Was doing some research last week and stumbled on this- http://www.racingbeat.com/FRmazda2.htm

Im not a big fan of EFI for one reason.... Not being able to tune on the go "unless you have a computer, so thats why Ive been wanting to resort to a carb'd intake setup for awhile. I was going to purchase the intake mani and a holley 600 CFM Four Barrel Race Carb. I know im going to get flamed to hell because people have there opinions but i dont care really. I only want opinions from people that would like to add to this.

 

What is your question?

If you're looking for opinions on this setup, I'de check GSL-SE's on the 1st generation board. That's what I did. If you know carbs better then go ahead, just be prepared for the negatives as well as the positives.

 

Plugging in a laptop and key stroking over popping the hood open and haveing to get dirty/smelly and take **** apart over and over till its right? And thats in the summer, now here comes winter.. DAMNIT, now your jetting is too lean... dirty smelly work again, wait ****, did I just drop a nut into the manifold??

You get my point. I went carb'ed on my 2nd gen and although the gains are nice, the drivability SUCKS. The thing always seemed like it needed re-jetting and the car always smelled of fuel. Carbs cannot compensate for altitude changes or temperate. Fuel injection does all that and then some. You can lean the hell out of it in low loads for crips throttle response and fuel mileage, and then fatten it up for WOT (Wide Open Throttle). And the kicker is, your car already is equipt with it!

Another thing for consideration is the ignition system. Using the stock ignition system with a carb SUCKS (yes, I've tried). SO more money and time getting a dizzy and coils from an older model (again, older model, backwords progression).

And yet more stuff that will need attention.... your stock fuel pump is rated WAY too high for a carb. So that will need to be yanked and some sort of pick up system retro fitted. Now your going to have an annoying LOUD external pump. You'll need a new regulator as well (something in the 3 to 5 psi range I believe, its been a while).

You had no specific questions, and said you wanted to hear opinions.

 

what kind of mods are done to the engine anyway? big porting?

you can easily tune many aftermarket efi systems on teh go. ive done plenty of tuneing while cruising 60 mph down the freeway, stoped at a light adjusting my idle. my car starts cold and idles right away and never dies at a light when warming up.

for example i have used the apexi safc, which can allow changes to the fuel maps.
then i have also used the apexi power FC with comander, you can fully change your timing and fuel maps, temp compensation maps, rev limit, on the go, with a small hand held controllor.

 

heres a break down of a comparison in my opinion of what u could do if you have an engine with intake exhuast, and maybe even some port work done.

with what u want to do
holly intake kit + u need a fuel pump and regulator,+ different jets ect to tune.
CONS: only adjustable while stoped,tempurature/alt changes can effect tune,runs poorly when cold, harder to start.
costs:AT LEAST 960 dollars on the rb website.


use stock EFI,+ SAFC
PROS: still have factory o2 corection for gas milage,runs cold easily.
also you can tune this on the fly, its a small hand held device that u can adjust the fuel with by modifing the air flow meter readings.great for a na car with stock injectors.

with eather system u would still want to be tuning this with a wideband sensor anyway so i wont add that to the cost of eithe system.

 

jesus christ, carb may not be the best idea, but a holley is a terrible idea on a rotary IMHO... look at a weber in the least.

 

You can't fully tune a carb on the go because you would need to install various hard parts, such as jets, emulsion tubes, power valves, springs, etc. Since you don't want to carry around a laptop computer, then you probably don't want to carry around a box full of carb tuning parts and tools either. At minimum, you would at least need to pop the hood and get out of the car to make any adjustments on a carb.

