# A Brief History (2.5L + Performance + Dyno Charts + Build Thread)



## H3LVTCA (Oct 27, 2004)

It's taken me a while to finally write this novel of a thread, but I hope it encourages discussion and it helps other 2.5L owners.

In February/March of this year, I came across some (what I felt) really good deals on a gently used Magnaflow exhaust and a never-used Eurojet header. 








I’d owned my 6-speed automatic 2008 Rabbit for a little over three years and wanted to begin modifying it beyond aesthetics. (I didn't want to delve into turbocharging the car for a number of reasons.) But I wanted to “do it right,” so I read up on exhaust headers and eventually even went and had it ceramically coated (to encourage heat resistance) before installation. 















In addition, I was going to get Unitronic’s Stage 2 software installed simultaneous to the exhaust and header. I thought that doing all three of these upgrades would make a respectable, but not enormous, difference in the power my car was creating. Since there hadn’t been too many other 2.5L owners that had done such modifications, I was going to document the transition though dyno’ing the car after each mod.

After all, Magnaflow posted a Dynojet graph declaring a “10HP & 10LB•TQ Gain!” from the exhaust on a 2007 Rabbit. 
(Granted this was the year where the engine was rated at 150HP, not 170HP like 2008+ years.)









Eurojet was claiming “Dyno-proven HP gains,” on every retailer’s website, without any dyno graphs.
Unitronic suggests a  “15HP & 13LB•TQ” gain, albeit also without any dyno graphs.

Now granted, Unitronic’s numbers are going to be at the engine, not the wheels, for horsepower and torque gains. Which is why, quite honestly, I’d be more inclined to believe Unitronic’s claimed numbers out of all three manufacturers, because they do the testing with just the engine outside of the car. As we all (hopefully) know, there is approximately a 15% drivetrain loss, so let’s assume for the sake of argument that Unitronic’s software actually puts out around 12HP and 10LB•TQ. If you’ve been paying attention, the hyperlink above was to Unitronic’s Stage 1+ software, not Stage 2 - I’ll get back to that in a few paragraphs.

I brought my car to Mobile One in late April of this year. Aforementioned, I wanted to “document” the progression from stock to modified by dyno’ing the car after each installation. Mobile One has a Dyno Dynamics dynamometer, which have been known to be brutally honest about the power your car is delivering to the wheels. I don’t care to argue about Dyno Dynamics VS. Mustang Dyno VS. Dynojet. 

The first dyno graph revealed almost exactly what I was expecting - about a 15% loss in the horsepower and torque figures that Volkswagen suggested for that year - 170HP & 177LB•TQ x 15% (loss) ≈ 144HP & 150LB•TQ: 









The shop then installed the header and exhaust, and dyno’d the car a second time. The posted dyno results from Magnaflow of 10HP & 10LB•TQ from their exhaust - in addition to Eurojet’s claim of “Dyno-proven HP gains,” I was expecting a result of maybe 15HP & 15LB•TQ. Two runs in, the results show a gain of almost 14HP and 5LB•TQ:









After searching the databases and eventually calling Unitronic, Mobile One couldn’t find the Stage 2 software for my Rabbit’s engine/transmission combination, so they flashed my ECU with Stage 1+. The owner of the shop (Jason) even called Unitronic’s headquarters to escalate the problem and explained that he’d notify me once Unitronic notified him of the release of Stage 2 for my drivetrain combination. He also mentioned to them that I had a Eurojet header and a Magnaflow exhaust installed, so maybe they could further tune it for me. After Stage 1+ was flashed, the shop dyno’d the car a third time, but the results were interesting. To our surprise, we saw a decrease of about 6HP when this software was installed:









Mobile One kept in contact with both Unitronic and myself on the status of my Stage 2 file until July. After nearly five months of testing, Unitronic adamantly concluded that the Eurojet header that I have installed, actually *lost power* when tested by them on their engine dyno with my specific engine/exhaust/header combination. The shop and myself were surprised, and not quite sure how it's possible. Obviously they are not going to spend any time making a file for a piece of hardware that produces negative results. 

