2g head on a 1g block

[DSMunknown]

I was always under the impression the 1g head was built more towards top end, and the 2g head towards low-midrange torque because of the t25. Like you guys said though, the ports on a 1g are pretty big. I've never had a 2g head laying around that I could compare with though.

Look through this old thread for some opinions that would reverberate your statement.

 

[gijoe985]

I thought this post would add to the discussion.

I did a lot of searching around with this when i was testing the flow results on my 6 bolt head on a flow bench. I was never able to get my hands on the 7 bolt head to do side by side testing for numbers, but i did see one. The 7 bolt head has a much better design for the air to flow into the combustion chamber, and on top of that the casting is much better. Its a more shallow floor compared to a 6 bolt head so the air has a much smoother path of travel, whereas the 6 bolt runner floors are much higher and have more of an angle for the air path to follow. The 7 bolt flows "better" but does not flow as much volume as the 6 bolt. Regardless you would see more gains with a 6 bolt head over a 7 bolt. Plus, i may be wrong in assuming this, but a turbo is a means of forced induction...forcing air into the equation. If there is a larger port for more air to be forced into, the more gains you will see. I would clean up the bowels and casting imperfections before you slap it on, if you do opt for the 6 bolt head...you'll gain almost 30 cfm per cylinder if you do. Also if you do the 7 bolt head, you will need to drill out the ead bolt holes 1mm to fit the 6 bolt's.


Joe

 

[SBR Joe]

It is absolutely comical that all those who post and boast the 2g head being better all say you have to port it. Is it a bolt-on upgrade to the 1g block? Not at ALL!!!! Not one soul has proven it is.

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

 

[dsm-onster]

Just because my name is in red, I always have to 'prove myself' whenever I post so I didn't even delve into this. . .

 

[gijoe985]

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).

Describe cathedral port desgin. Sounds cool.

Thanks.

 

[SBR Joe]

Cathedral Port Design (EVO8)


Regular 1g head (no cathedral ports)

This design is used alot in the v8 world (thats how i found out about the term when i was doing work on a honda b series head in school), they take the intake runner and upen up the top of them that makes the "cathedral" appearance. It provedes good velocity thus crating good low end torque, granite the evo has MUCH larger runners resulting in top end performance as well, but it creates the same cocept. Hondas have the same head design also and flow very well from the factory. A big debate in the v8 world is wether they flow better or worse than your conventional squarre port runners...but tose kind of heads are a whole different ballgame.


Joe

 

[ZmanIV]

Are you sure that pic #2 is a 2G head? Those ports look huge.

 

[SBR Joe]

Are you sure that pic #2 is a 2G head? Those ports look huge.

Oops, i think i copied the wrong link..., ill fix.

joe

 

[Siral3x]

Cathedral port design??HMMM...for some reason I tought the evo uses that design because of the injectors are squirting fuel at a diff angle then the 1g/2gs...thus a better air/fuel mixture and flow...
Can anyone confirm ???
As far as I'm concerned Mitsubishi never made a 97 ECLIPSE GSX in Europe, so whatever you saw making 680HP it's hard to belive it was a GSX! As a matter a fact the only 2G specs ever made in Europe were N/A with EVO III style intake manifolds...never was produced a GSX!
For people interested in running EVO III intake manifolds I got bad news....the manifold will bolt up but the TB and TB cable are on oposite sides then 1g/2g cars. Unless you are gonna custom hack/adjust your throttle cable you can't use it. Bolting different TB will not work either bc you will get leaks and the bores are different. There is a aftermarket HKS TB that will work tough....Overall it is too expensive!

 

[Pj97GST]

As far as I'm concerned Mitsubishi never made a 97 ECLIPSE GSX in Europe, so whatever you saw making 680HP it's hard to belive it was a GSX! As a matter a fact the only 2G specs ever made in Europe were N/A with EVO III style intake manifolds...never was produced a GSX!
For people interested in running EVO III intake manifolds I got bad news....the manifold will bolt up but the TB and TB cable are on oposite sides then 1g/2g cars. Unless you are gonna custom hack/adjust your throttle cable you can't use it. Bolting different TB will not work either bc you will get leaks and the bores are different. There is a aftermarket HKS TB that will work tough....Overall it is too expensive!

