My GT2 build over the last year
05-23-2012, 04:56 PM
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05-23-2012, 05:08 PM
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Peter, when is the OLOA schedule typically published?
I think that an autocrosser has a bigger advantage on the unknown tracks, but nothing can beat knowing the actual track.
As an example, my first day at Sebring, just over a year ago, I came to the track with experience from multiple tracks nationwide, and autocrossing for 10 years continuously, but zero track time at Sebring.
My first session on street tires, best lap was my first ever lap 2:30.430. On my 2nd session I went down to 2:24.368 on the same tires. On my third session I switched to Hoosier A6, and dropped to 2:22.901. Earlier this year on the same Hoosiers I ran a 2:17.5. I would say my lap times have dropped at least 8 secs since my very first day on the first session given equal tires. Make that a 3 OLOA laps and the difference is 24 secs, 24 secs moves me up or down significantly.
A good strategy is to show up to an unknown track, time yourself. Then get a coach and work with the coach at that specific track, compare the lap time difference, multiply by 3, and check where the experienced lap times vs. no-experience lap times would put you, based on the gap.
I think that an autocrosser has a bigger advantage on the unknown tracks, but nothing can beat knowing the actual track.
As an example, my first day at Sebring, just over a year ago, I came to the track with experience from multiple tracks nationwide, and autocrossing for 10 years continuously, but zero track time at Sebring.
My first session on street tires, best lap was my first ever lap 2:30.430. On my 2nd session I went down to 2:24.368 on the same tires. On my third session I switched to Hoosier A6, and dropped to 2:22.901. Earlier this year on the same Hoosiers I ran a 2:17.5. I would say my lap times have dropped at least 8 secs since my very first day on the first session given equal tires. Make that a 3 OLOA laps and the difference is 24 secs, 24 secs moves me up or down significantly.
A good strategy is to show up to an unknown track, time yourself. Then get a coach and work with the coach at that specific track, compare the lap time difference, multiply by 3, and check where the experienced lap times vs. no-experience lap times would put you, based on the gap.
05-23-2012, 06:39 PM
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05-23-2012, 07:02 PM
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05-30-2012, 01:31 AM
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09-14-2012, 02:45 AM
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Here's an update-
Swapped the H&R rear sway bar for a 997.1 GT3 bar. Had a day at Autobahn south yesterday working on car setup. Got the car to understeer finally, and with more shock tuning of the rear end the balance came back to neutral. The car is now nice and pointy with no nutty rear end looseness, back end follows the front now. This is on the 456/1313 rear springs and 342/685 fronts, so I know this combo from Ohlins works good.
Also figured out something that nobody has mentioned. Stability Control on the high HP cars really interferes with the ECM, causing rough engine output at almost all usable rpm points, throttle position, and speeds. Switching it off really helps smooth out the engine. It's extremely noticeable- Izzone drove my car at Road America a few months ago and even he mentioned how it was acting up. Once I turned SC off, a lap later the engine was running like a top! In my case I think the OEM SC parameters are so close to what my car produces under nominal load that it immediately retards ignition. This is undesirable for two reasons- first, you lose drivability from the misfiring and richness, and second, it builds a tremendous amount of heat in the engine when doing so. I'm in contact with Champion about this and hope to have a solution beyond the "turn SC off" answer. I didn't get a chance to test TC, but I have an inkling it also interferes with the ECM's ability to control the engine output properly.
Swapped the H&R rear sway bar for a 997.1 GT3 bar. Had a day at Autobahn south yesterday working on car setup. Got the car to understeer finally, and with more shock tuning of the rear end the balance came back to neutral. The car is now nice and pointy with no nutty rear end looseness, back end follows the front now. This is on the 456/1313 rear springs and 342/685 fronts, so I know this combo from Ohlins works good.