I plan to remove the Eurojet header and replace it with the stock header, then dyno the car again to see the results. 
It’ll be interesting to see what the outcome is. 

If something positive has come out of all the work that’s been done thus far is how gnarly and unique my exhaust note is. 




Really laying into the throttle brings a smile to my face. My girlfriend has a 2010 Jetta with the same engine/transmission combination and in comparison, the Rabbit is undoubtedly quicker. It's difficult to describe, but the car pulls away smoother and it's a lot more fun to drive.










I went into this blindly, not knowing what to expect. If there's one thing I've learned, it's to patiently wait for the _proven_ numbers by a manufacturer. A lot of us 2.5L owners are holding on to our money, waiting for new and improved performance parts to arrive. Keep waiting, there's a lot of stuff on the horizon and I have a feeling 2012 will be a good year for us. 

I'd still recommend Unitronic software and the Magnaflow exhaust to any 2.5L owner. Unitronic put in the hard work behind the scenes to finally reach an (unexpected) outcome. I also highly recommend Jason and the team at Mobile One in Glenview, IL. 

I plan to continue updating this post. 
In a way, it’s my build thread.

*PERFORMANCE MODIFICATIONS* (as of 12/6/11)
•Eurojet Stainless Steel Exhaust Header
•Magnaflow Stainless Steel Cat-Back Exhaust 
•Unitronic Stage 1+ Software

Added 8/6/12
•Black Forest Industries Stage 2 Transmission Mount
•Black Forest Industries Stage 2 Torque Arm Insert


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## thygreyt (Jun 7, 2009)

awesome.. now i want to do a dyno! lol...

as per the headers loss, i think that if you were to add an intake mani, you'd see better gains.


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## itskohler (Jan 7, 2011)

Interesting the the headers caused that issue. 
Sub'd.


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## DerekH (Sep 4, 2010)

thygreyt said:


> awesome.. now i want to do a dyno! lol...
> 
> as per the headers loss, i think that if you were to add an intake mani, you'd see better gains.


I would say even just a cold air intake would help out a lot.


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## bunnyfufu (Jan 25, 2011)

itskohler said:


> Interesting the the headers caused that issue.


my thoughts exactly.. i mean some low end torque loss would be expected but an overall loss of power doesnt make sense. 


@ OP either way good to see others are still interested in the 2.5l. good luck with build


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## pennsydubbin (Mar 3, 2010)

my guess is that the stock airbox is limiting the amount of air in while the full exhaust is allowing too much out.

I'm sure an intake will solve this problem and an SRI will make it perfect.

edit: This is with the assumption that you do not have an intake already


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## thygreyt (Jun 7, 2009)

i would assume he as an intake...


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## itskohler (Jan 7, 2011)

Exactly what I was thinking. the amount of back pressure needed is something that can be debated, but if you dont have more air passing through the engine, you really don't *need* the exhaust headers. 

It's good that he has those though, it's almost all down hill from there. :thumbup:


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## pennsydubbin (Mar 3, 2010)

i would hope he does too, but i don't see it ever mentioned that he has an intake.


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## lessthanalex (Oct 12, 2009)

This is very interesting to see. I'd like to know if there would be a difference with moving to a stage 2 file. OP you should post up a comprehensive list of all mods you have that will affect the dyno. 

Sent from my BlackBerry 9700 using Tapatalk


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## bunnyfufu (Jan 25, 2011)

lessthanalex said:


> OP you should post up a comprehensive list of all mods you have that will affect the dyno.
> 
> Sent from my BlackBerry 9700 using Tapatalk


2nd this


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## jaja123 (Jan 17, 2011)

yo broski are u in chicago? I went to mobile one too and got a dyno on my 2010 golf. 163whp, 156ft tq with intake and 2.25 catback with crush bends.


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## vento 95 GL (May 25, 1999)

Like the others said, you should put a cold air intake like bsh or carbonio or short ram like neuspeed and dyno again before getting rid of the headers.

The biggest bottle neck on this engine is the airbox. just putting an air intake yields some good results. 

give it a go, you might be surprised with the results.

edit: if you already have an intake then I have no clue...


