World's first FT86 Anti-Reversion,(A/R) Header

[s2d4]

Originally Posted by KoolBRZ

I don't mind crossing the river, (Columbia) to Portland for a dyno, but going all the way to Minneapolis for Grimmspeed never crossed my mind. That's like driving all the way across Australia, for you Aussies.
Wryann from VIP Performance at least owns a daily-driven FRS, which he races. He's willing to give me a break on prices. I'm not sure if I'll have to take it home to swap headers though. Since I use an OpenFlash Tablet for tuning, I can switch between 5 stored tunes for each header, 6 if I reload the stock ROM, so that may be my new testing protocol.

No, as in convince them that it is feasible, they may take care of the rest if they believe it enough to incorporate these and make some headers. Look at the amount of testing they do for their parts.

[KoolBRZ]

Originally Posted by s2d4

No, as in convince them that it is feasible, they may take care of the rest if they believe it enough to incorporate these and make some headers. Look at the amount of testing they do for their parts.

And you know what it takes to convince them? Test results, that's what. So I still need to dyno the headers to prove whether or not there is a positive difference, not a negative one for the inserts. After all, the Harley dyno tests showed negative results. I might have made a big mistake modifying my header, so dyno tests will let me know. I figure dyno tests with multiple tunes should show me the clear difference I'm looking for.

[FirestormFRS]

Keep on believing boys!

http://www.nrhsperformance.com/tech_arcones.shtml

[s2d4]

Originally Posted by FirestormFRS

Keep on believing boys!

http://www.nrhsperformance.com/tech_arcones.shtml

Pretty sure it's just the one guy.

[Malt]

Originally Posted by KoolBRZ

And you know what it takes to convince them? Test results, that's what. So I still need to dyno the headers to prove whether or not there is a positive difference, not a negative one for the inserts. After all, the Harley dyno tests showed negative results. I might have made a big mistake modifying my header, so dyno tests will let me know. I figure dyno tests with multiple tunes should show me the clear difference I'm looking for.

Frankly the fact that you are considering dyno testing all the setups is a huge positive but you need to be careful in not biasing the results. Obviously a stock header with a stage 1 tune is going to under perform a catless header with a stage 2 tune. What this will provide is a baseline for the expected performance increase compared to your modified header.

Like the others have said, it takes time for the ECU to completely learn trims (its longer than 15 miles) and I don't think its feasible to test all three scenarios in one day while giving the ECU time to learn trims and not be ridiculously expensive from a dyno rental standpoint. This may lead to different weather conditions which affect the results which can be accounted for on the dyno but its not ideal.

Either way you have a lot of skeptics here for good reason. The theory behind this mod doesn't sound like it has merit but I've been wrong in the past. Just be careful that you don't end up biasing the test results in order to get results that line up with what you want which doesn't serve any purpose other than "proving" you were right.

[KoolBRZ]

Originally Posted by Malt

Frankly the fact that you are considering dyno testing all the setups is a huge positive but you need to be careful in not biasing the results. Obviously a stock header with a stage 1 tune is going to under perform a catless header with a stage 2 tune. What this will provide is a baseline for the expected performance increase compared to your modified header.

Like the others have said, it takes time for the ECU to completely learn trims (its longer than 15 miles) and I don't think its feasible to test all three scenarios in one day while giving the ECU time to learn trims and not be ridiculously expensive from a dyno rental standpoint. This may lead to different weather conditions which affect the results which can be accounted for on the dyno but its not ideal.

Either way you have a lot of skeptics here for good reason. The theory behind this mod doesn't sound like it has merit but I've been wrong in the past. Just be careful that you don't end up biasing the test results in order to get results that line up with what you want which doesn't serve any purpose other than "proving" you were right.

I'm not just testing modified versus stock header. I just bought another "BRZ 13-UP TOP SPEED PRO-1 Performance Header Straight Flex Pipe" header, which I will be testing to determine if my modifications, (of the same exact header) have a positive or negative influence. Using multiple tunes without allowing ECU adaptation means they won't perform their best, but should show where the headers differ. some tunes are leaner than others, some have more timing, and some have VVTI changes. I'm just looking for positive or negative differences, not how much change there is. If nothing else, I know the inserts have changed the tone for the better. It has a nice baritone rumble now, not raspy at all, yet nice and quiet while idling or cruising. I was checking the differences with Romraider's compare feature, and surprised to find significant differences between EL and UEL tunes. I'm currently running the stage 2 91 Oct UEL tune, and I think I like it better. It seems more civilized in tone, and more quietly torquey at low RPM's.

