Upgrading twin turbos?
 

Hi everyone,

I always hear about people upgrading from the stock twin turbo to a single turbine. I am not a fan of the "peakyness" of the single, but I am still looking for more from my 7. Has anyone tried upgrading the stock twin-turbo system? what work would need to be done to replace the individual turbos?

John

Already done. Search on BNR Stage 3. I think you'll find more than enough threads to answer your questions.

The only SEQUENTIAL turbo upgrade that i know of are the BNR stage 3 turbo's you send them your turbo core Edit: and 2.5k and they give you back some better ones. i think they are capable of about 18 psi max, i heard some new ones are comming that will be able to reach 20 psi. i assume you mean sequential because if you meant non sequential might as well go single right?

Here is one of Rich (GoodfellaFD3s) threads https://www.rx7club.com/time-slips-dyno-121/video-bnr-stage-3-dynapack-results-509445/ , he had the BNR stage 3s for a while before going single. My advice would be go single it seems that sooner or later thats where things end up.

knightsports has a very nice setup for 420 hp check it out

+1

Is there any fabrication involved with these turbos? Or are they a plug and play job? (bar a remap)

I am very interested!

Thanks,

Jon

Plug and play, but you will need to uprate your fueling and intercooler setup aswell...i run Knightsports twins on a stock port engine & BNR's on a extend port and they are both fantastic...where abouts in the UK are you?

From what i've researched, BNR's are the way to go.

There are a few Japanese companies making slight larger twins, i forgotten the others but knightsports is definitely an option.

I love the balance of my bnr stage 3's.

I as checking your site out the other day blitz...did you use any special paint on your tyres or just normal black tyre paint? Its so glossy...

Uprated twins are definatley the way forward for everyday drivabilty and normal use if you dont have open roads where you live...

+8 on the BNR's.

BTW the days of peaky HP curves from single turbos are long gone. :) Ball bearing medium sized turbos FTW!

Thanks for the info Rixio :)

I live in Swansea

Give me a bell matey if you want a chat 07886 208 395 more than happy to help :)

Thanks for all the useful comments, I checked out the BNR's and they seem to be exactly what I'm looking for. Once again, thanks everyone!

John

I need to upgrade my fueling anyways...but to "futureproof" myself when I (eventually) go with the BNR's ... whats the usual route people seem to take?

Only have a standard port at the moment, but will be a large streetport next time the engines out :)

Rixio, if you have messenger, add me :)

socamoto at gmail dot com

I'm running 550cc primaries and 1300cc secondaries on my BNRs.

Managed to score a second hand set of Knightsport RF 420 TURBOS , they have been set up to run parallel but i am converting them back to sequential mode to suit my 2002 Spirit R type A .

To get the most out of them i am increasing my secondary injectors to 1300cc and getting a larger walbro fuel pump as well + fuel regulator .:nod:


Hoping to get around 380 HP - 400 HP at 14 - 16 psi

Some guys here in Australia have bought the BNRS stage 3 however they do not seem to be able to get the power out of them as much as its suggested they should could it be you have better tuners in USA ?

I bet you guys are tuning on a hard dyno. Those mainlines are a killer.

you will need more fuel , I believe you will max those injectors at around 360 whp

And of course you will need a tune.

REVOtune JP sell also a complete better twin turbo assembly (complete)

Was thinking of keeping the primaries at 550 cc for everyday smooth idleing and 1300cc for the secondaries to run these turbos what would you guys suggest would be more adequate , i dont want to max out i like to have a good safety margin ?

Currently running the revo high flow turbos they are a improvement on stock ones but not a huge improvement .

Apparently the Knightsports are faster spooling and create way more power and can handle more boost .

Yeah that is a likelihood hence the poor power figures .:lol:

are these KSs still in production or can you only find em used..?

Any competent tuner should be able to map primary injectors up to 1000cc for smooth idle and normal driveability.

I agree though, you'll likely run out of injector if you're looking for that much HP on 550/1300's... (iirc 1300cc injectors are just 850's that some guy drilled out anyway..)

