# Intake manifold Question



## WhyNot08 (Jul 17, 2008)

I am ordering a SEM intake manifold and i am not quite sure of the difference between the large and small port intake. I am running just a stock KO4 right now and suggestions on which one i should get.


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## amek0n3 (Sep 3, 2005)

you need a small port. 
if you had an AEB head (larger intake ports) then you would need a large port to match it.


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## WhyNot08 (Jul 17, 2008)

*Re: (amek0n3)*

Thanks that makes since.


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## l88m22vette (Mar 2, 2006)

*Re: Intake manifold Question (WhyNot08)*

Seems to me if you're going to spend $800 on an intake manifold you should at least know if your car is a big port or small port head







Are you chipped? What kind of mods do you have? Although a SEM will give more power it is way-overkill for the peashooter K04...


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## M this 1! (May 17, 2000)

*Re: Intake manifold Question (l88m22vette)*

That manifold is THE item to buy when you have a 3076 and bigger. if you're sticking w/ the k04...........don't get that intake, you'll do much better and save money on a different manifold. if you are going big, a 3076 is pretty damn big (500whp big).


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## SquashAZ (Apr 21, 2008)

*Re: Intake manifold Question (M this 1!)*

SEM claims 40 WHP on the stock turbo (12-14 lbs of boost), has any one actually installed one and realized the claimed added HP? 
http://semmotorsports.com/imag...i.jpg
If so than sight me up...


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## jwalker1.8 (Mar 4, 2008)

*Re: Intake manifold Question (SquashAZ)*


_Quote, originally posted by *SquashAZ* »_SEM claims 40 WHP on the stock turbo (12-14 lbs of boost), has any one actually installed one and realized the claimed added HP? 
http://semmotorsports.com/imag...i.jpg
If so than sight me up...









Sorry, you misinterpreted the info. This is comparing a stock TT 225 intake mani vs. the SEM mani....it is NOT a comparison done on a stock turbo...the turbo was a 3076 IIRC ran at low boost. Never anywhere does it say stock turbo.


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## SquashAZ (Apr 21, 2008)

*Re: Intake manifold Question (jwalker1.8)*


_Quote, originally posted by *jwalker1.8* »_
Sorry, you misinterpreted the info. This is comparing a stock TT 225 intake mani vs. the SEM mani....it is NOT a comparison done on a stock turbo...the turbo was a 3076 IIRC ran at low boost. Never anywhere does it say stock turbo.

DO I need a decoder ring? I reviewed the web page the plots were listed on and did see any reference to to the turbo?


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## [email protected] (Apr 25, 2007)

My dyno's have been conducted on a GT3076R at low and moderate boost levels.
We have gents running the intake on Stock TT 225's and Seat Cupra's and they comment on a power increase throught the rev range...Although, we have not conducted any dyno's yet.
If you guys like you can IM RobSonic for a testimonial


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## RobSonic (Sep 26, 2008)

Don asked me to chime in regarding the SEM manifold. I run a hybrid ATP GT2X turbo, so it's not a big turbo, a bit bigger than a K04 and rebuilt with uprated internals, larger compressor wheel etc.
I have a largeport SEM on a smallport engine, using the transition spacer. Initially using the 80mm TB I found it caused issues, so INA swapped it for me to a 70mm TB on an adapter plate.
Runs SO much better now, my car is flying, from my experience the SEM has given me more mid-range torque and power with awesome top end, improved throttle response too. No dyno yet but I know I have more power and torque now - no doubt.
The SEM is such a good design you should see gains in just about any application, plus it's a good investment if you plan to go big turbo in the future.


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## ugagirl85 (Dec 9, 2003)

*Re: Intake manifold Question (WhyNot08)*

There is no loss of low end and obvious gains up top. You'll make the same power at lower boost, or more power at the same boost as compared to the stock intake manifold. You don't need a 3076 to realize these gains. If anyone is interested in the SEM manifolds, you can email [email protected] with any questions.


