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| BEAMS Owners Group Discussion forum for the Beams Owners Group |
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#41 (permalink) | |
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Beams Owners Group
Join Date: May 2007
Location: Inverness, Scotland
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WFX, what was your AFR reading? Mine fell off the bottom of the scale below 10:1 with the stock air box but the induction kit leaned it right out.
Roman, I agree with what you're saying majority of the time but I'm stepping back as I have to admit I don't know enough about dynos to argue. I know I just have to use what's available. My comment still stands -at the moment I'm not too worried about driveline losses and happier to accept some higher error in figures for the method available. I still think that Quote:
..that's my rant over. |
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#42 (permalink) |
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Beams OCD Support Group
Join Date: Feb 2006
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Okay well regardless of our disagreement, :P
I've updated the first page with the new entries, and I've listed your 'wheel horsepower' figures, for the sake of conforming with everyone elses figures. Last edited by Roman; 11-06-2007 at 08:42 PM.. |
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#43 (permalink) |
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Beams Owners Group
Join Date: May 2007
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To be honest Roman, I hadn't realised I was the only one who put it at the fly. You can see the wheel Hp from the chart that I posted so use that if you'd prefer. I think I disagreed more with the comment than the wheel vs. fly argument.
RE: the rpm comment. I didn't pay much notice to it but assumed it was due to the gearbox ratio (presume they used 4th). The difference is 1.06 which was close enough I figured to the 1.03 figure on the red-top web page. Cheers, Richard |
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#44 (permalink) |
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Beams Owners Group
Join Date: Oct 2006
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#45 (permalink) | ||
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Beams OCD Support Group
Join Date: Feb 2006
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Quote:
![]() Quote:
With rolling road dynos, you dont even need to know the engine RPM, wheel speed, gearbox ratios, etc etc... It does the horsepower calculation based on how much torque is applied to the rollers, and the RPM of the rollers. If they're adding on a percentage of power to give your flywheel power figures, then max hp should still occur at exactly the same RPM.... If they're adding 'coast down' losses onto the power that you made at the wheels, well, that's just wrong for all sorts of reasons.... It's adding the engine braking effect as a drivetrain loss for starters. |
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#46 (permalink) |
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Beams Owners Group
Join Date: Oct 2006
Location: Scotland
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heres a link to the type of dyno me and RST used - it's a rolling road but dastek make all sort of wonderful claims about it, have a read and us me what you think.
Dastek Dynamometers | Leading the Dynamometer revolution Theres a brand new dyno dynamics RR just been installed across the road from me - I'm gonna get a power run over their just for comparison. |
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#47 (permalink) |
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Beams Owners Group
Join Date: May 2007
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********edited (bad day at work that day), debate continued later on********
Last edited by RST; 11-22-2007 at 04:08 PM.. |
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#48 (permalink) |
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Beams OCD Support Group
Join Date: Feb 2006
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I'm saying that measuring flywheel horsepower is nonsense, and have been giving valid reasons as to why I think this is the case.
I've yet to read a satisfactory explanation as to how measuring flywheel HP is possible to do with any degree of accuracy, or how it's at all relevant to your cars performance (which is the point of going to the dyno, is it not?) This is a discussion board afterall, for sharing knowledge. If measuring flywheel horsepower is a fallacy in some ways, isnt that something that you'd like to know? It's mostly bandied about because people who dont know much about cars cant understand why their car is making (for example) 200hp (at the wheels) instead of the 250 (at the engine) that it's supposed to (and does!) make. But adding on a random % to appease the unwashed masses shouldnt sit well with anyone interested in having relevant, and comparable results. (which is the point of this post, to ascertain which modifications give benefits, etc) As a good example, check out the post just put in by nikki1887. In the first run, it says 161hp ATW, and 197hp @ engine. In the second run, it says 163hp ATW, and 196hp @ engine. How is it that despite the fact that he's making MORE power at the wheels in the second run, it shows him making less if you only went by the 'at the engine' figures? If (like some dynos do) they only showed the 'at the engine' figures, he'd probably think "Aaah rats, I just lost 1hp, I'll change back to what I had in the first run" When in reality, he'd hav gained approx 3hp from doing whatever he did. If that doesnt tell you that 'at the engine' is a load of useless nonsense, then there's no convincing you. Last edited by Roman; 11-08-2007 at 09:59 PM.. |
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#49 (permalink) |
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Beams Owners Group
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Ill step back into this and I'll edit my previous post -that doesn't help anyone.
