quicksilver Posted May 31, 2009 Share Posted May 31, 2009 Took my 2005 350z roadster to a rolling road day on saturday and the car only produced 256BHP to the flywheel. It only has a JWT pop charger but aren't they supposed to be 276bhp standard? It's just had a full fluid service and has no running issues, I'm gutted to say the least. Has anyone else had this experience?? I have heard that the cars cats have to be fully heated to make top power and this is the only thing I can think of why the car didn't reach around the 276bhp mark?? Quote Link to comment Share on other sites More sharing options...
clarkie34 Posted May 31, 2009 Share Posted May 31, 2009 My 06 296bhp only made 280 at the fly last week.Cone filters lose you power as they get hot. Quote Link to comment Share on other sites More sharing options...
quicksilver Posted May 31, 2009 Author Share Posted May 31, 2009 My 06 296bhp only made 280 at the fly last week.Cone filters lose you power as they get hot. surely a cone filter can't lose you 20bhp. My celica gt4 with just an induction kit ran 255bhp, which is spot on standard power. I'm tempted to go back with the standard filter and see what happens. Quote Link to comment Share on other sites More sharing options...
Richie Posted May 31, 2009 Share Posted May 31, 2009 Mine put out 314.5 at the fly a few weeks ago when I had it on there, completely stock. The guy who owns the rolling road said that cars that had been tested elsewhere (in the local-ish area) got lower results on this one, than others so they claim it not to overstate the measurements but well its more about how it feels than what it can measure on the rollers. Quote Link to comment Share on other sites More sharing options...
maz77 Posted May 31, 2009 Share Posted May 31, 2009 Took my 2005 350z roadster to a rolling road day on saturday and the car only produced 256BHP to the flywheel. It only has a JWT pop charger but aren't they supposed to be 276bhp standard?It's just had a full fluid service and has no running issues, I'm gutted to say the least. Has anyone else had this experience?? I have heard that the cars cats have to be fully heated to make top power and this is the only thing I can think of why the car didn't reach around the 276bhp mark?? dont think thats a very accurate measurement method for BHP at the fly wheel unless you taken your engine out. might be worth doing an oil change and spark plugs if they are old and going back to stock air intake. I personally think WHP is what matters mate Quote Link to comment Share on other sites More sharing options...
Pimm Posted May 31, 2009 Share Posted May 31, 2009 I would not worry about what figures you acheived on the rollers. You could always take the popcharger off and take it back and see what difference it makes but imo there are so many factors involved in using these(rollers i mean). Take your figures with a pinch of salt unless you go out and spend huge amounts on your engine and then worry that it is below oem. Quote Link to comment Share on other sites More sharing options...
H5 Posted June 1, 2009 Share Posted June 1, 2009 How hot was it? How big were the fans blowing air into the car? SO many variables...... Quote Link to comment Share on other sites More sharing options...
Chris`I Posted June 1, 2009 Share Posted June 1, 2009 Most importantly what were your figures at the wheels? You'll be amazed at how much heat soak can destroy BHP. Not an exact measurement, but Ben and I took his Evo and my Zed out with a PerformanceBox, and with my intake temps well up there I got less than 230WHP, but when we managed to drive it around and cool it down, we got 240WHP which is what it was dyno'd at last time. Not by any means accurate, but gives you an estimate of what heat soak can do. Popchargers kill your power from a standing start but once moving they are not differnt to the standard intake from what I've seen. Quote Link to comment Share on other sites More sharing options...
Rob_Quads Posted June 1, 2009 Share Posted June 1, 2009 My few thoughts a) Ignore power at the fly and look at power at the wheels - there are just too many variants to reliably work out power at the fly (without removing the engine) What was the ambient temp as the higher it is the lower it will be (and a 25 degree summer to a 5 degree winter will make quite a difference c) Cone filters may well 'appear' to loose power on a rolling road but these are NOT driving environments they are normall either sealed or enclosed rooms which have very poor circulation (putting a big fan in front of the car does not count as good circulation In Summary - i would not worry about it to be honest. if its just been serviced and it drives well thats the main thing Quote Link to comment Share on other sites More sharing options...
