Accessport for GTS 4.0/GT4/Spyder
01-27-2023, 10:08 PM
#76
This fell off the map. Any feedback from anyone?
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c1pher (01-28-2023)
01-28-2023, 01:21 PM
#79
Burning Brakes
Did you check with Dundon to see if they have a custom tune for the GT4 with their headers/OAPs?
Of course, every car is a little different so, even if Dundon does have a custom tune, it may (or may not) require a little tweaking. Nonetheless, it might represent the best starting point . . . if Dundon has such a tune.
Avera
01-28-2023, 01:24 PM
#80
Instructor
Had it installed for a few months now. No issues so far. Paired with Soul OAP’s and BMC filters it has noticeably more power all through the rev range. Some people could say it disrupts the smooth power delivery of the stock calibration. But I like the punchy throttle response. To me it just makes the car feel a little more raw. Which is exactly what I want out of this car. Curious to see what a Pro-tune can do..?
01-28-2023, 03:14 PM
#81
Rennlist Member
@BabyNSX
Did you check with Dundon to see if they have a custom tune for the GT4 with their headers/OAPs?
Of course, every car is a little different so, even if Dundon does have a custom tune, it may (or may not) require a little tweaking. Nonetheless, it might represent the best starting point . . . if Dundon has such a tune.
Avera
Did you check with Dundon to see if they have a custom tune for the GT4 with their headers/OAPs?
Of course, every car is a little different so, even if Dundon does have a custom tune, it may (or may not) require a little tweaking. Nonetheless, it might represent the best starting point . . . if Dundon has such a tune.
Avera
The following 2 users liked this post by BabyNSX:
Avera (01-28-2023),
jdmporscheguy (01-29-2023)
01-28-2023, 04:19 PM
#82
Burning Brakes
I am in fact working with Charles at Dundon to develop the ProTune. As the AP is new for them (and everyone) and the 4.0L 718 ECU incorporates an entirely new engine management system, Dundon has to develop a new tuning strategy for these cars. I'll keep you posted of my/their progress.
Avera
01-28-2023, 05:25 PM
#83
Rennlist Member
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Avera (01-28-2023)
01-28-2023, 06:23 PM
#84
When I look at the torque curve, I don't see "punchy" either.
I do feel a big improvement in how quickly the car revs from 4k+ to redline. Maybe that's the punchy part?
01-28-2023, 06:31 PM
#85
Rennlist Member
You can always use the Accessport with the Stage-0 map which mimics the behavior and tuning of the stock ECU, plus you get the data logging capabilities. If you want to go for more power then you can go the ProTune route and have your tuner adjust the driving characteristics to your liking. Just a thought...
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Avera (01-28-2023)
01-28-2023, 08:19 PM
#86
Burning Brakes
You can always use the Accessport with the Stage-0 map which mimics the behavior and tuning of the stock ECU, plus you get the data logging capabilities. If you want to go for more power then you can go the ProTune route and have your tuner adjust the driving characteristics to your liking. Just a thought...
I admittedly carry pessimism when it comes to aftermarket tunes in the GT4
It seems Porsche squeezed just about all the juice out of the GT4 with the stock tune. The only meat left on the bone is what the EPA forced Porsche to take out with their exhaust setup
Of course, you already addressed the exhaust issue with your Dundon components . . . getting back what the EPA took out
As you know, I also have the Dundon components and (1) TQHP gains were impressive; (2) I do not need any ‘more’ for my purposes on the roadways; and (3) throttle responsiveness is about as perfect as I have ever experienced
What I am most interested to hear from your experience is (1) how much ‘more’ you can get with your specific (Dundon) setup from an aftermarket tune; (2) whether more equates to better; and (3) if the slide proves to be worth the climb?
The answers to these questions MIGHT be different according to your roadway and track applications? For example, a few more HP at the top of the RPM range is likely irrelevant for the roadways, but might equate to a small margin you are after on the track
Avera
Last edited by Avera; 01-28-2023 at 09:04 PM.
01-28-2023, 08:36 PM
#87
Rennlist Member
When I see what COBB was able to do safely with their Stage-1 tune on the GT4 at both 91 and 93 octane fuels (never mind the GTS which was so obviously restricted by Porsche) I believe there is still plenty of untapped potential in the GT4 with the Dundon exhaust (or any other similar setup).
