Topspeed with windscreen lower???
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Topspeed with windscreen lower???
Hi guys,
I’m in a 3.5 sc 310, I’ve noticed that in 6th at 200/210km/u it kinda stops pushing, but my atom 2sc 275 pushed pretty hard at that point, is this due to the windscreen?
Wasn’t able to push any further, but I think to get to 240km/u I need a looooong road.
Any ideas? Or just don’t drive over 200
I’m in a 3.5 sc 310, I’ve noticed that in 6th at 200/210km/u it kinda stops pushing, but my atom 2sc 275 pushed pretty hard at that point, is this due to the windscreen?
Wasn’t able to push any further, but I think to get to 240km/u I need a looooong road.
Any ideas? Or just don’t drive over 200
Re: Topspeed with windscreen lower???
At Spa recently, there were several of us with 310 Atoms and all were getting to around the 240kph mark at the end of the Kemmel, some just over that.
That said, after about 215kph the progress is much slower as the Atom is as aerodynamic as a brick (plus wings create a fair bit of drag too.)
I suspect that the screen is just making the problem more pronounced.
Ditch the screen and go back to the joy of bugs exploding on your visor!
Cheers,
Stu
That said, after about 215kph the progress is much slower as the Atom is as aerodynamic as a brick (plus wings create a fair bit of drag too.)
I suspect that the screen is just making the problem more pronounced.
Ditch the screen and go back to the joy of bugs exploding on your visor!
Cheers,
Stu
- John Scherrer
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Re: Topspeed with windscreen lower???
Thought the windscreen was meant to help ?
Would be a great test to try your top speed at end of straight with and without .. It comes off pretty quickly but this assumes you have the alternate longer bonnet etc.
Would be a great test to try your top speed at end of straight with and without .. It comes off pretty quickly but this assumes you have the alternate longer bonnet etc.
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Re: Topspeed with windscreen lower???
Interesting question - I experienced a rather unscientific event in regard to top speed.
As most of you are probably aware I have recently rebuilt/upgraded my Atom 3.5 310 to the latest 2018 3.5R spec - the day after I picked it up I displayed it at Silverston Supercar Sunday (10th June) and also took part in the parade laps.
During the upgrade I added the full windscreen and ALSO the perpex/polycarbon (clear) side panels with the RT2 multifunction dash.
Despite being briefed that it would be three 'slow' (50mph) parade laps in the event the Track Marshall's McLaren P1 set off like a scalded cat (followed by a further 5 P1s!) I was the 6th car in the snake of approximately 50 supercars and had no trouble keeping up with the P1s on the bends but they generally got away 'a bit' down the straights - however I noticed that on the second lap flat out in 6th gear on the Silverstone start/finish straight the RT2 dash was 'indicating' 160mph (257kph)
Caveat : how accurate the RT2 digital speed display is I have absolutely no idea! - but it certainly didn't do much for the tyres!!
I would, however, point out that my 3.5R has about 50bhp more power than a standard S/c Atom - also it was rather interesting to discover that with the side panels and windscreen fitted it was possible to have an almost normal conversation at 100mph - so I rather suspect the the aero might be considerably improved with these items fitted?
After all there aren't many opportunities to drive an Atom absolutely flat out!
As most of you are probably aware I have recently rebuilt/upgraded my Atom 3.5 310 to the latest 2018 3.5R spec - the day after I picked it up I displayed it at Silverston Supercar Sunday (10th June) and also took part in the parade laps.
During the upgrade I added the full windscreen and ALSO the perpex/polycarbon (clear) side panels with the RT2 multifunction dash.
Despite being briefed that it would be three 'slow' (50mph) parade laps in the event the Track Marshall's McLaren P1 set off like a scalded cat (followed by a further 5 P1s!) I was the 6th car in the snake of approximately 50 supercars and had no trouble keeping up with the P1s on the bends but they generally got away 'a bit' down the straights - however I noticed that on the second lap flat out in 6th gear on the Silverstone start/finish straight the RT2 dash was 'indicating' 160mph (257kph)
Caveat : how accurate the RT2 digital speed display is I have absolutely no idea! - but it certainly didn't do much for the tyres!!