Gaz Walker Posted June 1, 2009 Share Posted June 1, 2009 My few thoughts a) Ignore power at the fly and look at power at the wheels - there are just too many variants to reliably work out power at the fly (without removing the engine) What was the ambient temp as the higher it is the lower it will be (and a 25 degree summer to a 5 degree winter will make quite a difference c) Cone filters may well 'appear' to loose power on a rolling road but these are NOT driving environments they are normall either sealed or enclosed rooms which have very poor circulation (putting a big fan in front of the car does not count as good circulation In Summary - i would not worry about it to be honest. if its just been serviced and it drives well thats the main thing Couldn't put it better myself Quote Link to comment Share on other sites More sharing options...
3FIDDYZ Posted June 1, 2009 Share Posted June 1, 2009 Mine put out 314.5 at the fly a few weeks ago when I had it on there, completely stock. The guy who owns the rolling road said that cars that had been tested elsewhere (in the local-ish area) got lower results on this one, than others so they claim it not to overstate the measurements but well its more about how it feels than what it can measure on the rollers. What year car ? Quote Link to comment Share on other sites More sharing options...
Stew Posted June 1, 2009 Share Posted June 1, 2009 Dyno numbers are for pubs..... On the road is what counts. Quote Link to comment Share on other sites More sharing options...
neodc Posted June 1, 2009 Share Posted June 1, 2009 I got mine dynoed a while ago and i was disapointed, the guys at mine did make a few mistakes and that may be why mines low, but i'll be going to Corntey miller in a few weeks to get mine done again. dave Quote Link to comment Share on other sites More sharing options...
quicksilver Posted June 1, 2009 Author Share Posted June 1, 2009 dont think thats a very accurate measurement method for BHP at the fly wheel unless you taken your engine out. might be worth doing an oil change and spark plugs if they are old and going back to stock air intake. I personally think WHP is what matters mate How often should the plugs be changed? the cars just done 60,000 and probably has the original ones in Quote Link to comment Share on other sites More sharing options...
Stew Posted June 1, 2009 Share Posted June 1, 2009 dont think thats a very accurate measurement method for BHP at the fly wheel unless you taken your engine out. might be worth doing an oil change and spark plugs if they are old and going back to stock air intake. I personally think WHP is what matters mate How often should the plugs be changed? the cars just done 60,000 and probably has the original ones in Think it's 54k or 5 years.... I might be wrong though! Quote Link to comment Share on other sites More sharing options...
H5 Posted June 2, 2009 Share Posted June 2, 2009 I think Stew is right on the plug change timies...... Quote Link to comment Share on other sites More sharing options...
Chris`I Posted June 2, 2009 Share Posted June 2, 2009 I think Stew is right on the plug change timies...... +1 - Mine got done at 54k and the mechanics said they were well past their best. Phil told me its better to do them at about 40k miles or even less (I think he did them every 30k). If you know a good garage they can do it without removing the plenum as Nissan tell you to, so its not a big job or if you are handy, can do them yourself Quote Link to comment Share on other sites More sharing options...
200sx Posted June 2, 2009 Share Posted June 2, 2009 Abit of a thread hijack, but doesn't the service manual say the plugs should be changed every 100,000 miles. I don't think there is any mention of having to remove the plemum. I might whip the engine cover off and have a look tonight, at 50,000 miles they may be getting a little old by now. Quote Link to comment Share on other sites More sharing options...
Chris`I Posted June 2, 2009 Share Posted June 2, 2009 Abit of a thread hijack, but doesn't the service manual say the plugs should be changed every 100,000 miles. I don't think there is any mention of having to remove the plemum.I might whip the engine cover off and have a look tonight, at 50,000 miles they may be getting a little old by now. One Nissan garage certainly told me you had to. But you are correct the manual just says to remove the engine cover. In my service book it say 54k service to change plugs Quote Link to comment Share on other sites More sharing options...
