Inlet Port geometry - ZR-1 Net Registry Forums

tpepmeie · 01-10-2015

I have a first gen Indy racing league Aurora cylinder head laying around, and took the opportunity to make some intake port molds. It's an interesting comparison between these ports, which made circa 700 bhp with methanol (4.0 liters), and the LT5 ports.

first, look at the port angles. LT5 has significantly worse port to valve angle. The Aurora is very straight and tall. Look at the difference in valve stem length!

Aurora

LT5

Also notice the LT5 has a big dead space on the long side of the turn, or bowl area. This ideally should be filled, either welded or with epoxy, to keep the velocity high through that area. Not sure why we have that bulge.

Here is a good shot of the LT5's port to valve offset. I can only speculate that this was done intentionally to generate swirl motion in the charge. You can see the port makes a turn before the valve.

Another of the LT5, this time with both valves. You can see both ports make the turn toward the center of the chamber.

The Aurora port is totally straight.

01-10-2015	#1
tpepmeie Join Date: Aug 2005 Location: Fishers, IN Posts: 814	Inlet Port geometry I have a first gen Indy racing league Aurora cylinder head laying around, and took the opportunity to make some intake port molds. It's an interesting comparison between these ports, which made circa 700 bhp with methanol (4.0 liters), and the LT5 ports. first, look at the port angles. LT5 has significantly worse port to valve angle. The Aurora is very straight and tall. Look at the difference in valve stem length! Aurora LT5 Also notice the LT5 has a big dead space on the long side of the turn, or bowl area. This ideally should be filled, either welded or with epoxy, to keep the velocity high through that area. Not sure why we have that bulge. Here is a good shot of the LT5's port to valve offset. I can only speculate that this was done intentionally to generate swirl motion in the charge. You can see the port makes a turn before the valve. Another of the LT5, this time with both valves. You can see both ports make the turn toward the center of the chamber. The Aurora port is totally straight. Last edited by tpepmeie; 01-10-2015 at 08:55 PM.