Regulation changes for 2019

Everything related to the administration of the season

Re: Regulation changes for 2019

Postby Martin Kemp » Mon Dec 17, 2018 1:45 pm

Has there been a Brexit decision - I must have missed that,

Martin
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Re: Regulation changes for 2019

Postby EmlynC » Wed Jan 02, 2019 7:22 pm

Given proposed transverse gearbox regulation:

Gearboxes in the transverse engined cars are now free, subject to being synchromesh and from a transverse engined car

I started to consider options. As a lot of work has been done with fitting the existing gearbox into the design for the ESC, and I have no knowledge of potential alternative gearboxes, I looked at the Bacci Romano website to find that they have an off the shelf synchromesh gearset (11/35 – 14/33 – 18/33 – 21/31 – 23/28) available for 2,272 Euro. I asked Matt to convert these numbers into something I could fully understand, and he can back with an interactive spreadsheet (copies available if anyone would like me to email it).

None of the standard Fiat diff rations worked with these ratios, and equally none of the alternative crown wheel and pinions that they already offer worked. I played with different ratios and a 3.6 diff at 8,000 rpm gives the following speeds in each gear:

41.06 mph
55.40 mph
71.27 mph
88.51 mph
107.35 mph

I therefore sent the following email to them on December 18th:

Dear Sir,

I doubt that in Italy you have ever heard of the 750 Formula, but it is the longest running club formula in the UK having started in 1950 (Colin Chapman's first racing car was a 750).

For a number of years we have used the 1108cc version of the Fiat FIRE engine, and up until now cars with a traverse engine had to use the standard Fiat gearbox, but from the beginning of next season the regulations have changed to:

Gearboxes in the transverse engined cars are now free, subject to being synchromesh and from a transverse engined car.


I have been looking at your close ratio kit (RC070) which looks interesting, but with the final drive ratios available the top end speed would be too low. Please see attached a spreadsheet that has been put together by a student at Brunel University.

Looking at the numbers a final drive of about 3.6 would appear to be ideal, but is that going to be possible?

I have attached some images of my project to give you a feel.

Best regards,

Emlyn Coldicott


Today I got a reply:

Hello,

good morning and a happy new year!

Thanks a lot for your kind request had before the Christmas holidays. My compliments for the project, it seems really well made and very good looking as well.

About your kind request, there isn’t any problem for us to realize a special final drive ratio 3,60 (…..for example a 15x54). The RC070 is always in our products range.

In order to realize to you a quotation, have you a quantity request for the RC070 and the special final drive?...so that I can make to you the best possible quotation.

Thanks and regards,

Giulio Dialti


Before going back in detail, I would like to ask:

1) Do other people think that the 3.6 ratio looks about right?

2) Would anyone else be interested in being part of getting the quote? (I'm sure that there would some savings over an individual order. The price for one of their existing crown wheel and pinion is 772 Euro.)

3) Does anyone have any thoughts on other "standard" gearboxes they would like to share on our site?

Emlyn
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Re: Regulation changes for 2019

Postby Martin Kemp » Wed Jan 02, 2019 11:47 pm

Those are very low ratios and their standard final drives are also very low, so i think it must be a rally gearbox.
The ratios are better spaced so you would get 5 usable gears rather than 4, however instead of just using 2nd at the start and sticking to 3rd,4th and 5th during the race I would use 1st and 2nd at the start and still just 3rd 4th and 5th during the race so the benefits would not be that great but it is possible that their higher 2nd gear might be useful for slow hairpins. I have the 1:1 5th gear and 4.07 final drive which gives 4,07 overall for 5th which is not too bad.

A 3.6:1 final drive with their ratios gives a 5th gear of 4.39. My engines would run out of revs with that gearing and I think that as rough guide a final drive of 3.33:1 would be nearer the mark for me. I have not had much trouble with the FIAT box myself, but I understand it is the synchro on 3rd that gives the most trouble so a special gearset would not help that unless there were modifications to the synchro as well. Modifications that improve the gearchange speed would also help. Of course their Dog Box would be interesting but is not allowed under the proposed rule change.
Anyway from my point of view the cost looks prohibitive compared to using reconditioned standard gearboxes at about £350 exchange and learning how to repair them. I have used up 1 so far but I do not yet know what went wrong with it.
Weight saving, weight distribution, engine tuning and downforce are my development priorities for this season
There are other people also looking at alternative gearboxes and it would interesting to know what hey have found

Martin
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Re: Regulation changes for 2019

Postby pbove » Thu Jan 03, 2019 9:21 am

I think a 4:2 top gear works for most circuits - Martin is right, the gearing you mentioned would be too low. You need to gear for a top speed of around 115 at the faster circuits and, with most engines, there isn't much useful power above 7,500 rpm.
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Re: Regulation changes for 2019

Postby F1300Tony » Thu Jan 03, 2019 5:40 pm

If the transverse gearbox is made 'free with syncro' , in my opinion the main benefit would be the freedom to change the box to one that is known to be strong and has an abundance of available ratios, either by buying a s.c. gearset or using a mix and match of standard gears and final drive. What I don't know yet is whether that that box will fit.
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Re: Regulation changes for 2019

Postby EmlynC » Thu Jan 10, 2019 6:59 pm

I'm really glad that I put up my post – I was thinking in the wrong way and potentially going the wrong route, so I'm really grateful for the comments.

I had an excellent email from Tony where he expanded what he has said here. I would like him to share his detailed thoughts with everyone, but it is up to him to decide what he wants to publish.

Peter's comments about 115 mph and 7,500 rpm are interesting – the students at Brunel had been watching in car videos on YouTube, but from that they came up with the assumption that the top speed was about 100 mph.

Emlyn
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Re: Regulation changes for 2019

Postby Martin Kemp » Thu Jan 10, 2019 10:55 pm

We only get up to maximum speed briefly but getting it optimised is very important because that is when the overtaking action usually starts.
Most cars have a limited range of intermediate and final ratios available so compromises are necessary.

Peter's figures look pretty realistic to me,

Martin
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Re: Regulation changes for 2019

Postby Dave Robson » Fri Jan 11, 2019 10:59 am

Emlyn,
If it helps, here are the speed & revs at Mallory Park. It's not the fastest circuit but you are over 100mph for a lot of the time! I would have said that 111mph would be a good estimate for the max speed but there again, I'm not as quick as Peter!!
Dave
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Speed & Revs at Mallory.JPG
Speed & Revs at Mallory.JPG (196.41 KiB) Viewed 840 times
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Re: Regulation changes for 2019

Postby pbove » Fri Jan 11, 2019 11:50 am

Interesting - in my experience, the highest speed I saw was on the Hanger Straight - with a tow, and a following wind!!
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Re: Regulation changes for 2019

Postby F1300Tony » Sat Jan 12, 2019 5:18 pm

There is always the possibility of a return to Thruxton one day!
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