2g head on a 1g block

[bling5tatus]

To answer your question, I don't think you should use one... I think you should use what you've got... because you already know that it is the best for what you're doing.

No comparison necessary when you already know what's better right?

 

[dsm-onster]

Thanx for not giving any proof to back your claims. Talk about fail. Please show a little maturity when posting in this forum. You'll have to quote me claiming the 1g head was superior. I don't recall that. I recall claiming there are advangates that could cancel negatives and there could be negatives that could cancel advantages on both designs. And I recall asking the same questions the op was asking which is not answered.

So does anyone else have any DIRECT comparisons? Like 1g head and smim vs. 2g head and same brand and type smim.

 

[bling5tatus]

I'm sorry for not being able to bring more facts to the debate. I've only based what I said off of my own personal experience and my car has never been on the dyno so I'm not sure where the power shifted. I can say that the power did not feel like it was less up top w/ the 2g head... but it definitely gave me about 500rpm faster spool.

I would love to see a comparison w/ the same motor and just a head swap... but the intake manifolds would have to hold the same volume and match the ports on the head... to be fair. Do any of the smim's offer this?

I definitely agree that the two heads are good for two different things. My car is not a race car, it is a street driven car and is my daily driver... so that was my reasoning behind using the head that I used. I don't think that anyone should use the same method I have or that they should do anything a certain way.

 

[GPTourer]

As you can see from the part number list the EVO III cyl. head has a diff part number then the 2g head

This. So does anyone know what the difference in a 2G head an Evo III head is?

I was under the impression that the 2G head was designed for better torque and midrange power for a 200-300hp car and 16G class turbo. I never really believed it was built around the T25 since I assumed the head was the same as the EVO III and that Mitsu wouldn't compromise the design just for the mostly American market DSM. But if the heads are different, maybe they did keep the best for home.

A head thats good for 1000hp is not the best choice for 300hp is it? So I think its entirely possible that the 2G design is the best choice for most of us running 600hp or less, but if you have to have 700, 800, 900, 1000hp then just maybe the biggest ports are best in that of the 1G.

 

[v8killer]

i have had 5 1g cars and i own and drive a 2g tsi and the 2g wins hands down. it's just a overall funner car to drive than the wait till it spools here we finally go feel with the 1g cars ! it has more torque and revs alot faster than the older 1g.now i'm not saying it has all to do with the 2g head it could also be the fact that it's 8.5:1 compression also. i have a 1g head and intake on the shelf that i thought about swaping later after i put the fp green on and test the 2g head and intake out first before the swap. just my .02

 

[bling5tatus]

This. So does anyone know what the difference in a 2G head an Evo III head is?

I was under the impression that the 2G head was designed for better torque and midrange power for a 200-300hp car and 16G class turbo. I never really believed it was built around the T25 since I assumed the head was the same as the EVO III and that Mitsu wouldn't compromise the design just for the mostly American market DSM. But if the heads are different, maybe they did keep the best for home.

A head thats good for 1000hp is not the best choice for 300hp is it? So I think its entirely possible that the 2G design is the best choice for most of us running 600hp or less, but if you have to have 700, 800, 900, 1000hp then just maybe the biggest ports are best in that of the 1G.

Japanese Evo Heads have G6K stamped on the head on the thermostat side right below the valve body on the outside of the head.... 2g USDM heads have G6S (both 98/99 heads I have have G6S stamps...)

I hear that there is also a small port head that is G6C.. .but i dunno what car that comes off of... and I'm not sure of the differences between G6S/K... it may be head stud size amongst other things.

 

[dsm-onster]

^^^Probably the 4g61 turbo colt head.

I would love to see a comparison w/ the same motor and just a head swap... but the intake manifolds would have to hold the same volume and match the ports on the head... to be fair. Do any of the smim's offer this?

