Bimmerworld GT-More

[SYT_Shadow]

Really impressive lap guys, thank you for posting

It's great to see where one can take a street driven car. For a 50k car and 50k in mods, you have something that is insanely fast.

That you could spend 140k on a M4 GT4 and then another 50k on it to make it faster than the GTMore is obvious.

[mikerunt]

The biggest drawback for me on the M4 / GTS platform vs GT4 was the safety aspects and Motorsports ABS/DSC.

You’re likely coughing up another $30k for full cage, fire suppression, etc to truly make a stock M4 paridy to the GT4 from that POV.

Does everyone need a full cage and all that? Probably not. But if you’re putting lap times comparable to a GT4 it might be a good idea.

Want to race W2W and even some time trial? Full cage might be a mandatory.

GTMore is still undoubtedly and INCREDIBLE machine and program, but that was the ultimate kicker for me.

[E92inSG]

regular m4/ GTS vs GT4 is literally worlds apart.

I don't see how you can even consider driving a GT4 on the street cos it's not legal as well.

Check out the fuel cell on a GT4 lol.



There really is no easy way to "convert" a road car into a GT4

More detailed pics of GT4 here:
https://bringatrailer.com/listing/2018-bmw-m4-gt4-2/

[funk323]

GTMORE is forsale

https://www.bimmerworld.com/BimmerWo...-for-sale.html

[mikerunt]

There is at least 1 GT4 for sale at very close to $130k…this should be interesting

[SYT_Shadow]

Originally Posted by mikerunt

There is at least 1 GT4 for sale at very close to $130k…this should be interesting

just don't forget to add another ~$100k to the M4 GT4 purchase for an enclosed trailer and a tow vehicle, things the GTMore doesn't need

[4Y_stack_acceleration]

Originally Posted by mikerunt

There is at least 1 GT4 for sale at very close to $130k…this should be interesting

Not sure about the M4 GT4 specifically but my understanding was race motors typically have engine rebuild intervals of 50-80 hours which cost $20-30k a pop (maybe James Clay could confirm?). I've read that if you de-tune it a bit / limit top end of RPM, the life extends dramatically

Good datapoint from Apex Nuerburg where all of the mileage of their F80 taxis are spent driving the 'ring. They've had 2-3 S55 motors fail around the 35,000 mile mark (none from crank hub failures, and they don't upgrade the crank hubs), which on napkin math is about 400-450 hours of track time

Originally Posted by SYT_Shadow

just don't forget to add another ~$100k to the M4 GT4 purchase for an enclosed trailer and a tow vehicle, things the GTMore doesn't need

Driving a few hours to the track and back in bucket seats with 1,100 spring rates sounds pretty rough...

[SYT_Shadow]

Originally Posted by 4Y_stack_acceleration

Not sure about the M4 GT4 specifically but my understanding was race motors typically have engine rebuild intervals of 50-80 hours which cost $20-30k a pop (maybe James Clay could confirm?). I've read that if you de-tune it a bit / limit top end of RPM, the life extends dramatically

Good datapoint from Apex Nuerburg where all of the mileage of their F80 taxis are spent driving the 'ring. They've had 2-3 S55 motors fail around the 35,000 mile mark (none from crank hub failures, and they don't upgrade the crank hubs), which on napkin math is about 400-450 hours of track time



Driving a few hours to the track and back in bucket seats with 1,100 spring rates sounds pretty rough...

Gt4 class cars have oem drivetrains, so there's no difference there. When you get into the GT3 class cars, that is a different ballgame altogether. Note that gt4 class cars use 's' engines, whereas gt3 class cars use 'p' engines. $30k vs $130k, and then you also go from a stock dct in the gt4 class to a transaxle box in the gt3 class, etc etc etc.

We've been driving in bucket seats with high spring rates for years and years and so far have survived just fine. A few hours is unnoticeable, but earlier in the year when we did Road America, 1000 miles each way, that was a bit tougher, and still the worst part was dealing with exhaust drone.
A good damper manages very high spring rates just fine.

[mKilgore]

Seriously impressive lap times for a street car. Congratulations to the whole team, and especially Phil and James! In my opinion, besting a GT4 car by 2 seconds deserves a round of applause and high-fives all around! It is not as simple as just throwing power and aero at a car. You all have built a complete recipe for the F8X chassis that is mostly obtainable by many track-goers like myself. Sure, a built engine and a few other bits may be a little on the extreme side, but the majority of the modifications on the build list are exactly what I plan to do for my own build.

Keep up the good work, and release that fuel-starve solution already would ya?

[b_w.]

Special delivery today

[SYT_Shadow]

Those camber plates are serious business! Nothing to do with the regular ones available for this platform

[ninekrpm]

This will be fun

Congrats!

[M3SQRD]

Impressive job making a full weight F82 corner as well as a F82 GT4 thru slow, mid and high speed corners, and out drag the considerably lighter GT4 on the front and back straights at VIR. Sub 1:52 is a phenomenally fast time for a > 3900 lb car that’s still driven on the street with legal exhaust emissions in place. Congrats BW!

[4Y_stack_acceleration]

Originally Posted by JamesClay

Working to update the page. As tested:

• 1,100 front and rear, coiled over.
• 3914 setup weight (includes fuel and 85kg driver)

The updated GTMore page is great! Clearly lists all the parts added. Will be helpful to everyone as a reference guide for track mods.

I'm curious if y'all did CFD testing for the aero package (splitter + dive planes + wing) to measure the net downforce and center of pressure? I didn't know until recently that CFD testing was available to civvies - the owner of my raceshop did it for his track car.

[M3SQRD]

Originally Posted by 4Y_stack_acceleration

The updated GTMore page is great! Clearly lists all the parts added. Will be helpful to everyone as a reference guide for track mods.

I'm curious if y'all did CFD testing for the aero package (splitter + dive planes + wing) to measure the net downforce and center of pressure? I didn't know until recently that CFD testing was available to civvies - the owner of my raceshop did it for his track car.

CFD models and theoretical predictions require some form of correlation with real hardware and actual test data. Otherwise, it can be GIGO CFD predictions. You could certainly use CFD to trade design options relatively speaking but getting exact downforce levels and COP predictions isn’t easy. That’s why F1 teams still spend a huge amount of time and money on actual wind tunnel testing and correlation with CFD model predictions. CFD has come a long way in the past two decades and has allowed individuals to build and run their own CFD models but its development is always being advanced/improved. Same applies to FEA.