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View Full Version : Big port mani to small port head?



Davdraco1
07-20-2014, 06:10 PM
Ive done my research and looked thru a ton of threads, but most of them are old and i'm wondering whats everyone take on this. also, what needs to be done to do the swap correctly.

GrapeBandit
07-20-2014, 06:14 PM
get a transition phenolic spacer

Seerlah
07-20-2014, 06:15 PM
Or just run a small port IM.

BaseDrifter
07-20-2014, 06:16 PM
Isn't your car basically stock? This is one of the lsat things you should be looking at doing...

GrapeBandit
07-20-2014, 06:17 PM
Or just run a small port IM.

this. OP, you can buy my extrude honed small port manifold.

GrapeBandit
07-20-2014, 06:18 PM
http://forums.vwvortex.com/showthread.php?6041885-FS-extrude-honed-intake-mani

Seerlah
07-20-2014, 06:32 PM
^Just did the math and that is roughly an 18% flow increase over stock. Not too shabby. Was really considering grabbing it off you, but I need more volume (plenum) too. But I have a bigger turbo. Your manifold would be perfect for up to maybe the 350chp range or so (taking a guess here). Not saying a larger plenum unit would not be best, but weighing cost of item vs gains it makes more sense (ie 5-10hp gain on less flowing setup vs like a 50+hp on a different).

GrapeBandit
07-20-2014, 06:37 PM
^Just did the math and that is roughly an 18% flow increase over stock. Not too shabby. Was really considering grabbing it off you, but I need more volume (plenum) too. But I have a bigger turbo. Your manifold would be perfect for up to maybe the 350chp range or so (taking a guess here). Not saying a larger plenum unit would not be best, but weighing cost of item vs gains it makes more sense (ie 5-10hp gain on less flowing setup vs like a 50+hp on a different).

well if you were to ever consider it, im negotiable on the price. I have aeb now and cant use it. so its just an expensive paper weight to me non

Seerlah
07-20-2014, 06:38 PM
PM me the lowest you will go. I can pick it up from you when you are in NJ, so no shipping.

Davdraco1
07-20-2014, 07:50 PM
Grape, can you describe what you did to the mani? In assuming making the ports larger, and I picked up a used big port IM at waterfest. I've read that the injector seats are different and the rails won't line up or something...? Need some info please! Thank you everyone.

GrapeBandit
07-20-2014, 08:05 PM
this is what was done.
http://boneheadperformance.com/extrude-honing/
but the part is basically sold as soon as I dig it out tomorrow

Davdraco1
07-20-2014, 08:16 PM
I'm going to try to polish and port match it to the spacer/adapter the best I can.

Seerlah
07-20-2014, 08:21 PM
Just slap the 034 spacer in and go. I am running one myself, except for the cooling effect (straight small port).

GrapeBandit
07-20-2014, 08:22 PM
I'm going to try to polish and port match it to the spacer/adapter the best I can.

what spacer/adapter?

Seerlah
07-20-2014, 08:26 PM
http://store.034motorsport.com/intake-manifold-spacer-1-8t-phenolic.html

GrapeBandit
07-20-2014, 08:28 PM
http://store.034motorsport.com/intake-manifold-spacer-1-8t-phenolic.html

exactly what I suggested to OP earlier. thats really his best bet if hes trying to run aeb intake mani on awm head

Seerlah
07-20-2014, 08:36 PM
Only other option I see is him tapering (gasket matching) the head itself with a shop vac to catch debris.

GrapeBandit
07-20-2014, 08:47 PM
Only other option I see is him tapering (gasket matching) the head itself with a shop vac to catch debris.

yea, but thats a lot of work for someone who isnt experienced. the ports are a big difference in size...lol...it can turn sloppy real quick. if OP doesnt have experience and or the tools to do this, it would be more economically feasible and safer to get the transition phenolic spacer.http://img.photobucket.com/albums/v239/ghost6303/ports.jpg

Davdraco1
07-20-2014, 09:15 PM
So I think it's safe to say I will need the spacer. That will go on my list. I've ready the injector seat are different on the aeb IM compared to my current AWM IM. I've looked at my injectors and I think cylinder 2 or 3 injector is leaking. I know the seats are plastic and crack over time. I want to eventually go with a gt28 elim kit with 440cc injectors. (Uni BT Tune calls for the "green giants") can I install the 440 injectors and run them on a stock tune until do the kit? Will they make a difference? Also, I've read the awm fuel rail won't work with the aeb IM? What are my options?

Seerlah
07-20-2014, 09:37 PM
1) Research stuff
2) No, you can't run 440cc injectors with stock tune on stock turbo unless you want to run pig rich with a constant CEL.
3) They have billet injector seats out there if you have the money (http://www.verdictmotorsports.com/Volkswagen_VW_Audi_Injector_Cup_Billet_1_8T_20v_p/vms107.htm)
4) Source an AEB fuel rail and swap it in. Or get a high flow one. (taking a guess, but options I would have given myself. think the only difference would be height after being bolted down and would be at a slight angle. once again, taking a guess)

rodgertherabit
07-21-2014, 06:44 AM
^This.

You need 3 main things.

1. Transition Spacer
2. Injector Spacers (USRT and IE make/sell them)
3. AEB Fuel Rail

GrapeBandit
07-21-2014, 06:55 AM
I may have aeb fuel rail if you want to buy it. I have to check my parts bin first.

