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- Dundon headers/OAPs weight reduction over OEM headers/OAPs: 8lbs
- Overall weight reduction: 30lbs**
** Please do not hold me to the ounce; confident in accuracy within (+/-) 2lbs
HP/TQ
- Butt-dyno supports JCR HP/TQ claims . . . no further comment
DISCUSSION
Anyone who has interacted with Jonny Cocker knows the pleasure. I have nothing but absolute positive regard for Jonny and my JCR purchase experience.
The developmental (70mm) Race Pipe produces the AMAZING TONE for which JCR is known to deliver. The Race Pipe has also taken the decibels to an INSANE level . . . and, arguably, the drone as well.
I am not a fan of the OEM valve control. The abrupt closed-to-open transition does not match the rising crescendo of a NA Flat6. The transition was exacerbated with the Dundon headers/OAPs, as decibels in the valve-open position were DRAMATICALLY increased over valve-closed position. Holding the valves open with a shaft collar was an ‘OK’ solution.
Jonny stated from the outset that the Race Pipe attenuates the ‘abruptness’ of the valve-closed to opened transition. I can confirm Jonny’s statement. The transition is subtle but still audible, but the acoustic response to throttle input is definitely more in keeping with RPM crescendo. In other words, the Race Pipe valve-closed position still generates considerable decibels.
MY drone tolerance is quite high but must admit my tolerance for the Race Pipe in the long run is going to be a matter of weighing tone/decibel enthusiasm vs. drone. The first time I drove the car after getting Race Pipe installed, I thought, ‘no way I can live with this drone.’ However, the drone bothers me less every time I drive, while the tone/decibels become more and more intoxicating. Part of the growing tolerance relates to the fact that I am almost always in PDK manual mode and learning to ‘drive around the drone’ to large extent. At this point I think I am safe in saying a manual or PDK manual mode are mandatory. Nonetheless, about the only time I am in PDK automatic mode is entering and exiting my neighborhood. The decibels are neighbor friendly but the drone is not so driver friendly.
While writing this review, I re-visited the @endurothread where he coupled his Dundon headers/OAPs with the 63mm Valved and Silenced Race Pipe. Not surprisingly, his comments were very similar to what I have experienced with the 70mm Race Pipe. What I have never forgotten is how @enduro GT4 sounded in his track audio . . . it has been burnt in my mind since the first time I heard it. The only GT4 audio I have heard that compares is @jdmporscheguy Crack Pretzel. Hence, my two considerations mentioned in the INTRO.
It seems the common denominator regarding the decibels and drone are the Dundon components. In other words, I do not believe the Race Pipe is inherently prone to excessive drone. Similarly, no exhaust I have heard on the market ALONE produces a dramatic increase in decibels.
Dundon aside, decibels and drone appear inherently linked when it comes to the GT4. Seems impossible to get a SIGNIFICANT boost in decibels without a similar degree of drone. Everyone will have a different threshold for the combination of the two. Trying to balance desired decibel levels with drone tolerance is the task. Throw tone preference into the mix you quickly understand why there are so many exhaust threads on Rennlist.
It is the aftermarket headers and, particularly, the OAPs that produce the decibels . . . and drone. In retrospect, the OEM rear box seems remarkably good at minimizing drone while letting decibels come through. Coupled with my Dundon Headers/OAPs, the OEM rear box delivered more decibels than I think most would desire, while producing a drone level I think most could tolerate. If not for the undesirable tone, I could have accepted decibels delivered with the OEM rear box.
Based on member feedback in numerous Rennlist exhaust threads, I believe MY current setup would be way too loud and the drone intolerable for the overwhelming majority. Conversely, I also SUSPECT the developmental (70mm) Race Pipe ALONE could be a great option for most in providing awesome JCR tone and providing a few more decibels than the 63mm Race Pipe . . . would also anticipate a bit more, but still quite tolerable drone level compared to the 63mm Race Pipe.
I SUSPECT the larger (70mm) pipe diameter of my Race Pipe is a primary contributor to the significant increase in decibels I experienced, as well as my butt-dyno observations with respect to HP/TQ. Air flow is a wonderful thing. The JCR design and construct materials (e.g., titanium) are the ‘special tone sauce.’
What I cannot reason out is the significantly increased drone I have experienced based on increased pipe diameter or JCR design. On one hand, unlike the 63mm Race Pipe, mine does NOT have a Helmholtz resonator. However, @enduro has the 63mm Race Pipe and experienced what he describes as ‘headache inducing’ drone. Again, I will defer to Jonny as to ‘why’ if he wishes to comment on the matter.
CONCLUSION
By adding the JCR 70mm Race Pipe to my Dundon headers/OAPs I experienced an incredibly racy/wailing tone and insane decibels, but significant drone tagged along with the all the glory. This setup is best reserved for those who frequent tracks without decibel limits and highly committed roadway drivers.
For those who have OEM headers/OAPs or some similarly well catted/resonated aftermarket setup, the 70mm Race Pipe MIGHT be a ‘goldilocks’ solution. Certain to deliver that incredible JCR tone; anticipated to strike a healthy and tolerable balance of increased decibels and drone. Up to Jonny to decide if JCR will ever make the 70mm Race Pipe routinely available? Like anything else, demand dictates the market.
Welp, you sounds like you got all the RSR but your hearing is decaying nicely so you're getting used to the drone
But seriously, and there will be various ppl chime in WRT legalities, running airpods with no music removes nearly all drone for me, so on certain long drives where I want to let the engine be in drone zone while cruising on the hwy, I'll run them.