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## M this 1! (May 17, 2000)

*Re: Intake manifold Question (ugagirl85)*

The factory didn't put the intake on the car 'cause they didn't know any better. they did it to best utilize the turbo and entire system. 
You're not seeing gains on a k04. it's like recommending cams for a k04!! it's stupid to recommend this guy spend $800 on this phenominal intake for his application. do the right thing and have him spend it on what WILL increase performance.
on a 3076 and up, it's a no brainer! period. the intake is insanely cool.


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## TToxic (Nov 15, 2008)

*Re: Intake manifold Question (M this 1!)*

X2- Every time a new intake comes out all the ko4 folks run out and drop the cash.
Few weeks later its the classic what did I spend my money on? type post remember
Dahlback Sheesh!.And as always Instead of taking someones hands on experience &
knowledge?


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## jwalker1.8 (Mar 4, 2008)

*Re: Intake manifold Question (TToxic)*


_Quote, originally posted by *TToxic* »_X2- Every time a new intake comes out all the ko4 folks run out and drop the cash.
Few weeks later its the classic what did I spend my money on? type post remember
Dahlback Sheesh!.And as always Instead of taking someones hands on experience &
knowledge?









I understand what you are saying but comparing the Dahlback to the SEM is apples to oranges...the Dahlback barely flows more cfm than the stock small port mani and the stock big port mani actually out flows the Dahlback...Dahlback FTL http://****************.com/smile/emthdown.gif 
yes, 800 on a near stock motor can be spent better somewhere else to start, but for an enthusiast looking to get the most out of his/her setup, the SEM is a good investment (especially if plans to go bigger are in the future)


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## TToxic (Nov 15, 2008)

*Re: Intake manifold Question (jwalker1.8)*



jwalker1.8 said:


> I understand what you are saying but comparing the Dahlback to the SEM is apples to oranges...the Dahlback barely flows more cfm than the stock small port mani and the stock big port mani actually out flows the Dahlback...Dahlback FTL http://****************.com/smile/emthdown.gif
> 
> Oh yea agreed - it was the biggest sham at the time, I know of a few who bought into it as well.
> If he is goin big t down the road great if not then dont ya think eight bills could get him further
> else where. I do, just an opinion


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## jwalker1.8 (Mar 4, 2008)

*Re: Intake manifold Question (TToxic)*


_Quote, originally posted by *TToxic* »_ dont ya think eight bills could get him further
else where. I do, just an opinion











_Quote, originally posted by *jwalker1.8* »_
yes, 800 on a near stock motor can be spent better somewhere else to start

Agreed


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## TToxic (Nov 15, 2008)

*Re: Intake manifold Question (jwalker1.8)*

lol did'nt spot the lower quote http://****************.com/smile/emthup.gif


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## 2001TTransport (Sep 18, 2005)

*Re: Intake manifold Question (jwalker1.8)*

Gee what to spend 800 on other than a manifold, I could think of alot of items; however, if his future path involves BT then nott a bad investment in his future if he gets a bigport with a adapter until he changes his head out for an AEB


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## [email protected] (Apr 25, 2007)

Agreed, you cannot argue with economics








BTW - this is what it looks like installed on a relatively stock TT 225


















_Modified by [email protected] at 8:38 PM 3-31-2009_


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## ugagirl85 (Dec 9, 2003)

*Re: Intake manifold Question (M this 1!)*


_Quote, originally posted by *M this 1!* »_The factory didn't put the intake on the car 'cause they didn't know any better. they did it to best utilize the turbo and entire system. 
You're not seeing gains on a k04
the intake is insanely cool. 

The factory did a lot of things that a lot of us change. lol The OEM manifold is fine for OEM power, which isn't what most of us are concerned with. Is the 225 manifold considered an upgrade to a 180hp motor (other than throttle placement)? No. Yet the 180's get a similar flowing intake mani. Why'd they do that?







You WILL see gains on a K04, especially a 225 K04-02x. I'm in the process of attempting to get a local to dyno a small port SEM on a 225 with chip and turbo back, hopefully it'll happen sooner than later. But you can't argue with efficiency, pressure, and flow. Removing restrictions from the intake tract, ie from compressor outlet to head ports, only allows more flow at the same pressure, or the same flow at a lower pressure. It's just like going from a restrictive IC core to a more free flowing one (disregarding cooling effects). The engine here is a compressor, with an inlet and outlet pressure. Lowering the inlet pressure (assuming no boost here, so really decreasing negative pressure), will raise volumetric efficiency. It holds true for ANY turbo. Yes, it is insanely cool.


