Bruntingthorpe today 156mph

So why did my car only manage 156mph today at VMAX ??

Whatever I did, 156mph every time.

With passenger, without, TCS on/off, wing mirrors folding in/out.

All 7 high speed passes were 156mph, I just ran out of power, I know the weather was not ideal, absolutely sweating with not even a breeze but still.

Anyway a few pictures of the metal on show :)

http://snap25.photobox.co.uk/3383486...80e3a59a6d.jpg

http://img.photobox.co.uk/1903699554...1a22a90ee3.jpg

http://snap28.photobox.co.uk/4497753...f172db6d70.jpg

http://snap25.photobox.co.uk/6990427...94bbf56aa0.jpg

http://snap28.photobox.co.uk/0459471...782a8e341a.jpg

http://snap25.photobox.co.uk/7029322...9abf5344cf.jpg

http://snap25.photobox.co.uk/4310174...50396e7f85.jpg

well done matey :wink:

156 is not bad!!!!! 8)

Thats a good speed mate. At Elvinton I managed 162mph in 1.25 mile but my car had no cats and an aftermarket exhaust. How long was the run. I think the cats removed allows the engine to run more free at high speed. Maiby wrong though.

So.... what sort of speeds were you reaching in say 4th?

I didn't check speeds in gears unfortunately :(

It was a very hot day so that didn't help, especially as the runway is 2 miles.

Funnily I ran later that afternoon (was busy taking photo's, then playing with Bens M Roadster, and finally had to dash up to Kwik-Fit for new pair of rear tyres after a puncture (£££OUCH£££!)). Guess what? Yes, 156mph. As I mentioned I suspect my exhaust is liberating a little more grunt - possibly to 3.2 levels - but thats still down on my 160mph best. Everyone commented on being 4-5mph down on previous best.

FWIW fastest in the Z4M was 152mph.... (although it was easily the most sideways :twisted: )

Could the air temperature be a factor?

Warm air is less dense than cold and releases fewer horses.

Mo

That's what I am thinking, either that or it takes more than 2 miles for an NSX to get to VMAX. I have had the car further round the clock than that before so it could have been anything really.

Quote:

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Originally Posted by modarr

Could the air temperature be a factor?

Warm air is less dense than cold and releases fewer horses.

Mo

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Hi Simon,

Was the 156mph what was measured on your car's speedo, or is it some kind of digital/gps reading?

156 sounds questionably and unbelievably much much too low...especially when some people have seen 187 on their speedo on stock 3.0 litres.

Cheers,
Martin

156 was using the speed trap equipment they had, it was a very warm day though and only a 2 mile runway with a lot of heavy dead air. It really was like a swimming pool.

1 other NSX (trackdemon) also managed only 156 with a 3.0 car and aftermarket exhaust.

Quote:

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Originally Posted by Martin

Hi Simon,

Was the 156mph what was measured on your car's speedo, or is it some kind of digital/gps reading?

156 sounds questionably and unbelievably much much too low...especially when some people have seen 187 on their speedo on stock 3.0 litres.

Cheers,
Martin

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Did any car there achieve more than 156 on the day? Just trying to rule out equpiment failure (possibly software related).

156 might have been the highest that the hardware could register or display.

Richard

192 RUF GT2 Nardo
191 SL600 Kleemann (184 roof down)
189 996TT DMS/Andy Fearns
184 993 RUF Turbo
183 GT2
183 993TT Earl of Bolton Spec.
183 996TT X50
183 993TT RS Tuning
182 996T X50 with aerokit
178 996TT
176 AM DB9
176 Gallardo Spyder (roof down, not maxing it)
176 996TT
173 Audi S4 modified
173 996TT cab (164 roof down)
167 F360 spider
167 993TT
166 CL65 AMG (engine problems, already at dealers)
166 F355 Berlinetta
164 SLK55 AMG
158 E46 M3
156 NSX 3.2
156 NSX 3.0
156 rx-7 turbo
154 996 C4
153 Supra TT
153 535D
153 Noble Tronspec (minus intercooler fan)
152 Z4M
150 993 C2
150 Z3M
144 3.2 Carrera
140 TVR Chim400
140 Lexus LS430
139 Lotus Exige S2
136 Golf R32
135 Imprezza Estate
123 mk3 Golf GTi 16v

Myself and Andrew Barwick spent a day at Bruntingthorp a while back. Track was all to ourselves! Anyway, he tried some max speed runs, and got fairly similar to 156 if I remember correctly. This was going around the circuit and getting a run up onto the straight.

