chris_stampe

I have an 87 carberated na (maybe soon to be turbo) and I bought it about 5 months ago. When i got it the timing was all screwed up and it would cut out badly anywhere past 5k, now ive tried to fix the timing, but the mark on the pulley looks too advanced, and the trailin looks too retarded. btw i can barely tell where the marks are, is there any way to clean the pulley? The reason im posting this is that my car doesnt make any more power at 6k than at about 4k or so. It doesnt cut out now (untill about 6.5) but it must have a really flat power band, and looking at others dyno sheet they usually make a huge hp gain after 4k. You guys i desparatly need help. I lost to an old pos supra turbo that my friends eclipse and civic beat easily. For god sakes i lost to a 95 civic dx with only cold air and plug wires by nearly 2 car lengths. My clutch is also starting to go bad so I dont have very good launches any more. If i cant get this thing to be fast im gonna have to sell it instead of putting more money into building it up. Cuz at the rate im goin it might someday be a 15 sec car (witha turbo). Please Help!!!!

hyperdaddy7

it is carburated? the reason why tyhe other dyno charts show a big power gain after 4k is becasue the 5th and sixth ports open and the secondaries kick in at this time with the fuel injection setup. I'd say the reason why your not getting anypower after 4 k might also be becasue of the carburation setup you have. I would check the all the jets and make sure they are all clean. As far as the timing goes, i can't really help you much, but i do know that a few aftermarket ecu's retard and advance the timing quite a lot and manage to get a lot of power out of them.

good luck hopefully i was of some help

peejay

If it's any consolation a T2 is also a 15 second car

What KIND of carburetor is on it? What kind of manifold?

drake696

what kinda of exhoust are u running on it is it is startit puipe right through u wont have andy back presure and that is y the 6 oports open up how ever when u open the 5th and 6th port u will loose in gas milage and in low end power but every where from 4000 rpm and up it's going to gain quit a bit

chris_stampe

Well its a Cartech 2c turbo manifold that doesnt have a turbo running on it now. The previous owner aparantly took it off and changed the jets. Its 2 double barrel carbs. The 5th and 6th ports do not open and close they are always open so that shouldnt be the problem. I still cant get it to stop cutting out past 6k rpms even though ive adjusted the timing (and that helped quite a bit) I have the stock split dual with a new pipe welded in from the exhaust manifold to the silencer, then it splits and goes to the 2 stock mufflers. I have a k&n filter and thats about it. Spark wires and plugs but nothing thats gonna do ****. THanks

amemiya

Thats your problem it's carburated

peejay

It sounds like it's running rich at the top end. Without being able to drive it, it's hard to say. What you really need to do is find out what model carbs they are and what the pervious owner did the screw them up.

amemiya, wtf?

tmak26b

Go do some tuning

Mazdarules

How are you expecting to turbo a car with a carb? Am i the only person that thinks carbs are useless, personally I would never put a carb on a FC. The car comes with a good fuel injection system.

Basically your problems can be traced to the fact that the car is not designed for a carb at all. It sounds like you need to adjust the carb, the mixture is probably out. As for the timing, Maybe someone can give him a little more info on this. Download the service manual on fc3s.org for info on adjusting the timing

peejay

Turbo + carb is possible, LOTS of people do it everyday, manufacturers used to do it, etc.

Cars are not "designed" for carb or fuel injection... the car doesn't give a crap either way and neither does the engine as long as the air/fuel mix is correct.

Mazdarules

Thanks PJ. Carbs and turbo's are not something I'm really familiar with. I would say that the FC is designed for fuel injection. The computer, sensors and other systems on the car are not designed to be used with carbs. In my experience carbs waste fuel and some are hard to adjust properly. The whole auto industry didn't ditch the carb because it was better.

peejay

You're right... you eliminate the computer and all that crap when you go carby A well tuned carb is a beautiful thing. You can thank the EPA for fuel injection, for better and for worse. The manufacturers use it because the government requires it.

As for wasting fuel... sure a poorly tuned carb will waste fuel. So will a poorly tuned EFI setup...

Icemark

well not quite correct. I carb can not adjust to optimize the mixture at part throttle positions. Its either on or off. Most newer designed motors do benifit from the direct injection at the intake and atomization that a properly fireing injector delivers.

It also (unless it is a side draft) can not deal with higher G's in cornering and stopping which wash/slosh the gas right up the sides of the float bowl.

A carb is perfect for a drag car or simular application, where you are at WOT all the time, but it sucks comparied to a FI system in 90% other cases.

You also wrote:
You are wrong there. FI is better in any application where you are not WOT. You don't see carbs in F1, F3, or CART. They don't have a restriction against them. They are not used because carbs are not as fuel efficent as FI. They don't use carbs because the power band is not as even. It is harder if not impossible for them to optimze the fuel delivery to the engines power curve with a carb set up.

There is no EPA regulation against using a Carb at all. the only regulations even remotely related are Fuel efficency and emissons. If you had a engine which could run as clean and efficent with a carb as the comparible FI engine, I am sure Detroit would be all over it just for the cost issue.

If you need a mixture optimzed to the engine at all throttle positions not just WOT, FI is a much better application.

