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I got my first track day in the GT4 in last Sunday. Leading up to it, it seemed like all things were stacked up against me. A week before the event the forecast was for 80% chance of rain, the day before I noticed a screw in the rear tire, and I live in an area where it would have been impossible to find a replacement tire. And on the eve of the track day I felt the flu coming on. But the weather turned out to be perfect. I was able to have the tire fixed and the adrenaline from the excitement kept the flu symptoms at bay until the end of the day.
Anyway, my impressions of the car. Overall about what I expected. The grip of the Dunlop tires is respectable. They do seem to take a few laps to get up to heat and grip. I'm used to NT-01's and Toyo RR's which only take about a lap or two to get grip. The balance of this car is phenomenal and I love that the traction control doesn't interfere too soon, but does so when things get dicey. In the M3 the traction control HAD to be off, it would interfere at about 80% pace, utterly useless.
I expected more under steer from all the things I read on the forum, but was pleasantly surprised that it isn't all that bad and I might not even do all that much now, as far as suspension tweaking goes. Maybe it's because I am not at the full pace yet. I am about 4 seconds slower than OrthoJoe on his all time best lap on that track (Thunderhill 3 mile), and still a couple of seconds away from my personal best in my e46 M3, but I attribute some of that lost time to the car being completely stock and it being my first day. The stock pads definitely leave some time on the table as I am used to more bite from a track pad, but I love not having to deal with the pad squealing when driving it on the street.
It seems to me that I have to alter my driving style with this mid engine beast a bit, especially in off camber turns, trail breaking is more sensitive. It's almost like I have to brake and get back on the throttle sooner to get the weight back to the rear, before it gets a chance to step out on me. Also, just in general, I need/should/can get on the throttle sooner and harder in this car, because it can, but I need to gain the confidence that it holds. I think that is where I am going to make up most of the time going forward.
I did notice the rear being unstable under high speed braking from the toe out issue on the rear suspension geometry. That is probably going to be the first thing I address. And the long gearing does bother me ever so slightly. Overall the lower gearing in the e46 M3 worked slightly better for this track, but I am sure on other tracks it could be an advantage.
Overall I am very pleased and happy I made the switch. So far so good ;-)
Glad to hear all went well and thanks for sharing your initial impressions! I'm taking my new-to-me GT4 to the track at the end of February and really looking forward to it. Coming from an F80 m3 and a track prepped e92 m3 prior to that.
Glad to hear all went well and thanks for sharing your initial impressions! I'm taking my new-to-me GT4 to the track at the end of February and really looking forward to it. Coming from an F80 m3 and a track prepped e92 m3 prior to that.
You wont be disappointed.I bet the GT4 is as fast stock, as your track prepped e92 M3, unless you went above and beyond and gutted it.
Nice! You guys are so lucky to be able to track year round! I came from a Z4Mc and had similar impressions once I got my GT4 on the track, totally different! I don't think I could go back now, mid-engine convert for life. With the BMW I always felt like I had to manage a disparate front and rear but the GT4 feels so much more cohesive and balanced.
Probably the biggest change for me was corner entry. First off, so much brake (PCCBs) it is ridiculous, the brake zones are so long now (relatively). Second, compared to the front engine car the GT4 just wants to dive into a corner and it can take so much trail braking I really had to reset my mind entirely for how I could approach a corner. It's kinda a weird thing to now be able to go so much deeper into a corner but really try do the opposite and set-up the corner earlier and get on the gas sooner than the BMW. Because I can trailbrake the GT4 so much harder than the BMW, for me there's been a learning curve to find that right balance - too much and I have to settle the rear, not enough and I have to fight understeer to get the car in. On a wet track this was really obvious, my first wet track session I was going sideways into every turn which was... interesting. With the BMW it seemed like a longer mid-corner phase where I couldn't trailbrake as deep into the apex and I also didn't have the traction to power out as early so I had to be a little more patient between entry and exit.
The one thing I miss is that the feeling of weight transfer onto the nose isn't as obvious as the BMW. I don't know if that's because there isn't a big heavy engine out front, electronic steering, electronic shocks, or I'm just getting old and slow but I definitely had a better sense of the grip front end. For example, on elevation transitions (ie transitioning to an uphill or coming off a downhill) in the BMW I could really feel the g's press the nose into the transition and know when I could take advantage of the extra grip but in the GT4 those transitions seem so much smoother and less obvious so there are some corners where I know the new GT4 is way faster but I have to work my way back to the same amount of confidence.
I can guarantee tracking your GT4 will be addictive...so get ready!
On the instability under hard braking it's a normal thing for this platform. You can dial some of it out by doing a correct alignment but you will need some parts, like rear toe arms and shims.
This instability comes from the toe change that happens on the rear when the suspension moves. I have found that TPC offset rear toe links to cure most of this problem and if you add the DSC module with a proper alignment it will be gone 100% and confidence goes way up to brake really late.
Besides that I would recommend doing as much track time as possible to get to know the car...you are going to love it!
Nice! You guys are so lucky to be able to track year round! I came from a Z4Mc and had similar impressions once I got my GT4 on the track, totally different! I don't think I could go back now, mid-engine convert for life. With the BMW I always felt like I had to manage a disparate front and rear but the GT4 feels so much more cohesive and balanced.
