I know this has been discussed on the forum in the past, but I wanted to get some more input from the old school rotorheads..

I am looking into upgrading my carb/intake, and so far am considering the Weber 48IDA and RB Holley 465 systems for the 12A in my RX-2. Now, currently the motor is a stock port with headers and open exhaust, but I do have future plans to either street/bridge port the 12A when the time comes.

Anyone have first-hand experience with both carb setups? I've read that max. HP output is nearly the same with both setups, but then some say the Holley is better on the low end and Weber is better @ WOT. Does the Weber have a quicker throttle response vs. the Holley? If anyone has a pros n' cons list they could rattle off that would be great.

For a mainly street driven (some occasional auto-x) car, which setup would you go with?

Thanks,
Mike

 

they both work great, its your preferance.. i like cheese

 

i only have experience with holley, both the 465 on stock port and 600 on sp. and mikuni for a very short time just to see what kind of difference there was. the holley will yield better fuel mileage and they're pretty much the same at WOT. either way, once u port the engine, u'll need to upgrade again. the 600 is too much for stock port and the 465 wont be enough for any kind of port over stock.

 

I was lucky enough on my FB to have a revolving-door of caburetors. Within 2 weeks, I ran a modded Nikki, 74 Hitachi, RB 465 Holley, RB 600 Holley, RB Dellorto, and now run a RB Weber 51. The Holley was simplest, though my lower face was warped, so it took a LOT of hylomar to seal my vacuum leak, later to have it machined (the 465). The Holley also ran the best day-to-day, but I never really liked it because it wasn't horsepower king and wasn't very different. The Nikki and Hitachi both ran fine but lagged behind the Holley. The Dellorto was king of day-to-day drivability and tunability, though it was a necessity. Dellorto jets can be changed with the car running and mine needed it. I made small changes every few months just to stay in the right main and air jets. Dellorto also had 4 progression holes and a choke, so it did GREAT (DHLA 48).

Then I got my Weber. It isn't as drivable and doesn't have a choke, but good god it can suck down the gas and feed anything. There's a reason why old Jags, Ferraris, Lambos and such used Webers. I like the Dellorto design better, but my Weber now has a much-extended float bowl, modified accel pump, and now also has 4 progression holes, so it's not so much an on/off switch. Plus, I want to cut a hole in my hood and poke the carb up, so the IDA works fine.

Go with Dell or Weber if you want something unique that either drives well or hauls ***. If you want to putt around and never touch it, get a 465 Holley. If you only have $15, go to the junkyard and get a Nikki.

And I've seen others say that a 465 won't keep up with a ported engine, but mine did fine on a extended 13B and kept picking up the power up to 7500 revs or so and would likely keep going. I didn't build that block, so I didn't take it past 7500.

 

I actually hated my Holley. Even properly set up with race bowls and weber powerplate, it still sucked. Don't think about turning left with any throttle....sputter....sputter.....sputter...got a 48IDA and love it. Wouldn't go back if you paid me....doesn't smell like gas all the time either.

 

another vote for weber

big down side - holleys like to wear after awhile and leak at the throttle shaft


the weber will breath alot better topend. Sound good running.

Depending on how far you port your motor you may need to extend the fuel bowl (only when u are under heavy acceleration for extended time - ie accelerating from start to max speed)


The 48 IDA's were used as race carbies for a good reason

 

Hmm, odd that RB would offer a street ported version of the Holley 465 if it wouldn't be enough. I wonder what all is done to the carb compared to the stock port version. They don't really specify how large of a street port it's meant for though.

Mike

 

Get the IDA since you have plans to get either a bridge or a streetport. If you go with bridge, you can modify the 48 IDA to a 51 for approximately $150-$200. WIth a holley, you will end up buying another carb. So as I always say, spend your hard earned cash wisely. IDA is one carb that will fit all with just a few mods such as re-jetting and changing venturies. Oh yeah, I have experience on both IDA and Holley. My holley is just sitting in the garage collecting dust and as a decoration.

