what bike engine is preferred?

[Bill Smith]

starting a locost - need some advice on what to use

 

things I think I know but not sure if they are correct

1. want low weight with as high hp as possible mainly for autocross

2. chain on bike needs to be on the left in order to get correct rotation for rear diff

3. some bike engines require a dry sump oil system if put in a car and used in high g turns

4. If a bike egine is used the front of the seven can be shortened

5. If a R-1 engine is used - there are several 7's that have nice web sites

6. It is desirable to balance the car side to side by shifting weight to the rider side to offset the driver

 

what advice is out there?

[slngsht]

do you have a $ figure in mind? that might play a role in it. dry sumps aren't cheap

[andrew7]

Hi Bill,

I was looking at your previous post questions. Here is where I found my cad plans, mine is a +4".

http://www.mcsorley.net/locost/drawings.htm

 

You said, "mainly for autocross". Do you want a car like Jeff U. , not street legal. The reason I ask is with a bike engine and the autocross rules you would be competing with purpose built race cars. That said, in question 4, yes you could make the car about 1' shorter but the look of the car will be changed. Regarding question 6, the engine could be place in the passenger compartment for the best balance.

 

Does your state require "powered reverse"? Mine does but some states don't. If its an autocross only car no need to think about it.

A home engineered solution is about $100 to get past the letter of the law verses a Quaife reverse box at $1500.

 

I know the Hayabusa needs dry sumped or a swivel pickup tube with a modified pan. Figure an extra $1000 on top of the engine price. The Suzuki and Yamaha engines don't need it from my research. A flat six Goldwing motor with shaft drive might be usable, low center of gravity and has reverse built in but the rear end might need flipped to get the rotation correct.

 

First gear on the superbikes is long, I heard on an RC51 first was good to 80. A short autocross course could be run in first. I think I'm 65mph at redline.

 

Used engines are hi tech and cheap, 150hp at 150# about $1500.

 

The downsides:

 

The flywheels are too light for traffic and hills, after 3 summers I still stall it once or twice every time I'm out. The engine will die if you rev to 5000rpm and drop the clutch, not enough flywheel mass.

 

I still screw up my shifts and the sound is terrible. One reason I don't let others drive my car because I don't want them learning on my engine. Blow a clutch and pieces and parts are circulated through the engine oil, blow a tranny gear and remove the engine. Everything is related. The parts are no longer trying to move a 400# bike but a 1000# car and this means more stress.

 

There is a fair amount of vibration, read thin shoes on the pedals after 1.5 hours = numb feet.

 

I envy other seven owners that are able to tour with their cars. I've never done an Interstate. Take your car to a 4 lane freeway drop it in second then drive at the speed limit for 5 minutes. This is the BEC highway experience.

 

My dad has a V6 in his seven and it is quick and comfortable. It is a completely different feel than mine, his feels like a car where mine feels like a go-cart. My opinion is the closer to a track weapon you make, the less fun you will have on the street. I still wonder if a Westfield Miata on the street would be more fun to drive than my car. The paddles and Formula soundtrack are addicting on back country roads. Hope this helps.

[S1Steve]

Andrew7,

You give some great insight on the pros and cons of a BEC.

I never thought about a engine made to push a #400 bike, installed in a #1000 car. I went the other route and installed a car engine in a 7( Zetec in a S1)

Well just want to say Thanks for a well written post.

 

:cheers: Steve

[Bill Smith]

thanks,

use will be mainly autocross weapon - will not attempt to make street legal

 

what engine do you use and also what rear diff - I have a couple rx-7 2nd gen - really like Ron's design but could use measurements to start from.

 

Bill

[andrew7]

Bill,

I have a 2005 Yamaha R1 fuel injected, I know Jeff Underwoods R1 engine is a few years older and carbed.

 

I used a Ford 7.5" rear end with an open differential. I started with a 3.08 ratio and found it difficult to pull out, went to 4.11s and were great but 55mph was 7000 rpm. I think this lower gear would put you in the proper rpm range for autocross. I went back to 3.08s with lightweight 13" wheels. The Ford and Mazda rear end pinions are offset to the passenger side about an 1". I think Jeff started out with an RX7 rear but change to a Toyota unit for higher gears and more top speed. I believe he's running his car mostly at VIR. I built my basic frame from McSorley's plans and altered them as to the changes I wanted, you didn't specify what you needed. There are a lot more builders over at LocostUSA, someone has already solved the problems you will face.

