MRF X-Pipe - 24 HP/18 TQ gains OVER the Akra Evo?!? Something's in the Kool-Aid

[aus]

Now someone needs to dyno this X-pipe on a FBO car vs. an Evo.

[esquire]

Originally Posted by aus

Now someone needs to dyno this X-pipe on a FBO car vs. an Evo.

I can tell you that malek@MRF's car is just his velaforza exhaust and tune and he's putting down a little over 400hp to the wheels.

[Richbot]

Boost drop is a clear indicator the akra was more restrictive, dead giveaway on a supercharged car.

[slicer]

Originally Posted by Chriskm3

Guys. Comparing catted vs catless xpipe is not fair game. Akra will pass emmisons where catless will not.

Akra will not pass emissions in CA. Not sure about other states.

[Jbook]

I wonder what the difference would be with AA HFC x-pipe vs the Akra Evo HFC x-pipe given the AA HFCs are positioned as primaries and the Akra HFCs are positioned as secondaries.

[rjd598]

Originally Posted by esquire

I mean if people start clamoring for this exhaust he'd be making a mistake if he didn't.

And at the price he's charging, I fully expect people to be lining up.

exactly. i remember i pm'ed him awhile back and was curious what they went for. he charged a very fair price for what was being offered imo

[Richbot]

Originally Posted by Jbook

I wonder what the difference would be with AA HFC x-pipe vs the Akra Evo HFC x-pipe given the AA HFCs are positioned as primaries and the Akra HFCs are positioned as secondaries.

Usually the further downstream the restriction, the lower the impact on peak power, would be a good same day/dyno/car test

[Longboarder]

Originally Posted by esquire

I can tell you that malek@MRF's car is just his velaforza exhaust and tune and he's putting down a little over 400hp to the wheels.

This is what did it for me - check out the dyno from an otherwise bone stock m3 with and without the MRF exhaust. When I was trying to figure out which exhaust combo to go with, it wasn't just about peak power (although that was an important consideration). Even with the 625 supercharger, I still felt that the car lacked mid-range punch. The MRF did it's job and gave me a bunch of mid-range to balance it out. What is crazy is the almost 50 RWTQ increase over stock on an NA car at 5K RPM. That is insane!

http://www.mrfengineering.com/wp-con...-velaforza.jpg

Oh yeah, after going for a ride in Malek's car I was like WTF this thing is so visceral and fast as hell. It felt WAAAAAAYYYYY faster than my stock M3. Other than the full MRF exhaust I think it also has a tune but nothing else.

[Jbook]

Originally Posted by Richbot

Usually the further downstream the restriction, the lower the impact on peak power, would be a good same day/dyno/car test

I dunno why I said that, I actually did dyno same day with an e93 also with ESS 625 and he had the Akra Evo. Both of us had 20" wheels at the time and our HP numbers were pretty even, but my car was making significantly less torque... I'm having my car checked for boost leaks today and also replacing the belt tensioner as the belt is slipping at higher RPM shifts.

Regardless, I've since switched to 19" BBS FI and will be going catless to see if the gains are worth the rasp and smell.

[esquire]

Originally Posted by GOLFFRR

what about the weight difference between the two?

I believe the MRF unit is within 1 pound of the Akra Unit - it might even be lighter. Malek@MRF will be in a better position to give a precise answer. Either way, the weights are very close, which I think will surprise a lot of people.

[elim11]

Nice write up esquire. That is a huge surprise, since many people consider Akra to be the gold standard. Enjoy your new-found power!

I am interested to see the technical reasoning behind this. Hopefully Malek can chime in.

[Jive]

That is stunning. Could it be because the HFC on the Akra are somewhat restrictive on a FI set up? Perhaps the real test should be Gintani catless X-pipe vs Akra GT4 X-pipe vs MRF catless X-pipe.

Enjoy your new found gains! I suspect a resurgence in demand for this mythical unicorn X-pipe.

[esquire]

Originally Posted by FormulaMMM

Crazy results. My impression was that there were negligible gains to be had catless over Akra mid (or high flow equivalent), and dyno tests confirmed as much. Guess they were using the wrong catless x pipes for comparison testing?

That's my understanding as well - namely that High flow (100 Cel) cats have minimal impact on power/torque, and certainly not a 30 HP/ 26 TQ worth of impact.

Originally Posted by Richbot

Boost drop is a clear indicator the akra was more restrictive, dead giveaway on a supercharged car.

Agreed. Boost is in part a function of volumetric efficiency. More restriction means higher boost, and vice versa.

