224 228 XER Cam and 1.8s
08-14-2007, 08:02 PM
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224 228 XER Cam and 1.8s I have a 224 228 XER Cam 114 LSA installed at 113 ICL , it has Dart 225 heads and 0.040 cometic gaskets. Im currently using 1.7 YT ultralight rockers. Im wondering if its possible to use 1.8 YT rockers with my setup - clearance seemed to be OK??
What do people think? Has anyone tried 1.8s on a XER cam to good effect.
The total lift would become 0.615 and 0.623 lift.
What do people think? Has anyone tried 1.8s on a XER cam to good effect.
The total lift would become 0.615 and 0.623 lift.
08-15-2007, 11:23 PM
#2
Originally Posted by oztrack
I have a 224 228 XER Cam 114 LSA installed at 113 ICL , it has Dart 225 heads and 0.040 cometic gaskets. Im currently using 1.7 YT ultralight rockers. Im wondering if its possible to use 1.8 YT rockers with my setup - clearance seemed to be OK??
What do people think? Has anyone tried 1.8s on a XER cam to good effect.
The total lift would become 0.615 and 0.623 lift.
What do people think? Has anyone tried 1.8s on a XER cam to good effect.
The total lift would become 0.615 and 0.623 lift.
08-16-2007, 06:34 PM
#5
1.8 is overkill unless your using sheet metal intake
Originally Posted by Patrick G
It's not cheap, but if done right, it can be very streetable. Here is the list of components to address in order of importance:
Head flow
Compression
Camshaft selection
Exhaust selection
Intake manifold selection
Valvetrain geometry/stability
Finding lost hp mods
Head flow:
Contrary to popular belief, when running a plastic intake manifold on an LS1, airflow at .600" is virtually meaningless. There are several reasons why. First, an LS6 intake will start to lop off airflow above 265cfm. A stock FAST 90mm intake seems to lop it off around 275cfm and a ported FAST 90 seems to lop off flow above 280cfm. What all this means is that most all airflow gains above 280cfm will go un-noticed when you bolt a plastic intake up to it. The real trick is to pack in more airflow in the low and mid lifts. If you look at all of the top running heads/cam vehicles, they will all have heads with excellent flow at .300,.400 and .500".
Tony Mamo from Airflow Research and I have discussed this theory at great length and we decided to build a set of heads that maximized the airflow at the low and mid-lifts, even if it meant limiting the airflow up high. This is challenging with a 3.900" bore as too large an intake valve will be shrouded by the chamber wall and cylinder bore. Based on the success he's had with opening up the chamber walls for 4.00" bore motors with the AFR 205s, Tony Mamo opened up the combustion chamber walls of my 205s from 3.900" to 4.000". This gave more space for the 2.02 valves to flow well in the low and mid lifts. But when you open up the chamber, you also lose compression. This means you have to mill more. To get to a 57cc chamber, we had to mill the new 205s close to .060". Most of the time, head flow numbers are posted in unmilled form, but when milled, they will often drop dramatically. Tony Mamo was very conscientious with his valve jobs to make sure the head flow in milled form was outstanding. Here is what my 205s flowed on a 3.900" bore at 28" of H2O:
AFR 205s with 57cc chamber:
Lift.........200", .300", .400", .500", .550", .600"
Intake.....158,.. 220,.. 264,.. 285,.. 296,.. 300
Exhaust.. 122,.. 178,.. 217,.. 232,.. N/A,.. 241 (with pipe)
While there's nothing special about the flow numbers at .600", look at the numbers down low. Most unmilled heads flow in the low 140s at .200", the high 190s or low 200s at .300", and high 240s at .400". Since we're trying to maximize airflow within the flow limits of the plastic intake manifold, a gain of 20 cfm at .300" and .400" will show huge hp gains (over 20 rwhp) whereas a flow gain of 20 cfm at .600" will show virtually no gain. Case in point: I used to have AFR 205s and I swapped to AFR small bore 225s. The 225s flowed 20 cfm better at .550", 22cfm better at .600", and 25 cfm better at .650" than my old 205s. Guess what? We gained virtually 0 hp with the swap.
We were even running a .650 lift cam to take advantage of the airflow. Nothing. The moral? Concentrate on getting more airflow within the flow limits of your intake manifold (ie, better flow at low and mid-lifts). Make sure your heads flow big numbers after they're milled.
On a side note, the 205s still retained the standard CNC porting from AFR. No additional material was removed. This meant that the airspeed was very high and throttle response is fantastic. My fuel economy has increased compared to running the AFR 225s.
Head flow
Compression
Camshaft selection
Exhaust selection
Intake manifold selection
Valvetrain geometry/stability
Finding lost hp mods
Head flow:
Contrary to popular belief, when running a plastic intake manifold on an LS1, airflow at .600" is virtually meaningless. There are several reasons why. First, an LS6 intake will start to lop off airflow above 265cfm. A stock FAST 90mm intake seems to lop it off around 275cfm and a ported FAST 90 seems to lop off flow above 280cfm. What all this means is that most all airflow gains above 280cfm will go un-noticed when you bolt a plastic intake up to it. The real trick is to pack in more airflow in the low and mid lifts. If you look at all of the top running heads/cam vehicles, they will all have heads with excellent flow at .300,.400 and .500".
