john smack

iTrader: (12)

So I took delivery of a 3" downpipe and an AEM UEGO wideband
I have a 1/2 bridged 12a with 12at rotors in it, I have two MSD 6al boxes running two msd coils in a direct fire setup and the trailing is stock other than a msd coil,
I had 4 BR8EQ14's in the car and it had a rock solid idle at 750 rpm but as soon as I cracked the secondaries (Not moving just sitting) it would die out. I had gotten some advise that I was blowing out my spark, So I ground down a socket and gapped my B9es to .015 and installed 4 of them and fired it back up. It was harder to start from dead cold and when it warmed up the idle will stay solid at 950rpm for about 5 seconds then it leans out and wants to die I have to blip the throttle.
On the good side it revs right to 7000rpm with ease and has an A/F of 10.6 but when it is idleing it is between 13.4 and 14.7

A/F ratio moves around alot with the brap brap brap.

When I put in the new plugs I upped the idle from 750 to 950 to see if it would stay running and it does the same thing just Idle for a few seconds then it needs the throttle to be blipped.

Can anyone offer any advise?

Oh I am running a stripped down, boost prepped nikki, I am about 13 deg advance with a locked dizzy

Jeff20B

iTrader: (13)

The cracking open of your secondaries while not actually driving the car is what's causing your problem. I have a Nikki I modded with mech secondaries and it doesn't like it when I do that as well (it wants to stall out while free reving up from idle, like your setup).

Go back to the previous plugs and stop opening your secondaries while free reving!

As for the need to blip, perhapos your throttle blades are getting hung up or you have a vaccum leak which you've tuned around to get your 750 idle. Or maybe the turbo blowing into the carb is doing something. I don't know as I've not messed with a turbo setup yet. Good luck

john smack

iTrader: (12)

I thought you are not suppose to use the BR8EQ14's for a turbo application?
What kind of plugs are you other 12a turbo guys running?

bad 83

iTrader: (3)

NGK B9ES Gap them down real tight to .014. Drop your leading timing down to 10 and your trailing down to 0. I'm assuming your dizzy is locked? Make sre you have your fuel pressure baselined at 3psi to 3.5psi. I dont know how much boost you are planning to run, but you need to make sure your secondary jets are at least 190. If it starts popping on the high end, you will need to up the secondarys.

680RWHP12A

i would say try jetting up the primaries, it will make the idle to main transition much smoother, especially with a bridgeport
keep your spark plugs the way they are

yetterben

Guys Kevin has my old setup. Need to keep in mind kev knows very little about carbs. So Sam he has the carb you prepped for me. He also is at some pretty extreme altitude. I dont know if he ever got the car timed its been ahwile since i spoke with him on the phone. kevin bump the idle up if you can set it at 1,000 and see if it goes from there. When it was on my car i had to have the idle at 1,100 with the turbo. Dunno if it was the restriction in the system or what.


On a side note and no disrespect to others. There are only a handful of people on this board who have pulled this off Sam and Rob are two of them, moremazda is another along with wackyrotary. So kevin get all your info from a respected 12a turbo source. Others just give insight but you must be sure bfore going on the road. my idle afm's where usually aroun 8.5.-10 it ran rich as **** at idle wot pulls netted me 11's Its gonna take some ******* around with. But when you dial it in like i did and others have done its gonna be a monster. MAKE SURE double and triple check for leaks on the boost path.

BETTER TO TRASH AND FOUL PLUGS THEN TO LEAN THAT THING OUT. I went threw 3 sets of plugs before i got it just right!

john smack

iTrader: (12)

I am at around 12-13 degrees before TDC with a split of 10 deg that is as retarded as I can go right now without pulling the dizzy and jumping a tooth (the dizzy is turned back as far as it can go)
it was jetted for a stock 12a
right now I am trying to get it to run on the stock boost of the S4 turbo (wastegate is direct to turbo no boost controller yet) it is poping and back firing in the upper rpms
should I change out both the primaries and the secondaries?
wht size should I go for with the 1/2 bridge?

thanks guys for all the help we got our first frost yesterday and I want to take the car for a burn before it snows

yetterben

Another Thing Kev Make Sure There Is Atleast A 1/4 Tank Of Gas And That Your Gauge Is Right. It Takes Alot Of Gas To Feed The Pump And All The Lines!

john smack

iTrader: (12)

Thanks Ben!!
yes my altitude is 2280 feet
I am trying to upload a video on putfile but it is not working for me i will post it when it is up

bad 83

iTrader: (3)

If it's popping on the high end, you need to back off the timing and up the jetting. With you running the half bridge (should have went ahead and fully bridged), you will need to up the primarys and secondarys. Better to jet too rich and back the jetting down, then to be too lean and causing damage. Just my advice.

john smack

iTrader: (12)

So I am obviously going to need to buy new jets for my carb.. What would be a good start for both the primaries and secondaries?
I cannot back the timing off anymore without pulling the dizzy and jumping a tooth... when I tried this to achieve 10 btdc it would back fire alot I guess I may have done it wrong I will try again today and see if I can get 10 btdc.

