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Robbie UltimaDork
3/7/19 11:25 a.m.
Stampie said:

In reply to Robbie :

Smart people designed the Titanic also.

fair enough - but would the titanic have even floated or run without those smart people? My concern is that I've watched the only other bike engined challenge build team mess around trying to get their car to run right for 3 solid challenges in a row. They're running a modified bike engine (exhaust, cooling system, clutch, intake, fuel, etc) I don't want to be in that boat. I want this to run exactly like the stock bike, so I'm putting priority on using stock parts in their stock config. 

¯\_(ツ)_/¯ UberDork
3/7/19 11:38 a.m.

Yeah, I'm all for messing with stuff- but I'm on team "keep stock airbox, cut the car."  You can reinforce that area after cutting if you need to, and sportbike engines are pretty finely tuned so I wouldn't want to mess with the airbox either.

AWSX1686 SuperDork
3/7/19 12:37 p.m.

I would agree with Chris and say to keep the stock airbox in the stock orientation. The less variables the better. 

MulletTruck HalfDork
3/7/19 12:49 p.m.

I know a guy that has put Hayabusa engines in Kawasaki frames and he runs open carbs on one and the one he sold Jesse James has pod filters on it if I remember correctly.

His name is Norm Wilding and lives in Missouri. You might be able to remove the airbox all together. Search Kawabusa and Kawabusa2.

TurnerX19 Reader
3/7/19 1:00 p.m.

I would willingly abandon the airbox, but would not invert the injectors.

captainawesome Reader
3/7/19 1:19 p.m.

The air box is actually a super engineered part of the system. Keep it if at all possible. Individual filters would be a huge step back in performance from my experience.

wheelsmithy SuperDork
3/7/19 6:02 p.m.

I agree on stock airbox, as much as is possible, for What It's Worth.


Robbie UltimaDork
3/10/19 11:03 a.m.

Robbie learned how to bend titanium devil

Dusterbd13-michael MegaDork
3/10/19 11:05 a.m.

Did it involve a backhoe and giant torch? Thats how we bent the amc headers.....

Robbie UltimaDork
3/10/19 2:28 p.m.
Dusterbd13-michael said:

Did it involve a backhoe and giant torch? Thats how we bent the amc headers.....

Not anywhere as cool as that, unfortunately!

I was trying to bend all 4 pipes together. And failing. Then somehow mr genius here decided to try to bend one pipe at a time. Guess what, heat it red hot, stand on one end with boot, bend. It wasn't even hard to bend them all the right amount to keep them in a line. Dunno how I never thought of this before.

Robbie UltimaDork
3/10/19 3:50 p.m.

Got some help making a template to cut the parcel shelf.

It was a great template, but I promptly threw away all our hard work when I started cutting. Oh well.

I'm pretty pleased so far. Next I'll think about how to fab up something to get fresh air to the intakes.


Note to self: soapy water is basically the only possible way to install the throttle bodies into their rubber isolators on the head. 


Stampie PowerDork
3/10/19 5:10 p.m.

In reply to Robbie :

captainawesome Reader
3/10/19 8:27 p.m.

I like windex for lubricant, goes on soapy and slick but disappears easily. Learned that mounting motorcycle tires.

Apexcarver UltimaDork
3/11/19 12:19 a.m.
captainawesome said:

I like windex for lubricant, goes on soapy and slick but disappears easily. Learned that mounting motorcycle tires.

This needs to make the "say what" section in the magazine...devil

barefootskater Dork
3/11/19 9:59 a.m.

I'm a little late, but my experience modifying motorcycle intake systems is don't. Every single time it has only made things worse. Glad you are keeping it stock, it should run just fine that way.

Robbie UltimaDork
3/12/19 11:49 a.m.

worked a little more on just getting the intake to fit perfectly last night. Still not 100% right but getting closer. 

MarkyMark77 New Reader
4/16/19 5:25 p.m.

Hello again Robbie and good to see you're making progress !

The amount of  work when you break it down... to finish a car, is considerable at this level.

I read your post originally at a time when I was 100% convinced I was going to go down the bike-engine route.

I was building a broad picture of the possibilities, generally, with this car, using the power to weight ratio from the Group 5 Dallara Sil as the yardstick.

Assuming you can get up to 225 bhp and 750kgs on your car, you will be on a par with the Dallara.

But there is a knock-on effect on the way the car handles, of course.

The fundamental changes to the rear of the Dallara are the relocation of the rear top mounts 1" back and 1" out on each side.

This means fabricating new rear lower wishbones which use the original front and rear chassis mounts, the arms are just longer and angled accordingly, likewise you need to lenghten the driveshafts.

Then you can use the adjustable coilovers from VickAuto, along with their big-brake kit, which are fine for 13" or 15" rims.

You can then lower the car by nearly 3"on the struts, just like the Dallara.

Then you can measure the exact offset between the hub face and the strut tube, and specify a custom offset 7J rim and run a 225 section rear tire.

When you come to putting on the wheels, they won't fit because they foul the arches.

Chop off anyyhing that's in the way and weld in a gusset, job done.

You can then add some plastic fender flare to tidy it up cheaply.

You will also need to - lighten the bonnet by cutting out cooling vents and opening up the to of the rad-bay to flow the hot air over the bonnet - relocate the fuel tank to the front luggage compartment, fit a front ARB, and a quicker steering rack, all basic stuff.

