Questions for a turbo 12A build
04-22-11, 11:12 AM
#1
Questions for a turbo 12A build
Howdy,
I've been doing my best to read up on as much as I can on this, so I'll keep my questions short and try not to make them stupid. I've read up on here:
http://www.turbofb.com/interchangefaq.htm
https://www.rx7club.com/showthread.p...pr+intercooler
https://www.rx7club.com/1st-gen-archive-71/engine-12a-turbo-write-up-116768/
And of course, Bad 83's thread.
My plan of action is:
1984 GSL, currently stock.
Onto the plan.
NPR short inercooler mounted infront of the radiator.
S5 turbo and manifold
Oil lines/feed lines
Racing Beat oil filter block
Remove all emissions
2.5" intercooler pipes + bov
Racing Beat Downpipe
Carb Hat
Boost prepped Nikki
Locked Dizzy
Mallory 4309 FPR
Walbro 255LPH
Will check the lines to see what should and what shouldn't be replaced
Misc stuff like air filter, clamps, filters, fluids, connections for coolant
My questions:
Does anyone have pictures of their "spacers" for the turbo manifold? I don't have any experience welding, but according to Bad 83's thread, it's just a 1.125" spacer. I'd just like pictures for reference. Is it that hard to clear the intake manifold.
Other then Rotary Shack, is there any other place to get a carb hat?
How do you guys seem to tune without a wideband?
I know this is kinda n00bish, but I'm try to learn a few things
.
Thanks guys,
Christopher
I've been doing my best to read up on as much as I can on this, so I'll keep my questions short and try not to make them stupid. I've read up on here:
http://www.turbofb.com/interchangefaq.htm
https://www.rx7club.com/showthread.p...pr+intercooler
https://www.rx7club.com/1st-gen-archive-71/engine-12a-turbo-write-up-116768/
And of course, Bad 83's thread.
My plan of action is:
1984 GSL, currently stock.
Onto the plan.
NPR short inercooler mounted infront of the radiator.
S5 turbo and manifold
Oil lines/feed lines
Racing Beat oil filter block
Remove all emissions
2.5" intercooler pipes + bov
Racing Beat Downpipe
Carb Hat
Boost prepped Nikki
Locked Dizzy
Mallory 4309 FPR
Walbro 255LPH
Will check the lines to see what should and what shouldn't be replaced
Misc stuff like air filter, clamps, filters, fluids, connections for coolant
My questions:
Does anyone have pictures of their "spacers" for the turbo manifold? I don't have any experience welding, but according to Bad 83's thread, it's just a 1.125" spacer. I'd just like pictures for reference. Is it that hard to clear the intake manifold.
Other then Rotary Shack, is there any other place to get a carb hat?
How do you guys seem to tune without a wideband?
I know this is kinda n00bish, but I'm try to learn a few things
.Thanks guys,
Christopher
04-22-11, 10:19 PM
#3
Thanks,
I'm looking for a way to pretty much copy Bad 83's first build. Just something simple and reliable (as far as a turbocharged car goes), just trying to figure out of the turbo aspect and trying to see what people did for spacers for the turbo manifold.
I'm looking for a way to pretty much copy Bad 83's first build. Just something simple and reliable (as far as a turbocharged car goes), just trying to figure out of the turbo aspect and trying to see what people did for spacers for the turbo manifold.
04-22-11, 11:19 PM
#4
83fbgsl
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I did a 12a turbo build,chopped up a racing beat header and welded a flange,clearance was tight around the idler arm(need a shield), just a suggestion T-3 turbo intake 60,exhaust 48 ,= full boost around 2k rpm-hope this helps
04-22-11, 11:26 PM
#5
Check this thread too...its one of my favorite 12a turbo builds...
https://www.rx7club.com/old-school-other-rotary-63/rx2-sedan-12a-turbo-project-928917/
https://www.rx7club.com/old-school-other-rotary-63/rx2-sedan-12a-turbo-project-928917/
04-23-11, 11:53 AM
#7
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Take it from someone with a blow-through Weber setup: don't do it. While I love Webers on NA engines, they are a PITA to get tuned on a boosted one, especially if you have a small, fast-spooling turbo like mine. My next blow-through engine will have a boost-prepped Nikki. The Weber may flow better and be easier to boost-prep, but I expect the Nikki to be far more drivable.