Davdraco1
07-21-2014, 06:57 AM
Pm if you do with a price. Also, the transition spacer from the mani to the head right?

GrapeBandit
07-21-2014, 07:16 AM
Pm if you do with a price. Also, the transition spacer from the mani to the head right?

ill look for it in a few hours.

yes, the phenolic transition spacer that goes in between the intake mani and the head. just so you know, its not just to adapt big port mani to small port head or vise versa, it keeps IAT's down and it stops heat soak from your head going into the intake mani

Davdraco1
07-21-2014, 07:19 AM
Yea, I looking into them a while back. Not a bad investment. Id say it's a 50/50 with people being sceptical about them, but if I wanna do this I kinda need it. Lol. So what injectors should I run that will work with my tune?

SquishyPanda
07-21-2014, 07:33 AM
Would the larger intake runners do any good if airflow is bottlenecked into the smaller ports anyway?

(Not trying to discourage OP, just curious if this is something worth looking into myself.)

GrapeBandit
07-21-2014, 07:54 AM
Would the larger intake runners do any good if airflow is bottlenecked into the smaller ports anyway?

(Not trying to discourage OP, just curious if this is something worth looking into myself.)

sure, why wouldnt it benefit? its like throwing on an upgraded intake manifold, sort of

rodgertherabit
07-21-2014, 08:14 AM
THe largeport has been dyno proven to be bolt on 10-20whp over a stock smallport on a Transverse 1.8t on another forum

Due to the shape of the longitudinal manifold, I would suspect flow would be even better. I have a mani, spacer, and polished fuel rait, just ordering some spacers this week actually. Maybe even a TB adapter.

Davdraco1
07-21-2014, 08:16 AM
I've read that the increase in volume of the IM will decrease the velocity of the air going into the head..... All I know is I've never seen a chevy 350 with a smaller IM gain ho..... Jut saying.

demonmk2
07-21-2014, 09:46 AM
I would imagine NA and forced induction work differently.

Davdraco1
07-21-2014, 10:04 AM
Okay, how big are the piping on high hp cars? It's not no 1.5in diameter...

SquishyPanda
07-21-2014, 11:48 AM
sure, why wouldnt it benefit? its like throwing on an upgraded intake manifold, sort of

I would have thought any increased flow would have been negated once the air hits the smaller ports in the head, plus the turbulence of hitting a sudden transition, even with a transition spacer. But then maybe it's a different story with a turbo pushing things along. I'll keep an eye out for an AEB next time I'm at the junkyard and try it out if it's relatively inexpensive.

melomandn
07-21-2014, 01:14 PM
THe largeport has been dyno proven to be bolt on 10-20whp over a stock smallport on a Transverse 1.8t on another forum

Due to the shape of the longitudinal manifold, I would suspect flow would be even better. I have a mani, spacer, and polished fuel rait, just ordering some spacers this week actually. Maybe even a TB adapter.

Its been proven in the b6 section that the AEB largeport does not show substantial increases in power until the car is over 380awhp

Davdraco1
07-21-2014, 01:56 PM
I was thinking that the velocity would actually increase. This if it like a garden hose, it is pressurized, like out cars are bc of boost, then when you make the hole smaller at the end of the hose with your Thurman or whatever, the pressure increases. Now in this case it would be more volume of air and higher pressure, bc of the big mani and small head. Idk, let me know what you guys think on that.

GrapeBandit
07-21-2014, 02:04 PM
awm and all small port heads have a higher velocity than all aeb heads, but aeb heads flow more.

putting aeb manifold on awm head can only help, it cant hurt

Davdraco1
07-21-2014, 02:32 PM
That's how I'm looking at it, if, and it's a big if, it does decrease performance, how bad would it really be????? Plus, I will get some knowledge on the parts and the install. Oh, idk of it's been answered, what injectors, or seats can I use? I want the 440 green giants some day, bc the uni BT tune calls for them and I like the reviews on them. What else will I need? I know there's no mounting for the two valves underneath the mani. The n249 and the other that I can't think of. How would I rig them up?

Seerlah
07-21-2014, 04:50 PM
Having more flow def helps. What was proven was not the manifold adding gains, but an AEB cylinder head making you add nothing but extra spool time on bigger HP applications. People always assumed that more is better, but not always. It is if you have ample air flow (substantial). But not when you do something like a GT28 series (or similar) and smaller.

OP, I see you gaining absolutely nothing from your larger intake manifold with the stock turbo. Someone had to say it. I would suspect a decrease in performance actually. But that has yet to be proved (I'm sure it has been confirmed or debunked elsewhere). Person who said they seen a 20whp gain from swapping manifolds could not have been referring to a stock turbo setup. That is just too much of a gain without a larger turbocharger.

Davdraco1
07-22-2014, 10:19 AM
Well I want a BT some day so I guess I will hold into it until then....

Seerlah
07-22-2014, 03:51 PM
Great choice. The stock intake is a def bottle neck when it comes to BT, just like the exhaust. You want ample air flow in, and exhaust flow out.

Davdraco1
07-22-2014, 05:17 PM
The exhaust is currently gutted cat with a full 3in cat back from cx racing. I don't wanna say it's straight pipe..... But I look fight thru the resonator and muffler....