Oh this was in winter, and it was freezing cold.

I saw 150mph on an uphill section of motorway in my last NSX(3.0L) so i would be supprised if 156 is all they give.

I've had my clock (maybe not that accurate) showing 164mph on a cool night over about a 2.5 mile stretch of road. Thats in bog standard trim, 1992 3.0L manual and with a passenger on board. Might have to pick my time with the new set-up to try again. I'll have to borrow my mate's Tom Tom Sat Nav to try and get a more accurate speed reading. I thought they should be good for 170mph+? Or am I just dreaming?

IMO 165mph is genuine max in my 3.0 manual - 160mph is the fastest I've seen at VMAX and it was the same through the traps and on the speedo so I'm inclined to think the 167mph I saw on the speedo *on a private track of course* in France is just about spot on as real VMAX. I'd be surprised if a standard 3.2 managed more than a 170mph - certainly the allusions to 180mph+ are pie in the sky, I'd happily bet £10k that a standard NSX cant do that speed (on the flat, no wind etc.) considering that genuine 180mph+ cars tend be nearer the 400bhp mark.

Quote:

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Originally Posted by trackdemon

IMO 165mph is genuine max in my 3.0 manual - 160mph is the fastest I've seen at VMAX and it was the same through the traps and on the speedo so I'm inclined to think the 167mph I saw on the speedo *on a private track of course* in France is just about spot on as real VMAX. I'd be surprised if a standard 3.2 managed more than a 170mph - certainly the allusions to 180mph+ are pie in the sky, I'd happily bet £10k that a standard NSX cant do that speed (on the flat, no wind etc.) considering that genuine 180mph+ cars tend be nearer the 400bhp mark.

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I think i would agree with you regarding the VMAX.I read somewhere on prime that a stock 3.0L was timed with gps at 168mph

Well all I know is that Bentley Continental GT's shouldn't bother against an NSX. :lol:

that pic is from an american Acura NSX

here's one from an almost stock 3.0 UK NSX
(car owned and photo taken by one of our members here)

http://nsxcb.co.uk/forum2/files/nsx_187_982.jpg

I do wonder if the top end is directly related to how the car has been driven throughout its life. My NSX feels very spritely and now its got better breathing the throttle response is even better. I am however the 9th, yes 9th, owner. I dare say that the first couple of owners may have looked after the car but I dare say each person has had their fair share of 'fun'. Perhaps the different speeds people seem to be getting is partly down to how loose the engine is. Maybe a few more BHP are released?

Just a thought . . . .

I guess this must be an NA2 then as it says it's in 5th gear ??

click for pic

Quote:

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Originally Posted by Speedy Gonzales

Posted by John McCain Racing NA1 6 speed. This car has a list of mods.

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including the same gearbox, LSD & R&P as me ;)

....another :?: ....what effect would it have on your top end speed by installing the 4.44 R+P?

NSXs with std sized rear tyres - 225/50/16 91-93 and 245/40/17 94-01, which do 811 and 816 revolutions per mile respectively are geared to theoretically achieve the following:

91-93 = 189.0 MPH
94-96 = 187.8 MPH
97-01 = 201.1 MPH

whilst the car may be geared to be able to reach these speeds, the limiting factor is the wind resistance or drag, which increases on an exponential curve to rather massive amounts at these higher speeds, and the actual limiting factor is that the car does not have sufficient power to push through this opposing force.

this is the reason that better results are obtained downhill and/or with a following wind, both of which help to push through the drag a little bit.