I would, however, point out that my 3.5R has about 50bhp more power than a standard S/c Atom - also it was rather interesting to discover that with the side panels and windscreen fitted it was possible to have an almost normal conversation at 100mph - so I rather suspect the the aero might be considerably improved with these items fitted?
After all there aren't many opportunities to drive an Atom absolutely flat out!
Atom 3.5R (Cyprus)
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- speedmachine
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Re: Topspeed with windscreen lower???
Hi John and Stu, lovely to see you guys are still here
I noticed that this car uncharged had troubles over 210, I thought it would be gone with the charger, but when shifting to 6th it just loses grunt. It’s just the honda saver gear and you notice that.
I’m gonna try and see what km is top speed with and without windscreen, going to Germany end of juli and I will start out with windscreen.
@autobackup: sidepanels does the most I think, as I have almost no wind at all with and about all wind without
I noticed that this car uncharged had troubles over 210, I thought it would be gone with the charger, but when shifting to 6th it just loses grunt. It’s just the honda saver gear and you notice that.
I’m gonna try and see what km is top speed with and without windscreen, going to Germany end of juli and I will start out with windscreen.
@autobackup: sidepanels does the most I think, as I have almost no wind at all with and about all wind without
Re: Topspeed with windscreen lower???
Good to see you back here and congratulations for being back in Atom business
There is a thread somewhere in the forum, stating, that Atoms without windscreen kind of "hit a wall" at a certain speed and from this point further acceleration takes plenty of time.
The big windscreen was said to improve the air resistance, so that acceleration at higher speed would be better.
However this thread also mentioned, that the ram air effect to the air intake would be significantly less when having the big windscreen, which would result in a lack of power at higher speed compared to Atoms with gunsights only.
Whatever may be right or wrong...
From my experience also having the wonderful big windscreen any acceleration beyond 200kph feels a bit time consuming. However this acceleration still is hardly comparable to other cars and my Atom runs 250 quite easily. Admittedly this is according the Spa speedometer and not GPS, but the Atom still accelerates at those speedo 250 and I always had the impression, that I could even hit the limiter in 6th gear.
The 6th gear btw. is no overdrive in the civic, where you hit the limiter at 220kmp (speedo) in 5th gear.
As my basecap does not at all fly away at 250 and because the air appears to nicely be lead over the car I would expect, that an Atom with big windscreen might be slightly faster.
Probably the acceleration at lower speeds is worse because of the higher weight
If your Atom already had problems as n/a I remember a civic, that was not able to exceed 220kph acc. speedo, while all others ran about 245-250 in original spec. This also did not improve by even adding bold-ons like catback and race catalyst. The result on a dyno was about 180bhp(-).
The funny thing about it was, that without changing any hardware between this dyno run and the following ECU adjustment the last dyno after ECU was finally adjusted, showed 220+bhp. So probably a more serious issue with the ECU at that Civic.
As long as you do not have figures to compare the acceleration of your 3-310 and your 2-275 it is perhaps also the missing wind and noise impact, "making" the new one "slower".
I have always remembered, that the passenger drive in your 275 was a lot more spectacular than in my later 300. The driver may had made the difference but I guess you will experience something similar, when you compare driving with and without windscreen.
There is a thread somewhere in the forum, stating, that Atoms without windscreen kind of "hit a wall" at a certain speed and from this point further acceleration takes plenty of time.
The big windscreen was said to improve the air resistance, so that acceleration at higher speed would be better.
However this thread also mentioned, that the ram air effect to the air intake would be significantly less when having the big windscreen, which would result in a lack of power at higher speed compared to Atoms with gunsights only.
Whatever may be right or wrong...
From my experience also having the wonderful big windscreen any acceleration beyond 200kph feels a bit time consuming. However this acceleration still is hardly comparable to other cars and my Atom runs 250 quite easily. Admittedly this is according the Spa speedometer and not GPS, but the Atom still accelerates at those speedo 250 and I always had the impression, that I could even hit the limiter in 6th gear.