Good point. But if that is the closest you can get to a direct comparison then that's all we need. Since we must use the 2g head the way it is and the 1g head the way it is for a direct comparison, the best thing for the 2g head would be race manifold runners designed to match the 2g head; and the same would go for the 1g head. If the larger ports of the 1g head give an unfair advantage to the build with the manifold even though the runner length is the same and plenum is the same, well then that means the 1g has the advantage. The same goes with the 2g head and narrower runners for velocity.

 

[bling5tatus]

cams would have to be equal too... you couldn't use 2g turbo cams in the 2g head and 1g turbo cams in the 1g head because they're different.

I think if the two intakes have the exact same design and hold he same amount of fluid/air/whatever... and the intake ports match the head... and the cams are the same in both heads then it's a good comparison... now all we need is someone that has the parts to do this and a dyno/time to do it.

 

[pneumo]

I know a few things. Hopefully my answers will raise some good questions in this thread.

Why does velocity matter? In steady state flow it's better to have lower velocity because it's synonymous with pressure drop: lower is better.

In pulsed flow, such as the intake manifold, more velocity is better because velocity gives the air momentum. With momentum the incoming air charge will continue to fill the cylinder as the intake valve is closing and the piston is moving upward. Cams should be optimized to take advantage of this by delaying intake valve closing.

I don't think a 1G vs. 2G head comparison can be done fairly since the two port designs favor different cam designs. Consider also the different intake manifold designs that each head requires, and I think you'll begin to see that this debate over which head is better balloons into a debate over which system is better. In other words, it's not about which individual part works better, but which combination works better.

Rumor has it that the 1G head has large ports because it was designed to match the Cyclone IM, which has two separate runners per cylinder. The two runners merge just before the head, and the 1G head port was enlarged to blend with the enlarged area where the two runners merge.

 

[dsm-onster]

I don't think a 1G vs. 2G head comparison can be done fairly since the two port designs favor different cam designs. Consider also the different intake manifold designs that each head requires, and I think you'll begin to see that this debate over which head is better balloons into a debate over which system is better. In other words, it's not about which individual part works better, but which combination works better.

This is exactly what I was thinking but finding no good way to say it.

 

[MichaelSuch]

I'm in the middle of this swap on my '90 GSX and need a little help. Where can I mount my 1g Coil pack and power transistor? The holes on the 2g intake manifold don't line up, I could mount both of them with just one bolt but that would be a little ghetto looking. Where has everyone else mounted theirs to? I'm using 2g head, 2g intake, 2g exhaust, 1g Coil pack and power transistor.. Thanks for the help.

 

[Afroclipse]

Hey you SOB this s*** was getting good, where is all the flow bench proof and S***, WTF I was entertained and not appreciating the end. Its like a movie ending just before the final confrontation, either you give me more or Dsm-onster I'm going to treat you like a Nazi and I'm in the killing Nazi business.

 

[dsm-onster]

Internet threat

This is open for whatever ending you want. We still need someone bothered enough by the ports shapes to do a test.

 

[donniekak]

Someone on here did a flow test on stock 1g heads, we need a 2g example.

 

[kiggly]

I will state this for everybody to have fun with.

Flowbench numbers mean very little for what power a port will make. I'm planning to re-test a lower-flowing head later this season. The higher flowing head (280+cfm vs ~240cfm) doesn't seem to make any more power and may actually make less.

Kevin

 

[Zex4g63]

I will state this for everybody to have fun with.

Flowbench numbers mean very little for what power a port will make. I'm planning to re-test a lower-flowing head later this season. The higher flowing head (280+cfm vs ~240cfm) doesn't seem to make any more power and may actually make less.

Kevin

And kiggly nails it on the head.....

 

[dsm-onster]

So no reason for the test I guess, right?

BTW, I think the 2g head will win with the back to back horsepower pulls

 

[Zex4g63]

The test is flawed. The power is from finding the correct combination of parts for what you are trying to accomplish, which doesn't always work on the dyno as compared to the flowbench numbers. The flow bench is just a tool not the end all. As a matter a fact the flow bench has sent many people in the wrong direction. Someone has made over a 1000hp with each variation of the head, so it's not the limiting factor for most people here. Like I said , the power is in the combination of parts, not any single part. If we're not all gonna buy the same parts than the results of a test don't matter.

