Yes, yes I know that a 1g head is obviously has bigger ports, but in this case is bigger better. If I accept as fact that the more I port a head the more low-end I lose (correct me if I am wrong). Working with that I mind, I would think that a 2g head will work better suited for a small turbo (a 16g in this case) efficiency range than a 1g head. All other spec of the car will be to factory specs other than the fueling. Is my theory flawed? At what point does a 1g head out shine a 2g?

Well, both stock heads are designed to work with the factory turbos to make more than sufficient low-end from the factory. Comparing the 1g to the 2g head, whatever low-end the 1g head might be losing is nothing close to the differance it has in top-end over a 2g head. Now keeping that in mind... a evo3 16g is going to out flow the stock 14b nevermind the t28 in the upper reaches of your rpm band and still pretty much spool just as quickly. Think theres a flow chart i saw somewere were a 14b flows about 420ish cfms at 15psi while a evo3 will flow close to 560cfms at the same boost, yet has a 200-300rpm spool differance. Anyways, point at hand.. whats more important to you? A slightly more torque low-end but that nice and lame feel of the power just subsiding at 6000rpms.. OR a similiar torquey low-end but power to red-line? If i were you, I'd go 1g head and even opt to have it midly ported with a angled valve job, since your considering a head change anyway. You're not gonna lose much low-end especially on a small turbo, but your gonna want the top-end. Goodluck

i strongly suggest the 1g head, i have a ported 1g head with a 3 angle valve job, with the evo 3 16g, my low end torque is phenominal, 26psi by a little after 3100rpms in most cases.

I like to think back to this thread when considering the "1G head vs. 2G head" discussion. Take it for what it's worth.

The 1g head flows more volume, hence the bigger ports. The 2g head has smaller ports but the flow pattern is much better. 1g flows more, 2g flows better.


Joe
Slowboy Racing

At what point will the flow limitations of the 2g head cause a bottle neck in airflow? Thats the real question.. And will the noticability be there with a 44lb/min MAX turbo? I would consider the 2g TB/intake manafold as bottleneck before the head.

scottsee said:

I would consider the 2g TB/intake manafold as bottleneck before the head.

Click to expand...

But of course, although that's not really the point. Restrictions and ID reductions and such will have a significant effect on the capabilities of any head. Just in terms of your example, I think we have to assume (at the very least) a 1G intake manifold and TB is being utilized (and of course, other appropriate upgrades have also been made).

But I digress... I fully agree with the rest of what you said.

this has been hashed since the beginning of time...I am all about port velocity vs. port volume, Injectors aiming at intake valves vs port floors.

But do what you want.

i wouldnt throw a 1g head on a 2g unless you have dsmlink. most people have idle issues when wiring a 1g cam angle sensor to the 2g harness. it can only be fixed with dsmlink or a similar program (aem..etc..). ive also seen some people wiring in a 1g cas without dsmlink and be totally fine. its a mixed bag.