Large port help

Zans

Registered User
Hello, i own an audi s3 apy and would like to increase port size for better airflow. What would be the best option , to convert my small port to large port (by grinding it, machining it, ect...) or buy an AEB head and manifold ? Will the AEB head fit my car ? Is the AEB manifold also going to? Are the valve sizes same for AEB head and my stock APY head?
Thanks a lot!
 

Zans

Registered User
Hi Zans,

Firstly what’s your power goals (BHP) because a small port head is more than fine upto 500BHP.

Ash


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Oh well that's a lot more than i need. I plan on fitting a gt2871r so that would be around 350-380ish hp. I read somewhere that the small port becomes a bottleneck at around 320ish hp
 
Afraid not, this is something I’ve recently found out myself. By using a large port head you’ll loose some low down torque. So unless your planning on going gt30 or larger turbo. I’d use your money elsewhere for the build :)


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<tuffty/>

Badger 5 Edition...Its all about the flow...
Staff member
Moderator
No point in fitting a large port head unless going big turbo...

Typically an non ported large port head will flow more than a ported small port head...

All 20v head castings are interchangable... I ran a ported AEB head on mine... valve sizes are the same, valve train is the same for the most part but have seen differences in valves where the collet grooves are at different heights (assumedly to increase spring preload) and the K04 heads have extra shims where normal 20v head builds don't...

Inlet cams are different between VVT and non VVT heads too

<tuffty/>
 

Zans

Registered User
Afraid not, this is something I’ve recently found out myself. By using a large port head you’ll loose some low down torque. So unless your planning on going gt30 or larger turbo. I’d use your money elsewhere for the build :)


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Okay great!
How About the valve sizes? Will that be affecting any low end power for an increase of +1mm?
 

<tuffty/>

Badger 5 Edition...Its all about the flow...
Staff member
Moderator
Okay great!
How About the valve sizes? Will that be affecting any low end power for an increase of +1mm?
I made 620hp on stock valve sizes.... stick with the small port head, change the exhaust valves to supertech inconel, upgrade the valve springs to cat golds if you really want to

Spend your money elsewhere dude... like on a better turbo than the GT2871r

<tuffty/>
 

Zans

Registered User
I made 620hp on stock valve sizes.... stick with the small port head, change the exhaust valves to supertech inconel, upgrade the valve springs to cat golds if you really want to

Spend your money elsewhere dude... like on a better turbo than the GT2871r

<tuffty/>

Thanks a lot!
 

Zans

Registered User
Exactly as Tuffty says bud....

If I were to go big turbo, I’d be looking into the new G25 range from Garrett. 550 or the 660.

Some fantastic results from the G25-550!


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Thanks a lot for the help!
 

badger5

www.badger5.co.uk
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Oh well that's a lot more than i need. I plan on fitting a gt2871r so that would be around 350-380ish hp. I read somewhere that the small port becomes a bottleneck at around 320ish hp
you read wrong.
stick with smallport
 
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