Qbuilt

Hey all,
So I have pretty much finished up putting a turbo on my 12a. However after going for a few little drives i know i have a couple bugs to work ouy. First off my setup is stockport 12a, weber 45dcoe sidedraft with custom carb hat with racing beat intake, custom turbo spacer and s4 manifold/turbo, msd 6a, blaster coils, b9es plugs. Aeromotive 1:1 regulater, holley efi 190 gph pump, 3/8 fuel lines for feed and return. I have a egt guage and wideband, just need to install. I dont have an intercooler if anyone is wondering. I have my blow off valve hooked to a splice from my brake boosterline as i didnt want to remove the intake to drill and tap it for a port. Does that sound O.k. Or do you even need vacumn to the blowoff valve?
I know the weber needs to be tuned. As of now i have f-11 etubes, 155 air correctors, 170 main jets, 45 pump squirters, 60f9 idle jets. It idles great and feels pretty good at cruise but i have a flat spot/stumble right of idle and it flat spots/bogs/lean spot when going to a moderate throttle opening. Then if backfires and pops at any sort of full throttle attmept. If i roll onto the throttle slowy it usually is ok. That usually sorts it self out a little after a few second and then the power comes on but it definetly feels weak. But i suppose the wideband will tell me if this is due to being too lean or to rich. Or could it be ignition related? I try to stay out of boost as much as possible untill i get the wideband in and i can tune somemore drivabilitly into the car. Also ive been playing with timing and wanted to avoid locking my distributor. I have it set for total timing of 15 deg advanced with a 10 deg split and the vacumn advance still hooked so it idles much better. However i have a concern with the spark plugs that i was recommended. I found i cant get my socket on them once they are bottomed out. The eyebrows on the block over the sparkplug holes prevent this. I had to tighten them gently with a rag on the ceramic. Can i just shave my socket down to fit or is there a better part number in a 9 or 10 heat range that will work better??
Anyways just wanted to let you know that there is another 12a turbo on the road and would love to hear all your suggestions and opinions.
I also want to thank everybody who has given me suggestions in the past and all the others who have done this before me. Ive learned so much from them.
Thanks again.

perfect_circle

congrats man, post up some pics, and get it tuned!

83rx7boy92

how well to stock 12a motors hold up to boost? do they blow up easy?

Qbuilt

Thanks,
Oh i forgot to mention my turbo( i think?) is making a supercharger type noise. It wasnt doing this earlier but now i can hear it wind up really loud and it doesnt sound good or normal. What do you guys think, do i have a leak or something? It still makes boost and comes on great.

cmanns

bearings or w/e making more noise then normal is a good guess?

allso just take what i said into consideration i dont know ANYTHING bout turbo's or 12a's to a extent so i'm just throwing that out there

84stock

iTrader: (5)

Like to know how yours works out. How fresh is your engine. I have a T3 turbo (actually 2 of them, 1 for each of my 7's) that i will be installing through the winter. First will go on my stock 12a, total budget setup, custom intake I modified myself followed by what will be a custom turbo exhaust manifold. Turbos are off a Tbird turbo coupe.

680RWHP12A

when the turbo makes noise its a sign the turbo is out of balance.. it will work fine like that for quite a while

if the popping bogging is happening during your transition from idle to main circut()try bigger idle jets) or your accelerator pump jet is not big enough, it should be a 0 bypass(no hole on the side of the jet if there is no number on it and its located in the bottom of the float bowl)

also what ignition setup are you running? try gapping the plug gap down to .015.. if your ignition is weak it could be putting the spark out when the boost initally hits..

680RWHP12A

the turbo off a t bird coupe is wayyy too small for a rotary, the turbine side will choke the motor killing most h/p gains.. go with a stock turbo 2 turbo for good results

Qbuilt

Im running an msd 6a and blaster coils, and my plugs are gapped to .015. So maybe the backfireing is due to the carb tune??
The turbo noise is weird because the first time i drove the car i had the blowoff valve hooked to the carb hat( so it only saw boost, im dumb) but it still made a whooosh sound when shifting, however the turbo was dead quiet. It wasnt untill i drove the car the second time that the sound started.

680RWHP12A

yah, check the carb tune, start with the stuff i suggested first.
also you can run trailing t2 plugs(9 heat range) so you can use a regular spark plug socket...

perfect_circle

the blow off valve is supposed to have a boosetd source. becuase it vents when it sees a massive increase in pressure.

680RWHP12A

nope,bov is supposed too see vacuem to open,(wich it wont see at the carb hat) if a boost spike opens the bov then that would mean it would leak at higher boost levels=not good

perfect_circle

how does it vent if it sees vacuum? because when you shift, you let off the throttle, closing the throttle plates, and since the turbo is still creating boost, it makes alot of pressure. isnt that were the BOV gets it signal? or is it from the intake manifold. like after the throttle plate close?

Qbuilt

yah, check the carb tune, start with the stuff i suggested first.
also you can run trailing t2 plugs(9 heat range) so you can use a regular spark plug socket...

Do you mean like stock Rx7 87 turbo II plugs. I can use these for my leading and trailing??

Dan_s_young

iTrader: (1)

Hey man, Good to see you are having luck with your setup! My guess is once you get the wideband you will be able to work out alot of your problems. I know with that carb I had a bunch of tuning problems, but thats because I was making jetting guesses.

We will have to go for a cruise or something once my car is on the road (its still got a ways to go...). Can't wait to see pictures of your setup!

13BTOY

iTrader: (1)

Yes stock trailing plugs(9's) for the L and T.
Youre blow off valve should be getting its signal from the manifold for it to function properly. Whats your baseline fuel pressure set at?

Ed

84stock

iTrader: (5)

The one I have is the larger set up, it a T3. The newer coupes only had a tiny turbo for quick spool. The same turbo sustained 18lbs boost on a mustang 2.3L without falling off and ran 13.5 in the quarter with a 35 shot of NOS

84stock

iTrader: (5)

Besides, it's only going on a stockport 12a.

84stock

iTrader: (5)

The T3 is about the same or bigger that the 12at turbo producing 146hp. Just to keep things straight, I have a GSL SE with a ported 13b, Camden s/c, water methanol injection, choice of 3 carbs depending on what I wanna do with it and likely nitrous this winter. No the GS has 170,000 km, is in decent shape (interior is near perfect), cost me only $500 to buy and put $500 in it in minor stuff and minor rust repair and repaint. The turbo cost me $100 complete with factory wastegate, the manifod will be custom made for about $150, I already have a custom fabbed 12a intake that will accept my Edelbrock & K&N carb hat and will watch the junkyard for a suitable intercooler (volvo, etc). So even with the intercooled turbo I'll only be into this car for about $1500 and hope to see about 130 rwhp without going past 7000rpm on a frugal budget.

Qbuilt

My fuel pressure is at 4-5 psi. It seems pretty good at this psi and when i rev the car up i can see the pressure rising due to the rrfpr.

84stock

iTrader: (5)

I would suggest an upgraded fuel pump and a rising rate fuel pressure regulator if you end up making some good power.

Qbuilt

I already have a good fuel system. I have a efi 190 gph pump and an aeromotive rising rate regulator. Plus 3/8 fuel lines for minimal restriciton.
I just put in some big main jets. Approx 210 maybe. So im sure im running a bit on the rich side, but man it hauled ***. If i punched it in first it would spin all the way till i shifted then i would spin most way thru second. I think this might be a little to fun, I cant wait till im all tuned up.