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Data is starting to trickle in. A few customers that just got the full street kit for their 991.2 GT3RS, others that just sent us 100-200kph times with the kit installed.
I have a .1 RS in Toronto if y'all want some international testing
We do yes! We have the least data on the 991.1 RS although we have multiple installs and lots of anecdotes of the car really picking up power at speed.
happy to offer you the same deal as others. Shoot me an email at jamie@dundonmotorsports dot com and we’ll get it set up!
Jumped the gun a bit in my excitement, was comparing 60-130 data to 100-200km/h data and I should know better...
I have post data 100-200km/h which is 62-124mph, so not completely comparable to 60-130 and will just muddy the waters by comparing them. 3 991.2 RS performance packages got shipped this week, so we should start seeing their data trickle in.
Still room in the 991.2 GT3 for those curious...
Last edited by Jamie@dundonmotorsports; 10-01-2019 at 08:33 PM.
My MAXIMUM gains for any specific rpm, happened at about 4200 rpm, and were as follows:
Horse Power: approximately 30 gained
lbft of Torque: approximately 43 gained
(there seems to be a shallow dip in both between 3500 and 4800 rpm...the Dundon kit smoothed this out, creating the largest gains there)
Now, the PEAK gains (peak of each curve respectively) were as follows:
Horse Power, at about 8000 rpm: approximately 20 gained
lbft of Torque, at about 6000 rpm: approximately 15 gained
There are a few small areas along the curves where the Dundon kit was below the OEM kit, but a large majority of the curves show at least some gains. The pulls before install were done at about 50F, while the pulls done afterwards were done at about 40F, so maybe lower those gain figures by a couple of units each? Still quite good in my opinion. There was another GT3RS being run on the dyno when I picked my car up, having gotten an Acrapovic setup with catted side muffler delete headers and center muffler delete pipe (so, NO mufflers in the system), and seemed to gain about half of what I had gained, although it did sound glorious. I of course retain the OEM center muffler with the Dundon kit, so mine isn't that loud, but it's a definite improvement over OEM. The Dundon kit retains the valve functionality of course, but the sound delta and the sudden hit don't seem nearly as pronounced. It took about ten or eleven pulls on the dyno for the ECU to finish adapting and put out consistent numbers.
I will perform post-install 60-130mph tests with the Dragy unit, as soon as I get a day with temps similar to those that existed when I did the pre-install tests.
Solid gains christian! Cool you were able to hear the akra and Dundon setups in person back to back. You always have the option of adding the "loud" center exhaust later if you want more volume. what did you think of the difference in tone between the steel and titanium systems?
Solid gains christian! Cool you were able to hear the akra and Dundon setups in person back to back. You always have the option of adding the "loud" center exhaust later if you want more volume. what did you think of the difference in tone between the steel and titanium systems?
Yeah, that was a pretty cool circumstance. I just showed up to pick my car up, but I ended up hanging out for two hours watching them finish the Acra system and dyno that car.
Of course, I've retained the OEM Ti center muffler, although the rest of my setup is now Dundon's 321 SS. Along with being about 20% louder, my tone has changed ever so slightly. It isn't a lot, but I picked up more of that low base undertone at idle which I like a lot. I also picked up a bit more (not much, just a small increase) of the little pops/gurgles/growls that occur with shifts and/or quick changes of the throttle position. I don't think there is a lot of that to be had with the OEM tune, even with open pipes, because our engine is just sooooo smooth. I'm sure you could artificially increase it with a tune, but I don't really care about that. Although faint, I can now hear what little of it the stock engine does do.
I think actual TONE changes between all the various systems/configurations must be minor. I mean, it's still a smooth running, screaming, opposed six cylinder no matter what exhaust you put on it. Sure, you can get a little bit of difference with different sizes and bends and pipe volumes and materials, but mostly it's about how much of the engine's sound(s) you're corking or uncorking.
I say 20% louder, and that's a guestimate. I think the center muffler in the OEM system must be doing about 80% if the sound reduction (compared to open pipes). So losing the side mufflers loses 20% of the muffling total, if that makes sense. The actual number might be different than 20%, but my point is that it is NOT anywhere close to losing ALL the muffled effect, like that Acra system was, and like I'm sure mine would be if I threw in a center muffler delete pipe also. So the scale I'm using when I claim 20% is from the stock system volume up to the no-muffler-at-all volume. AND it's based on idle and small blips.
