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We executed the 1st of 3 Power Kit 981 swaps in Feb 2014, complete with manifold and were the first ones worldwide to bring it to existence. Furthermore the Power Kit 991 manifold was in my 981 for over a year and will be going back in my GT4 along with the 3.99L crank / stroker conversion.
The kit offering is the same from either shop so...
While I hope to achieve in excess of 475 I do not want to increase RPM levels. I have always been concerned about harmonics at high RPMS and given the reduced rev limit of the factory GT3 Cup motors when revised to 3.99L, i see no reason to try and spin the car higher than stock. I actually want to come down maybe 200 more RPM until i get on the race track with the car and start exploring higher levels. The dyno results show that there is not much power to be gained above 7K BUT that config lacks the ported heads and factory Power Kit manifold which are worth their weight in gold when trying to achieve HP over 7K RPM. They are just what the doctor ordered to help cure the elusive "porsche dip" that every single flat 6 motor makes at 7K. At the end of the day all i care about is trying to deliver reliability and something that behaves like a car that came off the assembly line. I don't want to speak for anyone but i guarantee that none of you want some temperamental race motor type thing in your fresh street car. I want it to be just like our daily driven 3.8L 981 and 987 swaps.
In case you haven't heard this today.. You're pretty awesome,
I've already begun hiding funds form the wife.. now for the car.. the wait continues.
We executed the 1st of 3 Power Kit 981 swaps in Feb 2014, complete with manifold and were the first ones worldwide to bring it to existence. Furthermore the Power Kit 991 manifold was in my 981 for over a year and will be going back in my GT4 along with the 3.99L crank / stroker conversion.
The kit offering is the same from either shop so...
While I hope to achieve in excess of 475 I do not want to increase RPM levels. I have always been concerned about harmonics at high RPMS and given the reduced rev limit of the factory GT3 Cup motors when revised to 3.99L, i see no reason to try and spin the car higher than stock. I actually want to come down maybe 200 more RPM until i get on the race track with the car and start exploring higher levels. The dyno results show that there is not much power to be gained above 7K BUT that config lacks the ported heads and factory Power Kit manifold which are worth their weight in gold when trying to achieve HP over 7K RPM. They are just what the doctor ordered to help cure the elusive "porsche dip" that every single flat 6 motor makes at 7K. At the end of the day all i care about is trying to deliver reliability and something that behaves like a car that came off the assembly line. I don't want to speak for anyone but i guarantee that none of you want some temperamental race motor type thing in your fresh street car. I want it to be just like our daily driven 3.8L 981 and 987 swaps.
Ya, What John said..
__________________
2016 GT4-R
Rick DeMan
DeMan Motorsport
Upper Nyack, NY
845 727 3070
Porsche Sales & Service
Porsche Race services and parts www.DeManMotorsport.com
Kidding, love 2 top shops catering to the Cayman Market like this.
The more data points the better, look forward to GT4 lap times dropping for years to come :-)
The week we have all been waiting for (myself mostly) is finally upon us. Today we are removing the GT4 motor from our car. The 3.99L bits are here along with the Cargraphic GT4 race manifolds, Cargraphic 12lb. lightweight flywheel, sprung hub clutch disc, ported 991 cylinder heads, X51 intake manifold, K&N filters and anything else of which i can think to bolt to this monstrosity! I will be posting photos, making comments and following up with a dyno run.
What are you going to do with the front of the engine? And by that I mean the crank pulley. If you're going to use a lightweight flywheel and not change anything with the crank pulley,won't you create engine vibrations that can eventually lead to failure in the bottom end?
I know Jose, I know! I am starting right now with the race headers because otherwise I will get arrested if i use race headers AND Cup mufflers!
Originally Posted by neanicu
What are you going to do with the front of the engine? And by that I mean the crank pulley. If you're going to use a lightweight flywheel and not change anything with the crank pulley,won't you create engine vibrations that can eventually lead to failure in the bottom end?
This is the same flywheel we ran on the race cars in 2010 and then we added the motorsport pulley kit that i R&Dd for RSS; their first iteration did not have a dampened crank pulley like the factory crank pulley so they revised it to include one based on my guidance. This combination of pulleys and lightweight flywheel has been tested through multiple race seasons, including the 24 hours of Daytona and at RPM levels up to and including 8125 RPM. I have no concerns about this package whatsoever.
Originally Posted by Ferrarisimo
I remain very interested to see the X51 (assuming it's the entire Power Kit) go into the GT4.
Lol..i bet. Rest assured, we have done 3 X51 Power Kit 981 swaps already and for 2 years I drove with an X51 intake manifold in my 981 street car. Ask ChrisF - He and Stephen were in my shop and saw my modified intake manifold. Of course they are sworn to secrecy but they can at least attest to the fact that it exists, has been modified and already fits. We don't play 3 card monte here!
Originally Posted by Rick DeMan
That thing is going to be a beast!!
Yes sir! The revolution is upon us!
Originally Posted by RealityGT
wow 12lb is dam light.. this thing will rev free!
That's the intention. Lots of people think flywheels are BS, some don't think they do much; i have seen the effects with my own eyes. It's all about A + B + C + D =
I know you guys don't like to throw numbers out there without solid info,but do you care to speculate what are the crank power levels that can be achieved with the 4L and the X51 pkg combined?
I know you guys don't like to throw numbers out there without solid info,but do you care to speculate what are the crank power levels that can be achieved with the 4L and the X51 pkg combined?
I figured that if we don't get to 475 you guys wouldn't want to talk to me anymore?!??
P.S. You have a 997.2 GTS too?! Hold onto that thing! That's one of the most underestimated track cars around!
01-15-2016, 10:05 AM
