RiF Posted January 20, 2003 Author Share Posted January 20, 2003 HELP HELP HELP *confused* Sorry chaps I am more confused than when I started looking at diff and gear ratios I have tried entering my own figures into the tables and it still confusses me further. ☹️ Anyone available for me to discuss the full ins and outs on the phone one evening. Just really want to have some better guide before going out into the market place. After just driving the tin top back 400 miles from Belgium trying to get some idea re rev drops, torque, gear ratios of the tin top to put some actual feel to what each of you has been explaining. Conclusion is I don't think that I would be able to judge what I want unless I drive a car for a few months in each spec ☹️ and that's impossible. So really need more advice, sorry. Richard in France six weeks to go before delivery of chassis to start building my Duratec 7 😬 Link to comment Share on other sites More sharing options...
Bilbo Posted January 20, 2003 Share Posted January 20, 2003 Hi Peter I must confess I was thinking of Curborough as one lap i.e. BMRMC (Marshall's club day) not the 2 laps. I am already hitting the change point into 4th on the straight in the final straight, admittedly only for a few seconds. That was on the BMRMC day 2 years ago. When the clutch was slipping last May I nearly DID use 5th . All my top speeds were MUCH lower that day. However, I would rather avoid doing that again with a slipping clutch. Quaife's gear calculator using 7750 rev (max power rev) give's a theoretical top speed of 107.03 mph in 3rd with current gearing, 94.4 mph with the 4.44. In fact half way between is more what I am getting now in third anywhere. In fact it makes me think I would be better checking what it really is in each gear before going any further. 8300 rev (change point) give's a theoretical top speed of 114.623 mph in 3rd with current gearing, 101.201 mph with the 4.44. Well I rather think I am not hitting over 100 mph in 3rd so the max power rev seems a more true figure. On BMRMC day on the 'first lap' its third full into Paddock change to 2nd after the bend into woodside, drop to 1st into the molehill, second into Fradley hairpin 3rd fairly soon after going onto the straight. Back 'nicely powered out' on the last half of Fradley, I was rather pleased with that at the time on the last 2 runs . However, I do not seem to reach these speeds anyway but I think thats may be braking too soon. . Well I know I was lots of BIG grins from Graham Ford, plus p*ss taking from Oily Rag . Still the car has a big weight in it err ME! Plus it does not like the braking going back into Paddock bends then adverse camber. Best read as I do not like....... bigger brakes would be a solution but the pockets not bottomless. I think it was more a case of I was confused where the timing lights were located. Well it was my first go... Is that the correct method 🤔 any pointers. Club day well all to pot with the clutch slipping at 6500 rpm then finally at 4500 rpm. Last event no race suit...... (mutter). I must say I was hoping to almost hit 100 mph on the run off time with the current set up if the clutch had been OK. Then again may be its just too little BHP/ton with me in the car. ☹️ Seems the program your using is different to Quaife. So I am a bit . Still they are only theoretical anyway no wind, road drag etc. As to the graph of my coast down power well if you remember my rev counter over read that day and the initial set up was wrong. The re-visit produced a different shaped graph. In theory it should be 7750 rpm but what's 150 rpm between friends. My biggest problem seems to be off the power 3rd to 4th at Cadwell. 'Can you hear me running' ......... OH YES and its music to my ears 😬 😬 😬 1988 200 bhp, 146 ft lbs, 1700cc Cosworth BD? on Weber's with Brooklands and Clamshell wings, Freestyle Motorsport suspension. Q 979 CGY Edited by - bilbo on 21 Jan 2003 19:10:33 Link to comment Share on other sites More sharing options...
Bilbo Posted January 20, 2003 Share Posted January 20, 2003 Hi Richard Well I feel just the same way I posted before.... all this leaves me rather brain dead. ☹️ At the end of the day 4.44 diff more acceleration 3.62 diff more theoretical top speed. However, its all only in theory as the slow down effects of wind and road drag come into play. If you know you can not in theory/practice get anywhere near the top speed in 4th then its over geared. In the last post I said think I check the actual against the theory seems a good start. Problem the conventional speedo will over read at speeds over 70 mph in virtually all cars. In a tin top that's easy to check find out what it is in a test report with 5th wheel, then see what you get difference = the error. 7ns world life's not like that unless you have a standard Caterham. However you can get a good comparison. Oh that offers still on if you like small problem I working 7 days a week but normally free PM Sunday's. Plus I not started the car for a long while I must do that very very soon. 'Can you hear me running' ......... OH YES and its music to my ears 😬 😬 😬 1988 200 bhp, 146 ft lbs, 1700cc Cosworth BD? on Weber's with Brooklands and Clamshell wings, Freestyle Motorsport suspension. Q 979 CGY Link to comment Share on other sites More sharing options...
Bilbo Posted January 20, 2003 Share Posted January 20, 2003 Hi Well having checked the diameter of my 205/60/13 seems the rolling diameter used in the calculator was wrong. Not sure why? Must be a typo error.... big opps not sure if it was me at the moment 😳 Still it makes my postings on speeds a load of old Crap 😳 I will mod the whole of the previous lot ..... err tomorrow. 'Can you hear me running' ......... OH YES and its music to my ears 😬 😬 😬 1988 200 bhp, 146 ft lbs, 1700cc Cosworth BD? on Weber's with Brooklands and Clamshell wings, Freestyle Motorsport suspension. Q 979 CGY Link to comment Share on other sites More sharing options...
RiF Posted January 21, 2003 Author Share Posted January 21, 2003 Thanks for the invite Bilbo, Glad to hear I am not the only one still confused Richard in France five weeks to go before delivery of chassis to start building my Duratec 7 😬 Link to comment Share on other sites More sharing options...
Bilbo Posted January 21, 2003 Share Posted January 21, 2003 Hi Peter Well I have been correcting all the previous for the correct rolling diameter now our figures are similar. I miss-typed the figures for the tyre diameter and saved them. 😳 I should have known it was me I think I will get out in the car and find out what the TRUE maximums are before going any further. I suspose in reality the max power rev is more the true top speed. Must be nice to have data logging and a stack dash and know for sure the reality. 'Can you hear me running' ......... OH YES and its music to my ears 😬 😬 😬 1988 200 bhp, 146 ft lbs, 1700cc Cosworth BD? on Weber's with Brooklands and Clamshell wings, Freestyle Motorsport suspension. Q 979 CGY Link to comment Share on other sites More sharing options...
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