The 6th gear btw. is no overdrive in the civic, where you hit the limiter at 220kmp (speedo) in 5th gear.
As my basecap does not at all fly away at 250 and because the air appears to nicely be lead over the car I would expect, that an Atom with big windscreen might be slightly faster.
Probably the acceleration at lower speeds is worse because of the higher weight
If your Atom already had problems as n/a I remember a civic, that was not able to exceed 220kph acc. speedo, while all others ran about 245-250 in original spec. This also did not improve by even adding bold-ons like catback and race catalyst. The result on a dyno was about 180bhp(-).
The funny thing about it was, that without changing any hardware between this dyno run and the following ECU adjustment the last dyno after ECU was finally adjusted, showed 220+bhp. So probably a more serious issue with the ECU at that Civic.
As long as you do not have figures to compare the acceleration of your 3-310 and your 2-275 it is perhaps also the missing wind and noise impact, "making" the new one "slower".
I have always remembered, that the passenger drive in your 275 was a lot more spectacular than in my later 300. The driver may had made the difference but I guess you will experience something similar, when you compare driving with and without windscreen.
Re: Topspeed with windscreen lower???
Have you already had the chance to check this?speedmachine wrote: ↑Thu Jul 05, 2018 10:28 am I’m gonna try and see what km is top speed with and without windscreen, going to Germany end of juli and I will start out with windscreen.
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Re: Topspeed with windscreen lower???
Nope, next week is planned to test back 2 back
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Re: Topspeed with windscreen lower???
Well, topspeed wasn’t limited due to the windscreen, without the problem was the same. I did a lot of thinking and looking at my car and found my problem....the bump stop underneath my acceleration pedal was too high...I simply wasn’t able to give it full throttle. Now it goes about 240, but that was at 34 degrees ambient.
I noticed this car felt slower than my previous 275, but blaimed the window, well now it’s not slow anymore . Finally I have to start shifting at the first shiftlight again to avoid hitting the limiter, I missed the beast.
Did a little acceleration testing with an OBD tool (which is awesome by the way, I can read everything in the car and make perfect diagnosis.) and got from 0-100km/u in 2.709 (best time, average was 2.9), so it works allright. 80-120 in 1.48 sec is prettt awesome too.
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I noticed this car felt slower than my previous 275, but blaimed the window, well now it’s not slow anymore . Finally I have to start shifting at the first shiftlight again to avoid hitting the limiter, I missed the beast.
Did a little acceleration testing with an OBD tool (which is awesome by the way, I can read everything in the car and make perfect diagnosis.) and got from 0-100km/u in 2.709 (best time, average was 2.9), so it works allright. 80-120 in 1.48 sec is prettt awesome too.
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Re: Topspeed with windscreen lower???
I have the big windscreen, and tested my Vmax the other day... easily hit an indicated 160mph.
Just ordered side panels, as I reckon this will make a big difference as well...
Just ordered side panels, as I reckon this will make a big difference as well...
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Re: Topspeed with windscreen lower???
Analogue.... it was still pulling as well.... but I had to back off.... it would have gone well past the 160 mark.
So, taking into consideration overeading %, maybe a true 152mph. But as I said, it was still pulling.
So, taking into consideration overeading %, maybe a true 152mph. But as I said, it was still pulling.
Re: Topspeed with windscreen lower???
....the bump stop underneath my acceleration pedal was too high...[/quote]
How did you determin that it was not WOT? Did you measure it, or trial and error?
How did you determin that it was not WOT? Did you measure it, or trial and error?
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Re: Topspeed with windscreen lower???
How did you determin that it was not WOT? Did you measure it, or trial and error?
[/quote]
I missed a cm of travel, so pretty obvious, but further just tried it, I noticed a big difference in acceleration immediately. I knew from my slower 275 that the limiter gets used a lot and this 3.5 didn’t hit it...ever
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Re: Topspeed with windscreen lower???
But if someone knows a way to actually be 100% sure if you get wot, I would like to know, because obd never says 100% on any car, so reading obd doesn’t actually help
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