You should check your sources.. First and foremost; Mitsubishi DID eventually release the turbo cars in Europe during the last few years. Second, lots of them were imported privately. Think of how many military guys brought their 1G and 2G's there..

As far as the Evo III manifolds being backwards... Where did you gather that brilliant hypothesis? The Evo I, II, III's and DSM's shared the exact engine orientation. The motor got flipped to the current orientation (Timing belt on Passenger side) with the intro of the Evo IV.

Thanks for playing.

 

[Siral3x]

You should check your sources.. First and foremost; Mitsubishi DID eventually release the turbo cars in Europe during the last few years. Second, lots of them were imported privately. Think of how many military guys brought their 1G and 2G's there..

As far as the Evo III manifolds being backwards... Where did you gather that brilliant hypothesis? The Evo I, II, III's and DSM's shared the exact engine orientation. The motor got flipped to the current orientation (Timing belt on Passenger side) with the intro of the Evo IV.

Thanks for playing.

"the manifold will bolt up but the TB and TB cable are on oposite sides then 1g/2g cars."
I meant the TB is oriented different on the evo III, not the manifold itself! Also the evo III TB doesn't have a TB ELBOW LIKE 1G/2G CARS! The throttle cable, and bracket on the intake manifold are also different. I will post a close pic of my evo III engine bay smartass!

For the 17 years I have lived in Europe all turbo ECLIPSES were impoted from U.S or the stock 4g63 7 bolt N/A was swapped with a US spec turbo. So please send me a link where I could read and learn about these phantom GSX's made in EUROPE!!

 

[Siral3x]

Hey Pj97GST take a look at these:
eurospec inst. cluster

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eurospec ONLY 2.0L 4g63 7 bolt DOHC NON TURBO!!!

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eurospec tail lights:

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[Siral3x]

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[gob4sho89]

Dude, when did I say that it was made in Europe? WTF

 

[beating4g63s]

will you to get back to the subject at hand of 2g head on 1g block, if no input on subject keep it out, not trying to be defiant or anything but I've been planning on using this setup and would rather know more about it then euro spec dsms I mean who cares which one of you are right.

 

[pneumo]

Cathedral port design??HMMM...for some reason I tought the evo uses that design because of the injectors are squirting fuel at a diff angle then the 1g/2gs...thus a better air/fuel mixture and flow...
Can anyone confirm ???

Yes, you got something there. The injectors on the evo 8 are mounted at the top of the intake manifold because the ports are higher. The 1G has injectors mounted in the head, so the gasket surface looks square.

You have to look beyond the gasket surface.

Here's a pic looking up in a 1G head. Just imagine if you sliced the gasket surface back by one inch. I bet the shape would look a lot like the evo head pic except for port height and size.

 

[Boo5t_Addict]

A 1g head has larger intake ports, which (in a simplified expression) will most likely produce more peak power. However, a 2g head has a much straighter pathway for the air to move into the combustion chamber, and this will most likely produce better velocity throughout the rpm band. I guess what I'm saying is, you could use a 1g head for a slightly higher peak power output, or a 2g head for less peak, but more area under the curve. Why do I say this? Because in cylinder heads velocity is the name of the game.
Even in NASCAR V8's, the cylinder ports are somewhat small, but the velocity of incoming/outgoing air through the head is fantastic. 700 restricted horsepower from an N/A v8 spinning 10k rpm's is no joke. Modified magazine actually used a 2g head on their project 2g awd Talon (with a 6-bolt block swap) for these very reasons. If you can get a hold of a back issue they mention craving velocity over volume. At the end of the article they mention an interest in doing a stroker out of the 6-bolt in the future (anyone know if they ever actually did it?), but do not mention any interest in switching to a 1g head. Take my opinions with a grain of salt, as it's late, I'm bored, and in much need of sleep.

