Bridged + Tuned =Loving It!
06-21-2012, 07:28 PM
#51
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06-22-2012, 01:06 AM
#53
I think it's clear that there could be a number of reasons why the ports aren't the limiting factor and it doesn't surprise me that the ports are capable of flowing enough air for more hp.
06-22-2012, 08:57 PM
#54
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The reason rotary builders keep things mum about what they do when building/modifying engines (at least in my own case, anyway) is not a concern for quality but moreso because the rotary engine lacks many things that piston engines have. As such, there is little opportunity for us to differentiate ourselves from one another and we prefer to keep our methodologies to ourselves.
But that's different from somebody claiming their engine builder came up with the holy grail of methods without providing evidence to support the claim
06-23-2012, 11:40 AM
#55
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In a community as passionate, well-informed, and quirky as rotary enthusiasts are, there has been nothing offered as evidence/proof which has settled debates on anything around here......... nor should there be. Any documentation offered can be altered to present a desired outcome. Any claims can be explained in a way so as to sound plausible. Anyone who has spent enough money can be convinced there was some sort of benefit derived from their expenditure.
As for which approach to any situation is the best; I would opine that the only one capable of making that decision is the individual.
As for which approach to any situation is the best; I would opine that the only one capable of making that decision is the individual.
So let me put it this way instead. I guess it would be 'fair' for some people making big claims about anything to offer 'some' sort of evidence, not to settle the matter once and for all, but to add a degree of credibility to the argument.
Last edited by pistonhater; 06-23-2012 at 09:38 PM.
06-27-2012, 10:10 AM
#57
One metric seldom discussed here would be drag strip runs. Elapsed times are sensitive to driver technique, but final speeds much less so. Rather than spending a pile of cash on dyno hours, I'm looking now more toward finding open drag nights to work on my tuning.
06-28-2012, 08:23 AM
#58
The Prototype
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In the context of this specific thread, I would like to offer my own opinions if I may;
1) MazdaManiac can say what he wants about this particular engine and it's airflow characteristics but his measuring abilities are nowhere near what they need to be to make such observations with credibility. His own discussions in the past on this forum as regards the MAF sensor, the PCM, and the nature of his work indicate as much. Without the proper air meter and an engine dyno, any alleged airflow "improvements" are merely speculative and subjective.
2) Evaluating a given rotary engine's performance based primarily on the nature of the "brap" is also nonsense. Disrupted idle airflow, ESPECIALLY with the Renesis, is in no way indicative of the torque output across the RPM band. Such idling characteristics in modern engines is actually unnecessary with proper set up and tuning, and the flattest, widest, highest torque band is what all OEM engineers are striving for when designing any given engine. As such, just like with so many other things automotive enthusiasts and hobbyists do with their own cars, it seems we have here yet another modification of an engine that has, most likely, undone a lot of research and engineering that mazda pout into this engine. With the Renesis, Mazda attempted to squeeze a little more life out of an engine that was having a difficult time remaining relevant in an age of impressive airflow engineering as rotary engines are notoriously inefficient at converting gasoline into motive energy.
3) The location of the pinholes in the ports is quite likely to actually REDUCE airflow at various points in the RPM range. See "The Bernoulli Effect" for a brief example of my concern.
4) The reason rotary builders keep things mum about what they do when building/modifying engines (at least in my own case, anyway) is not a concern for quality but moreso because the rotary engine lacks many things that piston engines have. As such, there is little opportunity for us to differentiate ourselves from one another and we prefer to keep our methodologies to ourselves. In BHR's case, our customers receive a log of all their engine's clearances after I am finished building their engines. Further, whenever we present our work to the public we far more often experience a bunch of criticism form internet "know-it-alls", "armchair quarterbacking", and/or claims from others that they would have done it differently or could have done it better. Those of us who perform these services for our livings already know who the good builders are and who the questionable builders are and most of us are way too busy to be critical of one another's work.
5) To say that $7,000 was spent on an engine build and that another car was faster is an unfair comparison. I have no idea who it was that charged that much to perform an engine build (mighta been one of my engines for all I know) but the only thing we rotary builders can do is use parts that are suitable for use, clearance the engine parts properly, and assemble everything properly. Whatever power the engine makes after that is dependent on many other factors which are often out of the builder's control.
1) MazdaManiac can say what he wants about this particular engine and it's airflow characteristics but his measuring abilities are nowhere near what they need to be to make such observations with credibility. His own discussions in the past on this forum as regards the MAF sensor, the PCM, and the nature of his work indicate as much. Without the proper air meter and an engine dyno, any alleged airflow "improvements" are merely speculative and subjective.