Also figured out something that nobody has mentioned. Stability Control on the high HP cars really interferes with the ECM, causing rough engine output at almost all usable rpm points, throttle position, and speeds. Switching it off really helps smooth out the engine. It's extremely noticeable- Izzone drove my car at Road America a few months ago and even he mentioned how it was acting up. Once I turned SC off, a lap later the engine was running like a top! In my case I think the OEM SC parameters are so close to what my car produces under nominal load that it immediately retards ignition. This is undesirable for two reasons- first, you lose drivability from the misfiring and richness, and second, it builds a tremendous amount of heat in the engine when doing so. I'm in contact with Champion about this and hope to have a solution beyond the "turn SC off" answer. I didn't get a chance to test TC, but I have an inkling it also interferes with the ECM's ability to control the engine output properly.
09-14-2012, 05:41 AM
#72
Nick,
The comparison is going to sound a little crazy but it isn't - but here goes. I use to own and built both a 500hp bigger turbos Audi 2.7 twin turbo S4 and also a Audi 2.7 twin turbo Audi Allroad. Stock these cars came with 250hp - the Allroad had double the OE hp with bigger turbos the S4 had even more hp with even slighly bigger Turbos. The S4 was my daly / fun track car set up with Ohlins, Guard LSD - everything. The Allroad was my 500hp kid hauler.
Here is the thing about SC/TC
The S4 from the factory by programming clearly had higher thresholds built in such that even with more HP than the Allroad the car could almost always run, even do some crazy stuff with SC still ON - the Allroad could not - it would constant come on even in normal driving, tires were more Allseason with less grip - so the only way to make the car not constantly bog down / cut throttle / apply brakes - was to run with SC OFF - if I was doing any aggressive type of driving at all - this included if I was on the highway doing 60mph and just wanted to floor it to pass a car - even at 60mph already, I could get SC flashing and I knew I was only getting half the power that I wanted - with SC OFF, the car would drive how I built it to drive.
So, 2 basically the same cars but the one with the more aggressive slip angles / tolerances built into the ECU made the car work - the other needed turning off.
The other lesson I learned was the S4 when tracked absolutely needed SC turned off - the car wouldn't work otherwise. I went through the Ohlins tuning as well including fitting a Guard LSD in the car where there wasn't one that came with the car + I converted the center torsion to a high bias torsion to send upto 80% of the tq to the rear wheels. It was this combo of the LSD, high bias torsion and 550hp that during cornering and slipping the car that the ECU was just not totally happy - I could do a lot but if I wanted the mechanical parts to work their magic I had to disable the SC. When i finally did, when my confidence in the car grew and I finally had my sways set properly with decent shock settings the car was awesome - I think I actually built a GTR 10 years befor Nissan did as the LSD with the high bias center torsen was able to send upto 80% of the power front or rear and that car got out of corners faster than anycar I've ever been in.
Anyways, I also ended up going another route as well - I had a track ECU programmed that dramatically lowered boost spikes and basically had boost slowly build from 12psi gradually to 22psi at redline - the car felt like a massive V8 naturally aspirated engine. The guy who programmed this was Tony of EPL - eplabs.net - he now has a much, much larger business and tunes some massive twin turbo Fcars, Lambos, R10s etc. I worked with Tony on this car to make it work on the track - ie slow ramping boost that you could mat the throttle at the apex like in a GT3 and there would be no boost snap during track out but it would build smoothly but quickly and the car was a rocket because it was smooth.
Paul
The comparison is going to sound a little crazy but it isn't - but here goes. I use to own and built both a 500hp bigger turbos Audi 2.7 twin turbo S4 and also a Audi 2.7 twin turbo Audi Allroad. Stock these cars came with 250hp - the Allroad had double the OE hp with bigger turbos the S4 had even more hp with even slighly bigger Turbos. The S4 was my daly / fun track car set up with Ohlins, Guard LSD - everything. The Allroad was my 500hp kid hauler.
