i have the stock stacks too so i will see how they compaire, any advice on current jetting would be great
the engine is just a standard street port currently
thanks

 

lol right now it runs okay with 185 main and 165 air. i put in 220 main with 165 air and it's even leaner up top. with a main that big it allows even more air through... now I'm waiting on smaller a/c's and 205 mains

 

A bigger main will make you run rich, there is more to tuning than just changing air and main jets, start off with timing,float level,5 psi of fuel pressure, correcr spark plugs, once that is done you can begin with jetting......good luck to you

 

since this tuning thread is back up and going when i was reading in the HOW TO MODIFY YOU RX7 book it mentions in the tunning section (pages 56/57) the addition of a 1/16" hole in the lower portion of each throttle plate for cars with altered port timing.

is anybody running IDA's with this mod? what exactly does this do for tunning?

this mod seems like it would allow a larger idle jet to possibly help eliminate off the line bog, while leaning out cruising afr's, but i dont want to just drill out expensive throttle plates and find myself stuck at a 1500rpm idle and so lean that no jet is big enough

so has anybody heard of and actually tried this out?

 

yes, it is called "progression hole." The stock unmodiified IDA. including the new ones from racing beat only came with 2 progression holes per barrel. Rotaries need 3 per barrel so you have to drill it out.

 

Wacky
ive read up on this too but is there a exact location for the hole or is it just where you can drill it without opening up the other 2

 

I am not talking about the progression hole mod( it goes up as high as you can put It and of similar size as the other 2 )

What I was talking about is a mod to the throttle plate itself, is this an old way of getting the same results as the progression hole mod or something completly different

 

What size accelerator pump jets do you guys use, and with what size choke?

 

Good question? I read that you drill an added hole where the progression hole is on the carb. on top of the carb behind the plates there are two brass plugs you remove these and drill a hole next to the other 2 holes. It doesnt say what size hole either. Would you have to dissasemble the carb to do this mod to eliminate getting shavings in there?

 

I dont do mods on the throttle plates or butterflies. But I always replace them with the thinner ones plus the progression holes. Jack of Jay-Cee enterprises modded my 1st IDA over 10 years ago but I still go back to him for updates

 

A bigger main gives your a richer mid range and leaner top end.if the a/c is unchanged. At least that's what the wideband shows it could be wrong... lol smaller a/c will fatten up the top end. By top end I mean 7k+

Progression mod explained here:
http://www.aircooled.net/gnrlsite/re...idarebuild.htm

I run 44 main chokes, and as far as I knew there was only 1 size accell pump jet. you change the rate by drilling it out or changing the relief in the float bowl. I run 0 relief.

Wacky supposedly the made in spain later IDA's had the 3rd progression hole from the factory. My Italian one didn't have it.

 

really? I have worked on the new style IDA's and they only have 2 progression holes.

 

So you do have to dismantle the carb before you drill the 3rd progression hole. What size drill bit? the one on the pic looks extremely small. What are we talking here like a number 60 bit

 

you have to remove the plug below the air/fuel mixture but before you start drilling, you also need to remove the air/fuel mixture needles, venturies and the carb has to be @ wot. This is to ensure that the above parts doesnt get damage. Look at the modified section, there was thread on "HOW TO."

and yes, the size is either in index or number drills.

 

my brand new made in spain IDA has only 2 progression holes.

What size do you guys DRILL out the pump jet to? I started with stocker 55 and have gone up to 70 and the pump mixture is still lean per wideband. Gonna try 75. 0 relief in float bowl.

Dellorto used 90 so I can assume I need to go richer.

 

Wow looks like the local guru was wrong. lol. As far as the pump jet I've never drilled mine. I wasn't even awair that they came in different sizes for the IDA. you can drill it out more or just use a bigger main and it should richen up when you get on throttle.

 

Turned out my inlet/exhaust bypass valve on the bottom of the float bowl for the accelerator pump circuit had a crack in it, and it was bubbling fuel up and into the float bowl when moving the throttle.

A new closed "0" bypass valve and i'm back in action. Also drilled the pump jets to .80mm and now it sure is richer than it was.

 

just got my rebuild kit in and new jets. I'll let you guys know how it goes.

 

Update: I got a parts list and it shows the IDA pump jet only available in a .070 size, so you can buy new ones and drill them out from there. Currently I have :
65f10 idle
120 holders
205 main
165 a/c
f-11 etube
0 bypass
3.0 needle

Caur runs okaybut still stumbles on cruise. I'm adding the 3rd progression hole this weekend. Anyone know what size drill bit to use?
I tried running 75 idles, but they were way too rich. it stumbled even more witht them in. if I run any A/C smaller than the 165 I get spark blowout above 7k. Atleast I think it's spark blow out. it feels like I'm hitting a soft touch rev limiter.

 

use a different spark plug wires. I had similar problem around 7K before due to bad magnecor wires.

stumbles at cruisng speed? stumble or jerkiness? care to elaborate?

 

What does your air/fuel meter say?

I ended up with 70f10 idle fuel jets and 120 holder. The 65 was too lean.

 

How you guys set up the idle mixture? What would be a good ballpark range?

 

They're new RB wires. My narrow band shows 1 green led and 1 orange right on the border of rich and stoich when i'm cruizing. When I cruise at exactly 3-3800 rpms it just seems to cut out every 2-3 seconds. when it does the guage goes full lean. for a split second. It WOT near redline it's a full 2 bars into rich. it's an autometer procomp gauge. I need a wideband. It's on my Christmas List...

 

At that RPM it's on the progression circuit and starting to bring the main circuit online. And do the 3rd progression hole mod.

Try the 70 idle fuel jet. And put a 10 micron Fram HPG1 filter right before the carb.

 

Yea I know. It's a bitch. I blame it on the big chokes...
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p.s. Palin is hawt!