[Smoke Destructer]

Wait, are you running an UEL tune with EL headers?

[raven1231]

Originally Posted by Smoke Destructer

Wait, are you running an UEL tune with EL headers?

He has the cones BRO

[KoolBRZ]

What, no jokes about conehead(ers)s? They come from......France! That's right. We come from France. (Google Coneheads)
Yes, I am running a UEL tune on an EL header. I watch my readings on my OFT, so I know it's not hurting my engine. It definitely runs different though. Heh, heh, always question, always try something new.

[Poodles]

[Hyper4mance2k]

Originally Posted by arghx7

Generally true, yes, but just an FYI: backpressure has been used as sort of free pumping action by manufacturers to drive auxiliary devices to improve performance in gasoline engines. Two examples are variable induction systems (Mazda, specifically older rotary engines) or low pressure EGR (new Nissan Juke engine).

I have been building and racing rotaries for almost 20 years; no such thing exists... Mazda used reflective intake pulse tuning to pressurize the intake manifold to increase power. I have personally tested this on my old 90 S5 and saw up to .8psi of poisitive manifold pressure on a NA S5 13B.

The only time Mazda used exhaust back pressure was on the acutators that opened the 5th & 6th ports on NA engines.
The whole point of the 5th & 6th ports was to reduce exhaust timing and overlap on the intake stroke at low RPM to increase part throttle drivability, not to make more power. FYI, the better and more free flowing the exhaust the more power a rotary will make, and NA cars make more power when the acutators are pump driven, and they make even more power when the actuators, sleves, and the entire assembly are thrown in the trash.

My Hybrid S3/S4 13B Weber IDA carbureted monster that got over 25 mpg.

[ame]http://youtu.be/U0vbPTuvCzs[/ame]
[ame]http://youtu.be/MdmIgmxvjuc[/ame]

[continuecrushing]

in for video of tractor pull, and a partial throttle dyno chart

[KoolBRZ]

Originally Posted by Smoke Destructer

Wait, are you running an UEL tune with EL headers?

My A/R header is slightly unequal in length, (see pic), so I can run either tune. I will be on the VIP Performance dyno on Dec. 5th, so I will have some results to post then. I will also be on their dyno the following Friday 12/12, and will have results to compare between the modified A/R header, and the same header unmodified. Everything else will be the same including freshly loaded, unadapted tunes from Stock, and OFT versions 2.0 EL, 91 Oct EL, 91 Oct UEL, versions 2.062 91 Oct EL, and 91 Oct UEL. I feel 6 tunes, including the stock tune, is enough data to draw conclusions about whether or not the modifications make any difference, not how much difference there is.

[arghx7]

Originally Posted by Hyper4mance2k

I have been building and racing rotaries for almost 20 years; no such thing exists... Mazda used reflective intake pulse tuning to pressurize the intake manifold to increase power. I have personally tested this on my old 90 S5 and saw up to .8psi of poisitive manifold pressure on a NA S5 13B.

The only time Mazda used exhaust back pressure was on the acutators that opened the 5th & 6th ports on NA engines.
The whole point of the 5th & 6th ports was to reduce exhaust timing and overlap on the intake stroke at low RPM to increase part throttle drivability, not to make more power. FYI, the better and more free flowing the exhaust the more power a rotary will make, and NA cars make more power when the acutators are pump driven, and they make even more power when the actuators, sleves, and the entire assembly are thrown in the trash.

My Hybrid S3/S4 13B Weber IDA carbureted monster that got over 25 mpg.

We're getting off topic here but yes you are right, it was only used on the early 6 port induction systems before they were operated by smog pump (1989-1991 non turbo) or electric motor (Rx-8 Renesis engines). It's sort of like early VTEC in the sense that, clearly you would be giving up a light to have a single fixed high lift profile, so you needed to have the non-VTEC profile and an oil pressure switching mechanism.

With the n/a rotaries, it's best to have the shorter duration port timing for low load driving and a staging system. The secondary ports were staged with a mechanical linkage in the throttlebody and the aux ports were staged pneumatically with backpressure. That evolved to a vacuum solenoid for the secondary ports on the Rx-8 and electric motor for the auxiliary ports.

We're talking about the same thing.