12a BP Turbo options
Thread Starter
Joined: Nov 2006
Posts: 8,482
Likes: 31
From: Huntsville AL
12a BP Turbo options
Hey guys, looking at a turbo for my 12aBP.
Doing the math from the stickies, I am at 34.9lb/min.
Does a bridgeport flow more than that or would that be a good starting point?
The turbo I am looking for, I would like to have:
Internal Wastegate
Ball Bearings
Oil and Water cooled
Quick Spool
I am not looking for a massive number beast, if I am able to get 300whp out of this I will be very happy.
From what I can tell, I am looking at the BorgWarner EFR 6258 turbo. This has everything I am looking for, and the compressor map shows that I would be in the best range (from what I think I understand). This also says it has an "integrated BOV". I understand this means that it has a built-in blow off valve, but I just want to double check that if I were to get this turbo, I would NOT need to have a traditional blow off valve? I only want to run about 14-15PSI.
Specs on the engine:
12a Bridge port (standard, nothing huge)
Carter 4070 pump (72gph)
2.5l Surge tank
Walbro GSL392 In-Line fuel pump 255 LPH
EFI Hardware 55-53-50mm Tapered Throttle Body
Weber IDA intake manifold
MegaSquirt 2
Still have 4 injectors to buy, thinking of 4 700ishCC injectors? Still need to look up fuel flow math.
Another thing, there will be no intercooler. Plan on water injection pre-turbo, with meth injection immediately after the turbo. Still researching on parts lists and maths on how much CCs to use each to keep the temps at bay.
Doing the math from the stickies, I am at 34.9lb/min.
Does a bridgeport flow more than that or would that be a good starting point?
The turbo I am looking for, I would like to have:
Internal Wastegate
Ball Bearings
Oil and Water cooled
Quick Spool
I am not looking for a massive number beast, if I am able to get 300whp out of this I will be very happy.
From what I can tell, I am looking at the BorgWarner EFR 6258 turbo. This has everything I am looking for, and the compressor map shows that I would be in the best range (from what I think I understand). This also says it has an "integrated BOV". I understand this means that it has a built-in blow off valve, but I just want to double check that if I were to get this turbo, I would NOT need to have a traditional blow off valve? I only want to run about 14-15PSI.
Specs on the engine:
12a Bridge port (standard, nothing huge)
Carter 4070 pump (72gph)
2.5l Surge tank
Walbro GSL392 In-Line fuel pump 255 LPH
EFI Hardware 55-53-50mm Tapered Throttle Body
Weber IDA intake manifold
MegaSquirt 2
Still have 4 injectors to buy, thinking of 4 700ishCC injectors? Still need to look up fuel flow math.
Another thing, there will be no intercooler. Plan on water injection pre-turbo, with meth injection immediately after the turbo. Still researching on parts lists and maths on how much CCs to use each to keep the temps at bay.
Turbine wheel is way too small. Why do you have a BP if you only want 300whp?
The 7670 would be a better pick, but still slightly on the small side. I would use at least a 3.5" exhaust.
The 7670 would be a better pick, but still slightly on the small side. I would use at least a 3.5" exhaust.
Thread Starter
Joined: Nov 2006
Posts: 8,482
Likes: 31
From: Huntsville AL
Believe me, if I were to get 400WHP out of it, I would love it. I just fear overloading the tires in 4th/5th gear. Power is great when you can put it down. I don't want to end up like a 1000+HP Supra that can only do highway runs. I plan on having this as an every other weekend car, with some auto-x and track days scattered throughout.
Funny thing, I was just on your website
Thread Starter
Joined: Nov 2006
Posts: 8,482
Likes: 31
From: Huntsville AL
Never thought I would hear that!
With that turbo, the .83 would give me quicker spool, but it is single scroll. The .92 is twin scroll, I am understanding that even though it is a larger size, the twin scroll will spool quick enough to make the .83 not really an option. Is this correct? The V-Band clamp/flange option will obviously be taken.
It looks like this turbo will net me more than the 300ishWHP. I guess that is a good thing, this motor was built by another person (not a shop), so I assume the motor is stock (stock apex, no rotor mods, no oil mods, no windowed bearings, etc) besides the bridgeport and exhaust housing mods. While this motor churns the turbo, I have another 12a I will be building properly for higher RPM application. Current motor I am shifting at 7500RPM. Would it still have a quick spool? I am really looking for full boost around 3-3.5k.
Got a boroscope to check the ports but it seems like it only wants to focus at least 2 inches out...
With that turbo, the .83 would give me quicker spool, but it is single scroll. The .92 is twin scroll, I am understanding that even though it is a larger size, the twin scroll will spool quick enough to make the .83 not really an option. Is this correct? The V-Band clamp/flange option will obviously be taken.
It looks like this turbo will net me more than the 300ishWHP. I guess that is a good thing, this motor was built by another person (not a shop), so I assume the motor is stock (stock apex, no rotor mods, no oil mods, no windowed bearings, etc) besides the bridgeport and exhaust housing mods. While this motor churns the turbo, I have another 12a I will be building properly for higher RPM application. Current motor I am shifting at 7500RPM. Would it still have a quick spool? I am really looking for full boost around 3-3.5k.
