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      12-21-2018, 10:31 AM   #32
nothingman
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Good read from a guy on another forum who has a 2012 N55 135i and went with the Speedtech EFR7670 and does a comparison to both PS2 and Big Boost:

https://www.n54tech.com/forums/showthread.php?t=50451

Quote:
I have installed both a PS2 and a speedtech kit, seem in depth install of the bigboost kit and tuned the s*** out of a ps2 kit. We are coming up to the holiday season and with 3 different great turbo options out here I wanted to provide some feedback for those who do not know the important but untold differences

I have installed both a PS2 and a speedtech kit, seem in depth install of the bigboost kit and tuned the s*** out of a ps2 kit. We are coming up to the holiday season and with 3 different great turbo options out here I wanted to provide some feedback for those who do not know the important but untowld differences. Ill start with the tried and true.

Pure stage 2: Ok, this has a cult following, for good reason.
2500+750+135+250~3635 (comparing to no core to keep apples to apples)
Pro:
- Plug and play bolt on
- Pretty reliable 500whp
- Dual seals on both sides. VERY reliable from a hydrid
- OEM look, near OEM spool
- Fits every platform
- Fits engine bay well (no need to move things)
Cons:
- Capped at say 550 whp. You can say more but im going to use average. This will require e85 or meth for octane and you will need 24-26 psi
- Restrictive stock turbofold. This puts stress on engine and on turbine wheel. Note: Pure has revised turbine wheel to much beefier one due to them shattering at high boost, only so much leverage you can get from a blade. The cult following has the few of these failures covered in haze and smoke

Overall you CANNOT go wrong with PS2. If you are happy, honestly happy, long term with 500whp then this is your option. Its reliable, can take a beating, good company, and you have a entire cult to join with you . There is a reason for it..... N55 is likely capped to 600-650 whp, and you could maybe get there with a PS2, but the engine will not be happy. I think you should limit safe use of PS2 to 500.

Bigboost: Wasn't sure about this kit until I saw it installed.
4000-5250 depending on turbo and BOV options
Pro:
- cast manifold (this may be a con for some).
- Turbo fits engine bay OK. Sits higher than speedtech, smaller frame turbo
- - FAR less pre turbo back pressure. Should correlate to better VE and happier engine (big pro in my book)
- DO not have to move water pump (I believe, didn't appear to need to)
- Provide hard lines for inlet, outlet, and coolant *****
- Coolant pipe design allows for "adjustments" to fit engine bay
- Should be able to hit 600whp with right turbo
- get to use a external BOV
Cons:
- Non preferred turbo. This is only one line but its a very important one
- manifold uses a gasket instead of the OEM nose + graphite ring
- pricey for the turbo
- slower spool compared to PS2 and speedtech
- Manifold is a heavy pita, so is engine mount, no concern for weight on this kit. Although I think reliability and fitment are likely more important
- coolant line has smaller ID, looks to be a good bit, this may or may not matter. As a engineer it concerns me, but if nobodies getting high temp warnings, may not matter.

Overall the bigboost kit looks good. comes from a actual company, the kit definitely fits a 135i. I have had a hard time getting ahold of them, there number does not work and its been days with no response via email. Fitment is good, hardware is good minus turbo, looks like a pretty solid options, wish it came with a better turbo, would make it a great kit. Turbo is the heart of the thing.

Speedtech: This was my choice for many reasons, but would like to update post install. I chose the speedtech kit because I thought the manifold was well sorted out but mainly because the EFR turbo. This things has a heart of gold, its a sexy amazing turbo in every way.
3800 no bov needed as its internal.
Note: the speedtech kit does not currently fit the e82 chassis. I believe I was the one to learn this. It also does not have a port for the DCT cooler. Speedtech has great customer service though and Jeff has been helpful and easy to get ahold of since day 1. I have shared all my lessons with him and would expect a e82 kit in 3-6 months. If you need to make one fit before then then email me and i can show you what I fabricated to make it work.
Pro:
- Best manifold: well through through manifold thats cast but lightish designed using CFD
- BY FAR BEST turbo: EFR has gamma Ti wheels, best casting methods, internal wastegate, GIANT bearings and dual seals. Its a beast. FOr this reason the center section and parts of comp/turbine are much larger than say a gtx or the bigboost turbo.
- PS2 spool (or better, time will tell)
- FAR less pre turbo back pressure. Should correlate to better VE and happier engine (big pro in my book)
- ******** and up pipe are well made
Cons:
- Tight: this thing barely fits, it fits, but barely.
- 4 ply silicone is used for all coolant piping and outlet pipe to IC. I think it works, but i prefer hard lines. its flexible so makes the install a bit easier, maybe
- Have to move water pump forward using provided mount
- does not fit e82 (currently)

All in all I have learned several things.
1. Use PS2 if you goals are 500whp or 450 on pump
2. drop the subframe. I did mine without, the bigboost was done dropping, way way easier
3. if you go bigboost or speedtech invest in some dei thermal tape and headerwrap and wrap everything, tight, then silicone spray. Dont install twice because of heat
4. On speedtech only
- move diverter valve solenoid, unbolt from turbo prior to putting it on. use longer hose and move it near coolant tank
- If speedtech in next 6 months you will need some aluminum tubing and fittings to make a hardline to go from water pump bend to up near block coolant inlet. This uses aluminum in the hottest parts vs 4ply. I think wrapped 4 ply would be ok also though, if this is what speedtech ends up doing.
- If going on e chassis make sure you have the right wastegate actuator rod length. The e82 has a longer one by about a inch compared to the f30, so you will have to cut it.

Ok I think thats about it. I still think, especially for the price, the speedtech kit is the only stage 3 I would go with. If bigboost updated its turbo then that might change depending on cost and how they did it. At the end of the day you are paying for the
- turbo
- manifold
- connection system

If you are a f chassis, or even a e90 (probably) then the speedtech is the choice. I would go speedtech even if my goals where 500, but thats just me. If you are e82 you will need bigboost or be ready to fabricate, unless speedtech comes up with a solution, which I am sure they will since its a relatively easy fix. If you are DCT you will be in same boat as e82.

Just some food for thought guys, I hope it helps make your decisions more justified.
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