Exhaust combos and Horsepower gains
02-05-2024, 12:35 AM
#1
Exhaust combos and Horsepower gains
Hello everyone,
Looking for some input on the subject. Today a friend and I, that have different exhaust combos, swapped cars to see the differences.
GMG WC-EVO Long Tube Headers + Soul Modular Side and Center Muffler Delete VS full Dundon street headers/lifetime muffler package.
The following were the conclusions we came up with:
The GMG Combo- the car revved more freely. It felt slightly less powerful in the midrange, but about the same in the top end as the Dundon. The Dundon felt more stout without a doubt but, it did not rev as freely. Where things got interesting is we lined up the cars and they were 100% dead even. My friend in with the GMG combo says that he also ran a stock gt3 and they were also dead even.
We want to find a pdk gt3 in IL 991.2 that is stock so we can do a dyno run of all 3 cars, possibly a vbox(if we can get our hands on one), and some rolling runs as well. We want to do this all on the same day and report back.
My honest guess is that all 3 cars will be dead even, but interested to see what the dyno sheets say. If you have any input on the subject let us know
Looking for some input on the subject. Today a friend and I, that have different exhaust combos, swapped cars to see the differences.
GMG WC-EVO Long Tube Headers + Soul Modular Side and Center Muffler Delete VS full Dundon street headers/lifetime muffler package.
The following were the conclusions we came up with:
The GMG Combo- the car revved more freely. It felt slightly less powerful in the midrange, but about the same in the top end as the Dundon. The Dundon felt more stout without a doubt but, it did not rev as freely. Where things got interesting is we lined up the cars and they were 100% dead even. My friend in with the GMG combo says that he also ran a stock gt3 and they were also dead even.
We want to find a pdk gt3 in IL 991.2 that is stock so we can do a dyno run of all 3 cars, possibly a vbox(if we can get our hands on one), and some rolling runs as well. We want to do this all on the same day and report back.
My honest guess is that all 3 cars will be dead even, but interested to see what the dyno sheets say. If you have any input on the subject let us know
02-05-2024, 01:24 AM
#2
I would like to add that this is not for any bragging rights haha. We want to find out if these mods make the claimed figures they do and to see how that translates into the real world for the sake of science.
JD
JD
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gt3991.2 (02-05-2024)
02-05-2024, 07:45 AM
#4
Rennlist Member
02-05-2024, 11:55 AM
#5
Yes we will make this as objective as possible and we will use a VBOX! We want to take driver skill out of the equation. That's why we only want PDK cars, driven in automatic and all same car settings. Should be a very good way to discuss the facts about these parts. Again we aren't trying to bad mouth any companies, but we want to see if spending $10-$20K on exhaust set up is truly worth it beyond the sound aspect. I feel the forums lovessss to argue about a specific company just based off of website data. Let's do some tests and discuss haha!
JD
JD
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gt3991.2 (02-05-2024)
02-06-2024, 04:45 PM
#6
Rennlist Member
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Dundon has a lot of dyno data to make their claims. I have not seen much from others, but I have not looked real hard either. That being said I took mine off my .1 when I sold it and drove the car on back to back days. You could never convince me there is no difference. Seat of the pants testing was conclusive 
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gt3991.2 (02-07-2024)
02-07-2024, 12:07 AM
#7
I have the dundon and I completely agree with you. It feels significantly faster, especially midrange. What was mind blowing is going against a gt3 that felt slower and we were dead even. This is why i would like to get 3 cars dyno'd, vbox and ran against each other.
My honest guess is that they will all be the same speed wise.
My honest guess is that they will all be the same speed wise.
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02-07-2024, 04:59 AM
#8
Instructor
One guy fitted a dundon street system with stock rear box too a 991.1 (these don't have the overall gains the 991.2 has according to dyno plots) and said he was 3km/h faster to the end of a straight. Let's face it, 20 bhp extra on these cars will probably make a couple of tenths difference 100-200 km/h.
Where the Dundon helps most is the torque under 5k.
Where the Dundon helps most is the torque under 5k.
02-07-2024, 03:56 PM
#9
Track Day
I’ve got a stock 991.2 pdk car in the northern burbs of Chicago. Also have a dragy. Happy to be a test subject, plus I want to hear the two setups. Been debating what to do with my exhaust
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gt3991.2 (02-08-2024)
02-08-2024, 12:21 AM
#10
Awesome! lets get errrrrrr done! PM me your phone number I will get you on a group chat so we can set it up!
02-11-2024, 11:12 AM
#12
Rennlist Member
In my not entirely dissimilar topic I posted Dragy 60-130 data with and without Dundon (and those combos with and without ECU tune)
I did not find a significant time drop with the Dundons. Extremely surprised and need to think about possible reasons.
https://rennlist.com/forums/991-gt3-...l#post19273054
I did not find a significant time drop with the Dundons. Extremely surprised and need to think about possible reasons.
https://rennlist.com/forums/991-gt3-...l#post19273054
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gt3991.2 (02-14-2024)
02-11-2024, 11:35 AM
#14
Rennlist Member
This data is valid only in these conditions - fresh air, low alt and good fuel. If you're somewhere in the US with high temps and p*** for fuel maybe opening up the exhaust might make a bunch of power as the stock ECU will have an easier time holding the ignition timing etc.