118 replies to this topic

[Sean12]

sukidawg, thanks for your input, and i assure you i will not just dive in an slap any old brakes onto the car, as you can imagine i have my safety in mind at all times as i think anyone would. my initial statement about going inboard using bike brakes was just an idea, an idea i was discussing with a mate working on my diff, he has many years experience racing and buidling bike engined cars and owns his own race engineering company, so kinda has an idea about what he is talkin about, an i have complete trust in him, he has far far more powerful machines than i could ever imagine building and is still living and doing very well racing. all ideas i talk about in this forum are indeed IDEAS, and will be followed up with much research and advice from those with vast amounts of experience. I really appreciate your input sukidawg and you clearly know what your on about, however im only just starting on the project an have not thought about things as in much detail as you obvisouly know about just yet, but appreciate your input.

and yes mike i completely agree, i feel the brakes will more than likely cope, but i will be doing checks, and i totally agree about cooling, this was one of my main thoughts after deciding to hopefully go down this root and will have to think about creating a way to draw air up and over them from under the car or somethin.

oh an yes my lectures are only lecturers but know more than enough on the theory side of things, and know far more than i do, but like i say im mainly taking the advice from my mate with the experience and am in safe hands, everythin i make and do i will be gettin checked over with him anyway, and then obviously like i have said before tested in uni on the test rigs etc....

plus yes grasstracking isnt your sunday tv racing but is prob more suited to the type of build were doing, its a very similar i guess in many ways, afterall chris from zcars hasnt done too badly.....

oh an will deffo have a read of this carrol smith book sounds like a good read nice one, i love how you even knew the ISBN number to lol, your like a fountain of knowledge lol

[SukiDawg]

Lol.. to be honest I read it off the cover - its on my bookshelf...

Yeh sorry - I was a bit ratty after the work day when I wrote that "big I am" story earlier. Everything in engineering is about learning constantly, and although I am probably able to claim engine knowledge - a lot of the suspension stuff I'm re-learning or seeing for the first time at the moment.


What kind of rear suspension layout do you have in mind? Are you going to use trailing arm as per the Z car or something else? Inboard brakes are great for unsprung mass - but one disadvantage is that they reduce the anti-dive capability of the rear suspension. The brake torque is reacted through the frame rather than through the wishbones.. with a short wheelbase as on a mini that might not be ideal.. Just what I read and think about anyways... No direct experience to draw on.

On my car - with it being freelander rear diff, its not an option. The inner CV's plug straight into the diff, there is no ring of bolts to mount a brake bell.

[Sean12]

sukidawg, oh right i see lol thought it was quite a random bit of information to know of top of head lol

and no dont worry, we all have those days. Just early doors on this project and as you know im only a 3rd year, on not even a automotive degree lol but i will always do my best to research somethin as best i can and design an produce somethin that will hopefully work ok, using literature and peoples knowledge and experience as guidance. i do appreciate all your input and help though, you clearly know what you are talking about.

as far as suspension, i was initially thinkin about just following like a sheep and going for trailing arms, but after speaking to my lecturer, thought it could be nice to try an come up with some sort of wishbone set up. but again i will have to look into this deeper and see whats what an what option would be best suited in the time/money/difficulty sittuations. i will deffinately have to read into in more detail about the inboard brakes, but you do make very good points, obv having a lower unsprung mass is always a bonus but like you say there are always drawbacks.....watch this space lol

cheers again suki

[Sean12]

hey guys,

thought i would do a little update, popped round to mates house to check on diff, was looking very good.

diff opening has been sealed and welded, with a bolt hole left (inch an a quarter if i remember rightly) for changing oil etc.

ends of the diff shaft openings have been lathed into to allow the oil seals to be put in.

bearings have been delivered and are ready to be put on, there are 4 bearings for extra strength and support. the bearings are a sealed type to prevent any damage or debri getting into them.

the race spec aluminum is going to be collected soon to make the billets.

all the welding is going to be ground back and smoothed and all cleaned up nice, these are just progress pics.

