Johnny Five

Hey Jamie,

Thanks for the quick response earlier about the exhaust. I’m very interested in the whole setup - headers and side delete / airbox / big throttle body.

Are your dyno numbers with this setup with or without a tune? I want the HP but i’m concerned about modifying this very expensive motor. Who makes the throttle body assembly? Are they reliable? What are the chances of encountering a bad air to fuel ratio with this setup? Will the computer automatically adapt without a tune? If a tune is necessary can you give us some reassurance the A/F ratios will be correct and are there any conditions that would cause the A/F ratio to get dangerously out of line?

Looks like some awesome products. Thanks!

Jamie@dundonmotorsports

All dyno's are no tune, so no issue.

Throttle Body is an OEM VDO mfg part

ECU adapts automatically, so no chance of bad A/F ratio, No tune necessary and the car automatically adjust the fueling both actively and ongoing based on the MAP sensor in the manfold and the O2 sensors in the exhaust.

Z06

I am considering exhaust options, its either side deletes or headers with side deletes..... for those with the Dundon headers side deletes?

Stock system to quiet...how do you find it sound wise for street driving vs. stock?

When running up against other GT car's, is their a noticeable difference in acceleration?

Seth Thomas

I currently have the Dundon Street Headers on my car and installed them right before SmokiesGT last weekend. After spending a weekend in the North Ga mtns with the system I am glad I did the upgrade. No CEL, slightly louder than stock on the inside of the car with a nice "bark" under part throttle shifts, and definitely feel the better torque this exhaust produces. Install on it was easy and straight forward. Took me about 3 hours from start to finish on a lift and without removing the rear bumper. For street driving I think this system is spot on with what most people are looking for sound wise. It is not too loud with a sportier sound than the stock exhaust. With the valves open you can definitely hear a difference outside the car with them. Inside not as much as outside. Can't imagine my car without them.

Here is a video for you to see the difference:

Z06

Sounds great.. thank you.

horns

Has anyone combined the street headers with a sharkwerks center delete (particularly on a .2 GT3)? Does the center delete wipe out the low end torque gains? Are there drone issues?

Jamie@dundonmotorsports

Super loud, will drone as the valves don’t have a center muffler upper flow path to direct the flow to.

Others have done it that wanted a straight piped car.

JasonAndreas

Has it arrived yet? How many pressure sensors? What did you end up going with? Optrand/NI ADC/catools? tfx? kistler/avl?

Jamie@dundonmotorsports

It’s here, we’ve been transitioning my 991 GT3 for sale and prepping the 991.2RS to get at speed data for the airbox/93mmTB/center plenum.

We went with Xtreme DI’s 12 channel along with kistler/AVL sensors.

flsupraguy

Do you have any before and after results of the airbox/93mmTB/center plenum on the .1rs?

Jamie@dundonmotorsports

Not clean head to head data yet. Once we have my car instrumented we’ll be able to show the difference in manifold pressure at speed and show the benefits more clearly.

Ruri67

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Zaskar1972

Finially got around to putting the street headers on my 991.2 GT3. I cannot give a direct comparison to stock as I had the Soul side muffer deletes but from what I understand they offer little if any power improvement. I certainly did not notice.

The Dundon on the other hand are like a slap in the in the face. Cold tires, only 12.5 C here today, the traction control kicked in going from 1st to 2nd at 8000 RPM. Sport cup 2's. That never happened before. The Soul definetly improved the sound. The Dundon setup is a little louder and sounds much better IMO. Heading to Area 27 for Saturday and Sunday. It will be interesting to compare the straighaway speed.

Installation only took a couple of hours. I could not use my lift. A couple of small ramps and a creeper. I left the bumper cover and bumper on. It was a none issue with the side mufflers already removed. That said, you will need a good assortment of extensions, universal joints, ratchet lengths, and so on if you choose that route. I did the Soul with the bumper cover and bumper on as well. A pain to get the OEM side out but it is doable.

Thanks so much for the great product Jamie!

Anyone looking for Soul side deletes with the valves? PM me. I am not going back.

AnthonyGan

I got the air box, headers with the crack pipe!! Awesome setup! TEAM DUNDON

FourT6and2

Any performance info before/after for just the intake/plenum/throttle body on an RS?

I'm interested in doing this upgrade, but I don't have plans to touch the headers at this time.