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Borla Exhaust Manifold/Header For RX8
Borla exhaust is in the process of designing a high performance header/exhaust manifold for the RX8. Due to the input of the members and moderators of this forum, our cat-back has been a success and we are hoping to continue this with our header. If you have any ideas and/or input you can give us while we are in the design phase of this header for the RX8 it will be greatly appreciated. Thanks for your help
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I'm definitely interested in the header that you're developing. I e-mailed your company in reference to my interests, but never heard back from anyone. Glad to hear your'e going to have a unit available.
I already have a Borla cat-back and so far very satisfied. |
Originally posted by mdw33333 I'm definitely interested in the header that you're developing. I e-mailed your company in reference to my interests, but never heard back from anyone. Glad to hear your'e going to have a unit available. I already have a Borla cat-back and so far very satisfied. |
Glad to hear you are working on this David. I too have the Borla cat back system, and couldn't be happier with it! I've been singing the praises of this system ever since I got it.
With regards to the header, I've heard that due to the angle of the exhaust ports of the Renesis engine, a header yields minimal gains. Is this your experience? Please be sure to share with us dyno charts as soon as you have them, like you did with the cat back exhaust. Also, I'd be interested to know your targeted price for this header. And finally, I would suggest you offer this header with more of a utilitarian finish rather than anything fancy like crome, to keep the cost down. The exhaust manifold is all but invisible in the RX-8, and I for one would not want to pay extra to make the header pretty. |
Originally posted by Omicron Glad to hear you are working on this David. I too have the Borla cat back system, and couldn't be happier with it! I've been singing the praises of this system ever since I got it. With regards to the header, I've heard that due to the angle of the exhaust ports of the Renesis engine, a header yields minimal gains. Is this your experience? Please be sure to share with us dyno charts as soon as you have them, like you did with the cat back exhaust. Also, I'd be interested to know your targeted price for this header. And finally, I would suggest you offer this header with more of a utilitarian finish rather than anything fancy like crome, to keep the cost down. The exhaust manifold is all but invisible in the RX-8, and I for one would not want to pay extra to make the header pretty. I will certainly share the dyno results with you guys as soon as we have them. Not sure about a target price since we haven't even seen the OEM piece yet. Do you have a ballpark idea of what the right price might be? We never polish our production headers. Borla is a performance oriented manufacturer and polishing adds no performance value to the part, it only greatly increases the price. However, we have found that in certain circumstances ceramic coating has a great performance value, especially with headers so there is a good chance that we will only offer this header as a ceramic coated piece. On another note, I am amazed that enthusiasts pay for polished exhaust products. Especially those that will buy a cat-back with alumized mild steel piping and a polished muffler over a cat-back that is 100% stainless but unpolished. The polishing wears off fast but the stainless steel lasts a million miles. Thanks again for your input. |
Due to the siamesed center exhaust ports I would personally take a different approach to header design. Unortunately since each chamber's exhaust interact at the engine and then farther down the path as the outer ports join in I would think that an equal length header would give minimal gains. Looking back at old engines from decades past I would be more inclined to try a deadleg pipe on the center port to give an organ pipe resonance tuning. I would collect the 2 outer ports at a certain distance (don't know how far since I haven't tried it) but not join in the center port here. I would add it in farther down stream at a ratio in length with the first pipes of 3/4. In other words if the outer pipes collected at 15" I'd add in the center port at 20" total length or 5" downstream from the first collector. Then I'd add a deadend pipe straight off of the center port as close to the engine as possible with a length of 15" and blocked off at the end. I feel that this design has some merit and is definitely worth study on the Renesis due to the siamesed center port needing special attention. The hard part is finding a way to fit this into the car but I believe it can be done. The numbers I used are for example only. I do not know the exact lengths needed but the ratios are the same. A design similar to this picture:
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This is great. Thanks.
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What is truly GREAT is having vendors actually asking us, the user base, for our input!
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Hey David, If you try my manifold design idea out and find that it works do I get the first production piece free! ;)
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Originally posted by Omicron What is truly GREAT is having vendors actually asking us, the user base, for our input! |
I would be interested in purchasing this if the dyno results show a performance gain.
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Originally posted by rotarygod Hey David, If you try my manifold design idea out and find that it works do I get the first production piece free! ;) |
Actually it is a race header design from back when it was common to have the 2 center exhausts from a 4 cylinder engine siamesed in the block so that there were only 3 ports. Made no sense to me but the ways around it were very creative. An option very similar to this is to not use a deadleg pipe but rather increase the length of the center port so a ratio of 1/3 is used. the primaries collect at 1/3 the total distance to the center pipe collection point. that would be hard to squeeze in the car. I can't take credit for the initial design but maybe in trying to use it on a rotary though. If it works you heard it here first. If it doesn't, it was Wakeech's idea!!! ;) j/k
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Ive seen many "coming soon" headers in r&d and they havent seemed to make it to production.Not sure if the design used didnt yield the hp they were looking for or not.Dave if you come up with something id buy it.
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If this can get a CARB exemption and make a decent gain, I'll buy!
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Im in with the rest
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What is your thoughts to the emissions pipe that is plugged into the top of the header. Would this be better plugged for better performance gains. If you bought a header would you want to get rid of this or plug it back in to the aftermarket header. After tracing where it goes it looks like it meets up to maybe an electronic air pump for emission purposes.
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If the car needs to funcion properly in respect to the ecu not sending an error code, the pipe needs to be integrated back in. If not, block it off.
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David Borla -
Here's something you might find interesting: Originally posted by RX-8 friend in this thread. Exhaust - (yeah, I know, this thread is OTHER than intake and exhaust) - BUT, no-one has considered 2-stroke technology. Yes, the rotary including the renesis is "4 stroke", but really it's a "continuous combustion" engine. There are no "strokes". Many people like to compare it to a 2-stroke, but it's similar only because it is "piston ported" (rotor ported). Now, in a 2-stroke engine, to extract "unreal" power (how about 150+ HP from a 500 cc), we use the exhaust pulses to suck the exhaust out and force charge the combustion chambers. This is not possible with a turbo (it blocks or interferres with the pressure waves). With a NA however, it is possible. What you do is put in a pipe feeding a resonant chamber just after the exhaust port. The end of the chamber is shaped to reflect the exhaust pulses such that the pulse exiting the engine lasts long enough to suck fresh intake charge into the exhaust system, and when the pulse wave reflects back it shoves this extra charge back into the exhaust port. This requires one to design the porting and the exhaust as one system. Yes, it will start to sound even more like a "weedeater", and yes, it will almost double the engine output (if the internals can stand that level of power). Oh, and yes, fuel economy means you can get from one gas station to the next ;) Something I've always wanted to try, being a 2-stroke M/C fan. I think I've got Maurice enticed (he also is familiar with 2-stroke tech). Maybe sometime later this year.... |
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