For me the most interesting thing that I've learned by reviewing the COBB tuning guidelines for the GT4 and seeing my own data logs is that the car is always trying to maintain 14.7:1 AFR under pretty much all conditions and only lowers AFR to control exhaust gas temperatures. From what I could gleam from the tuning guides the trick to making more power with this engine is forcing the engine to target lower AFR under WOT. Typically engines make "Lean Best Torque" at 13.2 and best overall torque between 12.2-13.2 AFR. Porsche engines may want something a bit different, but 14.7 is almost certainly not where best power is made.
I think Porsche's aim for a super clean and fuel efficient car is what is driving this, not making absolutely the most power. Some evidence for this is how COBB was able to extract more from the engine by reducing AFRs.
Anyway... yeah the Dundon exhaust helps a lot, but I don't think that is the finish line if you want to extract more power from this platform.
For me the most interesting thing that I've learned by reviewing the COBB tuning guidelines for the GT4 and seeing my own data logs is that the car is always trying to maintain 14.7:1 AFR under pretty much all conditions and only lowers AFR to control exhaust gas temperatures. From what I could gleam from the tuning guides the trick to making more power with this engine is forcing the engine to target lower AFR under WOT. Typically engines make "Lean Best Torque" at 13.2 and best overall torque between 12.2-13.2 AFR. Porsche engines may want something a bit different, but 14.7 is almost certainly not where best power is made.
I think Porsche's aim for a super clean and fuel efficient car is what is driving this, not making absolutely the most power. Some evidence for this is how COBB was able to extract more from the engine by reducing AFRs.
Anyway... yeah the Dundon exhaust helps a lot, but I don't think that is the finish line if you want to extract more power from this platform.
@BabyNSX
I admittedly carry pessimism when it comes to aftermarket tunes in the GT4
It seems Porsche squeezed just about all the juice out of the GT4 with the stock tune. The only meet left on the bone is what the EPS forced Porsche to take out with their exhaust setup
Of course, you already addressed the exhaust issue with your Dundon components . . . getting back what the EPA took out
As you know, I also have the Dundon components and (1) TQHP gains were impressive; (2) I do not need any ‘more’ for my purposes on the roadways; and (3) throttle responsiveness is about as perfect as I have ever experienced
What I am most interested to hear from your experience is (1) how much ‘more’ you can get with your specific (Dundon) setup from an aftermarket tune; (2) whether more equates to better; and (3) if the slide proves to be worth the climb?
The answers to these questions MIGHT be different according to your roadway and track applications? For example, a few more HP at the top of the RPM range is likely irrelevant for the roadways, but might equate to a small margin you are after on the track
Avera
I admittedly carry pessimism when it comes to aftermarket tunes in the GT4
It seems Porsche squeezed just about all the juice out of the GT4 with the stock tune. The only meet left on the bone is what the EPS forced Porsche to take out with their exhaust setup
Of course, you already addressed the exhaust issue with your Dundon components . . . getting back what the EPA took out
As you know, I also have the Dundon components and (1) TQHP gains were impressive; (2) I do not need any ‘more’ for my purposes on the roadways; and (3) throttle responsiveness is about as perfect as I have ever experienced
What I am most interested to hear from your experience is (1) how much ‘more’ you can get with your specific (Dundon) setup from an aftermarket tune; (2) whether more equates to better; and (3) if the slide proves to be worth the climb?
The answers to these questions MIGHT be different according to your roadway and track applications? For example, a few more HP at the top of the RPM range is likely irrelevant for the roadways, but might equate to a small margin you are after on the track
Avera
Last edited by BabyNSX; 01-28-2023 at 09:02 PM.
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01-28-2023, 09:12 PM
#88
Burning Brakes
When I see what COBB was able to do safely with their Stage-1 tune on the GT4 at both 91 and 93 octane fuels (never mind the GTS which was so obviously restricted by Porsche) I believe there is still plenty of untapped potential in the GT4 with the Dundon exhaust (or any other similar setup).
For me the most interesting thing that I've learned by reviewing the COBB tuning guidelines for the GT4 and seeing my own data logs is that the car is always trying to maintain 14.7:1 AFR under pretty much all conditions and only lowers AFR to control exhaust gas temperatures. From what I could gleam from the tuning guides the trick to making more power with this engine is forcing the engine to target lower AFR under WOT. Typically engines make "Lean Best Torque" at 13.2 and best overall torque between 12.2-13.2 AFR. Porsche engines may want something a bit different, but 14.7 is almost certainly not where best power is made.
I think Porsche's aim for a super clean and fuel efficient car is what is driving this, not making absolutely the most power. Some evidence for this is how COBB was able to extract more from the engine by reducing AFRs.
