So, i installed my Alta R56 downpipe with the borla S exhaust cat back onto my 07 MCS today. I started it up, and it was a great deep sound. I took it off the jacks and drove it and i became disappointed. There was not that much of a gain, it felt like i was driving the MCS how it was before i put in the DP and exhaust. did i do something wrong? and the borla is really droning. i drove it on the freeway and i could barely hear my music. i would have to speed up and get enough speed so i could let off the pedal so i could coast with no drone and sound.

 

Check for an exhaust leak.

besides that not much else.

 

I would not expect to much from exhaust alone. Do the unichip and you will be happy. As for the borla, that's why I got the alta.

 

Bummer, Ya the ALTA system seems to be the best choice for sound and performance. I noticed a gain in power, but it wasnt like day and night. I noticed that the power was created elsewhere in the rpm range. As for the cost to horsepower ratio, its more costly and less effective as say the UNI Chip. I feel my exhaust was purely a cosmetic and sound enhancement, I figure looks an sound is where the value was. Any HP increase is just an added bonus.
As for the lack of power I would assume there has to be a leak. My only suggestion is to backtrack and pay particular attention to the DP.

 

Edited: I have a higher output dyno chart.

Stock:


1st set of TBE runs vs. stock:


Later dyno runs 15whp & 9wtq vs Alta ECU (w/ big gains, esp. in the torque):


The downpipe will definately net you more gains than a catback, so you should see similar gains, even w/ the smaller diameter piping on the Borla. Give it some time for the cats to burn in & the ECU to adjust.

 

I am happy to have had your business! Sorry the butt dyno isn't giving the results you anticipated. But like above, check the connections etc. The other thing might be the diameter of the Borla. Is it less than the 3" like the ALTA?

PLEASE let us know how we can help in anyway further!

 

the borla is 2.5inch piping.

 

No criticism but the OEM plumbing is 2.34" so even with a less restrictive muffler and 2.5" it isn't going to have the same high RPM gains as a 3" system. So you have eliminated the bottle neck at the front, and created one at the rear if that makes sense. Still more HP than stock, but not the same as an all 3" or 3"-4" system.

 

2.5" is not a restriction in any way until 400hp or so.

 

OH K Turbo Expert....

 

now now boys play nice. j/k

 

This is going to be debated till the cows come home.

50% are gonna say 2.5" is not enough, 50% will say 3" is too big for this turbo. Both sides will say they've done enough testing to back up their opinions.

It just so happens I believe the 2.5 crowd...

That is....until a bigger turbo comes my way

 

i'm surprised no one has run a calculation on the piping diameter... Everyone says lower pressure is better after the turbo... For a given volume of air to be moved, the smaller the diameter, the faster the air has to move, and the less pressure there will be. The reverse is the same, wider diameter, more pressure. This is all has bounds though, something way too small will restrict flow too much, something too wide will create crazy turbulence in the exhaust flow and up the pressure.

I'm just guessing, but I bet that 2.5 is the best bet for slightly increased hp with the same turbo. My reasoning behind that I know BMW engineers actually did run calculations, vs. random tune shops that are running on common sense.... no offense to anyone, I'm sure tuners can whip up a dyno to "prove me wrong".

 

Well I think people are applying general turbo principles to all vehicles. So they think 3" would be better. You have to keep in mind this is a 1.6L motor with a pea-shooter turbo...sure maybe if it was a 2.0L a 3" might be of more benefit...like a WRX. Even then, a lot of them are still running 2.5" exhausts.

And sure tuners can give you a dyno to prove you wrong, but the 2.5" crowd will show dynos to try and prove the 3" wrong or vice versa, it will never end. There are certain tuners that I think know their stuff more than others and I will follow them (Partly because they are actual engineers by degree). But hey, not knockin anyone! Put a 4" exhaust on if someone says its good! I'll still keep my 2.5". (Which btw...my new Invidia 2.5" exhaust should arrive tomorrow )

 

^glad to see someone else of the same mindset...

I am an engineer, and took enough classes in mechanical engineering to understand that bigger isn't always better, even with forced induction... Turbulence can seriously up the pressure with fluid flowing through pipes, be it water, air, or exhaust...

 

Did anyone else have a hard time installing the Alta DP? when i was putting it in, the heat shields were a pain in the butt.

 

2.0L WRX = 2.5"
2.5L WRX/STI/LGT/FXT/OBXT = 3"

to say a 1.6L needs a 3" is marketing spin. one of my buddies is running a built STI with 10.5:1 compression, water injection and an SZ55 turbo (huge!). He's running just shy of 500whp on a 3" pipe.

 

Aftermarket Exhaust Shootout !!!

Someone please make it happen!

 

The heat shields are a nightmare! Blame MINI though not me!

 

Also on the plumbing diameter; There are LOTS of good information on plumbing choices outside of the ALTA halls and NAM. Do some google searching and the information will unfold in front of you. Jeff (ALTA2) has also published this in some other similar threads on NAM. When you do the answer is pretty clear.