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## H3LVTCA (Oct 27, 2004)

DerekH said:


> I would say even just a cold air intake would help out a lot.





pennsydubbin said:


> I'm sure an intake will solve this problem and an SRI will make it perfect. My guess is that the stock airbox is limiting the amount of air in while the full exhaust is allowing too much out.





thygreyt said:


> I would assume he as an intake...


I think you're all right - an intake would help the situation but I don't have one on my Rabbit. 
I did pre-order the BSH intake when it was first released; soon after it arrived and I read the installation instructions about cutting the wiring loom to re-route the MAF sensor, I decided against it. I've heard that they've re-done the installation procedure, but that kind of worried me. 

I do have my eye set on the Neuspeed P-Flo intake, and I plan on installing in addition to an intake manifold once they become more widely available for the 2.5L.




lessthanalex said:


> I'd like to know if there would be a difference with moving to a stage 2 file. OP you should post up a comprehensive list of all mods you have that will affect the dyno.


 I have update the original post with the list of "performance" modifications currently on the car, which really are the three that I talked about in the original thread.


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## DerekH (Sep 4, 2010)

You don't cut the wires you just separate the wires from each other, no big deal.


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## Monkeyslord1 (Jun 9, 2009)

^ like said above, you just carefully cut through the tape and separate the wires of the MAF sensor from the other wires, tape them back up and have the wires that go to the MAF on the right side of the battery coming to the front rather than behind, if u wanna see how i did it just pm me and ill send u a pic....there really wasnt anything difficult to do in the installation.


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## LampyB (Apr 2, 2007)

^ it's not difficult, you just need a small pair of finger nail scissors to cut the tape wrapped around the wiring harness. nail scissors were the best recommendation given to me, as they are very sharp, and very small so that you don't accidentally slice anything on accident! :laugh:


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## jaja123 (Jan 17, 2011)

have you looked at the carbonio intakes?.


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## b1aCkDeA7h (May 27, 2008)

I'm planning to get C2's SRI Installed at the end of the month as well as a Eurojet Header and Eurojet High Flow Catalytic Converter.

Currently have a Neuspeed Intake and Techtonics Dual Borla Exhaust so I'm curious as to what my car will put down in the end, especially after reading this thread. Unforunately, I'm not sure when I'll ever get the car dyno'ed but I'm still looking forward to the finished product nonetheless.


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## halbwissen (Jul 20, 2001)

H3LVTCA,

That you for your contribution to the forum. :beer:


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## nothing-leaves-stock (Mar 1, 2005)

good info. thanks for sharing.
we found the same with the EJ header/test pipe combo.
best header/test pipe to MAKE power is the EVO header. designed right to make power. not just to look good.


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## DerekH (Sep 4, 2010)

nothing-leaves-stock said:


> good info. thanks for sharing.
> we found the same with the EJ header/test pipe combo.
> best header/test pipe to MAKE power is the EVO header. designed right to make power. not just to look good.


I would imagine a proper tune makes all the difference with the ej header. Seeing as the evo header is similar in size to the stock mani, where the ej header is enough different the programming could be optimized better. However you would know better than me.

Also, i do remember seeing a dyno chart for the ej header on a stock car and it only making a few peak hp difference but bumping the power up all along the curve. Could be mistaken though it was probably more than a year ago now so it could be something else that i am thinking of.


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## thygreyt (Jun 7, 2009)

DerekH said:


> i do remember seeing a dyno chart for the ej header on a stock car and it only making a few peak hp difference but bumping the power up all along the curve. Could be mistaken though it was probably more than a year ago now so it could be something else that i am thinking of.


i have seen it too... but long ago.


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## H3LVTCA (Oct 27, 2004)

DerekH said:


> You don't cut the wires you just separate the wires from each other, no big deal.





Monkeyslord1 said:


> You just carefully cut through the tape and separate the wires of the MAF sensor from the other wires... there really wasn't anything difficult to do in the installation.


Don't get me wrong, I'm not doubting the difficulty of the installation, but cutting the wiring loom open as it was suggested just didn't feel like a good idea to me. The last thing I wanted to do was to screw up the wiring/electrics of a new car.


