bmw 135i build

[135boost]

Hi, first posting on this forum so be gentle

so this is my buildup and goals on DD 2008 AT6 135i
i bought the car some 1 year ago for my wife`s DD winter car in a mistake,
former owner told it`s most dangerous winter car he ever had owned
so it was left for me as a toy.

car has assembled when bought catless downpipes and vrfs race fmic.
there was some tuning software inside too with 0,9 bar boost on it.

then it started to go as usual, first jb4, then turbos with 13T-6 billet compressors,
fuel it stage2 pump upgrade and a tbi with hobb switch. and that was setup for last summer but clipped stock turbine-13T compressor and 24 psi boost didn`t satisfy me cause of concern about exhaust manifold back pressure and mismatch turbine compressor sizing so i decide to do something to the issue.

i want very broad torque curve, driveability, minor impact on lag versus stock,
and some degree of power up in a rev range

I surfed around different forums for some month before i decided to contacted Tony from VTT, even there has been horror story`s about customer care, behavior on internet etc. he seems to be a legend in good and bad and asked his opinion about the build and how to proceed it and he suggested to move straight
from my first plans of GC lites to GC`s

after discussion about it i decided to do some mods to the car, weight reduction to 3070 lbs(done), upgraded turbos, db shotguns,(yes, we have very good quality e85
here aviable all around) cold side and hot side silicons, berk street exhaust and other small bits&pieces.

i started then to order parts from VTT and there was a mess, nothing to do with VTT, a bank issue at most and my deposit went to wrong account and on that it took over a week to resolve it but i was in contact with Tony every day about issue and at first, Tonys respond time for questions was extra ordinary fast every single time, and at the end got it done.

so the mod list is now like this
- VTT GC turbos ceramic coated inside out
- VTT ilnets and hot sides
- VRFS race fmic
- charge pile with raceport BOW
- VTT double barrel shotgun
- BERK street exhaust
- fuel it twin fuel pumps
- XHP stage 3 trans software
- quaife LSD
- crank bolt capture
- split second AIC to db shotgun
- JB4
- Trebila tune to 27psi
- ethanol analyzer
- MHD programming tools
- upraded spark plugs
- n20 tmap
- apex racing wheels

there is for sure something missing but get my point of performance
level i`m after.

then to order and install , issues and pros/cons
everything i ordered came in time,except those wheels i waited for 4,5 month, issue with supplier, exhaust came in time, burger tuning parts came in time VTT parts came in time and only missing parts up to date 1 small hose clamp from VTT order.

- Exhaust fitment was perfect, sound could be more softer to my use, my verdict 9/10

- lfpf fuel pump, not a problems at all, tight fit but everything is like it should be 9/10

- FMIC fit well

- GC`s fitment is better than i expected, cast quality is much better than OEM or
that first upgrade 10/10

- Oil lines fitment was perfect, rear turbo water return line needed some few millimeters of bending to fit perfect, the line hit turbo chra clamp bolt, it`s possible to rotate it a bit but i decided not to cause it`s paint marked and i wasn`t sure about warranty if i broke that paint seal. 9/10

- Silicone inlets fit quite well, pain in the ass to torgue the clamp to turbo cause of short snout this sice turbos have but it fit. 9/10

- Hot side fit too, it was more my mistake cause i ordered a 2.5" version of it and vrfs has a 3" on it. hotside is "hitting cooler reservoir hose but space is limited on that position and i raised reservoit by 20mm to get enough space. fitment propobly 9/10

- Double barrel shotgun fitment was all most perfect, minor grind from bracket cause
of weld on shotgun bearing house weld hit the bracket, 20 second and issue solved ( Tony has done mods to future bearing houses). 9/10

- Modded fuel rail fit as oem, the shorter high pressure fuel line could be little longer, discussed about it with Tony. 9/10

- Water line rerouting could be better but that`s for sure something every single
installer must concern about them selves , fuel lines is the same, watch that they fit or reroute those to get fitment you are satisfied on. 6/10

huge amount of small pieces is to be checked not to hit anything cause
of very tight engine bay but got everything to fit to a level i`m satisfied on.

End conclusion

My opinion to a perfect assembly time of everything is on some 30 hours to get
a running car with all those mods and to be honest, it`s not ment for a average guy
to do at home without proper tools or resources.