of course by increasing the power that the car can put out you can make further inroads towards these potentially attainable higher speeds, but remember, when you look at a power curve you will see that peak power is usually a few hundred rpm below the redline, so since you really need all that power to get through the drag, and as soon as the power begins to wane you will stop accelerating through it, the real world figure to use for RPM is not in fact the max of 8000, but wherever your peak power is being made.

example dyno maps (showing wheel horsepower) are shown here:

first an N/A NSX, then a Turbo, then a Nos'd

http://www.nsxprime.com/FAQ/Performa...dhdynoday1.jpg
http://www.nsxprime.com/FAQ/Performa...msdynoday1.jpg
http://www.nsxprime.com/FAQ/Performa...avdynoday1.jpg

you'll note that all 3 see power drop away after 7800 rpm, so the real world acheivable top speed should be measured from 7800 rpm despite the car being geared to achieve a greater speed in a world without wind resistance or the need to generate the power to overcome it.

at 7800 the speeds acheivable on std tyre sizes assuming that we can overcome drag are:

91-93 = 184.3 MPH
94-96 = 183.1 MPH
97-01 = 196.1 MPH

but as you increase the size of the rear tyres (and lose acceleration and handling) you increase theoretical top speed

e.g. my rear tyres are 255/40/17, which have a revs per mile figure of 806, so if my final drive were standard my theoretical top speed (TTS) would be 185.4 at 7800 rpm.

however my final drive is 4.4:1 (std is 4.062:1), so this changes my TTS to 171.2 MPH at 7800, or since air resistance is much less at this speed I might be able to push on through towards 8000rpm for a speed of 175.5 MPH

the resources you need to work out your theoretically achievable speed at any given revs in any given gear are as follows:

chosen RPM - just pick one
ratio of chosen gear - see ratios chart below
ratio of final drive - select as appropriate
revolutions per mile of your rear tyres - work it out here


gear ratios:

Japan 3.0
1st = 3.071
2nd = 1.952
3rd = 1.400
4th = 1.033
5th = 0.771

rest of world 3.0
1st = 3.071
2nd = 1.727
3rd = 1.230
4th = 0.967
5th = 0.771

all 3.2's
1st = 3.066
2nd = 1.956
3rd = 1.428
4th = 1.125
5th = 0.914
6th = 0.717

final drive ratios:
all std NSXs = 4.062:1
JDM Type-R = 4.235:1
OS Giken = 4.4:1
Comptech = 4.55:1


the equation to use is this:

divide your rpm by your gear ratio
divide the result by your final ratio to get wheel revs per minute
divide the result by your tyre's revs per mile to get mile per minute speed
multipy the result by 60 to get MPH

if anyone is still awake after all of that, I knocked up an excel spreadsheet with all the formulae pre-populated for you - you just have to enter the variables specific to your chosen/desired setup and the TTS will be displayed - you can download it from here

EDIT - REVISED VERSION NOW AVAILABLE - CLICK HERE TO DOWNLOAD

~Judging by the sppeds I have had out of mine in 4th and the general 30mph in each gear pattern I see goin up through 2nd, 3rd and 4th I woudl say that 180+ would be reached in my 3.2 -if only I had the roads to take it there!

Had an interesting race with a Ducatti 999s, was up my ar5e all the way but didn't take me.. maybe he could have if he weanted to!?

well there are 2 photo's of it happening further above in this thread and a comprehensive explanation of the theory just above also, so I can't see why not.

I've only seen 165 MPH in mine in std configuration at 7000rpm (uphill!) before I bottled and eased off - checking that against the spreadsheet the numbers are bang on (164.3 MPH actually). the car was still pulling strongly when I eased off and I felt confident that it would have made it to the redline ok, which would have placed it at 187.8 MPH if I had kept my foot in.

having discussed in person the speed shown in the 2nd photo above with the owner who took the photo, I have every confidence in the credibility of that being an accurate indication of the speed achieved in an UK 3.0 NSX.

this link might be useful for those interesting in the more technical aspects of this thread

clicky the wiki

and in case you didn't notice my edit on the previous page, my gear ratio calculator has been updated and can now be downloaded from here

http://darrenferneyhough.com/ratios.xls

I think that another reasonably fair method of extrapolating the NSX's real top speed (I still stand by 165mph) is to compare to other cars of similar power...

