External Wastegate on Stock Twins. For those who said it can't be done - Page 2 - RX7Club.com - Mazda RX7 Forum

Go Back  RX7Club.com - Mazda RX7 Forum > Generation Specific > 3rd Generation Specific (1993-2002)
Reload this Page >

External Wastegate on Stock Twins. For those who said it can't be done

3rd Generation Specific (1993-2002) 1993-2002 Discussion including performance modifications and Technical Support Sections.

External Wastegate on Stock Twins. For those who said it can't be done

Old 05-27-13, 02:51 PM
  #26  
Full Member
 
Join Date: Jan 2013
Location: Queensland
Posts: 220
Thanks: 0
Thanked 0 Times in 0 Posts
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
Mps_hell is offline  
Old 05-27-13, 05:48 PM
  #27  
Turbo Lover
10 Year Member
Thread Starter
iTrader: (6)
 
Ball joint's Avatar
 
Join Date: Mar 2003
Location: Cleveland
Posts: 784
Thanks: 0
Thanked 0 Times in 0 Posts
Originally Posted by Mps_hell View Post
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
It's all good and thanks for the compliments, I guess I took it the wrong way as well.

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.
Ball joint is offline  
Old 05-27-13, 06:24 PM
  #28  
Torqueless Wonder
10 Year Member
iTrader: (1)
 
cptpain's Avatar
 
Join Date: Oct 2004
Location: Killeen, Texas, U.S.A.
Posts: 2,018
Thanks: 0
Thanked 0 Times in 0 Posts
Originally Posted by Ball joint View Post
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.
Thats a nice graph. Very progresssive.

What do you use the car for if I may ask; Drag, Road Course etc etc?
cptpain is offline  
Old 05-27-13, 07:18 PM
  #29  
Full Member
 
Join Date: Jan 2013
Location: Queensland
Posts: 220
Thanks: 0
Thanked 0 Times in 0 Posts
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
Mps_hell is offline  
Old 05-27-13, 08:51 PM
  #30  
Turbo Lover
10 Year Member
Thread Starter
iTrader: (6)
 
Ball joint's Avatar
 
Join Date: Mar 2003
Location: Cleveland
Posts: 784
Thanks: 0
Thanked 0 Times in 0 Posts
Originally Posted by cptpain View Post
Thats a nice graph. Very progresssive.

What do you use the car for if I may ask; Drag, Road Course etc etc?
Thanks for the compliments! It's one of the reasons's why I've always liked non-sequential twins, the lag is really bad, but the power is delivered very progressively which allows for the car to have full traction in third gear. I've been in single turbo car's that make less power but rip tire in third because of how the power comes on all within 500rpm. Second gear is still usable but it rips the tires loose pretty bad.

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.
Ball joint is offline  
Old 05-28-13, 04:14 PM
  #31  
Full Member
iTrader: (26)
 
Join Date: Mar 2012
Location: Savannah, GA
Posts: 103
Thanks: 0
Thanked 0 Times in 0 Posts
I would love to see this mod in a more detailed how-to guide. Good luck in hitting 500.
OverEzzz is offline  
Old 05-31-13, 04:18 AM
  #32  
Full Member
5 Year Member
 
Lock & Load's Avatar
 
Join Date: Jan 2007
Location: AUSTRALIA
Posts: 72
Thanks: 0
Thanked 0 Times in 0 Posts
Great effort keep us posted
Lock & Load is offline  
Old 05-31-13, 05:43 AM
  #33  
Senior Member
iTrader: (10)
 
FD_virus85's Avatar
 
Join Date: Oct 2009
Location: :+:Toronto:+:
Posts: 726
Thanked 0 Times in 0 Posts
"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!

Last edited by FD_virus85; 05-31-13 at 06:07 AM.
FD_virus85 is offline  
Old 07-16-13, 08:33 AM
  #34  
sold--no longer in debt
 
cloead's Avatar
 
Join Date: Dec 2002
Location: Cleveland, Ohio
Posts: 1,648
Thanked 8 Times in 2 Posts
THIS IS SOME CRAZY STUFFc
cloead is offline  
Old 07-24-13, 12:44 AM
  #35  
RX 4BPT
 
Join Date: Feb 2011
Location: Huddersfield, England
Posts: 290
Thanks: 0
Thanked 0 Times in 0 Posts
Any results on this yet?
Grant M is offline  
Old 08-06-13, 02:12 AM
  #36  
Senior Member
iTrader: (5)
 
Join Date: Dec 2011
Location: iowa city
Posts: 310
Thanks: 0
Thanked 0 Times in 0 Posts
You are my hero ball joint. great job on the mod
edgars95rx7 is offline  
Old 03-19-16, 02:16 PM
  #37  
RX 4BPT
 
