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Naturally Aspirated Performance ForumDiscussion of naturally-aspirated rotary performance. No Power Adders, only pure rotary power!
From the "12A" to the "RENESIS" and beyond.
I haven't been on a Dyno with the megasquirt but seat of pants say i picked up some power and drivability is way better. I'm running sequential- only 2 injectors (id1000) this time and coil on plug instead if batch and 2nd gen ignition. I'd guess peak power is probably within 5 or 10 percent, of before but everywhere else pulls really good compared to before
Faster everywhere but it's less if an improvement on top compared to 3k-6k. Also a nifty thing is a Weber this big would stumble and big on quick throttle movement down low, my setup doesn't. It just pulls.
I'm really happy with the megasquirt and the ign-a1 coils in coil on plug configuration
That is encouraging. I can't wait to get mine running.
Originally Posted by mikey D
Also a nifty thing is a Weber this big would stumble and big on quick throttle movement down low, my setup doesn't. It just pulls.
Funny you mention this, because I remember seeing where someone had used one the 55 mm throttles on a non-race engine (I don't remember if it was ported at all), but they were saying the same thing about the throttle response and I thought it had to be the magic of having fuel injection and a good EMS. After seeing it, I remember thinking I sort have wished I had gone 55 since throttle response was one of the factors that made me choose the 50.
I hope Borla took the time to work out the TWM itb bugs.
I ran a pair of dcoe TWM itbs on a Ford Zetec motor 10 years ago. They look pretty, but were nothing but problems. The linkage between the 2 shafts was poorly designed and wouldn't hold a setting. The cable stay and connection to the shaft was a bad angle and didn't allow smooth throttle application. The plates would stick in the bores so when I tried to accelerate smoothly from a standstill they would pop open and jerk the car. Then one of the bushings came dislodged and walked out of the shaft bore.
I bought a pair of Jenveys from the UK and never looked back. Expensive, and worth every penny.
I bought mine directly from twm 10 ish years ago. I have none of the issues you mentioned. The throttle shaft is basically the same as the carb and goes though both barrels there is no linkage so to speak as we just have the 2 barrels. Same with the trottle pull. Its pretty much standard stuff.
i could upload a shakey cell phone video if it gives folks the warm and fuzzies.
I bought mine directly from twm 10 ish years ago. I have none of the issues you mentioned. The throttle shaft is basically the same as the carb and goes though both barrels there is no linkage so to speak as we just have the 2 barrels. Same with the trottle pull. Its pretty much standard stuff.
i could upload a shakey cell phone video if it gives folks the warm and fuzzies.
On a Zetec (or any 4 port 4cyl, really) you will be using two throttle bodies, and you have to synchronize the two for even flow. Us rotary guys have it really easy unless you have a rare dual DCOE manifold.
i've never had to sync a set, myself, but i kinda figured it was very complicated - both by what i've been told by people who have, and by virtue of the fact that i remember there was a special tool that Rotary Engineering had in their catalog just for that purpose.
Doing this lazymode... old Mazda paper has 18" from port surface to trumpet entrance (this is for peripheral port but should basically apply) providing resonance at 7k RPM, 16" at 8k RPM, 14" at 8.5k. Assuming the R26B was basically the same port configuration and matching the torque peaks to the other paper, its minimum runner length was 14" - if that's right, according to its paper, it was running 15" runner length at 8k rpm, 17" at 7.5k, 19" at 7k, and 21" at 6k RPM and below.
A whole lot of rules of thumb, assumptions and fudge factors in that list there, but it's a place to start.
Any chance you guys have a link to the old Mazda paper you could share? I'm very interested in the NA 6port bridgeport ITB race setup.
12-29-18, 09:55 AM
