Discussion
I noticed on an old posting by Fastbuck that he had checked the BHP of his 300 and foud it to be only 256 BHP.This was in his case due to the boost pressure from the supercharger being about half of what it should have been.
Has anyone else taken the trouble to check their BHP on a dyno or rolling road? Did it match the quoted figures?
I assume that the quoted Atom BHP's are measured at the crank and not at the wheels.
D.
Has anyone else taken the trouble to check their BHP on a dyno or rolling road? Did it match the quoted figures?
I assume that the quoted Atom BHP's are measured at the crank and not at the wheels.
D.
"Fatsbuck" im just big boned.
Anyway ,the supercharger as standard runs at 5 psi(all Atom 300's will run at this power).
Ariel THOUGHT they were running at 9 psi, but there not.
I've had 3 seperate rolling dyno tests and they all came out at around 260 bhp which is right if your charger is running at 5 psi.
If my charger was running at 9 psi i would have 300bhp.
Anyway, i've added 20 bhp so in Ariels eyes i've got a 320 but in my honest opinion ive got a 280bhp Atom.
Still the fastest Atom in the world i think!
p.s i'm have an intercooler made as we speak that will add on another 30bhp. 700bhp per ton, that fast enough for you.
Anyway ,the supercharger as standard runs at 5 psi(all Atom 300's will run at this power).
Ariel THOUGHT they were running at 9 psi, but there not.
I've had 3 seperate rolling dyno tests and they all came out at around 260 bhp which is right if your charger is running at 5 psi.
If my charger was running at 9 psi i would have 300bhp.
Anyway, i've added 20 bhp so in Ariels eyes i've got a 320 but in my honest opinion ive got a 280bhp Atom.
Still the fastest Atom in the world i think!
p.s i'm have an intercooler made as we speak that will add on another 30bhp. 700bhp per ton, that fast enough for you.
Fast buck
Are your BHP on the wheels or somewhere else ?
If it's on the wheels you can add 10 to 11% to have the engine power, so 260 + 10% = 286 BHP, not far from the 300 announced by Ariel.
Ariel wrote me that they are between 5 and 6 psi with 550 injectors on the supercharged Atom, is it your configuration ?
I have asked ariel for an intercooler on my future Atom 300, not really to win HP, but to win on liability on hot summer trackday ! They have asked Jackson Racing for that.
JP
Are your BHP on the wheels or somewhere else ?
If it's on the wheels you can add 10 to 11% to have the engine power, so 260 + 10% = 286 BHP, not far from the 300 announced by Ariel.
Ariel wrote me that they are between 5 and 6 psi with 550 injectors on the supercharged Atom, is it your configuration ?
I have asked ariel for an intercooler on my future Atom 300, not really to win HP, but to win on liability on hot summer trackday ! They have asked Jackson Racing for that.
JP
fast buck said:So is the supercharger only adding 15bhp over the Atom 245? The most expensive 15bhp ever?
I've had 3 seperate rolling dyno tests and they all came out at around 260 bhp which is right if your charger is running at 5 psi.
>> Edited by atom120 on Saturday 30th July 18:12
so you are speaking of BHP on wheels, not on clutch.
When a manufacturer annouces power, it's always on clutch.
My first Atom 220 was dyno-tested between 197 and 200 BHP on wheels and the transmission "loose" was exactly 10%, so about 220 on clutch. I'm not sure that the Hondata really gives 25 HP more after having driving one, but the engine is more drivable and smooth with less exhaust pollution, so agood choice ...
Conclusion : with 5 psi and 550 injectors, the supercharger gives about 5O-60 HP more.
JP
When a manufacturer annouces power, it's always on clutch.
My first Atom 220 was dyno-tested between 197 and 200 BHP on wheels and the transmission "loose" was exactly 10%, so about 220 on clutch. I'm not sure that the Hondata really gives 25 HP more after having driving one, but the engine is more drivable and smooth with less exhaust pollution, so agood choice ...
Conclusion : with 5 psi and 550 injectors, the supercharger gives about 5O-60 HP more.
JP
monza; power tests taken from the crank.
Honda civic type r jap spec engine= approx 210bhp
Hondata ecu= approx 20bhp
Jackson supercharger at 5 psi= Approx 30bhp
All dyno tests are different, some are kind to the customer and some are true.
It all depends on your re mapping and how fast your base engine is in the first place, but put it this way, i know a supercharged atom running at 5 psi will not produce 300bhp.
Unless something is wrong with my car(ive been told it's fine)there have been exagerations on the power outputs with supercharged Atoms.
Honda civic type r jap spec engine= approx 210bhp
Hondata ecu= approx 20bhp
Jackson supercharger at 5 psi= Approx 30bhp
All dyno tests are different, some are kind to the customer and some are true.
It all depends on your re mapping and how fast your base engine is in the first place, but put it this way, i know a supercharged atom running at 5 psi will not produce 300bhp.
Unless something is wrong with my car(ive been told it's fine)there have been exagerations on the power outputs with supercharged Atoms.
Crank : i don't know what it is, if it's after the gear-box and LSD, it's similar result to wheels.
If it's before, i would like to know how it is possible to make the test without putting out the gearbox ???
