My M4 GTS build, GT3HNTR.

[Lienrocs]

Hey everyone,

I've finally completed a project car (maybe) and figured I'd share it with you all.

A little background on my GTS saga though:

I purchased my first GTS brand new and loved it to pieces except for one part, the color. I thought frozen gray was going to be awesome and it was for a little but the color started getting to me so I let it go with no intention of getting another one. However, a year went by and I missed the car more and more even though I had some pretty cool stuff to drive in the mean time, but I knew I was going to have to find another one.

Now comes my car. I found an Alpine White car local to me with 1300 miles on it and snagged it. I immediately got to work on it.

The first major change was swapping out the seats. As you all know, the stock North American seats just do not do the car justice. I picked up some Sparco QRT-C's on BK mounts, put a 6 point harness in the car and went to the track. The car worked surprisingly well right out of the box. It was ballistically fast, had great brakes and had tons of feedback and feel. The only real let down was the lack of tire grip from the stock wheel and tire combo.

However, I knew a few changes needed to be made. Track work on the CCB's seemed like I was just throwing money away so I picked up some AP Essex 9668/9449 brakes. They have been phenomenal on the street and track. However, I had no issues with the standard brakes so it was more of a long term investment rather than a performance upgrade. What the brakes did offer, however, was a lot more wheel options. I opted to go with my favorite wheel and an all time great, BBS E88's. I also bolted on the tire de jour, A052's. After trying several differnet tire sizes I ended up settling on 295/35 square tires on stagger 10.5/11.5 E88's.

The next big step was necessitated by my other BMW which had an Ohlins TTX set up put on it and was a game changer. I thought the GTS was supremely damped until I got my E92 back and within 15 feet I knew the GTS needed an upgrade. I picked up a set of Ohlins TTX from PSI, got them on the car straight away and went.... slower. The Ohlins set up, while theoretically superior, was lacking the correct set up. The spring rates were not right and the slammed ride height we all love just flat out didn't work. To remedy this predicament I did what everyone would do, go full spherical bearings on all the suspension. I figured if I have to change spring rates anyways which requires a full alignment I may as well really get my monies worth.

I got the full SPL catalog as well as Hotchkis sway bars, IRP lower control arm and bimmerworlds rear camber arm bushing kit to really complete the set up. This then led to another while you were in there issue. To get the rear bar installed you have to drop the sub frame and it just so happens you need to drop the subframe to install the Turner diff brace. I ordered the diff brace but deviated a little on the bushings. I daily drive my car so a major NVH increase would have been less than ideal. I got Powerflex purple diff bushings to pair with the diff brace and booked a time slot to finally get everything done and get the car working well.

There was still the elephant in the room that started me down this rabbit hole, though, getting the right spring rates. After talking to several people very familiar with the F8X platform it was decided to convert the rear to a true coilover to get the correct spring rate but more importantly the ideal spring length. 1400 pound springs are not easy to find in lengths that allow the suspension to really breath. The final rates we settled on are 900 front and 800 rear.

Getting the car corner balanced and aligned also had another pleasant surprise, low(ish) weight. My car came in at 3417 pounds (3617 with 200 pounds of driver ballast) with all fluids and 7/8ths of a tank of fuel.

I got the car back on track and was blown away. I crushed my PB at Chuckwalla (CW) running a 1:58.2 with a theoretical of 1:57.3. I think I have a 1:56 in me and I reckon if you put an actual driver in the car it would throw down a pretty dang impressive lap time for something that is comfortably daily driven exactly as it rolled down pit lane.

[Lienrocs]

Sorry about the lack of photo documentation. I forget to take pictures until everything is finished and then it's too late!

[Lienrocs]

A few more.

[SYT_Shadow]

That's sweet! Nice upgrades! I'm lusting after the GTS more and more as time goes on!

[Lienrocs]

Originally Posted by SYT_Shadow

That's sweet! Nice upgrades! I'm lusting after the GTS more and more as time goes on!

Thanks man! It's my favorite car I've ever owned hands down. I can't think of a better car, especially considering how relatively inexpensive they are right now.

