half bridge on stock twin turbos
#1
Junior Member
Thread Starter
Join Date: Nov 2013
Location: west auckland
Posts: 12
Likes: 0
Received 0 Likes
on
0 Posts
half bridge on stock twin turbos
hi guys i have a fd3s s7 rx7 and am wondering if its possible to run a half bridgeport on the stock twin turbos, which are non sequential. emissions have also been removed, and will be run with a power fc ecu. is this safely do-able
#3
Moderator
iTrader: (3)
since they will obviously physically bolt up to the engine they came with, then yes, it CAN be done. the real question is why? even with a half-bridge, you will still have too much engine for the turbos - and not just a little either, it will be a gross mismatch.
reconsider or explain what it is you're trying to do and get better advice.
reconsider or explain what it is you're trying to do and get better advice.
#5
Rotary Motoring
iTrader: (9)
Seems like PARALLEL stock twins on a half bridge would suit it ok if you are looking for ~300-350hp max.
In parallel configuration you actually get a lot of hotside area, so it shouldn't choke out the bridge on the low rpm too badly.
Downside is parallel twins are really really laggy.
I mean a stock sequential FD with exhaust/intake/IC/boost up (~300hp) would absolutely rape it.
50hp up top (and requiring supporting mods) isn't worth losing 100hp down low in my opinion.
In parallel configuration you actually get a lot of hotside area, so it shouldn't choke out the bridge on the low rpm too badly.
Downside is parallel twins are really really laggy.
I mean a stock sequential FD with exhaust/intake/IC/boost up (~300hp) would absolutely rape it.
50hp up top (and requiring supporting mods) isn't worth losing 100hp down low in my opinion.
#6
Junior Member
Thread Starter
Join Date: Nov 2013
Location: west auckland
Posts: 12
Likes: 0
Received 0 Likes
on
0 Posts
basically guys this is my project, and i dont have the funds atm to do a full single turbo conversion, and i want to get my car on the road so i can drive it. reason i ask this question is just to see wheather or not i can safely run this set up. i know the factory twins are to small with comparison to the engine and its mods, but im not after big power i just want it to run so i can drive it and break the engine in.
Trending Topics
#8
Moderator
iTrader: (3)
well, if it's pretty much just for break-in, then i don't see why it should be an issue. if you listen to Blue TII, it might even be more to your benefit because if the lag is as bad as he describes, then it pretty much guarantees you don't boost the engine while breaking it in.
#13
Urban Combat Vet
iTrader: (16)
^At 14 psi, the stock twins are 40 % over what MAZDA intended them. They'll be making as much heat as boost, and won't last long doing it. That's not to say you shouldn't appreciate the qualities of the stock sequential twins. You just don't need 14 psi to do it IMO.
#14
Junior Member
Join Date: Sep 2014
Location: Trinidad And Tobago
Posts: 8
Likes: 0
Received 0 Likes
on
0 Posts
no offence bro, but why do reputable Japanese rotary tuners i.e. Knightsports, re-amemiya, mines, r-magic etc produce re-mapped ecu tuned for 0.9, 1.0 and 1.1 bar of boost???
I mean taken into consideration a proper intercooler setup that would significantly reduce intake temps. I run a knightsports 4beat ecu tuned for 1.0 bar boost with a stock intercooler setup, daily driven where ambient temps are 31 degree Celsius and above with no problems been like this for some years, no turbo failure
I mean taken into consideration a proper intercooler setup that would significantly reduce intake temps. I run a knightsports 4beat ecu tuned for 1.0 bar boost with a stock intercooler setup, daily driven where ambient temps are 31 degree Celsius and above with no problems been like this for some years, no turbo failure
#15
Urban Combat Vet
iTrader: (16)
No offense taken...'bro'. But just because they're well-known, Japanese, and "tuners", doesn't automatically make them reputable. They're likely just playing to the market, full of people like yourself.
You're running the stock IC but speak of running a "proper intercooler set-up"? IMO your stock IC is not "proper" for 14.5 psi (1 bar) and strongly suspect your IATs are silly high. Probably fortunately for you....with the pressure drop on the stock IC, the manifold is seeing a lot less than 14.5. Still, your stock twins are working way harder...and their life-span has been shortened.
BTW, love your island.
You're running the stock IC but speak of running a "proper intercooler set-up"? IMO your stock IC is not "proper" for 14.5 psi (1 bar) and strongly suspect your IATs are silly high. Probably fortunately for you....with the pressure drop on the stock IC, the manifold is seeing a lot less than 14.5. Still, your stock twins are working way harder...and their life-span has been shortened.
BTW, love your island.