The output shafts are also being lathed to allow another bearing to fit, and the casing and output shafts are going to be lathed and machined to enable the circlips to be placed outside the casing instead of on the awkward place that was right in the middle of the gears that is now unaccessable

this guy does some properly top work, and seriously knows his stuff and many thanks go out to him. This is one part i didnt want to get wrong but deffinately in safe hands.

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[Sean12]

just out of interest is anyone a wizz at working out sproket sizes ?

i need to figure out a sproket size for the fireblade engine, if i post up some info on the engine gearing ratios, wheel diameter etc would anyone be able to help ? or anyone that has a blade engine in there mini what ratios there runnning.


cheers guys

[bikem1ke]

Give me the data sean i'll sort you out with gearing stuff. what revs do you want to be doing at 60mph in 6th? How fast do you want to go?

[SukiDawg]

Just out of interest, do you know what grade your aluminium actually is?

"race spec" could mean anything


All the better grades of ally originate from the aircraft industry - they have the resources to develop their own alloys, or at least back in the fifties when most modern alloys were developed they did.

Most likely you want a bit of 2014A - non weldable but contains a bit of copper to give machinability etc. T6 temper is the most commonly available in the UK. Roughly twice the tensile strength of standard commercially available alloys such as 6063.

Its dear though!

[Sean12]

Cheers mike ill send you the data

[Sean12]

i have had a play with the spreadsheet and come up with this, if you could have a look and tell me your opinions that would be great,

this is based on 13" superlites with standard road tyres.

also this spreadsheet seems ok but doesnt seem to take into account weight ?!?! wouldnt this be a factor that was needed to be taken into account ?

cheers guys

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Edited by Sean12, 19 November 2009 - 08:17 PM.

[R1mini]

Using another spreadsheet I get 118mph at 12000 close enough, thats using 175/50/13 tyres. The weight is accounted for by the reduced gearing the original bike is probably geared for something like 180mph

Cheers
David

[bikem1ke]

Weight doesn't affect speed because of gears Sean. Ive made a spreadsheet with what i think are the gear ratios, wasn't the fireblade a cbr900rr not a 1000rr?

[Sean12]

yea it is a 900RR, its 919cc. Just noticed on the pic is says 1000RR it looks like a typo on the spreadsheet i downloaded as the date says (98-99) and they obviously didnt do the 1000 then. they did make the 1000rr tho, but not till a much late date than this engine (2007 if i remember rightly).

so were you guys getting similar sprocket sizes then ??

[bikem1ke]

Yeah getting exactly the same speeds for those sprockets sean. You need to look at the torque profile of the engine and how you want to use the car, if your cruising at 70 do you want your engine doing 7000rpm?

[Sean12]

yeah have thought about that, will speak to ABperformance tomoro an have a chat with them again! Sprocket sizes dont seem to bad, yea 70mph at 7k rpm is fairly high but cant see me doing much cruising at 70 to be honest, but will be getting a second sprocket made up for cruising speeds, afterall being slip sprockets wont be the end of the world to change. Also have a warehouse lined up for the mini now next door to my mate doing the diff cant wait !!!!

cheers for the info guys !

[Sean12]

Just a quick update,

been doing some calcs with my mate and just put in the order for my split sprockets, 16 - 54 this should be ideal for the road and not tooo viscious. but should still have enough get up an go. here are the speeds in each gear at 2 rev ranges. another split sprocket will be brought in the future when the car is up an running for track day use.

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a 520 chain is going to be ordered to. which will more than cope with the extra stresses from the added traction.

also got the reverse system sorted now, got an automatic chevrolet geared starter motor and ring gear so should be very light and effective, and hopefully abit smoother lol

aluminium is still being sorted and machined to take the four bearings.


sean

Edited by Sean12, 27 November 2009 - 10:57 PM.