Just installed the Gruppe S headers on my car...

[jigga]

Hey guys,

Last night, I had my mechanic install a set of Gruppe S headers on my car..

As soon as the headers arrived, I had them wrapped with the exhaust wrap. This was to prevent the problems that others have had with unwrapped headers.... consistently missing target boost...

Anyway, installation took my mechanic about an hour and 15 mins. Most of the time was taken up with removing heatshields and removing the stock exxhaust manifold.. The Gruppe S version went on with no problems at all, and since they are wrapped, I am not concerned about the oil filter being in close proximity to the pipes..

Now, I actually took the car for a drive without resetting the ECU. I did this becuase I know that my car was conservatively tuned, so I was not afraid of the car running out of fuel or anything and since I run ECUtek, the ecu will learn on it's own after a few driving cycles.. One of the very reasons I LOVE the ecu reflash... It does it's own tuning

Upon driving the car off boost, the first thing I noticed was that the car is not as 'bassy' as before... It is almost as if someone turned the bass down on the exhaust.. It is just as loud as before, but the engine revs a lot freer than before... almost as if there is a lighter flywheel on the engine.. It is less bassy, and sounds more raw.... The boxer sound we all know and love is DEFINITELY still there, but not as throbby as before

As far as the powerband of the car, I did notice a slight drop in low end torque just off idle. I was expecting this, so I wasn't suprised... Also, there is a drop in torque while off boost.. It isn't anywhere what I would call BAD or anything, so don't let it scare you... It is what I would describe as a 30% difference... If I wasn't on boost, I just noticed that it took a tad bit more throttle to do get the car to pull the way it did while off boost... Please let me reassure anyone who is thinking of getting these headers that it is nowhere as bad as I make it out to be, but since I want to be as thorough as possible, I think it is important that I list everything...

The funny part though is that when my turbo now kicks in at 4000RPMS, the needle damn near bum-rushes the rev limiter! Everything is soo much more lively when on boost. The rev needle just moves much faster when on boost that I now have to keep watchin it if I don't want to hit fuel cut... It is crazy! and scary for me when I first experienced it.. I am not sure how much power I picked up, but I do know that there is a lot more power up there at my car's power peak of 6750 rpms..

There is a reason for this extra liveliness I think... With the ECUtek, and the way boost is setup on it, the ECU is given a "target boost" to reach. Before the header, it would hit 18psi of boost, but now, I am hitting 16psi, with more power while on boost.... The headers reduce the resistance to exhaust gas, so it is almost as if the car is running less boost than before, while making more power... It is hard to explain, but makes sense when you think about it..

Another side effect of installing the header wrap though was a stench that came off it as it was heated by the pipes for the first time.. It smelled like someone baking burned cookies under my hood to be honest. I just drove for a while with the windows down to vent the smell from the cabin, but it is not smoking much anymore.. Must be a 'break-in' thing...

In conclusion, I probably wouldn't get these headers if you are looking for jumps in mid range torque. The stock headers are best for mid range power.. Since from the beginning, my car was meant to shine on the highway, I am not in the least bit disappointed with where I made power (which was in the top end). My car is at stage 4 levels, but with a PE1820 turbo providing boost.. Now, I am sure that the car will get even faster over the next few days as I put a few miles on the new header as the ECU optimises things, so I am looking forwards to the next few days as I regain torque throughout the rev range .. I am making it a point to drive somewhat aggressively just to give the ecu a wider range of parameters to aid the learning process

At my last dyno tune, my car dynoed at a little over 305WHP at 18psi and 94 octane in the tank, so I am not sure where the car's WHP numbers lie right now ..

I have a Perrin FMIC comming for my car next week, so I am going to get more dyno tuning done with boost increased to ~20-21psi with alcohol injection. Hoping for around 340whp, but we'll see!

