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DaveEstey PowerDork
3/31/20 10:07 p.m.

After 8 years I've parted out my hillclimb RX7 and purchased its replacement. Enter - Busa Grande!

It's a Baby Grand converted to road race form and powered by a Gen I Hayabusa drivetrain.  Trophys on the seller's wall from this car included SPU wins at Daytona, Sebring and Homestead.  Sadly, health issues that will never change meant he couldn't race anymore and it has sat since 2016. Enter Dave with a wallet and here we go!

Yes, Baby Grands usually have a roof. This one has been speedsterized. 

Under the body lies the truth of the beast. 




Plans are to clean things up and prep it for hillclimb and a little road race action around New England. In the future - even more road racing and travel. 

DaveEstey PowerDork
3/31/20 10:11 p.m.

Step one - remove the fuel system that my hillclimb tech guy has already reached out to me about. Also rework some electrics and the exhaust while I'm at it. 

I'm a stickler for good wiring, so this will take some doing. I'm going to make a body harness since the engine already has its own harness from the motorcycle. The fuel starvation tank has been removed and I'll be simplifying the system and adding in a more robust filter unit that I used on the RX7. 

Still weighing muffler options. This one chokes down right before it turns down the body, which I want to alleviate. 

RossD MegaDork
4/1/20 6:34 a.m.

Thats awesome! The flex hose for the air inlet gives me pause. Any chance you will swap it out for hard pipe?

DaveEstey PowerDork
4/1/20 8:10 a.m.

In reply to RossD :

It's getting an OEM airbox. The sheet metal manifold wasn't sealed right and never would. 

Ian F
Ian F MegaDork
4/1/20 8:11 a.m.

That's really cool.  After some Googling, it looks like the Baby Grand series is/was around for quite awhile?  I'd never heard of it.

Patrick GRM+ Memberand MegaDork
4/1/20 9:35 a.m.

Disappointed in the lack of piano content

gumby GRM+ Memberand HalfDork
4/1/20 10:21 a.m.

Just one sanctioning body set of rules I googled up; 1500lbs, 76" wheelbase, 56" trackwidth.

Sounds like a riot with 'busa power!

Robbie GRM+ Memberand MegaDork
4/1/20 11:07 a.m.

Yeah I'll be taking notes ...

TGMF HalfDork
4/1/20 3:09 p.m.

curious to see the drivetrain configuration. I see the offset driveshaft in the last photo.  I assume the integrated trans is still used....how is the output attached to the driveshaft? 

java230 UberDork
4/1/20 3:19 p.m.

Ohhhh Fun! I see the ledgends cars for sale often.... That always looks like a riot.

Robbie GRM+ Memberand MegaDork
4/1/20 3:28 p.m.
TGMF said:

curious to see the drivetrain configuration. I see the offset driveshaft in the last photo.  I assume the integrated trans is still used....how is the output attached to the driveshaft? 

I think the common way is with a part that is essentially a really short yoke that has the bike output shaft spline.

Bolt it on the output shaft and attach ujoint.

camaroz1985 HalfDork
4/2/20 8:54 a.m.

Looks like a suitable replacement (upgrade) for the RX-7.  Will be watching this for sure!

¯\_(ツ)_/¯ PowerDork
4/2/20 9:04 a.m.

Well, this ought to be exciting.

What happened to the caged FC shell?  Did it have a title?

DaveEstey PowerDork
4/2/20 9:14 a.m.

In reply to ¯\_(ツ)_/¯ :

Sold it to a drifter. No title. I was tired of dealing with flakey people after the part-out portion. 


In reply to TGMF :



DaveEstey PowerDork
4/2/20 9:17 a.m.

While I was bebopping around the shop and cleaning things I decided to paint my other valve cover. The RX7 had gold engine bits, so this is a quiet homage. 



golfduke HalfDork
4/2/20 12:11 p.m.

As you already know, I strongly approve of this and am following along voraciously. 


DaveEstey PowerDork
4/2/20 9:41 p.m.

As I've been eyeballing and cleaning things up I decided to stop screwing around just pull the engine. Glad I did. Some things need addressing.



Yeah that's a drill bit being used as a push rod for the clutch slave. Also yeah - that driveshaft adapter is roached. Also also yeah - somebody welded that shifter with their feet.

I can pick up the front of the car now. I can also pick up the back of the car. Time for a degrease and powerwash and then redoing some tinwork and heat protection. 


DaveEstey PowerDork
4/4/20 9:46 a.m.

The car came with two sets of injectors. Both sets have some faults. Luckily Suzuki used the same injectors on basically everything, so I was able to score some cleaned, flow rated and matched injectors for $40 shipped. 

They smell like solvents, which is good. They also have fresh o-rings. Score!

DaveEstey PowerDork
4/9/20 10:07 a.m.

pulled the oil pan to make sure the swinging pickup was working and found some treasures. 

Prevailing theory is that someone over tightened a bolt that was too long and punched the node out the backside, which caught in a tooth and snapped it. I'll know more soon. Initial inspection didn't reveal anything.

I had already budgeted for a new engine, but I'm not sure I'll need to pull that trigger just yet. Could be a replacement gear and fix the hole that got punched in (if I can find it). 

dculberson (Forum Supporter)
dculberson (Forum Supporter) MegaDork
4/9/20 12:38 p.m.

In reply to DaveEstey :

Man, that driveshaft adapter area looks like someone lost the driveshaft bolts while racing and the loose driveshaft just beat the snot out of everything around it.

Robbie (Forum Supporter)
Robbie (Forum Supporter) GRM+ Memberand MegaDork
4/9/20 1:02 p.m.

IF you need to get a new engine, and are selling the existing one, I may be interested.

DaveEstey PowerDork
4/9/20 2:20 p.m.

In reply to dculberson (Forum Supporter) :

yeah looks like it ate E36 M3 at 8k rpm


DaveEstey PowerDork
4/11/20 8:56 a.m.

Dear journal,

Some days are kinda weird. Take today for instance. I split the case on my Busa engine in search of a chipped gear tooth, but after inspecting every single gear - none of them are missing teeth. Kinda makes a guy wonder.

All the best,



DaveEstey PowerDork
4/11/20 9:00 a.m.

In other news, the exhaust cam gear adjuster has definitely slipped, which would be one reason why she didn't run so good. Beyond the injector that was basically stuck open.

Nice and clean inside though. This engine has been opened before. The balancer has been removed and replaced with a straight rod, consistent with racing activities. 

Note the cracked boss for the valve cover bolt in the upper stiffening frame. I have a replacement head I can pull parts from, but this is general indication of the previous owners torqueing methods. 


DaveEstey PowerDork
4/11/20 9:02 a.m.

I also got my supplies to redesign the electrical system of the car, which is a bit of a rats nest on the chassis side. The motorcycle side of things retains the bike's harness, minus a few items.

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