# OBX large port intake manifold pictures/info



## Doooglasss (Aug 28, 2009)

Went out on a limb and purchased the OBX intake manifold for $400 shipped off eBay. They make a small port model as well. I know there was a post here awhile back so I wanted to share the in person results *(aka my uneducated opinions)*.

It looks like it's an RMR intake knockoff (at half the price) which did well in the intake manifold test awhile back.

Intake manifold test

Ross Machine Racing Website

First off a lifetime warranty card popped out of the packaging. That's got to be a nice feature.

As far as the craftsmanship goes- the flanges all appear to be straight and the welds don't look bad- again this is by appearance. The intake manifold ports measure at 54mmx26mm and the TB entrances measure in at 70mm. The adapter plates provided are for a 70mm TB & 80MM TB - the 80mm is tapered. The stock 60mm TB will bolt right on to the manifold, however, there is one small issue with this. The outer bolts by the rounded part of the D plenum are too close to the welds. I was able to crank the bolts in there but washers should be used on the hardware in retrospect. Also a nice feature is that the TB and the accessory plate are swappable to either side.

You can see where welded parts don't line up perfectly in the runners - there are two visible joints. Inside the plenum has similar results with the runner entrances. Somebody who cared more than me could sand these down I'm sure.

The provided fuel rail is adjustable in height and I had no problem tightening down my new injectors into it. It appears that the fuel injectors don't protrude into the flow of the runners which I'm sure is helpful. 

Won't be able to install it on the car for a little bit, but just wanted to share the info thus far. Opinions are always welcomed.


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## warranty225cpe (Dec 3, 2008)

Damn Doug, that looks pretty nice. I like the ends with the vac ports. Think there would be any advantage to running one on a ko4?


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## 01ttgt28 (Jun 23, 2009)

lol I was going to buy one but the pics on eBay sucked.if they had a bunch of pics like the ones you have I would of got one they look pretty nice :thumbup:


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## 1fast2liter (Apr 4, 2005)

i cant say for a tt but similar style manifolds for neons and srt4 showed about a 20 hp gain over a stock manifold... on a couple of engines were big turbo and 20 psi was used the swapping of the manifold showed a 30whp gain.. but they also went to a large tb also at the same time....


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## mbaron (Aug 21, 2008)

Looks like a nice piece for $400. I hope the install goes well for you.


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## Doooglasss (Aug 28, 2009)

Thanks guys- not sure of their advantage on a K04. I remember seeing smaller gains with other large plenum intakes on K04s.

I've heard larger TB's are difficult to control with BT tunes so I've been staying away from them. Down the road I'll probably try one again though. On my last tune I had a 70mm and it was terrible.


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## Atomic Ed (Mar 19, 2009)

It does look better than I thought it would. Could you pop an end off and get a shot of the inside?


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## Krissrock (Sep 10, 2005)

gains will be minimal if any without the larger head. Gains become very significant wit a big turbo, big port head and throttle body...

but definitely looks like it was worth the money.


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## PLAYED TT (Oct 17, 2010)

Nice find Doug. Your that much closer to finishing! I'm excited for you:thumbup:


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## bvgoosedd (Mar 5, 2009)

I dont know if iam stupid but can u explain what u mean? About using the stock tb and it bolting up to close. Iam guessing because there is no plate being used? Can u post a pic of what u mean. Thanks


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## Doooglasss (Aug 28, 2009)

I'll take more photos this coming week. If my back gets better I'll be doing a lot of work.


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## 20v master (May 7, 2009)

Krissrock said:


> gains will be minimal if any without the larger head.


Not true (but depends on your definition of "minimal." Max has mentioned the concept of negative boost, and it's an old term from an Autospeed article back in the early 2000's. Any removal of a drop in pressure allows your compressor to run more efficiently, thereby lowering intake charge temps, which means denser air and less chance for detonation so you can run more ignition timing advance, aka good things.