3.0 & 3.2 NSX's have under 300bhp as standard (270-286bhp, depending what you read), the fastest 300bhp car I can think of is probably the Porsche Cayman. A Cayman S with 295bhp & better aero (than NSX) has a top speed of 171mph, a '97 993 with 285bhp 167mph. A 997 with 325bhp is quoted at 177mph, and the base 997 is a very slippery shape..... so you see I can't understand how an NSX can do the 180mph+ that some are claiming.

I took my old 3.2 down the Autobahn at Easter and it made an indicated 174mph and though it was moving very slowly in the up direction, holding a car on WOT for long periods is not my cup of tea, so that was effectively top speed for me. It was never going to make 180 without the help of a good gradient.

I reckon the speedo is reasonably accurate but I never had my B2 in the car for comparison. I Assumed it was really somewhere approaching 170, which I feel is about right for the car.

trackdemon - where oh where to begin my dear boy...

....it is true that a Cayman has a Cd figure of 0.29 which is better than the 3.2 of the early NSXs and also better than the 3.0 of the facelift version. (Although interestingly this applies only to the manual version - the tiptronic is 3.0)

however, drag is not measured by the cd figure alone;
the formula for air drag is Cd x frontal area

for the NSX, which has a frontal area of 1.78 sq.m, the air drag coefficient is:

1991-2001 models - 1.78 x 0.32 = 0.5696
2001+ models - 1.78 x 0.30 = 0.5340

compare this with the air drag coefficient of the Cayman with it's frontal area of 1.98 sq. m:

1.98 x 0.29 = 0.5742

so the air drag of the Cayman S is marginally higher than the early NSX and significantly higher than the late NSX, so has to work harder to punch through it at higher speeds than our baby ;)

of course, it's weight of 1415kg compared to 1392kg on the early coupe's and 1340kg on the later ones is another disadvantage it's available power has to overcome on the way to reaching it's top speed, which the manufacturers spec sheet puts at 171MPH

at 295hp the Cayman S has basically the same amount of power as the NSX actually has, although the 'gentlemens agreement' means the NSX's stated figure is 276hp (280PS).

so we have established the following:

1. the Cayman S has roughly the same power as the NSX
2. the Cayman S has greater air drag to overcome than the NSX
3. the Cayman S has more weight to move than the NSX

so the chips really are stacked against the Cayman S in acheiving a higher speed than the NSX as the above demonstrates, but what of the Cayman's gearing?

well, it has a 6th gear ratio of 0.82 and a final drive of 3.88. with the driven wheels wearing 265/35/19 rubber (767 revolutions per mile) and peak power at 6250rpm.
the speed at this point would be 153MPH and through the remainder of the rev range up to the redline of 7200rpm it is making less power than it's earlier peak of 295hp (back at 153MPH), so it really is quite an acheivement to get to 171MPH with the power dwindling from 153 onwards.

so, when the Cayman is making it's peak power (whether you believe it is more than an NSX makes or not), it is doing so at a time when it is not needed (in terms of best overcoming air drag), and at the time when it does need the most power it can make, it is already spent :(

conversely, because of our lovely VTEC engine, the NSX is making peak power (lets call it 290hp eh?) at 7800rpm, where it's gearing allows for acheivable speeds in the 3.0 and 3.2 of 183MPH and 197MPH respectively.

whilst I can't see the 6-speed getting to 197MPH without serious power upgrades, the 5-speed seems to have it's ratios and power delivery matched perfectly to allow the driver to maximise all the potential behind and under him, and with a following wind and/or downhill run possibly keep on accelerating beyond the peak power delivery at 184MPH to the maximum geared speed at redline of 187+ (of which there are 2 pieces of photographic evidence posted in this very thread).

so the NSX has:

1. more power (at the appropriate speed/revs)
2. less weight to carry
3. less drag to overcome

than the 171MPH Cayman S - is it any surprise that it has a higher top speed?

not to me ;)

