Cylinder heads, short blocks, flow benches....
In Timeout
Joined: Dec 2003
Posts: 349
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From: Kennesaw Ga
I do know what the head is, just wondering what the Benefits are to doing that work Higher rev?
Originally posted by webguy330i
Not to bash you, but how do you drive a 417hp evo and not know what a head is?
Not to bash you, but how do you drive a 417hp evo and not know what a head is?
Better air/fuel mixing and flow, better exhaust flow, better combustion/swirl, better... well the list goes on. And yes higher revs if you upgrade the valvetrain appropriately.
Wow, alot of questions.
Stock springs are pretty poor, the stock retainers are awesome as far as weight goes. Half of what a Crower titanium weighs. Problem is it is very small since the EVO uses a tapered spring, it can't be used in anything else.
I haven't looked to see what the stock EVO cam has for lift. The highest lift in the HKS cams for the 4g63 are about .415.
The stock springs have plenty of room so that they don't coil bind, highest of any stock Mitsu spring we have tested. The spring rate is just low and I would be afraid to run them at very high RPM's.
Yes you will see considerable gains even with stock cams and the port work. We work on the flow under say .500 lift, this is all that you will ever see so there is no sense in working it higher, besides working it higher than .500 kills the low lift flow numbers.
We have measured the spring rates in the stock springs in the EVO, all the DSM's springs of the past and every aftermarket spring that we know of that is available for the 4g63.
The head for the EVO ported, o-ringed, new springs, retainers (titanium) and valves will run $1600. It will require a core.
The valve sizes that we will use will remain a mystery. I have to get the head on the bench stock and ported. Then we will experiment with different size valves to see what flows the best. The biggest valve in the past has been the worst flowing on the bench.
I was under the impression in the past that the larger you made everything on a turbo head the better. Same thought as you had. I figured what the hell, it is under 30+ PSI of boost. Well after talking with people that actually know something I was told this way of thinking was dumb. Then it was proven to me on the flow bench and then the dyno. All of the "hard" work I was putting into the heads I was doing was a waste of time. I was doing it all wrong. Now the heads are ported so they flow and when they are bolted on they make big power gains and make it all the way across the RPM's. To answer your question, the heads need to be ported like you would a naturally aspirated head.
Stock rods. Yes, they have made some big power, how long before they grenade? Many of us will find out. I have used Crower, Groden and Eagle rods in my engines. The aluminum rods I wouldn't recommend, pain to clearance the blocks, not for street use and I didn't gain jack **** from running them. The Crowers are the best rod going........but the Eagles have proven to be a great rod at low cost that has refused to fail. The machine work on the Eagle is also the best I have found. I have yet to re-size a new Eagle rod, the same can't be said for some of the Crowers I have pulled out of the box. I have gone 7.8 at 175 mph on the Eagle rod, I haven't seen a failure yet. That is over 770 whp through a very ineffient 8" torque converter. I would guess the flywheel hp to be in the area of 950-1,000 hp. This is also running the engine to 10,000 rpm. I am trying to say it is a good rod. This is also the same head we sell to the public, nothing different at all.
Hope this helps,
David Buschur
www.buschurracing.com
Stock springs are pretty poor, the stock retainers are awesome as far as weight goes. Half of what a Crower titanium weighs. Problem is it is very small since the EVO uses a tapered spring, it can't be used in anything else.
I haven't looked to see what the stock EVO cam has for lift. The highest lift in the HKS cams for the 4g63 are about .415.
The stock springs have plenty of room so that they don't coil bind, highest of any stock Mitsu spring we have tested. The spring rate is just low and I would be afraid to run them at very high RPM's.
Yes you will see considerable gains even with stock cams and the port work. We work on the flow under say .500 lift, this is all that you will ever see so there is no sense in working it higher, besides working it higher than .500 kills the low lift flow numbers.
We have measured the spring rates in the stock springs in the EVO, all the DSM's springs of the past and every aftermarket spring that we know of that is available for the 4g63.