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## madmax199 (Oct 28, 2009)

20v master said:


> Not true (but depends on your definition of "minimal." Max has mentioned the concept of negative boost, and it's an old term from an Autospeed article back in the early 2000's. Any removal of a drop in pressure allows your compressor to run more efficiently, thereby lowering intake charge temps, which means denser air and less chance for detonation so you can run more ignition timing advance, aka good things.


Very true, I've read many times on various 1.8t forums that there's minimal gains from a better flowing intake manifold on OEM turbos. What's missing IMO is at what pressure you don't gain much from an IM? The way a turbocharged engine works seems to indicate the opposite of what is common knowledge around here - remove any flow restrictions that create "pressure loss" like Adam mentioned and it will result in better efficiency out of the turbo/engine combo. You may have to adjust fuel and timing to fully take advantage of that re-gained boost but regardless the system is more efficient. 

I think that the reason you find tests that reveal marginal gains is because they are all conducted at pressure where the intake manifold is not the big restriction point. If other stuff downstream of the manifold is chocking already (SMICs, OEM crushed pressure sensor pipe etc) you'd need to increase pressure and velocity considerably to fully see the effect of a better flowing IM. At 20 psi, the OEM manifold is likely to be efficient enough but raise that pressure to 25+ psi and you will see nice gains from an improved IM. The same also goes for the other restrictive pieces on the intake side like the SMIC, turbo outlet resonator pipe, pancake pressure sensor pipe etc. 

BTW, the exhaust side is even worse! However, to remain on the intake side, since this is about IM, I have recorded an average of 5 psi of pressure loss before the manifold (I say average because I had no way to record steady state when I did my experiment). I hooked up a boost gauge at the turbo outlet and recorded the pressure differential between there and the manifold, the result was an eye opener. The reason I'm saying all this, is because with all those restrictions out of the way, there is much to be gained from an IM, even on OEM turbo :beer:

I've been looking into upgrading the IM in my car just like Doug but the high price or questionable designs have kept me from doing it yet. I want SEM but can't justify the price tag, maybe this new IM that Doug is testing will prove efficient enough to get my business ( a slightly smaller plenum and raised velocity stacks would make a great DIY intake manifold too, so we'll see).


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## 1fast2liter (Apr 4, 2005)

well said... its all about moving pressure from one side to the other and doing it as fast as possible the less restrictions the better it is.. another way to think is a straight hos vs a kinked twisted hose the stright one will flow better the the kinked one.... open up the im the head and diff turbo you ot the exhaust mani left and i know right their is a huge restriction


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## speed51133! (Aug 5, 2002)

Is it in fact large port? I remember that manifold being advertised on ebay as large and small port available but really only small and they said it will bolt to either. This was like a year ago.


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## Doooglasss (Aug 28, 2009)

Yep it's a large port intake manifold- the port measurements are identical to my AEB head. They also make it in small port but with products like the 034 transition spacer I'm not sure why anyone would but a small port. 


---
I am here: http://maps.google.com/maps?ll=40.705473,-74.008600


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## 20v master (May 7, 2009)

madmax199 said:


> I want SEM but can't justify the price tag


There's not a better one out there, and the offer I gave to you still stands.


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## madmax199 (Oct 28, 2009)

20v master said:


> There's not a better one out there, and the offer I gave to you still stands.


It's good to know it's still there, I've since decided to stay with driver's side facing TB and go air to water IC as you originally suggested. I will contact you on the SEM :thumbup:.


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## vwgtiawp (Jun 1, 2009)

Would it be better to get the large port vs small on an AWP motor? with a big turbo and built bottom end.

Also what type of fuel injectors could I use?


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## 20v master (May 7, 2009)

Depends on how big your big turbo is. AWP is small port, so gains won't be fully realized by going to a big port mani without the matching head port size.


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## vwgtiawp (Jun 1, 2009)

might go with the SEM manifold for reliability. no one seems to give the OBX unit a thumbs up for reliability. Im making a 400 hp daily driver 8-10k miles a year...

making = puting together...