I do agree in the exhaust shootout and we recently agreed to do one with an independent NAM member and it fell apart simply because of the transmission in his car. (We should use a 6-spd for proper dyno comparability.) I believe one other mfr here on NAM agreed to provide his 2.5" version, we would provide our 3" cat-back. WE hope we can do this soon with a new member of NAM. (For details PM ALTA2 or me.)

Thanks again folks!

 

You will not see any relevant gains until the car is chipped correctly to take care of the ECU. You can put anything you want on a turbo car, until you do an ALTA plug n play or an ECU upgrade, you will be nothing short of disappointed with the small upgrades for such a large cost

 

True that all mods will be better suited with tuning. BUT the results we posted as well as others do NOT require tuning to reap significant results. Turbo charged cars react very well to air flow mods.

Thanks again!

 

Two words: Corky Bell

Figure 11-4, page 133 of "Maximizing Boost".

Chart titled "Approximate exhaust pipe flow area for specific power output".

Corky claims 2.5" is sufficient for a turbo until well over 300HP. Disagree? Take it up with him

Nothing wrong with going as big as you want, though. If the sound of the exhaust at WOT makes you grin uncontrollably, then you have bought the right exhaust

 

well, everybody knows Jeff Perrin at Alta knows more than Corky Bell when it comes to turbo's. Just look at the H6 conversion he did on his STI (and by that I mean the one Jarrad at PDX Tuning built for him)

 

Great, 3" is probably holding back some, tell him to go 3.5", its not something we make, but have him call APS.

Why does the 3" exhaust make more power on the 2.0L?? And cause the turbo to spool quicker on both cars? Who even makes a 2.5" exhaust for the WRX? Long long ago when this turbo car was in its infancy, there were a few guys buying the 2.5" systems, and quickly found the 3" system cars made more power. THen does that mean all the old school eclipse guys are wrong?

I think of the R56 in the same boat as the WRX was in its infancy. There are all these guys new to a turbo car, and the first thing they do is go to books, and read lots of old data, about how to build an exhaust. There isn't really any books that are NEW that talk about turbo cars.

Key word is sufficient, this could be said about any part on the car. Intakes, ehxuast, swaybars, standard oil...

In fact i do disagree. While is far smarter and older than i am, i have seen proof of it. Its interesting how alot of guys on the forum don't quite grasp the 2.5" vs 3" stuff. Its time to just make one and show those who are interested...........

But you even hit the nail on the head, SOUND! A 3" system does nothing but help a turbo car. And a 4" system also could help it out, but SOUND would be horribly loud! Our 3" system would be loud but we picked 2 good mufflers which are not loud, and its nearly perfect sounding. As we have said before, back pressure after the turbo is bad, and WILL for 100% make the turbo spool quicker. Hence more Low end power! This isn't something we are making up.

Maybe Corky will write an updated version, that would hit apon all the new age things. I will buy that book also. You might look a little deeper into when that book was made and the fact that there were not many turbo cars back then and not many guys modding them. Lots of things change in 11years. More people push the limits and prove new things all the time.

Actually, who cares..... If we have a 3" exhaust (which could "potentially" be better than a 2.5" system), and its not loud (according to most customers) and its lighter or very similar weight (than 2.5" systems) and the price is the same or less, then why not buy it? Style, sure, color, sure, i can understand that. If we did market it using a "3 inch bigger is better" (even though, it is) it must be working!

Comments like that really make you seem 15 years younger. I never claim to better than anyone, but we have data to back things up, we do show it. If that makes me come off as all knowing to you, i am sorry.

Whats wrong with doing a fun project like a motor swap, and make 600WHP? Yes it had a 3" exhaust, but it could have used a bigger one and made more power!

Funny how you put that in white so not everyone would see it. You might ask Jarrad if he agrees with that. Jarrad didn't touch my car (no offse to Jarrad).

You are obvously here just to ruin a good thread and try to make me angry. This time it worked! Its funny how when we stand up for something and try to explain things in an educating thread, you bring up the same 2 things to make us angry with, a swaybar and the H6 supposed being built by PDX. Maybe you THINK this because of this pic...




As i have explained before (i think 3 other times on other threads) don't forget, i was one of the people who helped start PDX. Your right "I" put my engine together there, "my" car was there alot, and "I" used their Tig welder (where i learned to weld), some pics were taken at their shop also. The guys there are my friends, and have been for years. So i may have even had a beer there Also funny, i might want to put a PDX on the car and on the engine. I know funny....



There are plenty of customers that can back this up, but obviously you just say things like this to try to make us look bad. Even the swaybar thing that we have explained over and over again. Even though we tried to help you, you still just can't get over your self.


Do i sense some Jealousy, maybe thats your problem.... now go over to your other mini site and spout off about us. Real mature.....