If you truly want to tune on the fly without a laptop computer, then get a standalone EMS with a hand controller. This will let you tune from INSIDE the car with NO tools or hard part swaps. The added advantage is that the EMS can display tuning data, as well as datalogging if equipped, while carb tuning would require you to purchase these items separately and carry them around in your box of carb parts.
http://www.microtechefi.com/microtec...p?product_id=9
http://wolfems.cart.net.au/details/106561.html

I think you will find that once properly tuned, an EMS does not require constant tuning like a carb. Also, you will find that since nearly every EMS has an engine load parameter, there is no longer any such thing as an "economy tune" and "race tune", as in most cases they are combined on the same EMS map. Additionally, the EMS can be set to compensate for changes in air temp, air pressure (altitude changes), water temp, battery voltage, etc. Therefore, your "tune on the go" preference is pretty much a non-issue with an EMS until the engine wears down enough to require minor retuning.

Honestly, nowadays carbs are only good for race events which ban or penalize EFI, or for engines that need to run without an electrical system.

If you still insist on downgrading to a carb, here is Racing Beat's recommendation chart. Keep in mind that it assumes a header and racing exhaust. Don't forget to install a low-pressure fuel pump and regulator.
http://wwww.racingbeat.com/PDF/intakeguide.pdf

 

Wow, its clear most of you have never worked with carb'd rotaries...

I ran a Holley 660 on my FC for about a year. The car ran great, started first crank every morning even during winter (even though it only gets down to 30's-40's at its coldest here). Honestly, it use to start faster than any EFI FC I've ever seen(see my vid posted below). Never had the choke hooked up. The car ran great. The only problem I had with the car was city mileage sucked. Highway couldn't be better. When it floods, you don't need to mess with a bunch of fuses under the hood, you just hold the gas to the floor (similar to S5) till you hear it start to fire, then let off.

I don't know what bs your talking about messing with jetting when the temp changes. Only change I've EVER had to touch on my carb was the idle in the year and a half I drove it like that.

On top of everything, EFI cars feel like they have no *****. If your complaining about drivability, you probably shouldn't even own a 7.

If you want to try carb, go for it. Just know, your city mileage is going to suck. And it runs a little funny while its still warming up. Besides that, I think you'll be a ton happier with it carbed. I saved my self so many headaches with not having to mess with vacuum problems, grounding problems, leaky injector problems, etc.
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<embed width="600" height="361" type="application/x-shockwave-flash" allowFullscreen="true" allowNetworking="all" wmode="transparent" src="http://static.photobucket.com/player.swf?file=http://vidmg.photobucket.com/albums/v112/Xenium911/07-28-09_1829.flv">

 

Here's a cheaper intake ($209) JW you can order it from Summit. I wanted to try this one on my next project. I ran a holley on my camden supercharger and it was fine as long as I warmed it up and didn't go over mountains. A two barrtel would be better for an NA, lot's of ministock guys love a holley 2 barrel.

http://www.summitracing.com/parts/JPT-97000/

 

Interesting. That manifold looks similar to my old Jaytech, just with shorter runners. My holley was a 4 barrel single pump.

 

http://www.holleytv.com/featured_landing.php?reset=true

http://www.hotrod.com/techarticles/e...ing/index.html

http://tgsperformance.com/holley.htm

 

I bought a autozone rebuild kit because it was leaky when I got it. Thats it. Did some small tuning with the needles for the first week or so and it ran great the rest of the year.

Just a basic Holley 600 single. 1850-C if I remember right. Basically the same thing in the Racing Beat kit except theirs has mods done to the internals already.

 

One will only work as well as you know it. I have done both on multiple cars, both rotary and piston and EFI is hands down a lot better..

Just because the car runs fine during different temperatures changes, doesn't mean its running optimally. As said a carb cannot make any air temperature change, its kinda of a known fact....

 

Those are great supporting vids. Thanks man. I am taking out a small personal loan to do some minor things to my car before winter comes, carb conversion will be one thing on the to do list. I found a used racing beat carb manifold for $150 on ebay. I might go for that. I am also in search for a stock gtu spoiler and possibly a bodykit.

 

Well of course. It's done to keep it running optimally. That doesn't mean it HAS to be done. Just that it'll be lacking a certain % of performance during the temp change. I never messed with the jets on mine, tuned it once when I first got it and it ran smoothly year round.

