Extrude Hone and Flow Bench Tesing

[Boosted Zed]

We have been getting lots of inlet and exhaust manifolds extrusion honed, match ported and doing before and after flow bench tests. The ones of interest for you guys are obviously the RB20-5 and RB26. All testing is performed on a $36,000 flow bench. It is digital and logs results and very accurate. It assimilates what happens in engine although is not an exact as hard to recreate 25 psi or more, although it is a very good indicator and probably the best available in Australia. All tests are performed at 25 inches of water.

The RB26 exhaust manifolds require a bit of match porting and as expected the middle runner is the worst and stock flowed 138.2cfm, after extrusion hone 159.9, then with match porting 167.4cfm. We also got more flow from the outside runners and after honing they are all in better balance as we port and extrude hone the middle ones more. This is quite a gain and less turbulence and restriction by smoothing out coarse casting on inside of manifold and removing the edge of the flanges to stop gases hitting and causing turbulence. Bottom line less heat more flow, more horsepower.

RB20-25 info not handy as we did this a while ago. All I can say is the factory inlet plenum is very ordinary as there is a huge variation from the middle two runners the throttle body aims at and the outer ones. This is why we tune those runners richer with Microtech or Power FC.

[Scooby]

Hi John;

I have been thinking about having my GTR exh manifolds extrude honed and I understand from their Vic agent that impeller ie exhaust side turbo housings benefit also. Appreciate the flow bench results but do you have dyno charts for comparison particularly on a stock motor? Happy to offer my stock car as a test mule if we can come to an agreement on cost. I also have R34 N1s to add to the equation at the same time.

Regards

Scooby

[Boosted Zed]

Obviously to do a proper test it would be changing to extrude honed manifolds only. We know they work from flow bench test and common sense using eyes and feeling it before and after. When you factor in how hard and fast air gets shoved through it then makes sense. My zed is testimony to this technology as it makes huge power especially down low and this is probably part of the reason. 200rwkw at 34000rpm over 400rwkw top end with stock manifolds match ported and extrude honed.

All about thermal management and flow. Engine is like a big pump and if easier to get in and out then less heat and stress and more power. Free power. Also note we have tested some stainless manifolds on other engines compared to factory extrude honed ones and the factory one is better and won't crack, radiate less heat and better to HPC coat as better material to bond to.

[fatz]

yea match porting my stock gtr twin manifolds made a huge diffrence

stock the car ran .75 bar and after the port match it refused to go below .9

spooky

[GTRgeoff]

What's the expected cost for this kind of effort John?

And fatz, I don't even know what choko durries are :confused:

[Boosted Zed]

We just did a big batch and getting some Hightemp black HPC coated and will have them available soon. $540 a pair exchange and probably extra $150 or so high temp black coated.

Details and prices on our site very soon.

[Wazz]

hello i see your signature shows your the manager of UAS.. i was just wondering when the plenum's will be available that are advertised on the site... when i ring all i get is 'wont be to long now.. have got your number to ring you when there ready'

regards

Warrick

[GTRgeoff]

Cheers mate. Mine are custom modified to suit the RB25 so I'll have to get them done myself. Gotta pull the head to find why 1,2,3 are low on compression and 4 has no fuel from injector so might as well optimise the setup. Just running GTR34 BB turbs but dreaming of 2530's...

[fatz]

only jeff at oran park knows what chock durries are

i go the term from him and just use it cause it sounds cool

[GTRgeoff]

Cheers mate, just thought I was being accused of being a massive tool for stuff other than what I already knew about

[Cubes]

Which pots do you tune richer on the RB's? The 3 & 4 or the outer lot?

[R31Nismoid]

RB26, its the rear one i thought.

RB25, i think isnt as bad