The head for the EVO ported, o-ringed, new springs, retainers (titanium) and valves will run $1600. It will require a core.
The valve sizes that we will use will remain a mystery. I have to get the head on the bench stock and ported. Then we will experiment with different size valves to see what flows the best. The biggest valve in the past has been the worst flowing on the bench.
I was under the impression in the past that the larger you made everything on a turbo head the better. Same thought as you had. I figured what the hell, it is under 30+ PSI of boost. Well after talking with people that actually know something I was told this way of thinking was dumb. Then it was proven to me on the flow bench and then the dyno. All of the "hard" work I was putting into the heads I was doing was a waste of time. I was doing it all wrong. Now the heads are ported so they flow and when they are bolted on they make big power gains and make it all the way across the RPM's. To answer your question, the heads need to be ported like you would a naturally aspirated head.
Stock rods. Yes, they have made some big power, how long before they grenade? Many of us will find out. I have used Crower, Groden and Eagle rods in my engines. The aluminum rods I wouldn't recommend, pain to clearance the blocks, not for street use and I didn't gain jack **** from running them. The Crowers are the best rod going........but the Eagles have proven to be a great rod at low cost that has refused to fail. The machine work on the Eagle is also the best I have found. I have yet to re-size a new Eagle rod, the same can't be said for some of the Crowers I have pulled out of the box. I have gone 7.8 at 175 mph on the Eagle rod, I haven't seen a failure yet. That is over 770 whp through a very ineffient 8" torque converter. I would guess the flywheel hp to be in the area of 950-1,000 hp. This is also running the engine to 10,000 rpm. I am trying to say it is a good rod. This is also the same head we sell to the public, nothing different at all.
Hope this helps,
David Buschur
www.buschurracing.com
Hey,
I was reading Hot Rod magazine last night and there is a really good article in there from Air Flow Research. The article is on a new LS1 head they developed. Just so you guys can verify what I am telling you go pick up the magazine and read it. You'll see numbers and charts from different heads for the LS1 and you'll see that they too have focused on flow across the board rather than a big *** peak number. Interesting reading and funny how closely it matches what I have typed here.
David Buschur
www.buschurracing.com
I was reading Hot Rod magazine last night and there is a really good article in there from Air Flow Research. The article is on a new LS1 head they developed. Just so you guys can verify what I am telling you go pick up the magazine and read it. You'll see numbers and charts from different heads for the LS1 and you'll see that they too have focused on flow across the board rather than a big *** peak number. Interesting reading and funny how closely it matches what I have typed here.
David Buschur
www.buschurracing.com
Wow, been a busy couple of weeks for the flow bench. Finally have some hard numbers.
I am at home and I can't sleep as usual. It is 2 am. I wish I had brought the flow sheets home with me.
What I can tell you is we have finished the flow bench testing on the 1g head and the EVO head on the same day so we have numbers to compare. We are use to making power with the 1g 4g63 head and wanted a new fresh baseline from the same day.
I need my damn charts!!! I guess this is going to just be a teaser for you guys until I can quote some of the gains and comparisons.
A few things I am going to say. I AM NOT GOING TO POST ANY CFM NUMBERS AT ALL!! They are going to do NO good. I just compared the 1g head numbers to another companies on the same brand flow bench we use, no comparison. I mean it isn't even close. As an example. Same flow benches, two different parts of the country, same basic head. At .100 inches of lift on the other companies bench the head flowed 64 cfm, on our bench it flowed 110 cfm. That isn't even freaking close. So as I said, flow benches are like dynos, everyone is different and comparing numbers from one to another is a waste of time.
I will say the one thing I can remember from the sheets are the EVO exhaust port completely stalls in flow. At .300, .400 and .500 lift the head flowed the exact same number. After I ported it it picked up 19%, 23% and 21% more flow at those same lift numbers over stock. I have NEVER had this much increase in porting a DSM head. I completely amazed myself. The intake side did not pick up nearly as much, as a matter of fact the gains on the intake were small. I will have to look to see exactly.