Originally Posted by rjd598

exactly. i remember i pm'ed him awhile back and was curious what they went for. he charged a very fair price for what was being offered imo

Yeah. MRF is charging considerably less than for its X-pipe and full exhaust than the Akra Units. By a large margin. Made my decision to pull the trigger pretty easy actually.

Originally Posted by Longboarder

This is what did it for me - check out the dyno from an otherwise bone stock m3 with and without the MRF exhaust. When I was trying to figure out which exhaust combo to go with, it wasn't just about peak power (although that was an important consideration). Even with the 625 supercharger, I still felt that the car lacked mid-range punch. The MRF did it's job and gave me a bunch of mid-range to balance it out. What is crazy is the almost 50 RWTQ increase over stock on an NA car at 5K RPM. That is insane!

http://www.mrfengineering.com/wp-con...-velaforza.jpg

Oh yeah, after going for a ride in Malek's car I was like WTF this thing is so visceral and fast as hell. It felt WAAAAAAYYYYY faster than my stock M3. Other than the full MRF exhaust I think it also has a tune but nothing else.

Holy Sh**. That ~50 TQ delta over OEM is insane. And yeah, Malek's car is easily the fastest non-supercharged M3 i've been in, and he doesn't even have pulleys or air intake. Just the Velaforza Exhaust and tune. Thing is nuts. It pulls like a friggin freight train.

Originally Posted by elim11

Nice write up esquire. That is a huge surprise, since many people consider Akra to be the gold standard. Enjoy your new-found power!

I am interested to see the technical reasoning behind this. Hopefully Malek can chime in.

Thanks. I've been enjoying the power so much. The car is so much fun to drive now. And yeah, I think Malek@MRF is in a better position to comment on the technical aspects of this X-pipe. Hopefully he chimes in soon.

Originally Posted by Jive

That is stunning. Could it be because the HFC on the Akra are somewhat restrictive on a FI set up? Perhaps the real test should be Gintani catless X-pipe vs Akra GT4 X-pipe vs MRF catless X-pipe.

Enjoy your new found gains! I suspect a resurgence in demand for this mythical unicorn X-pipe.

That would be an interesting test. My understanding is that the regular Akra actually puts down more HP than the Akra GT4 in supercharged applications - though that sounds counter-intuitive to me. Like Longboarder said, EAS has observed that the regular Akra is, generally speaking, putting down the best numbers on supercharged cars.

I wish people could feel how insane fast this car is now compared to how it was before. Its seriously ferocious. The fact that the car is getting to 575 on 91 octane... I'm thinking I might have a chance of hitting 600 Hp to the wheels on 95 octane.

[aus]

Anyone have a pic of this uberX-pipe??

[flipm3]

Originally Posted by aus

Anyone have a pic of this uberX-pipe??

From a For Sale Thread here on the forums

[OCKlasse]

I call Photoshop.

-Brandon

[pbonsalb]

He has the X located further forward than on some x-pipes. From what I understand, the X should be located close to the end of the headers, but the transmission usually gets in the way on V8s. I think RPI also puts the X further forward than most x-pipes.

The X may be more carefully welded in the X section and that could help the balance of flow. Some of the X-pipes using longer curved sections for the X do not allow the builder access to the inside mating surfaces to make sure they fit well.

The rest is 2.5 inch pipe, and 2.5 inch pipe is 2.5 inch pipe.

[Black Gold]

Originally Posted by Chriskm3

Guys. Comparing catted vs catless xpipe is not fair game. Akra will pass emmisons where catless will not

Untrue actually. Akra has no primary cats, so it will not pass emissions.

So as far as emissions go, catless and akra are identical since neither have cats between the primary and secondary o2 sensors.

[BPMSport]

Originally Posted by KennyPowers

Untrue actually. Akra has no primary cats, so it will not pass emissions.

So as far as emissions go, catless and akra are identical since neither have cats between the primary and secondary o2 sensors.

My Akra has 2 100 cel HFC's

Only the Akra GT4 is Catless.

[Black Gold]

Originally Posted by Mike Benvo

My Akra has 2 100 cel HFC's

Only the Akra GT4 is Catless.

Not between the o2 sensors.

The akra has cats further downstream which has no affect on emissions testing since they are after the secondary o2s

[Chriskm3]

Originally Posted by KennyPowers

Untrue actually. Akra has no primary cats, so it will not pass emissions.

So as far as emissions go, catless and akra are identical since neither have cats between the primary and secondary o2 sensors.

Very true. Thanks

[IMG]

Very nice gains