[PlatinumWRX]

Originally posted by jigga
In conclusion, I probably wouldn't get these headers if you are looking for jumps in mid range torque. The stock headers are best for mid range power.. Since from the beginning, my car was meant to shine on the highway, I am not in the least bit disappointed with where I made power (which was in the top end). My car is at stage 4 levels, but with a PE1820 turbo providing boost.. Now, I am sure that the car will get even faster over the next few days as I put a few miles on the new header as the ECU optimises things, so I am looking forwards to the next few days as I regain torque throughout the rev range .. I am making it a point to drive somewhat aggressively just to give the ecu a wider range of parameters to aid the learning process

I was just discussing headers with a member who runs a stock turbo. Would you say that headers are a mistake with the TD04L?

-Jim

[jigga]

Originally posted by PlatinumWRX
I was just discussing headers with a member who runs a stock turbo. Would you say that headers are a mistake with the TD04L?

-Jim

Umm, whether it is a mistake or not depends on him really... He WILL lose a huge chunk of that midrange 'hit' that the stock turbo is notorious for... It is amazing that I never knew until now about how much a role the stock header plays in that hit we get down low... It is partly because of having such a tiny stock turbo, but it is also because of the headers also... I'd say it is 70-75% turbo, and 25-30% stock headers...

I noticed that additional lag gained by upgrading turbos, but it wasn't until I installed the headers, and I lost what little torque I had left down low that I really noticed how much the stocker helped..

The headers don't add lag by anymeans... It feels like they do because the turbo doesn't hit as had as it does as early as it used to... The turbo still spools up at the same point that it used to with the aftermarket piece, but prior to that spool up point, power is down.. This gives the sensation of lag, when in fact it is a decrease in off boost power...

I probably would not put them on a car with a stock turbo though... The only place they help is in the top end of the rev range (4-7K), with torque losses downlow... Since the stock turbo can't flow the air upstairs anyway, what's the point?? Why take away from where the turbo shines, only to have the turbo fall on it's face on the top end still.....

To those looking to get the headers, I would say to get them last... after a turbo swap and other associated parts...

I think I got my good results because the header and the 1820 compliment each other... Both are good for top end power, and not much else.

[hippy78]

"Before the header, it would hit 18psi of boost, but now, I am hitting 16psi, with more power while on boost.... "

I guess your ecutec doesn't relearn things? On a realistic note, headers can and do improve midrange power especially when coated. By coating headers on the inside(and out) you keep the heat in the pipes, instead of header wrap which keeps the heat in and on the pipes. This will increase the spool of ANY headers or even the stock manifold and give early, quicker spool which that last longer which means more power ealier and longer. I don't think headers are a mistake for the stock turbo, if you get them coated. If you wanna put header wrap on too, that's nice, but coating is much better for the pipes and won't stink every time the pipes get wet. I mean you end up taking about 20 pounds off the car(I don't know the real numbers), and getting boost earlier and longer.

Also, not to rag on you to much jigga, but you have been talkin about how the ecutec learns things that other engine management systems don't. I don't know who told you this, but it is untrue. The stock ecu is the thing that ectually does the learning, and since all aftermarket engine management systems wich are made for the wrx work off the stock ecu, they will all do the exact same thing. fyi..... If you had a utec, you could fix the boost yourself.

The stock headers are not the best for power. I mean maybe on a stock wrx, or one that isn't tuned for aftermarket headers, the stock ones will perform better. Just cause your ecutec is set for the stock headers, and you aren't getting full boost anymore, that does not mean you wouldn't get a lot more power with the headers if you were actually retuned for them. Less backpressure, less load, more power...... Headers are goooooooooooooooooooooood.

peace

[jigga]

Originally posted by hippy78
"Before the header, it would hit 18psi of boost, but now, I am hitting 16psi, with more power while on boost.... "

I guess your ecutec doesn't relearn things? On a realistic note, headers can and do improve midrange power especially when coated. By coating headers on the inside(and out) you keep the heat in the pipes, instead of header wrap which keeps the heat in and on the pipes. This will increase the spool of ANY headers or even the stock manifold and give early, quicker spool which that last longer which means more power ealier and longer. I don't think headers are a mistake for the stock turbo, if you get them coated. If you wanna put header wrap on too, that's nice, but coating is much better for the pipes and won't stink every time the pipes get wet. I mean you end up taking about 20 pounds off the car(I don't know the real numbers), and getting boost earlier and longer.