I am very excited about what I have found so far. The exhaust side of the head was the weakest and is the most important, it is now greatly improved.
I will try and get some comparisons up right away.
We will be ready to do the EVO heads within days. Next we are going to do more tests on some different valves and valve sizes. The numbers so far are with the STOCK EVO valves in the head. In the past we have gained from our valves, have to see on this particular head. I am also very curious to see what will be gained with the larger valves. It has been a big suprise in the past.
Right after the valve testing I will be doing a little more port work on the head to see what can be done to further improve it.
I would say anyone needing a head done could send it in now, by the time it is hottanked and checked we will be ready to start porting them.
Stay tuned...........
David Buschur
www.buschurracing.com
I am at home and I can't sleep as usual. It is 2 am. I wish I had brought the flow sheets home with me.
What I can tell you is we have finished the flow bench testing on the 1g head and the EVO head on the same day so we have numbers to compare. We are use to making power with the 1g 4g63 head and wanted a new fresh baseline from the same day.
I need my damn charts!!! I guess this is going to just be a teaser for you guys until I can quote some of the gains and comparisons.
A few things I am going to say. I AM NOT GOING TO POST ANY CFM NUMBERS AT ALL!! They are going to do NO good. I just compared the 1g head numbers to another companies on the same brand flow bench we use, no comparison. I mean it isn't even close. As an example. Same flow benches, two different parts of the country, same basic head. At .100 inches of lift on the other companies bench the head flowed 64 cfm, on our bench it flowed 110 cfm. That isn't even freaking close. So as I said, flow benches are like dynos, everyone is different and comparing numbers from one to another is a waste of time.
I will say the one thing I can remember from the sheets are the EVO exhaust port completely stalls in flow. At .300, .400 and .500 lift the head flowed the exact same number. After I ported it it picked up 19%, 23% and 21% more flow at those same lift numbers over stock. I have NEVER had this much increase in porting a DSM head. I completely amazed myself. The intake side did not pick up nearly as much, as a matter of fact the gains on the intake were small. I will have to look to see exactly.
I am very excited about what I have found so far. The exhaust side of the head was the weakest and is the most important, it is now greatly improved.
I will try and get some comparisons up right away.
We will be ready to do the EVO heads within days. Next we are going to do more tests on some different valves and valve sizes. The numbers so far are with the STOCK EVO valves in the head. In the past we have gained from our valves, have to see on this particular head. I am also very curious to see what will be gained with the larger valves. It has been a big suprise in the past.
Right after the valve testing I will be doing a little more port work on the head to see what can be done to further improve it.
I would say anyone needing a head done could send it in now, by the time it is hottanked and checked we will be ready to start porting them.
Stay tuned...........
David Buschur
www.buschurracing.com
Yes, sooner or later we will have spare cores around. In the meantime we can turn a head around in 2 weeks time now. I bought a brand new head from the dealer to start the port work on.
No target RPM in particular. By increasing the flow across the board on the cylinder head we should see an increase EVERYWHERE, not just an increase in peak power.
The cylinder head is probably going to be the next thing we test on the car. As soon as the next round of flow benching is done I will match the other ports up to the best one we come up with. More than likely we will go ahead and bolt it on the car then.
David Buschur
www.buschurracing.com
No target RPM in particular. By increasing the flow across the board on the cylinder head we should see an increase EVERYWHERE, not just an increase in peak power.
The cylinder head is probably going to be the next thing we test on the car. As soon as the next round of flow benching is done I will match the other ports up to the best one we come up with. More than likely we will go ahead and bolt it on the car then.
David Buschur
www.buschurracing.com
David,
Are you saying the best rods for an EVO will be from Eagle(Talon?)? I would ask you about titanum rods but you'll probably say they'll be too expensive and they are overrated.
You are making me proud of myself in choosing the EVO (4G63) over you know what. Your research and testing will be helping the EVO community spank every car out on the street and dragstrip.
I know it wont be long until you experiment with the evo transmission set-up as well.
If you run for president, you got my vote!