What you have with the bike engine is a lower c-of-g than the Dallara, which of couse means that your AutoX car is already very close to being able to be configured for sprints, hillclimbs, track work, or fast road, or simply a road legal track-day car.

If you can emulate or improve the fundamental dynamics along these lines you will end up with a very special car, make no mistake and regardless of whether the driving seat is in the middle or to the left or right.

Build it right, set it up right, drive it right and on the right roads for your ratios, and as a driver assume to look for torturous twisties where the maximum speed between the corners is 125 mph/ 200 kph.

Now imagine some twisty canyon roads (or is that too cliched) and your car which looks a bit better than the Dallara on paper, and a stock F40 Ferrari.

Put a very good driver with good knowledge of the road, in the F40, and put a very, VERY good driver with EXCEPTIONAL knowledge of the road and set them off in front , and behind the Ferrari on two separate tests, to see what happens.....

I imagine the F40 would not be able to pass the X.

I imagine the X would be able to pass  the F40 on the inside and get clear long enough to prevent the F40 from passing.

This is because the X is really narrow, is lighter, jinks faster, and is stupendously quick exiting corners.

Let me say that I think we share the "bangs for bucks" approach but that we are building very different hybrids, and in relative terms I suppose I am one notch down in terms of performance and one notch up in terms of cost.

The fastest X would use a supercharged K20 (400bhp) and be lowered, long wheelbase, and wide-track, with composite bodywork - not necessarily Dallara style, just whatever works - eg these cars :




I eventually decided to stick with the original sohc and original transmission, on the basis that 100 bhp/litre was achievable and that the original gearbox would be ok - I decided to stick with an open diff but to fit close ratios from the Punto GT.

The engineers are well on the way with the build, pics to follow if anyone's interested - using Omex ITB's like this -


The specs for the engine are -

Strip and assess donor engine, clean all parts. Turns out this is from a Lancia Prisma.
Lighten flywheel and reface surface, machine front crank pulley to suit new crank sensor trigger wheel, micro polish crankshaft and deburr casting. Balance crank assembly.
Polish connecting rod flanks to remove possible fracture points, have rods shot peened. Balance connecting rods.
Balance all pistons.
Deburr cylinder block casting and remove casting flashings, reface block surface to bring pistons to correct squish height. 
Flow test cylinder head before doing any port work to assess its potential gains, modify ports to increase air flow, machine valve seats to fit oversize inlet valve and add a 3 angle seat cut to all seats. Reface valves and add a 3 angle cut. Modify combustion chamber to suit compression ratio and increase fuel burn efficiency, port match inlet manifold to cylinder head. Reface head surface to give desired compression ratio. Flow test cylinder again to get finished results and flow gains. 
Dry build engine to take measurements of bearing clearances, squish heights, piston to head clearance, valve to piston clearance, camshaft timing etc. disassemble and final machine any parts if needed. Thoroughly clean all parts prior to final build.
Final assembly of engine. 
Set engine up on test rig. Check all electronic sensors and wiring. map basic ecu settings for engine to start and run. Run engine to check for any leaks etc, balance throttle bodies and set idle. 

Parts -

Inlet valves  39.5mm x4
Performance camshaft
Vernier camshaft pulley
Various gaskets, seals etc
Race quality big end bearing shells
40mm dcoe type throttle bodies
Stand alone ecu
Wiring loom
Injectors x4
Fuel pressure regulator
Throttle position sensor
Throttle linkage
Air filter
Inlet manifold
Crank position sensor
Trigger wheel
Ignition coil pack
Ignition leads
Water temperature and air temperature sensors
Miscellaneous items, bolts, nuts, electronic  connectors etc.

Good Luck !!

MarkyMark77 New Reader
4/16/19 5:31 p.m.

In reply to MarkyMark77 :

the exceptional driver is driving the Fiat, I forgot that bit lol

Robbie UltimaDork
4/17/19 5:52 p.m.

In reply to MarkyMark77 :

That sounds like a hell of a build!

davbro New Reader
11/15/19 9:04 p.m.

Great build thread!  i was just thinking about doing a central seating position on a project (no specific reason other than i thought it would be cool)...curious to see how yours wil be done.

Any updates?

enginehelp New Reader
6/23/20 4:21 p.m.

Any updates? I was really excited for this project and it fell off a cliff haha

Robbie (Forum Supporter)
Robbie (Forum Supporter) MegaDork
6/23/20 6:16 p.m.

Hey all! Sorry for the lack of updates. Other builds have jumped in line, but my plan is to be back at this for GRM challenge 2021.

Probably have changes in plan in store too.

Indy "Nub" Guy
Indy "Nub" Guy PowerDork
6/23/20 6:54 p.m.

In reply to Robbie (Forum Supporter) :

Supercharged 3.8 ?

Dusterbd13-michael (Forum Supporter)
Dusterbd13-michael (Forum Supporter) MegaDork
6/23/20 7:08 p.m.

3400 v6 with itb and a five speed midmounted and running on megasquirt. 

enginehelp New Reader
6/24/20 12:33 a.m.

In reply to Robbie (Forum Supporter) :

Hohoh now that's exciting, can't wait

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