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## 20v master (May 7, 2009)

What turbo though and at what boost level?


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## vwgtiawp (Jun 1, 2009)

20v master 
What turbo though and at what boost level? 

gt35 style Garret 22-25 lbs. Just want to be over 400 whp


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## 20v master (May 7, 2009)

On pump gas? What compression ratio?


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## vwgtiawp (Jun 1, 2009)

9.5 on pump if possable


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## vwgtiawp (Jun 1, 2009)

thats why i was thinking to do a manifold. to make the power easier. I figured 400 on pump might be hard.


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## 20v master (May 7, 2009)

The manifold will definitely help make the number at lower boost levels. I made 415 FWHP on a 3076R @ 22 psi but it was an AEB head, stock pistons/comp ratio/bore on pump gas.


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## Arnolds64 (Nov 13, 2009)

*The Chinese are getting good!*

I bought the SS Chrome headers, Stainless ( Chinese made off Ebay) for my old MX6 LS that I gave to my son and they are now 6 years old and do not leak. They are getting just a small amount of rust on them. China now has had plenty of time to get better at making "American Made" stuff now. 
So if you think Romney or any of these other bastards are going to bring back middle income jobs you are smoking a huge doobey. Our time as the strongest economy is over. Get use to 4 cylinder Turbo cars and Hybrid electrics being the only things we will have in the future thanks to all our great leaders allowing all this to happen. I loved the V8 torque belching nasty sucking gas, polluting beautiful sounding machines of old. Nothing like them!


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## Doooglasss (Aug 28, 2009)

I'd estimate I'm making about 400whp at ~20 psi right now daily driven with this manifold on the car. Been driving for a few thousand miles like this and already took advantage of the ability to swap the TB from side to side while redesigning my FMIC piping.

400whp on pump isn't hard. I made 410fwhp @ 24psi last year with a small port head and stock 225 intake manifold.

The real test will be when this thing see's 30+ psi and if it blows or not...

Note on Chinese building: EVERYTHING is made in China. Final assembly or machining happens in the USA. Lots of respected, big name vendors on here use parts straight from China.


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## vwgtiawp (Jun 1, 2009)

everything electronic is from asia. I sell VW's and the back up cameras are not on the vehicles beacause of production has slowed because of the disaster. Just now getting back up cams on the CC's.


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## vwgtiawp (Jun 1, 2009)

what kind and size and kind of injectors did you use to make that 400whp? same as on the stock mani?


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## 20v master (May 7, 2009)

630's are plenty for that power level on gasoline.


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## Doooglasss (Aug 28, 2009)

I originally had 870's last year. Now have ID1000's which are apparently really 900cc...

You can pull it off with 630's though. You'll probably get a better off the shelf tune for em too.


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## seth_3515 (Dec 26, 2008)

Has anyone pushed these past 22-24psi consistently? I got an SEM, but im just curious to see if there is another option for other enthusiasts out there.


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## Doooglasss (Aug 28, 2009)

seth_3515 said:


> Has anyone pushed these past 22-24psi consistently? I got an SEM, but im just curious to see if there is another option for other enthusiasts out there.


I had lots of PM's asking the same question about the pressure this can hold. I'm up to 30psi now for the past week with no problems at all.

Plan on getting to 35 if my injectors allow it.


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## 01ttgt28 (Jun 23, 2009)

DougLoBue said:


> I had lots of PM's asking the same question about the pressure this can hold. I'm up to 30psi now for the past week with no problems at all.
> 
> Plan on getting to 35 if my injectors allow it.


Have u tried to dyno the car yet


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## Doooglasss (Aug 28, 2009)

01ttgt28 said:


> Have u tried to dyno the car yet


Just signed up for a dyno day in NJ for an AWD dyno in late April.

The 02 correction at 30psi is way too high- I just finished installing a MAF last night to try and remedy that but sadly didn't have time to do testing. If I can get the correction and lambda in line I'll crank it up to 35 and see what my injector duty cycle is at. After that Max has to add massive amounts of timing and then we hit the local FWD dyno. 