You may want to consider switching injectors to ev14's in 725/1600, that should net you plenty of fuel potential while still making it easy (enough) for your mapper.

I'll show you non-peaky power out of two different set ups on single turbo units.

GT35R, GT3574R.

look where 200WHP is reached and look at the smoothness and linear power delivery. Show me a sequential dyno that is that smooth and makes that much power down low?

No longer in production i picked my up for $1500 most likely spend another $1500 on total rebuild of them change bushes bearing etc .

However they were over $5000 when new .:nod:

I'm saving some cheddar to get the BNR stage 3's or the gt35. its like $2000 for the new stage 3's and they claim to be able to put down 18lbs of boost with the notorious power balance of the twins which sounds like a good deal. most stock twins start to crack from wear over the past 20 years and need to be rebuilt anyway.

The gt35r is my other option... i could pick one up and they're rather inexpensive. I'm just curious if its close to just plug-n-play after a tune or if i need to buy a bunch of other stuff to set it up the single turbo....

I would say a single turbo is much much easier to install since all the vacuum lines are gone. If you are shooting for mid to high 300WHP+, it doesn't matter if that power comes from a single or BNR stage 3, you will still need to upgrade the clutch, fuel injectors, fuel pump, probably a re-wire of the pump, and any other supporting mods that you see fit (dual oil coolers, radiator, FMIC/VMIC, etc). The GT35R and ones of that size OUTPERFORM the BNR's and the stock twins, even at lower rpms, and at power delivery smoothness. look at most of the dyno's. Most stock sequentials have a power dip during transition, the singles don't. Some singles are able to muster 200WHP BEFORE 4,000 rpm. I haven't seen a single sequential set of twins do this. I have seen many single small to mid size turbo's do this. They do it with less heat as well, since a huge block of iron isn't sitting next to the engine.

Tuning is the same for stock or single turbo. I tuned my single turbo myself, was actually pretty easy.

Get a better pump than the Walbro. I like Bosch 044 but there are others.

You can also run 850 primaries, just mill the primary rail down. 550/1300 might possibly get the power you want but will be right on the edge. With the 850's in primary with proper tune you will have no problem with idle.

https://www.rx7club.com/time-slips-d...2/#post3341489

https://www.rx7club.com/attachments/...yno-sheet2-jpg https://www.rx7club.com/attachments/...yno-sheet2-jpg

i'd say its pretty close to 200 , But these are stock twins , not bnr's or 99 spec twins or knightsports

Now one significant difference is the torque , look at the torque the stock twins put out at 22500 rpm RPM VS the single.. I'm not a V8 guy so i'm not gonna go out and say OHH TORQUEEEEE!!!

But I rather love how my car feels on twins , i've been in single TD04 FD and I just enjoy the twins more.

But you are VERY right about the heat issues , and complexity of the sequential twins with the rats nest and all of that .

If your car is gonna be on the track and stay in the high rpm range say 4k+ all the time .. I'd say go single simpler great powerband , more power period . more reliable

but I don't know I just feel something special for the twins .

Any BNR stage III setup on 13-15lbs should make over 200rwhp at 4000rpms, torque should be 230-250ish as well from 3k rpms on.

https://www.rx7club.com/single-turbo...d-dyno-956766/ if you went with one of these though quite the impressive power / torque curve . I'll look up some similar power BNR twins and see what kinda power / torque curve they have in comparison when I get home .

https://www.rx7club.com/attachments/...dyno-2-355-jpg

Recent BNR twins on the Dyno page https://www.rx7club.com/time-slips-d...g-cm2-1044985/

I rather like that torque / power curve

https://www.rx7club.com/attachments/...-2012-dyno-jpg

We made 433 rwhp @ 18 psi with BNR stage III's. We now run 20 psi so I'm sure we are making right at 460 wheel horsepower.

New Porsche twin turbo saw the rear end recently...

This is a VERY impressive number... I dont think I've seen anyone go this high on the BNR's before . :icon_tup:

some good charts from the stock/BNR tubro group. good dyno's!