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RPi Headers/Exhaust Manifold: Get Smog?

30K views 156 replies 29 participants last post by  keang24 
#1 ·
After several months of testing, we have came to the conclusion that the factory headers were extremely efficient for bottom, midrange and top end power. The main restriction was from the primary cat. Deleting the primary cat would yield significant gains. Some aftermarket headers show good gains on the top end while compromising low end performance. Our headers solution will allow the use of the factory equal length style tubing, while our cat delete will improve hp through out the power band.

Need to smog? Dont pay someone to remove your aftermarket or modified factory header (15+ hours of labor) just to smog your car. Simple unbolt our v-band clamp, put on your stock cat and drive it to your local smog station.

We are working on a solution for the CEL to NOT turn on while our race pipe is installed. This will require NO ecu reflashes. Yes, NO, nada.

$4299, Header package includes:

- modified header
- RPi race pipe (eliminates the cat)
- modified factory cat (complete bolt on when race pipe is unbolted)

 
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#55 ·
What would be really interesting is if this solution provides better performance than the current aftermarket offerings. I believe it may due to the equal-length setup of the stock header system. I'm not sure how much R&D was done on the other aftermarket header solutions, but none of them are equal-length. Supersprint gets the closest to equal-length and Evosport and RDSport are nearly identical. So, it is my supposition that the current gains being found are simply from primary cat deletion and not necessarily improved design or flow. If this is the case, then coupling the "bitchin" (to quote Eloy) design of the stock header with cat deletion and possibly some software optimization, then we could very well see more than the +/- 25 rwhp increases we are seeing from the current offerings. Waiting patiently.
 
#56 ·
We were fortunate to get some "inside" information about the stock M exhaust. As we tested a good sec 2 and 3 coupled with primary cat delete offers a great balance of performance and sound......that you can live with. Removing the secondary cats will give good performance, if the exhaust system is properly designed but will make the entire system louder.
 
#58 · (Edited)
^^ It isnt about Backpressue, its about high flow exhaust dynamics.. There was a big thread on this. RPi Designs there exhausts to have the proper flow dynamics which makes gains and frees up power (IOW its like they keep the pressure while flowing more)

As for the Price.. I think its Ridiculous.

You want our headers, and for 4 Thousand Dollars, you cut out the cats and put in a Flow Dynamic pipe piece, and justify the cost by saying its R+D. I find that verry hard to believe. Im sure the design took some time, but considering BMW charges 4k for the design of the Header and you 4200 for just a pipe piece replacement, something is not right. Its clear it costs money, but im feeling your adding a Heavy BMW Tax on here (probably because you can and people will pay it, not because figuring out how to straight pipe piece the cats costs you that overall amount)

Its a great solution and one of the best out there, but you guys are raping us on the price for essentially a properly flowing mini "downpipe section piece" thats chopped into our stock headers... was it really that hard to figure out?... Doubtful..but heaven forbid we get a cheap solution to the commonly expensive gains of a header replacement. A full header design for 4k, OK, a simple chopped in piece 4k, No thanks
 
#59 ·
^^ It isnt about Backpressue, its about high flow exhaust dynamics.. There was a big thread on this. RPi Designs there exhausts to have the proper flow dynamics which makes gains and frees up power (IOW its like they keep the pressure while flowing more)

As for the Price.. I think its Ridiculous.

You want our headers, and for 4 Thousand Dollars, you cut out the cats and put in a Flow Dynamic pipe piece, and justify the cost by saying its R+D. I find that verry hard to believe. Im sure the design took some time, but considering BMW charges 4k for the design of the Header and you 4200 for just a pipe piece replacement, something is not right. Its clear it costs money, but im feeling your adding a Heavy BMW Tax on here (probably because you can and people will pay it, not because figuring out how to straight pipe piece the cats costs you that overall amount)

Its a great solution and one of the best out there, but you guys are raping us on the price for essentially a properly flowing mini "downpipe section piece" thats chopped into our stock headers... was it really that hard to figure out?... Doubtful..but heaven forbid we get a cheap solution to the commonly expensive gains of a header replacement. A full header design for 4k, OK, a simple chopped in piece 4k, No thanks
This was discussed earlier. The prices are NOT set in stone as we are trying to find more cost affective ways to make our specially designed flanges. They ARE very expensive to machine ($400 for 2 and each set up will requre 8). That, coupled with labor, etc. gave us the initial ball park price. I can assure EVERYONE, that no one is going to get ripped off. Its not what we are about and there is no BMW tax going on here.
 
#68 · (Edited)
:nono::nono:, take a number and wait in line, my friend :hihi::hihi:

:cheers:

Btw, congrats Eloy. Now, go track the damn parts for my project.grrrrrrrgrrrrrrr

Eloy,

Im ready to put them on my car and do another dyno!! lol

They look really good...

Let me know when you are going to release them for sale and are you going to sell the total solution or use example the stock headers on my car??
 
#65 ·
Nice work!:applause:

I hope observers recognize the total benefit here.

No, the headers are not that glossy and shinny product you see from other aftermarket producers, however, the quality of the material, connectors and performance are the winner here. Equal length tubing (or crimped to balance such). Again, not shinny, but more importantly, effective.

