Port the 2G head, or go with the 1G?

[inatalonIXLR8]

Is there any benifit to keeping the 2G head on my 95 Tsi? The car is mainly street driven, and I'm gearing it towards autocross racing next summer. I understand that the intake manifold and head from the 1G have better flow, but is torque affected by the larger apertures?

My next question is that I've ordered 1 mm oversized Ferrea valves, springs and retainers for the 2G head already. Are they compatible with the 1G head?

Future plans are to put a stroker kit in next summer. Would this affect my decision to opt for the better flowing head, especially when moving that much more air and exhaust?

Lastly, are there any common problems associated with the switch? About the only thing I know is that you have to move the cam sensor. To where I'm not sure.

Thanks for everyones help.

I just checked out the info at www.roadraceengineering.com Lots of good stuff there, but what would you guys do?

[kjewer1]

Here is my take on it. Porting a 2g head to get more power than a stock head is not easy to do, and the gains are going to be minimal unless going with a full professional race head worth a few thousand dollars. The 1g head is a no brainer bolt on upgrade. I saw a 3 lbs/min increase in airflow when making the swap, on a relatively mild setup no less. I can imagine the added 15-20% airflow from the stroker seeing a more dramatic increase.

Another point is that the 2g head is "smaller" than the 1g head on a 2 liter, would does it look like on a 2.4 liter? Is the 1g head now the "smaller" head for a stroker? Hopefully you see my point.

If you said this was for drag racing, I would say 1g head hands down as the best option for your hard earned money. But seeing that this is primarily going to be a street/autox car, the smaller head may make more sense. That's a gamble you can take as you will. I can't speak from experience here being a street/drag type only

The valves and other parts should all be interchangeable as far as I can recall. The cas thing can be tough on 95-96s. Aside from welding up the head as RRE outlines, the simple fix is to use a 1g CAS. I believe if you stick with the 2g block's crank sensor and use the 1g cas only for the cam signal, you won't have the RM CEL issue, but I can't be sure. If you end up with the RM CEL the best thing to do is really to just get DSMlink. The baro wire mod and AFC combo work, but you're lying to the ECUs several different ways, and I couldn't get comfortable with that at anything over 16g or so airflow levels. Having a 95 and most likely an EPROM ECU (I was unlucky), DSMlink is an absolute no brainer anyway.

[inatalonIXLR8]

Thanks for sharing that wealth of information, I appreciate it.

[inatalonIXLR8]

Anyone else have a view on this?

[Thor06]

I'd go 1g, 3lbs/min seems like too much airflow to pass up IMO.

[blk_srt]

Isn't it true that with a good port job a 2g head can out flow a 1g? This summer I'm taking a class on head porting so I was wondering if I could just port out my head and see good results

[kjewer1]

The only reason that the 2g head has this potential after being ported is because the ports are so ridiculously small, it's basically a blank canvas. So you have the oppurtunity to basically build the ports from scratch. There are only a handful of people in the world that know our heads well enough to do this properly. My guess is that all the other half assed attempts at this result in a head that no longer flows as good in the midrange as the 2g head did and still doesn't flow as well on the top end as a mildly cleaned up 1g head.

[blk_srt]

I also will have access to a flow bench and the instructor has 20+ years under his belt so I'm interested to see what I can pull off and maybe if I get it right I'll make a template and offer port jobs

[kjewer1]

There is no way to make a template, since all the important work is done well inside the runner/bowl. A template will work just for the inlet of the intake runner and the outlet of the exhaust runner, and work here has a negligible effect. It really isn't something that is easily done, even by people that have worked V8 heads for example for a long time. But, don't let that stop you. It's sure to be a good learning oppurtunity. But I would not expect it to perform better than a stock 1g head with some mild cleanup work. In fact, this is more of a project the slightly more knowledgeable person can get away with. A mild cleaup and gasket match on the 1g head. Even I am willing to attempt this, I have done half a dozen or so heads with good results ("good" meaning that I didn't noticeably or measureably HURT power output ). But a pretty good understanding of fluid dynamics is almost required if you intend to improve on what the factory has put thousands of hours, dollars, and intelligent poeple into creating.

[inatalonIXLR8]

Any ideas why the designers decided to go this route? Did they put a small turbo / intake / T.B. / and head just to bring up the bottom end power? Or maybe it helped the 0-60 and spool up times.

[kjewer1]

Your first idea is correct. They wanted to make it feel like it wasnt a "turbo car." Unfortunately the public are a bunch of pussies and the 1g was a little too much like a "turbo car." Since 0-60 implies a launching technique of some sort, spool up isn't really an issue. 0-60 testing is however the reason that 2nd gear always ends around 60.