I just bought a 1984 GSL-SE. Things done (engine wise):

Weber DCOE 45 + 1 piece manifold (pierce)
RB header, custom piping to a generic muffler
Fuel pressure regulator (+ all other supporting things for a carb swap).

Anyhow, the car is misfiring and running incredibly rich (flames, lots of gas smell, popping, etc). I believe the richness is hurting the performance by a good bit.

I know there is tons of information about the 45 Weber floating around, but I really can't comprehend some of the stuff that is being said (new to carbs). How can I recognize what size jets/etc I have in the carburetor? What are recommended sizes for the parts inside it (for maximum power on a stock port, I suppose. I'd like to hit 14s in the 1/4 if possible...)?

Also, what spark plugs/wires should I put on it, and how can I check the timing ?

I realize these are all newbie questions, and I've searched, but I'd appreciate it if someone could take just a few minutes to help me out. Thanks!

If this means anything to anyone here, it is rxseven07's old car.

 

First let me say welcome to the forum and the rotary world!!

I would run NGK's either BR8EQ-14 or BR9EQ-14 For wires some fat 8.5mm wires!

I dont know how to tune a Weber, So I cant help you there. There are some really good guys on here with super carb knowledge! Im sure they can help you out.

 

84FB,

there should be a cover on the top of the carb that is held on with a single nut (solexs and mikuni's) and I think its same basic design for the weber side draft (though it might be 2 nuts like the IDA or IDF has.

pull that cover off and inside you will see four (4) flathead/slotted looking brass screws with holes in the center

these are you "jets" and emulsion tubes.

2 of them will have 3 pieces: you have a jet on the top, and a jet on the bottom of each, and the center tube portion is the emulsion tube.

then you will have 2 of them that are two pieces a jet and a tube, these are the idle/low speed jets.

is it rich at idle/low speed, or at medium speed/high load?

this will determine which you have to dink with.

there is also a distinct possibility that the float is not set correctly. often times people make the mistake of changeing jets trying to correct a improperly set float, or a bad needle valve/seat (these are inside that carb), and you should really get a manual before you go that far........

the jets themselves have stamps on them to identify the sizes IMPORTANT BEFORE YOU CHANGE ANYTHING WRITE DOWN THE CURRENT COMBINATION this will allow you to return it to its current jetting if you make a clusterf*#k out of it

fingers are tired, PM me if you need more info

kenn

ME + Wild Turkey =

 

Thanks for all the helpful information so far guys.

It is rich all the time, haha. I adjusted the air screws on top of the carb and it is a little less rich at idle now it seems, but other than that I'm dumping/smelling fuel all the time, and flaming. I think it all needs to be toned down some, but I'm not positive. Are there any good books on tuning Webers?

 

is anyone else seeing an issue here............

GSL-SE converted to carb.................

but why?

 

i use NGK titanium plugs with 4 prongs and nology 8.5mm wires and engine runs like a dream...

 

check the timing first thing. aim the light at the main pully and a white mark should line up with a little metal bar thingy above it. ( for the leading plugs, then you do it for the trailing plugs it will line up with a different mark, {red?} on the main pulley.)

 

From what I've seen here on the forum it is important to have the correct size throat as well as jets. You want to have the right CFM. My guess is that if the throat is too large the AF ratio will be screwed up and could result in excess fuel becoming evident by smell.

My recollection may be faulty, but when I was considering a Weber it seems that 45 was too large. I also remember one guy posting that he had to neck down his throats to get his Weber running right.

Checkout past posts by STERLING and RX7CARL, who deal with this regularly and have actually made measurements.

B

 

I'm actually starting to see a trend here, a lot of people are saying that they have a GSL-SE and that it's carbureted. I think that mazda may have still been experamenting witht the fuelinjuection system and trying to see exactly what they could do with it. So what might be happening is that some are fuel-injected and some are carbureted with a not so stock port to gain the power lost without the fuel injection.

The only reason I say this is because the first car I ever owned was a 1982 Mazda RX7 GSL-SE that my grandfather gave to me. (he was the only other owner of the car) and that one was carbed as well. (And yes it was supposed to be fuelinjected, but the whole thing came stock with a lot of things you don't usually see on an '82)

 

oh, and I use Denso Platinum plugs and double silicon wires.

 

I don't buy any of that.The -SE's were all fuel injected,and they were not available in the US in 82,or anywhere else for that matter as far as I know.I have seen,and heard of Dell'orto,holley,mikuni,webers,etc carbs on GSL-SE's,and any other RX-7,but they were not from the factory.I have heard of the stock Nikki carb on a 13B powered GSL-SE as well,but that wasn't from the factory either.The only carb from the factory I have ever seen on an RX-7 was on the 79-85 12A powered cars,and the carbs on them were all pretty much the same with small differences over the years.Everything else was fuel injected here in the US.

Chris
79 RX-7 GS
83 RX-7 LE
74 RE/PU
92 Cummins diesel

 

All SEs came fuel injection. Mazda did not had to experiment with FI or carb since they had already mastered both. The only SEs you are going to find with carbs on the are the ones that have been modified at one point or another due to a number of reasons. I have two SEs, both carburated and tha is by choice.

 

Throat size??? you mean venturi's probably yes it is important, however this will not by itself cause you to run rich, it will have a definite affect on responce though. having a overly large venturi will kill bottom end, and too small of one will kill the top end.

I personally have never dealt with the side draft webers, however in the downdraft world the 48 IDA, or IDF is the carb of choise for a NA rotary useually you are running from a 38~42 venturi depending upon weather you are stock, street, or small bridge ported.

Monster bridges (J-bridge ports) and Perry Ports require the 51mm modification to the 51 IDA in order to realize there potential, and in reality the perry port prefers a 55 mm or larger

for a stock port~street port a 38~40 venturi will work fine, after that its a matter of jets and timing the emulsion tubes should already be correct if the carb was originally modded for a rotary F-7 ~F-11 for the e tubes with a F-10~11 being what you want for a stock/street port.

Ken

 

New question(s): I searched, guess I'm going to run 20W50, but its going into winter. Should I stray away from Mazda's recommended weight?

Also, what type of coolant should I use? I know that different manufacturers use different types, but I'm not sure what to put in it. thanks