2g head on a 1g???

[dnhieu]

i got a built 2g head and im just curious on EVERYTHING needed to put it on. i know im going to need a 2g water pipe, thermostat housing, and thermostat. also should i run a 1g or 2g intake manifold?

thanks in advance.
david

 

[bling5tatus]

1g intake is bigger.

 

[dsm-onster]

Stick w/ the 2g intake manifold. Or, get the head port matched to a 1g intake. If you just drop on the 1g intake manifold then you'll have a huge "step" to destroy the airflow to your valves. Like bling5tatus said, the 1g intake runners are wider than the 2g head runners. Has there been port work done?

That's not to say that a built 2g head is inferior to a 1G head. After all, you DO now have enough "meat" to actually get good port work done. Looking at the 1g head intake runners, it seams that we actually need some welding up to get the runners to flow better. . .

 

[Meh987]

Also need to have the head bolt holes in the 2g head bored out 1mm to fit the bigger head bolts. Im not sure if this is completely neccessary, as my cousin forced his on. I had mine bored out at the machine shop.

 

[MyÜberFastGSX]

I did a 6 bolt swap, and built my 2g head. I'm also running a 2g intake manifold and a ported evo3 exhaust manifold. I'm about 400 awhp right now and running strong. Putting in my DSM Link, and my BC 272 cams, springs and retainers, and should be at around 450. I'm also having English racing prep my car for E98 which is 120 octane Ethynol at $3.50 a gallon. All said and done about 550 awhp next week.

Wish me luck .

 

[eclipsh]

DON'T port the head to use a 1g manifold or you'll ruin it. The 2g head and intake manifold has a much better flow rating than the 1g because of the angle the air comes at the valves. By porting the head out for a 1g mani you ruin that angle and make the head flow LESS instead of more.

Beyond that, I'd like to know as well. I'll likely be buying a 2g head for my 1g when I do a rebuild in the future.

 

[dsm-onster]

DON'T port the head to use a 1g manifold or you'll ruin it. The 2g head and intake manifold has a much better flow rating than the 1g because of the angle the air comes at the valves. By porting the head out for a 1g mani you ruin that angle and make the head flow LESS instead of more.

VERY interesting! Where did you get this info? This is good to know.

However, swapping a SMIM onto a 2g intake manifold will alter that angle, too.

 

[dnhieu]

well here is the deal. i have a ported 2g head with manley springs and retainers. right now i have forced performance pf2 cams. im thinking while i will be building the motor shortly that i will have the holes drilled out 1mm over and purchase a 2g SMIM. what do you guys think about that? i know a 2g head flows more air then a 1g head even tho a 1g head is bigger. mine is ported and i seriously want to see what this head will do but i want to mix and match the correct parts so im not fighting myself...

thanks again
david

 

[dsm-onster]

well here is the deal. i have a ported 2g head with manley springs and retainers. right now i have forced performance pf2 cams. im thinking while i will be building the motor shortly that i will have the holes drilled out 1mm over and purchase a 2g SMIM. what do you guys think about that? i know a 2g head flows more air then a 1g head even tho a 1g head is bigger. mine is ported and i seriously want to see what this head will do but i want to mix and match the correct parts so im not fighting myself...

thanks again
david

Looks like a good plan to me. You have more air coming up to the valve. Let them be wider. . . as long as it doesn't alter any shortside radius port work done. I don't know what kind of port job you have or exactly what the 2g needs in that area. Best to talk to your head guy you used.

 

[dnhieu]

i got the head from a good friend awhile back. he ran it for a little while and went bigger and badder with his 2.3 stroker. i had the head decked and cleaned, bronze valve guides pressed in, 3 angle valve job, and new valve stem seals. i installed the used stock valves (appeared to be good) and manley springs and retainers myself. i kinda just want to assemble everything im going to need to get the job done all at one time...

 

[eclipsh]

Here is one thread where I read about it. I also read an article about it in Sport Compact or some other rag a year or so ago.

 

[dsm-onster]

Oh! I've read that thread. SEVERAL times.

All that shows --or speculates-- is that a 2g head w/ the proper port work has the potential to outflow a 1g head. There is nothing in there about a 2g head and intake manifold being proven to flow more than a 1g head and intake manifold. Again, 2g guys gain much performance from swappng to an aftermarket intake manifold and that destroys the angle which you're claiming so greatly increases the flow over a 1g stock setup. I'm not flaming you. But there's yet no proof.

Now, I'm not disputing what these guys are suggesting in that thread which is that a 2g head has the potential to out flow a 1g head w/ the proper port work:

http://www.dsmtuners.com/forums/showpost.php?p=1366740&postcount=48
http://www.dsmtuners.com/forums/showpost.php?p=1367152&postcount=49
http://www.dsmtuners.com/forums/showpost.php?p=1370102&postcount=52

After all, I did say. . .

That's not to say that a built 2g head is inferior to a 1G head. After all, you DO now have enough "meat" to actually get good port work done. Looking at the 1g head intake runners, it seams that we actually need some welding up to get the runners to flow better. . .