I have reset my ECU and since then got my 18psi of boost back...

My previous report was without resetting the ECU... all is good and dandy now...

[jigga]

Originally posted by hippy78

Also, not to rag on you to much jigga, but you have been talkin about how the ecutec learns things that other engine management systems don't. I don't know who told you this, but it is untrue. The stock ecu is the thing that ectually does the learning, and since all aftermarket engine management systems wich are made for the wrx work off the stock ecu, they will all do the exact same thing. fyi..... If you had a utec, you could fix the boost yourself.

umm I'm not sure where this is going, but with the UTEC, IT controls what your fuelling and timing settings... not the stock ECU...

The different ECu solutions all arrive at the same goal at the end, but they have very different ways of getting there...

As I mentioned above, after installing the header, by max boost dropped slightly... This was without an ECu reset. After resetting the ECU and going for a drive, I now have a full 18psi of boost, with plenty of passing power.

I HIGHLY doubt that UTEC would recalibrate the boost with just an ECU 'reset'...

The UTEC doesn't learn anything.. It tells the ECU what to do, which is why many people who live in cold climates now have to retune their maps in order to stop their CEL's flashing constantly because of detonation due to colder air temps and winter oxygenated gas......

This was what I was getting at when I spoke about the 'learning' ability of ecu systems out there. I appologise if I did not make myself clear in the other thread.

[hippy78]

umm I'm not sure where this is going, but with the UTEC, IT controls what your fuelling and timing settings... not the stock ECU..

You are incorrect. With the utec, you get to choose what you want. The fueling is done by the ecu, and does it's normal thing with adjusting the fuel trims and what not. The fuel map alters the signal of the maf which changes what the ecu sees. This means it's really just altering the stock ecu's function of fueling a little(just like the ecutec). The ecu is still in control of the fuel, but the utec just tricks it a little.

When not pushing the car, the ecu is in total control of timing. This means the car will run like it was using a stock ecu when not pushing the car. The timing multiplier still exists, and so does the normal ecu fueling(with the fuel trims adjusting everything). When the throttle is pushed down more then 60%, the utec stats using the timing map dependent on load(load is dependant on map pressure). You can also leve the timing settings stock if you want, but the whole purpose of the utec is to be able to tune it the way you want. I don't know who told you this stuff about the utec, but they are wrong.

The UTEC doesn't learn anything.. It tells the ECU what to do, which is why many people who live in cold climates now have to retune their maps in order to stop their CEL's flashing constantly because of detonation due to colder air temps and winter oxygenated gas......

The ecu still learns how much fuel to use the same way the ecutec does while the utec is installed! The utec just adjusts the signal between the maf and the ecu to get it to put out the amount of fuel it wants(just like the ecutec). YOU ARE WRONG. Why won't you listen to me? The temperature got colder for me, with no problems and I have a utec. You are going around saying that you love your ecu more then the utec, but you give reasons which are false cause you don't know anything about the utec. The ecutec is a nice unit, but my point is you shouldn't talk about the utec(especially in a bad way) when you obviously don't know what you're talkin about(no offense).

peace

[jigga]

Originally posted by hippy78
You are incorrect. With the utec, you get to choose what you want. The fueling is done by the ecu, and does it's normal thing with adjusting the fuel trims and what not. The fuel map alters the signal of the maf which changes what the ecu sees. This means it's really just altering the stock ecu's function of fueling a little(just like the ecutec). The ecu is still in control of the fuel, but the utec just tricks it a little.

When not pushing the car, the ecu is in total control of timing. This means the car will run like it was using a stock ecu when not pushing the car. The timing multiplier still exists, and so does the normal ecu fueling(with the fuel trims adjusting everything). When the throttle is pushed down more then 60%, the utec stats using the timing map dependent on load(load is dependant on map pressure). You can also leve the timing settings stock if you want, but the whole purpose of the utec is to be able to tune it the way you want. I don't know who told you this stuff about the utec, but they are wrong.



