Formula GRM: My New Challenge Project

wearymicrobe wrote: First I love the idea of this. But could you do a ford motor with the same dimensions as the formula motors. They run 1600 pintos right.

A Ford engine would be cheap and easy, but getting a Hewland gearbox in under the Challenge cap would be tricky.

I did 4 years of FSAE in college, plus a few extra years of tinkering. I have defeated many variety of stock bike wiring harnesses, without releasing any appreciable smoke. So if you want some advice or any bike engine car related input, I'm down.

I have a bunch of 600cc Honda CBR spares, but I'm assuming you are going liter-bike or bigger. But if there is anything specific you need, ask. Beer as payment.

Tell me more about these CBR 600 parts that are in Connecticut! I'm also looking for a 914 steering rack....

Bike engined car experience is good, too.

In reply to Woody:

80% of the stuff is at my parents house in West Haven, the other 20% spread around friends garages.

Off the top of my head I have: 2 CBR 600's, one F3 one F2. The F3 was a supposed runner I bought from a roundy-round guy in upstate NY. I'm half expecting the bearings to be toast from oil starvation. The F2 I also bought from him, but he was unsure of the condition.

Wanna see a Honda Fit with an extra 200HP in the trunk?

1 CB1-400cc. Followed me home from college. Has a supposedly thicker head gasket, since it was destined for an ill-fated turbo project.

1 GSXR 600, 2001 I think. A chucklehead I went to school with cracked some parts in the head rebuilding it. I am in the process of putting the thing back together with an eBay head.

So, to quote a friend, "It's not very good, but there is a lot of it".

The part that might be interesting to you is I got about 8 sets of carbs for various 600cc bikes and 2 sets of GSXr carbs. Tons of extra wiring parts including CDI boxes and regulators. And just crap in general. So when you get going just give a (internet) yell.

I'd be very interested in a running CBR 600, and I'm not far from West Haven.

I sent you a PM. Readers Digest version: let me dig some crap out of my parents shed.

You can get into an AWD WRX trans for reasonable money by buying it in parts. They either kill the center diff or the syncros. You can buy one with a broken front half and one with a broken back half for a few hundred bucks total. Weld the center diff, remove and plug rear driveshaft, fab shifter linkage and you are set. Of course getting a WRX motor in that chassis would be tough. Adapter?

I'd have to back-half the chassis to fit Subaru stuff back there.

I'm still waiting to roll the WRX parked next to it. That will open up a lot of options for me.

Doh! Knew you had the Porsche and the Miata, didn't pay close enough attention to see the WRX. Rallycross maybe?

I miiiight know where a Garrett GT12 with F4i manifold and a custom F4i thick copper head gasket reside :D Just gotta be careful, I hear the gearbox will grenade with too much boost :o

Woody wrote:

wearymicrobe wrote: First I love the idea of this. But could you do a ford motor with the same dimensions as the formula motors. They run 1600 pintos right.

A Ford engine would be cheap and easy, but getting a Hewland gearbox in under the Challenge cap would be tricky.

Maybe make your own "Hewland" with VW bug box with a flipped ring gear? Weren't some of the first Hewlands VW boxes turned upside down with beefed internals? Kennedy makes adapters but they are $$$. If you have access to a CNC you could make your own adapter. Check out Hewland MK1

Per asked me to post this info I sent him here. I have pictures of a North South 1000cc set up with a drive shaft adapter if you want to see them. In response to Per's question on shaft drive bikes:

Choices are slim as far as performance bikes. Chain is preferred on true sportbikes due to weight, power loss, and handling issues with the shaft. If you truly want DSR legal under 1000 cc displacement your only real choice is an older BMW K bike donor. It's a lay down inline 4 so it also has some interesting packaging issues with the exhaust ports facing down.

If displacement is free, there are some interesting choices, several V-4's up to 1400 cc, some big twins, but the best of in my opinion is a Goldwing/Valkyrie flat six. I would bet a wrecked Valkyrie drivetrain can be found cheap and 1500 cc of flat six pulling through six carbs must sound pretty cool. Plenty of hop up parts including superchargers.