I bet around 500+ FWD at 30psi.


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## 01ttgt28 (Jun 23, 2009)

DougLoBue said:


> Just signed up for a dyno day in NJ for an AWD dyno in late April.
> 
> The 02 correction at 30psi is way too high- I just finished installing a MAF last night to try and remedy that but sadly didn't have time to do testing. If I can get the correction and lambda in line I'll crank it up to 35 and see what my injector duty cycle is at. After that Max has to add massive amounts of timing and then we hit the local FWD dyno.
> 
> I bet around 500+ FWD at 30psi.


I what to see a video no excuses


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## Tempes_TT (Oct 24, 2010)

01ttgt28 said:


> I what to see a video no excuses


this! :laugh:


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## Chuckmeister87 (Nov 10, 2009)

You guy's are running big numbers under your hoods! Good god! 


I seem to be reading the arguments wrong on the first page.. someone says a bigger IM wont do much for a stock engine and turbo, then someone else says it helps a lot. Which is it?


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## TheDeckMan (Sep 26, 2004)

Chuckmeister87 said:


> You guy's are running big numbers under your hoods! Good god!
> 
> 
> I seem to be reading the arguments wrong on the first page.. someone says a bigger IM wont do much for a stock engine and turbo, then someone else says it helps a lot. Which is it?



Helps a lot, providing that your balancing out the intake and exhaust sides of the engine. Its all about reducing restrictions. 

More psi does not always = more power. More air + More fuel = More Power!

A 1.8t small port only flows in the 140-150cfm range at 18 vac, if my memory from the flow bench serves me right. 

Larger intake manifold volume allows for more air to be available on request and allows a lower loss in CFM flow. But you need the exhaust and further upstream on the intake side to also be matched to the intended flow. 

For example, on a supercharged VR6 with 12psi a 25% increase in down pipe size and a test pipe nets 30+whp. 

As you can see, you do a well designed intake manifold with the 42DD intake, Forge inlet and a matched intercooler setup you will maximize your intake side and allow you to take full advantage of a down-pipe and exhaust.


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## 1fast2liter (Apr 4, 2005)

Were all 2000s small port? I really like this im

Miss spelled words courtesy Motorola electrify via tapatalk


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## Chuckmeister87 (Nov 10, 2009)

DeckManDubs said:


> Helps a lot, providing that your balancing out the intake and exhaust sides of the engine. Its all about reducing restrictions.
> 
> More psi does not always = more power. More air + More fuel = More Power!
> 
> ...



Haha, it makes sense. I was going to do my intake an exhaust same time (if I ever got the money for it) to maximize airflow and power. I figured if I gave more room for exhaust, but my engine couldn't push anymore air through because of the stock intake, then why get exhaust?

Likewise I thought if I can allow a lot of air into my engine, but it can't get it all out through my stock exhaust, then why waste lots of money on just intake? I decided I needed to do both at the same time to keep everything even, just as the good mechanics had intended. :laugh:

Ty for the info :thumbup:


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## TheDeckMan (Sep 26, 2004)

1fast2liter said:


> Were all 2000s small port? I really like this im
> 
> Miss spelled words courtesy Motorola electrify via tapatalk



All TT's are small ports. Large ports were found on 1996-1999 B5 A4's. Doug has swapped to a large port I believe.


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## vwgtiawp (Jun 1, 2009)

I have to make up my mind in the next 2 weeks on the manifold. I am leaning towards getting it. If there are any other with updates good or bad on this manifold?:thumbup:


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## 1fast2liter (Apr 4, 2005)

DeckManDubs said:


> All TT's are small ports. Large ports were found on 1996-1999 B5 A4's. Doug has swapped to a large port I believe.


Not doughting you but i thought the newer 02 ups were large port?...

