Let me help you. The RB 12A and 13B carbs are both Holleys so it is relevant as I owned both of them and I did the Mod to the 13B carb. It is also applicable applicable to the 12A carb, the only difference is size.

 

Many of us forgot more than you will ever know.

You are a kid.

 

In what world is a 49 year old SSGT a kid?

 

In your attitude, mentality, and demeanor.... In this world

 

My world.

 

Whats that on my boot? Pissed off ricers again?

This thread was about a guy looking for a "cheap" holley-based carb for auto-x.

I happen to have a wealth of knowledge and experience in that venue. I *tried* to warn the OP and all possible future readers about making the mistake of ruining their car with one of those zinc casted relics.

It pisses people off when they have to think outside their comfort zone and do something more creative than what they were convinced would be the best solution by some salesman or misinformation.

You coming in here with absolutely no regard to the topic on a street application 13b that was years before the quality of anything built by racing beat currently (good or bad) had nothing to do with what was being discussed. It was just a positive story to a shitty product!

I have raced Holley and other competitive modular based carbs for close to 10 years on domestic AND foreign cars to include our Rx-7's. In comparison to virtually any other carb they are subpar at best. Not real performers in any department.

On the street, the horsepower even compared to stock is very small, for the cost of a custom fuel system and craptastic part throttle response and gas mileage.

On the strip, the added horsepower over stock lowers ET's but tends to lean out the front rotor because under acceleration the front jet and metering well are robbed of contact from the fuel sloshing to the back of the bowl. So it makes R2 richer than ideal, and can lean rotor 1 to dangerous levels. It also only lowers most 12a cars to the low 15 and sub 14 second ET's, so what is the point?

On the autocross course the holley carb isnt good for ANY application in its standard form. Its fuel level control is **** even when mounted and used the way it was intended, let alone our gimped version. These things negatively affect engine tune in almost any common condition one would see on a technical course. Lean, rich, flooding, starving, etc. The harder you push the car for lap times, the more the carb struggles to adequately use the calibration that we work so hard for our engines in the first place.

My "attitude" towards this topic is a direct reflection of the time/money I have wasted to build the damned things for people and myself in the last decade. Im tired of Ricer fans of RB or even Holley stepping in to defend what is possibly the worst product to sit on the shelves of any speed shop with the words "performance" on its packaging. They are a waste of money, and a waste of time.

You can re-invent the wheel like some of the other posters here and stake the claim that you can build a good one, but odds are you have no idea how a proper running engine should act with a carb sitting on it in the first place! Hence why so many come here (to me) for advice on these things. Its only after I tell them what they dont want to hear that I am a dumbass who knows nothing. Which are you?

So if you want to spend 1300$ on an RB set-up that they offer almost zero tuning advice for, that pretty well sucks at anything you'd want a sportscar to do, be my ******* guest. ricers

 

You probably know what you're saying but no one cares because you come across as a dick. Being in the military you should know this term, RESPECT, it's one of our values.. Try it out. Here's another one, tact....

 

Sorry if I hurt anyone's feelings.

 

Listen Sport,
The thread wasn't about "cheap" holley-based carb for auto-x" it was about getting a Holley and two different sets of jets, one for daily driving and the other for track so I'd say your reading comprehension is lacking.

As far as me I have been building and racing RX-7's for over 35 years not 10, you are a damn neophyte. I have driven almost 500,000 in FB's. I have built engines from SCCA, IMSA, formula Mazda's and on and on. I have worked, tested and dynoed just about every intake system ever devised for the FB from RB, to multiple Rotary Engineering systems to Holley's to Webbers to Tr-Cities to stock modified carbs and on and on. As far as not knowing RB products I know the owner of RB and have for almost 30 years. (Jim Mederer)

What I offered was a tip to stop jet clogging in carb induction systems that inject oil before the manifold, it will work on any carb.

As far as tuning advice from RB for their re-jetted Holley what do you need? It's plug and play. If you want to experiment buy a couple jets and do so, throw the car on a dyno, it's a basic Holley not a million dollar slide injection system.

What RB does to their Holley's is no secret, you can buy a Holley and copy what RB does. The Holley works excellent on the RX's, we saw ~210-220 WHP on ported motors. The Holley is trouble free and you can buy parts at the local auto parts store on a weekend. That's what is so nice about it.

Secondly, more HP doesn't lower ET's, that's laughable and leaning out a N/A rotary isn't dangerous you aren't going to pop a seal or break anything especially in a 1/4, it just runs lousy. The rear rotor also doesn't run richer, because of fuel slosh it either has a constant flow or doesn't under WOT. We saw mid ~13's out of street ported 13b daily drivers with ported motors and bolt-ons and Holley's. We got 12A cars into the high 13's to low 14's with the same set ups but also running a 4:44. Are they great for auto crossers? They do OK but he isn't trying win the Nationals.