I'm not going to deny that EFI is a superior system. I'm actually in the process of going back EFI in my car right now only because I'm going turbo. Blow-thru setups have the same issue (the tune changing depending on temp) and I don't want to have to worry about that as it is a bit more of a issue going lean on a turbo car.

I've driven friends EFI cars and other carb'd rotaries. If I were to stay N/A, I'd definately stick with the carb. It may be my personal preferance, but I like the way the motor runs on a carb compared to EFI. Turbo cars definately need to have full control over the motor though.

 

I would want to turbo it but I dont think thats going to happen anytime soon. But another big question is would it really be worth it seeing how I live in wisconsin and the weather/temp/humidity changes every 15mins.....

 

Turbo and carbs = blown engines.

 

Actually, now that the kit costs $900ish dollars. I would say keep FI.

 

Well, if you just want the car to simply run rather than run well, then a poorly-tuned carb is just fine. However, I don't see much point in spending all the time and money on a carb conversion just to get less horsepower and worse gas mileage, even if the car is only intended to get you from point A to point B.

A carb conversion is generally a downgrade, but it does have merit in some respects. I happen to like spoilers and body kits, although some people may disagree with that opinion. You will find a lot of different opinions on things like that. However, using money that you don't have in order to buy parts that you don't need is just plain stupid, especially with the current economic situation. Please don't be stupid.

Humidity does not really change the engine performance by very much, but it does affect the detonation threshold. Temperature, on the other hand, is a huge factor in engine tuning.

I bought a brand new NA RX-7 in 1988, and it was a wonderful car in its stock condition. Unlike a Honda economy car masquerading as a sport car, the RX-7 does not need any additional modifications in order to be a fun sports car. My recommendation is to enjoy the car as it is, save your money, and upgrade items only when they wear out. Trust me, as old as these cars are now, you will have plenty of things to upgrade as they wear out, lol. If you want to buy dress-up items like a spoiler or body kit, I highly recommend you only do so with extra money rather than borrowed money. This advice comes from a financially-independent 21-year RX-7 owner who would like to see you succeed in life.

... or horribly running engines. Only the best tuners can make a turbo carb rotary run well. Everybody else is doomed to failure.

 

I had a buddy do both on an fc, carb and efi. In the end, he went back to the factory efi.

 

Thanks for the info evil avaitor. Well I guess Im sticking with EFI. But I was also debating on t3/t4 turbo kit. Ive seen the n/a turbo discussions but they seem like a stretch. So I have yet to think about that.

 

this isn't really true.

one of the cons to carburators, and its not obvious, is that to changes the jets, you have to have them, which means you have to BUY them.

even if you say buy a weber, and then buy all the jets and venturi's and such that are recommended for your engine, its about $200 worth of stuff

AND you have to wait for them

a keystroke is free... you don't have to wait for it to come from italy either

just for this reason EFI > carb.

 

Do more searching if your thinking turbo, #1.. T3/T4 is not a suitable turbo for a 13b. Go full T4.

~Mike..........

 

As stated above, the T3/T4 is generally too small for our engines. You would be better off with a T4 manifold and a water-cooled 60-1 or T04E 60.

Yes, the NA/Turbo conversions are a major pain. That is why it is better to just sell your car and buy a Turbo II car if you want to go turbo. Also, there are occasionally very good deals on cars with lots of mods. While somebody else's project may be a bit of a gamble, you can pick it up for a fraction of the money that the other person spent.

I think it is better to save your money for necessary parts and repairs right now rather than focusing on unnecessary parts. However, it doesn't hurt to keep other parts in mind in case you happen to come across a good deal.

 

I have blown quite a few carbbed engines to figure out what all has to be done. Definitely not something for a novice.

I just got off the dyno an hour ago with a carb'ed blow through 13b. Impressive numbers so far...