over 10,000. I used to shift my bridge at 9-9500 and would rev past 10 if i had to. We made our max power between 92-9400 on the dyno.

 

You may be on to something there. A good place to start anyway.

I never tried to run the old motor much past 8000rpm because it wasn't built for it.

 

Hey, I am not even going to get into the carb tuning thing, but if it was me I would listen to Al. He has a ton of experience working with the Webers on a BP, a JP and now a PP. I think the chokes are way too large as well. Racing Beat must have a ton of 46 and 48 mm chokes in the warehouse.

What I wanted to let you guys know was how hard Joe/RPM works for his customers.

I had promised an extra NA box to Redshift for a spare. Joe and I have worked out about 5 times for me to bring it to his shop to get packaged up to send with the motor. I have been extremely busy with work issues and have had to break each scheduled drop off time. Joe was concerned enough for his out of province customer that he drove to my house today (about 1 hour 1 way) walked out into my snowy and muddy backyard and pulled and carried a box out of my collapsed 1 car tent storage garage. By the way those portable garages don't like wind and heavy wet snow, ask me how I know.

When he was building my race motor he arranged for some good S5 rotors for me at a great price. He even went and picked them up for me. I know now it wasn't just special for me that he did this, it is how RPM treats their customers.

RPM gets it.

Eric Nummelin

 

Wow. I had no idea Joe would do all of that. I was talking to Dan last night and he mentioned Joe was in TO and coming back with the transmission, but I figured he was going to TO anyway and was just picking it up on his way by. I was a happy customer before, but I'm really impressed now. Guess I'll have to make the RPM logos on the car even bigger now.

Thanks a ton Joe, and thanks a ton to you as well Eric. I certainly owe you a debt for the transmission as well. Both of you.
Not sure what I can do, but I'm really grateful to you both.

As for the carb tuning, it's all voodoo to me, so I'm certainly going to try everything that 01 recommended. I'm open to anything, especially people who have tried them and with the same carb.
Real-world experience beats "what the book says" every time.
I just need to scrape a few $ together to get a selection of smaller chokes.
(Although, as for the 48s, those were recommended by Rotary Racing and Reliability, who are even listed in some of the Weber manuals and considered a Weber authority. These huge chokes must be a California thing. Typical.)