#16
Junior Member
Join Date: Sep 2014
Location: Trinidad And Tobago
Posts: 8
Likes: 0
Received 0 Likes
on
0 Posts
hey hey don't jump on my stock inter-heater , that's all money can afford at the moment, I usually run stock boost during the day, only with proper fuel and cooler temps I may run 1.0 bar. I agree 100% on turbos passing its efficiency levels at or above 14 psi, just testing your knowledge
I have acquired a pair of knightsports rf420 that I will install soon cost me like $53USD , but is in desperate need of a rebuild. Trinidad is a great country
I have acquired a pair of knightsports rf420 that I will install soon cost me like $53USD , but is in desperate need of a rebuild. Trinidad is a great country
#17
Engine, Not Motor
iTrader: (1)
Join Date: Feb 2001
Location: London, Ontario, Canada
Posts: 29,789
Likes: 0
Received 108 Likes
on
91 Posts
Skip the Bridgeport. Unless you are going for higher power levels with a single turbo (500HP +) then your best bet is a street port. You'll also enjoy not getting 8MPG.
#19
Engine, Not Motor
iTrader: (1)
Join Date: Feb 2001
Location: London, Ontario, Canada
Posts: 29,789
Likes: 0
Received 108 Likes
on
91 Posts
No, but I have run half bridgeports on other smallish turbos. It's great in the beginning because the turbo is on/off. Instant boost at any RPM. But the peak power sucks and doesn't do the Bridgeport any justice. So you're wasting all that fuel and dealing with a hard to tune engine for no benefit compared to just properly sizing the turbo.
#20
Full Member
Aaron what about a HBP with a Borg Warner EFR 8374?? I was originally planning on the 7670 because of the fast response but after reading your post I am having second thoughts.. Love you youtube channel btw, cheers
#21
Rotary Motoring
iTrader: (9)
stevexk
Aaron what about a HBP with a Borg Warner EFR 8374??
I'm not Aaron, but-
Yes, this is a really really good combination.
There are several bridge and semi p-port circuit race cars in Japan that use the HKS T04Z (which is has 84mm compressor and 74mm turbine wheel major diameters).
This combo would have insane spool and do 450rwhp on low boost and up to 500rwhp on medium boost. Probably couldn't run high boost because the compressor would already be out of flow.
I would recommend lots of external wastegate (like the 60mm on the HKS T04Z) on this combo though as opposed to the popular internal wastegate and maybe even the 1.15AR exhaust housing over the usual 1.05AR one.
#22
Full Member
This combo would have insane spool and do 450rwhp on low boost and up to 500rwhp on medium boost. Probably couldn't run high boost because the compressor would already be out of flow.
I would recommend lots of external wastegate (like the 60mm on the HKS T04Z) on this combo though as opposed to the popular internal wastegate and maybe even the 1.15AR exhaust housing over the usual 1.05AR one.
I would recommend lots of external wastegate (like the 60mm on the HKS T04Z) on this combo though as opposed to the popular internal wastegate and maybe even the 1.15AR exhaust housing over the usual 1.05AR one.
Hmm 450rwhp would be perfect. From what I have been gathering, the fact that a HBP would produce more exhaust would allow it to spool a larger turbo as fast as say a stock port would on a smaller turbo, but still be able to be useful in the higher rpm range. For example sake, how would you compare the response time of a stock port with an efr 7670 vs a HBP on a 8374? What rpm range would you assume the turbos would kick in at? Everyone is trying to tell me to go street port for response time and reliability etc etc.. I understand this would be more beneficial for what I am trying to achieve, but I am stubborn to wanting a half bridge, especially after reading about BDC's HBP's.
So you would suggest EWG for this settup, is it because running lower boost on efr's with an IWG would be susceptible to boost creep? I have come across a thread of someone running into boost creep problems with an IWG efr at 12 psi.. What would you suggest for injector sizing? I am planning to combo all this with a v mount and water injection as well on pump 93. I should also mention I have an apex pfc.
Last edited by stevexk; 02-27-16 at 02:17 PM.
#23
Rotary Motoring
iTrader: (9)
For example sake, how would you compare the response time of a stock port with an efr 7670 vs a HBP on a 8374? What rpm range would you assume the turbos would kick in at
I have no idea, but from watching videos even on a street or stock port the response of the EFR 8374 is really close to the EFR 7670 on the same port.
Sometimes when you drive a car you perceive a more of a difference though, the human body is a sensitive instrument.
I am not 100% sure what you mean by at what RPM the turbos would kick in, but on both turbos right around 3,000rpm is when the boost curve will go nearly vertical.
I have no idea, but from watching videos even on a street or stock port the response of the EFR 8374 is really close to the EFR 7670 on the same port.
Sometimes when you drive a car you perceive a more of a difference though, the human body is a sensitive instrument.
I am not 100% sure what you mean by at what RPM the turbos would kick in, but on both turbos right around 3,000rpm is when the boost curve will go nearly vertical.
Thread
Thread Starter
Forum
Replies
Last Post
CaptainKRM
2nd Generation Specific (1986-1992)
14
08-26-15 09:52 PM