Hi all, I recently put in a Street ported 12a into my 85 RX7, getting it in there was the east part.
It came with a Webber 48 IDA.

Now for my questions:

1. When I am running the car I hear a buzzing (electrical) sound coming from the trailing coil.. changed the coil but still get the same sound. (maybe wiring will check tommorow)

2. My stock 12a put more power to the ground then this thing does now. it holds Idle great can even bring it down to abut 100 RPM but it starves at top end and has very little torque.

any suggetions about tuning the webber I have a whole bunch of jets and tried a few combos but nothing seems to work it still Bogs down at WOT I am thinking the Float is set too low but any input would be greatly appreceated.

Max

 

Here is a link that explains alittle about the Weber carb.

https://www.rx7club.com/1st-generation-specific-1979-1985-18/beginners-guide-weber-ida-568448/

Also do a search with the terms Weber IDA
Scroll down to the bottom of this page and you will also see more related links for threads.
When wackyracer sees this thread he will probably give more info. he's the resident Guru on Webers.

 

Check your coils at night time. If you see any arching, check your plug boot around it for holes or tears, your coil for cracks, you distributer rotor and cap, and all the wiring in between.

 

Yep, check the cap/rotor for sure. Man in Black just found that out at the race this weekend. Thought he blew his motor, but actually his rotor totally grenaded and fell out in pieces when he took off the cap. This could easily explain the lack of power too. Hows your fuel filter, by the way?

 

Fuel filter is new. I will check the rotor cap right now will let you know

 

post your IDA's specs such as jets, venturies etc and your observation in each combination.

 

What method are you using to set your spark timing? When using the Weber race carb, you need to set total spark advance to 24 deg BTDC on the leading ignition at 4000 rpm.

You also need a very free flowing exhuast system to unlock the potential of the street ported 12A. That is why Racing Beat developed their $700 "streetport" wchaust system.

 

Okay I have figured out my problem after getting a timing light. my Leading igniter was shot, replaced and the power is there..

i am using a timing light and set advance at 24 deg at 4000RPM.. on leading

also purchased an AEM wideband today will install it tommorow.

40 Venturies the jets that I have installed I have 175 Main (fuel) 160 Air.. the air compensator jet is the biggest I have but I have bigger/smaller fuel jetts cant find any in toronto.. if you could point me in the right direction where these could be purchased.

The car runs decent have madd bog but that is probb because of the Accelorator pump setting.

let me know what you think I know I should run something allong the lines of 150 Main and 200 Air comp but I need to find more jetts..

thanks for any and all input

 

To prevent stumble around 3K, use larger idle jet to have a smoother transition.

You got it backwards on the jets. It shoud be 150 air and 200 main.

 

Thank you I will try that I found 150 Air jets and I have 200 and 210 Main jets I will play around with that today.. will have some time later today to weld the bung onto the exhaust..

where on the exhaust should I go.. I am thinking after the RB header but the AEM book suggests 18 Inches from the exhaust ports or if im running exhaust temp of more then 800 deg C then I should go further back.

 

Unlike conventional 02 sensors that need heat to function, wideband sensors do not hold up well with heat. Put it further back to keep it alive. everybody: What are typical exhaust temps on modded engines? I know the stock systems are HOTTT!!!

 

Bung in my RX-3 for dual air/fuel gauge which I installed years ago for light show. Except it didnt last long as it is too close to the exhaust ports (appx 12").

I have an dual EGT also mounted further back which IMHO much reliable that a a/f gauge for tuning

 

mounted mine around 36 inches back where I have the header going into one.. I will see how long that will last.

about the exhaust temp its hot I dont know how hot but I can cook hotdogs on it for sure

time for tunning I have all day its a bit cold but I can deal with that...

right now as it stands Im only at 12.3 12.4 AFR