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## H3LVTCA (Oct 27, 2004)

DerekH said:


> I do remember seeing a dyno chart for the ej header on a stock car and it only making a few peak hp difference but bumping the power up all along the curve. Could be mistaken though it was probably more than a year ago now so it could be something else that i am thinking of.


 If anyone stumbles across that dyno chart, I'd love to see it/put it in the original post.


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## nothing-leaves-stock (Mar 1, 2005)

long tube headers...good tune or not will kill power if not matched to the motor output. long tube headers take a lot to make right.


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## spdfrek (Feb 28, 2002)

H3LVTCA said:


> If anyone stumbles across that dyno chart, I'd love to see it/put it in the original post.


I think this is the one.


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## spdfrek (Feb 28, 2002)

nothing-leaves-stock said:


> long tube headers...good tune or not will kill power if not matched to the motor output. long tube headers take a lot to make right.


Same thing with a short runner intake. If its not matched to the motor it will loose power.


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## H3LVTCA (Oct 27, 2004)

spdfrek said:


> I think this is the one.


The folks at Evolution Tuning have made their dyno chart. I'd love to find the one put out by Eurojet.

Additionally, seeing as all of their products have dyno chars accompanying them, I may opt for one of their intakes instead of Neuspeed when the time comes.


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## tay272 (Aug 22, 2007)

If I wanted to get a short ram intake then Id go with the Evo one. The filter itself has a built in velocity stack to help funnel air in through it from all areas and reduce any kind of turbulence. Seems like the best one out there to me. Reading through your thread tho has made me rethink getting headers for my car, and if I do Ill most likely go with the Evo ones as they are proven to make power with my current setup. They cost a **** ton of money but Im sure theyre worth it.


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## b1aCkDeA7h (May 27, 2008)

tay272 said:


> If I wanted to get a short ram intake then Id go with the Evo one. The filter itself has a built in velocity stack to help funnel air in through it from all areas and reduce any kind of turbulence. Seems like the best one out there to me. Reading through your thread tho has made me rethink getting headers for my car, and if I do Ill most likely go with the Evo ones as they are proven to make power with my current setup. They cost a **** ton of money but Im sure theyre worth it.


I was about to do the same header-wise, then Bluewater went and put up a barely used Eurojet header and high flow cat at too good of a price to pass up. I've heard Evo headers come ceramic coated, a definite plus. I'm going to try and ceramic coat my newly acquired Eurojet stuff before the install at the end of the month.


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## DerekH (Sep 4, 2010)

nothing-leaves-stock said:


> long tube headers...good tune or not will kill power if not matched to the motor output. long tube headers take a lot to make right.


Any chance you can enlighten us as to what has to be done to make it right? I'm not really sure what you mean, and if i can do some tweeks to get my car running better it would be cool. But I'm assuming its going to be more than tweeks.


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## spdfrek (Feb 28, 2002)

H3LVTCA said:


> Additionally, seeing as all of their products have dyno chars accompanying them, I may opt for one of their intakes instead of Neuspeed when the time comes.


Honestly I don't think you will see any measurable differance in either intakes or any other for that matter. Where you will see a differance is in different intake manifolds because the differance in plenum size and shape and runner length.

I had a VF intake on and swapped to a Neuspeed because I needed that little bit more clearance to fit the oem hids. I didn't notice any chance in power or even throttle responce.


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## nothing-leaves-stock (Mar 1, 2005)

the long-tube's torque and horsepower curves lasted longer (most of the tim), suggesting that these headers would indeed make even more power over short-tube headers* if used on a more modified engineand higher RPM*(will make more power at higher RPM). This is due to the fact that a long tube header can make use of the engine's exhaust pulses to "pull" exhaust gas from the cylinder, providing optimized scavenging. A short-tube header, with its much shorter primary tubes, simply does not have the same advantage. 
One of the things that impacts on exhaust scavenging is the duration of the exhaust pulse, which is inversely proportional to engine RPM. If you have relatively long primaries, the exhaust pulses are less likely to interfere at low RPM at the collector and more likely to assist in the evacuation of the other primaries, increasing efficiency. The easier your engine can "exhale" the more fuel-air mix it can process and the more horsepower it can produce.
so in short....a shorty header will be best with 99% of you guys because you all have STOCK motors, stock comprssion etc. just doing bolt on's won't help a TON to make the header work proper.


