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I have been tuning the S300SX FMW and KPro III on my S2000 for a while now. I like to get things close on the street before going to a dyno. I thought that some of you might be interested in boost threshold results from my S300SX FMW with 0.91 a/r flat tipped turbine wheel. This is with a 3" exhaust and high flow cat.

[attachment=65052:Boost vs RPM vs Gear.png]

4th gear - pressure readings from the intake manifold (3rd gear is similar):
2500 rpm - 104 kPa - 0.73 psig
3000 rpm - 113 kPa - 2 psig (same pressure @ 2500 rpm in 6th gear)
3500 rpm - 127 kPa - 4 psig (same pressure @ 3000 rpm in 6th gear)
4000 rpm - 150 kPa - 7.4 psig
4500 rpm - 180 kPa - 11.75 psig
5000 rpm - full boost

Note that this is all preliminary because this is running on the spring only, ignition timing is low, and I haven't tuned the boost controller. There is some boost drop between gears, but I am also not revving to 8k yet.

For what it's worth, my SPEC stage 2 pressure plate with OEM disk slips miserably after 4800 rpm. It will be replaced with a SOS Carbon clutch soon. This could be a big mistake (I love the low noise and feel of my current setup), but I want to make sure I have a clutch that can handle everything I throw at it.

Tim

lude92_si

How do u like the s300 so far? I'm about to get my s200sx fmw tuned.I know from just putting around breaking my diff in this thing is going to spool fast. I'm excited to see what it can do.

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It's a great turbo. It makes up to 4 psi at 3000 rpm, so it feels pretty responsive even at low rpm and is very easy to drive. With that said, it's not a small turbo. It doesn't seem to spool as quickly as my old non-divided GT3076R, but it's been a while since I drove the previous turbo setup, so it's hard to be sure.


A few weeks ago, I bought an ATP 0.82 non-divided T4 turbine housing for my GT3076R. I hope to do some comparison logs between it and the S300SX FMW. I may throw in a T04Z just for fun. It seems like all of the turbo comparisons I see are done on different cars with vastly different setups.

After posting this, I continued to pull boost vs gear data out of my data logs. I'm still tuning boost control so some of the data is incomplete, but I hope to be able to post boost vs rpm graphs by gear within the next week or two. What I have found so far is very interesting.

For example -
4000 rpm in 2nd gear = 2.5 psi of boost
4000 rpm in 5th gear = 9 psi of boost

Tim

lude92_si

Interesting..I'm running a .70ar on my 200sx fmw and hoping for fast spool and 600whp. haven't seen anyone run this turbo yet so I'm not sure what its going to do. I looked at the 300sx fmw but thought it may be to big. Since I'm looking for a fast street car and don't do highway pulls much.

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On the drive to work this morning, I noticed that the wastegate opens around 4000 rpm. If I remember correctly, I have a 10 psi spring in the wastegate. I will have to look at the data logs, but if that is correct, then the spool is not that much different from the GT3076R I had before.

Tim

suprmonky73

where in kennett are you able to use this thing!!!
route 1 heading west?

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There are a lot of good places to open it up around here, but it's usually for very short durations. The terrain around here is why I have occasionally wondered whether the S300SX FMW was too big. I find that I spend most of my time between 3000 and 7000 rpm.


I added a boost vs rpm vs gear graph to the first post. The boost flatlines on the graph because I was testing different boost duty cycles and had to combine multiple datalogs to get the graph. Full boost should occur from 4000-6000 rpm depending on gear and the exact boost level you run.

Tim