Discussion
I know of a couple of S2's that have reached 135mph+ , I tried this a few years ago at 2am on a dual carrigeway and managed an indicated 140 with a bit left (unlike the road I was on!) which meant the speedo was probably out a bit, another friend of mine did the same but was equipped with some sort of GPS device and it indicated 140.5 I believe.As for the original road tests where you get the 130 top speed, well they seem strange to me as a 2.8i Capri will do this but weighs more?? (surely a Capri is not more aerodynamic?), maybe the temp guage was in the red or the fuel guage was registering empty or the throttle pot had gone 
maybe we have larger balls!.I must just point out though that when I tried this it was very early in the morning so the road was 90% empty and I did know the road quite well, things come up very very quickly at this kind of speed and an S is very seat of the pants compared to these modern cars that dull the senses (my knuckles were white for a month!).Go careful
Cheers
LeeBee
maybe we have larger balls!.I must just point out though that when I tried this it was very early in the morning so the road was 90% empty and I did know the road quite well, things come up very very quickly at this kind of speed and an S is very seat of the pants compared to these modern cars that dull the senses (my knuckles were white for a month!).Go careful Cheers
LeeBee
quote:
Over to you Harry, I'm to busy with the calculator !!!
Blimey, quit whilst your behind comes to mind, so does wind you neck in harry
Without getting the slide rule out, I wouldn't have thought that a difference in ratio's of 3.62 to 3.64 would make the sort of difference we're talking here Jas, I obviously do not have the depth of experience you have on this matter
so I bow to your superior knowledge on this subject. I therefore believe (back peddle smiley would be nice here ted) the tables in the bible must be wildly out for the V6 S given that for 60 profile tyres it states that 6000 rpm = 166mph
LeeBee again quoting the bible
which in turn quotes What Car Aug 1989 as 131mph, don't give me a hard time as well about this 
speak to Shpub 
as I believe my source material is suspect. Harry
P.S. Silly really as I would normally make no assumptions in work, believing that assumptions are normally the mother of all F*ck ups.
Thanks Guys for the initial responses to my speedo query, and sorry for the delayed response.
This thread has taken some interesting turns since I last looked at it, but I am intrigued by the posts about maximum speed.
I have certainly seen 135 indicated as, not knowing any better, I drove at or around this speed from Frankfurt to Dusseldorf. (I thought S's were supposed to be capable of these sort of speeds, cos it said it in the advertising blurb). I don't remember the exact RPM, but there was quite a bit to go to the red line, so I assumed that the speedo over read and guessed I was probably seeing high 128-130ish. Only problem I had was when I foolishly opened the airvent and got a faceful of grit/leaves etc.
Cheers
Graham
This thread has taken some interesting turns since I last looked at it, but I am intrigued by the posts about maximum speed.
I have certainly seen 135 indicated as, not knowing any better, I drove at or around this speed from Frankfurt to Dusseldorf. (I thought S's were supposed to be capable of these sort of speeds, cos it said it in the advertising blurb). I don't remember the exact RPM, but there was quite a bit to go to the red line, so I assumed that the speedo over read and guessed I was probably seeing high 128-130ish. Only problem I had was when I foolishly opened the airvent and got a faceful of grit/leaves etc.
Cheers
Graham
OK
The 3.64 diff ratio came from TVR but could be a typo and is actually 3.62 however, the diff internals are pretty wierd and so who knows. Some have the internals from European Ford special that was only made in for the outer Mongolian market cars with a 4.5 cylinder diesel three stroke engine as a part of an unfinished government contract for Aeroflot. It makes 0.005% difference so in all honesty you would be better off worrying about how much tread was on the tyres.
As for pulling 6000 rpm in top gear... I don't think so. Not unless you are going downhill rapidly... as in falling off a cliff downhill rapidly and even then I suspect the terminal velocity is still only around 145-150. The gearing says yes but the aerodynamics limit the car to around 140 ish. Quit common for both speedos and rev counters to be wildly out at these speeds. I do know of stange goings on when an 8 cyl rev counter is fitted to v6 cars and vice versa and they can simply be inaccurate. So pulling 6000 in 5th might actually be pulling 5000 real rpm which is about right. As can the speedos. The 390 speedo was OK upto 60, lost 5-10 mph upto 90 and then wouldn't go any higher. I'm pulling 6000 rpm in fifth at Goodwood and the speedo says about 90! Replaced with a digital unit that is accurate to about 1 mph. Ish.