I feel like I've been mis-quoted somewhere which is why I was getting hacked-off as I don't think we're debating the same thing. I'm still of the oppinion that your original statement is invalid. However, probably the same as for me saying I don't care about wheel Hp -which admittedley isn't true at all and rightly for the reasons you posted. Somewhere down the line I think I've been picked up as saying that measuring an engine BHP is as simple as measuring a wheel BHP and adding a corresponding fudge figure. In fact, I thought I'd already agreed that it's less accurate. I quoted something off the web page but I must admit, I never realised that test would be in-gear as to be honest I don't think for a minute that's valid either (look I'm agreeing again) and I'm not sure why anyone would think engine breaking came into it, coast down to me means powerless so I assumed they bunged it neutral. I know doing this in neutral would again remove parts from the drive line but I never introduced engine breaking into that discussion. Now reading what they said is reasonably correct, but I would worry why they never spotted this kind of stuff beforehand or during the test itself ...or more importantly the owner. You and I can tell if you've got a partially seized caliper but not half the folk I know. Again, I thought I'd mentioned innacuracies rather than absolute values. Hmm, coast down losses vs acceleration. Jury's out on that one, the two are linked in an ideal world but I agree I'm not sure what the relationship would be. A coast down loss (out of gear of course) will be there under acceleration but totally distorted I guess asd there are different loads applied to bearings etc. I have to say, that I can't see photobucket stuff so Nik's last dyno sheet is summed up by yourself. There are 2 questions I'd ask: How accurate are dynos of any kind -and this is a separate issue? Assuming RWHP only, personally on a 200'ish BHP engine, on 2 dyno runs I personally wouldn't be surprised to see between 3 and 5Bhp difference. That works out something like 1.5-2.5% difference. I'm pretty sceptical on the actual accuracy of measurements generally from the engineering work I've done so far. I'm really nervous about accepting figures of this sort as I'm sure it's clear that repeatability and accuracy are 2 different things. When I saw Nik's dyno sheet the other month we compared and I believe the comment was passed regarding mods and Bhp increases that he had spent >>>> more money and got a return in the order of something that I'd have written off as a measuring accuacy (sorry Nik). When I do this sort of "calibration" through work I'd immediately scrutinise a) the period when the equipment was last calibrated and b) the calibration method. I'm still amazed how folk continue to issue accuracies on their equipment geater than the calibration method in the first place!!!! My second question relates to the dyno centre, not the dyno. or the method. I wasn't impressed with that centre and as far as I can establish the majority of folk I've spoken to who have used them aren't either. I won't get into why as it's too easy to publically flame someone then get a legal letter through the door. I fully agree with you regarding Nik's figures and adds to my suspicions. There are of course folk who are perfectly happy. Nuff said. |
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#50 (permalink) |
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Beams Owners Group
Join Date: May 2007
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God darn my 2 fingered typing and random thumbs hitting my mouse touch pad thingy, I hit post rather than preview. I hadn't finished, reviewed and read it through properly yet. Too late now I guess...... (can one actually kick oneself in the arse or will I just resort to head butting my laptop).
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#51 (permalink) |
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Beams Owners Group
Join Date: May 2007
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......just realised nobody's allowed to form a que for the former arse kicking option. LoL.
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#52 (permalink) |
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Beams OCD Support Group
Join Date: Feb 2006
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you know that you can edit your post after you post it, right?
My original posts are about version 0.7 at best, usually takes an edit or two until they make any sense. ![]() |
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#53 (permalink) |
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Beams OCD Support Group
Join Date: Feb 2006
Location: Auckland, NZ
Posts: 946
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Thanked 56 Times in 36 Posts
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RST....
Please read this. Scroll down to the part where it says "ROLLING ROAD DYNANOMETERS" and read from there on. Puma Race Engines Technical Guide - Measuring Engine power - engine dynos and rolling road dynos And then, read this. Puma Race Engines Technical Guide - Coastdown Losses as measured on Rolling Road dynos |
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| The Following User Says Thank You to Roman For This Useful Post: | mr2ya (04-06-2008) |
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#54 (permalink) |
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Beams Owners Group
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Car owner: 2old2rusty
Car type: Corona ST150 engine type:Red Top BEAMS max HP @ RPM: 174.19 PS (WHP) max torque @ RPM: 17.98 Kg-M relevant mods: K&N air filter & e-manage (blue), Denso Iridium IK20 spark plugs, exhaust piping 2.25", de-cat straight flow muffler, everything else is stock. ![]() Last edited by 2old2rusty; 04-06-2008 at 02:21 AM.. Reason: typo |
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#55 (permalink) |
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Beams Owners Group
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Update.
Car owner: 2old2rusty Car type: Corona ST150 engine type:Red Top BEAMS (with ST183 gear box) max HP @ RPM: 177.53 PS (WHP) max torque @ RPM: 18.28 Kg-M relevant mods: K&N air filter & e-manage (blue), NGK Iridium spark plugs, exhaust piping 2.25", de-cat straight flow muffler, SARD fuel regulator & oversized throttle body . The rest remained unchanged.Next step: exhaust piping to be increased to 2.5". ![]() Last edited by 2old2rusty; 04-06-2008 at 02:20 AM.. Reason: typo |
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#56 (permalink) | |
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Banned
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Quote:
i didnt want to have to explain it, some of these knuckle heads would have surely argued. THANKS! |
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#57 (permalink) |
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Beams Owners Group
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Update.
Car owner: 2old2rusty Car type: Corona ST150 engine type:Red Top BEAMS (with ST183 gear box) max HP @ RPM: 184.41 PS (WHP) max torque @ RPM: 18.72 Kg-M relevant mods: K&N air filter & e-manage (blue), NGK Iridium spark plugs, de-cat straight flow muffler, SARD fuel regulator & oversized throttle body. Exhaust piping increased to 2.5". ![]() ![]() Last edited by 2old2rusty; 05-13-2008 at 11:12 PM.. Reason: typo |
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#58 (permalink) |
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Beams Owners Group
Join Date: Mar 2005
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so you went from 177 to 184 rwhp by simply changing the exhaust piping diameter from 2.25 to 2.5?
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#59 (permalink) | |
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Beams Owners Group
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Quote:
![]() Last edited by 2old2rusty; 05-13-2008 at 11:11 PM.. Reason: typo |
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#60 (permalink) |
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Beams Owners Group
Join Date: Mar 2005
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Thats impressive
I think you might start a trend with that information ![]() |
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