[stevehifi]

any comments on ohlins ttx? what makes them better than kw 3 ways? I have kw gts coilover setup on my car and it was really good on track but terrible on street.

I drove a car with ohlins R&T and was not impressed at all.

[Lienrocs]

Originally Posted by stevehifi

any comments on ohlins ttx? what makes them better than kw 3 ways? I have kw gts coilover setup on my car and it was really good on track but terrible on street.

I drove a car with ohlins R&T and was not impressed at all.

The GTS KW's work really well on track but are pretty harsh on the street after the Ohlins. The TTX rounds out bumps really well. It soaks up things that you think are going to upset the car which actually did upset the car with the KW's on. It's like the car is driving on carpet. They're just flat out incredible, especially considering the spring rates. The car had better compliance on both street and track compared to stock.

[fanatic1]

Originally Posted by SYT_Shadow

That's sweet! Nice upgrades! I'm lusting after the GTS more and more as time goes on!

We have to join the GTS party, its growing on me too. Helps to see Lienrocs at the track with those E88s

[jpy1980]

Gorgeous car and great time at Chuckwalla! I love that track!

Quick Q though. You seemed to have changed out most of the major parts that made the GTS different from the regular F82. Obviously, you still have the engine power with water injection, hood, front splitter and wing, but would similar results be had with the f8x with your same mods? Just curious.

[stevehifi]

Originally Posted by Lienrocs

The GTS KW's work really well on track but are pretty harsh on the street after the Ohlins. The TTX rounds out bumps really well. It soaks up things that you think are going to upset the car which actually did upset the car with the KW's on. It's like the car is driving on carpet. They're just flat out incredible, especially considering the spring rates. The car had better compliance on both street and track compared to stock.

Very nice.. which camber plates are you running? I think the PSI kit comes with GC right?

The OEM TTX kit comes with Millway camber plates and 800#/1256# (divorced rear), looks like a bit lower than your setup but might be still good for track.

How many levels of rebound/comp adjustment? What do you run on street vs track settings?

Thanks,
Steve

[SYT_Shadow]

Originally Posted by fanatic1

We have to join the GTS party, its growing on me too. Helps to see Lienrocs at the track with those E88s

After this track season. If I could fit tires inside the car I'd already have a GTS. Now I'll have to buy a wheel trailer and carry that with the GTS.

[erictrainer]

This is awesome! Thanks for sharing!

[Vladiz93]

What Wing is that?

[Lienrocs]

Originally Posted by Vladiz93

What Wing is that?

It's the OE GTS board with fall line M235ir wing risers and M240ir end plates.

[Lienrocs]

Originally Posted by jpy1980

Gorgeous car and great time at Chuckwalla! I love that track!

Quick Q though. You seemed to have changed out most of the major parts that made the GTS different from the regular F82. Obviously, you still have the engine power with water injection, hood, front splitter and wing, but would similar results be had with the f8x with your same mods? Just curious.

I'm not sure, to be honest. The power delivery the GTS offers over the normal M4 makes it way easier to drive straight out of the box. I also kept the GTS knuckles rather than going the civic route. It took more work to figure out how to get all the new parts to play nicely but bmw spent lots of money on R and D for a reason on them so I'm guessing they contribute to the over all package quite a bit. My car was also way lighter than I was expecting. The only real weight savings came from the seats. Everything else that was swapped out is pretty close to a wash compared to the stock component that came off.

I think, based on seeing non GTS cars run silly lap times, anything is possible. The big thing that would be hard to replicate though, is the power delivery and consistent charge air cooling. I didn't see inlet temps over 90 degrees while on track and the way the GTS delivers power is radically different than the tuned F80 I've owned previously. It doesn't even feel like and S55.

[FormulaMMM]

3417! What lightweighting am I overlooking in your awesome writeup??

[Lienrocs]

Originally Posted by stevehifi

Very nice.. which camber plates are you running? I think the PSI kit comes with GC right?

The OEM TTX kit comes with Millway camber plates and 800#/1256# (divorced rear), looks like a bit lower than your setup but might be still good for track.