Check on something before you jump in: I kind of remember reading somewhere that bike driveshafts spun opposite of car ones, so unless you invert the diff, it will spin backwards.

Another option if you want/need shaft drive is to run a bike engine in a North/South arrangement and use an adapter to convert the countershaft sprocket to a U joint holder. If you look at the DSR network (not the forum but the site with the pics) for Ed Dickinson's JED, you will see that arrangement. I think it's similar to the MayKar that was at Nationals and used an RX7 or Miata diff. This will allow you to use just about any chain drive engine/trans.

For your steering rack take a look at the lightweight rack and pinions used in dune buggies. I think Forumla First is using them now too.

http://www.dansperformanceparts.com/buggy/susp/buggysusp%20rack&pinion.htm

Link is just an example of what's out there, you can hunt around on ebay and probably find them at a good price.

Here's the North/South driveshaft layout example. Works right off the bike engines countershaft sprocket:

That's brilliant. I never would have thought of using the countershaft sprocket. That opens up a lot more engine options.

Do you have any idea what he used for a rear differential? It looks like the answer may be Miata.

In reply to Woody:

If you don't need reverse, use a bike engine like the dwarf cars. Here's a link to the adapter you need to convert the sprocket to a driveshaft they are cheap at only 75 bucks

http://www.speedpartz.com/dwarf_driveshaftadapter.htm

http://www.speedpartz.com/hawk_driveshaft_adapter.gif

You can also divorce the differential from a VW style transmission and utilize 930 CVs to power your drive wheels

Yes, that's a Miata pumpkin. I think that's the car that also uses Miata uprights (I could be mistaken, there's another that's similar)

Per

Per Schroeder wrote: Yes, that's a Miata pumpkin. I think that's the car that also uses Miata uprights (I could be mistaken, there's another that's similar) Per

I'll have to find some more info on that car. I planned on using Miata uprights and will most likely use the rear as well. It might look a little clumsy, but I don't want to use a solid axle and I don't think that I can do a chain drive limited slip (and case) and keep the project under budget.

What is the "countershaft sprocket"? Is it the output shaft of the transmission with the sprocket to drive the rear wheel? (I'm not a bike guy)

You want to talk to Mark Yakich (maycar on dsr forum). He's the guy I know that made DSR/BMod car in this fashion. It's heavy compared to purposebuilt stuff, but it works and would be cheap. I pm'd him on dsr.forum about posting his experiences here.

Yes, the countershaft sprocket is the front sprocket on a bike.

Here is another picture I have of the rear of that car:

You can use the countershaft trick on front-engined cars as well. One thing to watch is that Miata rear end ratios tend to be on the short side for bike engines. If you have the diff from a 1.8 Miata, easily available ratios are 4.1 and 4.3 followed by 3.9. There are some 3.636 unit out there but you'll have to buy it new because they were never used in the US. And that's it - there's nothing taller.

Consider a Cadillac CTS rear. They're a bit smaller and come with ratios like 3.23, 3.42 and 3.73. You can buy a new one with a posi for the price of a junkyard Miata Torsen.

I want to see many, many pictures of that car above. Lots of interesting stuff. These are D Mod cars?

Keith, if you are looking for numerically higher, the t-bird had the 8.8 and can get a 5.13:1 or down to a 3.08:1. All sorts of locker/lsd available too. Ring and Pinion

Yeah the 8.8 is huge and overkill for a BEC.

In reply to Woody:

If you have access to a Bridgeport and a lathe, you can make a chain drive setup. I can't guarantee it will be cheap, but it can be done.

I lucked out and scored a stock LSD from an S2000 for $6 on ebay a few months ago. It's a way beefier than needed, but it was the right price.

As lore dictates, the FSAE torsen special was a center diff in some Audi transmission that nobody cares about. I cant confirm this application, but I will say that the "university special" was a good piece of kit. Heavy, but good.

Oddly enough, I have access to a Bridgeport and a lathe...

And I am starting to investigate the Audi transaxles, though that would take the car down a different path entirely.