Miss spelled words courtesy Motorola electrify via tapatalk


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## 20psi now (Feb 26, 2009)

1fast2liter said:


> Not doughting you but i thought the newer 02 ups were large port?...
> 
> Miss spelled words courtesy Motorola electrify via tapatalk


ALL TT's are small port... AEB is the only (state side) head that I know of that come large port. :beer:


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## l88m22vette (Mar 2, 2006)

Yea, like this? (warning, internet whoring imminent)


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## Doooglasss (Aug 28, 2009)

l88m22vette said:


> Yea, like this? (warning, internet whoring imminent)


Be sure to swap VVT in there now and not later like I'm doing. I replaced my chain tensioner with non-vvt when the head was off the car. Now bought a VVT tensioner to replace that with but the job will be much more of a pain in the ass!


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## Vdub 2.0 (Jan 8, 2008)

DeckManDubs said:


> Helps a lot, providing that your balancing out the intake and exhaust sides of the engine. Its all about reducing restrictions.
> 
> More psi does not always = more power. More air + More fuel = More Power!


 If you are trying to equal out both sides what about the stock 225 exhaust manifold? It has been proven to be even less efficient then the 180...:screwy:


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## TheDeckMan (Sep 26, 2004)

Vdub 2.0 said:


> If you are trying to equal out both sides what about the stock 225 exhaust manifold? It has been proven to be even less efficient then the 180...:screwy:


The design of the K04 manifold is very restrictive. However you can extrudahone the manifold to increase the velocity of the exhaust gases. It is expensive, but the best route. 

The K03 manifolds are more simple and you can get a high flow one that nets you a 10hp gain. However, the high flow manifold is a PITA to put on/take off. 

Most ideal setup would be

42DD intake
Forge Inlet
Tryol SMIC's
SEM Intake manifold (large port)
AEB head (large port)
Extrudahoned turbo manifold (ceramic coated)
F23 Turbo
42DD 3" Turbo back exhaust
IE Rods

(2.0l for lots of torque)

This would be one monster setup dialed in on E85 or C16, minimal lag and lots of power.


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## l88m22vette (Mar 2, 2006)

That setup would be mint with a GTX3071, the whole k04 turbo setup is the restriction at that point. You'll get massive heat build-up, it'll be choked, and you will want to change it within a year. Doug's 1.8 AEB/SEM Frankenturbo is the limit for this approach - more engine flow, upgraded ex. manifold, "k04" turbo, but still well-rounded. The stroker and alt fuel is like 5 steps past the k04, and the SMICs won't ultimately beat a FMIC. Also, you need pistons and a crank for a stroker, not just rods. Rods ~$450, stroker ~$1300. 



DougLoBue said:


> Be sure to swap VVT in there now and not later like I'm doing. I replaced my chain tensioner with non-vvt when the head was off the car. Now bought a VVT tensioner to replace that with but the job will be much more of a pain in the ass!


Yep, planning to, I'm glad I saved on the head, its ridiculous how much the VVT tensioner is ($500, really? :banghead Did Tobz ever talk about the metal plunger, or whatever, to replace the plastic one which wears out quickly? I wouldn't want to put one in until I find out if that issue is solved, no reason to spend for a VVT and get non-VVT within 20k.


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## Doooglasss (Aug 28, 2009)

I got a VVT tensioner for $100 brand 
New. I'll have to send or post the website later. It's sitting on my desk in NY now but sadly I'm sitting in PA....


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## 01ttgt28 (Jun 23, 2009)

DougLoBue said:


> I got a VVT tensioner for $100 brand
> New. I'll have to send or post the website later. It's sitting on my desk in NY now but sadly I'm sitting in PA....


wish i known i got 2


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## warranty225cpe (Dec 3, 2008)

So if I buy an AEB head for my BEA (VVT equipped) is it going to be a pain in the ass the do?


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## 20psi now (Feb 26, 2009)

warranty225cpe said:


> So if I buy an AEB head for my BEA (VVT equipped) is it going to be a pain in the ass the do?


I thought thay swap over, as for VVT and NON VVT they will bold in. The BEA block is the same as any other, so heads suold just swap.