How many levels of rebound/comp adjustment? What do you run on street vs track settings?

Thanks,
Steve

Hey Steve,

Let me double check my notes on the damper settings and I'll get back to you. I do know I took some rebound out of and added compression to the rear.

So about spring rates, I went through half a dozen sets of springs including 800 fronts and 1300 rears and the car just didn't work. I'm not sure what lengths the ohlins factory set comes with but I couldn't find a rear spring long enough to get the rear end to work in the divorced set up. On the 1300 pound rear spring it was like a skateboard. It was really hard to drive at that ride height without any real suspension travel. I wish my car were a bit lower for style points but the way it drives more than makes up for it.

[Lienrocs]

Originally Posted by FormulaMMM

3417! What lightweighting am I overlooking in your awesome writeup??

I was blown away too. I was expecting closer to 3600.

I was trying to run the numbers myself. The seats are the big weight savings.

However, everything else, I don't think is that much lighter. I swapped the CCB's for irons so that's about a wash. The wheel/tire combo I'm running may be lighter cause the 666's are made of belt buckles but I have a heck of a lot of tire so I'm not even sure they're lighter. I do know the ohlins dampers are silly light. I'm not sure you could use the rear as a paperweight they're that light.

Maybe all the SPL arms add up to a bigger savings than I thought.

[FormulaMMM]

Originally Posted by Lienrocs

I think, based on seeing non GTS cars run silly lap times, anything is possible. The big thing that would be hard to replicate though, is the power delivery and consistent charge air cooling. I didn't see inlet temps over 90 degrees while on track and the way the GTS delivers power is radically different than the tuned F80 I've owned previously. It doesn't even feel like and S55.

It is freakishly cooled. Engine compartment wouldn't keep your hands warm on a cold day post-session.

No doubt you could extensively mod a F8X to be faster than a GTS, but as reliably with equal or more power? Unlikely.

And at GTS pace, that cage and the ability to run a 6 pt is indispensable. Wouldn't trade that for 2 seconds/lap in a standard seat & 3 pt.

[FormulaMMM]

Originally Posted by Lienrocs

I was blown away too. I was expecting closer to 3600.

I was trying to run the numbers myself. The seats are the big weight savings.

However, everything else, I don't think is that much lighter. I swapped the CCB's for irons so that's about a wash. The wheel/tire combo I'm running may be lighter cause the 666's are made of belt buckles but I have a heck of a lot of tire so I'm not even sure they're lighter. I do know the ohlins dampers are silly light. I'm not sure you could use the rear as a paperweight they're that light.

Maybe all the SPL arms add up to a bigger savings than I thought.

yeah, that's something. I'm at 3514 driver's side race seat, no passenger seat. A few other things chucked out https://f80.bimmerpost.com/forums/sh...00&postcount=8

Same brakes as you. Ohlins & SPL savings maybe, dang.

[SYT_Shadow]

Originally Posted by jpy1980

Quick Q though. You seemed to have changed out most of the major parts that made the GTS different from the regular F82. Obviously, you still have the engine power with water injection, hood, front splitter and wing, but would similar results be had with the f8x with your same mods? Just curious.

A friend took a similar route with his GTS. Suspension replaced with MCS 3WR, full SPL arms, brakes.
The GTS equipped like that is a better GTS. It still has aero, an engine that is water injected, CF hood for weight reduction and ventilation and other specific things like a different bushing in the rear suspension, different uprights. etc.

You can always mod car X to be faster than car Y. What Lienrocks has, however, is still a GTS while a normal M3 will always be a normal M3. For example, Lienrock's car is in an upwards depreciation slope vs downwards for most cars.

[Lienrocs]

Originally Posted by FormulaMMM

yeah, that's something. I'm at 3514 driver's side race seat, no passenger seat. A few other things chucked out https://f80.bimmerpost.com/forums/sh...38;postcount=8

Same brakes as you. Ohlins & SPL savings maybe, dang.

Let me do some more digging and see if I can find an answer. 👍