They don't work well with Gas EGT's (Used on diesels)
Anarky(Derek) on SF was playing around with them an I followed his thread there!
Anarky(Derek) on SF was playing around with them an I followed his thread there!
cylinder head porting theories... and such
- Thread starter flubyux2
- Start date
IJ. said:
If you dont mind my lack of searching on that damned website....how did it turn out?
-Jonathan
LOL dunno they changed the access for non members and that was the end of me browsing there 
I think it was in Mk4 Tech.
I think it was in Mk4 Tech.
siman said:
I had always wondered about making a turbo charger like that. But I never knew they exsisted.
Good Stuff :bigthumb:
Defiant 7M
I did not retain the name of the shop. I am glad you posted it. I used the word hogged out not to insult his work but to exagerate what most people think port jobs are. Just go in there and remove as much material as possible. Some areas dont need to be touched much and removing to much may make the port flow less.
Those new numbers are outstanding. I did unshroud the valves but not much since i did not have access to or the money to do the proper testing involved to remove the appropriate material in the ports to push it further.
To increase the flow as i did i think most people can do it themselves especially the ridges under the valve seats. A little work will open up the ports greatly. Just be sure to get the head flow tested to make sure each port flows similar numbers. To increase the flow further would require the attention to detail that was applied to your head and would cost good money.
I did not retain the name of the shop. I am glad you posted it. I used the word hogged out not to insult his work but to exagerate what most people think port jobs are. Just go in there and remove as much material as possible. Some areas dont need to be touched much and removing to much may make the port flow less.
Those new numbers are outstanding. I did unshroud the valves but not much since i did not have access to or the money to do the proper testing involved to remove the appropriate material in the ports to push it further.
To increase the flow as i did i think most people can do it themselves especially the ridges under the valve seats. A little work will open up the ports greatly. Just be sure to get the head flow tested to make sure each port flows similar numbers. To increase the flow further would require the attention to detail that was applied to your head and would cost good money.
flubyux2,
your trying to make the mythical 100% efficiant machine. you said so in your post that you have to overcome frition losses in the turbo but i dont think you gave friction enough credit. uf you were running 15psi the exaust pressure would be way higher than 15psi. and it goes the other way, is exaust pressure was 15psi the intake pressure would be alot lower. in the august 2004 edition of Sport Compact Car they were testing their srt-4, they claim in the artical that backpressure in the exaust manifold can be as high as 35psi, unfortunatly i dont know how much boost they were running. bottom line: you cant get more than you put in, cant get as much as you put in, cant even come close.
fasinating chat we're having here
your trying to make the mythical 100% efficiant machine. you said so in your post that you have to overcome frition losses in the turbo but i dont think you gave friction enough credit. uf you were running 15psi the exaust pressure would be way higher than 15psi. and it goes the other way, is exaust pressure was 15psi the intake pressure would be alot lower. in the august 2004 edition of Sport Compact Car they were testing their srt-4, they claim in the artical that backpressure in the exaust manifold can be as high as 35psi, unfortunatly i dont know how much boost they were running. bottom line: you cant get more than you put in, cant get as much as you put in, cant even come close.
fasinating chat we're having here
Halsupramk3 said:
Hey man it's all good :bigthumb: You bring some awesome info to the table...Thanks
yeah. well, a well balanced motor would have pressures in the intake manifold that is somewhere near the pressure seen in the exhaust manifold. just because SCC did a test on the SRT4 and saw 35psi of back pressure in that manifold doesnt mean that is the norm. what you are talking about sounds like its a stock setup, which means its a Small exhaust side for the quick spool. quick spooling means that its a small AR and less air flow than a larger AR. jsut upsizing toa larger exhaust housing would yeild more top end power.
and yes, aparently equalizing air in and air out would mean 100% VE. when you improve this, you improve torque. if you can improve the VE of your motor, its evident in NA and FI form; regardless of aspiration, itll benefit.
i would be pleased if i could get my ports to flow 200cfm, let alone 240cfm!!! thats insane. if i can get 200cfm at 0.300" lift, ill be a happy camper.
I do know that the rapid expansion of exhaust gasses does cause the pressure inside the exhaust manifold to increase moreso over the pressure that was inside the cylinder while under boost .
id like to look into using the stock 2J valves, and going 1.5mm OS. but, i think taht would require the used of New valve seats as well. i have a feeling that i wouldnt be able to reuse the stock valve seats. im not sure if i should port the valve bowls before or after the new seats... iid hate to nick one of the seats whilst grinding out.
and yes, aparently equalizing air in and air out would mean 100% VE. when you improve this, you improve torque. if you can improve the VE of your motor, its evident in NA and FI form; regardless of aspiration, itll benefit.
i would be pleased if i could get my ports to flow 200cfm, let alone 240cfm!!! thats insane. if i can get 200cfm at 0.300" lift, ill be a happy camper.
