BNR Twin Turbos

[John RX7]

Hey
 
Ive decided i want to be different and stick with my twin turbo set up,i would like to upgrade my twins,ive had a search on here and on google for some BNR turbos,theres not alot of info on the go anywhere,im going on a guees but if i brought brand new bnr its just an upgrade of the standard turbos,iam aiming for about 400 bhp and will be quite happy at that,can anybody sen me in teh right firection or possibly point me in the direction
 
cheers john

[turbo boy]

Try www.rx7store.net

[CharlieP]

Someone was selling some, think it was on here....or maybe FDuk

[PGiljevic]

Hey
 
Ive decided i want to be different and stick with my twin turbo set up,i would like to upgrade my twins,ive had a search on here and on google for some BNR turbos,theres not alot of info on the go anywhere,im going on a guees but if i brought brand new bnr its just an upgrade of the standard turbos,iam aiming for about 400 bhp and will be quite happy at that,can anybody sen me in teh right firection or possibly point me in the direction
 
cheers john

I suggest you do not stick with twins, I have tested every type www.riceracing.com.au (look under VBOX testing page).
 
The BNR\'s are the worst of the upgrade twin turbo\'s, the turbine wheels are too large and they are laggy and have the narrowest power band of them all.
 
The best are the knight Sports RF420, but they are very fragile!
 
Aftermarket T28 BB upgrades are as bad as the BNR\'s for response and power band, but at least they are reliable.
 
I suggest you go single turbo, look at my site for graphic real world testings as to why power and reliability all in one, with widest power band and least expense long term :cheers

[787b]

he is right go with single turbo set up for that kind of power , im using a turbonetics on mine.:cheers

[stylus350]

Think about how you use the car. If like me you use it everyday for everything then NOTHING will give you the low down pull and response of the stock twins in sequential. I wait (hope) to be proven wrong.

I\'ve been single (in the 500+ club a long time ago) and as always used that car as I have all three of my FD\'s as regular transport. Currently I run twins with the usual mods and a PFC and it is without question the most fun setup I have ever tried in an FD that still retains its Rotary. Back roads are where these cars should be driven and for that it is very entertaining indeed! Straight lines suck - no matter how much power you have gunning it on the straights gets very boring very quickly.

A couple of points to remember:

If you search through threads you will see that many people who go single never had the twins working as well as they could be.

Lots don\'t use the car regularly.

There aren\'t many twisting winding back roads in most of the US.


A small single like a TO4e will get you 400 at most if set up very well but still won\'t have the low down power of the twins for effortless (but brisk) town driving.

If you car is a toy for occasional use then all of the above is still relevant but much much less important. In fact if I could put mine down long enough for it to become an occasional car I would go single myself. The fact that I can\'t put it down is the reason I won\'t.

[PGiljevic]

In my own case I have had perfectly working twins and done them for customers as well, sequentially (~120mph cars in 1/4 mile test).

Any decent single turbo (up to T04Z) with correct set up will provided full boost pressure at ~3600rpm! this V\'s ~3000rpm for the tiny single stage for the twins :WaveBye The biggest difference is there is no steps in the power curve and you also end up with 80bhp+ extra power with all the same variables :yes

The twins are a novelty, nothing more, for when you go to a well set up single turbo 13B-REW you will never ever go back to the oil leaking, stepped power band, limited rpm, hopeless set up they come with from the factory :flamed

ALL of the modified twins on the market are nothing short of hopeless, I am happy to be proved wrong by anyone/someone? Having bought,fitted,tested them all I as a free service publish all the information regarding these used on a stock 13B-REW motor base, anyone can go and look at the average power band figures (90-140 tests) or overall power and speed tests (circuit times, qtr mile times and speeds) what you wont get to see is how crap they are for durability sadly or how a total PIA they are to work on.

IF you want a reall responsive set up buy a Garrett T04Z (1.00A/R divided rear housing), use a HKS fabricated exhaust manifold, SMB 3.5" exhaust, get it tuned properly and you will have the most fun car to drive in the mountians you will ever experience, super responsive, very powrful, and durablity to boot. :Typing 0-60mph in under 4 seconds on any road (driven by virtually anyone) and 200mph top speed if you are brave enough. :Typing

[ashc]

good points rice - i have the rf420s with large streetport all the fueling mods and intercooler etc but they\'re currently being rebuilt due to an internal oil seal failure on their first proper dyno run (bah!) so i can\'t give you a power figure and point taken re. fragile!!

[PGiljevic]

good points rice - i have the rf420s with large streetport all the fueling mods and intercooler etc but they\'re currently being rebuilt due to an internal oil seal failure on their first proper dyno run (bah!) so i can\'t give you a power figure and point taken re. fragile!!

I went through 3 sets (customers cars) of RF420\'s all with the same problem!

Power graphs on my site of one in no seq form > (271rwkw on dynodynamics guess machine) = (you blokes would guess the power at ~457bhp on the opimistic figures/multipliers I see your shops using as conversion factors!). You will see on my own proper rwkw ratings that match physics its honest ~250rwkw region @ 19psi inlet boost pressure. This is V\'s 285rwkw @ 17.2psi for a T04Z as a comparison. http://www.riceracing.com.au/rides/SeriesVIII_SpiritR.htm I did squeeze a lap record out of this set up which has still not been equalled or beaten for a twins car) but the turbo\'s failed in one day at the track!

You can compare them to two different cars on T04Z, with other incremental times to match along with the actual recorded power output as tested by me > http://www.riceracing.com.au/vbox-iii-testing-tuning.htm (RF420 third or so from top of list of road car set ups) they need a .... load of boost to get anywhere near a good single turbo, and you will see MANY other modified twins and stock twins way down the order in on road performance and power meansures too.