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## 20v master (May 7, 2009)

warranty225cpe said:


> So if I buy an AEB head for my BEA (VVT equipped) is it going to be a pain in the ass the do?


It's a German product, yes it'll be a pita. :laugh:


Seriously, if you have the right tools, it's not bad.


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## l88m22vette (Mar 2, 2006)

Yep, its simply swapping everything from one core to the other (cams, chain, tensioner, etc). Keep the AEB cam caps, bolts, and other attachment stuff. You could also get the ARP head stubs, the AEB and the 06A block had different head bolt sizes, PM Harry Sax if you'd like details (or Doug should know too)


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## clarksongli (Nov 4, 2003)

l88m22vette said:


> Yep, its simply swapping everything from one core to the other (cams, chain, tensioner, etc). Keep the AEB cam caps, bolts, and other attachment stuff. You could also get the ARP head stubs, the AEB and the 06A block had different head bolt sizes, PM Harry Sax if you'd like details (or Doug should know too)


Honestly, unless you're shooting for a dyno monster, why bother with all of this?

I will be the first to admit.....i only have AEB big port heads in my cars.....but if i were to do it again, i'd consider a small port head.

you see plenty of people making 400+whp on small ports all day long....smaller ports allow for higher velocity (but lower flow)....the result....fatter mids and lacking highs. Sure we all want to drive a 700hp monster, but it's the area under the power curve that counts....

my $0.10 opinion:

1. Screw VVT
2. Whatever block you have is fine
3. Whatever head you have is fine
4. Rods are a must no matter what (although you will find several people above 400whp with stockers)
5. OBX, while essentially copying RMR's design, makes a product that is priced right for the market...no manifold is worth 800 bucks.
6. The only thing i miss with AEBs is that i do not have wideband feedback....MAF is a "reasonable" substitute
7. It's not the 70s anymore....no reason to run 8:1 compression....running stocker AEB pistons on both motors
8. Water injections is a cheap quick way to pull more timing/boost and essentially free HP

again, if you're shooting for the sky, do what you need to do....but 500whp is not the sky...any you can do that with either 20v motor setup.


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## rains (May 30, 2008)

thanks for the good pictures!

So, general consent is that this won't make much difference on a k03/ k04 powered car? Has anyone actually gone this route?


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## l88m22vette (Mar 2, 2006)

I'm going largeport because of my SEM and because I want the engine to be the best it can be, sure its not "necessary" but I hate doing things in 10 stages - I collect, button it all up together, and then am done. I'm shooting for 380whp from one of the new Garrett billet GT28s, VVT will help with lower-RPM power but my engine will also breathe well no matter what :thumbup:


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## Audiguy84 (Nov 14, 2006)

The large port head and bigger intake manifold will help the turbo spool faster as there is less restriction in flow.


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## audis3gr (Feb 23, 2009)

How thick is this construction?the
Plenum?the runners?


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## Doooglasss (Aug 28, 2009)

1/4" thick sides and I've drilled through the manifold in the plenum as well- it's thick enough to tap- looks like 1/4" to me too.


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## audis3gr (Feb 23, 2009)

Did you boost the car at high psi?
I want the same intake
For
My pte6162bb turbo at 33psi


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## iluvspdtt (Aug 31, 2010)

What fuel pressure regulator do you run with the rail on this manifold?


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## Doooglasss (Aug 28, 2009)

I've ran 38psi on a 5857 with this manifold. It can hold the pressure no problem.


I run an Aeromotive AFPR, surge tank, FueLab prodigy pump.


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## Alec's TT (Jan 28, 2013)

Instead of a new thread, lets keep going here. Does any one think that with a die grinder the inlet could be brought out to 75mm or so as to better accommodate a hemi tb? Anyone still running one that would suggest it? I have a few friends that have built hondas that they daily drive and also shred at the strip and it cost them a hell of a lot less in parts to get there and this looks legit to be honest, probably going to get one in a few weeks.


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