The OP asked a simple question and others here have responded but you decided to attack them instead of offering advice. I'd also suggest you better know what you are talking about before attacking others and making ignorant assumptions.

 

I feel like I have friends again.

There is some great info for anyone who want to read my posts.
Regardless of what anyone else might assume about holleys and rotaries I have one on my car right now running strong.

Someone might say my tune is flawed but my good power, mpgs, passing of delaware emmisions and zeitronix wideband data logger say my tune is just fine.

If you read through my posts there some good setup tips on how I did this and anyone who wants to contact me feel free to post or pm a question.

 

Funny, Jim Mederer personally built and assisted in the tuning (in person, at the dyno) of one of my own 465's, and after almost 3k$ worth of parts, shipping, travel, and dyno time I had a 117 RWHP, 16 MPG piece of **** to show for it. The fact that I went out there to prove to them that not only the 2 that they sent me initially were junk, but that the carbs themselves were **** too. And that was on a dyno mule 12A. With around 20 hours of use on it.

Jim himself, after 3 days of messing around with this thing finally admitted that the Holley carb was "not a quality carb" and "not ideal" for the rotary engine. He also commented that the later Holley castings had not been dyno tested until I came around in the first place, so they "weren't aware" of changes to the carb metering blocks and main bodies that they hack up for fuel signal.

Having said that, he also commented that they should probably look into changes in calibration for modern gas, as well as the many changes to the late model holley 465 casting; but the last time I spoke with him no changes were planned for them at all, so I literally wasted all that time and money to go out there for nothing at all.

And that was BEFORE I started building my own in 2009, only to come up with a REAL solution to their performance let-downs in 2013...Replacement.

 

I built several of these for customers of AED in the northeast over the years, and using expense as an imaginary factor, COULD build "proper" 4150 based carbs based on real standards, not shade tree baselines.

And if I seem rude to morons who do sit here and puke out misinformation about the subject, it's because of all the carbs that were actually built to beat lap times, and all the ones destined for REAL track cars, none of the half assed, shade-tree tuning logic found in this thread was used at all... Just simple booster and circuit calibration. No cutting, hacking, drilling, or any of that racket. I have offered good advice on this forum (especially this topic) that goes ignored time and time again. I feel a loss for the owner every time I get a PM or email or phone call to set one of those pieces of **** straight. At this point I really dont give a F*ck what you waste your time and money on, so long as I told you so from the start.

Running rotor 1 lean at top end is dangerous, I have at least 2 engines in the shop right now with loss of compression on rotor 1, from warped and sticking apex seals and god knows what else until I tear them down. Both Holley cars...coincidence? Don't think so.

And to be clear, this thread WAS about a "cheap" holley for a 12A with "different sets of jets" to swap out for either application. Question, doubt me, or slander me all you like; I'm right in the end.

 

[QUOTE=wankel=awesome;11723169]I built several of these for customers of AED in the northeast over the years, and using expense as an imaginary factor, COULD build "proper" 4150 based carbs based on real standards, not shade tree baselines.

And if I seem rude to morons who do sit here and puke out misinformation about the subject, it's because of all the carbs that were actually built to beat lap times, and all the ones destined for REAL track cars, none of the half assed, shade-tree tuning logic found in this thread was used at all... Just simple booster and circuit calibration. No cutting, hacking, drilling, or any of that racket.


You stupid stupid stupid JERK!

No cutting hacking or drilling to tune your 13second nitrous bridge port piece of junk. We have gone 12.0 in a bridge port starlet holley carbed and 10 seconds with nitrous. You are a f*%7ing loser.

You can not build a holley for the street without cutting the trans slot. What don't you get! If you idle you holley and the trans slot is not visible below the throttle blade it will lean out as soon as the trans slot is reaching vacuum.
That leaves you with 2 options
1. cutting the trans slot
2. leaving the idle ridiculously Hi for the street.

READ ANY HOLLEY TUNING BOOK THE TRANS SLOT MUST BE VISIBLE AT IDLE. Extending the trans slot is the exact opposite of drilling a hole in the throttle blade to stay in position with the trans slot on a cammed v8. As drilling a hole will work for a large cammed v8 setting a 900rpm idle for a rotary and then extending the trans slot is what works on are cars.

This is not a hack job and tuning the emulsion circuit is not necessary for pump gas as holley has done a good job of this for you.

The upgrades to my carb are simple.

1. 9776 450cfm
pink cam shaved. Adjusting the spring like you said hurts low end throttle response because the spring is too soft and compresses instead of shooting fuel.
2. 28 shooter
3.double step boosters. yes I have the tool to press them in it was $300
4.extended trans slot necessary for smooth low idle.
5. idle air bleeds that give you some controll over the low end air fuel ratio before the main booster kicks in.
6. jet extensions something you really need to learn about if you are having trouble on the interstate turn ramps. LOL
7. secondary metering block , can't rejet a stock metering plate.

