mcerd1
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| posted on 25/6/10 at 08:57 PM |
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quote:
Originally posted by BenB
quote:
Originally posted by mcerd1
that'd be 5400rpm in 5th then - which seems a bit high too not be in the power band
ever had the car on the rollers ?
Or even 4500 in 5th 
oh b*****ks, I getting confused already - edited above...
[Edited on 25/6/2010 by mcerd1]
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mcerd1
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| posted on 25/6/10 at 09:04 PM |
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quote:
Originally posted by deltron63
quote:
Originally posted by mcerd1
btw - I can have a go at working out your diff ratio for you if you tell me what size your rear tyres are
185/65/14 i think?
well based on the above I recon that either a 4.9 or a 5.1 ratio (I think those are standard english axle ones)
thats a fairly low gear ratio 
could be a bit more sure if you had a few more 'rev+gear=speed' figures
[Edited on 25/6/2010 by mcerd1]
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deltron63
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| posted on 25/6/10 at 09:09 PM |
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what would be the best ratio?
anyone got a diff 
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mcerd1
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| posted on 25/6/10 at 09:16 PM |
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download this gear calc program and have a play linky
In general the lower the ratio the better your acceleration, but the faster you run out of gears/revs
most of these programs assume you have unlimited power (this one included) so won't allow for the areodynamics that will limit your top speed in
real life
instead its best to look at the speeds you know you can or should be able to achive and see what revs you'll be doing in each gear at a give
speed
then compare that to a print out from the rolling road and you might start to see where the problems are.....
(assuming they don't find your problem on the rollers)
[Edited on 25/6/2010 by mcerd1]
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deltron63
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| posted on 25/6/10 at 09:20 PM |
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cheers i'll give it a go
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paulf
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| posted on 25/6/10 at 09:21 PM |
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I have a 3.89 diff in my car and it pulls fifth gear from 30mph up to 120mph although it is a 2 litre.The 1.8 I had in it was not as torquey but
still managed 115 to 120mph in top.This is with 185/60/13 tyres.
You will probably benefit from a rolling road session to set the carbs and ignition correctly.
Paul
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mcerd1
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| posted on 25/6/10 at 09:23 PM |
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just a though - are you running a 3D map on the megajolt ?
if you are is it off a MAP sensor or a TPS ?
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deltron63
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| posted on 25/6/10 at 09:56 PM |
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quote:
Originally posted by mcerd1
just a though - are you running a 3D map on the megajolt ?
if you are is it off a MAP sensor or a TPS ?
3d map with tps
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Danozeman
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| posted on 26/6/10 at 11:19 AM |
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My 1.8 with bike carbs and megajolt and 3d map. Type 9 and 3.44 cortina diff pulls in 5th from 60 to over 120. No where near aswell as if i drop it
to 4th or even third but it does go. You can tell the difference over 90 when the coming wind is like a wall.
If the calc for your diff is right then you need a different one.
Dan
Built the purple peril!! Let the modifications begin!!
http://www.eastangliankitcars.co.uk
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deltron63
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| posted on 26/6/10 at 06:08 PM |
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i went out today, i think it must be fuelling.
pulls from 30mph no problem, then plays up at 80.
i hope another jet hasn't fallen out!!
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iank
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| posted on 26/6/10 at 07:57 PM |
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The engine doesn't know how fast you are going only the rpm it's doing, as the rpm in 4th at 110mph is going to be more than 5th at 80mph
it would seem able to rev properly.
Does it struggle in 4th around 65mph? i.e. there's a big dip in the power curve.
--
Never argue with an idiot. They drag you down to their level, then beat you with experience.
Anonymous
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deltron63
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| posted on 26/6/10 at 08:23 PM |
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quote:
Originally posted by iank
The engine doesn't know how fast you are going only the rpm it's doing, as the rpm in 4th at 110mph is going to be more than 5th at 80mph
it would seem able to rev properly.
Does it struggle in 4th around 65mph? i.e. there's a big dip in the power curve.
nope only in 5th
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