4 Rotor 23A 3rd Gen.!!
 

Sorry I don't belong here yet but I thought I'd share. All I have to say is god daaaaaaamn

http://www.autotechmotorsports.com/projects-23afd.htm

damn thats so nice

I'm jealous

is that a first for the U.S. ??

sounds sooooooo nice

Old news. Jeff from Autotech here in San Diego is a great guy and has worked on my car. I've seen this car in person but never saw them start it up. It's a shop project car and those videos are pretty old (2003 I think), I have no idea what the current status of the car is now.

He does drive around an awesome 3 rotor that sounds absolutely mean.

I don't understand how they could lower the engine so far and not touch the steering and still have room for an oil pan....does the pan sit beneath the front subframe or something? :)

i would think that would be a heavy engine?

An easy 650 to the rear wheels would take care of that. ;)

maybe a drysump setup?

6-7" rearward, but the shifter stays in the stock location? if the motor got moved 7" back, wouldn't the shifter get moved 7" back too?

Rynberg, I think it's impossible to have an oilpan at that low a point. I'm sure they're using a dry sump pump (pics are too small to see the external reservoir/pump/front cover, but I'm sure it's there). Besides, you'd be crazy to not go for all the extra lubrication you can get!

I think what they're doing is lowering the motor SO low that it's actually backed into the tranny tunnel. And that's a pretty big area, which allows them to move the motor back pretty much as far as they'd like. I think at a certain point, you will have to cut away some of the sheet metal around the tranny tunnel, and maybe they're just not classifying that as "firewall."

GUITARJUNKIE28, there's actually an unused access plate just in front of where the stock shifter sits. So if you move the tranny back 6 inches or so, you can move the shifter 6 inches forward on the shift fork (inside the tranny), and have it come up out of the second (currently unused) access plate, leaving the shifter (in the cockpit) pretty much in the stock location.

The problem I'm having is, if you move the motor back 6 inches, and the tranny back 6 inches, you need to chop off 6 inches from the driveshaft AND PPF. That's easier said than done. Plus I'm sure physics-wise, the shorter driveshaft and PPF will leave the car extering considerably more force on them, making them prone to break, twist, or snap - all of which can be done on a high hp 2-rotor already. So doing it on a 4-rotor...uhh.... :eek:

Plus, having the engine sit so low...it looks like it's a lot lower than using the stock subframe. That's gotta be a custom subframe that's literally letting the motor hang close to the floor... while lower center of gravity is good for handling, I dunno how comfortable I am having my entire drive train lower to the ground than stock (from the outside...ie closer to the ground so it can hit and scrape on speedbumps and what not). If you look at how much space there is between the strut bar and the UIM, it's clear as day that the motor dropped a LOT more than just the depth of the oilpan. It DEFINITELY sitting lower than the stock subframe.

Lastly, HOLY SMOKES that 4-rotor must be heavy. The 20B is approximatly 120 lbs heavier than the 13B-REW. A 4-rotor is probably tipping the scale in adding another 250 lb easily. You could save that weight (some of it) by staying NA, but then again, if you're THAT crazy to do a 4-rotor and have THAT much room, you might as well twin turbo charge that BEAST!

~Ramy

Ok, I don't know about all that other stuff... But this is based on a 12A, so every plate/housing/rotor weighs less. Also almost everything about the motor (manifolds, exhaust, etc etc) would be custom, so it's going to be as light as they make it to be. Without all the PS/A-C etc I bet they can get the weight down quite a bit. Plus I suspect the weight distribution can be ok if they get it far enough back. If they want they might be able to go N/A and save all the weight of the turbo system.

All in all a very interesting motor.

Uhhh...I was thinkin more along the lines of 800 to the wheels.

word...also is that an ebay strut bar? how much does that motor cost and you buy a 12 dollar strut bar?. hey im not nocking it i have one too. im just confused?

I'd think that making the driveshaft and PPF assemblies shorter will allow them to be stronger, because less leverage can be put on them overall.

My biggest question with this engine is that the mainshaft is incredibly long, putting it under a considerable amount of stress loads farther away from the power transfer point (more leverage); I'm wondering how it will last with major HP loads put on it at high rpm.

I noticed that the FE stress analysis they conducted only used two lobes...

i'd be more worried about inertial load from the high rpm than the overall power.

True, but I could also easily see the mainshaft snapping from rapidly rising 600-800 HP torsional loads at even midrange rpm, which is what I meant; sorry, should've been more specific.

for sure theyll have some sort of tranny prob, I wonder how much torque its making.

I highly doubt it. A stock port 20B will only make 350 or so in NA form. I'm sure w/ a peripheral port you could see 500 or so...even though IIRC the RE Amemiya JGTC car is making about 330 (hence the GT 300 class it races in), and it's peripherally ported. I'd be surprised if a fully built NA 4-rotor made more than 700 hp...but I'd expect well into the low 600s torque.

That crossed my mind as well Kento, but not knowing any better, I was undecided which way it would turn out haha. Guess in simple (layman) physics (ie from my pencil fighting days :rofl: ), it's easier to break a (full) pencil than the shortest leftover segment of a broken (thus shortened) pencil. :D

Well, lemme put it like this. 20Bs have been known to experience bending and snapping of the e-shaft (w/ the stock twins; not w/ a large single) namely b/c of the higher "lateral" loading of the engine at low RPMs, which only occurs w/ the twin turbo setup. A large single makes power at higher RPMs, where rotating inertia will counter any lateral forces. This is also why early series 20Bs are undesirable, because the early e-shafts (which were improved in B and up series, btw) were deemed prone to flexing due to the "snap torque" of the twin turbos around 2000rpm when the engine was under high lateral load.

Having said that, even a single turbo 20B will have e-shaft flexing at high rpms (8K and up). B/c of that, there are a few guys (esp. the hardcore 20B guys in Australia & New Zealand) that are running multi-piece e-shafts (2 and 3 pieces). I'd think you'd most certainly need to have a multi-piece e-shaft on a 4-rotor, unless you're looking for a 6K or so redline :p:

Absolutely. Stock tranny is only good for about 550 ft lbs of torque, if that. There are a few guys in the 20B section who have totally destroyed the stock tranny at those power levels. But I'm sure if you can afford to piece together a 4-rotor and all the associated custom parts, you can afford a custom HKS or Guru dogmission w/ straight cut gears etc.

~Ramy

i get what you're saying. i just really think rpm's do more damage than boost.

The oil pan is probably the easy part. The oil pickup can be modified to pickup at the back of the engine with a large sump leaving the frontal area fairly flat. The engine could also be tilted slightly upward so the extra rearward length of the engine can fit underneath the stock transmission tunnel without modification.

The Fd's transmission has a access panel about 6" in front of the stock shifter. It can be moved forward to this location with some modification. The Fc turbo II tranny's can be done the same way.

There's a guy in Australia running an 1100 hp 4 rotor in a pink BMW, so I would expect that this engine can take at least that much.

That's what I was referring to.
Interesting. Didn't know about the multi-piece e-shafts, neat idea. Although I'd wager that their service life is somewhat short; any coupling between each piece surely endures some extreme structural stress in a very concentrated area.

The only time "rotating inertia will counter any lateral forces" is if there is sufficient counter-weighting in the opposite direction of those forces, and even then the mainshaft will still undergo major torsional loads. I doubt that rpm is the real reason behind the flexing mainshafts of the 20Bs you refer to.