shadow24v

Hello,

I wanted to ask for some input regarding selecting a turbo for a 6-port turbo project I am planning out. I have done a lot of reading and still am not quite sure which turbo to look at for this application. I have seen reference to a few turbos that may meet my criteria and was hoping to get some kind of feedback regarding their performance vs. the goals/parameters I currently have. The turbos that I see that "MAY" work for this setup are listed below. Please note, I am hoping to find a turbo that doesn't break the bank (a la BW EFR turbos for ~$1500, while nice, they are out of the current budget).

On a side note, Would a stock S4 turbo be able to flow enough for 350hp if not using a stock TII manifold/TMIC setup?

Basic goals
1) 350hp
2) quick response / good low end, not shooting for super high HP
3) Good daily drivability manners

Parameters
1) stock S4 6-port motor
2) Exhaust manifold TBD (one-off seems most likely)
3) Retain 6-port actuation on stock S4 N/A manifold (triggered by Megasquirt)
4) Large FMIC for intake charge temp mitigation (3"x28"x16" if I remember correctly)
5) EV14 injectors & pump upgrade (4x750 or 2x550 and 2x1000 or other variations, May adjust to enable E85 use)
6) Megasquirt-II EMS

Potential turbos
1) 60-1 hybrid (either BNR stage 3/4 or DIY as I have a stock S4 turbo already)
2) GT3082R
3) Holset HX35 or similar variant (haven't seen many holsets used on the forums so far)
4) BW S200SX

lastphaseofthis

iTrader: (8)

to compare to my current build up..
ms3pro, uncapped yellow rx8(880cc)x2 and ev14 2200cc x2, walbro 450.
retain 6 port activators... vmount ic 3 in 3 out.
water injection on pump, then switching to e85.
borg warner s200sxe 7670... top mounted and routed around the s4 na lower intake.

goal is to achieve or beat blue TIIs efr 7670's 400ftlbs of torque by 4k rpm. i doubt it will happen, as his is a freaking EFR. this turbo is known to limit at around 420.. the SXE (EWG) version may push higher then that so we will be able to see that as well.

if you for sure never wanted more then 350, you could possible get sooner torque then me and give us all view into what the 7070 SXE would do, its a 52 mm compressor instead of the 57 on the 7670 i have.. so it will spool a wee bit sooner, and make a little less on the top... both of these turbos are so new, no one has ran them in yet...

shadow24v

Thanks for the insight into your build so far. It does sound like it will be a responsive setup once complete. For me, 350 is a flexible target chosen mainly for drivability and reliability reasons due to running a stock S4 with some miles on it (for now). If we get 400hp, that is fine however the big power will be in the other RX7 (longer timeframe, built motor, Megasquirt-III etc.).

I am leaning toward a 60-1 hybrid at the moment (cost and packaging) provided I can find the parts to upgrade the stock S4 turbo I have. I am still open to more info regarding other reasonable cost options though. A quick gander on the web shows the S200SX seems to ball-park around $600 in a few variations. That isn't too bad price-wise and lower than I initially suspected.

Regarding your S200SX, what exhaust housing did you select for your application?

lastphaseofthis

iTrader: (8)

so far i have part number 177191 .83 a/r divided. its the smallest a/r

i did get a quote from g/popshop to attempt to mill a stock s5 turbine housing to accept the 7670 SXE.. i would suggest that route to you, with the 7070 SXE turbo it will be more likely to clear the s4 lower intake. but there will still be some clearance to be made.

i will later on run the 7670 on the s5 turbine housing but i dont think it will hold low boost, it going to be like 15 and up..

shadow24v

Ok, so we have the BW SX200 as a possibility and the semi-known quantity for the BNR stage 3/4 (60-1) setup. Are there factors that would make the other two turbos I listed not a good fit or any other turbos that may match up?

I haven't found much info on anyone running a turbo on a functional 6-port manifold yet. Im intrigued to see how the functional 6-ports affect the torque curve compared to the larger 4-port turbo setup. I wonder if the 6-ports would make a slightly larger turbo act more responsive (maintaining intake velocity) than a 4-port with the same turbo...

