I made the trek up from Naples to the dyno day last Saturday at Pettit Racing. I had a chance to oogle three different 3-rotor cars currently at the shop including the blue/silver striped car featured in SCC.

What amazed me the most about the installation (and this may seem to be a paradox) was the apparent simplicity of the installation and the complexity of the supporting hardware. The entire engine can be, essentially, disconnected electrically with only three plugs. It's very apparent that much thought/engineering has gone into the making of the Banzai three rotor.

Additionally, and I should have taken a picture or two, the engine could have been moved back 5 inches minimum, even more if you were to use a custom intake manifold. Pettit has done just such a manifold for the two-rotor drag car. Cam also commented that if one were to mount it further back that a new subframe would not be needed. What would be needed is a new driveshaft naturally, and a shortened PPF, although for Cam, elimination seemed to be the better option. They run their race car without a PPF which completely shocked me. Apparently, additional bracing is used elsewhere. If anyone has more insight into this method, I'd love to hear about it.

Why PFS had to cut into the firewall I will never know. Perhaps a bit of tranny tunnel massaging for the starter would be necessary at most.

All this got me to thinking that perhaps I should not re-invent the wheel. All his setups use the stock turbo system yet produce wickedly "usable" hp which I would imagine is thoroughly entertaining than any 2-rotor setup. Frankly I'm still under the impression that going to a single will yield not only more hp, but more reliability. Creating a shorter motor, my original intention, seems to be overkill and unecessary. Regardless, it would be a relatively unproven design and who knows how sturdy it is compared to the 20b. I'm sure there are numerous improvements an engine builder could make to the 20B to increase reliability.

The obvious knacker in all of this is the location of the stock shifter. In my dreams the solution would be to simply (ha!) swap in a Hewland 6-speed sequential, as used by RE Amemiya's 2&3 rotor creations. http://www.hewland.com/svga/gearbox_range_current.htm
Specifically the IGT-C or maybe even the SGT. There's already a bell housing available.

Still, the appeal to a custom 3-rotor made out of more readily available parts is still there. In the end, I want a car I can enjoy NOW as opposed to 5 years down the road, LOL.

 

Do you know if Cam still has that Hewland gearbox for sale?

 

Hrm...didn't ask him actually...I noticed that there is a 5-speed dog/H-pattern box being manufactured here in the states which handles up to 600ft/lbs. of torque as well. There's info on the Hewland page. It's a tunnel tranny, just like the SGT.
Michel

 

The reason peter does this is so that the engine is pushed backwards so it will disrupt the weight ratio as little as possible. If you can find pictures of both conversions, peter's motor is back near the firewall, while pettit's is still up front.

 

Right I understand this. I've been to Pettit and I've seen their cars in person. What I'm saying is that where the 20B is installed by Pettit, there's still at a minimum 5-6 inches to slide the engine back WITHOUT cutting the firewall. By using a custom intake manifold, I believe you could ELIMINATE the need to cut the firewall like PFS did.
Michel

 

I talked w/ the PFS mechanic who did most of the fabricating, and he told me part of the problem was not disturbing the steering arm geometry and such, because in the firt 3-rotor conversion they did, the handling was all screwed up because of this (among other things).

They ended up moving it back AND down significantly, necessitating a custom oil pan etc.

I don't know how Pettit engineered it so that his conversion doesn't suffer the same shortcoming

 

pettit moves the steering rack, and spindle arms down so they are out of the way

mike

 

Again, if you did a custom intake, you wouldn't need the custom pan either. If you think about it, but the REW and 20B have the plethora of vacuum hoses and wires underneath the manifold. Go with a single or a non-sequential, and all of that junk is gone. There's just a BIG empty space and there's really no reason for the height of the stock manifold. The 20B isn't any taller than the 13B although the oil pan may have some additional height added.

People also say the Pettit car suffers from bump steer. Most of those who comment have never driven the car however, and neither can I so I cannot comment. People "theorize" that moving the steering rack creates bump steer. Cam, who obviously would downplay any negatives, says all cars have some bump steer but no one who has driven the car on the track has ever complained.
Michel

 

the way i understood it was that pettit moved both the rack and the spindle, or both ends of the tie rod, an equal amout thereby keeping the stock bumpsteer.
and yes there is tons of room under the plenum, on my car even with the 2 coils, and stock fuel/water part of the vacuum rail there is still enough room for me to get both hands in there and remove the wiring harness without pulling the intake off

mike

 

However, the tie rod length would be incorrect. Moving the rack and knuckle lower means the rack would have to be wider and the knuckle hole further out. Just taking the current assembly and moving it lower as-is would still result in bumpsteer, because the ideal tie rod length and pivot points change with rack height.