I own few workshops and tool shop with huge warehouse of bits&pieces
so it`s not ever fair to compare me against average home builder on this
so it can be taught as "unlimited access to everything needed"

I must thank at the end of buildup VTT / Tony for customer service cause there was some issues on bank what caused troubles ( assume my mistake) and we have swapped some 100 emails where half was caused of that bank issue and every time weekend or not, email respond time has been umbelieveble fast ( okay, must undestand there is some 10 hour time zone difference on us).

then the bad news, i got the car running yesterday, not leaks, or other issues, not dme fault codes and then i go got at the same huge
traction issues, nothing to do with power, but to do with 15 cm of wet first snow
of the season what we got here yesterday too.

i will continue thread after i got car on dry tarmac and get it tested on street.

[nikitino25]

Sounds good man keep us posted....

[Sticky]

Hi, first posting on this forum so be gentle

It's a very nice crowd these days. Plus we all like build threads.

Will be interesting to see your results with the Shotgun as the people running it you can count on one hand. Looking forward to your feedback.

[135boost]

I don`t know about power levels on old setup but assume there was something around 470 rwhp and with that
tested the car for standing mile here on a no_fly_zone day and got 274kph with limp mode at last 200m and
1/4 mile totally unprepped airport runway 200 utog street tyre combo and got low 12s with 203 kph spinning wheels for first 170m

i did some calculations on that old turbo setup TTH540 and my best guess is that there was some intake manifild /exhaust manifold pressure relation of some 2.6-2.9 so there has been exhaust manifold pressures on some +60 psi levels and that is for sure problems on stock exhaust valve springs and for sure hurt performance.

that was at the beginning reason for free flowing exhaust to get rid of all extra exhaust back pressures.

Now when discussed with Tony i got logs from him with his record breaking 1/2 mile and on these GC:s there
should be about 1.5 as relation so turbo swap shaked away some 25 - 30 psi back pressure from me.

my history with turbos starts early as 1986 when i did my first ford escort mk1 turbo build and after that
there has been some modded turbos on every single verchile i owned except one opel omega with top of it
a yamaha R1 turbo motorcycle. on that there was a MCxpress turbo kit from sweden and only 14 psi of boost
gave that 2 wheeler quite unique performance levels, 240rwhp/175kg and what i really learned tohate is laggy slow spooling dyno queen as a daily drived machines, been there, seen that with GT45 ar 1.14 /t66 combo on a 2.6L 16 valve fully built volvo race engine.

so on this there was as option GC lite, GC , or some other manufacturers T16/19L to T19/HL combo and
or big single and my personal vote went to twins cause of of fighting lag issue. now my consern
about GC`s is that lag, remember i haven`t drive a meter yet with the car after turbo swap because of snow bur
what i have undestand on internet discussion, the lag on those is on decent level (on the edge i just tolerate)
those TTH540`s was on that lag on their own terrotory because of that small turbine wheel sitting on stock housing.

oh, about Shotgun, i taught it`s more common choise then, as safety of the engine on my opinion it`s better
to have one injector/cyl than multiple (except throttle body) where external injector fail blow engine with super lean on that 1 cylinder and lambda trying to trim every cylinders up without undestand there is a issue on only one injector.


now with the GC double barrel combo i`m after some decent 600rwhp/600rwlbs to start with, i will post first
feels of driving on it and my opinion about lag or other issues if there is something on it.

[135boost]

so, first feels on it, exhaust sound is more agressive, raceport BOW is keeping psiiuu sound at relatively low rpm`s
and i was supriced on positive pressures to build up so early. there is that 3 psi on 1700 and some 4 psi on 2000rpm but after that it start really to build boost, 2300 rpm some 11 psi so it overrun stock 8psi on some 2200 rpm so low down torque was smaller issue i tough`t it could be. i think 20 psi is pushed on some 3000rpm and then i have some idea of limiting torque like this
3500rpm 23 psi
4000rpm 23 psi
4500rpm 24 psi
5000rpm 25 psi
5500rpm 26 psi
6000rpm 27 psi
6500rpm 25 psi
7000rpm 23 psi

i think problems on those levels is to get clean logs to tune the car
without wheel spin or some other stupid erratic issues.

let`s see what happend

[Sticky]

now with the GC double barrel combo i`m after some decent 600rwhp/600rwlbs to start with, i will post first
feels of driving on it and my opinion about lag or other issues if there is something on it.

I'd definitely like to see some graphs.

Are you planning to hit the dyno?