I do know that the rapid expansion of exhaust gasses does cause the pressure inside the exhaust manifold to increase moreso over the pressure that was inside the cylinder while under boost .
id like to look into using the stock 2J valves, and going 1.5mm OS. but, i think taht would require the used of New valve seats as well. i have a feeling that i wouldnt be able to reuse the stock valve seats. im not sure if i should port the valve bowls before or after the new seats... iid hate to nick one of the seats whilst grinding out.
Hey Fluby, you're going with a tubular manifold, so look into it.
My Trust mani has ports nearly identical to the gasket size.
Normaly this would mean you would need to retain the anti reversion dam in the head to maintain exhaust direction, inirtia, and velocity.
However, my mani has runners nearly .25" larger than the ports, so I have a new anti reversion dam built into the manifold.
Consequently, you should be able to maintain low lift numbers with the manifold in place. Does anyone flow test the heads with the exhaust manifold in place? I'm assuming that the manifold cannot increase volume, but it should be able to create the venturi effect and increase low lift velocity in a head that is gasket matched.
Just my meager thoughts...
-Jake
My Trust mani has ports nearly identical to the gasket size.
Normaly this would mean you would need to retain the anti reversion dam in the head to maintain exhaust direction, inirtia, and velocity.
However, my mani has runners nearly .25" larger than the ports, so I have a new anti reversion dam built into the manifold.
Consequently, you should be able to maintain low lift numbers with the manifold in place. Does anyone flow test the heads with the exhaust manifold in place? I'm assuming that the manifold cannot increase volume, but it should be able to create the venturi effect and increase low lift velocity in a head that is gasket matched.
Just my meager thoughts...
-Jake
Just a question:
If you put in 1.5mm larger valves and do not put in larger valve seats wouldn't that create a restriction that would damper the effect you are wanting to create with the larger valve.
What good is a larger valve if it is not opening up a larger seat and larger port?
In the intake you want the exit of the port, the bowl area at the seat to be the smallest diameter of the whole port. If the exit is the smallest part of the port it will help to keep velocity up. Also, another question. If the valve is larger and the seat is the same diameter is that not just a larger piece of metal for the air to flow around? Just a larger obstruction?
Am i missing some information about the benefits of just a larger valve?
If you put in 1.5mm larger valves and do not put in larger valve seats wouldn't that create a restriction that would damper the effect you are wanting to create with the larger valve.
What good is a larger valve if it is not opening up a larger seat and larger port?
In the intake you want the exit of the port, the bowl area at the seat to be the smallest diameter of the whole port. If the exit is the smallest part of the port it will help to keep velocity up. Also, another question. If the valve is larger and the seat is the same diameter is that not just a larger piece of metal for the air to flow around? Just a larger obstruction?
Am i missing some information about the benefits of just a larger valve?
hey hal, typically, the valve seats are actually milled out to fit the valves, then ground w/ stones on 3 angles. sometimes, the valve seats are cut w/ a milling bit which already has the 3 or 5 angles on it for the new diameter. so the valve seat is automatically enlarged for the proper size valve.
1mm oversize is about the safe limit of the stock valve seats. going to a 1.5mm OS valve diameter is pushing the physical size limits of the stock seats . at this pont, they should be cut out, resize the head and install new valve seats of a larger diameter to accomodate the "significantly" larger valves.
1J, i will be going with a custom Tubular manifold. ill be using the 1.75" low carbone steel weld els which have a 1.6" ID IIRC. itll be slightly larger than the stock exhaust ports. i dont want to hog out the exhaust ports either. im just going to smooth them and massage them further down behind the valves, near the divider and the valve stems.
i want to figure out a way to mount the T88 close to the front of the motor, where the PS resivoir normally sits, so i have room for a 4" DP and a long sweeping radius DP.
should i go w/ the 2.0" weld els which have a 1.8" ID or stick w/ the smaller size? im thinkng a 2.0" may be better for a mid and top end power band.
1mm oversize is about the safe limit of the stock valve seats. going to a 1.5mm OS valve diameter is pushing the physical size limits of the stock seats . at this pont, they should be cut out, resize the head and install new valve seats of a larger diameter to accomodate the "significantly" larger valves.