2) Evaluating a given rotary engine's performance based primarily on the nature of the "brap" is also nonsense. Disrupted idle airflow, ESPECIALLY with the Renesis, is in no way indicative of the torque output across the RPM band. Such idling characteristics in modern engines is actually unnecessary with proper set up and tuning, and the flattest, widest, highest torque band is what all OEM engineers are striving for when designing any given engine. As such, just like with so many other things automotive enthusiasts and hobbyists do with their own cars, it seems we have here yet another modification of an engine that has, most likely, undone a lot of research and engineering that mazda pout into this engine. With the Renesis, Mazda attempted to squeeze a little more life out of an engine that was having a difficult time remaining relevant in an age of impressive airflow engineering as rotary engines are notoriously inefficient at converting gasoline into motive energy.
3) The location of the pinholes in the ports is quite likely to actually REDUCE airflow at various points in the RPM range. See "The Bernoulli Effect" for a brief example of my concern.
4) The reason rotary builders keep things mum about what they do when building/modifying engines (at least in my own case, anyway) is not a concern for quality but moreso because the rotary engine lacks many things that piston engines have. As such, there is little opportunity for us to differentiate ourselves from one another and we prefer to keep our methodologies to ourselves. In BHR's case, our customers receive a log of all their engine's clearances after I am finished building their engines. Further, whenever we present our work to the public we far more often experience a bunch of criticism form internet "know-it-alls", "armchair quarterbacking", and/or claims from others that they would have done it differently or could have done it better. Those of us who perform these services for our livings already know who the good builders are and who the questionable builders are and most of us are way too busy to be critical of one another's work.
5) To say that $7,000 was spent on an engine build and that another car was faster is an unfair comparison. I have no idea who it was that charged that much to perform an engine build (mighta been one of my engines for all I know) but the only thing we rotary builders can do is use parts that are suitable for use, clearance the engine parts properly, and assemble everything properly. Whatever power the engine makes after that is dependent on many other factors which are often out of the builder's control.
I understand there is bad blood between you and Jeff. That is fine and none of my business. All I can say his tuning got my car to what it is today.
Comparing that sad 7000 rebuild to my car is fair. Especially when you switch cars and drivers and my car still pulls ahead with the other driver. Also I have perfomed this other test on 3 other stock healthy RX-8's and the other drivers in my 8 surpassed me in there own cars. If there isn't truth that those ports and tuning didn't make a difference then I don't know what to tell you. I agree the dyno will tell the complete story.
And no it wasn't you who built the motor, but a shop in the mid west. I won't be that cruel and put there name out there like that. But it was a little shocking when the owner told me because this shop suppose to be well seasoned with street rotary and race rotary builds. I feel like everybody has a "Monday " moment and I think they had that moment on this persons motor. So I didn't feel the need to put them out there like that, but it did take me back some.
06-28-2012, 08:39 AM
#60
The Prototype
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06-29-2012, 09:47 AM
#63
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My comment had nothing to do with any alleged "bad blood" between Jeff and myself. It had to do with technical matters, only, and Jeff's own opinions as posted elsewhere on this forum.
What do you suppose it might be with that $7,000 engine that is causing it to underperform to your specs? What are we builders supposed to do to guarantee power output with our builds after we have (assumedly) properly determined which parts to re-use, properly clearanced the individual parts, and properly assembled everything according to the service manual? I am not trying to be argumentative nor controversial; I ask these questions because I am always curious as to the path of logic people take when developing their opinions about things.
What do you suppose it might be with that $7,000 engine that is causing it to underperform to your specs? What are we builders supposed to do to guarantee power output with our builds after we have (assumedly) properly determined which parts to re-use, properly clearanced the individual parts, and properly assembled everything according to the service manual? I am not trying to be argumentative nor controversial; I ask these questions because I am always curious as to the path of logic people take when developing their opinions about things.
I just feel bad for the owner shelling out 7k bucks and getting less than stellar results. I agree that builders as yourself really can't gaurantee power output numbers. Like my builder explained to me, you can build rotary motor A , build rotary motor B , uses the exact same parts,new housings, intermediates, and rotary motor A may have 5 more HP than rotary motor B , then rotary motor B may have 5 more torque than rotary motor A. Yet the two motors was built the exact same way , same parts, etc.
For my motor, I will be happy if I make more than 1 hp over the across the board number of 185 whp that the majority of RX-8 make I know there are a few factory spec cars that make close to 200, but those cars are few and far between. I am not expecting much just looking for real progress. Anything lower than that and I will be some what dissapointed, even though I highly doubt that I am making less than a stock RX-8. I am very open minded with the route I chose, as it didn't cost me extra to have what was done , like my builder said we're already there with the motor open,so why not go forth with the ports.
So I called again for a dyno quote, that 180 -220 was for tuning. Its 110 to pull 3 runs....a little better but still expensive.
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