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## jwalker1.8 (Mar 4, 2008)

*Re: Intake manifold Question (ugagirl85)*

Don, got any more pics of the TT? I am curious to see better shots of the Moshimoto intake.


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## [email protected] (Apr 25, 2007)

*Re: Intake manifold Question (jwalker1.8)*


_Quote, originally posted by *jwalker1.8* »_Don, got any more pics of the TT? I am curious to see better shots of the Moshimoto intake.

No more shots sorry...I had that intake taken off. I don't recommend it.


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## SteveCJr (Aug 3, 2008)

*Re: Intake manifold Question (jwalker1.8)*


_Quote, originally posted by *jwalker1.8* »_Don, got any more pics of the TT? I am curious to see better shots of the Moshimoto intake.

















Why would you not recommend it? Just curious. If I knew anything back when I bought it I wouldn't have. It's not even what I wanted but it came and there it is.


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## M this 1! (May 17, 2000)

*Re: Intake manifold Question (SteveCJr)*

I definitely like to see those dynos! especially since 2871 and so far as i've found 3071 aren't seeing improvements that i can find. it's similar to why i've not done head work w/ my 2871. my stock head can flow anything my 2871 can throw at it. by doing headwork, i loose bottom end but do not get enough of it, if any at all, back at the upper end. 
basically my point is this, if he's doing a k04, 28xx, 3071, he could get a MUCH cheaper manifold to be better than stock AND flow just as well if not better than the SEM........up to those turbos i listed.









BUT if he's going 3076, buy that damn SEM now! because almost every other engine mod you've bought for the k04 set up will be thrown out! hell i thru out my Forge FMIC when i went up in turbo. pick your end result now, find a path to follow, and stay on it! i'd love to be able to do a 2.0, 3076, SEM and matching head but i don't really need more power and speed







and my wife would kill me.


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## [email protected] (Apr 25, 2007)

*Re: Intake manifold Question (SteveCJr)*


_Quote, originally posted by *SteveCJr* »_
Why would you not recommend it? Just curious. If I knew anything back when I bought it I wouldn't have. It's not even what I wanted but it came and there it is.









Just the mere fact that it threw off the MAF readings a bit along with the trims. This was on an APR chipped car.


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## l88m22vette (Mar 2, 2006)

*Re: Intake manifold Question ([email protected])*

Intake + 1.8T = sound, not power


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## XXX 1.8T (Aug 10, 2002)

*Re: Intake manifold Question (l88m22vette)*

where do you get the mobil 1 stickers from or is that from the dealers?


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## SteveCJr (Aug 3, 2008)

*Re: Intake manifold Question ( XXX 1.8T)*

was on it when I bought it


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## [email protected] (Apr 25, 2007)

*Re: Intake manifold Question (SteveCJr)*


_Quote, originally posted by *SteveCJr* »_was on it when I bought it

All good http://****************.com/smile/emthup.gif If you have the stock Airbox try that and log the MAF using Blocks 002 vs the Mushimoto.


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## ny_fam (Apr 3, 2004)

*Re: Intake manifold Question ([email protected])*

Interesting thread - 
I know I'm not the first to test out the 1.8T intake but I know the stock intake flows very bad. Even in comparison to other VW and Audi intakes like the 80's Rabbit intake.
When its ported it flows fairly well, Its hard to believe that some modest gains aren't had with a better flowing intake. If you looking at just how well each of the parts flow in the intake track, the manifold flows in the 150 cfm range. The head must flow close to 200 cfm or more stock. 
Here are my test results. Local VW club will by doing a back to back dyno of this intake in a month or so.
http://www.scientificrabbit.com/node/8 
Cheers
ny_fam


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## [email protected] (Apr 25, 2007)

*Re: Intake manifold Question (ny_fam)*

Interesting indeed...
I thought I might add to this...Bill Brockbank (Badger-5) took the opportunity in having his LP 80mm SEM intake flowed by http://www.JNLRacing.com.