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04-23-11, 03:13 PM
#9
Take it from someone with a blow-through Weber setup: don't do it. While I love Webers on NA engines, they are a PITA to get tuned on a boosted one, especially if you have a small, fast-spooling turbo like mine. My next blow-through engine will have a boost-prepped Nikki. The Weber may flow better and be easier to boost-prep, but I expect the Nikki to be far more drivable.
Currently have an intercooler, turbo, and such, was waiting to buy a FPR and such before I really started to tear into the project.
04-24-11, 10:44 AM
#12
Take it from someone with a blow-through Weber setup: don't do it. While I love Webers on NA engines, they are a PITA to get tuned on a boosted one, especially if you have a small, fast-spooling turbo like mine. My next blow-through engine will have a boost-prepped Nikki. The Weber may flow better and be easier to boost-prep, but I expect the Nikki to be far more drivable.
On a nikki you'll have to remove the carb hat and partial disassemble the air horn just to change a jet.... that sounds WAY easier, right?
Just because you've had difficulty tuning your set-up doesn't mean it's a bad set-up...
04-24-11, 12:08 PM
#13
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No, that's not at all what I meant. The jets are easy to get to, yes. The TUNING is what's a PITA.
You think the idle-main transition is tricky to get right for an NA engine? Things get real interesting when you add boost to the equation. If I use an e-tube that gets me down into the low 12s to high 11s at WOT when I hit full boost (about 3000 RPM), I get very poor cruise drivability and terrible gas mileage on the freeway. If I tune out the drivability problems, it's way too lean in certain parts of the rev range unless I use a stupidly huge idle jet, which just introduces drivability problems in the low RPM range instead. My current solution is to run too lean and pull a lot of timing, which hurts both power and gas mileage. Plus, Weber doesn't make an AP jet big enough for me. I'm using 70s now, and to tune out the stumble completely I'll have to drill my own. Additionally, Webers have tiny fuel inlets, which becomes problematic very quickly the more power you're trying to make.
Been there, done that, won't do it again.
You think the idle-main transition is tricky to get right for an NA engine? Things get real interesting when you add boost to the equation. If I use an e-tube that gets me down into the low 12s to high 11s at WOT when I hit full boost (about 3000 RPM), I get very poor cruise drivability and terrible gas mileage on the freeway. If I tune out the drivability problems, it's way too lean in certain parts of the rev range unless I use a stupidly huge idle jet, which just introduces drivability problems in the low RPM range instead. My current solution is to run too lean and pull a lot of timing, which hurts both power and gas mileage. Plus, Weber doesn't make an AP jet big enough for me. I'm using 70s now, and to tune out the stumble completely I'll have to drill my own. Additionally, Webers have tiny fuel inlets, which becomes problematic very quickly the more power you're trying to make.
Been there, done that, won't do it again.
04-24-11, 07:02 PM
#14
Got it, seems that doing an OER or sidedraft isn't it.
Nikki for me!
Anyone have pictures of their turbo manifold/spacers by any chance? Trying to get ideas, I did fine that Rene @ RotaryWorks is still making these for $250 a peice, was just seeing the options for manifolds. I do like the spacer idea for use of the RB downpipe.
Nikki for me!
Anyone have pictures of their turbo manifold/spacers by any chance? Trying to get ideas, I did fine that Rene @ RotaryWorks is still making these for $250 a peice, was just seeing the options for manifolds. I do like the spacer idea for use of the RB downpipe.
04-24-11, 09:07 PM
#15
No, that's not at all what I meant. The jets are easy to get to, yes. The TUNING is what's a PITA.