If "crank" is like "cardan" in french, the result will be more accurate than on wheels, but very similar.
JP
If it's before, i would like to know how it is possible to make the test without putting out the gearbox ???
If "crank" is like "cardan" in french, the result will be more accurate than on wheels, but very similar.
JP
Possibly these 300 BHP are American prototype racing ponies invented by Joe McCarthy.
Search in SELOC, the lotus enthusiasts' forum and in Elise Talk Forums and also read Corky Bell`s books about Turbo- and Supercharging.
BTW: Thank you Dave for starting this thread. That`s mainly why I was still looking from time to time into this forum.
And be care full with your money however you make it .
Hartmut
Search in SELOC, the lotus enthusiasts' forum and in Elise Talk Forums and also read Corky Bell`s books about Turbo- and Supercharging.
BTW: Thank you Dave for starting this thread. That`s mainly why I was still looking from time to time into this forum.
And be care full with your money however you make it .
Hartmut
It seems like I have opened a can of worms here.
Atom do quote 300 bhp for the 300 model and in fairness that is what the engine should produce.
From the responses on the forum one could suppose that this may well not be the case and also calls into question the true bhp output of the other engine options.
Bruce usually knows the answer to all things Atom but it would certainly seem sensible to ask Ariel for some accurate information.
I was seriously considering ordering a 300 but will certainly not spend the extra money if it does not do what it says on the tin. I would appear that Fast Buck is having to invest a lot of time and money to get where he should have been in the first place.
If the supercharger is only running at 5 psi, which is a very low boost pressure, it is hardly worth having. Any form of forced induction creates higher engine temps and must therfore be accompanied by additional cooling measures. This may be difficult to achieve given the Atom's design and weight constraints.
In any event, I would like to know the correct engine outputs before ordering.Most manufacturers quote bhp and torque figures at the crank. This involves attaching the drive shaft of the engine to a dyno. This can not realistically be done when the engine is mounted in the vehicle. Rolling road sofware will measure the output at the driving wheels and then extrapolate the crank BHP. There are a lot of rolling road test centres around the country and they usually charge about £60 to run a test for you. Why not get your Atoms tested?
D.
Atom do quote 300 bhp for the 300 model and in fairness that is what the engine should produce.
From the responses on the forum one could suppose that this may well not be the case and also calls into question the true bhp output of the other engine options.
Bruce usually knows the answer to all things Atom but it would certainly seem sensible to ask Ariel for some accurate information.
I was seriously considering ordering a 300 but will certainly not spend the extra money if it does not do what it says on the tin. I would appear that Fast Buck is having to invest a lot of time and money to get where he should have been in the first place.
If the supercharger is only running at 5 psi, which is a very low boost pressure, it is hardly worth having. Any form of forced induction creates higher engine temps and must therfore be accompanied by additional cooling measures. This may be difficult to achieve given the Atom's design and weight constraints.
In any event, I would like to know the correct engine outputs before ordering.Most manufacturers quote bhp and torque figures at the crank. This involves attaching the drive shaft of the engine to a dyno. This can not realistically be done when the engine is mounted in the vehicle. Rolling road sofware will measure the output at the driving wheels and then extrapolate the crank BHP. There are a lot of rolling road test centres around the country and they usually charge about £60 to run a test for you. Why not get your Atoms tested?
D.
"It would appear that Fast Buck is having to invest a lot of time and money to get where he should have been in the first place."
If I had a true 300hp and i must add a true 500 kilo car i would be a happy man.
I have spoke to Ariel about this and there answer was that all rolling roads differ, ....... but 3 seperate ones being the same!!! make your own mind up.
At the end of the day I love the car to bits and wouldn't give it back, it's the fastest one they do, so that is that.
Mine was weighed at 600 kilos, very little fuel.
Even if i took my back wing off and changed my wheels to Mags it wouldn't be 500 kilos and i've got carbon fibre panels!
But i presume all scales are different too and i did only weight it once.
217.5 hp at the wheels and 600 kilos is not what it says on the tin! but love it anyway.
As you can see this has taken some of my time up so, if anyone has a 300 or 275 out there a dyno test would be interesting as i've just spent 40k on a car which is not 600bhp per ton. views greatly accepted.
>> Edited by fast buck on Sunday 31st July 09:14
If I had a true 300hp and i must add a true 500 kilo car i would be a happy man.
I have spoke to Ariel about this and there answer was that all rolling roads differ, ....... but 3 seperate ones being the same!!! make your own mind up.
At the end of the day I love the car to bits and wouldn't give it back, it's the fastest one they do, so that is that.
Mine was weighed at 600 kilos, very little fuel.
Even if i took my back wing off and changed my wheels to Mags it wouldn't be 500 kilos and i've got carbon fibre panels!
But i presume all scales are different too and i did only weight it once.
217.5 hp at the wheels and 600 kilos is not what it says on the tin! but love it anyway.
As you can see this has taken some of my time up so, if anyone has a 300 or 275 out there a dyno test would be interesting as i've just spent 40k on a car which is not 600bhp per ton. views greatly accepted.
>> Edited by fast buck on Sunday 31st July 09:14
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