Steve
The 3.64 diff ratio came from TVR but could be a typo and is actually 3.62 however, the diff internals are pretty wierd and so who knows. Some have the internals from European Ford special that was only made in for the outer Mongolian market cars with a 4.5 cylinder diesel three stroke engine as a part of an unfinished government contract for Aeroflot. It makes 0.005% difference so in all honesty you would be better off worrying about how much tread was on the tyres.
As for pulling 6000 rpm in top gear... I don't think so. Not unless you are going downhill rapidly... as in falling off a cliff downhill rapidly and even then I suspect the terminal velocity is still only around 145-150. The gearing says yes but the aerodynamics limit the car to around 140 ish. Quit common for both speedos and rev counters to be wildly out at these speeds. I do know of stange goings on when an 8 cyl rev counter is fitted to v6 cars and vice versa and they can simply be inaccurate. So pulling 6000 in 5th might actually be pulling 5000 real rpm which is about right. As can the speedos. The 390 speedo was OK upto 60, lost 5-10 mph upto 90 and then wouldn't go any higher. I'm pulling 6000 rpm in fifth at Goodwood and the speedo says about 90! Replaced with a digital unit that is accurate to about 1 mph. Ish.
Steve
OK I'm confused now... (easily done)
Why won't the car do 6000rpm in 5th..? My Puma (granted a newer car, but heavier and with a smaller engine) will do 6250rpm and 130 quite happily with its lower ratio box of 21mph per 1000rpm and would go more but for the limiter.... what is the technical limitation stopping the S doing 6000rpm at 138? Aerodynamics only?
..or are we convinced that 6000rpm is 166mph..??
Cheers
Matt
(easily done) Why won't the car do 6000rpm in 5th..? My Puma (granted a newer car, but heavier and with a smaller engine) will do 6250rpm and 130 quite happily with its lower ratio box of 21mph per 1000rpm and would go more but for the limiter.... what is the technical limitation stopping the S doing 6000rpm at 138? Aerodynamics only?
..or are we convinced that 6000rpm is 166mph..??
Cheers
Matt
quote:
OK
The 3.64 diff ratio came from TVR but could be a typo and is actually 3.62 however, the diff internals are pretty wierd and so who knows. Some have the internals from European Ford special that was only made in for the outer Mongolian market cars with a 4.5 cylinder diesel three stroke engine as a part of an unfinished government contract for Aeroflot. It makes 0.005% difference so in all honesty you would be better off worrying about how much tread was on the tyres.
As for pulling 6000 rpm in top gear... I don't think so. Not unless you are going downhill rapidly... as in falling off a cliff downhill rapidly and even then I suspect the terminal velocity is still only around 145-150. The gearing says yes but the aerodynamics limit the car to around 140 ish. Quit common for both speedos and rev counters to be wildly out at these speeds. I do know of stange goings on when an 8 cyl rev counter is fitted to v6 cars and vice versa and they can simply be inaccurate. So pulling 6000 in 5th might actually be pulling 5000 real rpm which is about right. As can the speedos. The 390 speedo was OK upto 60, lost 5-10 mph upto 90 and then wouldn't go any higher. I'm pulling 6000 rpm in fifth at Goodwood and the speedo says about 90! Replaced with a digital unit that is accurate to about 1 mph. Ish.
Steve
The rev counter definitely read 6000rpm and the speedo read 120mph. It was down a hill not off a cliff though !!
Interesting debate !!
One of the differences is the choice of tyre: if you use a 205/60/15 (original fit) compared to a 205/50/15 there is quite a difference in gearing and this effectively means that the car is lower geared and this is why it can pull 6000 rpm in fifth.
I think the titles for the V6 and V8S columns have got transposed (but exactly how I'm not sure as it is linked Excel spreadsheet so that I can't make any transcription errors).
Steve
I think the titles for the V6 and V8S columns have got transposed (but exactly how I'm not sure as it is linked Excel spreadsheet so that I can't make any transcription errors).
