External Wastegate on Stock Twins. For those who said it can't be done
Full Member
Joined: Jan 2013
Posts: 222
Likes: 0
From: Queensland
Wasn't ment to sound that way. Not dissin your work I think it's very good and will save money, I just couldn't see why you said they couldn't be sequential anymore after this mod. Sounded like if I was to proform this I had to go non sequential. Also there is more to this mod then just holding more then 18 psi. Cheap Dead internal wast gate repair. I like to try and keep my car as "stock"as I can if I can kill off the internal east gate and still stay sequential I will more than likely have a crack at it
Wasn't ment to sound that way. Not dissin your work I think it's very good and will save money, I just couldn't see why you said they couldn't be sequential anymore after this mod. Sounded like if I was to proform this I had to go non sequential. Also there is more to this mod then just holding more then 18 psi. Cheap Dead internal wast gate repair. I like to try and keep my car as "stock"as I can if I can kill off the internal east gate and still stay sequential I will more than likely have a crack at it
After thinking about, you might be able to do it, but you would have to remove the pre-spool actuator door and you could keep the main door in place that diverts most of the exhaust to the front turbo. Problem would be that without the pre-spool actuator and assembly in place you would have a longer transition between both turbos having full boost. It's a very interesting idea I'm going to have to think about.
I don't have a graph from this run but I do have a graph from when I made 470whp 400tq on a dynapak two weeks ago. Just for clarification the prior BNR non-sequential record was set on a Dynapak at 425whp. On this graph/run I had ignition breakup at high RPM due to me getting greedy with spark plug gap. I regaped my plugs before I made the run you see in the video above which solved the problem as you can see.
I chose to go non-sequential because the flapper doors limit the maximum power that can be made on the twins. The whole point of this build is to see how much power can be made using the stock frame turbos and using every exploit possible to extract that power.
As for "all you did really was port out a hole that was already there and blow a hole in a plate yes?" I think this doesn't give credence to the amount of time, work, and planning that went into doing this. This mod is something that has been talked about on this forum for over ten years with no one finding out a way to do it. Without this mod you cannot hold more then 18psi to redline and if you're running a wide open 3" exhaust you will also be dealing with boost creep problems at around 15psi.
If you don't understand the work that was done above then either you didn't read what I wrote, or you haven't been around the RX-7 world long enough do understand the problems that this fixes and the potential for more power it brings.
I chose to go non-sequential because the flapper doors limit the maximum power that can be made on the twins. The whole point of this build is to see how much power can be made using the stock frame turbos and using every exploit possible to extract that power.
As for "all you did really was port out a hole that was already there and blow a hole in a plate yes?" I think this doesn't give credence to the amount of time, work, and planning that went into doing this. This mod is something that has been talked about on this forum for over ten years with no one finding out a way to do it. Without this mod you cannot hold more then 18psi to redline and if you're running a wide open 3" exhaust you will also be dealing with boost creep problems at around 15psi.
If you don't understand the work that was done above then either you didn't read what I wrote, or you haven't been around the RX-7 world long enough do understand the problems that this fixes and the potential for more power it brings.
What do you use the car for if I may ask; Drag, Road Course etc etc?
Full Member
Joined: Jan 2013
Posts: 222
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From: Queensland
I have doubts to whether or not the pre spool door is needed on the stock system at all, well at lest on my s8 1st turbo is spooling from the Minute the car is started and all the boost is getting dumped till the stock valve closes . That doesn't seem to be till 2600rpm. Might be something messed up in my car
I use the car primarily as just a street car as it's more a experiment for me. I like pushing limits and doing what others say can't be done. Currently this setup is not viable long term as I'm sure my exhaust manifold absolute pressures are through the roof! That's why the torque is so high.
I still want to try to hit 500whp on the twins, might blow the motor trying, but knowing it can be done is worth it.