Got a boroscope to check the ports but it seems like it only wants to focus at least 2 inches out...
Last edited by Jeezus; Apr 3, 2017 at 10:59 AM.
People who do these kinds of builds end up frustrated long term with the car because it's not livable. It ends up too loud, not enough low end torque, too much wrenching required, no traction, too smelly.
So OP can you clarify what you want this car to be? I am hearing conflicting goals.
You want quick spool, which often is what people usually say when they don't want to be constantly downshifting due to no torque under 4000rpm. You said you want no intercooler. Now the only reasons for that are transient response (floor it at 5000rpm, how long does it take to build boost) or packaging/fitment or maybe just cost. I'm guessing you want more perceived low end part load torque which has little to do with the size of the intercooler. Or maybe I'm wrong. Do you care about being able to go uphill in 5th gear without flooring it or downshifting?
Then you say you like the sound of a bridgeport. Ok, cool. But do you like it so much that you want to give up low end torque? Bridgeports aren't good for low end torque. The intake ports close too late.
Do you care about smell?
Do you care about noise? Like do you live in a suburban neighborhood and want to be able home at midnight in this car and not be concerned that you made the neighbors mad?
3.5" is better for performance but does OP care about how loud it is?
OP do you care about having a "normal" car? Like, could you hand the keys to a non car person and they could just drive it somewhere without any special instructions or explanations? If you do, then you need to go a different route. If you don't, you might want to rethink your ideas about caring about low end torque, and not wanting to make it a car that's focused on highway pulls.
So OP can you clarify what you want this car to be? I am hearing conflicting goals.
You want quick spool, which often is what people usually say when they don't want to be constantly downshifting due to no torque under 4000rpm. You said you want no intercooler. Now the only reasons for that are transient response (floor it at 5000rpm, how long does it take to build boost) or packaging/fitment or maybe just cost. I'm guessing you want more perceived low end part load torque which has little to do with the size of the intercooler. Or maybe I'm wrong. Do you care about being able to go uphill in 5th gear without flooring it or downshifting?
Then you say you like the sound of a bridgeport. Ok, cool. But do you like it so much that you want to give up low end torque? Bridgeports aren't good for low end torque. The intake ports close too late.
Do you care about noise? Like do you live in a suburban neighborhood and want to be able home at midnight in this car and not be concerned that you made the neighbors mad?
OP do you care about having a "normal" car? Like, could you hand the keys to a non car person and they could just drive it somewhere without any special instructions or explanations? If you do, then you need to go a different route. If you don't, you might want to rethink your ideas about caring about low end torque, and not wanting to make it a car that's focused on highway pulls.
Thread Starter
Joined: Nov 2006
Posts: 8,482
Likes: 31
From: Huntsville AL
People who do these kinds of builds end up frustrated long term with the car because it's not livable. It ends up too loud, not enough low end torque, too much wrenching required, no traction, too smelly.
So OP can you clarify what you want this car to be? I am hearing conflicting goals.
You want quick spool, which often is what people usually say when they don't want to be constantly downshifting due to no torque under 4000rpm. You said you want no intercooler. Now the only reasons for that are transient response (floor it at 5000rpm, how long does it take to build boost) or packaging/fitment or maybe just cost. I'm guessing you want more perceived low end part load torque which has little to do with the size of the intercooler. Or maybe I'm wrong. Do you care about being able to go uphill in 5th gear without flooring it or downshifting?
Then you say you like the sound of a bridgeport. Ok, cool. But do you like it so much that you want to give up low end torque? Bridgeports aren't good for low end torque. The intake ports close too late.
Do you care about smell?
Do you care about noise? Like do you live in a suburban neighborhood and want to be able home at midnight in this car and not be concerned that you made the neighbors mad?
3.5" is better for performance but does OP care about how loud it is?
OP do you care about having a "normal" car? Like, could you hand the keys to a non car person and they could just drive it somewhere without any special instructions or explanations? If you do, then you need to go a different route. If you don't, you might want to rethink your ideas about caring about low end torque, and not wanting to make it a car that's focused on highway pulls.
So OP can you clarify what you want this car to be? I am hearing conflicting goals.
You want quick spool, which often is what people usually say when they don't want to be constantly downshifting due to no torque under 4000rpm. You said you want no intercooler. Now the only reasons for that are transient response (floor it at 5000rpm, how long does it take to build boost) or packaging/fitment or maybe just cost. I'm guessing you want more perceived low end part load torque which has little to do with the size of the intercooler. Or maybe I'm wrong. Do you care about being able to go uphill in 5th gear without flooring it or downshifting?
Then you say you like the sound of a bridgeport. Ok, cool. But do you like it so much that you want to give up low end torque? Bridgeports aren't good for low end torque. The intake ports close too late.
Do you care about smell?
