Port and polishing advice needed

[Suprakeith]

Hello I have jspec n/a supra and have spare inlet manifold parts that am porting and polishing, now I understand about match porting that's all good. My question is it better to leave the Inlet parts rough on inside or using die grinder make them all nice and smooth? By inlet parts I mean the Y piece and both inlet manifold sections. I think polishing inside will be better option but unsure, so need some good advice please.

Thank you in advance for any advice

[Tricky-Ricky]

Smooth them by all means, but don't mirror polish the ports as this will cause the fuel to drop out of atomization, you need a slightly roughened finish, there is not much to be had power wise by doing this though.

[Chris Wilson]

This is the sort of finish you want (a re-worked port from my Skyline engine's head). I don't recommend you cut the guide right back like on this one, I use a special phosphor bronze guide material which wears well even on the shortened length. Definitely do not shorten the exhaust guides much, if at all, as they need to remove a LOT of heat from the valve stems on an engine, especially if you turbo it. If you haven't done porting before you can VERY easily scrap a good head, or make it flow worse than stock.

[Dnk]

I think all i'd do is match up the ports outline to the manifolds and leave it at that.

 

I did that on my 4.6 V8 RR engine as the miss match was huge on both the inlet

and exhaust.

[Suprakeith]

I wasn't planning to do anything to head at moment, just thought of improving the inlet parts while I can as they all been cleaned and have all ready polished the fuel rail and will either be painting or polishing inlet parts once done inside was just thinking of smoothing the inside using die grinder to help air flow plus hopefully next year be going na-t and will get better gains then

[Suprakeith]

Any body else got advice on this please as want to make sure before go ahead with it

[TheTurtleshead]

I would just make sure the ports are matched nicely Keith… It won't make any noticeable difference for the power you want to run mate..! Spend your time elsewhere.

[Noz]

Herb made 14bhp more on his mid bhp dyno. I think his top end was only 2hp, but that's a great improvement on power pick up. It's worth the effort for mid power but your never see massive gains without boost.

[Chris Wilson]

If a head exists which has been ported to a really high and known effective standard, or even just one pair of ports in a head, you should consider getting it CNC copied. A friend of mine specialises in this. Get a good porter to do one cylinder pairing, then CNC copy across the other ports. Some of the best porters are getting sniffy about this though. But you need something to copy, has anyone spent serious time on a flow bench and dyno with a 2JZ head? Hell, has anyone in the UK actually used a proper engine dyno for 2JZ development? Plenty of RB26DETT engines have been developed on engine dynos, but I have never seen any proper power graphs for 2JZ. Just adverts for 1200 BHP Supras on 1000 CC injectors, offered with a warranty

[Suprakeith]

Herb made 14bhp more on his mid bhp dyno. I think his top end was only 2hp, but that's a great improvement on power pick up. It's worth the effort for mid power but your never see massive gains without boost.

 

Not after massive gains at all, just thought while they sitting they may aswell take the time to make them more efficient.

 

Also agree with what Chris says as when had old ford had so much information on different ways to port head for different results it was easy, trying to find same information on 2jz head is proving to be impossible so far.

[Noz]

It may be less effort to go nitrous. I know a lot of people poo poo it. But if you just want a tiny bit extra, like 50hp it might be an idea to save you shed loads of time and money. Depends what you want to do.

[Chris Wilson]

Not after massive gains at all, just thought while they sitting they may aswell take the time to make them more efficient.

 

Also agree with what Chris says as when had old ford had so much information on different ways to port head for different results it was easy, trying to find same information on 2jz head is proving to be impossible so far.

 

 

I did have my porter take a look at a sectioned 2JZ-GTE head and he thought it was pretty good for a production casting. I seem to recall him thinking bigger exhaust valves and some exhaust port work might be good on a serious engine. No one has ever wanted to go that far though. Strange, as RB26DETT porting is commonplace and their ports aren't that bad as stock either.

[Suprakeith]

It may be less effort to go nitrous. I know a lot of people poo poo it. But if you just want a tiny bit extra, like 50hp it might be an idea to save you shed loads of time and money. Depends what you want to do.

 

I do intend to go nitrous in near future and I will only be 50bhp shot, think may aswell just clean up spare inlet parts and fit and leave inside alone as don't want to do anything to mess up way engine runs and if honest not 100% sure on what's best for inside of inlet parts so may aswell play safe and leave alone