I'm sure you can see why the NSX is so often underrated and underestimated by those who do not fully understand how the numbers work together, as it is very easy to see certain numbers which look better in isolation but in a practical application still add up to less.

for those who might want to crunch the numbers, you get speed from gears/tyres by the following equation:

engine revs / gear ratio / final drive ratio / tyre revs per mile x 60

Quote:

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Originally Posted by Minch

I've had my clock (maybe not that accurate) showing 164mph on a cool night over about a 2.5 mile stretch of road. Thats in bog standard trim, 1992 3.0L manual and with a passenger on board. Might have to pick my time with the new set-up to try again. I'll have to borrow my mate's Tom Tom Sat Nav to try and get a more accurate speed reading. I thought they should be good for 170mph+? Or am I just dreaming?

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Lots of nice goodies there. :mrgreen:

the NSX tach reads 1-2% HIGH, I don't know what the speedo error is, but you can figure out what the POTENIAL top speed is by doing the gear ratio X the RPM X the tire diameter etc calculations. (don't forget that the guys running 4.23 or 4.44 or 4.55 will have lower top speeds)

there is a chart on Prime that shows that.

Ways to go faster:
lower the weight
lower the height
remove excess wings and etc
have thinner tires
HAVE LOTS MORE HP :mrgreen:

the chart on prime is located here:

http://www.nsxprime.com/FAQ/Technical/gearratios.htm

Quote:

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Originally Posted by simonprelude

So why did my car only manage 156mph today at VMAX ??

Whatever I did, 156mph every time.

With passenger, without, TCS on/off, wing mirrors folding in/out.

All 7 high speed passes were 156mph, I just ran out of power, I know the weather was not ideal, absolutely sweating with not even a breeze but still.


http://snap25.photobox.co.uk/6990427...94bbf56aa0.jpg

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I think I know what the problem was Simon - the grassy surface was obviously keeping you from getting all your power down effectively - next time try it on the tarmac mate ;)

Why do i nearly always see the top speed quoted for the 3.0L as 158mph :(

Isn't Senna Driving the NA1 in this video around Susuka at 180 MPH around minute 2.00 ?

http://video.google.co.uk/videoplay?...702526&q=senna

Cheers

AR

Quote:

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Originally Posted by AR

Isn't Senna Driving the NA1 in this video around Susuka at 180 MPH around minute 2.00 ?

http://video.google.co.uk/videoplay?...702526&q=senna

Cheers

AR

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It's a JDM car.so it would be KPH not MPH,but i don't think there is a road car in the world which would get up to 180MPH on a circuit anyway.

Damm,Darren.

You should oughta start writing a dang book on the car. You da man wid da big phat NSX brain

I just love the detail, great reading. The NSXGB forums are like University Challenge compared to the Celebrity Love Island level of the other retard forums I'm on.

I feel like writing my kids a quick apology for ruining their future prosperity and getting the car out for a couple of laps of the M25-o-ring just to put this one to bed.

Mo

thanks Mo - nice to be appreciated :D

ctrlaltdelboy - my retort 'dear boy'

I concede that the 'overall' aerodynamic drag of the NSX may be lower than the Cayman taking into account frontal area - I really ought to have taken this into account! I'd be interested in your data sources though - I couldn't find anything concrete through an admittedly brief google session.

There is no concrete data to prove the NSX power output is anything more than that stated by the manufacturer, so until proved otherwise I'll stay with 286bhp at most.

Weight has little bearing on top speed, a 120bhp/750kg Elise tops around 124mph, and a 113bhp/1125kg MINI Cooper tops around 125mph (source Autocar). Nonetheless, Autocar quote NSX 3.2 @ 1320kg & Cayman S @ 1340kg - insignificant.

There is no supporting evidence which states the Caymans power curve drops off after peak power at 7200rpm; chances are (and this is surely borne out factually by the Caymans S top speed) the power output stays more or less level from then through to cutout.

I do believe the Cayman develops more bhp than an NSX, this conclusion is drawn both from on paper stats (and my interpretation thereof) and actually driving the 2 cars back to back.