Go single :burnout

[CharlieP]

\'\'The biggest difference is there is no steps in the power curve and you also end up with 80bhp+ extra power with all the same variables\'\'

Sounds like you should get yourself a decent mapper then :rollin

Stylus hit the nail on the head, you can\'t beat the twins for everyday driving, singles are all about power....I\'ve had both, been in both, and much prefer twins...so you don\'t get 4-500 bhp...maybe you\'ll keep your licence a bit longer!

[stylus350]

In my own case I have had perfectly working twins and done them for customers as well, sequentially (~120mph cars in 1/4 mile test).

Any decent single turbo (up to T04Z) with correct set up will provided full boost pressure at ~3600rpm! this V\'s ~3000rpm for the tiny single stage for the twins :WaveBye The biggest difference is there is no steps in the power curve and you also end up with 80bhp+ extra power with all the same variables :yes

The twins are a novelty, nothing more, for when you go to a well set up single turbo 13B-REW you will never ever go back to the oil leaking, stepped power band, limited rpm, hopeless set up they come with from the factory :flamed

ALL of the modified twins on the market are nothing short of hopeless, I am happy to be proved wrong by anyone/someone? Having bought,fitted,tested them all I as a free service publish all the information regarding these used on a stock 13B-REW motor base, anyone can go and look at the average power band figures (90-140 tests) or overall power and speed tests (circuit times, qtr mile times and speeds) what you wont get to see is how crap they are for durability sadly or how a total PIA they are to work on.

IF you want a reall responsive set up buy a Garrett T04Z (1.00A/R divided rear housing), use a HKS fabricated exhaust manifold, SMB 3.5" exhaust, get it tuned properly and you will have the most fun car to drive in the mountians you will ever experience, super responsive, very powrful, and durablity to boot. :Typing 0-60mph in under 4 seconds on any road (driven by virtually anyone) and 200mph top speed if you are brave enough. :Typing

Not sure what you mean on the twins I get positive boost at 1700rpm and .7 to .8 bar by just over 2k.

[John RX7]

alot of good information here,i think topic getting covered,I\'m just going to throw in an idea of efini twin turbos,ive had a look at these a bit more expenisve then BNRs are they more responsive and more reliable,or do they flop  and my driving needs are a weekend play think i have a van during the week,mainly street use so less lag the better,i do have country roads,and iam hoping to do a couple of circuits this year,   but iam edging towards single turbo,but will aim for 450bhp as my girlfriend occasionally drives lol

[PGiljevic]

\'\'The biggest difference is there is no steps in the power curve and you also end up with 80bhp+ extra power with all the same variables\'\'

Sounds like you should get yourself a decent mapper then :rollin

Stylus hit the nail on the head, you can\'t beat the twins for everyday driving, singles are all about power....I\'ve had both, been in both, and much prefer twins...so you don\'t get 4-500 bhp...maybe you\'ll keep your licence a bit longer!

:2eek I have done more RX7\'s than most others combined and take offense to your childish remarks :2eek

Go set a set of twins to ~20psi and come back to me with a proper data log of where it reaches this boost in 3rd gear on a road not on an artificial dyno thanks. AND show us the POWER not just the token boost level.

ALL sequential twins have a stepped power band and boost plot.

ALL twins fail at high power (stock based) only ones that do not are Garrett GT28bb inserts, these though have a poor power band as I already stated and proved.

I don\'t know of anyone who drives their RX7 (and can drive!) who uses sub 3000rpm except when maybe reverse parking! so the merit of oil leaking underpowered sequentials is really pointless unless your trying to compensate for failing on every other important point :Giggle

[PGiljevic]

alot of good information here,i think topic getting covered,I\'m just going to throw in an idea of efini twin turbos,ive had a look at these a bit more expenisve then BNRs are they more responsive and more reliable,or do they flop  and my driving needs are a weekend play think i have a van during the week,mainly street use so less lag the better,i do have country roads,and iam hoping to do a couple of circuits this year,   but iam edging towards single turbo,but will aim for 450bhp as my girlfriend occasionally drives lol

They are worse.

Fundamental to all the twins is poor design in utilizing the rotary exhaust energy, you really need an open clean designed header and a dual entry turbine of appropriate design to utilize this excess energy in the rotary exhaust.

All of the twins have excessive pumping losses and turbine losses imposed on the poor little engine, this is why they make so much less power (all factors being equal) compared to a single turbo.

You forgo the pointless token sub 3000rpm boost spike for far superior power & transient response from 3500rpm to 8000rpm........ and most importantly its many times more reliable and more fun to drive (opposite to what some people are trying to convince others of here).

I have tuned/modified/ and tested hundreds of RX7\'s ........ the advice comes for free :Thumbs-up

[PGiljevic]

Not sure what you mean on the twins I get positive boost at 1700rpm and .7 to .8 bar by just over 2k.

True, if you want to race from 2500rpm to 3500rpm you probably will win, ANYTHING from 3500rpm you will loose :cheers

I can show you track data from my own car where I just leave it in 3rd gear out of slow corners (3000rpm) and it pulls like a freight train on my T04Z to the point if there is any lateral loading the Race Logic Traction Control is active! I drive a twins set up (my own car, you can see video of it on my site!) and I can tell you from personal experience it is slower out of low speed corners apex to corner exit, and then it get destroyed once you actually can use the power.

On the actual road this problem with the sequential twins is even far more extreme and their "benefit" if even more of a negative to the point where it is totally useless. (much less traction on road tires, and dirtier road surfaces to deal with).

The only thing the twins are good at is pulling away from the lights at 1000rpm and tailing it, the acceleration to 3000rpm is enjoyable, everything else they are garbage at and not worth the troubles.

0-100kmh test they are over a second slower than a single turbo car.