 

i looked at my car the other day and measured it up.i looked and pondered why myself they had to cut it back.there is alot room back there.as far as a custom manifold to fit it i thought of that too.i was going to do an inline motor type of manifold for the rew.as u see crispeed got there b4 i did.u could also do this with a 3 rotor.i am going to look into ,when my motor blows,doing a 3 rotor conversion.i believe if u rewelded the mounts forward,if possible,u could use the stock subframe.i like to experiment.

 

Isn't it possible to slide the stock box back and create a rod linkage so the shifter is in the right place?

 

Actually Cam commented that if the engine were slid back one could probably use the stock subframe.

CC, not sure about a linkage, might make it pretty awkward feeling. I have thought about that as well however. Some sort of a dog leg may work, but then again there's really no room to do something like that. You'd also be moving the shifter off axis and off the pivot point so there would almost have to be two "shift" rods with a connecting linkage. ****, I think I just found the solution! :-)
Michel

 

yes this is possible.shifter feel i dont know.but i have seen guys do it with 13b's in rx-3's and r100's.and they said it felt great.i looked at the subframe.if push it back all the way to the firewallthe u would hafta make engine mount supports further back and a longer oil pan hole.but that is just gonna take some welding

 

The non economic solution: install a corvette transaxle. Designed to handle the torque, lots of clutch/flywheel combos available and would give you all the room you need to slide the motor back. Though I imagine it would be difficult to fab mounting points for the transaxle.

 

And it would require a complete re-engineer of the rear end and associated suspension...a bit more work than I was looking for :-) One of the Hewland gearboxes would be much easier and you could go full sequential.
Michel

 

why just use the 5 five speed.that turbo tranny is made to handle alot more than u think.so is the rear end.if u wanna get that tech,then get a cusco or kaaz lsd and chromoly rear ends

 

The FD tranny is not going to hold450+ft./lbs. of torque for very long. If I do this I'm going to do it right and in the most trouble-free (car maintenance/rebuild) manner possible.

I've also considered the www.gurumotorsports.com transmission upgrade which converts it to a dog box, no synchros, straight cut gears. It keeps the 5-speed but the three rotor is more than flexible enough to handle "just" five gears. I don't know how well it would hold up to drag strip launches.

As for the rear end, a Kaaz or Cusco would be a necessity. Ari's car, however is now breaking OTHER things in the rear end besides the differential and axles. They're converting the car to three rotor as we speak and he expects to encounter further drivetrain problems as the power goes up considerably. They're already breaking stuff with the two rotor! This probably means they'll find a solution for the problems which is good for you and I.
Michel

 

lets put it this way.japanese are doing it without steering problems and cutting the firewall.we just believe in slappin **** in without research.but what do ut think about my idea of throwing it in there?also they encounter alot problems cuz they are complete drag car.not a street strip car.i would get a better tranny though.i would like to be able to attach a t56 tranny.with the 3 rotor shoved as far as it can go , the shifter would be in the stock location, just like a v8 transplant.

 

Using a T56 and the engine shoved back 6-8", the shifter will be in the stock location? Just wondering if I read this correctly. :-)

Do a search for "interesting 3-rotor pics" or something along those lines. I believe I posted it last month. It shows the RE Amemiya 3 rotor engine in and out of the car. It uses a custom intake which allows it to be positioned back further. They're using Hewland transmissions however.

Outside of RE, the only other shops using three rotors are Axis (the three rotor three turbo setup) and Stillway. Both are drag cars. I don't have any images of the Stillway engine bay off hand, but I do have Axis pics. It uses the stock intake and is shoved back as far as it'll go without hitting the firewall. The alternator is just a bit ahead of where it would be on a 13B setup.

The only other problems I see in moving the engine back would be starter clearance and clearance for a turbo manifold between the engine and the strut tower assembly. One would have to almost have a semi long tube design manifold (tuned) or position the turbo behind the strut tower and thus run into ABS interference. That would be relevant for a very large turbo, say a T51 or something of that nature.
Michel

 

cool thanks about the pics.but no,u can place a turbo further back.matter of fact look at a t51 it is under the strut tower,the compressor side and no messing with the abs.
correct on the t56.look at jimlabs v8 transplant.the v8 is right on the firewall.the t56 is shorter than the stock 5 speed.making it directly located in stock position.

 

Got any good pics of the Axis? Other then those on the Thai site? please post them

 

the re amemyia car is thier jgtc race car.
1) its peripheral port
2) you cant assume that the firewall is stock either

mike

 

I have some pretty detailed pics of the engine installed (but nothing else) and it gives a clear shot of the firewall area. It doesn't appear to be modified at all. I'm aware it's their JGTC 300 car btw :-) I was referring to the turbocharged three rotors of Axis and Stillway. I do have addional pics of the Axis car out of RX7 Magazine. As soon as it's returned to me, I'll scan them in and post them.
Michel

 

Hmmmm, I dunno what the big deal is on this one...
I can slap in some plastic mil-spec connector copies that just adds $200 to the total cost of the installation.


-Ted