 

If you are going to use the holley setup then make sure you get the center hung float bowls. The cornering effect is a bitch! Funny to watch someone try and do donuts without the center hung float bowls (chokes, sputters, backfires, etc.). Just ask kettleman.

 

Yes, I'm definitely leaning towards the IDA.. thanks for all the input on the pros and cons of each. Now if I can just find a nice one w/intake, etc. Anyone know of any for sale?

Thanks,
Mike

 

That has always been a big debate in old schoolers. Like someone above already stated they both work good,its all personal prefferance. Ive had dellortos and holley,i preffer holley,almost everyone in P.R use holleys on stock,street,and bridgeport.They go to IDA when they go PP. I preffer the holley to me its easier to tune and easier to get parts for it.And i like the way them 4 barrels sound when they open up WOOOOT....lol

 

Go Weber for sure! 45 doce or the 48IDA. My 45 on a large streetport 12a smoked a stock 93 twin up to 70 mph. That weber made that cae haul ***.
I was at or just above the 200 hp mark.

 

So what's a good/average price on a Weber setup (including intake).. & Holley?

Mike

 

I wont pay more than $600 including air cleaner and intake manifold.

 

45 vs 48 = the difference is like CA coast and FL coast during summer days.
CA wishing for some rain while FL wants sun.

 

Well, I went with the 48IDA.. should be getting it here sometime next week probably. My next question is, what fuel pump did you guys go with? This is going on my '73 RX-2, so I'm curious what pump people prefer and how they have it set up. I've had a Holley & Carter in the past and both those seemed fairly noisy, but maybe they're all like that.

Mike

 

don't know what brand but the majority probably use a 12 lb pump with a pressure regulator to bring it down to around 4-6 lbs. or maybe even a high flow pump.

 

Holley Red....Holley FPR, 5psi.
I thought it was loud when I got it but it either got quieter or I got used to it.
I also heard Carters are loud...Mallory's are pretty quiet. Just stay away from the Facet pumps....you'll run out of fuel at the top end.

 

Ah, thanks.. so did you still use the return feed line, and where did you mount the pump?

Mike

 

No return...pump is where that little panel in the left side of the trunk...made a plate held down by nutserts, most of the pump is below trunk level with 2.5" of the top of the pump in the trunk itself. Looks clean and easy for removal and inspection.

 

ah, thanks.. sounds nice. For some reason I was thinking the stock '2 pump was inside the tank.

Mike

 

No, stock pump and filter are under covers in the trunk. I'm planning to run supply and return lines for later EFI, but capping the return for the time being, just in case I go turbo later. Something to think about while you're messing with everything. It's already been said, but my Holley red is loud as hell, too. I'll try Mallory.

 

So Weber 48IDAs need about 5 lbs. of fuel pressure?

I've been looking into the Mallory pumps, and they seem to have a 7 & 12 lb. version. I'm wondering if the 7 lb. one would be enough once it reached the carb, or if going with the 12 and regulating down is the better choice. I know the Carter I installed before in a RX-7 was rated @ 7 lbs. but it was only 3.5 @ the carb with no regulator. Maybe I used too much rubber hose on that setup though.

Mike

 

At high flow, you'll have more than a 2 psi pressure drop (it takes pressure to drive flow, so it's necessary). It's usually 1-2 psi drop, and even though your float bowls might slowly start to drop, why risk it? You don't want it leaning out and knocking once your filter gets a little sediment or something else clogging it. Why cut it so close when the 12psi can be had just as readily?

Go with the 12, and let me know what it costs. I think that's what I'm gonna go with too.

 

Carter pumps came with 2 types: 5psi OR 7psi. I cant recommend Carter - got multiple bad experience with inconsistent fuel pressure. I just cant remember which one. Holley RED is good. If you're worried about the noise, no matter wihcih pump you use, it will be loud. ****, even the old 6psi FACET pumps were loud. Its easy to make it quiet. Buy a cheap beach sandals and use that as rubber spacer. The thicker the better. Mallory is good but costs more than the holley red. With the IDA, there are ways to modify them. If you're interested, PM me.