 

[wishihadatalon]

"the manifold will bolt up but the TB and TB cable are on oposite sides then 1g/2g cars."
I meant the TB is oriented different on the evo III, not the manifold itself! Also the evo III TB doesn't have a TB ELBOW LIKE 1G/2G CARS! The throttle cable, and bracket on the intake manifold are also different. I will post a close pic of my evo III engine bay smartass!

For the 17 years I have lived in Europe all turbo ECLIPSES were impoted from U.S or the stock 4g63 7 bolt N/A was swapped with a US spec turbo. So please send me a link where I could read and learn about these phantom GSX's made in EUROPE!!

Please explain, because I am looking at an evo 3 intake manifold right now and the only thing different for a throttle body, is the size of the opening. The ears for the throttle cable are still on the back, not on the FRONT of the plenum. Also from the looks of pictures that I have found online, the throttle body closely resembles a n/t throttle body. Just because it doesn't use an elbow doesn't mean it wont work. Evo 3 manifolds have been used by dsmers for many years.

 

[gijoe985]

This is why I wish I could see some dyno sheets from someone with too much time and money. Bolt the 1g head on, do the run, then bolt the 2g head on. Maybe play with intakes as well. Each side has their own argument and both seem very convincing to me. I'm still 100%, officially, undoubtedly, undecided... I've just got to continue my research. The more I learn about both the more interesting it gets.

I guess it gets down to the correlation between velocity, max flow, and how much power they produce.

Does anyone know how to factor forced induction into one of those calculations that figures required airflow? I assume those formulas were made for NA engines.

 

[BOOSTIN21]

i dont see any point into arguing the 1g as a more dominant head design. it has already been proven (in my eyes) that the 2g has a more technical and proper design. it is almost the same as a late model EVO head. the only argument that i see from 1g head supporters is the, big ports=moer power and flow, which was already proven to be false.

i drew my conclusion a few years ago and the next motor i would build would be 6bolt bottom end with 2g head. rumor had it a while back that Shep used a 2g head and so did Sean Glazer. but that could be hear say.

i say if you want to factor in forced induction read some compressor maps for certain turbos and trim sizes, there has to be a math to figure it out.
cullen

 

[DSMunknown]

For people interested in running EVO III intake manifolds I got bad news....the manifold will bolt up but the TB and TB cable are on oposite sides then 1g/2g cars. Unless you are gonna custom hack/adjust your throttle cable you can't use it. Bolting different TB will not work either bc you will get leaks and the bores are different. There is a aftermarket HKS TB that will work tough....Overall it is too expensive!

Please explain. I have a 1G 60mm TB and it lines up perfectly with my E3 IM plenum.

 

[beating4g63s]

I hope I can end this question as I was thinking, if john shepard or sorry don't know his real name but (evil_eagle) can chime and and tell us which head they use, I will say this which ever one they use then that would be the best one, if it's good for 7s and 9s then it's good for the rest of us. Hopefully either one can chime in. or if anyone knows from first hand experience which they are using.

 

[wishihadatalon]

I hope I can end this question as I was thinking, if john shepard or sorry don't know his real name but (evil_eagle) can chime and and tell us which head they use, I will say this which ever one they use then that would be the best one, if it's good for 7s and 9s then it's good for the rest of us. Hopefully either one can chime in. or if anyone knows from first hand experience which they are using.

Jake runs a 1g head. But Jake also runs his car out to 10k and runs a very large turbo. The 2g head wasn't made for that, but there are ways to make it do that, while retaining all of the benefits of the 2g head. You will most likely be paying quite a bit for it but it would be worth it.

Also remember, something that is good for one person, isn't always good for everyone else

 

[Pj97GST]

Completely off topic, but Siral; You never heard me say that they "made" any in Europe. I said that they were imported, meaning brought into European nations and then sold there. I personally know of 3 2G GS-T's and 2 GS-X's that were bought in Europe. (Germany, Sweden, and Austria.)

But anyways, who cares? Back to the topic at hand.

 

[gijoe985]

But anyways, who cares? Back to the topic at hand.

Yeah... so the Hawks beat the Redskins... Go Hawks!!!