holyyyy....amazing build! the quality of fabrication and work is top notch!! Well done sir!!

 

Really liking the slides throttles Logan. I am however really surprised you dropped that much mid range and top end HP with changing the rear exhaust section. Are the losses attributed to the extra bends near the mufflers?



Edit: I just remembered you did the last dyno plots in cold weather. What where the ambient temp differences between those runs?

 

Trots has this one covered

Yep everything you said is correct. The slide throttle seals with the engine vacuum, which has telfon surfaces.


Thanks t-von! The old exhaust had more bends actually, but was longer. The new shorter system has changed the effective tuned header length, so needs some adjustment. The weather was warmer this time, but the dyno runs are SAE corrected so the horsepower will not change with outside temps.

 

Yea, I may have dreamt up this kind of thing once or twice. Unfortunately I'm gonna have to stick with living vicariously through you...

I'll just go back to the corner and cry myself to sleep.

Looks stellar!

 

Does reducing the Inlet runner length effect the torque curve across the whole rpm range? And move the HP higher up in the rev range?

I have seen an rx8 with a 13b pp in the bay used for hill climbs and the inlet runner length was exceptionally long and I was told this was to help increase the mid range torque/hp?

 

Longer runners move the torque peak lower in the rpm range which will also move the hp peak lower in the rpm range. Since rotary's have such a long rev range, Mazda engineered it's intakes with different length runners to keep the torque curve moving higher as the engine revs. On the stock Rx8, the primary runner is the longest followed by the shorter secondary and aux runners. Opening the secondary and aux runners later in the power band will move the torque band higher. This is the same thing that happening with Logan's set-up. As soon as the PP's open, the torque peak moves higher in the power band allowing him to keep making power way up top.

 

What arethe advantages to a slide tb? Increased flow due to the restrictor (only word I can think to describe it) being moved out of the airflows path versus a butterfly which still is in the way?

Definitely increased flow as you point out, but also we cannot discount the advantage removing the butterflies and shaft has on dynamic pressure wave tuning.

Whether straight Helmholtz tuning (as in this case) with the reflection of the opposite wave form or dynamic effect tuning with the full reflected wave or even the wave from opposite rotor- the wave has to pass that butterfly twice.

Imagine the intake manifold as a musical instrument when thinking of pressure waves.

I think you could hear the difference if you stuck an open butterfly in a brass instrument, now imagine the effect with much greater force than vibrating lips creating the pressure waves and the fact that we are actually harnessing the forces that have reflected back to the lips as it were.

 

I fully understand the reflective way tuning due to living with my dad, who is a 2stroke genius. Lol.

He has explained the reflective wave tuning to me hundreds of times.

It's amazing how a rotary has similar tuning aspects to a single cylinder 2 stroke engine.

 

Hey Logan... I notice that you have license plates on yours. I assume it's street legal. Not sure if you have vehicle emissions where you live, but any idea what kind of carbon this baby is producing and whether it could pass emissions with a high flow cat and the semi p-ports disengaged??

 

its a rotary, TONS.

 

Your not gonna pass any emission test with PP's small or large that doesn't have a port that completely closes off the runner. You need a surface that allows the apex seal to actually skim across the surface when the port is shut. Even if you have a slide plate 1" upstream, you will still have the overlap as the apex seal crosses over the port. Air will leak from one side of the seal to the other and out the exhaust. For a Rotary to have great emissions, you need zero overlap. Rotarygod explained about this a couple years ago.

 

Got it, so would a large street port NA possibly pass? Just curious.

 

^ That all depends on the closing timing of the exhaust and opening timing of the primary and secondary runners. The less over lap you have the better your chances. There are ways to port without affecting either timing. Do they test over their is AZ?

 

Are you kidding? Tailpipe standard is the same as Cali. Cars are tested on dynos at real-world operating conditions. The only relief AZ owners get is a little more lenient on visual inspection criteria and no CARB standards. Basically, if it passes tailpipe emissions on the dyno you get your golden ticket.

So, I'm guessing if you had a 3 rotor NA in your 93, the emissions station testers would punch in the year and VIN which would bring up the stock twin turbo 13BREW criteria which is what you'd have to pass, correct?

 

Wow didn't know that about AZ. I thought is was all about the heavily populated areas. The only testing in west Texas is visual and safety. Dallas they test emissions I believe. Now as far as the engine matching the vin?? I have no idea!

 

Logan, really enjoyed reading through your build thread(I was away from the computer from Jan-April and completely missed it). I stumbled upon it earlier when your wheel/tire thread popped up in the race tech forum. You've done alot of really cool stuff. Any idea when you are going to be able to get it out on track? I'm sure you are staying extremely busy with work, but just curious... that thing is chomping at the bits to see the race track.

 

I actually have taken it to mid-ohio about 4 times now. Just finished getting my competition license, and scheduled to compete in a race during october Even with basically no setup adjustments the car is feeling great. Going to de-tune the engine to fit in ST2, and later next year gear it back up and try ST1. Obviously my driving skills are much below the potential of the machine however. Practice makes perfect right?

 

HELL YEAH! Congrats on 4 weekends and getting the comp license! Having MO in close by is awesome as well since Nationals will be there at least this year and next.

Like Pete said, I'll be interested to see if you can keep the torque when you choke it down to what I guess is 300rwhp... what are you thinking the torque will look like when you do that? Is the 3 rotor capable of having close to the same torque as hp at that level? You should just stay in ST2, we have way more cars than ST1

That is actually the reason I ended up going with the LS engine.... no one measures torque, only hp and weight. I got tired of being faster than the Corvette's in the turns, and them pulling me hard in a straight line. Now I have better suspension and braking and the same engine... I'm running out of excuses... well, the car is... not the driver I'm giving some serious thought into a 400ish stroker and choking it down to my 335hp and having a retarded amount of torque for TTS/ST2 next year.

Any video's of the car?

 

Thanks Brent Currently it is at 250rwtq, and even de-tuned can run it right there. Many intake and exhaust revisions have been going on, and maybe 260-270rwtq is possible. But not much more. Basically the ST2 setup will have tapering torque after 7k, yeilding 300rwhp from 6500-10k. I will most likely stay in ST2 all the time. I like the idea of entering ST1 periodically to give me a reason for high horsepower development however. Danny Popp is a machine, wont be seeing the rear end of his car any time soon!

I do have some videos but not worth posting yet. I want to take good vids of the next time out though!

 

If you post again without pictures and/or video, I'm going to drive to Ohio, steal your car, take some pictures and videos of the joyride, put your car back, and post them here for you.

You've been warned.

 

Barban, i couldnt have said it any better. i came into this thread in hopes new pictures would be up, if not, i was going to make a threat a long those lines.

picS!!!!

 

Haha okay okay, I will post something once I download it from the camera. Promise!

 

Logan, where are you gonna get this thing up to 500RWHP

 

As soon as he dynos it at 4500 Feet below sea level! Or gets off his *** to test out some more custom parts...

Update! Update! Update!

 

When he adds another rotor