Port and Polish Heads

[Spike28278]

Anywhere in melbourne to get heads ported and polished? and whats the rough price?

Or are there any GR heads for sale that have been ported?

[bjk]

[spetz]

From what I have been told (so just hearsay) the 6A13TT heads flow really well (better than the MIVEC heads) and you can use the 6A12 DOHC cams from the GR to have an NA profile on them.

Might be more worthwhile using the 6A13TT heads rather than porting the 6A12 ones

[Daniel2019]

Don't bother. Can confirm from personal experience.

[spetz]

Daniel, you had GR heads ported?

I think a few members had MIVEC heads ported and made some decent power (along with other mods of course).

I have had mine ported and polished but no dyno runs yet however hopefully within a couple of months

[Vectose]

Daniel, you had GR heads ported?

I think a few members had MIVEC heads ported and made some decent power (along with other mods of course).

I have had mine ported and polished but no dyno runs yet however hopefully within a couple of months

Nope, he had MIVEC heads done.

[spetz]

Any accompanying mods if you know?

I recall someone else had them done and was happy with the results

[Daniel2019]

More placebo effect than anything I am sure of it.

I have an exhaust and an ARC intake. Also was on a freshly built engine. For the cost of removal and porting and all that.. just boost it.

[spetz]

There is also the added issue that the OP is talking about doing this to non-MIVEC heads

[Daniel2019]

Just... don't bother..

[Vectose]

Just boost.

Easy

[bjk]

Just boost.

Easy

Buy a Nissan

[Sahin]

Buy a car

[Mitsiman]

The mivec heads flow really really well with porting and 1mm oversize valves.

But only really necessary for naturally aspirated with camshafts.

We designed a valve and valve spring package for the FTO Mivec heads based off Erics Mad FTO

[spetz]

Would the OS valves and cams offer much gain on the stock bottom end running 98 fuel though?

[Mitsiman]

Yes they will due to the factory high compression nature of this vehicle. The trade off like anything is fuel economy and driveability, idle stability dependant upon how large you go on the camshafts. We tend to go for stock low rpm camshaft profiles for stockish vehicels and only change the high rpm lobes so as to not affect the vehicle too much for normal driving.

[slippercream]

Here's to resurrecting more threads. Does anyone have figures putting the MIVEC heads through a flowbench?

Would like to ideally know the max airflow on the heads at atmo, and any specific machining performed to increase VE. (Other than of course, the typical answers... P&P, extrude honing, etc.)

The best that I could find is +1mm osz ports and valves. But I haven't found any figures to substantiate any gains. Again, preferably at atmo.

I realize the 6A12 MIVEC isn't exactly built to handle huge amounts of HP, but to know what actual max airflow can be pushed out to each cylinder will help to scope the theoretical capacity of the heads (and engine) to apply to either an N/A build, or FI.

Thanks in advance.