Quote from Thomas H :

You were generalizing a bit there JTbo, that's all. Had to make a comment...

Thomas

Ah surely, but that is probably same that side of sea, because at least those rally cars that are sold here do lose quite lot of power again when brought to your place at least according to dyno tests

Similar to freeflow airfilters, how they make big power increase in NA engines and in fact they loose some power because intake temps rise. Marketing, making stuff sell. Again same with dyno business, they show too much bhp just like Tristan says, sales, profit, that is called business and sometimes it comes to bit ridiculous as these rally cars they try to sell _specially_ from Finland to Sweden or opposite direction, we have this little competitive history, which at least I find very amusing and worth joking

Duh, brain fade moment... obviously, you are correct.

/beats head with frying pan for being a complete dunce

even then i think your being generous, like i said honda/suzuki ect quote 170bhp at the crank for their 1000cc sports bikes but dyno's show alot less

Reading this thread almost made me vomit, and my stomake is quite gutsie...

The pure amount of generalisation, pessimism and cynnicim is alone a big reason to kill this thread but on the other hand the amount of knowledge some people showed in a fashionable and polite way almost slid the scale to 0.

Don't you think it's wrong to go the same way every time someone is trying to make a point but makes the big mistake of taking "his" knowledge and putting it up against figures?
About free-flow air filters never giving more power, rolling roads are crap, dynos don't work, this and that and so on. I don't now what the word is for this type of communicating so unnecessary repeating will do for now.

A properly cordoned off free-flow air filter will give extra power to some cars.
A, according to engine displacement and configuration correct, free-flow exhaust will give extra power to many but not all cars.

Rolling road shows what power you have at the wheels and that is the only, to me, figure that matters, why quote the engine power if the WBHP is 50 BHP lower?

A dyno is to me the type of device you bolt to the wheel hubs whereas a rolling road is no more than 2/4 rolling tubes, correct? And this gives a more correct reading bla bla bla.

And saying that all commercial dynos are over-reading, isn't that a bit of generalization? Since you(tristancliffe) haven't tested all the cars in the world with all the different dynos available(no time in hell), probably not even the most popular in the UK with the standard dynos(possible but come on?) you can't say for sure that it's always in their interest to make them over-read.

Atleast here in Sweden we want the real power, to a point, getting extra big figures at one dyno when the manufacturer of the after-market parts quoted a 5% (example) lower BHP upgrade you know somethings wrong, you don't get positively surprised.

I'm just mad at everyone always giving these statements, hardly arguments, and getting away with it.

Don't bother to correct any misspells unless they alter the meaning of the sentence, it's 4:40 am and I still spell okay compared to some others whom have english as their native language.

Generalisations comes because kids believing F&F crap are generalizing just opposite stuff, so it is constant rope pulling...

Yes, freeflow filters can help in some cases to get bit more power, mostly those are to be avoided because weaker filtering and unless installed so that cooler air is available than most common next to exhaust manifold install offers. Some cars stock filter is just too small to provide enough air to engine, in these cases freeflow filter can help, but better option is to find bigger stock type filter if possible to fit to engine room.
Mostly freeflow filters are something that makes seller happy and kid buying one thinks engine is more powerful because of increased intake noise.

Simple way to test if air filter is resisting element is to measure vacuum between throttle plate and air filter or if you have turbo, then between air filter and turbo intake.

At least here we don't separate dyno or rolling road, everything is talked as dyno, that is because car people is often bit simple (sorry, don't hit too hard ) guys that do stuff quite conservative way so to say. So many don't even know difference, that is then why there is only one word used. But yes, dyno which you bolt to wheel hub is giving more reliable reading of wheel power, as I understand Rototest should be quite reliable also, almost only one we can say it measures power without removing engine from car and not questimates it.

Why to repeate these things then? Well, because there are more of those who don't know than those that do know and hopefully people can gasp little idea of questioning what marketing tells them from these things.

the only things i said is that dyno's can be made to over read by putting the temp sensor in a hot cup of tea, and that manufactuers over quote their own power figures, both of those's statments are true, ive never seen a bike make whats been quoted from the manufacturer standard

Quote from andybarsblade :

the only things i said is that dyno's can be made to over read by putting the temp sensor in a hot cup of tea, and that manufactuers over quote their own power figures, both of those's statments are true, ive never seen a bike make whats been quoted from the manufacturer standard

You do know that as of 2003/2004 alot fewer car companies stopped over-quoting their power figures because of massive lawsuits in the US? Mazda had to pay an enormous sum of money because the RX8 lacked 7-8 bhp.

Practically, there is no way a dyno could tell you what the engine actually makes IRL operation, even when the dyno is fundamentally very accurate and precise. The difference in actual power difference between a car with an open/closed hood running on a dyno and a car running full speed at the track with plenty of cool airflow into the air intake and excellent cooling (aka so good that the fan is actually switched OFF to reduce fan parasitic drag) can be quite surprising, especially in these days of electronically managed engines.

Let's look at this simple scenario. A car is on a high speed track and it's cooling system is more than adequate for keeping temperatures in the optimal ranges. With a well designed and implemented carbon fiber hood that's well vented as well, underhood temps are actually quite low as the high speed intake air easily removes all excess heat. With a cold air intake right at the grille opening, the engine enjoys an excellent supply of cool and clean air. The ECU senses this extra air inflow and deems it safe to advance ignition to maximize power and efficiency. Under these condtitions, the actual power produced in operation is significantly higher than dyno tests could measure (assuming an accurate dyno). If there's a well designed and installed ram air intake, the power output actually increases with speed by as much as 5% or more as speed climbs.

Then there's the situation where a poor car is on a dyno revving its guts out in an attempt to generate a good power curve with stale, non-moving air. Poor thing asphyxiates and burns up and the ECU retards ignition to protect the engine. Result? Lousy power curve.

unless you use an engine dyno

Manufacturers have the option of quoting power figures as SAE standard. When they do this, a neutral SAE official attends and oversees the test to make sure there's no monkey business going on. As a result, the figures manufacturers are quoting ought to be quite accurate, at least as far as what the engine is doing on a test stand.

I've had a lot of people use rolling road dyno data in my drag racing simulation and report back very accurate results, so I'm a little surprised to see that these dyno shops overquote the power so frequently. They'd need to alter the software that comes with the dyno in order to do it, I'd think (maybe there's an ini file or something that allows it).

Still, the reasoning makes sense for overquoting, so perhaps it's not all that surprising or infrequent.

lol tyres arnt everything allso my car with 235's cam get off the line as good as a car with 265's suspension weight distrobutions tq curv's all these things come into factor and i have seen 500 HP cars run 14.5's with 117 mph u can run 13's at 98 mph if u get a good launch