So:

1. The Cayman has more power (proven, on paper, factually quoted)
2. Almost exactly the same weight (which has little effect on top speed anyway)
3. Alleged marginally more drag, although sources unquoted

So @ 171mph - speed is higher just as I would expect.

If someone can prove their factory spec NSX is capable of 180mph or more in normal circumstances then I'll happily eat a Honda hat. Otherwise, claims of realistic 175mph+ capability remain poppycock IMHO.

For the purpose of adding balance - people never cease to be impressed my my NSX's acceleration and speed capabilities when they experience it; I am certainly not underestimating NSX performance rather just trying to add a degree of realism to the discussion.

Think you're right Darren.

Just to add to your foot note. I must agree that out of all the high performance cars I've had the pleasure to drive the NSX has got a very good throttle response/acceleration. The only other car which I would say had better response was the Elise, mainly due to the fact that it weighed about the same as an obese ant!

Great car and loving the new mods :D (which has also improved the throttle response further!!!)

cool - a proper debate :D

re the air drag/frontal area - the frontal area of the NSX and all figures for drag and lift are detailed in the Honda spec sheet here (for the early 3.2)

the frontal area of the Cayman is harder to find (as I see you found out!), but some clues can be found here:
http://www.carfolio.com/specificatio.../id/?id=132913
http://www.carfolio.com/specificatio.../id/?id=133903

re the power thing - NSX stated power is 280PS which is equivalent to 276BHP - not sure where you're getting the 286 from.
measured power at the wheels across a variety of different NSXs is viewable on the dyno charts in this document which came out of the NSXPrime Dyno Day in 2002

re cayman power not dropping during the remaining rpm range after peak power is first acheived - I guess some dyno charts would be interesting to look at in answering this one, so I did some searching and on initial research this would appear to be the case:

http://www.caymanregister.org/UserFiles/dynochart.jpg

the above chart shows 269HP at the wheels, compared with the charts from the NSX shoot out showing 252-267HP with non-standard exhausts and 237-267HP with zero or air filter only mods

so as I said before, these 2 cars are definately in the same ball park for power.

re the weight thing, sorry - there are 2 sets of weights bandying around, I quoted the weight from carfolio (above) which is as declared by Porsche under the EC Directive, rather than the DIN weight which they declare as 1350kg (see here) - anyone know what the difference between the 2 different weights is? (or for that matter what consitiutes 'kerb weight' as often used by manufacturers)

1350kg is exactly the same as the original NSX, although the NSX has shed weight since as shown in this diagram:

http://www.honda.co.jp/factbook/auto...img/09_p02.gif

more detail on NSX weights (in English!) can be viewed here for the early 3.2, here for the facelift 3.2 and here for the NA2 NSX-R


re the speed thing - I consider multiple examples of photograhic evidence, one of which came from a member here (with a gps verified speedometer) who I have known and respected for some years and whose honesty I don't doubt, to be evidence enough.
My belief in the truth of acheivable 187mph is bolstered by my own experience (again gps verified speedo) of 165mph uphill at 7,000 rpm and still pulling strong before losing my bottle.


so if there is no real weight difference (and you claim it is not a factor anyaway) and no real power difference (at least at the higher end of those NSX's tested) and both cars are geared to see speeds higher than the manufacturers' stated maximum, the only differentiating factor between them in attaining a higher speed is the limits imposed by air drag or mechanical gearing.

the Cayman S with standard gears and tyres is geared for 177MPH maximum and fighting a Cx figure of 0.5742 to get there due to it's frontal area of 1.98m2

the 5 & 6 speed NSXs are geared for 183 & 197MPH maximum and have a Cx of 0.5696 & 0.5340 to fight against.

I think the evidence is sufficient to demonstrate that the NSX in all forms should, can and does outdrag the Cayman S.

what is most interesting to me is the difference between all the NSX dyno results with stock or close to stock setups.

this variation could be the very reason why some members have seen 180+ while others no more than 156?

however, all of this is relativlely moot for me, as my gearing will only allow me to get up to 171MPH anyway :)