Richie Posted June 2, 2009 Share Posted June 2, 2009 Mine put out 314.5 at the fly a few weeks ago when I had it on there, completely stock. The guy who owns the rolling road said that cars that had been tested elsewhere (in the local-ish area) got lower results on this one, than others so they claim it not to overstate the measurements but well its more about how it feels than what it can measure on the rollers. What year car ? its a 58, so should have 309 hp anyways. The WHP figure is pretty poor at only 233, so maybe its crap at calculating transmission losses. Quote Link to comment Share on other sites More sharing options...
quicksilver Posted June 2, 2009 Author Share Posted June 2, 2009 Looks like a new set of plugs would be a good start, any reccomendations for the plugs NGK Iridiums?? Don't suppose there's a how to on here somewhere? Quote Link to comment Share on other sites More sharing options...
sunset350z Posted June 2, 2009 Share Posted June 2, 2009 You can pick up the ngk iridiums for about 50ish bucks. There is a 'how to' on here somewhere but it is straight forward really. Quote Link to comment Share on other sites More sharing options...
matth76 Posted June 3, 2009 Share Posted June 3, 2009 What wheel horse power figure did you get? The wheel horse power is what matters because all dynos measure the power/torque at the wheels. Flywheel horsepower is always "estimated" and different garages use different estimations of what your transmission losses are in order to estimate (and they are only estimates) the flywheel power - which is what all manufacturers advertise and people brag about. However wheel horsepower is the best comparisson as it is accurate. The transmission losses in the 350z are about 15-17%, which means to get 276bhp you need ~232 wheel horsepower. Having said that even wheel horse power can vary a lot from roller to roller. I have had my car on two different rollers and the difference was as much as 20 wheel horse power! However I suspect there was a calibration error of some kind as I took it to a well established Nissan specialist: GT Art and it made a more realistic 233 wheel horse power and over 244 wheel lbs/ft, equating to ~280bhp (meaning at the fly) and ~290lbs/ft. If you're in the south east try and visit them http://www.gtart.co.uk. You have to remember that power in all cars varies a lot and varies from day to day. Advertised power figures are only a guide. Quote Link to comment Share on other sites More sharing options...
3FIDDYZ Posted June 3, 2009 Share Posted June 3, 2009 What wheel horse power figure did you get? The wheel horse power is what matters because all dynos measure the power/torque at the wheels. Flywheel horsepower is always "estimated" and different garages use different estimations of what your transmission losses are in order to estimate (and they are only estimates) the flywheel power - which is what all manufacturers advertise and people brag about. However wheel horsepower is the best comparisson as it is accurate. The transmission losses in the 350z are about 15-17%, which means to get 276bhp you need ~232 wheel horsepower. Having said that even wheel horse power can vary a lot from roller to roller. I have had my car on two different rollers and the difference was as much as 20 wheel horse power! However I suspect there was a calibration error of some kind as I took it to a well established Nissan specialist: GT Art and it made a more realistic 233 wheel horse power and over 244 wheel lbs/ft, equating to ~280bhp (meaning at the fly) and ~290lbs/ft. If you're in the south east try and visit them http://www.gtart.co.uk. You have to remember that power in all cars varies a lot and varies from day to day. Advertised power figures are only a guide. Agree that numbers are guides but he has a 309 bhp car... that means its lost almost 25% of its power... Dyno or not his numbers are wrong but agree he needs to try a different rollers for a comparison... I would also not let the dyno operator know you have had it done before, just so you get other readings.. Matt, did Gary tune the car for you or havnt you decided yet? Quote Link to comment Share on other sites More sharing options...
quicksilver Posted June 3, 2009 Author Share Posted June 3, 2009 I'm kinda hoping that the figure I got of 256bhp is wheel horespower not flywheel as that would be more realistic from what you guys have said - I'll check when I get my dyno printout soon, as he ran out of ink on the day so he couldn't print it out. Although according to the 15% that would make the car about 290bhp to the flywheel. Quote Link to comment Share on other sites More sharing options...
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