Turbo Power Porting

[robbo33]

Anybody know much about this so called "power porting" of turbo comp covers.

Has anyone had their comp cover power ported??

More info at the link below

http://autospeed.drive.com.au/cms/A_0622/article.html

Edited August 9, 2007 by robbo33

[DjeMz]

3 threads?

[Adriano]

I wouldnt go crazy on the comp housing, but on the exhaust i would do some hand reprofiling to better integrate the wastegate and then power porting, but it depends completely on the turbo.

[MANWHORE]

When I have time, i always use a die grinder and smooth out the flow path inside thte housings. The exhaust housining is the main one that needs it. You'll notice all these random casting dags inside and obstructions everywhere.

You can go as far as port matching everything - manifolds etc.

Using extrusion honing takes it to the next level, but I have noticed really good gains doing it by hand with a die grinder.

[dead32]

when you say *gains* what are you refering to? power? response? driveability? etc.. cheers

[Adriano]

By far the best gains ive had is from boost control, however thats usually why im porting them to fix a problem, not on nissan turbos though, what turbo do you have? I believe the nissan ones dont really need it

[Cubes]

I recently port matched my Gt30 .82 IW.

Origionally it was absolutely shocking. ~5mm overhang each side of the flange. I would hate to imagine what that would do to the exhaust gas flowing out of the exh. manifold and smack in to it.

While I was there it took 5mins to port match the exhaust manifold; the turbine housing took a good few hours to get it all good.

I have a carbide bur and found it easier to port match with a few packs of supercrap grinding stones on the end of a drill.. The exh manifold and turbine housing are both quite soft metal and comes off smoothly without much effort when using the grinding stones.

The carbide bur results in a messy 'looking' port; I found it difficult not to have a wavey affect using the carbide bur as it takes off so much metal too easily.

The head to exh. manifold port match was terrible; the t3 outlet on the exh manifold was pretty close to spot on.

I wasn't able to get in and smooth out the flow to the wastegate but it did feel fairly smooth. The leading edge could have definitely had a bit of meat taken out to aid flow in to the wastegate.

Here's the pic.

http://www.skylinesaustralia.com/forums/in...t&id=107723

As for powerporting the blokes over on calaisturbo.com have been doing this with great results. I'll consider it at a later date to chase up to another 30-40hp.

Running super rich with conservative ignition I've seen 6000rpm in third with no knock and boost held nicely on 14pounds. So the std flap appears to be holding boost quite well.

[MANWHORE]

Through port matching, and general cleanup of the housings/manifolds/exhaust (manually), I've noticed more power and response. The results have been visible on the dyno.

Yes, I hear you say dyno test was done on different days, but after doing a number of tests, you get a idea of the general range the results are. After the grinding, the results were a fair bit higher.

With a stock car, doing this mgiht not yield much results. But when you hvae a car pumping out 22-24 psi on a gcg highflow, you can imagine it making a fair whack of difference.

[Cubes]

There HAS to be gains port matching that horrid T3 turbo flange that garrett supply. Why they would not stick to standard flange sizes beats me. :S

[robbo33]

ive just purchased a hks gt-rs kit, so im assuming they are pretty good straight out of the box.

However i have a mate that got it done on his garrett gt3071r in his datson 1600 with fj20 and got 24rwkw extra on the same boost. This was at 20psi so like you said MANWHORE at this level of boost there would be gains. im only looking at 240rwkw on my r34 gtt neo with about 15-16psi so probably wont notice it

[Cubes]

Michael,

What did he have power ported? Turbine and or Compressor covers?

I'd expect the HKS turbine inlets to be port matched to T3 standard specs from factory. Throw a gasket up against it and let us know how they fare.

[sweetr33]

i just purchased a garret gt35/40 .82 ex so i'll be looking at the housing when it arrives, now its been brought to my attention about benifits of matching manifold and fplange i'llbe spending MORE time on it now i think haha

[discopotato03]

Hi Cubes , it may be interesting to have a look at some of Garretts data on T3 flanges and port dimensions . You may find that the Nissan "T3" flanged exhaust manifold is actually split or twin entry T3 flange size . I think its logical that split T3 flange ports would be slightly wider because the divider takes up some space .

Cheers A .

[Cubes]

Interesting to note Disco.

The hole wasn't central on the flange either. Thats what led me to believe something was a little fishy. :S

Another thing thats interesting is the T3 inlet of the std turbo was the same size as genuine and aftermarket gaskets.

[discopotato03]

I wasn't actually looking for this pick , it kind of found me ?

[sweetr33]

so ^^^^^^^^^^^^^ whats the verdict with that>:

[Bass Junky]

I'd be keen on getting this sort of stuff done.

Extrude honing everything would be a very interesting project.

Exhaust manifold especially.

[MANWHORE]

Bass, extrude honing is one thing. I think of it more like a final get the last little bit extra.

Port matching is the main thing you'd want to be looking at. Port matching woujld me measuring up the turbo and how it mates with the manifold, how the turbo mates with the dump, how the dump mates with the front pipe etc etc you get the idea.

Then, you take to it with a die grinder to match the ports. While you're at it, you can also clean out any casting dags/uneven surfaces that you can reach with the grinder.

This has huge gains compared with the extrusion honing. I'd the the extrusion honing after I do the port matching. Extrude honing will take care of that tiny bit extra that your'e lookign for after

[Cubes]

There was a thread a little while back where Sly33?? had his exh. std. manifold extrude honed. Flow was picked up and evened quite a bit. BUT if it shows as real world resuts has yet to be seen.

When extrude honing first they port match and then they begin playing with the goo.

Being port matchedinitially 'possibly' may reduce the cost of extrude process a touch.

UAS do extrude honing.

[sweetr33]

if the die grinder needs to be used on ex housing, is it necassary to take it off turbo before grinding??