"the lag is really bad, but the power is delivered very progressively which allows for the car to have full traction in third gear"
That was my two weeks thoughts since i got the non -bnr 3's, lag is there but it's much better power delivery, power comes just enough for high RPM's to take care the rest of the power
on the sequential twins at third gear my car squeeks then gets the traction after (short period of sudden power then just dies off)
Even for track u get better corner on these u get to really step on it like non turbo LOL when i had sequential twins every corner i had to worry about sudden power delivery... somewhere in my mind
Also u don't hear your bov million times when driving long period of time XXXX these bov kicking on me everytime u let go the gas you wanna plug your ears after 3 hours of driving, on these non-s bnr's at second gear u gotta really step on it to hear your bov!!
I have some questions..
How are the lags and power deliver after all the work, respect on the numbers and work!
That was my two weeks thoughts since i got the non -bnr 3's, lag is there but it's much better power delivery, power comes just enough for high RPM's to take care the rest of the power
on the sequential twins at third gear my car squeeks then gets the traction after (short period of sudden power then just dies off)
Even for track u get better corner on these u get to really step on it like non turbo LOL when i had sequential twins every corner i had to worry about sudden power delivery... somewhere in my mind
Also u don't hear your bov million times when driving long period of time XXXX these bov kicking on me everytime u let go the gas you wanna plug your ears after 3 hours of driving, on these non-s bnr's at second gear u gotta really step on it to hear your bov!!
I have some questions..
How are the lags and power deliver after all the work, respect on the numbers and work!
Last edited by FD_virus85; May 31, 2013 at 05:07 AM.
No, never had the will to push it that far as the EGT's are high and I set the record; so I was planning on finally going single. That was until some Australian's decided that BNR's are crap and they can do better with hybrid twins. So I guess I'm in a new dick measuring contest.
No, never had the will to push it that far as the EGT's are high and I set the record; so I was planning on finally going single. That was until some Australian's decided that BNR's are crap and they can do better with hybrid twins. So I guess I'm in a new dick measuring contest.
Originally Posted by Zepticon
Only guy i have seen dissing the BNRs are the guy selling what he calls SP twins that he says he developed together with Hitachi?
I think that if you have to talk down a competitors (very good) product to be able to make your own look good, you dont have much of a product yourself. I was considering getting the SP twins, but when i asked about them i got a lot of hubris, which does not convince me. So im going with BNRs when i get to that 
Joined: Jul 2001
Posts: 10,672
Likes: 413
From: Charlottesville VA 22901
I love the innovation
However IMO you just ruined the only two advantages (internal wastegate and sequential) the twins have LOL
Wouldn't a t78 make about the same power with a similar curve at 15 to 17 psi?
However IMO you just ruined the only two advantages (internal wastegate and sequential) the twins have LOL
Wouldn't a t78 make about the same power with a similar curve at 15 to 17 psi?
_____________
Joined: Sep 2015
Posts: 140
Likes: 0
From: TEXAS
This is great. What size wastegates did you end up using? (sorry if i missed it).
I ran an External Gate on m 05 STi many years ago and yes, although it was loud (didnt have it plumbed back in the exhaust), the power delivery and boost control/ was much much better. Thats on one puny sized turbo.
The install is definitely not without its challenges from the pics, but still awesome work.
I ran an External Gate on m 05 STi many years ago and yes, although it was loud (didnt have it plumbed back in the exhaust), the power delivery and boost control/ was much much better. Thats on one puny sized turbo.
The install is definitely not without its challenges from the pics, but still awesome work.
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SAKEBOMB GARAGE LLC
www.SAKEBOMBGARAGE.com
Specialty aftermarket parts & service // Fremont, California
Contact: info@sakebombgarage.com
It's never fast enough...
Joined: Feb 2001
Posts: 3,760
Likes: 3
From: Miami - Given 1st place as the POOREST city in the US as per the federal government
Hey BJ, have you ever compared the 280hp fd exhaust manifold with the older ones to see if the potential for more flow is there?
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