Here is the thing about SC/TC
The S4 from the factory by programming clearly had higher thresholds built in such that even with more HP than the Allroad the car could almost always run, even do some crazy stuff with SC still ON - the Allroad could not - it would constant come on even in normal driving, tires were more Allseason with less grip - so the only way to make the car not constantly bog down / cut throttle / apply brakes - was to run with SC OFF - if I was doing any aggressive type of driving at all - this included if I was on the highway doing 60mph and just wanted to floor it to pass a car - even at 60mph already, I could get SC flashing and I knew I was only getting half the power that I wanted - with SC OFF, the car would drive how I built it to drive.
So, 2 basically the same cars but the one with the more aggressive slip angles / tolerances built into the ECU made the car work - the other needed turning off.
The other lesson I learned was the S4 when tracked absolutely needed SC turned off - the car wouldn't work otherwise. I went through the Ohlins tuning as well including fitting a Guard LSD in the car where there wasn't one that came with the car + I converted the center torsion to a high bias torsion to send upto 80% of the tq to the rear wheels. It was this combo of the LSD, high bias torsion and 550hp that during cornering and slipping the car that the ECU was just not totally happy - I could do a lot but if I wanted the mechanical parts to work their magic I had to disable the SC. When i finally did, when my confidence in the car grew and I finally had my sways set properly with decent shock settings the car was awesome - I think I actually built a GTR 10 years befor Nissan did as the LSD with the high bias center torsen was able to send upto 80% of the power front or rear and that car got out of corners faster than anycar I've ever been in.
Anyways, I also ended up going another route as well - I had a track ECU programmed that dramatically lowered boost spikes and basically had boost slowly build from 12psi gradually to 22psi at redline - the car felt like a massive V8 naturally aspirated engine. The guy who programmed this was Tony of EPL - eplabs.net - he now has a much, much larger business and tunes some massive twin turbo Fcars, Lambos, R10s etc. I worked with Tony on this car to make it work on the track - ie slow ramping boost that you could mat the throttle at the apex like in a GT3 and there would be no boost snap during track out but it would build smoothly but quickly and the car was a rocket because it was smooth.
Paul
09-14-2012, 06:10 AM
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Ha, what that really explains is why Izzone explained the ride the way he did. You can't drive around with traction control on in a boosted rwd car and expect great throttle response. That explains a lot, I was thinking the vgt turbos is were just show or he was tip toeing through the turns causing the lag. But on/off boost with a twitchy rear end and I can see why it scared him. Turns bring choked until the car felt he had enough traction. Car cann't beat a bad setupLol
09-14-2012, 07:08 AM
#74
Here's an update-
Also figured out something that nobody has mentioned. Stability Control on the high HP cars really interferes with the ECM, causing rough engine output at almost all usable rpm points, throttle position, and speeds. Switching it off really helps smooth out the engine. It's extremely noticeable- Izzone drove my car at Road America a few months ago and even he mentioned how it was acting up. Once I turned SC off, a lap later the engine was running like a top! In my case I think the OEM SC parameters are so close to what my car produces under nominal load that it immediately retards ignition. This is undesirable for two reasons- first, you lose drivability from the misfiring and richness, and second, it builds a tremendous amount of heat in the engine when doing so. I'm in contact with Champion about this and hope to have a solution beyond the "turn SC off" answer. I didn't get a chance to test TC, but I have an inkling it also interferes with the ECM's ability to control the engine output properly.
Also figured out something that nobody has mentioned. Stability Control on the high HP cars really interferes with the ECM, causing rough engine output at almost all usable rpm points, throttle position, and speeds. Switching it off really helps smooth out the engine. It's extremely noticeable- Izzone drove my car at Road America a few months ago and even he mentioned how it was acting up. Once I turned SC off, a lap later the engine was running like a top! In my case I think the OEM SC parameters are so close to what my car produces under nominal load that it immediately retards ignition. This is undesirable for two reasons- first, you lose drivability from the misfiring and richness, and second, it builds a tremendous amount of heat in the engine when doing so. I'm in contact with Champion about this and hope to have a solution beyond the "turn SC off" answer. I didn't get a chance to test TC, but I have an inkling it also interferes with the ECM's ability to control the engine output properly.