_Quote, originally posted by *Badger-5 Email Correspondance* »_From: JNL Racing <[email protected]>
Subject: SEM Manifold test results
To: "BILL BROCKBANK" <[email protected]>
Date: Wednesday, 15 October, 2008, 12:21 AM

Overview
Mathematically the internal runner size on each runner has an identical cross sectional area to the intake mouth of a big port head if we make the assumption it is a perfect rectangle. Obviously we are in a scenario where in real life the intake has radiused sides so there is mathematically scope to open the mouth of the cylinderhead port further than the standard port mouth size without loss of flow. Further experimentation would have to be done to actually work out what the threshold is and as to how much effect the port design has on it.
Testing Method
The flow results of each individual runner Number 1 being closest to the throttle body which in this case cyl number 4 closest to the gearbox. All flow figures have been pulled at 10" on a digital bench calibrated to a superflow 110 with allowances for atmospheric conditions whilst tested. A calculated equivalent using a 1.673 correction factor has also been made for a 28" test pressure result for comparison with existing results from other sources. From experience time and time again the mathematical 10" to 28" conversion actually yields results 1-1.5% lower than an actual tested 28" at flow figures between 250-300cfm. On the individual runners 3 seperate pulls where made at different bench operating temperatures (heat build up over time from extended running of the motors) and an average taken from the results.
CFM Report
Percentage variation between each of the individual runners is a maximum of 1.54% between the highest and lowest. An acceptable variation for high performance mapping purposes when using a single lambda probe to determine the average of 4 cylinders is considered to be 3-4% deviation from minimum to maximum. So the manifold falls well below this safety range.
FPS Report
At 10" test pressure port/runner velocity is considered at choke at 209fps which equates to 350fps at 28". The runner velocities where measured as central as possible to the runner at the cylinderhead flange exit/entry point. Higher velocities where recorded towards the sides however it was difficult to record a constant across the 4 runners for comparison so it was decided to take the lowest velocity found at the centre of the runner as the comparison point. As can be seen all runner velocities far exceed choke point which within a cylinderhead port would be considered detrimental to the power output of the engine (similar to running too much timing advance). However such characteristics in a manifold can be deemed beneficial in improving throttle response at certain points in the rev range. 

SEM Manifold Results
Test Pitot SCFM 
Intake Pressure FPS 
1 10 269 162.3 
2 10 282 164.5 
3 10 287 164.8 
4 10 288 162.4 
Test Pitot SCFM 
Intake Pressure FPS 
1 28 450 271.6 
2 28 472 275.3 
3 28 480 275.8 
4 28 482 271.7
Flow test involving a mildly ported testhead
As an experiment we have also taken a mildly ported large port head with standard port mouth sizes to mate up to the SEM manifold. (Again flowed at a 10" test pressure). As you can see although there is a drop it is considered quite minor in the grant scheme of things averaging between 2.5-3% drop across the complete lift range.
The most surprising thing here though is that although runner 1 flows physically worse than runner 3 it only exhibits a 2.5% drop across the range against the 2.9% drop of runner 3 which will be down to the slower runner velocities that were recorded. Which goes to show that runner flow without the equation of the head can be quite deceptive and should only be taken as a guideline as to how well they are matched to each other not of their final ability. I also shows that port/runner velocity plays an important part in final combinations.
Common to both runners tested on the head; when measuring port/runner velocity at the port mouth of the head with the intake bolted on the port velocity became approximatelly the average of the two items when tested individually.
For example runner one measured 269fps on it's own and port 1 measured 227fps on it's own. Once the intake was bolted onto the head the port/runner velocity averaged out at 245fps. (All three velocity measurements taken as central to the runner/port as possible).