Steve
quote:
One of the differences is the choice of tyre: if you use a 205/60/15 (original fit) compared to a 205/50/15 there is quite a difference in gearing and this effectively means that the car is lower geared and this is why it can pull 6000 rpm in fifth.
I think the titles for the V6 and V8S columns have got transposed (but exactly how I'm not sure as it is linked Excel spreadsheet so that I can't make any transcription errors).
Steve
205/60/VR15's for me. They are new one the rear aswell, so carrying plenty of tread, or were before the drive home from Donington yesterday
some nice roundabouts on the way home. Mark
quote:
OK
The 3.64 diff ratio came from TVR but could be a typo and is actually 3.62 however, the diff internals are pretty wierd and so who knows. Some have the internals from European Ford special ...
[anorak]
Both numbers are credible, 48/13 (3.615) and 51/14 (3.643) could fit. But the difference is academic.
[/anorak]
quote:
- snip -
The gearing says yes but the aerodynamics limit the car to around 140 ish. Quit common for both speedos and rev counters to be wildly out at these speeds.
I'm having a bit of trouble understanding why the rev counter doesnt work well at high speed.. afterall how does the rev counter know how fast you are going... 5500rpm in second gear is the same as 5500rpm in fifth gear to the rev counter... Steve, are you saying that the rev. counter is not right at higher revs in all gears??
Cheers
Matt
The rev counter should be pretty darn accurate, since all it is, is a counter which counts the ignition pulses direct from the coil.
(I have never heard of rev counters being innacurate except where, as Steve has said, the rev counter is configured for a different number of cylinders).
Jas.
(I have never heard of rev counters being innacurate except where, as Steve has said, the rev counter is configured for a different number of cylinders).
Jas.
quote:
The rev counter should be pretty darn accurate, since all it is, is a counter which counts the ignition pulses direct from the coil.
(I have never heard of rev counters being innacurate except where, as Steve has said, the rev counter is configured for a different number of cylinders).
Jas.
IME they aren't particularly accurate, after all they're measuring a very noisy analog signal at high frequency and its easy to under/over count pulses. Mine on the V8S has a stepper motor drive which I guess rules out display inaccuracy, but on other cars I've had the cheaper 'moving coil' type was another source of error.
I am getting confusing readings from my speedo/rev counter. 3000rpm = 55mph (in 5th)
. If that's the case my speedo is significantly out . I am running 60 profile tyres so it should be fine. Possibly it's set up for a V8 
?
This might explain why I wizz past everyone in the fast lane and am only doing 60.
. If that's the case my speedo is significantly out . I am running 60 profile tyres so it should be fine. Possibly it's set up for a V8 ? This might explain why I wizz past everyone in the fast lane and am only doing 60
.
Blimey it's getting more convoluted by every post. The switching of the results column's in the bible between the V6/V8 did cross my mind though, but I'd certainly have to dust of the slide rule to prove otherwise, now let me check the TV schedules......
Anyone else got any ideas
Who started this thread any way
Harry
Anyone else got any ideas
Who started this thread any way
Harry
quote:
IME they aren't particularly accurate, after all they're measuring a very noisy analog signal at high frequency and its easy to under/over count pulses. Mine on the V8S has a stepper motor drive which I guess rules out display inaccuracy, but on other cars I've had the cheaper 'moving coil' type was another source of error.
Yeah the stepper ones are good but expensive. I've seen them under reading by over 1000 rpm. I know one Wedge owner who fitted a rev limiter and thought it was broken because it was coming into early compared o the rev counter. Turned out that the rev counter was under reading by 1200 rpm. So when he was changing up at around 5500, the engine was actually doing 6700!
The signal quality problem is an issue with them especially on the V8 cars that have an electronic dizzy which can produce some interesting signals.
Steve
quote:
Blimey it's getting more convoluted by every post. The switching of the results column's in the bible between the V6/V8 did cross my mind though, but I'd certainly have to dust of the slide rule to prove otherwise, now let me check the TV schedules......
Your confused... my originals do have the titles the other way around so I don't understand how they got switched when printing as the printing process is all digital...
