My 84 12a has a mild street port. I was wondering what grade gasoline I should use. It has a Holley red fuel pump and I only get about 12mpg. I've researched and a street port shouldn't affect mpg. So is it the pump? Sorry if these are obvious questions I'm new to rotaries. Thanks in advance.

 

welcome to the board.

you will be fine running 87.

porting will affect MPG, but how much will depend on a few factors. you mentioned the pump, but you did not mention which carburetor you're running. that matters more.

 

The carbuerator is stock. I'm not sure if it's been modified to allow more flow. But most threads I've seen say they get around 17mpg even with a modified carb or port. So I'm a bit confused. I'm going to order a stock fuel pump and try that.

 

it's not likely to be the pump. with my Carter on a tired, stock 13B (with Dell'Orto and all 6 ports open all the time), i was getting 24 MPG. withe the same Carter on the streetport 12A (with Nikki) that followed it, i was getting roughly the same. my brother's car, with a streetport 13B and Holley pump would get roughly 20 MPG.

you should look to getting a fresh tuneup and then go from there.

out of curiosity, what exhaust system do you have and what plugs do you run?

 

It just had a tune up and when I bought it, it already had full exhaust and headers done. I'm not sure which plugs it has. Hopefully ngk. Is there anyway to check? The exhaust might even be custom, there is a shop near here that does their own machining specifically for exhaust.

 

well, assuming it's in good shape, clean the carburetor and start trying to adjust it.

 

Alright. I'll buy some power foam and I'll try adjusting it sometime. Thanks for the info

 

I was getting bad mpg's and checked my plugs they had build up on them so I changed them and it made a HUGE difference. I was getting a lot of back firing on decel now it's a lot better. Wouldn't hurt to check them even if it was just tuned up. Unless u changed them u don't know for sure

 

Good idea. I'll have to check them tomorrow and I'll let you know.

 

just pull one of the wires off the plug and you should have fairly easy access to the brand and type. removal is not absolutely necessary, but as was suggested above, it can't hurt to pull them and take a look for yourself. see if they tell you anything.

 

I filled up my tank last night and I got 14 mpg this time. It is my first car and manual so I guess I just got better at controlling torque. However I will still check the plugs today and clean the carb sometime.