Final Overview
The SEM manifold for use on a standard head application will potentially see small gains in tq and hp in the mid to top range over a standard manifold due to the high runner velocities, providing it is correctly matched with the right throttle body (not too large) there will be improved throttle response over a standard manifold. There may be a small sacrifice of power in the low rev range as it will take extra time to fill the larger plenumb chamber however this would have to be tested on a dyno to verify. 
For big power/high rpm application it would be considered a highly desirable manifold to have specifically because of the large plenumb chamber giving a large storage capacity of boost pressure for the cylinders to draw from. This means less of a pressure drop during gear changes and would be ideally suited to track orientated vehicles whether drag or circuit. For drag race/big turbo - high boost application it would be advised to open the ports up to slow the runner velocities down accordingly, whereas circuit cars with smaller turbo's and lower boost settings will benefit from the higher velocities for out of the corner throttle response on the standard port/runner size. *Comparing the figures of the SEM manifold against existing test results floating around the net not only does it outflow the best manifolds out there at the moment but it is also the most consistant across all four runners even outdoing my previously favoured RMR manifold which has a
2.8% variation across the runners.*
Courtesy of http://www.JNLRacing.com
Feel free to recirculate as desired, I've also attached a few dodgy pics of the phone of the setup. Unfortunatelly my camera battery went flat and didn't have a charger on me. At one point I'll do the AGU intake aswell as the AEB to compare it to. However I've just hit a massive back log as I'm taking delivery of another 4 jobs tomorrow so probably wont get onto it for at least another 2-3 weeks. Will get the manifold back in the post tomorrow by Special delivery as the couriers wont insure it. If you can also get me a price on a big port one for Karl as he's going to be needing one. I'll have to confirm throttle body choice before order though as we dont want it too big. For some reason the VAG turbo boys in America haven't realised yet that a forced induction engine favours a smaller throttle body than naturally aspirated. Same reason if you look at a small block chevy with a supercharger and a blow through carb setup they make the carb for
supercharger use out of a 750cfm body whereas a naturally aspirated equivalent engine would run either an 850 or 950cfm carb depending on cam and head spec.

-- 
Kind regards
Jean-Paul
http://www.JNLRacing.com


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## ny_fam (Apr 3, 2004)

*Re: Intake manifold Question ([email protected])*

would like to see the CFM on the manifold/head combo and head alone too.
I've got to get a setup to measure fps. Nice info though.
"For example runner one measured 269fps on it's own and port 1 measured 227fps on it's own. Once the intake was bolted onto the head the port/runner velocity averaged out at 245fps. (All three velocity measurements taken as central to the runner/port as possible)."
Interesting the intake at 269 fps and the head at 227 fps then the combo split the difference.
Would be interesting to see what CMF and thus the velocities are found in the runners under load. 400 fps the choke right?


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## JNL (Dec 13, 2007)