The table was taken using the tyre size spread sheet on my website if it will save you time with a slide rule.
steve
www.tvrbooks.co.uk
Shpub
Glad about that I'll put the slide rule back in the museum in the morning
So does that then mean the V8S, assuming no wind resistance, runs out of gears at 166mph
(or 155mph for those of us with the limiter set at 5K6) and the V6 146mph
Re its 'digital' it can't go wrong, we all use MS products in one shape or form, and I think it's fair to say that if that was the case they'd all be 100% reliable, no I don't believe that either
I take it from the possible inaccuracies in the Rev counter (from pickup?) the cable is not screened? Have you every run a screen cable to cure this? I also assume that the EMU/ECU cable must be screened for the limiter to work? implying that TVR have a EMC policy for EMU/ECU cable routing and selection? (probably not)
Harry
>> Edited by HarryW on Tuesday 30th April 00:05
Glad about that I'll put the slide rule back in the museum in the morning
So does that then mean the V8S, assuming no wind resistance, runs out of gears at 166mph
(or 155mph for those of us with the limiter set at 5K6) and the V6 146mph Re its 'digital' it can't go wrong, we all use MS products in one shape or form, and I think it's fair to say that if that was the case they'd all be 100% reliable, no I don't believe that either
I take it from the possible inaccuracies in the Rev counter (from pickup?) the cable is not screened? Have you every run a screen cable to cure this? I also assume that the EMU/ECU cable must be screened for the limiter to work? implying that TVR have a EMC policy for EMU/ECU cable routing and selection? (probably not
) Harry
>> Edited by HarryW on Tuesday 30th April 00:05
Yes.
1. The diff is 3.64. Chceked all the S docs and the Mk2 Granada book and the Sierra book and all say 3.64. Anyway doesn't make any that much difference.
2. Most cars runs out of puff and if they are designed to have an overdrive style top they will certainly have this. Hence the comment that don't expect to see these speeds.
3. The rev counters in the S series are a mismash of components and while they are all digital in that the count pulses, the needle display can be analogue. The point is that people take the rev counter as being 100% reliable... it isn't and is prone to problems but not at the level of the speedo. Sure you can screen the input cable but the noisy signal is more to do with the ignition circuit and the way it is generated rather than EMF generated under the bonnet although there is a lot of that. The 520 had to have screened cable for the traction control intervention loom because of EMF from the multiple ignition coils.
The problem is usually but not always inside the counter itself.
When you get funny top speeds, the natural conclusion is that the speedo is wrong. It might not be as it could be the rev counter and if you are really lucky, even both!
Steve
1. The diff is 3.64. Chceked all the S docs and the Mk2 Granada book and the Sierra book and all say 3.64. Anyway doesn't make any that much difference.
2. Most cars runs out of puff and if they are designed to have an overdrive style top they will certainly have this. Hence the comment that don't expect to see these speeds.
3. The rev counters in the S series are a mismash of components and while they are all digital in that the count pulses, the needle display can be analogue. The point is that people take the rev counter as being 100% reliable... it isn't and is prone to problems but not at the level of the speedo. Sure you can screen the input cable but the noisy signal is more to do with the ignition circuit and the way it is generated rather than EMF generated under the bonnet although there is a lot of that. The 520 had to have screened cable for the traction control intervention loom because of EMF from the multiple ignition coils.
The problem is usually but not always inside the counter itself.
When you get funny top speeds, the natural conclusion is that the speedo is wrong. It might not be as it could be the rev counter and if you are really lucky, even both!
Steve
Firstly, this item must be a record, whats going on!
secondly any of you want to try out your speed (top) i can get a radar gun if you have an airfield. Then you can all attempt to blow your engines up at the same time!
Johno! sent you a pic of my S2 and you will be amazed that it is blue, has the same wheels as both you others and the number plate is nearly the same F867FLG, (well not really) anyone else know my car as i don't have a lot of history with it and it would be nice to find out something. Mind you I've got loads of history in the last 6 months as the work load goes on and on and on...................................
gadgit.
secondly any of you want to try out your speed (top) i can get a radar gun if you have an airfield. Then you can all attempt to blow your engines up at the same time!
Johno! sent you a pic of my S2 and you will be amazed that it is blue, has the same wheels as both you others and the number plate is nearly the same F867FLG, (well not really) anyone else know my car as i don't have a lot of history with it and it would be nice to find out something. Mind you I've got loads of history in the last 6 months as the work load goes on and on and on...................................
gadgit.
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