Join Date: Feb 2011
Location: Huddersfield, England
Posts: 290
Thanks: 0
Thanked 0 Times in 0 Posts
Did you ever make 500hp?
Grant M is offline  
Old 09-03-16, 07:05 PM
  #38  
Turbo Lover
10 Year Member
Thread Starter
iTrader: (6)
 
Ball joint's Avatar
 
Join Date: Mar 2003
Location: Cleveland
Posts: 784
Thanks: 0
Thanked 0 Times in 0 Posts
Originally Posted by Grant M View Post
Did you ever make 500hp?
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.
Ball joint is offline  
Old 09-03-16, 08:28 PM
  #39  
OEM
iTrader: (1)
 
Zepticon's Avatar
 
Join Date: Jul 2012
Location: Norway
Posts: 548
Thanked 63 Times in 43 Posts
Originally Posted by Ball joint View Post
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.
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?
Zepticon is offline  
Old 09-03-16, 09:18 PM
  #40  
Rotary Enthusiast
iTrader: (8)
 
DC5Daniel's Avatar
 
Join Date: Jul 2012
Location: GA
Posts: 1,299
Thanks: 0
Thanked 5 Times in 4 Posts
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?
Ding ding ding
DC5Daniel is offline  
Old 09-04-16, 03:14 PM
  #41  
OEM
iTrader: (1)
 
Zepticon's Avatar
 
Join Date: Jul 2012
Location: Norway
Posts: 548
Thanked 63 Times in 43 Posts
Originally Posted by DC5Daniel View Post
Ding ding ding
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
Zepticon is offline  
Old 09-13-16, 08:13 PM
  #42  
It's never fast enough...
 
Flybye's Avatar
 
Join Date: Feb 2001
Location: Miami - Given 1st place as the POOREST city in the US as per the federal government
Posts: 3,752
Thanks: 0
Thanked 0 Times in 0 Posts
Buy old manifolds, modify, make a group buy, just sayin.

Anyways nice job!
Flybye is offline  
Old 10-17-16, 07:59 AM
  #43  
Put it in the microwave!
iTrader: (20)
 
kensin's Avatar
 
Join Date: Jul 2009
Location: CA
Posts: 1,400
Thanked 18 Times in 17 Posts
I'll send you my manifold and money lol
kensin is offline  
Old 10-17-16, 01:13 PM
  #44  
All out Track Freak!
iTrader: (259)
 
Fritz Flynn's Avatar
 
Join Date: Jul 2001
Location: Charlottesville VA 22901
Posts: 10,153
Thanked 68 Times in 58 Posts
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?
Fritz Flynn is offline  
Old 10-17-16, 04:48 PM
  #45  
_____________
 
borisf's Avatar
 
Join Date: Sep 2015
Location: Connecticut
Posts: 143
Thanked 0 Times in 0 Posts
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.
borisf is offline  
Old 11-04-16, 04:46 PM
  #46  
www.SakeBombGarage.com
RX7Club Vendor
iTrader: (17)
 
SakeBomb Garage's Avatar
 
Join Date: Jan 2011
Location: California
Posts: 1,829
Thanked 50 Times in 32 Posts
Originally Posted by Fritz Flynn View Post
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?
When I first read the thread I was hoping it would be a solution for an external gate on sequential twins. Non-Sec twins have all of the disadvantages (IMO) of sequential twins (huge lump of glowing iron on the side of the motor and compromised exhaust flow paths) and few advantages besides cost. It's cool to see someone innovating though!
__________________
SAKEBOMB GARAGE LLC
www.SAKEBOMBGARAGE.com
Specialty aftermarket parts & service // Fremont, California
Contact: [email protected]
SakeBomb Garage is offline  
Old 11-05-16, 01:45 AM
  #47  
Full Member
 
RX7Zamboni's Avatar
 
Join Date: Nov 2011
Location: NY
Posts: 206
Thanked 0 Times in 0 Posts
Someone's gata figure out how to do this but stay sequential
RX7Zamboni is offline  
Old 11-05-16, 06:39 AM
  #48  
It's never fast enough...
 
Flybye's Avatar
 
Join Date: Feb 2001
Location: Miami - Given 1st place as the POOREST city in the US as per the federal government
Posts: 3,752
Thanks: 0
Thanked 0 Times in 0 Posts
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?
Flybye is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
C. Ludwig
Single Turbo RX-7's
49
01-30-19 07:31 AM
Skeese
Adaptronic Engine Mgmt - AUS
65
03-28-17 04:30 PM
befarrer
Microtech
3
08-22-15 06:52 PM


Thread Tools
Search this Thread
Quick Reply: External Wastegate on Stock Twins. For those who said it can't be done


Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.