I was in Houston this weekend and took a couple hours out of my R/R to do some flow testing on a couple of parts.
Here's the setup:
**All parts were flowed at 28" H2O on all tests. All tests were performed on SF600 flow benches. A radius clay inlet was used unless noted otherwise. The heads are GN1 that are econo-ported and matched to a 1200 intake by Champion. **
INTAKE FLOW
1. Original Intake flow rates. Performed about 18months ago at Kim Barr Racing Engines in Garland Tx. 3.875" bore adaptor.
2. New flow rates. Performed in Houston Tx. 4.030 bore adaptor(Smallest size available).
3. As above with ported BGC intake. Port misalignment due to improper machining of manifold by BGC.
4. As above with no radius clay inlet on the throttle body flange. We removed it just to see.
5. As above with 65mm Accufab throttlebody. No clay radius.
6. Just for fun we did these also. Production GM 2.8l 60dg. v6 aluminum heads. Mild portwork. 1.7" valve. Additional porting, "full race", would increase flow rates.
..................1...........2..........3..........4...........5.........6
.100...........62.........60.........60........60.........59........68
.200..........128.......130.......130.......130.......128.......114
.300..........182.......186.......186.......186.......183.......163
.400..........216.......216.......210.......209.......210.......200
.500..........228.......225.......214.......212.......213.......218
.600..........228.......228.......220.......218.......220.......223
.700..........XXX......230.......222.......219.......222.......XXX
EXHAUST FLOW
1. Oringinal exhaust flow rates. Performed about 18 monts ago at Kim Barr Racing Engines in Garland TX. 3.875" bore adaptor.
2. New flow rates. Performed in Houston TX. Thermal barrier coating on chamber, valve face, radius side and port. 4.030" bore adaptor(Smallest size available).
...................1............2
.100...........51............47
.200..........106..........110
.300..........139..........147
.400..........164..........168
.500..........172..........176
.600..........177..........181
.700..........XXX.........184
Notes:
The GN1 ports created no air turbulence at any lift, intake or exhaust.
We believe the manifold port misalignment is responsible for the airflow drop from .400" and up on test 3. With correct port alignment we feel the manifold will produce no flow loss and produce the same flow rates as test 2.
The retainer contacted the guide just before .750", there was no increase in flow rate at this valve lift.
The oversize bore adaptor shows a greater effect on exhaust flow than intake flow.
It does not appear(my educated guess) as though a stock bore would shroud the 1.94" intake valve significantly.
We are going to make some more port modifications. We plan to reach the mid 250's on the heads alone with a minimum amount of material removal.The exhaust will be modified proportionately.
There is alot of room for improvement in the BGC manifold. We will fix the port misalignment, play with some epoxy and other ideas and hopefully get the manifold to pick up the head flow a couple cfm.
The 65mm throttle body will be replaced by a 70mm unit. The new throttle body and BGC bonnet will be heavily modified. After the TB and bonnet mods are finished we will balance the whole setup to within a couple cfm, throttle body to valve.
The 2.8l v6 head produced no air turbulence at any lift.
The 2.8 heads are from an 87 Cavalier z24 we were building for street/dragstrip/autocross fun. This car had great street manners with a 216/228 at .050" and .454"/.480" 108 lsa cam retarded 2 degrees. Excellent throttle response and great low, mid and top end power, for a 2.8l that is. Pulled much harder than stock from idle to 7k+rpm. Sold it to a friend.
Enjoy,
Chris S
Here's the setup:
**All parts were flowed at 28" H2O on all tests. All tests were performed on SF600 flow benches. A radius clay inlet was used unless noted otherwise. The heads are GN1 that are econo-ported and matched to a 1200 intake by Champion. **
INTAKE FLOW
1. Original Intake flow rates. Performed about 18months ago at Kim Barr Racing Engines in Garland Tx. 3.875" bore adaptor.
2. New flow rates. Performed in Houston Tx. 4.030 bore adaptor(Smallest size available).
3. As above with ported BGC intake. Port misalignment due to improper machining of manifold by BGC.
4. As above with no radius clay inlet on the throttle body flange. We removed it just to see.
5. As above with 65mm Accufab throttlebody. No clay radius.
6. Just for fun we did these also. Production GM 2.8l 60dg. v6 aluminum heads. Mild portwork. 1.7" valve. Additional porting, "full race", would increase flow rates.
..................1...........2..........3..........4...........5.........6
.100...........62.........60.........60........60.........59........68
.200..........128.......130.......130.......130.......128.......114
.300..........182.......186.......186.......186.......183.......163
.400..........216.......216.......210.......209.......210.......200
.500..........228.......225.......214.......212.......213.......218
.600..........228.......228.......220.......218.......220.......223
.700..........XXX......230.......222.......219.......222.......XXX
EXHAUST FLOW
1. Oringinal exhaust flow rates. Performed about 18 monts ago at Kim Barr Racing Engines in Garland TX. 3.875" bore adaptor.
2. New flow rates. Performed in Houston TX. Thermal barrier coating on chamber, valve face, radius side and port. 4.030" bore adaptor(Smallest size available).
...................1............2
.100...........51............47
.200..........106..........110
.300..........139..........147
.400..........164..........168
.500..........172..........176
.600..........177..........181
.700..........XXX.........184
Notes:
The GN1 ports created no air turbulence at any lift, intake or exhaust.
We believe the manifold port misalignment is responsible for the airflow drop from .400" and up on test 3. With correct port alignment we feel the manifold will produce no flow loss and produce the same flow rates as test 2.
The retainer contacted the guide just before .750", there was no increase in flow rate at this valve lift.
The oversize bore adaptor shows a greater effect on exhaust flow than intake flow.
It does not appear(my educated guess) as though a stock bore would shroud the 1.94" intake valve significantly.
We are going to make some more port modifications. We plan to reach the mid 250's on the heads alone with a minimum amount of material removal.The exhaust will be modified proportionately.
There is alot of room for improvement in the BGC manifold. We will fix the port misalignment, play with some epoxy and other ideas and hopefully get the manifold to pick up the head flow a couple cfm.
The 65mm throttle body will be replaced by a 70mm unit. The new throttle body and BGC bonnet will be heavily modified. After the TB and bonnet mods are finished we will balance the whole setup to within a couple cfm, throttle body to valve.
The 2.8l v6 head produced no air turbulence at any lift.
The 2.8 heads are from an 87 Cavalier z24 we were building for street/dragstrip/autocross fun. This car had great street manners with a 216/228 at .050" and .454"/.480" 108 lsa cam retarded 2 degrees. Excellent throttle response and great low, mid and top end power, for a 2.8l that is. Pulled much harder than stock from idle to 7k+rpm. Sold it to a friend.
Enjoy,
Chris S
