TDT

To my eye Dundon runners look to follow the form of the GT3(RS) style but they are Dundon unique and they are properly sized to fit directly without requiring adapters as per OEM GT3 RS runners.
The maths is all their own and also those runner have been designed to work with a stock sized plenum. IPD or Carrera S. I don’t know if a GT plenum would fit or work in the same
way?!
Also they are designed for use with their headers and the harmonics and pulses generated by that system.

We see that dundon have then created their own intake plenum for the 911 cars, that work with their runners for those cars also.

Principle objectives are all the same. Optimising/maximising volumetric flow rate for a given RPM.

d00d

Never mind what I wrote about GT3 plenum flip in the GT4, the plenum orientation is the same with the engine rotated 180 degrees between models.
Only reason I can see for the flip in ajw45's picture is not wanting to install the shorter starter to allow the small flap vacuum unit to fit underneath.

Martin Anders

Especially exciting to learn more from your phased test approach. @TDT Are you working with Jens in Germany?

Can someone chime in as to the pure parts cost of the 991.2 GT3 (RS) intake system with the two flaps in the plenum? anybody that has that installed?
@ajw45 - i understand you were quite happy with the 4.0 x51 - you had the street/race personality of the engine i am assuming? did you hear some feedback from people that have the street/track (more mid range torque) personality?

on my spyder i might actually be quite happy with the 4.0 and nice mid-range torque for street use mainly - could even lead to not needing the shorter gearing as i am assuming to have torque/pull from 3000 revs onwards.

TDT

Yep.

ajw45

For the RS intake you'll need to contact Deman (not sure who else does this) about the specialized parts to make the intake fit since it isn't a direct swap like 991s / X51 / 718cs intake. The bolt pattern of the GT3 runners don't match the 981 heads. That said, I bet the cost for the actual plenums from Porsche aren't that different but the CS part maybe a little harder to order since it's a motorsport part.

Yes! I love the character of my engine but it certainly isn't the torque monster it could be. At around 4-5k rpm when engine starts to get into the meaty part of the power band the sound changes from more exhaust bass into angry metallic chainsaw and that's when things start to really move. The torquier engines have no waiting for revs but don't have the build of power to redline so great responsiveness for everyday driving but imho not as exciting a ride when you have the space to wind it out. Actual performance is probably a wash between them. This is what's great about having a mod friendly platform, you can build your engine however you want it to be for your driving. For me, I'm happy having less torque gains under 5k rpm for just getting around town or on the highway in exchange for a ripping top end which feels special even if it's less often enjoyed. Obviously the right answer is go 4.5l and have both the low/midrange torque and the top end

Five12Free

if you need a donor block for your conversion, I got you covered

Martin Anders

Thank You @ajw45 for sharing your abundant experience. I am now pretty sure, that i will be happy with the more street/track optimized 4.0L with x51 heads, 991s intake + larger TB + 100 cell headers -> New point that comes up is a bit worry about the standard clutch slipping at 500NMs of torque vs the 420NM standard. @Warwick Morris mentioned he got clutch slippage as well on a heavily optimized 3.8 with catless headers and x51.
-> should i just try it out and see what happens or directly go for a better clutch? 90% spirited road use and around 3 DE trackdays annually.

TDT

If the engine + gearbox are coming out and being split anyway, it makes sense to do clutch upgrade at the same time. You won’t have to revisit it later on.
IIRC Warwick’s usage is mostly track and road rallye…

Jim Vinci

Which block is that I might be interested

Snowy999

Intake runners from Dundon for comparison

TDT

When is it going in?

TDT

My own car will be finished next week.

Martin Anders

great stuff - can you already share some insights? Did Jens manage to get the GT3 dual flap intake system to play nice with the GT4 ECU and produce the desired results?
or will you know that next week? keep us posted please

TDT

Initial dyno with 718CS intake was done last week... confirms what we have been saying about this solution.
Great linear power up to redline.... super smooth. Pretty flat torque from 2k to 8k.

GT dual flap plenum fitted with the 718CS runners, and M&M Muffler to replace Stock PSE.
So expectation is that the custom map here will realise and release the full potential.

I want to post all the info together once we have final results.

Martin Anders

so what you want out of the solution is more torque down low AND more max HP up high? so far it seems you are quite happy with linear power to redline and flat torque from 2k to 8k - just trying to understand the end goal(s).
Looking forward to the updates. thank you again.