Yeah that is a likelihood hence the poor power figures .

 

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 .

 

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

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 .

 

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

I rather like that torque / power curve

 

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 .

 

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