Tony Mamo from Airflow Research and I have discussed this theory at great length and we decided to build a set of heads that maximized the airflow at the low and mid-lifts, even if it meant limiting the airflow up high. This is challenging with a 3.900" bore as too large an intake valve will be shrouded by the chamber wall and cylinder bore. Based on the success he's had with opening up the chamber walls for 4.00" bore motors with the AFR 205s, Tony Mamo opened up the combustion chamber walls of my 205s from 3.900" to 4.000". This gave more space for the 2.02 valves to flow well in the low and mid lifts. But when you open up the chamber, you also lose compression. This means you have to mill more. To get to a 57cc chamber, we had to mill the new 205s close to .060". Most of the time, head flow numbers are posted in unmilled form, but when milled, they will often drop dramatically. Tony Mamo was very conscientious with his valve jobs to make sure the head flow in milled form was outstanding. Here is what my 205s flowed on a 3.900" bore at 28" of H2O:
AFR 205s with 57cc chamber:
Lift.........200", .300", .400", .500", .550", .600"
Intake.....158,.. 220,.. 264,.. 285,.. 296,.. 300
Exhaust.. 122,.. 178,.. 217,.. 232,.. N/A,.. 241 (with pipe)
While there's nothing special about the flow numbers at .600", look at the numbers down low. Most unmilled heads flow in the low 140s at .200", the high 190s or low 200s at .300", and high 240s at .400". Since we're trying to maximize airflow within the flow limits of the plastic intake manifold, a gain of 20 cfm at .300" and .400" will show huge hp gains (over 20 rwhp) whereas a flow gain of 20 cfm at .600" will show virtually no gain. Case in point: I used to have AFR 205s and I swapped to AFR small bore 225s. The 225s flowed 20 cfm better at .550", 22cfm better at .600", and 25 cfm better at .650" than my old 205s. Guess what? We gained virtually 0 hp with the swap.
We were even running a .650 lift cam to take advantage of the airflow. Nothing. The moral? Concentrate on getting more airflow within the flow limits of your intake manifold (ie, better flow at low and mid-lifts). Make sure your heads flow big numbers after they're milled.On a side note, the 205s still retained the standard CNC porting from AFR. No additional material was removed. This meant that the airspeed was very high and throttle response is fantastic. My fuel economy has increased compared to running the AFR 225s.
08-17-2007, 02:17 AM
#6
TECH Senior Member
It is not a matter of flow only, the 1.8 will not handle the XE-R ramp shape and rate. Especialy with YTs which are heavy over the nose. over 6100 rpm will see unwanted float and harmonics.
08-17-2007, 10:46 AM
#7
Steve...
No go on the 1.8's
Predator pretty much nailed it. The lobe intensity at the valve increases to the point valve control issues are now a concern, which would completely negate any gains the slightly faster valve action may have brought to the table. Probably lose power at the higher RPM's. With very lightweight valves (titanium) you could probably pull it off but at that point its much cheaper just to install a slightly larger cam. Lift plays a much smaller role in power output when compared to duration. Try swapping to a 228/230 and see how that works for you. Shouldn't have a big negative effect on the bottom of the curve (a slight loss) but run a little harder in the midrange and higher RPM's.
Bottom line, an XER has a fast ramp design and is intended for use with 1.7 rocker ratios.
How's the ported intake working out for you?
Hope things are going well
Regards,
Tony
No go on the 1.8's
Predator pretty much nailed it. The lobe intensity at the valve increases to the point valve control issues are now a concern, which would completely negate any gains the slightly faster valve action may have brought to the table. Probably lose power at the higher RPM's. With very lightweight valves (titanium) you could probably pull it off but at that point its much cheaper just to install a slightly larger cam. Lift plays a much smaller role in power output when compared to duration. Try swapping to a 228/230 and see how that works for you. Shouldn't have a big negative effect on the bottom of the curve (a slight loss) but run a little harder in the midrange and higher RPM's.
Bottom line, an XER has a fast ramp design and is intended for use with 1.7 rocker ratios.
How's the ported intake working out for you?
Hope things are going well
Regards,
Tony
Last edited by Tony Mamo @ AFR; 08-17-2007 at 10:52 AM.
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08-19-2007, 03:36 AM
#8
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Thanks for the advice. How can i identify valve float from logging rather than on a dyno. It seems to be sustaining good airflow at high rpms but its often showing permanent maximum knock at above 6700rpm. Im running Dart 225 Heads with PSI springs and YT Ultralight 1.7s and Morel lifters.
The car recently went 118.9mph at 3700lb race weight with driver in 80deg F temps.
It has a 4200 stall and 4.11s
The Ported Fast is working well Tony. Thanks again.
The car recently went 118.9mph at 3700lb race weight with driver in 80deg F temps.
It has a 4200 stall and 4.11s
The Ported Fast is working well Tony. Thanks again.
08-20-2007, 02:34 AM
#9
Originally Posted by oztrack
Thanks for the advice. How can i identify valve float from logging rather than on a dyno. It seems to be sustaining good airflow at high rpms but its often showing permanent maximum knock at above 6700rpm. Im running Dart 225 Heads with PSI springs and YT Ultralight 1.7s and Morel lifters.
The car recently went 118.9mph at 3700lb race weight with driver in 80deg F temps.
It has a 4200 stall and 4.11s
The Ported Fast is working well Tony. Thanks again.
The car recently went 118.9mph at 3700lb race weight with driver in 80deg F temps.
It has a 4200 stall and 4.11s
The Ported Fast is working well Tony. Thanks again.
Good luck Steve. If you try the 1.8's let me know. I would bag the rockers and slide a larger stick in there. I will help you brew something up if you call me so we can exchange some info quicker than a PM session.
Cheers,
Tony