You think the idle-main transition is tricky to get right for an NA engine? Things get real interesting when you add boost to the equation. If I use an e-tube that gets me down into the low 12s to high 11s at WOT when I hit full boost (about 3000 RPM), I get very poor cruise drivability and terrible gas mileage on the freeway. If I tune out the drivability problems, it's way too lean in certain parts of the rev range unless I use a stupidly huge idle jet, which just introduces drivability problems in the low RPM range instead. My current solution is to run too lean and pull a lot of timing, which hurts both power and gas mileage. Plus, Weber doesn't make an AP jet big enough for me. I'm using 70s now, and to tune out the stumble completely I'll have to drill my own. Additionally, Webers have tiny fuel inlets, which becomes problematic very quickly the more power you're trying to make.
Been there, done that, won't do it again.
You think the idle-main transition is tricky to get right for an NA engine? Things get real interesting when you add boost to the equation. If I use an e-tube that gets me down into the low 12s to high 11s at WOT when I hit full boost (about 3000 RPM), I get very poor cruise drivability and terrible gas mileage on the freeway. If I tune out the drivability problems, it's way too lean in certain parts of the rev range unless I use a stupidly huge idle jet, which just introduces drivability problems in the low RPM range instead. My current solution is to run too lean and pull a lot of timing, which hurts both power and gas mileage. Plus, Weber doesn't make an AP jet big enough for me. I'm using 70s now, and to tune out the stumble completely I'll have to drill my own. Additionally, Webers have tiny fuel inlets, which becomes problematic very quickly the more power you're trying to make.
Been there, done that, won't do it again.
Tuning a carb is still tuning a carb no matter what the set-up. It's always about compromise, if you want complete control then go with EFI, trust me I tune cars for a living. As for the problems you're having..... 2 easy fixes.
For the tiny fuel inlets...run a -6 fuel inlet.... running a weber you can get a 3.0 needle as well... no more fueling issues. Also, make sure that you are feeding the vacuum for your FPR from both rotor housings... i have two 1/8" vacuum nipples that tee together and feed my FPR.
As for AP jets.... pull them out. You will still get an acellerator shot, but no restrictions. Then you don't have to worry as much about perfect idle-main transition.
04-24-11, 11:05 PM
#16
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As for the problems you're having..... 2 easy fixes.
For the tiny fuel inlets...run a -6 fuel inlet.... running a weber you can get a 3.0 needle as well... no more fueling issues. Also, make sure that you are feeding the vacuum for your FPR from both rotor housings... i have two 1/8" vacuum nipples that tee together and feed my FPR.
As for AP jets.... pull them out. You will still get an acellerator shot, but no restrictions. Then you don't have to worry as much about perfect idle-main transition.
For the tiny fuel inlets...run a -6 fuel inlet.... running a weber you can get a 3.0 needle as well... no more fueling issues. Also, make sure that you are feeding the vacuum for your FPR from both rotor housings... i have two 1/8" vacuum nipples that tee together and feed my FPR.
As for AP jets.... pull them out. You will still get an acellerator shot, but no restrictions. Then you don't have to worry as much about perfect idle-main transition.
And at this point I'm just tired of messing with it anyway. Jets get expensive really quick and in the end it will still be worse than even a very basic EFI tune. But that's not what this thread is about.
04-25-11, 09:35 AM
#17
Thanks for all the help everyone, been reading this thread alot too:
https://www.rx7club.com/forum/showth...anifold&page=2
Also, Bad 83 has been a great help in getting me in the direction of prepping my carb/locking the dizzy.
https://www.rx7club.com/forum/showth...anifold&page=2
Also, Bad 83 has been a great help in getting me in the direction of prepping my carb/locking the dizzy.
10-16-11, 03:04 PM
#21
You have to make it or have someone make it. You can buy the 12a and 13b flanges from Racing Beat and weld pipes in between. From what I read in that thread Jager posted pics from, it's a lot of work getting it to fit just right. Has to go out far enough to clear the intake manifold, but not too far or too low or it will contact the strut tower and the idler arm. So I'm thinking of just having an entire manifold built.
Jager, I saw you were selling the car... did you give up on the build?
Jager, I saw you were selling the car... did you give up on the build?
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