I'm set on using a BNR S5 turbo for my 13b-re build due to cost. I just cant decide on which stage to get. The motor has stock ports. I'm looking for a responsive turbo, broad power band, and 300-350 rwhp.

Is that a reasonable objective? Does anybody have suggestions? (other than going gt35r or whatnot) Trying to finish up the project on limited funds. I have all supporting modifications. 750/1680 injectors, haltech e8, FMIC, etc.

 

Consider running some non-seq FD twins? they put out a bit more than the 13B-RE twins, and can likely net you that power. Plus you'll save money, and can save up for a proper single turbo when the time comes.

 

I already have an S5 turbo sitting at home. Another reason I'm going with a single turbo is because I'm doing the install on a S4 FC. I did some research and from what I could gather, the stock RE twins do not fit in the FC. From that, I doubt that the REW twins would fit either. If that is not the case, then I may give non-seq FD twins some thought.

What are FD non-seq twins capable of?

Another thing is the additional heat from twins. FC engine bay air management is pretty poor. Already have a bunch of aluminum sheets at home ready to make some duct work. lol.

 

you can fit the twins in a FC on the RE check out titaniumTT car over on rotarycarclub.com

 

Contact member Flipstar, he has an RE swapped FC with REW twins, I think he's still trying to sell it, but he has a full build thread on it. For the FD twins capability, just search through the 3rd gen section dyno sheets, etc.

And the FC's air management is better than the FD's in my opinion, it's not that bad at all. Again, for money vs. results, you'd be better off with the FD twins vs the FC's BNR upgrade, and save up for a proper single turbo/manifold if they aren't enough eventually.

 

I helped a buddy swap an RE into an FC and the stock twins fit. Only thing we had to do was cut away some of the support under the hood where the piping went because it was to high. This could've just been due to the custom mounts we made though.. The twins are (for me anyways) hard to fit on a 13BT due to the LIM extending a tad bit far from the engine bay than a 13B-RE or 13B-REW LIM so it gives you like 1" of room to try to fit a downpipe in..

 

Thats the same swap I did on my fc, except I set mine up sequential. The rew twins fit very well in there and you actually end up with more room than a third gen. The power is nice too.

 

I just remembered that I still have the 13b-re twins sitting in the corner of my garage. Anybody know how those perform when converted to non-sequential?

I believe the 13b-re had HT-10's and the 13b-rew has HT-12's.

If that is a viable option, then I can put more money aside for a proper single turbo setup.

 

If there is ANY way you can run the stock turbos or FD turbos SEQUENTIAL do it!

I have a TII with a BNR Stage 4 and worked really hard to get a good responsive turbo. Boost right off idle and full 14psi at 3,400rpm, dynoed 340rwhp at 12psi. It is pretty much comparable to a GT35 in terms of power/boost response.

Compared to the sequential twins in my FD it is a dog down low! The same peak power and a lot more under the curve and response is available from the stock twins when in sequential mode.

Parallel twins are super doggy don't do it.

 

only reason I suggested non-seq was because he won't be using the stock computer. Maybe I'm dumb, but I always thought there was no easy way to control them using aftermarket EMS?

 

The sequential twins can be controlled (in less elegant fashion than stock) with a single $10 rpm switch or a switched output from an aftermarket ECU. I haven't personally tested it but I have put the basic diagrams together.

 

Wastegate and prespool get controlled with way more precision than stock with some Hallman Pro RX boost controllers and then you need the rpm switch(s) to open the 2ndary turbo exhaust inlet and pop the intake butterfly open for the switchover.

Precision of boost control and speed/smoothness of switchover will be better than stock/bolt ons, but it won't have have the rpm based 2ndary turbo lock in and throttle position based 2ndary turbo lock out like stock without some more control.

The 2ndary lock in would be the feature I would want to add in with another rpm switch so you are not in a situation at the track passing back and forth through 2ndary turbo transition point in a sweeper while trying to adjust your line with throttle.

2ndary turbo TPS lock out would just help you keep from spilling your drink driving in traffic- meh.

 

Stock Cosmo twins do have a smaller then FD primary turbo with a straight bladed "impact" exhaust wheel for better spool and then a FD sized 2ndary.

They make a little less power than FD twins but still can make the 300-35RWHP you want with awesome response if sequential.

 

you've persuaded me into finding a way to have the haltech control the sequential twins in a smooth, reliable, and predictable manner.

im convinced it'll be able to do it better than the stock ecu since it appears the stock ecu controls changeover based only on rpm. the haltech can probably control it based on rpm and load.

time to do more research!

 

I would sell the twins you have and do a BNR 4. They are good for close to 400hp and it would be much more simple.
Just my .02 though...

 

back in the day we built a stock port cosmo 13b with an s5 turbo and v1 compressor and housing, which i think is about a BNR stage 3

that car was FUN. powerband was very linear, more revs = more power.

it felt more like an NA than turbo even

it got dynoed but the WG wasn't hooked up right, 4psi of boost = 250hp@8500.

 

yea. i thought about it some more and abandoned the twin idea for the sake of simplicity. didnt feel the extra work involved was worth it.

back to my original idea of doing a BNR single for cost and simplicity. just need to decide on what stage to get. leaning more towards a stage 2. quick response is more important to me than making big numbers. maybe a stage 3. decisions... decisions...

 

get a stage 4.

 

response is my priority and it seems the stage 4 probably is not right for me.

 

If response is a priority, get the twins and make them work. I'm sitting @ 405wheel with 328ft'lbs of torque. 250 of those ft/lb's are online by 3500 rpm. Think about that and compare it to a single making 400 wheel.

 

My BNR Stage 4 single only did 340RWHP @12psi (uncorrected though) tuned super conservative (10s AFR dipping to high 9s).

It did have 280Ft/Lb from 3,500rpm (where full boost hit on dynojet) to 6,500rpm where it starts to taper with a hump of torque from 5,000-6,000rpm peaking at 290Ft/Lbs.

If/when I wake it up to ~400RWHP at 17psi boost with decent tune the torque will be much higher as well from 3,500rpm on.

Where my sequential twins in the FD shine is the 2,000-3,000rpm range, right where you are in 90% of daily driving.

TitanimTT, did you set up your controls so you can get max boost on the primary? I think that would help your torque in the lower rpms. I guess it could be hurting from having to flow all the exhaust through the tiny primary turbo though before switchover...

 

Hey BlueTII, nope, I just checked the log and we were at 175kpa or about 10psi @ 3400rpm (where we have the transition starting) then it dips down to about 156kpa - 8lbs by 3900rpm then rising back to 175kpa by 4200 rpm and from there it'll hit 195-200kpa by ~4700 rpm and hold it to my 7500 rpm redline.

So we could max out that primary and squeek out some more torque I'm sure. I specifcally remember having to turn the boost down in those rpm ranges on the street becuase the car was damn twitchy to drive. 15lbs @ 2500 in 5th gear on the highway made for a twitchy car to drive. The turbo's are awesome though, love 'em.