Once you get the engine screaming under load, I would say it's more like 50%. Like, it almost SEEMS as loud as the no-muffler system, but then you stand behind both while they're screaming, and you realize the no-muffler setup hurts your ears and you should have put on those hearing protection headsets over there on the table, you know?
Take the values with a grain of salt. This is not SAE corrected data. If SAE corrected I think the numbers would be a bit lower. And I tend to THINK the numbers are a little high because it doesn't look like the RPM was calibrated just right, since the cutoff reads at about 8900rpm instead of 9000rpm, so they might really be a bit lower because of that also. I am in discussions with my dyno guy and Dundon to sort of figure out how to evaluate...so again, take this preliminary graph with a grain of salt. But IF the numbers are right, it suggests I'm at just over 550 HP at the crank.
I may be wrong but wouldn't the delta be the same if it was corrected wouldn't baseline lose HP as well
Dyno’s need to be evaluated carefully. These two runs were ambient temps within 5-6F, 49-55F. So likely actua Intake temps are below where the cars ecu will intervene. This is also in the ball park of the numbers we see both for stock and for post install.
grain of salt always for dyno results and a little thought and understanding of the car has to be applied. We spend a lot of time using fans and blocking hot air from the radiators etc...
let’s see what Christian can muster on his 60-130’s (with traction off and pdk sport on!)
The last RS customer that sent data (Warmer temps and higher elevations) went from 10.16 sec before to 8.93 after.
had a touring today send data that was 9.78 sec before (lower elevation and cooler temps than the RS) to 8.98 after...
Last edited by Jamie@dundonmotorsports; 11-13-2019 at 10:07 PM.
I will report 60-130 Dragy results once I get a chance to perform the runs.
I will repeat the runs in exactly the same place, again in both direction, at a time when the ambient temp is close to what it was when I did the pre-install runs.
I will match the fuel level, fuel quality, tire temp and pressure, car settings and any other conditions, as precisely as I am able.
I intend to do it on over the weekend, if the weather cooperates.
My method before was to floor the throttle at 45mph and let the car run up to 140mph, to insure that the 60-130 was entirely captured with the car at full throttle and the PDK stabilized in its mission. I left the PDK in automatic mode, with PDK Sport turned on, and will do the same. I believe this is the best choice for consistency, since once stabilized with a purpose, it is so consistent with its shift points and shift timing. I feel that, as long as I get the weather close to what it was before, there should be no factors that anyone could bring into question.
I'm not really concerned about 0-60 and/or quarter mile times, because any run with a launch involved is less likely to be consistent, even with launch control. My pre-install 60-130 runs were 8.75s and 8.85s. That's one run in each direction. I did a few each way, and they were within a couple hundredths of those numbers. So I feel confident that the post-install 60-130 runs will tell the story.
You see the improvement between about 3500-4900rpm? The old butt dyno can definitely feel that. Like, if you're squirting around in the mid-range, with the PDK in manual mode, using the paddles (to keep the PDK from trying to downshift upwards out of that rpm range), you definitely feel the difference. Now, I know plenty of people have gushed over how good this system is, but let's be completely honest...it's not like you've suddenly slapped a turbo onto the car and gone from 500HP to 850HP. And it's not even like you've suddenly got VTEC Yo! where the power changes suddenly at a specific rpm. It's a mild and smooth, but certainly noticeable, improvement. It's great for what it is...a better exhaust and intake setup on what is already a great naturally aspirated car. As long as you don't have unreasonable expectations, it's excellent. If you DO have unreasonable expectations, I don't know what to tell you.
I haven't driven enough yet to evaluate the butt dyno in the higher rpm range. I guessing it might be hard to tell since everything happens so fast already when you've got the throttle floored and you're wringing the PDK out hard, but I don't know yet.
Do I think it's worth the money? Within reason, yes I do. I know it's expensive. But what else is on the market that will give us such gains for these cars? I would recommend this kit to anyone, within the bounds of reasonable affordability decision making practices, relative to your own financial ability.
And I might want to go louder. I'm now thinking I might want the Crack Pipe, keeping my OEM center muffler to swap in for the very rare occasion that I might be at a track with a sound restriction. Maybe. I'm going to drive it as-is for a month as then decide.
Hey Jamie, does the Crap Pipe have 2.5" main inlet, or 3"?
10-01-2019, 03:21 PM
