GTS twins: the GTMore journey

[SYT_Shadow]

Intro
We are finally doing a build thread! Hopefully this helps other F8X builds & M enthusiasts out there ��

The builds will mostly use BimmerWorld parts as well as some Slon Workshop sprinkled in here for good measure. BimmerWorld has been our go-to shop since we started tracking many years ago, and their advice has proved to be invaluable all this time.

"First Time Right" modifications are always what we look for. It takes a lot of time and money to correct equipment mistakes. BimmerWorld has kept us on the straight and narrow path for many years! The pace and punishment we put our equipment through has shown time and time again that what may work flawlessly for some does not work for us. This is applicable not just in the OEM space but also in the aftermarket world, where many times ‘upgrades’ have insufficient performance.

Some background
We're instructors with a few clubs and have tracked many different BMWs, most recently an E90 stroker and an F80 CS.

Our focus is a bit different than most. Where we live we cannot have a trailer/tow vehicle, so we require street legal cars and drive them to-from the track. We don’t allow the lack of a trailered, stripped out vehicle to stop us in any way.

We love the handling characteristics of M cars. They are forgiving and communicative and easy to drive fast, exactly what a non pro driver needs. That they are reliable and easy to DIY upkeep is an added bonus.

After a few years with our E90 & F80, we started to look at what was next. The G80 was released.
Not going to the G80 was a hard decision.

On one hand, it will be spectacularly faster than F8X generation cars

On the other, there are zero performance/track mods for it available YET (especially as of mid 2021 when the decision was made!), and we do not want to re-encounter the situation we had with the F80, where top shelf 'track prepared things' turned out to not really be so track proven

Instead, we went with the M4 GTS. A base M4 would be better value, but many things conspired in that direction:

M4 prices during COVID went nuts, but the fundamentals aren't there. Eventually the regular M4 will cost 15k like any previous generation M

GTS prices also went up, but have better fundamentals

And let’s not forget, the GTS already comes with lots of nice things:

Factory half cage
Factory ceramics which will look nice in our street E90 and E92 M3
Water injection to keep temps down
Slight power bump from the factory
CF vented hood. After having this on the CS we couldn't resist
Baby aero
GTS are easily found with full body PPF wraps, a must have for the track
Family Pride: The GTS was the ugly duckling of the BMW family. Idiots drove it and didn't like it. So, we'll take the ugly duckling (which is shockingly fast out of the box, see Shakedown results below) and forge it into a battle axe: achieving M4 GT4 levels of performance in a package that’s not only street-legal, but actually drivable 10+h to the track.

GTS1:


GTS2:




Disclaimer for the entire thread
High-performance driving and automotive modification carry inherent risks.
High-performance driving can be very dangerous and may result in injury or death. We make no representations or warranty about products protecting against injury or death.
Car modifications of any kind that facilitate high-performance driving may reduce or limit the life of your car and any of its wearable parts and could result in damage to the car. We are not responsible for damage of any kind

[SYT_Shadow]

Shakedown

There are big plans for the GTS1 & GTS2, but first let's shake them down!



For the first shakedown, only GTS1 was used together with the E90 and F80CS as benchmarks

GTS1 shakedown mods

Camber plates at -2.5
Girodisc iron conversion
10.5” ET40 square wheels
Hoosier R7 295/30 square
OMP HTE-400 seats and 6-pt harnesses
…stock everything else

Results:
VIR 02:02.4
WGI 02:03.7

The second shakedown was done just with the GTS2

GTS2 shakedown mods

Camber plates at -3
PFC Z54 front BBK that we adapted from the E9X car
AP RadiCal rear BBK
10.5” ET36 square BimmerWorld TA5R wheels
Hoosier R7 295/30 square
OMP HTE-400 seats and 6-pt harnesses
…stock everything else

Results:
VIR 02:02.1 without aero after splitter/lip failed during testing. So basically, no aero. Rolling lap achieved was 2:01.2

WGI XXXXXX

[SYT_Shadow]

Future Plans

The basic idea is to build two 'GTMores'. The GTMore project may have been inspired by our F80CS!

The main idea is a comprehensive revamp of the F8X into more of a track monster after the massive experience BimmerWorld gained by having five M4 GT4s in different race series (IMSA, SRO, etc)

Why the GTMore builds? Because they are thoughtful, in depth conversions for the F8X. We used to read about Schirmer goodies on the E9X platform, this will be more than that but on the F8X platform.