 

[dsm-onster]

Thus, there's no reason to swap to a 2g head if you have a 1g car. Just build with the 1g head ports in mind. . . is that your premise???

 

[donniekak]

My combo i keep going back to for street driving is a 2g head with my g4cs manifold. I honestly don't see much of a difference up top, but the throttle response and off boost driveability is better.

 

[caliboy23]

I've seen the numbers corresponding to this subject before. In order to see any additional gains by switching to a 2G head you would need to be at a power level most of us have never experienced nor ever will experience. Plus EXTENSIVE port work would need to be utilized to make the 2G head do what the 1G head already does without port work. Remember these are turbo engines where the air is FORCED into the motor. So whatever VOLUME of air your turbo system can produce will be the volume of air that's shoved down the throat of the motor. If your parts can produce X amount of volume and your head was designed to move less volume at a higher velocity, then your obvious bottle neck is the head. If we were talking about an all motor application the answer would obviously be way different.

A side note to remember is that the new heads with smaller ports are more for the Smog Nazi's and fuel economy than they are for performance. That's why hollow cams and Mivec are passed off as performance upgrades while the highest horsepower 4G63's came from the 1G DSM. Ask John Shepard if he would ever put a 4B11 or Evo 8 4G63 into his car.

So is the 2G head better than the 1G head? It might be for 1 in 10,000 of us. If he decides to go that route of course. But the simple fact is that anything a 2G head can handle, a 1G could, and it would cost less.

 

[BeatupVR4]

Its almost as comical that they are comparing the 2g head to an evo 8 head....Cathedral port design (that kicks ass) versus small ass 2g design (that is significantlly suckier than the EVO).


Joe

Not trying to start a flame war but I'm almost positive that Evo heads are NOT a cathedral design. The runners on the intake manifold are completely rectangular as well as the ports on the head and VERY similar in size to a 2G head. The "cathedral" that you are thinking about is only a relief for the injector nozzles as on an Evo the injectors are mounted on the intake manifold itself and not on the head.

If you look an inch into the port of an Evo head it turns right back into a rectangle. Also if you were to "shave" an inch or so off a 2G head into where the injector mounts it would have the same 'cathedral" shape port as an Evo head.

EDIT: Lol just realized the quote was from the first page.

 

[kiggly]

hollow cams and Mivec are passed off as performance upgrades

This is just a total load. Hollow cams are for weight reduction in almost every production car, or in some cases to use different lobe materials for different lobes (switching profile stuff).

How in the world can you guess a MIVEC setup isn't for improving performance? Do you know what it does? Every engine speed has a different optimum cam timing. If you can optimize cam timing everywhere, it is most certainly a performance upgrade. There are large emissions benefits as well, but the performance gains can be huge.

I know the 1g vs 2g head debate won't die and people can't get past the fact that a 1g port is bigger so they think it is better. I'm just not interesting in arguing on this topic anymore. I will put this out there:

The quickest DSM on gas is running a 2g head (mine, on near-stock sized ports)
The second-quickest 4g63 is running a 2g head (the Neimczyk's rail car, also on near-stock sized ports)

Kevin

 

[dsm-onster]

I'll never argue with you Kevin . Fuel doesnt matter too much in the flow debate, though. The fastest 4g63 runs a 1g head and so does Shep

But I've since looked at your posts on the link forums concerning the 2g head. And I see it works well. And I'm starting to come around, especially since, through your actual testing, you said that a small port head seams to 'make better use of big cams', and seams to do better throughout 6-9.5k with your 2.0L setup.

 

[91stocker]

Is there any more info on the 1g vs 2g head topic? Ive had the argument brought up to me and it seems to be a wash, just run what you have deal. am i wrong?