Shainiac

iTrader: (7)

IF you could get the 6 ports to actually work, maaaybe. But if you pull the sleeves and port match a TII intake like everyone else, it WILL be less responsive than 4port plates. I built a high comp 6-port turbo and absolutely hated it. It was so gutless at low RPM out of boost. switched to a 4 port and it was worlds better, everywhere. I understand that the plates are much cheaper than TII stuff, but there is a reason.

lastphaseofthis

iTrader: (8)

happen to know the results in leaving the sleeves in place, locked in closed position..and making it a 4 port? i understand they are way under sized compared to the normal 4 ports. but it would tell us for sure that the reason the 6 ports suck is because of the late closing time of the aux ports, though it probably a combination of that and high intake surface area causing drag.

Shainiac

iTrader: (7)

I don't think it has much to do with the port timing at all. I think it's mostly the large volume and poor port shape, specifically the end of the 5/6th ports where it makes a sharp 90 bend with a lip. with the port closed, you would be flowing against a capped tube essentially. part of the problem is that port matching the TII manifolds is a compromise. The stock 6-port manifold meets the block at a much shallower angle. TII is fairly abrupt, even with the short TII ports. Using 6port irons is definitely more cost effective, especially given that S5 TII rear irons are few and far between, but it's still a compromise.

lastphaseofthis

iTrader: (8)

so has no one attempted to put the 6 port n/a lower on the 6 port block and then turbo it? sure i thought this had been done before.. along time ago i had a 6 port with the 4 port lower on the stock turbo, and i dont recall having any worse spool... power might have been less i can't say it was ever dyno'd but it made the same 10 psi by 3200 rpm.. 5 at around 2800.

Monkman33

iTrader: (28)

The best mod you can do to an FD RX7 is to buy a second car as a daily driver.

Turblown

iTrader: (12)

You can simulate this on dyno with an Rx8. Wire the aux ports open vs closed. It moves the torque curve left or right 600+RPMS. Ports wire open( 6 port engine) the car loses 15% torque for most of the entire powerband( I cannot remember off the top of my head but it was up to 6000 atleast).

FwkUiWN

iTrader: (1)

QFT.
Happens in the 8 world a lot.

Aaron Cake

iTrader: (1)

It is not running yet but this is how I set up my Cosmo.

GSL-SE lower intake, custom middle intake, FD upper intake. GT3076R. Built a manifold to fit around the aux port actuators (tight space). Using the Atkins aux port valve sleeves. Actuators will be plumbed into small air reservoir tank fed via check valve from the intake manifold and actuated with a solenoid triggered by the MS3-Pro.

lastphaseofthis

iTrader: (8)

GSL-SE lower, you're a weird one.. i recall them being small.., but other then that and turbo (SXE 7670 here), my same receipt.. s4 LOWER with aux portsw/inserts, a tank with check valve, ms3 pro... E85! or well im gonna have flex, and shoot for e50 most of the time... i kinda want a real time alcohol percent gauge... maybe i'll lookin into the dash options from a tablet?

Aaron Cake

iTrader: (1)

It's an older 13B w/RX-5 Cosmo housings and thus the only 6 port irons to fit were GSL-SE due to the coolant seal grooves. So by necessity, the GSL-SE lower was used. I've also designed my fuel system for E85 capability and will use a flex fuel sensor. I think the sensor outputs a PWM signal according to the amount of alcohol in the fuel. Should be easy to translate to an analog voltage for a gauge with the Arduino of your choice.

lastphaseofthis

iTrader: (8)

you're right that its a fequency based sensor, i have looked at the aem and the GM both are 50 htz for 0 percent, and 150 for 100. with a linear scale... HAS to go to the digital FEQ pin on the ms3pro. I hope to use a smart phone or something next to my gauge clusters. i think i can make it look nice.

i swapped manifolds from s5 onto my 84 13b-egi but i cant remember which lower i used and why the s4 wouldn't work..

shadow24v

So I'm currently leaning towards the turbo lastphaseofthis suggested, the S200SXE 57mm with the .83A/R. it is relatively cost effective compared with trying to rebuild/hybridize a stock S4/S5 turbo but would more adequately handle the airflow for ~350hp without over stressing the turbo. Looking at the turbo map (JEGS listing) it appears that running max boost of about 20psi would provide adequate power, but also keep the turbo fairly efficient, even in lower boost/RPM ranges.