AGreen

iTrader: (11)

Because, like evil said, there are alot of really good carb tuners, who know nothing of EFI. You hear things like "I ripped all that FI **** out and put on a holley 850" as he spits his chewin' tobacco.

"Venturis are restrictive by design" is probably one of the best arguments, but think about this: How many parameters can you take into consideration for carburetors? Carburetors are a set-and-go type of thing. With fuel injection, it's constantly monitoring all sorts of parameters like temperature, throttle position, pressure, oxygen in the exhaust, air density, KNOCK, etc. Can a carburetor change fuel delivery or spark when the engine starts to knock? No. You just have to tune it stupid rich, change spark plugs every 1000 miles, and re-tune the carburetor every time you fill up.

dcolon02

Thanks for the feedback guys. I can see both parts. I appreciate the diagrams that was very helpful. I am new to the rotary scene and have learned a lot in such a short time because of you all.

Aaron Cake

iTrader: (1)

Ha! That exact guy came by my shop on the weekend. He had a first gen and ripped out the rotary to put in a carb'ed cast iron V8 and 4 speed slushbox. Because, you know, "those rotary motors only last 10K before they blow up".

Evil Aviator

I'm curious.... did he happen to say why he went through all that trouble as opposed to simply buying a Mustang, Camaro, or other perfectly good V8 sports car in the same price range?

Marshessn

iTrader: (-1)

Its a whole lot easier for some slower people to adjust carbs, than to implement and program computers.

Brain vs Brawn, brain will always win.

use your brain.

Aaron Cake

iTrader: (1)

No, I didn't think to ask that question. I had a feeling the guy was a few apexes short of a rotor. To give you an idea of the level of his intelligence, he talked about a white and blue RX-7 that flipped at Bonneville that he had read about in a catalog. Yet disagreed that he was reading either the Mazdatrix or RB catalog. So I'm betting the V8 and slushbox are some POS sitting in the corner of his garage, originally used in some kind of van or truck. It's likely going to be a hacked up installation with poorly welded mounts made of scrap metal, wires dangling everywhere, universal bendy radiator hoses, etc.

Now of course I have no problem if someone wants to do a proper V8 conversion. Which means an engine designed in this century, EFI, etc.

dcolon02

So now this thread went to a V8 conversation...LOL..

j9fd3s

iTrader: (3)

if you go road racing, the only "monsters" you will see with a carb are the ones where the rules say you HAVE to have one.

unless you're at a vintage race or something

j9fd3s

iTrader: (3)

the carb might be cheaper, but you have to buy jets and fuel pumps and regulators and all that stuff.

g14novak

iTrader: (1)

This question comes up every 2 or 3 months in the 2nd gen section...

Yes, it IS possible for carb to make more power mainly off the fact that the intake manifold runners are physically LARGER than a lot of the EFI manifolds (not all, but a lot). Therefor, making better flow. Most of the time its the manifolds restricting flow causing EFI cars not to make as much power.

I've driven a carb'd 2nd gen for about a year now. Same carb and manifold, been through 2 used motors. Before that, I had a S4 turbo swapped vert that dropped a seal and I junked (I was 17 and very stupid at the time). Straight line? My N/A might be able to hold onto the bumper of the vert. Going into some twisties? Forget it, all it does is bog.

Has anyone ever looked at any of the setups of high HP cars? It all depends on the application. I'm sure most people here have driven a carb'd car. Ever notice when you go around a corner and give it gas, it'll bog? This is the big down side to carb. The floats.

The conclusion being? It depends on the application.

Road race, auto-x, drift, etc.? EFI is the way to go. Smooth entry and exit of a turn is what makes good lap times and the judges happy.

Drag racing on the other hand is where the carb shines. For being a 20 year old "technically" outdated device, it works pretty damn good. It must if theirs still a large part of the drag community choosing it over something thats electronically controlled to give "flawless" performance.

Unfortunately, your right. My tuner here in Florida will tell you that fuel injection was a mistake. All his carb parts are stacked nicely on shelves and the old efi parts are left out in the rain. But different people specialize in different things. He can make a 1st gen run down the 1/4 in the 12s with the A/C blowing. From my personal experience, it takes a decent turbo car to do the same.

Evil Aviator

$960 Racing Beat Holley Kit (Carb, manifold, air filter assembly, etc.)
$175 Mallory 4070M Fuel Pump
$105 Mallory 4309 Fuel Pressure Regulator
$4 Fram G12 Fuel Filter
$19 Holley Choke Control Cable
$15 In-Car Mounting Bracket for Choke Cable
$50 Jet Assortment Kit
$16 Holley Small Parts Kit
$1,344 Total (Not including shipping)

wrankin

Formula 1? American LeMans Series? World Rally? Rolex Sportscar Series? Indy Car?

Carbs are simpler, and in a single purpose race car can allow you to reduce weight. As was pointed out earlier, in some race series you are given a weight advantage when running carbs rather than EFI. When used in conjunction with a dizzy, you can eliminate almost the entire electrical system, including the alternator. Also, with a race car you tend to primarily tune to one throttle setting - WOT, as well as a limited RPM range. Partial throttle and lower rev response are not as important.

But then you have the problems of tuning the carb for sea level and then taking it for a ride in the mountains. Or in the dead of winter. EFI can adjust better to changing environments than carbs. Less important for a race car, much more important for a street car.

-bill

Texrx

$500 for a good Dellorto sidedraft w/ 52mm velocity stacks
$250 for a Pierce intake manny
$50 for a Carter pump
$60 for a Holley FPR
$50 for a jet assortment ( I don't have and haven't needed, but I'll go along with cuz I should have)
$35 for a CB performance air filter housing
Stock '83 choke setup (it even kicks off once warmup is done and I only used it like three times in as many years)
$945 including shipping.

Pretty cheap compared to an equivalent FI upgrade, and simple as hell. Easy to tune if you follow the advice of a few guys in the FB section and only minor adjustments (no rejetting) twice a year. I am now on my second set of plugs but only because the old ones were old not bad.

All in all I love my carb! It gives great performance year after year and is less trouble than most of the FI setups I have had. For someone who has a sports car for fun or amateur racing it's a great setup. I used mine as a dd for 2 years without issue. And I drove the hell out of it!

Not to say FI is not better just that they both have their points. A well thought out FI setup will render years of trouble free driving and generally better economy but is much more expensive to build and tune. Stock setups are ok as well but with the age of most Rx-7's they will need attention and that can be frustrating and expensive for someone with little experience.

I would say it depends on your application. If you want cheap, simple, reliable performance buy a reputable carb setup, do a little reading, and enjoy. If you want a good, cheap, DD setup for "spirited driving" on the weekends, save your money and spend it on an FSM for your car and tune up for your stock injection. If you have deep enough pockets and want a performance machine that will operate at any altitude in any climate, go aftermarket FI, but get ready to do a lot of homework.