You are major loser and I feel very bad for anybody you have done carb work for.
You have failed where I have succeeded, You are a major chode!!!!

YOU SHOULD BE HAPPY THERE ARE PEOPLE LIKE ME WHO CAN HELP YOU.

 

Pink cam has to be in #3 position

First you set the idle then you extend the trans slot to where it should be according to any holley tuning book.
Wankel=awesome this is what you are calling a hack job by some shade tree moron LOL. No wonder you don't like holley, you simply don't know what your doing.

 

Wankel=awesome I'm not surprised to hear u say you have 2 rotary engines in your shop with blown apex seal after being driving with a holley carb tuned by you. Don't blame holley for your mistakes.

 

I didnt build either of those carbs, they are off-the-shelf RB carbs. And my 13 sec 12A car was a half bridge, with an hp390 holley. And a "mild shot" of NOS was a 50 shot. That was on a full interior '80 LS with 13" toyo street tires and stock gearing. Cool thing about that car, was it did 13's all day that way and still got 22 MPG. It was just very darty and very rough on decel because it wasnt tuned for street driving, it was tuned for enrichment above 4k RPM for the NOS shot...

Show me another half bridge 12A running that small a carb on shitty street tires clicking off 13's with a 50 shot, please.

And as for the trans slot thing, would it blow your mind if I told you that AED's for use on sealed 900+ hp V8's have that same .20 trans slot as a stock holley? Would it blow your mind that NASCAR are using .20 trans slots? Why would a 120 hp (maybe) rotary engine want anything bigger than whats already there? And yes, I would say that those books your're reading are telling you the wrong way of providing fuel to that circuit. See, engines dont care about the total amount of fuel they are receiving through that slot. It is there for transition, idle, cruise, decel, or any other closed to low throttle position. If your engine is running lean you can do: A) Add fuel to it which could reduce throttle response and greatly hurt MPG's for normal driving, or you can: B) Reduce the amount of air in that circuit to achieve the desired ratio of air/fuel you need for that transition.

By cutting the slot you just make it a free-er flowing circuit, which is actually bad for everything in the long run. Thats like me drilling your nose for bigger nostril sizes because you can't run and get enough air to your lungs through them to sprint. The way to fix it right, would be for you to open your mouth, get your air from elsewhere (another circuit), and to reduce the amount of air you need for that sprint in the first place.

Your carb is doing the same thing, but if it really needs that much more fuel at low throttle conditions it needs to get the fuel from somewhere else, namely the booster or enrichment circuits. You can just calibrate the circuit to have less air in it in the first place, trumping your lean condition and not adding more fuel to reduce efficiency across the board.

Hope that makes sense, but I really could care less if agree with it or not. Fact is, the OEM built carbs for something like 40 years using .20 trans slots on a plethora of different applications ranging from 4 cyl, all the way to screaming Nascar engines. Holley and Motorcraft Modular series carbs that is.

 

[QUOTE=wankel=awesome;11723862]

And as for the trans slot thing, would it blow your mind if I told you that AED's for use on sealed 900+ hp V8's have that same .20 trans slot as a stock holley? Would it blow your mind that NASCAR are using .20 trans slots? Why would a 120 hp (maybe) rotary engine want anything bigger than whats already there?


Why would a 120 hp (maybe) rotary engine want anything bigger than whats already there? It's simple. the rotary needs the longer trans slot because if you want a 900rpm idle on a rotary you have to lower the throttle blades to the point the trans slot is completely covered. If you set the idle and go for a drive the car will go very lean when the slot is uncovered. Even with my programmable ignition I can only take so much timing out to lower the idle. Like I said you can either keep the throttle blade in relationship to the stock trans slot and deal with the high idle or extend the trans slot and lower the idle to something normal. i never changed what the trans slot does, I didn't do this to add fuel, I just extended it to where it needs to be for a 900rpm idle. Keep in mind I'm referring to a stock holley not a RB. Changing the air bleeds will keep the A/F ratio stable until the main booster kicks in.

 

 

 

 

 

What a liar you are. Jim hasn't participated and wouldn't participate in dyno tuning a silly 12 A Holley project for a 30 year old car, he doesn't have the time, interest and he doesn't care. I'm sure you wouldn't mind telling me when and were this happened would you? You also made another whopper, an N/A rotary is basically impervious to changes in gasoline or octane. The RB race car ran of 87 octane, you can **** in the tank and they run just fine.

What an absolute joke.

You also lied about the dyno testing. Racing Beat dyno tested them on both the 12a and 13b's in the eighties. Plenty of us throughout the years have tested them as well. The fact you claim 117 rwhp is also a joke, what else was done to the car? This should be good.