WRT my drone, I'd definitely say it's more than most will want, but suspect mine'll be quite a bit less than yours will make, and mostly lives around the 1.8k to 2.5k RPM region. Above 3k and it's all music. You have my valved silenced pictured in between yours; the valved silenced appears to have quite a bit larger (that's relative as it's still very small) mufflers and due to an accidental experiment, I can attest to the effectiveness of the 1/4 wave resonators' contributions. IMO they effect a pretty noticeable change in tone.
Posted a pic in my thread for posterity, but I'll cross post here. Drive your car hard and the tips do this
As always, thank you for your input . . . greatly appreciated
I did not specify the 'drone' range' in my initial post because it seems to 'wander' a bit. It is not a simple matter of moving through a specific RPM range. For example, how much throttle is being applied when moving through a range.
All said, I can state the drone most consistently occurs between about 1K and 2.5K RPMs, and there seems to be a brief drone range that also exists just under 4K. I could try to better define the drone if anyone asks, but I do not have an impetus to do so otherwise.
Is worse than yours? I would have to drive in your car to know, of course. Regardless, I suspect most could not tolerate either yours or mine.
Your tips looks great
Now, if I could just figure out how to upload an audio file on Rennlist
Got it; I wanted to clarify as mine has a very specific RPM band where it drones. >3kRPM and I have no drone regardless of pedal position or load.
I'd help you with uploading a sound byte, but never figured it out for myself... I just upload to a third party vid site and link. Look forward to hearing yours.
Super insightful @Avera. Appreciate you posting the detailed review. I’ve been researching exhausts for my Spyder for over a year and still undecided on the right fit for me, but your feedback is very helpful. Thank you!
Thank you for posting. I am also looking for exhaust options and this is helpful. One question, if you disable the auto start/stop feature on the car, does the drone get any better? I noticed that it helps quite a lot with the stock exhaust.
This is awesome. I can't wait to hear it. Do you happen to have someone around you with the mini muffler tips? I've wondered with the little bit of extra muffling if it would move the drone range around. Could possibly make the trip to the track more bearable.
Super insightful @Avera. Appreciate you posting the detailed review. I’ve been researching exhausts for my Spyder for over a year and still undecided on the right fit for me, but your feedback is very helpful. Thank you!
I tried to remain objective, even though a lot of what is discussed is subjective
I think a good starting point is asking yourself what your priorities are? More volume (decibels)? Different tone? To the extent an exhaust setup can achieve, a bump in HP/TQ? How much drone can you live with?
If you are honest with yourself regarding what YOU want most and what YOU are willing to live with, there are numerous aftermarket options that seem to similarly offer all of the above to varying degrees. Still, finding that 'Goldilocks' solution four YOU starts with an honest assessment of the above questions.
Answering those questions will dictate which aftermarket components (headers/OAPs/rear section) you want to add and which OEM parts you want to keep (if any).
MY setup offers ALL of the above . . . I MIGHT have crossed the line in the pursuit of 'more'???
I am not typically a very compulsive individual, and will let a tincture of time guide my direction moving forward.
I will continue to try and be as honest with forum members as I am with myself.
Thank you for posting. I am also looking for exhaust options and this is helpful. One question, if you disable the auto start/stop feature on the car, does the drone get any better? I noticed that it helps quite a lot with the stock exhaust.
I cannot answer your question because I have never driven my GT4 without deactivating the auto start/stop feature. Perhaps I will test it out get back to you with my observations
Do you have a GTS/Boxter 4.0 or GT4/Spyder?
f my memory serves me correctly, I believe I read elsewhere in this forum that the GTS/Boxter inactivates one of its engine banks according to auto start/stop function? I do not think that is the case with the GT4/Spyder?
My recollection could be wrong, so please do not hold me to the statements.
This is awesome. I can't wait to hear it. Do you happen to have someone around you with the mini muffler tips? I've wondered with the little bit of extra muffling if it would move the drone range around. Could possibly make the trip to the track more bearable.
I cannot answer your question because I have never driven my GT4 without deactivating the auto start/stop feature. Perhaps I will test it out get back to you with my observations
Do you have a GTS/Boxter 4.0 or GT4/Spyder?
f my memory serves me correctly, I believe I read elsewhere in this forum that the GTS/Boxter inactivates one of its engine banks according to auto start/stop function? I do not think that is the case with the GT4/Spyder?
My recollection could be wrong, so please do not hold me to the statements.
Avera
I have a 2022 718 GT4. I received the car about a month ago and found it hard to believe that the car had such a different “constant” tone at the RPM range that everyone talks about. I started researching online and saw a couple of posts mentioning that disabling auto stop/start helped by preventing the the cylinder banks from disabling. Sure enough, it did the trick. I tested in both city and highway and worked flawlessly.
Since finding that out, I started to wonder how much different a lot of the GT4 exhaust reviews would have been if the reviewers would have turned off auto stop/start.
I did go out and leave the auto start/stop on, then turned it off after a period
I honestly could not tell any difference with regard to anything other than engine turning off at stoplights
Avera
Thanks for trying it out. I was hoping that it helped some. On the highway while cruising between 2-3k RPMs, when drone seems most noticeable, if I turn off auto stop/start, the tone changes completely in a better way. I have the stock exhaust… I wonder if that’s why it is noticeable.
This is awesome. I can't wait to hear it. Do you happen to have someone around you with the mini muffler tips? I've wondered with the little bit of extra muffling if it would move the drone range around. Could possibly make the trip to the track more bearable.
I have BC Fabs headers and oap which are similar to JCR and Dundon, and a Cargraphics muffler that I have to run quiet tips for certain tracks. It does work and allows me to pass sound, when I couldn't before and it doesn't seem to have any impact on drone. Honestly don't really notice any difference in noise level from inside the car.
10-08-2022, 09:40 PM
Dundon headers/OAPs and JCR Developmental (70mm) Race Pipe