PLUS.....

Stealth from dealer view (unless working directly with exhaust) and easy swap for that routine smog check that eventually will occur OR, fixit ticket for sound, etc.

Good luck with this product, another winner!
:cheers:
 
#70 ·
Once you see the fit, finish and machines parts, you might start to understand the pricing and all the work that has to be done to make this conversion. Its NOt simply a hacked cat and a pipe welded on. The reason it takes so long is that swapping the headers is a big job and we have to keep doing it again and again while testing to see which is the best way to make our race pipe. Patience is the key and when its all done and ready to go, you guys wont be dissappointed.

Im still trying to figure out the cost of the total conversion so please hang tight as I will have the final numbers for you guys soon.
 
#71 ·
Once you see the fit, finish and machines parts, you might start to understand the pricing and all the work that has to be done to make this conversion. Its NOt simply a hacked cat and a pipe welded on. The reason it takes so long is that swapping the headers is a big job and we have to keep doing it again and again while testing to see which is the best way to make our race pipe. Patience is the key and when its all done and ready to go, you guys wont be dissappointed.

Im still trying to figure out the cost of the total conversion so please hang tight as I will have the final numbers for you guys soon.
Eloy we are all looking forward to some dyno numbers. Might i suggest that along with getting some DynoDynamics numbers you do some runs on an Dynojet, maybe use SP Engineering. That way you have in house and independant numbers to substantiate your results.

You guys are top notch and if the hp/tq numbers make sense then you have again overtaken the mod market with another AWESOME product!
 
#72 ·
Oh yeah one more question. Are the stock headers coated? Would there be a benefit to doing a Two-Stage Ceramic Coating on the stock headers since you are taking them off anyway??
 
#73 · (Edited)
I ran a dynojet for several years and I can assure you the gains are much more on that dyno than on our dyno dynamics. With that, its not much of a concern to dyno it on a dj. As far as coating the stock headers, thats a possibility but would add to the cost significantly. We are going to dyno the car tomorrow or Friday.

One thing about coating them though, is that its going to be noticable at the dealership. With just the flange in place with the stock cat, the headers still look very stock.
 
#74 ·
#81 · (Edited)
Here is today's dyno. Dynos are as follows:

- stock 386whp
- + ram air 399whp
- headers w/ v1 race pipe 412whp



Im pretty happy with the results considering we are only within 2whp of "other" headers we have tested. Why? Because the hp is similar and our customers will have the option of swapping the stock cats back on. The peak power is great but the amount of midrange power gained is impressive. Now, we are going to bring the transition back 2" and re-dyno the car. If we can pick up another 5whp, I would say, the system is ready for sale. Stay tuned.
 
#84 ·
WOW!:applause:

Did you give time for the ECU to adapt or is that straight install and dyno?

Very nice!:M5thumbs:
:cheers:
exhaust!
Basically installed, ran for 30 minutes on street and freeway, then dyno.

Wow because my car does 414 W/O headers so you are saying I would have a 10hp increase roughly!

Eloy can you also do a run on the Dyno Jet as well if possible I think it will convince more people about the headers as well...
Its not just the peak hp gained. Take a look at the midrange torque gained. Its near 30ft/lbs! The headers will work even better with aftermarket exhaust so you should see some good numbers.
 
#91 ·
Like Brad said, the usable hp/tq from ~5700rpm up to redline looked awsome. It's more constant linear deliverable and pratical than just peak number. I don't need further R&D, I want it as is NOW along with section1/2/3.:thumbsup:
 
#93 ·
Fak! This is going to be awesome. . . .
 
#96 ·
is your vanos problem solved?
 
#94 · (Edited)
Eloy,

With Header pipe, race cats (sec 1) and your ST sec 2 & 3, is it insanely loud? Any drone?

Also, as far as the header pipe conversion is concerned, I do have a couple of questions:

1. Swapping out could be done with just a lift and some tools? About how many hours (minutes) can a muffler shop do the conversion back to stock?
2. Going to the dealership with the race pipe conversion brackets and primaries intact, what kind of warranty-voiding can they forseeably (sp?) do? Since everything is
"techincally" stock except the brackets.
 
#95 ·
No, its not insanely loud. Our full system is one of the quieter ones out there for the very reason or purpose of combining it with our header package. Those who have heard and rode in our car can attest to the little to no drone aspect.

1. The bottom cover has to be removed (not a hard job, just basic tools). Once the cover is taken off, the front part of the exhaust drops as you will have to unbolt the flange and disconnect the exhaust from the race pipe. From the racepipe to the header, there is only a v-band clamp which comes off in seconds. Total time is about 30min to 1 hour.

2. AGAIN, ANY modification to the header WILL void the warrant on your header...PERIOD. Are they going to see it? Most likely not since there is just a flange and clamp towards the top end. If they are doing stuff with that part of the exhaust system then they will see it. All the brackets used for the race pipe are factory.

Although our header solution looks "factory", it was not made or designed to NOT void any warranties from your dealership. The design was made purely for performance and to give people the option of putting the stock cat back on without paying 16 hours in labor.
 
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