A: Has this been done by any of the members here for a stock 12A?
2: What hp/mpg gains could I expect to see after doing this mod.
c: How much would this cost?

Thanks everyone,
Chris

 

well doing it on a 12a can be done but it is expensive, cheapest route would be some ida throttlebodies and a sds computer with a 2nd gen cas and coils. it would definitly give you more lowdown power and smoother powerband. i would geusstimate 15hp for doing this cause of the big throttlebodies and stuff..... now if you had a big ported motor it would get more power for you

 

It'd be WAY easier just to drop in a 13B IMO.

 

A Very Rare because it is not worthwhile
B Possibly 10 hp if you are lucky, mpg about 2 mpg
C $2,000 to $3000, but cheaper if you can find secondhand

 

I agree with smnc...I think it would just be easier to put a 13B in it and call it good. Just my opinion though. Have Fun

 

C sounds about right but I'm gonna have to disagree with A and B. IMO it's definately worthwhile, whether it's worth $2000+ is a different matter.

As for the power gains, I read an article in a magazine on converting an Rx-3 with stock port 13B, headers, exhaust and stock carb to fuel injection. They gained hp throughout the rev range with a maximum gain of around 25hp not to mention the improvement in driveablity and throttle response. This was done useing an IDA style throttle body and fuel only Microtech computer. Pretty impressive.

 

see if this helps,http://mrmazda.members.atlantic.net/cfaqtext.html

 

Correct me if I'm wrong, but can't you get a decent used 13B for $2-3k?

12A's only make 101hp, right? And the best predicition after EFI is 25 extra hp? Making 126hp total?

And don't -SE 13B's make 135hp?

So...

I may be completely out to lunch here, it just doesn't seem to make sense to me?

 

Wow.... For that amount of money I would not think twice and get a bridgeport

 

For $1500, you can buy a rebuilt streetport 12A that'll kick out 145 HP with a good exhaust system, stock intake...that'll leave $500 for a 75 HP shot of juice. Why bother with a 13B now? We can all figure out a better way to spend $2000 our OWN way, this guy is lookin' to spend his on EFI. Let's help him with that....

 

Revhead has a magazine that says additional 25hp was achieved in a RX3. Mike Ancas says 5-10% increase is possible, after you spend $1000 for the cheapest EFI kit to $4000 for the most expensive.

Weird things happened in the RX-3 days to boost power. However its rare in the RX-7 world as there are far cheaper ways to get power. The gsl-se gained 36 hp from a combination of 14% more capacity, far more effective rotor seals and a change from carb. to EFI. The carb was detuned to ensure the RX7 got througth emision controls,

Thus I think a 10% increase is what you would expect by going EFI, I agree with Revhead you can get better performance across the range and you can obtain optimal fuel/air ratio throughout the rev range. You have to get some benefit for all that money spent.

In simple terms, EFI should always be better than a carb once you have got all the variable values right in the computer, this is why modern cars are EFI. However not only is it a jump in technology but a jump in cost which makes conversion a very expensive way to get power unless you are a flat out racer.willing to pay $150 an additioal hp. I totally agree with all responses- it just is not worthwhile in a typical RX-7 situation

 

Maybe hes talking about just using the basic used mazda parts from a 13B... But aftermarket fuel injection is EXPENSIVE! I have been pondering this with a turbo and I look to spend a shitload more money.