HAILERS

Can you tell if the timing is advancing. As in putting a timing lite on it and reving just over 1000 rpm. Does it advance when you do that?????? Story time..... I have a 82rx7. One day just for the fun of it , and because I had an extra ECU, coil assy and time to goof off, decided to put the N326 on the 82. I strung the wires, put a cas in the car, installed the second gen lead and trail coil assy, and sure enough the car started and idled just fine. Whoopie. Well I drove it and it started to bark like a dog. Sluggish. I put a timing lite on it and saw no advance over 1000rpm. Stewed a while, then patched into the 82's tps. After that the timing would advance. Ran much better. Was on the verge of installing the pressure sensor out of the second gen, when I got distracted by buying a 87 turboii salvage vehicle. Never got around to doing the boost/pressure sensor. I think most folk use a 1st gen distributor when going carb route. Have fun. EDIT: Before someone jumps me from behind, I know that the timing curve for a 82 is different than what should be for a second gen. This was just a learning experience, nothing else.

peejay

I'm sorry Icemark but you CAN tune a carb for good low-load operation and high-load operation! It's not a simple "on/off" system, there are many circuits in a good carb and you can alter the fuel curve to suit your needs! Even with a single 2-barrel carb you can adjust the idle jet and air bleed (which control mixture up to about 3500 as well as low-load) to alter the fuel curve down there, and the main jets and air bleeds to change to high load high rev stuff. And then you can also play with emulsion tubes and venturi sizes.

4-barrel type carbs are more fun. A box-stock Holley can't be tuned for **** except to get you 90% there, but if you alter it for adjustable air bleeds, adjustable idle jets, adjustable PVCR's, you will have an INCREDIBLY tuneable carb that will give you whatever you want at whatever RPM you want. Carbs are simple devices like rotary engines - their simplicity is why they are so durable.

The EPA does require fuel injection... OBD-II must monitor ALL aspects of the engine control system, a computer can't monitor the inner workings of a carb. Plus it's too hard for a manufacturer to tune a carb for every given possible circumstance, heck it's hard enough for them to do it with EFI. But for the end-user (us) we can do it.

The trrick is TUNING... a badly tuned carb will run like ****, just as a badly-tuned computer will run like ****. Unfortunately in the import world people are afraid of mechanical devices because they don't understand how they work and don't care to understand, just like there are people who don't understand EFI and don't care to. All the engine "knows" or "cares" is that it gets the correct mixture of air and fuel - EFI can do that, so can a carb.

NZConvertible

Peejay, the simple fact is, there is [n]nothing[/b] a well tuned carb can do that well tuned EFI can't do BETTER, a lot better in some cases. Those people who truely understand both carbs and EFI realise this. You can argue the pros of carbs all you like (and I don't disagree with anything you said), but that simple fact remains.

Ranzo

I would have to say that it depends on what your application is. Some engines run really good on Carbs, and I would have to say that a rotary is one of those. In Japan the biggest mod for a Toyota trueno (ae86) is carbs....why, its a easy to do, clean, power making modification that in the long run is super cost effective. I personnally am a fuel injeciton person becasue I am intrigued by it and have studied it but that doesn't mean that carbs don't work. I have seen a 13b carb turbo car put 600hp to the ground.

NZConvertible

Um, why? There's no reason why some engines would run better than others on carbs or EFI.Actually, they do it because the twin Webers they run can flow more air than the stock AE86 inlet manifold. Obviously a custom manifold or twin Weber-style throttle bodies are going to give even better results. Peak power levels at WOT is about airflow and the correct amount of fuel. Anyone can do that with a carb, that's easy. But what about fuel requirements for the other 99.9% of the time?
I've never said a carb won't/can't/doesn't work, just that EFI will always do it better.

peejay

A well tuned carb will not beat a well tuned EFI, true... however the well tuned EFI will cost a hell of a lot more than the well tuned carb! Dollar for dollar you get more HP with carb. If you have the money for Haltech or whatever then go for it, no questions asked. (Hope the stock EFI manifold flows good though - you might need to change that out for best HP results) However you can't take that and then say carbs are garbage. They work, and work quite well.

NZConvertible

Aargh! Stop misquoting me! I never said carbs were garbage, I know they can work quite well. I just said EFI is better. You say "dollar for dollar you get more HP with carb", but that is an inaccurate statement, because all you're talking about is peak hp at WOT. As I've said before, EFI's vastly superior accuracy in fuel delivery means significant gains in low- and mid-range performance, throttle response, transient situations, driveability, fuel economy and more. A carb can't control your ignition for even more gains, run in closed-loop mode for economy, provide cold-start enrichment, control thermofans, boost control, nitrous control, etc, data logging, etc, etc.
As for cost, I know it's more expensive (a lot more for you guys!) but you don't get nothing for free in this world; superior performance costs! Besides, I said "anything carbs can do EFI can do better", so if buying a carb lightens your wallet, EFI can empty it!

peejay

Carbs can and do work well under low-load conditions. IT'S ALL IN THE TUNING.

BTW - Closed-loop is only so the cat is happy. **** it, once you yank that sucker off you can run nice and lean under cruise conditions for EXCELLENT fuel economy and nice clean combustion chambers.

813KR$

I would say make sure the carb is working well, I had similar probs and
switch out the carb. That was the prob for me. Defenitly get the timming
straight that could be the end of the appex seals and engine?

projekt

if you're really talented you could use a few squirt guns filled with gas, but they'd eventually melt from the gasoline...

Barwick

No it's not.. I'm not even running full boost (only running like 5.5lbs) and I'm running 13.7

pillage6

Ever hear of Formula Mazda?

Last time I checked they were using side draft carbs jetted by Racing Beat.

I have a Turbo 2 block in my car and it seems fine with the carb on it.