Ok so I am sending my S4 turbo out to Bryan tomorrow to get a stage 2 done and at this time my motor is also being rebuilt with some moderate ports. Basically I would like the advice and observations from people who have or had these turbo's (especially the stage2) as i have noticed people end up with different numbers for different reasons.

I want to make sure that i do what i can to make this set up run hard and effeicent so whether its fuel, timing, tuning, supporting mods etc i just want all the input so i can apply it to my setup and not be dissapointed like people in the past.

And yes... I know there is a thread on BNR turbo's and dyno's but it doesn't get much attention anymore so i am starting this one.

My goal is 320-340whp on 15lbs of boost.

Mods are:
Rebuilt S4 streetported motor
emissions removed
720cc primary injectors
1000cc secondary injectors
Greddy 24 row FMIC w/custom 3 inch piping &HKS SSQ
Microtec LT10
High flow radiator
BNR stage 2 S4turbo
ACT street/strip clutch & 8lb flywheel
RB Turbo back exhaust

 

I know the BNR stage 1 is a T04B V-trim (according to Bryan himself), and I presume it is the same with the stage 2, as the stage 3 and 4 use the 60-1 wheel. The V-trim compressor map should look something like this:



It's certainly capable of the power level you are asking from it (which is right around what the website advertises), but you are pushing its efficiency. Given that rotaries need higher airflow (lb/min) than pistons to make a given power level, you'll likely push that compressor into the less efficient part of the map, probably 70% or under. That means charge temps will start to be elevated. Looking at your mods though, the FMIC should help with that. Just keep an eye on charge temps and closely monitor EGT and timing. Rule of thumb is 1650 F max EGT before the turbo, so maybe 1300-1400 max post turbo. Read up on some of the Howard Coleman EGT threads in the 3rd gen section.

With the potential for high charge temps and the backpressure of a modified stock hotside/turbine wheel, I'd keep leading advance under 15 degrees at full boost and split should be 12 at that point as well. Who is doing your tuning?

 

Well if the EGT's will be too high i can back down to 13-14 lbs.. As long as i hit at least 320whp thats my minimum goal. I would prefer maximum reliability and efficiency over 10-15 extra ponies. Oh and i am open to exploring new mods if they are recommended for whatever reason.. So while i would love to see my set up as is work for me, i would much rather use the right equipment rather than just try and make what i have work for the sake of not spending some extra money.

 

I don't know what's going to happen, quantitatively, so I can't say how much is 'too much' boost. I don't know what your intake or exhaust temps will be, as they are a function of your setup and your tuning.

You can also look into alcohol injection.

 

sweet, that's awesome, I've been looking for an efficiency graph for my BNR stage 2...

now I just need to find out what the units on each axis means

 

Ok, well it will be a good while before the motor is broken in and finally tuned, so i guess then i can see what my EGT's will be.. How hot is too hot?

 

The stage 2 isn't a V trim. Its an H3 T04B. Flows just a bit more than the V. Also a lot of the gains in power are made with the turbine wheel to a certain extent.

Bryan@BNR
205 640 1193

 

Do you have a chart for the stage 2? I was planning on running around 14-15 psi when I get my front mount hooked up, but I'd like to know where that is efficiency wise.

 

i believe the sweet spot is at around 1600. there is a thread that mentions it (by howard coleman) along with why you should look ito water/meth injection. give it a search!

 

http://fc3spro.com/TECH/TURBO/compmap.html

It's the compressor map used as an example. There's an explanation of how to read the graphs too. Basically, at 15psi, the turbo would be in the 72-74% efficiency range (30-40 lbs of air / min).

 

<3

 

Bryan i am sending you my turbo tomorrow who do i make the check out to and who should i use to send it?

 

I would probably either call him or talk to him on aim, those are the best ways to contact him. I made my check out to BNR and send the check via USPS..

 

How about the actual turbo?

 

UPS store.