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## DerekH (Sep 4, 2010)

So not even an SRI would make a difference with the long tube header? From what I'm gathering you are talking about valve train so you can rev higher. Which makes sense really. this engine seems to just get started past 6k with an sri.


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## nothing-leaves-stock (Mar 1, 2005)

yes a sri will help a BIT....because higher rpm's.


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## DerekH (Sep 4, 2010)

nothing-leaves-stock said:


> yes a sri will help a BIT....because higher rpm's.


Would you say that you are better off with the stock exhaust mani over a long tube header with an sri? Just curious, might sell my header and get an sri if that is the case. Don't really feel like taking it off though lol


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## nothing-leaves-stock (Mar 1, 2005)

IMO. if you have to choose between a SRI/software and a header/test pipe?
go with the SRI/software.
then add header LATER...but i'd say a EVO header.
but i'd do a sri/software 1st, you'll see a better gains this way.

we did over 200whp with a sri, software, evo header, test pipe and 2.5'' exhaust.


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## mk racer (Jun 28, 2007)

I have an 09 rabbit, and I have an sri, eurojet headers and full 2.5 exhaust and unitronic stage 2 flash, which mobile 1 did for me, and I've got an appointment with them for an exhaust leak repair, but I said to throw in a dyno run or two so I will be posting up a video and some numbers later tomorrow. Im debating whether or not to toss the headers and go back to the stock exhaust manifold, see which gives me a few extra horses


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## spdfrek (Feb 28, 2002)

Damn everyone is getting dyno time at Mobile One. I really need to stop by the shop and hangout more like I used to. :beer:


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## madbikes (Dec 30, 2010)

This is definitely a good read. I'd like to dyno mine some day.


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## thygreyt (Jun 7, 2009)

do it! 

then post them all


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## TylerO28 (Jul 7, 2008)

I have an OEM header for sale if anyone needs one! And the stock cat/down pipe! Could easily be modified should anyone decide they would like to keep some back pressure! Any takers? I'm seriously angry they are sitting in my garage!

Regardless, please post up comparisons for the n/a crowd! I'm really surprised by the OEM header! Its very strange looking, doesn't seem to have runners, almost instant 5 into 1 with a plenum in there


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## thygreyt (Jun 7, 2009)

it does kind of have runners, they are hidden inside the shell


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## nothing-leaves-stock (Mar 1, 2005)

have you cut oe open?
they don't have any runnings. just little sections...its wierd, but no runners


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## thygreyt (Jun 7, 2009)

nothing-leaves-stock said:


> have you cut oe open?
> they don't have any runnings. just little sections...its wierd, but no runners


I saw a pic from vw' s training pdf

sent from tapatalk


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## pennsydubbin (Mar 3, 2010)

lol and then if anyone else wants stock headers I have 2


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## nothing-leaves-stock (Mar 1, 2005)

we cut up a exhaust AND intake manifold...both interesting


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## spdfrek (Feb 28, 2002)

TylerO28 said:


> And the stock cat/down pipe!


If you were closer I might be interested but with shipping it wouldn't be worth it.


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## H3LVTCA (Oct 27, 2004)

Finally got around to editing a teaser video I shot with my new GoPro!


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## Gans (Oct 31, 2004)

Great thread!! :wave:


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## itskohler (Jan 7, 2011)

MOAR POWER!

Nice thread. Makes me wish I had started something like this. I would hold on the the headers and just add the SRI in there with a 2.5in exhaust like mk racer did. :thumbup:


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## 2.5low (Mar 13, 2012)

MK racer... what happened with the dyno? im in a pending with a eurojet header as we speak and would like to know what your outcome was.. considering i dont have sri, id like to know if anyone has this combo.

Intake+SRI+Eurojet headers+Exhaust(awe)+Tune=???