Sam I bought this car with the half bridge the street port is huge but my next one will be a full bridge........ gotta love the brap brap brap!!!

yetterben

Kevin before you re-jet. Have you checked what i told you to check. Set the regulator

Till the sight glass is just a tad over half. And crack that throttle and make sure your not sucking that float bowl dry first. That gauge on the reg is just crap!

john smack

iTrader: (12)

yeah I am getting a new guage today and I took the day off so I will be checking everything you said ben, as well as re sealing the ACV plate and checking for any vacume leaks. I still cant get a video to upload so I will keep trying

yetterben

I have a feeling the float bowls are going dry on you.

john smack

iTrader: (12)

i got a new fuel pressure guage and it was only at 2 psi so I upped it to 3.5 and I found a small fuel leak so i fixed that. It still wont idle for very long b itself. i checked the timing and I am at about 12* btdc I am fully retarded and cannot bring it back any more and if I skip a tooth back and then advance the dizzy I cant see the timing mark at all and the car wont start at all. I tried to check the float bowls but it is real hard to see in there with the coolent hose and the intercooler piping in the way (me and my buddy couldnt confirm the bowl level) It could be that maybe they are dry, it starts real easy ofter being turned off but it does almost feel as though when idling and not giving it any throttle it is running out of gas and you have to blip the throttle to get it to idle on its own for another few seconds. Now there has been times when it idles for like 5 min by itself before dying out but non the less it still dyes. the A/F ratio on idle is still high like between 13-15 and sometimes hitting 17 for a quick second (usually causes the car to stall)

yetterben

Are you blind the front fuel bowl is wide open to see! There either dry or completely full!

john smack

iTrader: (12)

So it seems I may be blind or my fuel bowls are either too full or empty, also I may have marked my pully on the wrong side of TDC

john smack

iTrader: (12)

here is my timing mark i colored the pin and TDC orange and 10* advance white all the way across the pully

yetterben

its in the right spot you want the mark to the right of the tdc mark. Looking from the front that is. From the drivers side you want it close to you after tdc. I told yah set the throttle cable so it atleast runs on its own for now. If yah have to totaly close the regulator till the bowls are empty then adjust pressure till its just above the half mark. Should be right about 3.5 psi. The car is not going to run for **** on the stock ign system either. For now hook up one msd threw the cap. Make sure you have it wired the right way. Its no wonder its breaking up on the top end when you crack it if youre running the stock cap and rotor with no msd to help.

Are youre plugs fouled out???? YOu are at such a higher alt than me that you are probably gonna have to open that air screw on the carb. You air is thinner and therfore not as dense in the settings. When you move a carb that high up its still getting the same amount of fuel but also trying to suck less dense air.

YOu said it idled with the other plugs. then you switched and no idle??? probally cause the plugs are of a colder variety and need more spark power to light it off. What was in there before!

I want you to set the trhottle cable cause the car has to be up to temp or all adjustments are mute!

CALL ME!

john smack

iTrader: (12)

I do get it up to temp, I had br8's before and the plugs are brand new I am running a msd through the cap, I will close the regulator and run the car till it is out of fuel then I will adjust the pressure until it is up just over half, I will call you when it is warmed up
I will set the throttle cable when it is warm

It wont stay idling for more than a few minuites

john smack

iTrader: (12)

I decided to take the pugs out and see what they looked like
the leading were clean with a little black on the conductor and arm
the tailing looked clean they dont look like they have been fired.
So I put them back in and I started the car and checked with the timing light and I am getting spark to the plug
Do trailing plugs generally stay a little cleaner than leading? They were brownish but not as black as the leading

yetterben

As we talked about plugs should be a light mocha color. I am glad i got yah up and running today. Now relocate that battery and take her for a mild test run. We can go from there on jetting depending on what your afr's are. I want you to take a passenger with you. Tell him what you're gonna do. Tell him something like this. " okay gonna run half throttle tell me what boost i hit and what air fuel ratio" so on and so forth. right it down. make all pulls in 3rd gear. 1st and 2nd are gonna go buy so fast its not even funny. remember buy the time you hear the buzzer the motor is probably all ready 1 grand past. Dont over rev that ******!

You are gonna have boost creep with that 3" exhaust keep an eye on that. You are gonna need to jet up for that. Sam can chime in and tell you what he put in the carb for jets and what he did when he went to 3"

john smack

iTrader: (12)

ok I did a couple runs it is lean all the way around it is 15's idling driving on primarys 14-16 under mid throttle slow boost 4psi it is unregistered on the guage it is just red
very lean but it did boost and it was kinda sweet I can feel the potential
when it is transitioning to secondaries it hesitates no matter how light you get into them

john smack

iTrader: (12)

It is so lean I dont hink I want to drive it again I suppose this means I need to re jet.......?

yetterben

I would think its either that or not enough fuel pressure up there did it **** and moan or drive good but was just lean!