1J, i will be going with a custom Tubular manifold. ill be using the 1.75" low carbone steel weld els which have a 1.6" ID IIRC. itll be slightly larger than the stock exhaust ports. i dont want to hog out the exhaust ports either. im just going to smooth them and massage them further down behind the valves, near the divider and the valve stems.
i want to figure out a way to mount the T88 close to the front of the motor, where the PS resivoir normally sits, so i have room for a 4" DP and a long sweeping radius DP.
should i go w/ the 2.0" weld els which have a 1.8" ID or stick w/ the smaller size? im thinkng a 2.0" may be better for a mid and top end power band.
Flub: Guess it all comes down to the total package and where you want it to make power!
Are you going for a short runner intake?
Are you going for a short runner intake?
1J, im going for maybe a 7500rpm rev limit, that the most. i want a 3.3L. if i cant get it going all bore, ill have to stroke some and may just rev to 7000 for saftey's sake.
ill probably keep stock length runners and larger intake plenum. ill probably use the manifold i have now if no one buys it. its like a 3.8L capacity "Surge tank" on the stock upper runners.
its still going to be a daily driver, i dont want to lose all bottom end on it by just using the lower runners, joo know?
ill probably keep stock length runners and larger intake plenum. ill probably use the manifold i have now if no one buys it. its like a 3.8L capacity "Surge tank" on the stock upper runners.
its still going to be a daily driver, i dont want to lose all bottom end on it by just using the lower runners, joo know?
siman said:
i know that alot of the turbo ford guys use turbo chargers from diesels and i think one guy said he got the control for it to work. he said it screamed like a small turbo and then opened up the only problem he had was keeping the boost from creeping.
Flub: This is going to be a really interesting build up!
(pretty well the opposite in theory to my build up)
I think headwork and cams are going to be a critical choice in this motor to achieve your goals!
I hope you document it all and run a build log!
I noticed in the "Cams make a difference on the dyno" thread that on the stock cams the power was levelling out at 5kish which backs up the thoughts/feelings most guys have that the 7M stops making power around there so there's no reason to rev em!
The second curve with the cams really made a difference up above 5k and is an eye opener!
(pretty well the opposite in theory to my build up)
I think headwork and cams are going to be a critical choice in this motor to achieve your goals!
I hope you document it all and run a build log!
I noticed in the "Cams make a difference on the dyno" thread that on the stock cams the power was levelling out at 5kish which backs up the thoughts/feelings most guys have that the 7M stops making power around there so there's no reason to rev em!
The second curve with the cams really made a difference up above 5k and is an eye opener!
i may just try to run some mixed HKS cams, like 264 and 272 and not try to rev to high. i dont want the power to peak too far up there, obviously. but the longer i can stay in gear, the faster i will be.
i still have to sell my red supra and put my black supra together as my DD. then i have to order a Soarer as my platform. and at that point, ill slowly build up the motor. i get easily distracted w/ projects like i want to try to go for stock CT26 record on my DD, for poop and laughs. then, i have an RX7 that i want to do an S5 T2 swap into. then, i want to build a 99 Impreza L coupe w/ a 2.2L and FP green and set it up for rally.
anyways, if you look at the intake ports, there is a slight bevel around the inlet where it starts at the intake manifold flange.the actual port has about a 2mm reduction in size when transitioning from the intake manifold to the intake port. i basically want to port out the intake runner 2mm all the way around to match the intake manifold runner size (PS, thats been ported and slightly polished too, as well as the runners on the upper intake). then, id like to port out the same amount on the exhaust side, about 2mm all the way around, or enlarge by 4mm total. im thinking that the valve bowls, valve guide bosses and port dividers are going to be the areas that need the most attention. i want to reduce the valve guides so they take up less area, but i dont want to cut them back to the roof of the port. my valve guide life expectancy will reduce greatly if i cut the guide back that far.
i need to find a vaccuum cleaner with a known airflow rate, then i can take the vaccuum reading for the assumed flow rate. then affix it to my intake port whilst im porting so i can watch the fluctuations in vaccum readings as i remove material. itll be better than nothing and ill have some idea of how much to port on each runner to try and achieve equal readings so i can have some sort of semblance of a balanced airflow across all cylinders. i would actually be content w/ 200cfm per port. 220cfm @ no more than 0.350" lift would make my day though.
i still have to sell my red supra and put my black supra together as my DD. then i have to order a Soarer as my platform. and at that point, ill slowly build up the motor. i get easily distracted w/ projects
like i want to try to go for stock CT26 record on my DD, for poop and laughs. then, i have an RX7 that i want to do an S5 T2 swap into. then, i want to build a 99 Impreza L coupe w/ a 2.2L and FP green and set it up for rally. anyways, if you look at the intake ports, there is a slight bevel around the inlet where it starts at the intake manifold flange.the actual port has about a 2mm reduction in size when transitioning from the intake manifold to the intake port. i basically want to port out the intake runner 2mm all the way around to match the intake manifold runner size (PS, thats been ported and slightly polished too, as well as the runners on the upper intake). then, id like to port out the same amount on the exhaust side, about 2mm all the way around, or enlarge by 4mm total. im thinking that the valve bowls, valve guide bosses and port dividers are going to be the areas that need the most attention. i want to reduce the valve guides so they take up less area, but i dont want to cut them back to the roof of the port. my valve guide life expectancy will reduce greatly if i cut the guide back that far.