*Re: Intake manifold Question (ny_fam)*

^^^^ @ ny_fam
If I get a moment I'll have a look for the cfm file I don't tend to make too much of cfm figures though when 1) it comes to multi valve intakes and 2) boosted application. might be an idea to email me as I don't often return to posts as it is one too many things on top of everything else to keep track of.
Firstly at 10" choke is considered to be 209fps so a large port 1.8t head that has been mildly ported already exceeds that at high lift. Which is one of the reasons they don't respond aswell to high lift cams when turbo charged opposed to naturally aspirated application. As the extra pressure from the turbo just makes the choke come in at lower lift anyway.
A good real life comparison is that of the intake ports of the 2.7t RS4 heads vs those of the v6 2.8 heads both 3valve intake like the 1.8t.
The 2.8 heads are pretty much identical to the AEB head in port design other than that they are a nicer casting. The result of which is that the 2.8 heads flow the same as a mildly ported AEB head which is approx 140cfm @ 10". Both with ridiculously high port velocities at high lift screaming big time as airflows through them (loud whistling noise from turbulance).
Compare them to the RS4 heads which are the same 3 valve intake but a totally different port workup. These only flow around 120cfm @ 10" but at much slower and more stable port velocities evenly spread across the cross sectional area of the port.
In real life in with identical setups turbo wise the RS4 heads produce more top end power and have better low to mid throttle response. 
Hence I was more interested in the percentage restriction on flow of the SEM intake rather than actual figures and more interested in the effect of port velocities
As for porting standard intakes yes there is gains to be had when done correctly the biggest issue again is keeping velocities correct or you kill of the bottom end and mid range. With the biggest issue on the standard intake design being that the runner closest to throttle body tends to run lean at high rpm on increased boost application comparitivelly to the other 3 cylinders. This is down to there not being enough boost reserve in the plenumb chamber to equally feed all 4 runners at high rpm. So the resulting effect is that the boost charge entering through the throttle body ends up being swallowed by the runner closest to it instead of charging up the plenumb. Unfortunatelly this cannot be overcome by porting. The smaller plenumb is also why on a WOT 2nd gear pull you'll see the boost spike and then drop of through the rev range as the engine consumes more than the turbo can supply. Increase the plenumb chamber volume and the peak boost will hold proportionally for longer through the rev range giving improved midrange to top end power even on a small turbo. The key on a smaller turbo is not to go too bg on the TB. (65mm favoured on a K04).
I had a similar dilemna on a G60 setup the other month where the standard intake killed the flow figures by over 10% across the lift range. The first response was to chop the plenumb open so I had full access to the total runner length, radius everything nicelly and max the lot out. It still showed a 5-6% loss depending which runner but totally messed up the port velocities. So I took a different line of attack and left the upper part of the runners alone concentrating on making the lower half upto the bend correct and leaving the upper half alone. It ended up making zero loss at the low lift range, actually picked up as much as 2% in the mid lift range and only lost between 2-3% at the very top end of the lift range with improved runner and port velocities. 
As for the comment earlier by M this 1! Regarding head porting on a GT2871. I will beg to differ as will many of my customers. A "Correctly" ported small port head on a GT2871R with 0.86 backhousing will reliably give 450hp at the fly with a smooth factory feel power curve through the rev range instead of nothing and then everything big turbo aftermarket feel, it will give improved throttle response and part throttle driveability. Substantial low down torque increase with much improved on/off throttle spool up. One tuner ran his GT2871R upto 2.3bar commenting on how easy it was to map as the boost was so controllable and made 497hp on an engine dyno on a standard BAM setup other than a tubular exhaust mani. 
A good example of porting a head on small turbo application and mapping to suit is my daily driver an Audi S6 with a 2.2 inline 5 on a standard K24 turbo. From facory these cars produce 230hp/200tq at the flywheel. Mild headwork for turbo spec and a 3" exhaust with a remap has yielded the same peak 280hp that everyone claims on just a remap. except instead of 270 - 280ft/lb mine produces 339ft/lb with a totally flat power curve. On part throttle the car pulls to 160mph without trying just as easily as it does on full on an aerodynamic brick that weighs 3800lbs. One customer that has the same engine in a S2 (approx 3200lbs in weight) producing 380hp on a bigger turbo with no headwork commented how my car felt faster than his. It's all about making the engine as efficient as possible and making the turbo work freely instead of trying to ram air down something that doesn't want it. 
Remember when you look at the pressure on your boost gauge you are taking a reading from the plenumb chamber which means you are measuring what is left over and the engine can't swallow. Make the engine swallow more through headwork and the turbo has got to work harder and produce more air to sustain the same boost pressure. Instantly as you are producing more airflow you produce more power.



_Modified by JNL at 12:26 AM 4-6-2009_


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## M this 1! (May 17, 2000)

*Re: Intake manifold Question (JNL)*

Interesting take. But then since most throw away the small port head.........who do you trust in doing this correct porting?


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## JNL (Dec 13, 2007)

*Re: Intake manifold Question (M this 1!)*


_Quote, originally posted by *M this 1!* »_Interesting take. But then since most throw away the small port head.........who do you trust in doing this correct porting?

Couldn't tell you in the US as I only hear of the US boys using the AEB heads. Whereas 90% of my clientelle in the UK do small port heads hence my experience with them. 
Even UK's fastest MK1 Golf which runs 10.21secs on the quarter runs a small port head with standard valves. The turbo he uses is a GT3071 .82 housing, 1.8bar is good for 500hp give or take 1 or 2hp at the flywheel.


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## M this 1! (May 17, 2000)

*Re: Intake manifold Question (JNL)*

definitely great info, now to be able to get the specs or there abouts on what they're doing to that head!
Thx for the info


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## ny_fam (Apr 3, 2004)

*Re: Intake manifold Question (M this 1!)*

This is the shop I'd recommend. http://www.aftracingheads.com/
I use that shop from my custom work. They have very good experience with a wide range of very high profile race cars/trucks etc.


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