TRAKCAR

Memo to self, I have a lot of business in the NW I need to visit ASAP....

d00d

Damn you Jamie, I have an infected finger from the sharp under tray when installing your headers last weekend.
Now I have to spend more time under the car!
The internal engine modifications would need to be done elsewhere though, but will have to go with the ~4.2L option, as I'm OCD about even numbers.

Jamie@dundonmotorsports

Anytime Peter! NW is great to come to in the summertime, is like Florida's winter!

We can just round down for you, 4.4L and change...

Earlierapex

How do you perform pressure wave tuning during development? Is it empiric (just keep changing lengths and testing power), or is there a science behind cylinder size, exhaust valve size, RPMs, total cylinders, etc. that allows you to predict an optimum? Are the exhaust gasses from one cylinder scavenging an adjacent cylinder? If so, how would you do it with a V8 where the firing order timing of the exhaust pulses is not balanced for each cylinder bank?

I reinstalled my Dundon 991 GT3 headers and can't get the CEL to go off (probably because I put the O2 wires in backwards at first, since fixed). Any tips?

RennOracle

On the Dundon Finger Follower Wear/Cam Wear Fix Update, would it be better to wait, see what are the changes in the new 991.2 gt3, see if the block is the same and use the solution applied in the 991.2 (new head mostly and internals with internal oil lines, if I'm not mistaken) and basically make a upgrade to a solved engine?

Or better, get the new 991 cup car engines and see what they done, apply to the 991.1 gt3 and RS and R, maybe develop on top of what they did. The finger follower design will always require rebuilds (same as bikes), so a new head altogether might be a better solution.

FJSeattle

Come next March and my building will be open.

Jamie@dundonmotorsports

There is a lot of math around port diameter, valve size, RPM you're looking to tune peak torque for. This is math that Charles has refined empirically and is based on a lot of SAE papers and studies by Gordon Blair (the god father of 2 cycle and 4 cycle engine modeling). In some cases one cylinder is scavenging the adjacent firing cylinder, and others where it's to the other bank, depends on RPM etc...

Is it a flat plane V8 per chance? Might be best to take this offline...

CEL Codes are best read to see what they are, not assumed... That said if you're pretty sure you know what it's from, disconnecting the negative battery terminal works in a pinch if you don't have a code reader. If you need a code reader, call the shop at 253-2OO-4454 and we can send you one for free since you're already a customer! Tell John I said it was cool...



We were designing the fix before Porsche announced they were going to the solid solution in the 991.2. We're certain our design is sound as some of the best minds in the valve train industry have been involved. We've looked at the current 991.2 parts catalogue (recently released) and it's not likely the heads or pieces will bolt to a 991.1, Cup engine is the same, won't bolt up. The finger follower itself shouldn't need to be replaced if there is sufficient oiling. Other marques have implemented similar designs and they don't need replacement...

porscharu

What type of purge/weld positioner setup do you use? You have a picture of a jig for tacking on the GT4 header page of your website. I would love to see a time lapse similar to the one below. Great product, and I respect you for using 321 instead of 304L.

Jamie@dundonmotorsports

I'll grab a pic of the purge setup. We're liking the FUPA Ar diffusers, Also have custom caps and Ar supply to shield the inside of the tubes...

Unfortunately no positioner yet, gotta pinch our pennies until we can get the one we want!

porscharu

They look similar to the gas saver setup form CK worldwide. Do you have problems using the large cup with tight access, or do you increase your stick out? With your ingenuity you could make your own positioner. Keep up the good work!

Jamie@dundonmotorsports

The Furick Cup is really good at directing the Ar quite a long way... Check them out if you haven't had a chance! Great customer service too.

RyanSD

About to do my first oil change on my RS. what do you guys recommend? I plan to track it later this year

Terry T.

Jamie,

Thanks for this thread--very good marketing idea. Speaking of marketing, I think you should choose some local guy who tracks, say, a 2009 Cayman S, and install a 3.8 9A1 as a test mule

Terry
Local guy who tracks a 2009 Cayman S

Jamie@dundonmotorsports

We like Amsoil for a lot of reasons, the European formula is Porsche approved, full synthetic

https://www.amsoil.com/shop/by-produ...?code=EFMQT-EA

For track cars with no cats, the race oil, RD-50 with higher ZDDP is our preferred go to.



Was asked to do it... can't claim it as my idea..

That said if you want more power, getting a bigger engine or making a bigger engine is pretty straight forward. Come on down and see us!

GTEE3

Jamie,
can you confirm the oil filter replacement for a '16RS?
I have Porsche # 9A110720391 Mahle OC 1049/1
thanks!