Main List of Upgrades:

Suspension: M4 GT4 style suspension with 11" or 11.5” square and 315 square tire clearance. MCS 3WR and 4WR dampers.
Control arms/bushings: roll center correction, full arm/spherical conversion as part of the suspension package
Sways: sways that actually fit the car. After damages from Hotchkis sways in both our E90 and F80, this is appreciated
Fuel starvation: addressing fuel starvation issues F8X Ms have at under half a tank when driving hard with sticky tires. This is important not only so one can start a session with less than a full tank but also because with more power, more than half a tank will be consumed per session. Stock is half a tank a session.
Oil supply: the F8X downgraded its abilities vs the E9X, going from a 1.4g rating in the E to 1.3g in the F. We still remember being upset about this when the F8X launched. BMW must have also been aware of the downgrade, as the GTS & CS went back to 1.4g by adding another 0.5L of oil, but can we take it higher still? The answer is yes. The regular/ZCP M has 6.5L, the GTS/CS has 7.0L, the GTMore will have 7.3L.
Axle positioning: the GTMore will come with its own carrier to improve the high axle angle that is a result of lowering the vehicle
Diff: the GTMore will come with an LSD package
Cooling: cooling will be addressed using the lessons learned in M4 GT4 endurance racing
Aero: monster aero that would make a M4 GT4 blush
Power: BimmerWorld is working on a specific turbo package, utilizing their relationship with Mitsubishi to develop an upgraded set of twins that retain the high end quality of the OEM turbo manufacturer. No rebuilt, core charge, pieced together system - A direct from the OEM supplier brand new system. This package is not on the market and will come with tuning for track use.
Brakes: with the F8X big boy kit, the Alcon-BimmerWorld package. Nickel plated for our cars.
DCT Pan: Slon Workshop DCT pan to increase cooling, add 1L of oil capacity and lower the suction point, preventing starvation in combination with the baffling. As a side benefit, it does not use a rubber gasket and attaches solidly to the DCT pan
Misc: Some choice Slon Workshop components

[RugbyBro]

Subbed - this is exciting! Especially the prospect of bespoke Mitsubishi turbos

[slcook54]

Awesome, looking forward to following the build. Any more detail on the turbo package? I'm pretty happy with the mid range but would love a bit more up top.

[NYG]

Yesssssssssssssssssssssssssssss. Dude, that livery is DOPEEEE.

[TR930]

BimmerWorld is working on a specific turbo package, utilizing their relationship with Mitsubishi to develop an upgraded set of twins that retain the high end quality of the OEM turbo manufacturer. No rebuilt, core charge, pieced together system - A direct from the OEM supplier brand new system. This package is not on the market and will come with tuning for track use.

Full Race did this.

[OG Shark]

Absolutely awesome SYT_Shadow - really looking forward to watching this come together! Such a great platform for a track build that retains friendly street manners - such easy speed compared to how hard you have to work for it to build it into the E9x. We have been looking for the right M4 to start our next shop race car after our experience with the M2C.

Very interested to see what BW comes up with on the turbos. We actually started the install of the Full Race turbos yesterday that TR930 mentioned. Also the oil supply & fuel starvation issues. The fuel starvation in particular is already a pain and we are also adding grip right now.

Love this Danny - know with you & your brother behind this its going to come out epic!

[SYT_Shadow]

Originally Posted by RugbyBro

Subbed - this is exciting! Especially the prospect of bespoke Mitsubishi turbos

I know!! Really exciting!

[SYT_Shadow]

Originally Posted by slcook54

Awesome, looking forward to following the build. Any more detail on the turbo package? I'm pretty happy with the mid range but would love a bit more up top.

Nothing yet. I'm not first on the list for power upgrades because the F8X has good power to begin with

[SYT_Shadow]

Originally Posted by TR930

BimmerWorld is working on a specific turbo package, utilizing their relationship with Mitsubishi to develop an upgraded set of twins that retain the high end quality of the OEM turbo manufacturer. No rebuilt, core charge, pieced together system - A direct from the OEM supplier brand new system. This package is not on the market and will come with tuning for track use.

Full Race did this.

No one said Full Race did not do something similar.

The package on the GTMores is not the Full Race one, which admittedly would be second on my list. The BW one is oriented to track use.

[SYT_Shadow]

Originally Posted by OG Shark

Absolutely awesome SYT_Shadow - really looking forward to watching this come together! Such a great platform for a track build that retains friendly street manners - such easy speed compared to how hard you have to work for it to build it into the E9x. We have been looking for the right M4 to start our next shop race car after our experience with the M2C.

Very interested to see what BW comes up with on the turbos. We actually started the install of the Full Race turbos yesterday that TR930 mentioned. Also the oil supply & fuel starvation issues. The fuel starvation in particular is already a pain and we are also adding grip right now.

Love this Danny - know with you & your brother behind this its going to come out epic!

The F8X generation is fantastic. I do have regrets leaving the E9X generation when seeing dogbone s car, but in the F8X getting power is simply easier. In the end, what tipped the scales is the GTMore package doesn't exist for the E9X.

Full Race would be my go-to otherwise and were recommended for track use by a tuner here over more popular options.

The oil supply upgrade stuff is already available and we've installed it. If 0.5L from the regular F8X to the CS/GTS gets us 0.1g more, an extra 0.3L should get us +0.05g more.
It's pretty good to see a wet sump system go from 1.3 to 1.45g! Consider even the new Z06 with its dry sump system only goes to 1.25g

We're really excited, maybe one day we'll all meet at VIR with Mr Bone as well, that would be awesome!


The idea of a 'package' that is already tested is very appealing. Someone else can do the shock/spring testing and validation: we want to use our track time going for the HPDE trophy!