 

I uploaded some 8mm video of the car here. It should give you some ideas. The second half shows the engine at idle.

 

http://www.veoh.com/videos/v16367710fWHQZyK4

[Bill Smith]

that is cool

[R1 Seven]

Bill,

I have a 2005 Yamaha R1 fuel injected, I know Jeff Underwoods R1 engine is a few years older and carbed.

 

I used a Ford 7.5" rear end with an open differential. I started with a 3.08 ratio and found it difficult to pull out, went to 4.11s and were great but 55mph was 7000 rpm. I think this lower gear would put you in the proper rpm range for autocross. I went back to 3.08s with lightweight 13" wheels. The Ford and Mazda rear end pinions are offset to the passenger side about an 1". I think Jeff started out with an RX7 rear but change to a Toyota unit for higher gears and more top speed. I believe he's running his car mostly at VIR. I built my basic frame from McSorley's plans and altered them as to the changes I wanted, you didn't specify what you needed. There are a lot more builders over at LocostUSA, someone has already solved the problems you will face.

 

I uploaded some 8mm video of the car here. It should give you some ideas. The second half shows the engine at idle.

 

http://www.veoh.com/videos/v16367710fWHQZyK4

 

Hey Andrew! Hope things are going well with you.

 

One correction to your post above. My engine is a 2003 and is fuel injected...I don't want anything to do with carbs.

 

Yes, the RX-7 rear just did not have a low enough ratio avail. 3.90 was the best I could do. The Toyota has a 3.42 and is much better suited to the tracks that I run at. (VIR, Summit, CMP, Rockingham) The car tops out at about 135mph which is just about right.

 

Bill, I got your email the other day...I do not have Ron's email address. Sorry about that.

 

[andrew7]

Hi Jeff,

 

Sorry about that, I knew you started your build earlier ('01) and your pictures looked like it was carbed. Mine is 2 years newer but the FI system has a completely different look, a pair of tubes with 8 butterflies and 4 injecters hanging out. I heard Yamaha makes big changes every 2 years.

 

O.T. Is your normal speed range and average in the 70 to 130mph range? I haven't been above 85, I need to increase caster it feels twitchy at that speed. I enjoy watching your videos, currently trying to transfer older 8mm of the Dragon to mpeg files.

 

Dad is still working on his 7 Rodster, http://www.veoh.com/videos/v1494005328ms9mBa

[tnttim]

thanks,

use will be mainly autocross weapon - will not attempt to make street legal

 

what engine do you use and also what rear diff - I have a couple rx-7 2nd gen - really like Ron's design but could use measurements to start from.

 

Bill

 

 

If you are really into the Autocross idea I would first get a copy of the rules for which ever club you plan on running with.

 

As mentioned before SCCA there is no Seven'ish bike engine class. They will lump you in with purpose built, very much smaller, road rockets that scream.

 

As for NASA autocrossing, I could not tell you. They dont exist (or dont seem to), here in Michiagn. Track stuff yes.

 

 

Build your car to the rules and as fast as you can, or think you can. But you will find out real quick that if you are lumped in with a lot of cars that are by nature faster than you, you may not enjoy racing for very long.

 

 

SCCA also has ruling about where the enigne may lie in the car. If you plan on sticking with a Bike engine I dont think that matters much. But as for an auto engine there is a limit to where you can move it to and stay 'legal' according to the rules.

 

If you can give us some more details about how and where you plan on racing this, there are lots of people here who have most likely been down that road.

 

We surely like to help.

 

tim

 

 

 

 

 

 

 

[R1 Seven]

Hi Jeff,

 

 

O.T. Is your normal speed range and average in the 70 to 130mph range? I haven't been above 85, I need to increase caster it feels twitchy at that speed. I enjoy watching your videos, currently trying to transfer older 8mm of the Dragon to mpeg files.

 

Dad is still working on his 7 Rodster, http://www.veoh.com/videos/v1494005328ms9mBa

 

Yeah...thereabouts. It could be a couple of other things. Check your toe. I run mine at zero for a reference. Also it could be buffeting at that speed. These cars are so dirty in the air. That took some getting used to at speed. I just hold the wheel straight and things work out.