muibubbles

iTrader: (36)

bit behind in the beginning or overall?

ScorpionT

iTrader: (3)

Sorry, it was a reference to spool.

BLitzed33

I would stick with a smaller compressor if you want response over peak. These are pretty fast spooling turbos for being non ball bearing.

Here is a thread from 4 years ago of my car with the Borg Warner 1.15 a/r with a 61.5mm compressor wheel at 25 lbs it made 544 whp with full 25 lbs spool at around 4400 rpms non ball bearing looking at the graph in the thread...

https://www.rx7club.com/single-turbo-rx-7s-23/pfsupercars-built-tuned-makes-544-whp-537008/

at 27 lbs it maxed out at 561 whp. At 20 lbs it made 500whp with full spool around 4250 rpms. At 16.8 lbs it made 427 and full boost was 4K. here is the graphs...

I had a 1.15 A/R, gets the heat out which is key to the survival along with proper fuel and tuning. I ended up going with the S366 and with a normal run of the mill street port and OEM 2mm seals, made 610 whp. Here is that graph...

Good luck.

muibubbles

iTrader: (36)

what is your AR on that one? what psi are those graphs @?

BLitzed33

1.15 a/r
544=25 psi
427=16.8 psi
610=28 psi
561=27 psi

muibubbles

iTrader: (36)

am i correct when i say bigger A/R = higher peak hp at lower boost?but more lag?

how do you think the .91 A/r t4 divided will do on a hbp?

BLitzed33

The higher peak is more correct, however the compressor wheel more determines the higher hp at lower boost. The bigger the A/R the more lag, but more flow for top end power band essentially shifting it to the right. However the rotary engine exhaust pulses utilize a bigger A/R more efficiently and beneficial for getting the back pressure and heat out and it isnt affected as much as say a small 4 cylinder engine

I would use the R85 turbo for your street application...but there are many turbo's out there that will do what you are wanting to do. I just chimed in because you were asking about the BW turbo that I had. I did notice it spooled a bit later than my R85 BW setup, but it netted better top end. Good luck

muibubbles

iTrader: (36)

^^ im getting kinda confussed... you mentioned "idid notice it spooled a bit later than my r85 bw set up" i though the r85 was kgparts turbo.. not bw?

BLitzed33

A R85 turbo is a borq warner turbo, essentially a off the shelf truck turbo which you can get from bullseye power turbochargers and the only thing you have to change is the flange on the turbine housing as the V-band section is too thick from the factory (at least if you use the 1.15 A/R). R85 is the just the name they chose to use to market the turbo and changed the v band flange.
I originally had a R85 (BORG WARNER) which is a 61.5 mm compressor with a 1.15 a/r. I wanted more power, so I upgraded to a bullseye power turbo...which is a S366. The turbos (r85 and s366) are off the shelf turbos. I believe the R85 is called a S361 or S362 or something like that from bullseye. I had to ask them to use the 1.15 A/R turbine housing on my S366, which they had on the shelf because all of these turbo's do not use the 1.15 a/r.

The reason the S366 had slower spool was because the compressor wheel was 5.5 mm bigger than my R85, but everything else was identical (turbine wheel size and A/R and front cover.)

Again, I would recommmend you go with the smaller compressor wheel (61.5-62mm)with the extended tip vs the S366(66mm) for spool response and a larger A/R. 400 whp is plenty enough for the street use and since you are going half bridge, you will be making more power at lower boost vs street port. I was only on a simple street port and made 561@27 lbs maxed out on the R85 (61.5mm). If you are a good driver....350whp will net mid to high 11's in the quarter.

If you looked at all my graphs...the only S366 I have is the one with 610 whp...all others were on the R85

muibubbles

iTrader: (36)

well my reasoning for going "wanting" to go with the s366 was beacuse i didnt want to run insane boost.. your 561@ 27 is nice, but there is noooo way i wanna run more then 20psi, i would like to make 450-500 at 18psi, if it cant be done, then it cant be done...

i dont mind lag i just dont want to be sitting all day and then catch it... thats why im opting for the .91 A/R.. well atleast thats my logic and sense... does my reasoning make sense?

BLitzed33

let me put it this way...my R85 made around 500 whp at 20 lbs of boost on a street port. Your HBP will make that power before with better response with the smaller compressor wheel like the R85 and still make the numbers you want without the extra lag. Honestly, you dont need 500 whp for the street, you are going to have a hard time hooking up on street tires. You said you want to sacrafice peak hp for response in your OP. I think you will like the spool characteristics of the 61-62mm wheel.
Dont get caught up in the numbers game, as there are many more factors that come into play. I have given you my experience and advice, but you are going to do what you want. Good luck on whatever turbo you go with.