Tuning Holley 600 for street ported 12a
 

Iam looking for info on tuning a Holley 600 for a street ported 12a.
The only starting point I have so far is to start off with 58 jets for the
primaries and 56 jets for the secondaries. I dont have it on my car
yet, but should be on shortly.

um, 600 is a little big for a 12a street port..

Are you planning on drag racing this? cause holleys suck on turns, unless you buy new float bowls.. (it is because how they are mounted on a rotary)


Can't offer a whole lot of help beyond that though sorry.


-Zach

I plan on having it on the street. I know about the center hung
float bowls already. Right now I have just installed the 600 on
my stock 12a. It is running pretty good for not tuning it yet.
All I have done so far is remove the choke and install 57 jets all
around. The speed shop didnt have the 56 and 58's. She easily
eats 2nd gens with out a problem.

Now, street ported, just brakeing it in. Runing like a champ. Got 57 jets in the primaries and 62 jets in the secondaries. Still need to get the center hung float bowls or notched float bowls with jet extensions? Not sure on which one works better. Any suggestions?

yeah... webber 48 ida... its easier to tune

Easy is not always better!

Run your two adjusting screws all the way in and then back them out 2 1/2 turns. Adjust them from there in 1/4 increments until you get your desired response.

Sounds like a plan, I will try that and see what happens.

what happened?
 

Hey there, Im also tuning on a 600 with streetport 12a.
Wondering what the outcome was.

Iam currently breaking in my engine, so I dont have any solid runs. Iam running 57 primary jets and 65 secondary. Everything else is basically the way it came from the factory. I removed the choke added a 1" spacer under the carb and have a screw to make my vac sec open slightly after primaries start to open. What is your set up?

Also, it seems that more people at the track use Holleys than people on the net? There is not much info here, but doesnt mean it will stay that way! There is more people here with Webbers than Holleys?

Breaking in mine too,
I started with 57 primaries but have rejetted to 62's
A # 7 metering plate, pluged off the power valve. #37 squirters and converted to a mechanical secondary system. Ive still got a little tuning to do but it runs well.

Iam not sure what #squirters I have installed. I had the same size jets as you run currently and ran good but felt like their should be more at the top of the rpm range, that is the reason I stepped up to the 65's, but doesnt seem much better, if it is it is slightly.

Is the #7 metering plate your 62 secondary jets? Are you using the plate instead of a metering block? I dont know too much about the Holley's Iam Learning as I go.

I am just learning also, yes the plate is in place of the block, I had the #7 plate is the reason its in there, I have read of these setups using the #8 plate I would like to get a "list" of what the plates are comparitively to jets. anyone???
What is this "screw" to help the vac secondaries open up? how do you have that working, Ive got a vac sec pod that Im just not using, Im still working on the mechanical linkages and there ok but not quite right. Getting the cams lobed right to go WOT is testing my patience.

When I bought my metering block it had a list of # plates and comparitive jet sizes, I will look to see if i still have it. If I do I will post it for you. Also the "screw" I talked about, is exactly that. A simple screw that makes the secondaries open. I will post a pic of the setup I have, maybe tomorrow. It is simple and alot of people dont like it?

Very cool, apprieciate that. lol alot of people here dont like a lot of things, whatever works, Ive built a wide body car so according to many on this board ive allready commited sacrilege. Been building this for near 6 months now. Almost ready to post some pics and watch the origianal minded folks go nuts. lol

Body kit sounds tight, I always like the idea of more rubber on the ground! I will like to see the pics, I would post one of mine but this peice of shit wont let me upload my pic!

I got the pics posted(screw trick and Holley plate# to jet size conversion)

http://www.tamparacing.com/gallery/s...=7&thecat=3018

http://www.tamparacing.com/gallery/s...=7&thecat=3018

I see, I made a new arm to open mine quicker, same Idea though. Thanks for the jet conversion chart no wonder im having troubles feeling like a lack of power, My motor is starving a # 7 plate = 53's lol Ill get the #8 in there asap.

Yeah, I was wondering about that jet size. I had thought you said you had a #7 in there. Do you have your secondaries opening up before your primaries are fully open?

Not saying this is right: The way mine is set up, is my primaries open about(guesstamation) 1/4 of they way, then my secondaries start to open. Not sure if it is a good set up, but seems to work for me. Just putting out the info on my set up.

Im also opening at about 1/4 after the primaries. Ive read anywhere between 1/4 to 1/3.

vac advance?
 

813, curiosity, what did you do with your vacume advance? lead and trailing? full vacume on both?

#8 update
 

By the way I had to order in the #8 metering plate and it wont be in until Friday. My car goes to the paint shop on Friday and will be gone for 10 days so looks like it will be awhile until I know if weve found the cure. *sigh my impatience is killing me.

My vac advance has NO vac! The trailing advance is completely advanced and screwed down to lock it in place(where the vac tubes hooks to on the distributor)

Currently Iam looking into Direct Fire Ignition. One of my igniters died and I have a friend that wants to get rid of a MSD 6a box and that will take my dead igniters place. Supposedly it is the only way to go when it comes to ignition on a rotary!

If the trailing is not advanced completely it will vary while driving? That is what I was told. I think the #8 plate will work alot better, I would lean out your primaries, atleast go back to the 57's? Run it first you never know?

I read that too, Your not running any vac on the leading side either? I started to set up that way and an "expert" here told me it would not work at all..... That there had to be a stagged vac assist....I would rather get rid of the vac entirely too. So just advance the trailing edge, lock it down and cap them off?
Im going to try the 62s first and go from there. Im still hoping that the plate gets here prior to Fri. So I can try it before its gonefor the paint.