Anyway... yeah the Dundon exhaust helps a lot, but I don't think that is the finish line if you want to extract more power from this platform.
For me the most interesting thing that I've learned by reviewing the COBB tuning guidelines for the GT4 and seeing my own data logs is that the car is always trying to maintain 14.7:1 AFR under pretty much all conditions and only lowers AFR to control exhaust gas temperatures. From what I could gleam from the tuning guides the trick to making more power with this engine is forcing the engine to target lower AFR under WOT. Typically engines make "Lean Best Torque" at 13.2 and best overall torque between 12.2-13.2 AFR. Porsche engines may want something a bit different, but 14.7 is almost certainly not where best power is made.
I think Porsche's aim for a super clean and fuel efficient car is what is driving this, not making absolutely the most power. Some evidence for this is how COBB was able to extract more from the engine by reducing AFRs.
Anyway... yeah the Dundon exhaust helps a lot, but I don't think that is the finish line if you want to extract more power from this platform.
If you come back and convey things are significantly improved, I know it wont be a vague statement like 'the drivability improved' that I hear all over this forum. Perhaps that is the best other owners can do to convey their satisfaction, so I do not mean to be too harsh.
Plus, if you are really satisfied, you will have done all the hard work for the rest of us with GT4s and Dundon components . . . we could just tell Dundon, give me the BabyNSX tune
Avera
01-29-2023, 03:50 AM
#89
When I see what COBB was able to do safely with their Stage-1 tune on the GT4 at both 91 and 93 octane fuels (never mind the GTS which was so obviously restricted by Porsche) I believe there is still plenty of untapped potential in the GT4 with the Dundon exhaust (or any other similar setup).
For me the most interesting thing that I've learned by reviewing the COBB tuning guidelines for the GT4 and seeing my own data logs is that the car is always trying to maintain 14.7:1 AFR under pretty much all conditions and only lowers AFR to control exhaust gas temperatures. From what I could gleam from the tuning guides the trick to making more power with this engine is forcing the engine to target lower AFR under WOT. Typically engines make "Lean Best Torque" at 13.2 and best overall torque between 12.2-13.2 AFR. Porsche engines may want something a bit different, but 14.7 is almost certainly not where best power is made.
I think Porsche's aim for a super clean and fuel efficient car is what is driving this, not making absolutely the most power. Some evidence for this is how COBB was able to extract more from the engine by reducing AFRs.
Anyway... yeah the Dundon exhaust helps a lot, but I don't think that is the finish line if you want to extract more power from this platform.
For me the most interesting thing that I've learned by reviewing the COBB tuning guidelines for the GT4 and seeing my own data logs is that the car is always trying to maintain 14.7:1 AFR under pretty much all conditions and only lowers AFR to control exhaust gas temperatures. From what I could gleam from the tuning guides the trick to making more power with this engine is forcing the engine to target lower AFR under WOT. Typically engines make "Lean Best Torque" at 13.2 and best overall torque between 12.2-13.2 AFR. Porsche engines may want something a bit different, but 14.7 is almost certainly not where best power is made.
I think Porsche's aim for a super clean and fuel efficient car is what is driving this, not making absolutely the most power. Some evidence for this is how COBB was able to extract more from the engine by reducing AFRs.
Anyway... yeah the Dundon exhaust helps a lot, but I don't think that is the finish line if you want to extract more power from this platform.
As someone who runs full dundon and has a custom "pro tune", I can without a doubt say one thing for certain: My GT4 is the farthest thing from being fuel efficient. Yeah sure, when I fill up, the car says "400 kms" at the top of fuel gauge, but I assure you, it's more like 250kms the way I drive. I went on 2 cruises and 1 cars and coffee event one week last summer and I filled up 3 times from Monday-Sunday lol so just be aware if you are running dundon + tune, don't look at your gas milage
Last edited by jdmporscheguy; 01-29-2023 at 04:00 AM.
01-29-2023, 09:19 AM
#90
Burning Brakes
As someone who runs full dundon and has a custom "pro tune", I can without a doubt say one thing for certain: My GT4 is the farthest thing from being fuel efficient. Yeah sure, when I fill up, the car says "400 kms" at the top of fuel gauge, but I assure you, it's more like 250kms the way I drive. I went on 2 cruises and 1 cars and coffee event one week last summer and I filled up 3 times from Monday-Sunday lol so just be aware if you are running dundon + tune, don't look at your gas milage
Avera
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