[ninekrpm]

wow...very excited to read/learn more.

especially around the axle, LSD, and the turbo upgrades...

appreciate you sharing the story/experience

[OG Shark]

Originally Posted by SYT_Shadow

The F8X generation is fantastic. I do have regrets leaving the E9X generation when seeing dogbone s car, but in the F8X getting power is simply easier. In the end, what tipped the scales is the GTMore package doesn't exist for the E9X.

Full Race would be my go-to otherwise and were recommended for track use by a tuner here over more popular options.

The oil supply upgrade stuff is already available and we've installed it. If 0.5L from the regular F8X to the CS/GTS gets us 0.1g more, an extra 0.3L should get us +0.05g more.
It's pretty good to see a wet sump system go from 1.3 to 1.45g! Consider even the new Z06 with its dry sump system only goes to 1.25g

We're really excited, maybe one day we'll all meet at VIR with Mr Bone as well, that would be awesome!


The idea of a 'package' that is already tested is very appealing. Someone else can do the shock/spring testing and validation: we want to use our track time going for the HPDE trophy!

Exactly my thoughts on the F8x vs E9x - I enjoy the E9x more but the in the end the ceiling is just too low for me on the track to be able to race at the pace that I want to. Definitely not leaving the E9x behind on the track - just enjoy it too much to do that - but moving forward new in-house race builds will be F8x based. Still very excited to see where our E92 is at once it gets back out on the track though and will continue to keep trying to push that car faster.

I agree on the tested package aspect - it is very hard to beat that.

I needs that oil supply!!! Got into the 1.4s and then back to hard throttle when the fuel starvation kicked in too. She apparently doesn't like 1.3+.

Hopefully we can all make VIR happen next year... I know I'm the weak link in that but I'm really trying

[biofluke]

This thread is amazing.

Congrats to you and your bro SYT_Shadow !!!

[D_SheerDrivingPleasure]

SYT_Shadow Exciting project. With the CS you were transporting 6 spare wheels/tires to the track.

Curious how you plan to haul all of your gear with this car? Roof rack? Tire trailer? I have an image of you heading to VIR with a 55 gallon drum of distilled water strapped to your roof. Btw, is it possible to fill the injection tank with something with better cooling properties than water?

[SYT_Shadow]

Originally Posted by OG Shark

Exactly my thoughts on the F8x vs E9x - I enjoy the E9x more but the in the end the ceiling is just too low for me on the track to be able to race at the pace that I want to. Definitely not leaving the E9x behind on the track - just enjoy it too much to do that - but moving forward new in-house race builds will be F8x based. Still very excited to see where our E92 is at once it gets back out on the track though and will continue to keep trying to push that car faster.

I agree on the tested package aspect - it is very hard to beat that.

I needs that oil supply!!! Got into the 1.4s and then back to hard throttle when the fuel starvation kicked in too. She apparently doesn't like 1.3+.

Hopefully we can all make VIR happen next year... I know I'm the weak link in that but I'm really trying

the only solution right now for fuel starvation is to always run the tank above half. If it goes down a hair below half then it can starve.

I'm really looking forward to this. When we double up on the car and run the same car in two run groups, the fuel thing is a PITA!

[SYT_Shadow]

Originally Posted by biofluke

This thread is amazing.

Congrats to you and your bro SYT_Shadow !!!

thank you! The cars are still stock but you'll see their evolution with time! super excited

[SYT_Shadow]

Originally Posted by D_SheerDrivingPleasure

SYT_Shadow Exciting project. With the CS you were transporting 6 spare wheels/tires to the track.

Curious how you plan to haul all of your gear with this car? Roof rack? Tire trailer? I have an image of you heading to VIR with a 55 gallon drum of distilled water strapped to your roof. Btw, is it possible to fill the injection tank with something with better cooling properties than water?

We got a custom tire trailer for 8 wheels, that we may use for 10. The track stuff will go in the trunks/passenger seats. That's one of the next posts coming up
The next challenge is getting the trailer hitch designed for the F80 to work on the F82, this promises to be fun. We'll start working on that this weekend

It uses one tank of water per tank of fuel at the track. This past weekend we went through 8 gallons, so it's not a huge deal. We haven't tried something else, like meth, but we'd rather let someone else experiment with that. High school is a long ways away but I seem to recall water has the best evaporation cooling properties per gram of weight

[alpinefd]

for the 7.3 liter engine oil, is there any change to the oiling system needed? or simply fill the stock system higher with 7.3liter of engine oil?

The slon parts looks very interesting, but where can you order them now? does bimmerworld offer those parts?

[SYT_Shadow]

Originally Posted by alpinefd

for the 7.3 liter engine oil, is there any change to the oiling system needed? or simply fill the stock system higher with 7.3liter of engine oil?

The slon parts looks very interesting, but where can you order them now? does bimmerworld offer those parts?

No internal changes needed. Basically it's a sensor+spacer package.
There aren't internal changes, so the new sensor reports 'full' when the car has 7.3L instead of 6.5L.

The slon stuff is really interesting, more to come there soon

[alpinefd]

this sensor + spacer idea is great !
https://www.bimmerworld.com/Engine/B...M3-M4-S55.html

Bimmerworld really needs to create a section for these trick products. It's really hard to find these in their 150pages of catalog pages.