2JZ head porting.

[TK]

I've just come out the end of 2 days race porting a set of WRX heads, so I'm in porting mode & while I was eating my pizza just now I read the thread in technical about the 2J build.
Got me thinking I'd really like to have a go at porting one of these things, just to see what they can do, it'd also be a good idea from a business point of view as I don't think too many guys in Aus are porting these things properly yet.

So I've got a proposition for a 2J owner out there:
I am willing to do the R&D for nix & the whole job at minimum cost, I will also supply the gaskets needed to refit at trade cost price.

Job would include:
Strip, clean & bead blast head.
Rectify any issues (corrosion, warping, worn guides etc).
Multi-angle high flow seats.
Porting (Full port, bowls, runners & chambers)
Before & after flow testing + any development flow testing required
CC'ing, before and after in order to return head to original CR after chamber work.
Mill to restore CR
Set up valve clearances, spring installed heights etc
Clean & reassemble with new seals.
Anything else required to have the head ready to bolt back on.

If I water window it (not gonna happen) I'll replace it.

Cost would be under $1250 + gaskets, normal retail on this sort of work would be around $2500, so basically I'll do it for 1/2 price or less in order to get some R&D on these heads.

Engine the head came off would have to be a decent example of the breed, ie: big single + other supporting bolt on's & would have to be dyno'd before (previous dyno run ok) & after to establish improvements.

Progress & results would be posted up here.

Any takers?

TK

[stockymcstock]

if you're interested in doing the same for an RB25 head on a 25/30 let me know

[Rz]

going from the other thread , if you really think theres 1000-1500 rpm sooner spool to be gained then id happily spend the full 2500.
i think that may be slightly optimistic though , just going from what ive seen allready with the 2j.
a couple hundred rpm on the other hand , would still be a excellent gain that would be worth every dollar.

[TK]

WRX's I've done show boost as low as 2300rpm with a 400L turbo on 2.5L (500hp turbo, don't know the other specifics).
One particular engine makes 200rwkw from 2800rpm, peaking at 320rwkw at 6700, torque curve is damn near flat, owner says it dosen't even feel like a turbo engine, it's too linear.
WRX ex ports are terrible tho, so that sort of result may be out of reach, but I'd feel fairly confident I could bring boost on at least 1000rpm earlier & increase top end HP by a fair margin - would be partially dependant on ex manifold.

Only one way to find out, you up for it?

[21OWA]

i would be up for this but my motor is a while off and i wouldnt have b4 and after tests so i guess im out

hopefully the guy doing my headwork will get pretty decent figures as im getting it done for next to nothing

goodluck with it tho, would be good to see the results

[2JZR31]

THIS IS VERY TEMPTING! Not sure if my car is worthy though?

Would this make more power than getting bigger cams? Cost is similar.

[PLAYA]

damn what about a SR20

[TK]

2J - why not?, I know your management system is a wee bit dodgy, ported head may push it over the edge & require a new aftermarket ecu & tuning, but your AF ratios are ok now, so gains would be indicitave of what others could expect - just depends on whether you can afford to run the risk of needing an aftermarket ecu & fresh tune - would add a lot to the cost from your perspective.

Sorry guys, no rb's & no sr's - they've been done, 2J is the jigger that's caught my interest.

I gotta bugger off now, been here since 4.30 this morning to get the rexy heads done on time, I've still got to drop them off, they're getting fitted in about 6 hrs from now.
I'm pretty much rooted, so I'll have to get back here tomorrow.

TK

[PLAYA]

bah the 2 i own, lucky im out of cash!

[Billzilla]

TK - The exhaust ports aren't very good and you can get a lot out of them I reckon. They wouldn't even flow 65% of the inlet I'd guess.
The inlets aren't too tragic, but again would benefit from a tickle up.
I haven't seen the combustion chamber, but I suspect they'll have the usual Toyota cheap & nasty valve surrounds.

[21OWA]

300 cfm on the intakes should be fairly easy, most decent sized multi-valve heads will go there without too much work, matching up the ex flow for big boost is where it gets tricky - you want at least 80% of intake flow, 90-100% would be ideal but probably not doable

just quoted that from my thread
you will be going very well if you can get 80% of the intake flow on the exhaust!
if your flowing 300cfm on the intake, that makes the exhaust 240cfm

theres a guy in the states that put his flow figures up on a head he was selling, not his exact figures but damn close
the head had 1mm oversize valves also but just the std recut seat

he got 306.3cfm on the intake and only 191.5cfm on the exhaust
test was done at 28" of water and 0.450" lift
that makes the exhaust only 62.5% of the intake but he was making 1345rwhp on a DJ dyno with this head!

also might add that HEADGAMES has added a bit of interesting info about the seats
a recut std seat works fine and flows well with 1mm oversize valves but a bigger seat works even better and creats more flow
he then goes on to talk about the "throat"
from there on im lost lol

[2JZR31]

I don't think my car will showcase your talents as well as say, RZ's car, becuase of the limited tuneablilty of my setup and knife edge of grenading it probably already runs on. I will talk to my mate Brad from Boosted Xtremes about it, if he reckons it will be OK with setup I might go ahead. It will no doubt be good for future mods. (someone will no doubt take the offer up first anyway). I will be sticking with 2JZ's for a while since they are such an awesome engine, and could use the head in a more serious car later down the track too.

[2JZR31]

As for flow numbers here they are:


Rb26 (std) Inlet: 148cfm Ex: 105cfm

Rb25 (std) Inlet: 136cfm Ex: 98cfm


2JZ (std) Inlet: 139cfm Ex:121cfm

1JZ (std) Inlet: 134cfm Ex: 115cfm

Seems the JZ's shit all over the RB's in the exhaust and the RB intakes are a little better. These tests were done by the same operator.

[21OWA]

that makes the 2J exhaust 87% of the intake in std form!!

but what figures was the test done at Dennis?

i would be stoked if we get my head to flowing 80%on the exhaust of the intake

[Billzilla]

Seems the JZ's shit all over the RB's in the exhaust and the RB intakes are a little better. These tests were done by the same operator.

Wow, I'm amazed buy those figures. The exhausts really do look pretty sad IRL.