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## Rabbidrabbitt (Mar 21, 2011)

Intake,Sri and sri tune you will be ecstatic. Worry about exhaust and headers later. Headers are a bit of a pain to install Sri overall easier install. When you add it up Headers anywhere from 250 to 1k ,16 lugs and bolts about 1 to 3 dollars a piece (you need longer lugs and have to take out old ones good luck) custom mid pipe 20 to 100 dollars, high flow cat or test pipe 100 to 300 dollars, exhaust 300 to 1000 dollars + labor and hardly any hp gains or 100 to 300 on intake and another 1300 on sri and tune and a hour install and you will have a N/A car that will give GTI's a run for their money. Save and do it the right way if you can get the eurojet headers at a good price get them but you will be disappointed with just headers. Trust some of us that have gone through the headaches that you wont have to endure


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## 2.5low (Mar 13, 2012)

well the install wouldnt be untill mid summer anyway.. EJ headers come with test pipe.. hoping to do the install altogether.. c2 sri so i dont have to get new plumbing.. not sure what software.. prob um.. due to less problems.. being most had to send back ecu or ran into probs with the tune unless they were at the shop from what ive read and gathered.. no exhaust yet so id have to wait regardless.. its really going to be a few months to get everything and the cash to do so..

hoping i was one of the mega winners...


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## Rabbidrabbitt (Mar 21, 2011)

I have not had any problems with my C2 tune and SRI and I was one of the first Rabbits to have the C2 SRI and Tune. And You do not need exhaust to Run the short runner.


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## thygreyt (Jun 7, 2009)

You sure can. But as it was said before: first go with a mani, then with the headers. Manis will yield more power.

And yes, um is a great one stop solution.

Sent from my HTC Sensation using Tapatalk


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## H3LVTCA (Oct 27, 2004)

Added some BFI engine/transmission mounts last month - they're awesome! 

I'm finally considering upgrading the intake and the intake manifold. 
Who around here has experience with the Neuspeed P-Flo? 
How many manifolds are on the market now?


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## thygreyt (Jun 7, 2009)

H3LVTCA said:


> Added some BFI engine/transmission mounts last month - they're awesome!
> 
> I'm finally considering upgrading the intake and the intake manifold.
> Who around here has experience with the Neuspeed P-Flo?
> How many manifolds are on the market now?


 i had a neuspeed p-flow! :wave: 

same 2: UM and C2


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## H3LVTCA (Oct 27, 2004)

thygreyt said:


> i had a neuspeed p-flow! :wave:


For intakes, is it still Evoms>Eurosport>Neuspeed>Carbonio?


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## thygreyt (Jun 7, 2009)

idk.. they are all the same, sorta. 

if you are going with an intake mani, then dont buy any intake at all!


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## vwluger22 (Jan 25, 2005)

There is also BSH cai intake but depending on which SRI you get a intake could be a waste of money.:beer:


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## H3LVTCA (Oct 27, 2004)

I don't like the BSH intake. Personally it worries me when the instructions to install a product describe the first few steps as "uncoil and cut into the MAF wiring loom".

I'd like to have an intake manifold at some point.
Integrated Engineering seems to be working on a lot of great things for the 2.5L. Maybe I'll hold out until they drop their intake manifold. Seeing how the 1.8T manifolds turned out, I can only hope that the 2.5L ones they're developing are just as great.


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## vwluger22 (Jan 25, 2005)

H3LVTCA said:


> I don't like the BSH intake. Personally it worries me when the instructions to install a product describe the first few steps as "uncoil and cut into the MAF wiring loom".


You aren't cutting any wires you are just removing a little bit of tape around them and then re wrapping them.


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## H3LVTCA (Oct 27, 2004)

Finally got around to compiling footage and editing an Autocross run that I did back in June.
The angles are pretty terrible but the audio is what most folks are looking for.
This video was prior to me installing the Stage 2 BFI mounts.


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## H3LVTCA (Oct 27, 2004)

One year after I last bumped this thread... this car is now for sale!
Trying to pay off some student loans - look here: http://forums.vwvortex.com/showthread.php?6089947-FEELER-FS-2008-OEM-Rabbit-42k-Chicago/


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