2JZ head porting.

[21OWA]

Nice work TK
my cams have about .45" lift
off the shelf hks are between .35-.4"
i think ill be going 1mm oversize valves also
do you think you could hit 300cfm on the intake with 1mm over valves?
over 200cfm on the exhaust? 70% would be 210cfm

well done again
cheers
Troy

[TK]

do you think you could hit 300cfm on the intake with 1mm over valves?
over 200cfm on the exhaust? 70% would be 210cfm

Yep, on both counts.
Ex valve size is really holding it back - an extra 1mm would make a big difference to the work I could do on the bowls.
An extra 1mm on the inlets would allow me to cut the seats to much more suitable angles & really bump up flow.

The way it has responded on the ex just by optimising the bowl size to the valve shows that there is a lot more potential there.
The big gains on the intake have me a bit confused - for the work done it was completely unexpected, 300cfm should be a dodle with bigger valves.

TK

[Billzilla]

Good work, thanks for the info.

[2JZR31]

Great results TK, and yes it is very common to use one stage bigger cams on the exhaust in both 1JZ and 2JZ engines. Guess you showed why it works.

[Reaper]

TK - you Da' Man! So very impressed with the results as you know from our discussion today.

To put this result into perspective for other readers - Power House Racing (PHR) in the US are well known for building very high power Supra 2J's. They currently sell a CNC ported 2J head inc. 1mm oversize valves, hi speed valve train, bronze guides etc. for $5800 USD retail (non-landed of course) using a brand new (non-core exchange) head.

They have been building hi powered Supras with years of experience (eg. 7/8/9+), and with a machine that costs probably over a million dollars they quote 300/200 cfm IN/OUT at .45" lift.

If you look at TK's figures, and see his results were done on shitty JDM cams/valves (ie. valve lift/diam. = ~.3"/33.5mm IN, ~.34"/29mm OUT) - along with the assertion that fitting 1mm o/size valves WOULD achieve 300/200 cfm with a tad more shaping obviously ...

this basically means Tony will have more or less achieved the PHR result on his first outing! In fact better than that - his very first porting as he has only done 1 of the 6 cylinders.

Currently his .45" figures are 270/180 on stock valvetrain!

What I think is also interesting to note is that if the veterans at PHR and the like cannot achieve a higher IN/OUT ratio this might suggest that getting near a more magical 80% may not be possible. An assumption I know but the PHR's/MVP's/Titan's/BL's/SP's of the world all share proprietary knowledge/services and sell each others shit. If they aren't doing it by now it's a fair bet that it probably can't be done.

As Tony explained to me today - you never sacrifice flow purely to get a higher IN/OUT ratio unless the ratio gets ridiculous. Sure the polluted charge blocks fresh mix getting in and increases the risk of detonation (via residual heat/ dirty charge etc.), thereby requiring a safer tune BUT if the flow comes easily and you are still maintaining a safe ratio then take those gains baby!

The oem ratio was high 60's. At hi lift which is "up where we belong" this is virtually unchanged. Flow gains are significant - basically 20% on both sides at .45 - fucking fantastic! Ratio would be nice but since we have lived safely at such a ratio (and many of us do) then it is not like the ratio has gone backwards - still as safe to live with as it was before except flow is vastly improved.

Now, I think I'll have to go the 1mm valves. TK suggests that a similar improvement to what has already been achieved is on the cards eg. 300/200 +. 24 valves will only cost something like 500AUD (eg. Brian Crower) to land as part of a box of crap leaving shortly, and now is the time before he does the other 5 cylinders.

I know this will throw out the pure "back to backness" of our results but the bench results are already excellent, cams will stay the same for the test, and you'll just have to 'deduct' a fudgey amount for what the valves did on top of the porting if you want to be purist. I guess, however, if someone is going to the expense of all this - 1mm oversize valves could be considered quite a reasonable part of a port job? Logical progression to the wholistic 'flowed head' concept? Regardless I think I'll now go 1mm os.

?? Question for the tech peoples out there who might know - how much lift can you run on the oem 2J pistons?

OK, thanks again Tony - chuffed mate. Will be excellent to see where all this ends up on the dyno and the road. Maybe this 800hp crank snail won't be such a PITA to live with on a 3L after all!?

Cheers mate, catcha soon.

Gaven :D :worship:

PS - forgot to mention - since so much air is being increased it may just be that top end is now ?40+rwkw gain (instead of the previously mentioned 20-30), presumably/definately WITH the bigger valves/additional porting that allows. Big cams will only bring even more flow too - great!

[2JZR31]

You must be rapped man!