A "expert" also told me that it is more acurate to leave the vac advance disconected? I have always run my Rx-7's with out the vac advance? I also hope you get the plate soon!

amazing how many experts there are, lol,
Any case I pulled the vac and locked down the trailing edge @ full advance. took a little ride, Truth is I notice very little if any difference. So out they stay. I obviously capped the vacume on the carb, What about the pods on the dizzy, any need to cap them? whats your "expert" say?

I have changed out my primaries to 62's, I was wrong about it being too rich! My car is running alot better with the richer primaries and I am thinking about trying 65's, like my secondaries. I have also found out the 600's with th vac secondary dont have adjustable air bleeds, I now need to look into how to tap them and make them adjustable. Good thing I have an extra 600 laying around! I think since the air bleeds are supposed to richen higher rpms it should make my engine really open up the way it should?

Very cool, I just got my metering plates in yesterday as the car was late getting back from the paint shop (looks sweet) any way mine is running much better with the 67s in the secondaries!!! Im still a little off on the tuning, a mild stumble as the secondaries come in and my wot is not to my likings, however anyone that wants to claim that the 600 is too much carb, well, thats just not true!

That is weird? A stumble when the sec come on? Do you have the floats set at the correct hieght? And proper fuel pressure? The fuel pressure should be 6psi and hold it through hard excelleration, mine is about 6.5 but will drop to about 6.

Personally, I havent capped off the vac advance, I would assume it is personal prefference?

yeah the floats are correct and im running rgulated 6psi so I should be good there, Im think im just off on the air/fuel
Any way heres some pics of my girl!!
http://www.awesomeart.net/4.jpg

When I had my old engine in, stock port, mine would stumble at first excelleration and when the secs came on, but not any more, with my street port. I had also moved my screw a little closer to make the secs come on earlier, I had thought that might have helped?

Tight ride, Iam not sure about the front though? You should take another pic with out the shadow. What size rims and tires are on it?

Take a pic of the engine, and how do you make the pic go on the bottom of your post? If I knew how I would show you my ugly duckling! I NEED a fresh paint job!

about the pic, reply from the post reply link, there is a little button on the panel that says "img" click that and it will ask you for the url where your desired pic to be posted is located. type it in a violla.
The tires are 265/50/14's there monsters for sure but man do they hook up. Ill have to get another pic on a sunny day, its raining here and shes locked up in the garage. I set my primaries to come on earlier and the stumble came on earlier but when I delay the secondaries the power band delays and the obvious issue of getting them synced to wot comes in, I think I just have not invested quite enough hours into the test and tune part of the carb. Ill get the pics asap. look forward to seeing the duckling, If you had seen my girl before the tlc (and about 4K) she was just a poor old first gen destined for the crusher, sad sad shape.

I dont underdstand the whole url thing? for the image.

I would love to have those tires! ! ! ! ! ! !

url is the www address where you are haveing your pictures hosted eg. http://www.yahoopics.com/yourpic.jpg

oops the board automatically made that example a woriking link, it doesnt go anywhere, but you get the idea that is what it should look like just with your info in there

I dont know, I tried it one time with the pics of the jet conversion paper? Maybe, I will check out the yahoo site.

The yahoo site is just an exampe, that is whereever your pics are hosted, it just as well could have been, geocities, ipix, aol, you just have to have one of those services host your pics. your internet provider may allow you some place to store some pictures without haveing to pay for an extra service.

My ca'

Right on man That car doesnt look bad, your right she needs to freshen up the paint. that engine looks about like mine just with out all the vacume secondary stuff. Ill get pics up here in a bit.

Excuse all the dust I havent washed it down since the paint shop and its nasty under the hood.
http://www.awesomeart.net/carb.jpg

Ive adjusted on the mixtures for awhile last night and ive got it running pretty good. Its not yet to my likeing but progress none the less. Ill tinker some more this weekend and see if I cant get it right. Im 2 1/4 turns out on the screws, where did you end up setting at?

Whoa dude, I just noticed off that pic, just below that vac secondary pod is a vacume hose... Ive got mine tapped into the break boost line it looks like if Im not mistaken that yours is plugged off? is that right, and theres no problems with it? I was thinking that the vacume there was a necessity???????

That vac is for the brakes and I have my intake taped for it, like stock, so I dont need it. Damn! You NEED to get headers. Rotaries run like shit with the stock exhaust manifold!

I have not messed with the mixture screws, dont know much about them, what do you know about them? What does it control?

air/fuel ratio = lean/rich

I dont know man, I posted on yahoo and still not working for me? unless you see a pic, I dont see one?

Air fuel mixture? I havent read anything on it? Which way is rich and which is lean, is in lean, and out rich? That could really help me, the only way I knew how to richen the mix would be with the jets for low to mid rpm and air bleeds for the high rpms. That is just what I have read? That is the reason why I thought I needed to tap my air bleeds and play with that. I want to run it rich as hell then start to slowly lean it out, I WANT a o2 sensor to measure the mix ratio. Where are the mixture screws located at?

That is my understanding yes, the 2 screws Im refering to are on either side of the primary fuel bowl. From what I understand (now this comes from an expert and weve talked about that before) In is lean, too lean is very bad. But it makes sense to me as you back them out (recomended 1/4 turn at a time) you can smell the exhaust richen and start to see the smoke from the exhaust. Im told to just richen it enough that it doesnt smoke and go back in 1/4 turn. hope it helps and if anyone else has info on this Id sure like to hear it too.