The ecu still learns how much fuel to use the same way the ecutec does while the utec is installed! The utec just adjusts the signal between the maf and the ecu to get it to put out the amount of fuel it wants(just like the ecutec). YOU ARE WRONG. Why won't you listen to me? The temperature got colder for me, with no problems and I have a utec. You are going around saying that you love your ecu more then the utec, but you give reasons which are false cause you don't know anything about the utec. The ecutec is a nice unit, but my point is you shouldn't talk about the utec(especially in a bad way) when you obviously don't know what you're talkin about(no offense).

peace

For the sake of not arguing, I'll conceed... I am just reporting what I have seen around here.. You can search, and you'll see it too..

Can we take this to pm's? Just tryin to keep the thread on topic

[hippy78]

We could, but I have one more thing to say. You have been part of the contribution to the misinformation about the utec. You say that you have "read" but you really don't know and are still talkin crap about it in 3 different threads. Like I said, I'm glad you love you reflash so much, but that's no reason to talk badly about a product you have never even seen with your own eyes. Back on subject, how does it feel now that you reset the ecu?

peace

[jigga]

Going back to your comment about the headers being good for power, YES! You are correct, they are... but that is in the high end of the rev range where the stock turbo can't flow enough to use the reduced restriction to full effect...

You lose off-boost power with the headers, and make huge gains past 5K rpms, but if the stocker is already useless at those engine speeds, why lose off boost power for a power increase up top that is meager at best? With a bigger turbo that can flow the air up top and take advantage of the reduced restriction,

Even Gruppe S themselves have mentioned that the header would better function as a last thing to do in order to eek out that little bit of power of your setup ie. bigger turbo, exhaust, fuel system, etc.. This is not to say that you won't gain anything on the stock turbo...

As I mentioned in my original response to the question, I think it is a personal choice... it's all about how you like your powerband i guess....

IMO though, it is not something I would recommend on a stock turbo since it takes away from where the stocker shines the most...

If the stock turbo was a top-ender, I would GLADLY recommend it, but that is just me.. Your milage WILL vary

[hippy78]

I disagree, and was just wondering where you got your data of the off boost power loss with aftermarket headers? If it's from the feeling you got today after resetting the ecu, maybe you should wait a week til the timing multiplier goes up to form a conclusion? eh, at least ya stopped sayin that bs about the utec.......

[happasaiyan]

always gotta argue for the sake of arguing, dont you hippy. he already said you win and has moved on past that, but you still keep throwing it in his face. i wouldnt have been as patient as him...

[jigga]

Originally posted by hippy78
I disagree, and was just wondering where you got your data of the off boost power loss with aftermarket headers? If it's from the feeling you got today after resetting the ecu, maybe you should wait a week til the timing multiplier goes up to form a conclusion? eh, at least ya stopped sayin that bs about the utec.......

ahh... I sent you a pm about the whole utec thing...


As for waiting a week for the timing multiplier to go up, there is no need... Check for Vishnu's trick for getting the multiplier back up in less than 5 minutes...

As far as data supporting a loss in off boost power with the headers, I'll suggest that you perform a serch on NASIOC for some plots..Most of what people have said about aftermarket 4-1 headers with regards to power distribution is in fact true...

[BoostedBoxer]

good write up Jigga, i am considering getting some of these.

Please stay on topic, as this is a good write up and i hate to see it deleted.

[jigga]

Originally posted by BoostedBoxer
good write up Jigga, i am considering getting some of these.

Please stay on topic, as this is a good write up and i hate to see it deleted.

Thanks for the props, I just put the write up on just to try to answer a few of the questions that I myself had about the headers but had no answer on..

Hippy, I cannot give you any hard data as to how much low-end power was lost. I have a Perrin FMIC turning up next week, and after I have that installed, I will be getting a dyno tune. I really don't feel it necessary to pay right now in order to confirm with numbers what I already notice upon driving the car in and around town.

I can tell you though that it required more throttle input than before to get the car to move the way it used to while off boost. Also, the car doen't roll off the line with the same authority as it did before. It requires a few more revs in order to get it to move as it did. While on boost though, it is the opposite. The power just fluidly comes rushing on, and the rev needle is much quicker on it's way to the fuel cut than it was before...
These are qualitative aspects of the header install that I doubt would sho up on a dyno, but it IS there none the less..