i need to find a vaccuum cleaner with a known airflow rate, then i can take the vaccuum reading for the assumed flow rate. then affix it to my intake port whilst im porting so i can watch the fluctuations in vaccum readings as i remove material. itll be better than nothing and ill have some idea of how much to port on each runner to try and achieve equal readings so i can have some sort of semblance of a balanced airflow across all cylinders. i would actually be content w/ 200cfm per port. 220cfm @ no more than 0.350" lift would make my day though.
Flub: LOL about number of projects! (this gets me all the time I think I have add or something)
Good to see you're going to build your own flow bench for the porting, it doesn't matter if it's a $40K sophisticated one or a home built as long as you can get comparative readings!
Back in the day I did a bit of flow testing and was surprised at the results as a lot of the time conventional wisdom didn't give the expected results! (the old school way was hog out as much as possible)
Good to see you're going to build your own flow bench for the porting, it doesn't matter if it's a $40K sophisticated one or a home built as long as you can get comparative readings!
Back in the day I did a bit of flow testing and was surprised at the results as a lot of the time conventional wisdom didn't give the expected results! (the old school way was hog out as much as possible)
Have any of you guys read the new SCC ( sport compact car) tech section? About the Cosworth ( ford) Cart motor?
I looked at the intake ports, they are NOT smooth, rather, the whold head is CNC machined and there are gallies leading into the combustion chamber ( valve area "pent roof" design)....i guess it keeps the air from knocking against the sides of the port walls?
Let me see if i can find some pics:
http://www.sportcompactcarweb.com/toc/thismonth/index.html
well there is the issue....go pick it up on newstands now, just for that article!
I was amazed at the simplicity that those engines are developed with! no counterweights on the crank, and the ( out of eight) 2 rods share one bearing on the crank!!!!! weird!
anyways....lol
-Jonthan
I looked at the intake ports, they are NOT smooth, rather, the whold head is CNC machined and there are gallies leading into the combustion chamber ( valve area "pent roof" design)....i guess it keeps the air from knocking against the sides of the port walls?
Let me see if i can find some pics:
http://www.sportcompactcarweb.com/toc/thismonth/index.html
well there is the issue....go pick it up on newstands now, just for that article!
I was amazed at the simplicity that those engines are developed with! no counterweights on the crank, and the ( out of eight) 2 rods share one bearing on the crank!!!!! weird!
anyways....lol
-Jonthan
so, yeah, after the fuel is introduced into the intake path, you need to have a rough surface so that it creates enough turbulence so that the fuel does not regroup and fall out of the airstream. when you port the head, you want to go no smoother than a 40grit sanding roll. or a sand cast finish. but before that, you can polish it to a mirror shine, same with the exhaust side.
i didnt see the pics of the cosworth stuffs... i wanna check out those galleies that you speak of. i know that some head porters grind a shallow channel or dip into the valve bowl leading into the valve opening. this creates a swirl effect so that the cylinders fill up like a coiled rope... there are 2 different head designs; tumble port and swirl port. our heads and jz heads are tumble port. it keeps the fuel and air mixed and burns efficiently and reduces hydrocarbon emissions. due to the irregular cylinder filling, tumble port desing doesnt promote maximum fillery. however, swirl port is different. it fills the cylinders more compactly.
think of it like soft serve ice cream. just filling the cup or cone with ice cream falling as it may will create gaps where it wont fill efficiently and completely. however, when you swirl the cup/cone, the ice cream lays down in coils and will fill more completely.
i didnt see the pics of the cosworth stuffs... i wanna check out those galleies that you speak of. i know that some head porters grind a shallow channel or dip into the valve bowl leading into the valve opening. this creates a swirl effect so that the cylinders fill up like a coiled rope... there are 2 different head designs; tumble port and swirl port. our heads and jz heads are tumble port. it keeps the fuel and air mixed and burns efficiently and reduces hydrocarbon emissions. due to the irregular cylinder filling, tumble port desing doesnt promote maximum fillery. however, swirl port is different. it fills the cylinders more compactly.
think of it like soft serve ice cream. just filling the cup or cone with ice cream falling as it may will create gaps where it wont fill efficiently and completely. however, when you swirl the cup/cone, the ice cream lays down in coils and will fill more completely.