Probably the biggest change for me was corner entry. First off, so much brake (PCCBs) it is ridiculous, the brake zones are so long now (relatively). Second, compared to the front engine car the GT4 just wants to dive into a corner and it can take so much trail braking I really had to reset my mind entirely for how I could approach a corner. It's kinda a weird thing to now be able to go so much deeper into a corner but really try do the opposite and set-up the corner earlier and get on the gas sooner than the BMW. Because I can trailbrake the GT4 so much harder than the BMW, for me there's been a learning curve to find that right balance - too much and I have to settle the rear, not enough and I have to fight understeer to get the car in. On a wet track this was really obvious, my first wet track session I was going sideways into every turn which was... interesting. With the BMW it seemed like a longer mid-corner phase where I couldn't trailbrake as deep into the apex and I also didn't have the traction to power out as early so I had to be a little more patient between entry and exit.
The one thing I miss is that the feeling of weight transfer onto the nose isn't as obvious as the BMW. I don't know if that's because there isn't a big heavy engine out front, electronic steering, electronic shocks, or I'm just getting old and slow but I definitely had a better sense of the grip front end. For example, on elevation transitions (ie transitioning to an uphill or coming off a downhill) in the BMW I could really feel the g's press the nose into the transition and know when I could take advantage of the extra grip but in the GT4 those transitions seem so much smoother and less obvious so there are some corners where I know the new GT4 is way faster but I have to work my way back to the same amount of confidence.
Yes, we are lucky with the weather and being able to go to the track almost year round, but we do pay a price for it (coincidentally I refer to it as the weather tax).
Interesting observations on the trail braking. I guess it depends on the turns. The track I drove on has a two turns in particular (one off camber, and one going down hill right at the beginning of the turn), where I felt that I can't trail brake as much in the GT4, because the rear weight wants to push the back out. So I started to just brake earlier and tried to get on the throttle sooner to transfer the weight to the back more before the critical point is reached and that seemed to work. Which also tells me that I might just have to apply that technique in general. Meaning get on the throttle sooner. It's definitely something that is going to take time to reprogram, after driving front engine cars for 30 years.
I also observed in one of the elevation changes, that the GT4 seems much more planted. For those familiar with Thunderhill and the bypass, the GT4 seems much more settled there. I was still taking it easy (or about the same speed as I used to in the M3), but in the M3 I always felt like the rear was getting very light going over the top, and the GT4 seemed to still have some reserves, where I can go faster. I just didn't have the confidence yet. It will take time.
I can guarantee tracking your GT4 will be addictive...so get ready!
On the instability under hard braking it's a normal thing for this platform. You can dial some of it out by doing a correct alignment but you will need some parts, like rear toe arms and shims.
This instability comes from the toe change that happens on the rear when the suspension moves. I have found that TPC offset rear toe links to cure most of this problem and if you add the DSC module with a proper alignment it will be gone 100% and confidence goes way up to brake really late.
Besides that I would recommend doing as much track time as possible to get to know the car...you are going to love it!
Yes, I actually had already read all about that and the TPC offset rear toe links are on my short list of mods. I just wanted to get one track day under my belt without any modifications, to get a good base line. But what I had read was definitely confirmed about the rear instability.
Yes, I actually had already read all about that and the TPC offset rear toe links are on my short list of mods. I just wanted to get one track day under my belt without any modifications, to get a good base line. But what I had read was definitely confirmed about the rear instability.
So how does the DSC module help that?
The DSC basically converts the GT4 suspension to fully active using all the available sensors and data.....in the case of hard braking the car has a lot less front dive which in turn minimizes any toe change.
The car also feels a lot better and believe it or not it's more comfortable on the street.
The one thing I miss is that the feeling of weight transfer onto the nose isn't as obvious as the BMW. I don't know if that's because there isn't a big heavy engine out front, electronic steering, electronic shocks, or I'm just getting old and slow but I definitely had a better sense of the grip front end. For example, on elevation transitions (ie transitioning to an uphill or coming off a downhill) in the BMW I could really feel the g's press the nose into the transition and know when I could take advantage of the extra grip but in the GT4 those transitions seem so much smoother and less obvious so there are some corners where I know the new GT4 is way faster but I have to work my way back to the same amount of confidence.
I think it is the electronic shocks as opposed to a traditional coilover. In my Lotus, you feel the weight transfer all the time, including side to side, such that you can induce oversteer or understeer depending on how you manipulate the weight with the brakes and gas pedal. The same is generally true of the GT4, but the shocks mask it a bit.
I think it is the electronic shocks as opposed to a traditional coilover. In my Lotus, you feel the weight transfer all the time, including side to side, such that you can induce oversteer or understeer depending on how you manipulate the weight with the brakes and gas pedal. The same is generally true of the GT4, but the shocks mask it a bit.
Good point, never even thought about that. I suppose all this fancy software/electronic monitoring on the suspension, does "muffle the senses" a bit.
Originally Posted by jcorderojr
Congrats!
Thanks
Originally Posted by sunnyr
Great looking car!
I miss it, but glad to see it being used the way it was meant to be. Happy miles.
It's made for this type of stuff, and as much as I like to just pamper it and keep it as pristine as new, it begs to be used on the track from time to time. I already put over 1000 miles on it since I bought it from you ;-)
01-17-2019, 10:34 AM
First track day in the GT4 under my belt