Do you care about noise? Like do you live in a suburban neighborhood and want to be able home at midnight in this car and not be concerned that you made the neighbors mad?
3.5" is better for performance but does OP care about how loud it is?
OP do you care about having a "normal" car? Like, could you hand the keys to a non car person and they could just drive it somewhere without any special instructions or explanations? If you do, then you need to go a different route. If you don't, you might want to rethink your ideas about caring about low end torque, and not wanting to make it a car that's focused on highway pulls.
I have learned from past mistakes, believe me. I have an FB that has been down for 5+ years now because wiring and brake frustration, plus not having access to actually working on it to fix these problems. Now that I have my own home, that is moot. With that said:
A weekend car. A car I take out because it is a Sunday and everyone is out of church. Cruise to my grandmothers house and she know's I am there before I ring the bell.
Honestly, I have a Protege that is my daily driver, and a miata that is my drop-top weekend fun car. My RX7 isn't gonna be a third wheel, but just another option.
Do I care about downshifting? No. It is what makes owning a manual fun
Do I care about smell? No. That is for the guy behind me when I premix a little too much.
Do I care about sound? No. 3 inch, 4 inch, or even 5 inch exhaust will not bother me if that is what will keep boost creep or lag at bay. I am hoping 3.5 should be enough. I can make my own mufflers.
I can tailor my cars to my needs, if I am going to get home or the possibility of getting home too late, I drive the miata. I feel no need for having to HAVE 300+hp to go to a friends house.
Driving this car will be nothing more than a treat for me, to know that all the work I do and hardships I have to put up with, I can buckle up in my 79LE and smile.
Hope that half rant answered some questions
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Never thought I would hear that!
With that turbo, the .83 would give me quicker spool, but it is single scroll. The .92 is twin scroll, I am understanding that even though it is a larger size, the twin scroll will spool quick enough to make the .83 not really an option. Is this correct? The V-Band clamp/flange option will obviously be taken.
It looks like this turbo will net me more than the 300ishWHP. I guess that is a good thing, this motor was built by another person (not a shop), so I assume the motor is stock (stock apex, no rotor mods, no oil mods, no windowed bearings, etc) besides the bridgeport and exhaust housing mods. While this motor churns the turbo, I have another 12a I will be building properly for higher RPM application. Current motor I am shifting at 7500RPM. Would it still have a quick spool? I am really looking for full boost around 3-3.5k.
Got a boroscope to check the ports but it seems like it only wants to focus at least 2 inches out...
With that turbo, the .83 would give me quicker spool, but it is single scroll. The .92 is twin scroll, I am understanding that even though it is a larger size, the twin scroll will spool quick enough to make the .83 not really an option. Is this correct? The V-Band clamp/flange option will obviously be taken.
It looks like this turbo will net me more than the 300ishWHP. I guess that is a good thing, this motor was built by another person (not a shop), so I assume the motor is stock (stock apex, no rotor mods, no oil mods, no windowed bearings, etc) besides the bridgeport and exhaust housing mods. While this motor churns the turbo, I have another 12a I will be building properly for higher RPM application. Current motor I am shifting at 7500RPM. Would it still have a quick spool? I am really looking for full boost around 3-3.5k.
Got a boroscope to check the ports but it seems like it only wants to focus at least 2 inches out...
Is it a turbo bridgeport? Should have no trouble getting on boost and spooling up if it is.
Thread Starter
Joined: Nov 2006
Posts: 8,482
Likes: 31
From: Huntsville AL
I am having a hard time getting diagrams on this turbo. I want to build a mock up of it so I know where everything would line up...
BW have some fairly detailed diagrams on their website;
Performance Turbos | BorgWarner Turbo Systems
Performance Turbos | BorgWarner Turbo Systems
Thread Starter
Joined: Nov 2006
Posts: 8,482
Likes: 31
From: Huntsville AL
BW have some fairly detailed diagrams on their website;
Performance Turbos | BorgWarner Turbo Systems
Performance Turbos | BorgWarner Turbo Systems
There are enough measurements there to use a scale ruler or whatever to get the rest, but i personally wouldn't be comfortable putting that much time and effort into fabrication without having the actual turbo.
Basic handy man stuff- you can just scale it off the screen with some calipers or a ruler.
For instance on the EFR 8374 it shows a 2.50" for the compressor outlet.
If I measure that at 2.00" on the screen (the larger you make it the more accurate) I can use this 2.00/2.50 scale to figure out the size of anything on the turbo I measure on the picture.
Cross multiply and divide when dealing with ratios.
That is how I figured it out for my EFR set-up.
-edit- beat to the punch on posting
For instance on the EFR 8374 it shows a 2.50" for the compressor outlet.
If I measure that at 2.00" on the screen (the larger you make it the more accurate) I can use this 2.00/2.50 scale to figure out the size of anything on the turbo I measure on the picture.
Cross multiply and divide when dealing with ratios.
That is how I figured it out for my EFR set-up.
-edit- beat to the punch on posting