We ran them and used them for years and they worked fantastic. The fact you can't get an out of the box Holley from RB which is a proven carb to run tells me how inept and how little you know. I knew this when you stated lean running and dangerous on a rotor. Laughable.

 

RB sets up their carbs to run very rich so you don't have a clue what you are talking about. Secondly a seal won't stick "on the top end" from running lean you dolt. I ran my car EVERYDAY to 10,000 rpm plus on a RB Holley, out of the box. I'd get 120,000 plus miles on every rebuild.

Keep showing your ignorance, and how little you know I am getting a great laugh.

 

Jim was there, and It was to settle a year long dispute that RB had sent me a junk carb. One that wouldnt run on a stockport 12A because of massive lean conditions. They argued (RB) for over 7 months that it was the condition of my engine, so in a deal worked with the OTHER Jim (Tanner) we were to find a well running 12A car (customer of RB locally to Cali) to run my carb on. I didnt go for mailing my 650 dollar investment on my own coin to them to fix some issue that at that point I was sure was their mistake, so I offered to send the carb back only after I had received ANOTHER carb to replace it, which would settle if my engine or the carb was at fault. The chances of 2 of their carbs being fucked up, even I thought would be slim.

But after I had received a second carb with all of the same issues, I was willing to be shown how one performed on a "healthy engine". I took J.tanner up on his offer to test my carb (and the replacement they sent me) with a twist. I said I wanted to be there, since after the second carb was having issues I started looking into possible changes at the plant where these RB 465's were built by holley. RB was sure it wasnt their mistake, and I was sure I had a Mazda rebuilt 12A that ran perfectly with a Nikki on it.

I was right on my hunch that Holley was jetting the un-modified 465 differently than what they had 5-10 years prior at that time, and were even using totally different castings at that time as well as a "new" 2 restriction power valve circuit over the old 3 restriction. I took this information back to Jim M., who commented that he was unaware of those changes, and that bench testing the carbs they dont actually run them on an engine, they just do a thorough inspection of the mods made, and check for the correct orifice sizing etc. He said he would attend the dyno testing on the "customers car" which turned out to be a pettit dyno mule.

I flew out on May 19th 2009, just after leaving the Air Force as it was the first chance I had to travel. I paid my own hotel, and basically went on vacation in Cali for about 4 days. On day 2, the first of the RB carbs was set up on the dyno mule, and to everyones surprise it (except me) it ran like ****. The tuner present said it looked 10 jet sizes too lean (not rich like you already commented) to the point where it was lean surging and refused to smoothly transition on the primary circuit. Off idle the engine would even cut out and die occasionally. We watched as they removed the first carb to do a direct swap to the 2nd carb I was mailed, and it had similar issues, but interestingly enough was judged as only "8 sizes lean".

End the end, It was Jim M.'s call to bypass the power valve circuit (which they had always used on stockport carbs) and jet from a 49 to a 58. This solved most of the problems, but ran it so pig rich and gave it such shitty throttle response that it felt like the car was downgraded. Even after those changes, the carb I took home (being the better of the 2) only made 117 RWHP. And this car had RB headers, and the long primary exhaust installed.

After I got it home, I made many calls to RB (as I was directed to stay in touch with the results) about its day-to-day operation. I was averaging 16 MPG highway, and was lucky to get 100 miles to a full tank in the city, but I never averaged its MPG's because of the choked start-ups and long warm ups that that POS required to even make power off idle.

Jim M. commented to me that the changes Holley made to the PVC and low speed circuits for better fuel economy to the standard 465 was responsible for the lack of performance. He also said that thanks to my dyno time and 2 tested carbs, that the jetting and mods would change slightly to better suit the tune.

However, after buying yet ANOTHER in 2012 brand new from RB that had the SAME ISSUES, and went through the same damn problems with, I vowed to never do business with them again. The brand new RB 465 I bought in Oct, 2012 still sits on a shelf in my shop. I made a thread here about my experiences with it and virtually did what Jim did to fix it. Jet it way up, bypass power valve, and lived with its terrible performance for over a year of daily driving.

And it wasnt ME who suggested that changes in gas affected the carbs tune, it was RB when they were grasping for answers as to why they couldnt make carb 1 or carb 2 run on their delivered jetting.

And the videos posted above are irrelevant (again) because they are on a 13b, using a totally different carb (600 cfm, not the 465 casting in question).

 

[QUOTE=ghost1000;11724049]I agree with what you're saying on the extension for the trans slot here, but neither of my carbs or the ones I built 390-465 models ever had the throttle blades closed enough to cover the trans slots entirely. I just adjust the blades to the .20 slot exposed, and then use other means of tuning to lower the idle speed to the desired level. Which, contrary to popular belief is the right way to adjust it, not to play with the shiny screw that holley put there with the intent that it wouldnt be so oversized on an engine that it would need to shut the throttle blades that much.