[21OWA]

be wary of anything over hks 272 cams with the stock pistons
if you go higher, clay the motor to make sure the valves arnt hitting as over that, the motor becomes an interference motor
ive been told i can run my cams on std pistons but may need to enlarge the releifs a little so the valves dont hit and my cams have over 11mm lift while hks 272 are about 9.3mm

how bout going 1mm oversize on the intake but 2mm oversize on the exhaust?
as far as im aware tho, 2mm oversize valves are a custom order (prob cost more for 12x2mm oversize valves then for 24 1mm oversize!)

as for a set of 1mm oversize valves, i can get them for bout $350AUD + post for the whole set from the states
all up for valves, lock, guides and seals, all ferrea gear, your looking at about $650-$700AUD + post

going by TK's figures, im actually pretty keen to see what a 1mm/2mm setup would flow
i think you could get up around 80% doing this and spool would be improved GREATLY!

[BigMuz]

Good stuff. I reckon just go a mil up on the exhaust valves only, because then the entire internet will discuss the fact that you are one of the only people who understands these heads, and can do better with them for less $. Free advertising FTW.

[TK]

Muz - I thought about just doing exhausts - but it dosn't make sense, the cost of a set of inlet valves is fairly minimal & it looks like the flow will come easy - you never trade flow for a better in/ex ratio, if you can get 80% in/ex with the intake flowing the best you can get it then that's ideal, but an improvement in intake flow will still show more power, even without an ideal ratio.
Having a quick measure it looks like I may have been overzealous saying a 2mm oversize valve will fit - it'd come close, but maybe not quite - a 2mm over ex valve could be used, but you couldn't cut the seat to the edge to get the most out of it so it's kinda pointless.

What Reaper was saying about the CNC heads spun me out a little, but a CNC port job has to be compromised to take into account casting differences between heads - the machine can't adapt for core shift etc. That's why CNC porting will never replace hand porting - it works very well for aftermarket V8 heads with high quality castings but an oem head is never good enough to be able to do a CNC map to get the most out of it + a CNC machine just can't get into the tight spots common in multi-valve heads, not to mention a CNC map has to be taken from a hand finished port to begin with.

Looking forward to seeing what the 1mm over valves will yield, even if it does mean a bit of a delay.

Reaper is also keen to upgrade the cams in the not to distant future, so we'll have results for ported head alone & ported head with cams eventually.

Cams will probably be kelford with 268/272 duration & 9.9mm lift.
Anyone who hasn't checked out the kelford gear probably should - top stuff, I use their cams in a lot of WRX's with very good results - better than HKS etc. In fact they seem to be a little better than megabuck cosworth cams.

TK

[Norbie]

Nice results.

Based on the work you've done so far, can you estimate how much you'd charge to port a 2JZ head in future? I'm thinking about my next step after the GT35R is installed.

[Reaper]

I think I am mate!
Nearing 20% at the prospective aftermarket cam lift levels - woot!

Kudos to TK is all I can say, I thought we may have gotten around 10% so I'm chuffed.

He was showing me some Rex heads that were getting scooped out, and the machine that does the multi-angle valve seats which are later hand blended etc. Looks bloody gorgeous - I know that sounds ghey - but they do!.

You must be rapped man!

[TK]

Norbie - I'll have to wait & see how much extra work is needed with the bigger valves & how long it all takes, I'll work out a price once Reapers head is done - any price given now would be a wild guesstimate.

The rexy heads I'm doing today & tommorrow are monsters, 05 STI castings with solid buckets (no shims to spit), ferrea +1mm valves, performance springs valve springs, kelford cams & a fuckload of porting - they're going on a 2.5 sti bottom end with closed decks, scat rods & forged pistons, some guys have way too much spare cash.

TK

[Reaper]

Don't know mate, I have been speaking to Dusty regularly lately about parts - he is tight with PHR so can ask him if you like. I presume they won't have been dumb enough to test at low vac? I'll ask next time I speak to the man.

reaper do you know how many inches of vac phr is using to quote 300/200 ... doesnt say on their site.

[21OWA]

2jzgte becomes interference with hks 272

you sure about that rusty?
every1 says that they arnt interference but the high lift jun 272 are
the hks 280 are the same lift as the 272 and im pretty sure they say on sf.com that they arnt interference either

either way, just clay the motor if you arnt sure

[21OWA]

Don't know mate, I have been speaking to Dusty regularly lately about parts - he is tight with PHR so can ask him if you like. I presume they won't have been dumb enough to test at low vac? I'll ask next time I speak to the man.

if it was done at 25", that means it will flow more at 28"