1g or Ported 2g Cylinder Head? 14b

[scottsee]

Because I have 2 spare 1g heads laying around the garage and I was really intrested in doing a 1g head swap. SoI fliped through the yellow's and asked for refurals around town for the best cylinder head service machineshop in town. Everyone pointed me in the same dirrection. So I call "Cylinder Head Services" ( dumb name but easy to reamber) up and tell them I'm looking to get a 4g63 twore down, hot tankes, pressure checked, 3deg angle job, RA30 for a Cometic head gasket and check to see if all my valvetrain is within factory spec. It will cost me $185. In think'n "not bad!". So I ask him about porting, he says a port and polish job will cost $125 to match up the intake to the runners, port the exhasut 5mm and mirror shine it up. Immeiditly I think of the 120k 2g head I have on my car right now. You know where I'm going with this. 1g tb/intake on ported and polished 2g head....

What do you guys think?? Should I have a 1g head or my 2g head done? Good prices? should I shop around a bit more? The reasion im asking is becasue we all know the 2g head is more effecent, but designed for higher airflow volosity in low/mid rpms with crappy #'s uptop... Porthed out to the 1g specs you would think their would be no need for the 1g's shitty flow design. I havn't seen any 2g ported cylinderhead flow #'s posted around here. Anyone have any links, or able to chime in what would be best for me??... Thanks.

Ps. I havn't updated my profile. Stock 7bolt, dsmlink, 14b.
Thanks...

 

[blcknspo0ln]

those prices sound pretty good to me. I got raped by a local machine shop for 300 to do a basic hot tank/new valve seal/mill job. Anyway, there are many interesting debates about 1g vs 2g heads floating around here in the tech forums. Just to give you a quick reference: a 1g head plain flows more (also debated upon) and a 2g head has smaller ports to encourage higher velocity. FYI, some hardcore racers are switching to ported 2g heads on their motors now.

 

[scottsee]

Yeah.. I've been seeing the switch going on myself. I have a feeling it has to do with the 2g more superiour design. There is just no substitue for effency. Thats why the 2g head sees a lower max timing of 16 deg above 2.1g/rev compared to the 1g Very high timing. Same has to be said about the EVO's more effecent degine.. Even less peak timing, somthing like 12.

 

[CanadianTSi]

I'd stick with the 2g head. Also you don't really need it ported unless you plan on pushing alot of Horsepower.

 

[nanokpsi]

Keep in mind that all that people switchng to 2g heads only do so becasue there is more material to remove. This will let a very experienced porter get the best shape for the ports. Your local head shop will not be able to give you this kind of job. For a basic job/head shop just get the 1g head rebuilt. Its pretty common to pick up 2lb/min at the 40 lb/min level just switching to the 1g head/intake.

As for the timing, I am sure it has far more to do with the engine's compression ratio than it does cylinder head design.

 

[shleppy]

I thought it was more like an additional 4lb/min with the 1g head-at least that's what I've read many times on the dsmlink forums, and also in the turbo education sticky.

 

[1fast97gsx]

I believe the best thing to get is a ported 2g head, however if you aren't going all out a stock rebuilt 1g hed is more then enough, hell even a 2g head is more than enough. What are your goals?

 

[nanokpsi]

Personally, I wouldn't let just any place port a cylinder head. Sure, you may increase flow, but losing velocity will negate much of the gains you may see. My point is just as much harm can be done as good in cylinder head porting. Not to mention the 1g route will be cheaper and give a known performance gain.

 

[scottsee]

I believe the best thing to get is a ported 2g head, however if you aren't going all out a stock rebuilt 1g hed is more then enough, hell even a 2g head is more than enough. What are your goals?

Short handed goals are 300whp on a 14b with dsmlink.

 

[Enraged78]

Short handed goals are 300whp on a 14b with dsmlink.

This is possible without any head given the right supporting mods. With a frontmount, fuel mods, water injection, etc., this would be a walk in the park. Do you want 300Whp on race gas, or pump gas? Anyway, with these remarks out of the way, here are my experiences.

I've had a stock 2G head, ported 2G head with 1G intake manifold, and 1G head on my car with the same mods on it. (Please don't ask why). The 2G head was nice, but the ported head was better. I lost a little bit of turbo spool with the ported head (probably more due to the intake manifold, but whatever), but DSMLink reported a little more Lb/Min up top. The ports on the 2G head were decent, and done on a flow bench by a reputable shop. The 1G head was better than the ported 2G head I had, but lost a little more RPM to spool. Originally, I spooled my Evo III GT at 2750 on the ported head. It gets full boost by a hair under 2900 on the 1G head. However, the feeling the car gets as the tach passes 5,200 RPM is incredible.

Anyway, with this out, here are the pro's and cons.
A 2G head will bolt up stock, and has more 'meat' in the head, allowing for some very crazy port work on a flow bench if your wallet allows it. 2G heads can be made to flow more than a 1G head, but will take a very competent and patient machinist. Once the port work is done, you will have a very quality race head on your hands. You get to keep your cam and crank sensors if you want to, but you should definately upgrade your intake manifold.

A 1G head will not bolt up stock (needs to be machined to fit the studs and dowels properly), but already has more material removed than even a mild port 2G head. It will have the factory cast flash, allowing for better air/fuel tumble into the combustion chamber. Your EGR will not function the same way, and if you block it off, you will lose a small amount of fuel econony(you should do that anyway, though). You will have the option to use the 1G CAS, which is a good thing. You can now control your base timing with relative ease. The 1G head does not have the two 14mm studs on the exhaust manifold, and many people like to have these in installed on their 1G head.

Anyway, the long and short of this is that for your HP goals, either head would do just fine, as would the head you have now. Put your money towards something more worthwhile, unless you plan to go really big later. Remember, people have broken into the 11's on the stock 2G head, and the smaller ports of the 2G head do help your turbo spool faster.

Matt.

 

[scottsee]

Thanks for the input. I had always thought the 1g head swap didn't require any special machining to be installed properly. Thanks.

 

[dsm-onster]

Keep in mind that all that people switchng to 2g heads only do so becasue there is more material to remove. This will let a very experienced porter get the best shape for the ports. Your local head shop will not be able to give you this kind of job. For a basic job/head shop just get the 1g head rebuilt. Its pretty common to pick up 2lb/min at the 40 lb/min level just switching to the 1g head/intake.

As for the timing, I am sure it has far more to do with the engine's compression ratio than it does cylinder head design.

You hit the nail on the head. Find a head guy that knows his 4g63 heads. . . Not a guy that knows his machines that modify engine heads. Does this machinist flowbench while machining your head to achieve the best results? If no get another machinist or go with a 1g head AND 1G intake mani or matching smim. An experienced porter will know what to do with the extra meat on the 2g head.

Anyone else is just fÜcking with playdough at recess .