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John,can we see a pic of the X51 manifold?
Thanks.
For the record, while this may be the first time this has been done to a GT4, it's our fourth for a 981.
991 Power Kit GTS / X51 Manifold
991 Cargraphic 981 GT4 "Race" Manifold
We are still buttoning things up. West Coast folks will be enjoying the startup as they get to work tomorrow. The boys are calling it quits for the day soon.
For the record, while this may be the first time this has been done to a GT4, it's our fourth for a 981. 991 Power Kit GTS / X51 Manifold 991 Cargraphic 981 GT4 "Race" Manifold We are still buttoning things up. West Coast folks will be enjoying the startup as they get to work tomorrow. The boys are calling it quits for the day soon.
Many thanks! That looks just awesome!
The stock GT4 manifold is plastic,am I correct? I just hate plastic!
Many thanks! That looks just awesome! The stock GT4 manifold is plastic,am I correct? I just hate plastic!
It is plastic, yes. The X51 manifold is worth it's weight in gold because the side intake runners have flaps in them; to make torque down low it uses smaller side runners and to make HP up top they slam open over 5K RPM. It's the reason the power curve is a staircase and the torque table is flat.
It is plastic, yes. The X51 manifold is worth it's weight in gold because the side intake runners have flaps in them; to make torque down low it uses smaller side runners and to make HP up top they slam open over 5K RPM. It's the reason the power curve is a staircase and the torque table is flat.
Oh I saw the flaps in the lower intake. You could see them in the 2nd engine pic you've posted. Of course you have to magnify the pic,but you know me by now,I'm nosy and curious. LOL!
I also studied the coolant bottle for clearance...we've discussed that previously,I am not expecting you to reveal all secrets.
Very well done! Too bad there isn't a clapping emoji.
Oh I saw the flaps in the lower intake. You could see them in the 2nd engine pic you've posted. Of course you have to magnify the pic,but you know me by now,I'm nosy and curious. LOL!
I also studied the coolant bottle for clearance...we've discussed that previously,I am not expecting you to reveal all secrets.
Very well done! Too bad there isn't a clapping emoji.
Not to worry, I had a coolant expansion tank made in Indy by some top level engineers and going forward, this will no longer be a concern for us or anyone. I used my existing prototype manifold to make it all work for this exercise but when the motor comes back out for the 3.99L, then the new coolant tank will go in.
Originally Posted by Bardman
Newbie question - why do the headers have those springs on them? What do they do?
When we raced these cars we found that the length of exhaust tubing added stress to the manifolds so Cargraphic was kind enough to re-engineer everything based on our input to add a slip-fit collector and springs so that the system had some flexibility and less rigidity.
Originally Posted by DeerHunter
Is there any benefit to doing just the manifold (without the ported X51 heads)?
Yes, the manifold does add power AND it allows for a nice torque curve BUT on the 3.4L it was a bit lost without any tuning. With tuning this manifold can produce power on any car but on a stock 3.4L OR on a stock GT4, it needs some file manipulation.
For the record, while this may be the first time this has been done to a GT4, it's our fourth for a 981.
991 Power Kit GTS / X51 Manifold
991 Cargraphic 981 GT4 "Race" Manifold
We are still buttoning things up. West Coast folks will be enjoying the startup as they get to work tomorrow. The boys are calling it quits for the day soon.
Damn that manifold looks big compared to the stock one
02-24-2016, 03:24 PM
