1 2
Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
1/13/24 11:16 p.m.

I wish this had been built. Plans dated 1985 for a Group B rally CRX using twin 1100 VF bike engines. That would be 242 hp (total) at 9500 rpm. It would have sounded nuts. 




 

With today's 1000cc bike engines in race trim an easy 400+ hp.     

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
1/13/24 11:55 p.m.

Holy cow, I misread. The proposal was for FOUR bike engines. This would have been competing at roughly the same time as the 4WD RX-7 of Rod Millen. 

Tom1200
Tom1200 PowerDork
1/14/24 12:19 a.m.
Purple Frog (Forum Supporter) said:

With today's 1000cc bike engines in race trim an easy 400+ hp.     

Current 1000cc stock sport bikes are now 200hp.......you'd be looking at 450-500hp in race trim.

Piguin
Piguin Reader
1/14/24 1:03 a.m.

So, who is going to build it and bring it to the challenge?

4 engines, no need to crazy with tune, I think 800 hp would be enough. 

Keith could do the engine management and sync since he brought it up :D

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
1/14/24 1:15 a.m.

In reply to Piguin :

Each engine gets its own engine management. They'd basically be separate. Just feed them all the same throttle signal (a good use for DBW!) and come up with some sort of Rube Goldberg shifter. 

etifosi
etifosi SuperDork
1/14/24 3:25 a.m.

 

Wrong thread?

kevlarcorolla
kevlarcorolla Dork
1/14/24 7:13 a.m.

I allready built it,with just one bike engine in the middle where it should be :)

 Too much weight at the corners doing it as proposed.

 I've driven a few quite good race cars,the best I've ever driven handling wise was the true mid engined geo.

 Telepathic steering and you felt like it pivoted from the middle not steered with the front

kevlarcorolla
kevlarcorolla Dork
1/14/24 7:16 a.m.
chandler
chandler MegaDork
1/14/24 8:50 a.m.
kevlarcorolla said:

https://youtu.be/_AbPkpyLRW8?si=n0RIBOpq7jsNMm54

Glorious sounds

kevlarcorolla
kevlarcorolla Dork
1/14/24 9:19 a.m.

In reply to chandler :

Thanks :)

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
1/14/24 11:25 a.m.

So the documentation says electrically actuated clutches. I'm wondering what the power transfer looks like. With four bike engines, you've got four transmissions. An intermediate shaft joining the two paired trans? From left to right, you've got a wheel, a half shaft, a transmission, an intermediate shaft, a transmission, a half shaft and a wheel?

kevlarcorolla
kevlarcorolla Dork
1/14/24 11:43 a.m.

In reply to Keith Tanner :

That right there is while cool to dream about makes no sense to try and make a reality.

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
1/14/24 11:46 a.m.

In reply to kevlarcorolla :

I wasn't planning on building it, so dreaming about solving the technical problems is all I've got!

In 1985, this may have seemed the most logical way to get 484 hp using Honda power. There's some redundancy, too, if you lose an engine you just stick it in neutral and you've still got 75% power. Rallies were longer and tougher then. 

kevlarcorolla
kevlarcorolla Dork
1/14/24 12:01 p.m.

Roger that! :)

Forgetting about costs it didn't get built because the chances of it being reliable were slim to none.

Having stuffed a VTR1000 twin into a Justy and owned a 1st gen crx with similiar sized engine bay I'd say getting 2 in AND whatever method used to transfer power to the wheels would be crazy tough to pull off.

 They had turbos in '85,make more sense to "simply" add another crx engine and transaxle to the rear and boost both...in the end the weight would be similiar if not lighter actually.

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
1/14/24 12:41 p.m.

The engine is a v twin, so two of them side by side is plausible. The side view shows them fairly far forward and low (which doesn't seem ideal, but hey the Quattro had five cylinders way out there). I'm sure whoever drew up these plans had at least some rough measurements. 

There were turbos on 85, of course. But I don't think Honda used them anywhere. This is roughly the same time as the 323 GTX which only saw what, 250 in race trim? The quad CRX would have started off a lot higher. There was a lot of crazy "how do we take this to the next level?" thinking at the time. 

It was a Canadian team that was proposing this. Maybe they felt that using mostly-stock engines was easier than developing a turbocharged option from scratch. 

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
1/14/24 12:43 p.m.

The twin engine CRX was built just before this - it was an '84, I think. I remember that it ended up being heavier than Racing Beat had hoped it would be, and slower. They ended up dropping in Accord engines for the second round. 

Jim Pettengill
Jim Pettengill HalfDork
1/14/24 12:59 p.m.

Back in the '60s I seem to remember that someone had plans to build a CanAm car with four bike engines, don't think it ever happened, though.  Some truly wild ideas back then - witness the original plans for the Shadow with the air brakes and tiny wheels before the FIA banned movable aero.  Group B ws so cool, I understand about the dangers, but I would love to have seen this CRX and also the planned factory Mk1 MR2 actually run.

kevlarcorolla
kevlarcorolla Dork
1/14/24 1:18 p.m.

The V-twins aren't much narrower at the cases then an inline 4 suprisingly.

There was a guy before my time ice racing here that did an 80's accord with 2 engines both with stock auto trans.

 Got tired of old timers saying how they'd like to see my geo run agains't it.

 I woulda lapped it in a 12 lap race just like everything else,the geo was in the mid 1600lb range and 150hp with perfect gearing for the job.

 Adding 350'ish lbs at the back of the car helps nothing when braking/turning with limited grip.

 I'm all for whacky powertrain ideas(the Justy options were sled engines with cvt,rotary with adapter to use stock trans,inline 4 chain driving the stock trans or Vtwin chain driving the stock trans)they just need to make sense and be feasible for the performance targets.

Loweguy5
Loweguy5 GRM+ Memberand Dork
1/14/24 3:39 p.m.

In reply to kevlarcorolla :

Please tell us more about the car in your video.   That.  Is.  Awesome.

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
1/14/24 3:42 p.m.

In reply to kevlarcorolla :

What sort of speeds did you see? After a certain point, power/drag becomes more important than power/weight. Also, you had extreme traction conditions - I wonder what a difference that makes. I've never done any real ice racing, just a snow autox. 

Obviously, the car didn't get built. I don't know why. It may not have been logical, it may have been too expensive. But I'd love to see it run.

Appleseed
Appleseed MegaDork
1/14/24 3:42 p.m.

What if each engine was connected to a separate CV joint? You could tune a sensor in the steering column to throttle steer on demand.

kevlarcorolla
kevlarcorolla Dork
1/14/24 3:55 p.m.

In reply to Keith Tanner :

I'd only see about 75mph on the straight,the 1st yr the car was wingless,2nd yr a pair of BIG wings and it was slower on the straight but faster overall.

 We used small street legal studs in poduction tires at 19 per foot,grip is better then non studded but way way less then say gravel.

 

 Based on 20+ yrs of playing on the ice total car weight and more importantly weight location is key,every single car I've run got better the more stuff you thru in the dump.

 About the same as most forms of motorsport I'd say :)

hybridmomentspass
hybridmomentspass Dork
1/14/24 4:08 p.m.

Any more info on this 4WD RX7 mentioned earlier??

kevlarcorolla
kevlarcorolla Dork
1/14/24 4:16 p.m.

In reply to Loweguy5 :

R1 engine,chain driven,4 wheel steering.

1 2

You'll need to log in to post.

Our Preferred Partners
5OZsSD1dUDDUAcbboEzlj1eCSgtoEtIsdkZvIZm3uj8PYnTDSkUuuz2NPMrGmjKs