Nick The first who mentioned about the SC/TC issue in high hp cars was Toby RS tuning found out that 730hp is the limit for stock DME to work perfectly with all the other feutures of the car... Then the issue was brought up on 6speed and was not taken seriously by the Big HP Tuners out there..
09-14-2012, 07:10 AM
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Well, there's nothing to blame Izzone concerning setup- when he tried it I was complaining of snap oversteer, and little did I know about the rear bar issue on my car, since it was the same diameter as OEM (although considerably stiffer due to shorter leverage, which I later confirmed by physically measuring the two). I personally was leery of driving it without SC because of the handling issue, so I didn't think twice about it when Izzone left it on. At the same time, I don't expect Izzone, who is used to driving a NA car, to keep it above boost threshold all the time (3500rpm) so whenever it drops below that, it will have slight lag. For the record, the GT2RS has an even lower boost threshold which is pretty amazing!
FYI I can now set up the rear shock with much less rebound, and a lot more compression. The magnitude of change is 10 clicks compression/16 clicks rebound, both from full stiff (full closed valve), instead of 13 clicks compression/10 clicks rebound.
Now with the right set up I can work on the SC issue separately. It would never had occurred to me that the OE GT2 SC program was that conservative, but cycling through the SC several times at the track proved the issue.
Concerning the comparison with the Audi and GT-R... I understand what you are saying, however the Audi is a four door sedan with higher mass, and I'd expect it to have lower SC thresholds, especially compared to the GT2. Believe it or not, my R32 GT-R has much better SC and TC programming, and interferes less in the beginning, and more smoothly during actuation (which is why I never thought the SC in the GT2 was an issue, assumed it wasn't because of how well it worked in the Skyline). Coupled with some tricks learned from the Group A cars via Mr. Tamura (lead engineer at Nissan responsible for the Skyline GT-R) about setting up the ETS-C and alignment (set up car,and drive it, like a FWD car). In fact, to drive it fast you
NEED to induce the ETS-C to actuate so power goes to the front. FYI in the Skyline GT-R it is a misconception that up to 50% of torque gets transferred to the front- the actual value is based on torque split clutch pack setup, and OE setup is for up to 50NM of torque. Quite different!
FYI I can now set up the rear shock with much less rebound, and a lot more compression. The magnitude of change is 10 clicks compression/16 clicks rebound, both from full stiff (full closed valve), instead of 13 clicks compression/10 clicks rebound.
Now with the right set up I can work on the SC issue separately. It would never had occurred to me that the OE GT2 SC program was that conservative, but cycling through the SC several times at the track proved the issue.
Concerning the comparison with the Audi and GT-R... I understand what you are saying, however the Audi is a four door sedan with higher mass, and I'd expect it to have lower SC thresholds, especially compared to the GT2. Believe it or not, my R32 GT-R has much better SC and TC programming, and interferes less in the beginning, and more smoothly during actuation (which is why I never thought the SC in the GT2 was an issue, assumed it wasn't because of how well it worked in the Skyline). Coupled with some tricks learned from the Group A cars via Mr. Tamura (lead engineer at Nissan responsible for the Skyline GT-R) about setting up the ETS-C and alignment (set up car,and drive it, like a FWD car). In fact, to drive it fast you
NEED to induce the ETS-C to actuate so power goes to the front. FYI in the Skyline GT-R it is a misconception that up to 50% of torque gets transferred to the front- the actual value is based on torque split clutch pack setup, and OE setup is for up to 50NM of torque. Quite different!
Last edited by Nick Wong; 09-14-2012 at 07:26 AM.