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Opinions for Porting Factory Manifolds to Support Garrett -9s

TXSquirrel

By TXSquirrel,
in Engines & Forced Induction

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TXSquirrel Community Regular

TXSquirrel

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Opinions for Porting Factory Manifolds to Support Garrett -9s

My engine is out and while it's out, I'm pondering how much to port the factory exhaust manifolds.

I want good responding characteristics and reliability, and I don't care for top end output.  So I get the Garrett -9s and pair them with Tomei Poncam Type A and Tomei dumps.  My factory exhaust ports measured at 38mm x 41mm, and I know OEM N1s are 38mm x 47mm.

I am thinking just 2mm and make them 38mm x 43mm, so it doesn't lag too much at the low end.  I know this is perhaps unnecessary minutia, but I still appreciate your opinions!

infamous_t Veteran

infamous_t

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I would, and I did.... just match the profile of the turbo, no more no less.
Would also recommend if you haven't already, ceramic coating the hotside from manifolds to front pipes while your there.

 

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TXSquirrel Community Regular

TXSquirrel

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14 hours ago, infamous_t said:

I would, and I did.... just match the profile of the turbo, no more no less.
Would also recommend if you haven't already, ceramic coating the hotside from manifolds to front pipes while your there.

 

Are you also running Garrett -9s?  If so, at what psi/bar are you running, and at what rpm does it reach full boost?

No Crust Racing Grand Master

No Crust Racing

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My car cam with Tomei Expreme manifolds, which I removed when I went to -9s and I used N1 manifolds instead as they are cast (so no risk of cracks) and slightly larger than the stock manifolds, but not as big as the Tomei's. Best of both worlds. 

Don't port them for power, port them for response/smooth gas flow. As was said stock manifolds flow plenty for a -9 turbine housing. 

 

 

No Crust Racing Grand Master

No Crust Racing

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Oh and if you want ultimate response get rid of the Tomei cams and get some cam gears only.

 

The best you will achieve with aftermarket off the shelf cams is almost matching response and better top end.

 

The only way you will get better response from a cam is a custom job with mad lift and no extra duration.

 

I have kelford L182A (with -9s, N1 manifolds, big dumps and exhaust and e85) and we basically matched response but with much more mid range and top end grunt.

 

I will also add, and this is an unpopular opinion, if you want response and are going to run the -9s at higher boost, get pods.

 

I gained 14rwkw and response was better moving away from the factory 34 airbox and apexi panel.

 

 

TXSquirrel Community Regular

TXSquirrel

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1 hour ago, ActionDan said:

Oh and if you want ultimate response get rid of the Tomei cams and get some cam gears only.

The best you will achieve with aftermarket off the shelf cams is almost matching response and better top end.

The only way you will get better response from a cam is a custom job with mad lift and no extra duration.

I have kelford L182A (with -9s, N1 manifolds, big dumps and exhaust and e85) and we basically matched response but with much more mid range and top end grunt.

I will also add, and this is an unpopular opinion, if you want response and are going to run the -9s at higher boost, get pods.

I gained 14rwkw and response was better moving away from the factory 34 airbox and apexi panel.

Just intake cam gear or both intake and exhaust cam gears?  And at what degree would you suggest?

Port matching is also being considered, as I'm curious if the exhaust air exits manifold into turbine housing would result in turbulence because of the different size.

Yeah I believe pods would give performance gain across range, but they are just a bit unsightly for me.  I did get the HKS panel filter though, unnecessary expensive for a flat piece of sponge. lol

No Crust Racing Grand Master

No Crust Racing

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Just intake cam gear or both intake and exhaust cam gears?  And at what degree would you suggest?
Port matching is also being considered, as I'm curious if the exhaust air exits manifold into turbine housing would result in turbulence because of the different size.
Yeah I believe pods would give performance gain across range, but they are just a bit unsightly for me.  I did get the HKS panel filter though, unnecessary expensive for a flat piece of sponge. lol


Both gears and get them adjusted on the dyno. Usually it's a few degrees advanced on the intake and a few retarded on the exhaust.

Port matching is fine, just don't open the ports too much.

Get a pod box.
  • 4 weeks later...
TXSquirrel Community Regular

TXSquirrel

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I left the factory manifolds as they are.  But I'm still really struggling if I made the right decision...  

How much of a top end loss should I expect without port matching?  And how much of a lag should I expect if I do?

Engine is still out waiting to get intake plenum back from powder coating, so there is still a chance to reverse course!

bqODxy4.jpg

qc3FjyO.jpg

 

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