STi
Are you saying the best rods for an EVO will be from Eagle(Talon?)? I would ask you about titanum rods but you'll probably say they'll be too expensive and they are overrated.
You are making me proud of myself in choosing the EVO (4G63) over you know what. Your research and testing will be helping the EVO community spank every car out on the street and dragstrip.
I know it wont be long until you experiment with the evo transmission set-up as well.
If you run for president, you got my vote!
STi
Last edited by BadBoyBeltran; Feb 1, 2004 at 03:10 PM.
Any idea on pricing to just do a bit of port work? I already have different retainers and springs, and since I am going to stick with pump gas I do not think that I will gain much by going with larger valves (not to mention we do not even know if larger valves will help our head anyway), so basically I am just looking to port. Just wanted to know how much. I would think that cleaning up the exhaust side would really help the spool-up times, especially with a different turbo. 
Do you want us to assemble the head? O-ring the head? Mill the head? The heads are going to be $1600 with all the best stuff we have. This will include the springs, retainers and more than likely the valves. I don't see the valves NOT picking up the head.
I will know this afternoon.
I really don't like breaking the head work up, I will but don't like to do it.
Why not send me a PM and let me know more of what you want to do.
David Buschur
I will know this afternoon.
I really don't like breaking the head work up, I will but don't like to do it.
Why not send me a PM and let me know more of what you want to do.
David Buschur
Here is some quick information on the head testing. The head so far has had port work done retaining the stock valves. The head is going back on the bench today to see how much the larger valve picks the head up.
To date this is what we have gotten:
Intake
Lift % of increase over stock
.100 4%
.200 1%
.300 4%
.400 9%
.500 8%
These gains aren't huge needless to say, decent for what has been done. The cams doesn't go to .500 lift but is in the .420 lift range so we flow at .500 too.
Exhaust
Lift % increase over stock
.100 -2%
.200 7%
.300 19%
.400 23%
.500 21%
Now these are some great gains! The exhaust side gains are huge and should make a big difference when this hits the dyno.
I am not listing the CFM of the head stock or ported. The flow bench, like the dyno is a tool. It will do nothing but cause huge pissing matches just like dyno conversations do here.
The gain is what is important and that is all I want to discuss.
Off to the porting bench.
David Buschur
www.buschurracing.com
To date this is what we have gotten:
Intake
Lift % of increase over stock
.100 4%
.200 1%
.300 4%
.400 9%
.500 8%
These gains aren't huge needless to say, decent for what has been done. The cams doesn't go to .500 lift but is in the .420 lift range so we flow at .500 too.
Exhaust
Lift % increase over stock
.100 -2%
.200 7%
.300 19%
.400 23%
.500 21%
Now these are some great gains! The exhaust side gains are huge and should make a big difference when this hits the dyno.
I am not listing the CFM of the head stock or ported. The flow bench, like the dyno is a tool. It will do nothing but cause huge pissing matches just like dyno conversations do here.
The gain is what is important and that is all I want to discuss.
Off to the porting bench.
David Buschur
www.buschurracing.com
Originally posted by davidbuschur
Do you want us to assemble the head? O-ring the head? Mill the head? The heads are going to be $1600 with all the best stuff we have. This will include the springs, retainers and more than likely the valves. I don't see the valves NOT picking up the head.
I will know this afternoon.
I really don't like breaking the head work up, I will but don't like to do it.
Why not send me a PM and let me know more of what you want to do.
David Buschur
Do you want us to assemble the head? O-ring the head? Mill the head? The heads are going to be $1600 with all the best stuff we have. This will include the springs, retainers and more than likely the valves. I don't see the valves NOT picking up the head.
I will know this afternoon.
I really don't like breaking the head work up, I will but don't like to do it.
Why not send me a PM and let me know more of what you want to do.
David Buschur
Considering the fact that your testing shows the exhaust port doesn't flow very well, do you think this would be the major factor as to why the stock turbo can't push over ~20 psi?
I just find it strange that the 16G application for the DSM can push up to 25 psi w/out boost taper, but not on the Evo8.
