PDA

View Full Version : Low HP and Torque readings



Toeks
07-21-2006, 03:14 PM
I dyno'd my 1995 525 end last year and it came up with the following numbers:

132 HP
143 N.m

Are these numbers acceptable (yes, the car is 11 years old) or not? It runs smooth and there are no problems I'm aware of. Big question; where do I start to "fix" the old beast. What are the major things that cause such a drastic degredation in numbers?
(I have bought an EAT chip but havent dyno'd yet, just want to know what else...)

Espen
07-21-2006, 03:27 PM
rebuild your engine head, change your pistonrings.
do a engine flush, clean out the exhaust pipes. Replace all ignition parts. Do a engine flush and change oil and filter.

Qube
07-21-2006, 03:37 PM
Plus a shogun reset after you do all that :)

Alexlind123
07-21-2006, 06:07 PM
Plus a shogun reset after you do all that :)

Why do you call it a "shogun" reset?

Qube
07-21-2006, 07:15 PM
Because... it's a credit to Shogun! No way... you didn't know that?

http://www.bimmer.info/forum/showthread.php?t=21543&highlight=shogun+reset

http://www.bimmer.info/forum/showthread.php?t=2806&highlight=shogun+reset

632 Regal
07-21-2006, 07:39 PM
we all know that, Alex is on them meds again.
[QUOTE=Qube]Because... it's a credit to Shogun! No way... you didn't know that?

winfred
07-21-2006, 08:49 PM
if the engine has good compression and doesn't use more then a quart or so of oil between changes it's in fine shape, it just comes down to whats out of spec like a worn airflow meter or 02 sensor or old crappy injectors would be the most likely votes, other things like timing chain stretch and vacuum leaks chip away at power too, general rule of thumb is 15-20% of avalable power gets lost in the drive train through friction so that takes it into the 150-160 range from stock in perfect factory fresh condition, from there another 20 odd hp could be easly eaten up by any one or more of the things i listed and others i didn't, dynos can be way off too compared to other units of the same brand/model depending on how it's set up and correction factor. the good thing is now that you have a base line you can go back to that same dyno and with the same correction factor will be able to track improvements

Alexlind123
07-21-2006, 08:50 PM
Because... it's a credit to Shogun! No way... you didn't know that?

http://www.bimmer.info/forum/showthread.php?t=21543&highlight=shogun+reset

http://www.bimmer.info/forum/showthread.php?t=2806&highlight=shogun+reset

On 10-13-2005, shogun posted the following (with irrelevant parts cut out, but none added):


The reset is basically nothing special. Every shop makes it, we make it sometimes without knowing it by disconnecting the battery for car winter storage or a repairs on the car.
All that is a reset.
If you do not notice any change, then there was nothing wrong on the engine management.
Do not expect to have suddenly 300 HP more or things like that ;)
It also will not cure mechanical problems on the car.
It is just like 'cleaning' your PC and make all the programs to original state.

Qube
07-21-2006, 09:41 PM
Shhhhh! Don't discredit the shogun reset! It works a silent miracle... like the button on Lost (http://www.lostpedia.com/wiki/Main_Page)

Alexlind123
07-21-2006, 09:52 PM
Thats like saying the white man invented smallpox when we came to american, when we were just carriers.

Toeks
07-22-2006, 06:22 AM
if the engine has good compression and doesn't use more then a quart or so of oil between changes it's in fine shape, it just comes down to whats out of spec like a worn airflow meter or 02 sensor or old crappy injectors would be the most likely votes, other things like timing chain stretch and vacuum leaks chip away at power too, general rule of thumb is 15-20% of avalable power gets lost in the drive train through friction so that takes it into the 150-160 range from stock in perfect factory fresh condition, from there another 20 odd hp could be easly eaten up by any one or more of the things i listed and others i didn't, dynos can be way off too compared to other units of the same brand/model depending on how it's set up and correction factor. the good thing is now that you have a base line you can go back to that same dyno and with the same correction factor will be able to track improvements

Seriously thanks for the input guys, I now have a clearer path ahead. Its good to have a project again (the goal being getting her back to tip top shape!) How much would I be looking at spending for a rebuild etc.?

Bill R.
07-22-2006, 08:14 AM
hype surrounding dyno numbers and many of them tend to be exaggerated. Dyno calibrations can vary wildly from unit to unit and as to how its calibrated. Here's what your motor produces outside of the car on a dyno stand under the very best of conditions, ie. best temps, sea level , engine just warm enough. Whenever the manufacturer does these dyno test you can rest assured that its under the ideal conditions to produce the max numbers. In the real world under your test conditions things might be very different, you don't state what the ambient was , was the engine temp was, what the altitude was , what the air density was as well as humidity. All of these things make a huge different in dyno numbers. Drivetrain frictional losses are frequently far more than 15 to 16% , more like 30% depending on the age of the vehicle, lubes used in the trans and differential, frictional loss through the tires etc etc... I would be perfectly happy with your numbers if as Winfred said you're not using much oil and the plugs look fine when checked and everything else seems normal such as fuel consumption.









I dyno'd my 1995 525 end last year and it came up with the following numbers:

132 HP
143 N.m

Are these numbers acceptable (yes, the car is 11 years old) or not? It runs smooth and there are no problems I'm aware of. Big question; where do I start to "fix" the old beast. What are the major things that cause such a drastic degredation in numbers?
(I have bought an EAT chip but havent dyno'd yet, just want to know what else...)

Toeks
07-23-2006, 05:13 AM
Exactly why I asked the experts. As I said, the car runs smooth, there are no abnormal sounds from what I can deduce and no problems whatsoever. It has lately been giving me "coolant level" errors though. (not that the coolant is ever low).

infinity5
07-23-2006, 09:51 AM
Exactly why I asked the experts. As I said, the car runs smooth, there are no abnormal sounds from what I can deduce and no problems whatsoever. It has lately been giving me "coolant level" errors though. (not that the coolant is ever low).


Those sensors are notorious for being faulty. I'm planning on just jumping it out or something and not worrying about it.

Toeks
07-23-2006, 10:53 AM
My bravado doesnt go quite that far. (it usually never passes watching Oprah, alone...)

I need to drain the coolant fluid anyway, so I'll make a job of it and remove the radiator etc. Give it all a good once over, perhaps replace the level sensor while I'm at it. If it does solve my problem, I'll let you know...

winfred
07-23-2006, 02:22 PM
don't need to remove the radiator to do the sensor


My bravado doesnt go quite that far. (it usually never passes watching Oprah, alone...)

I need to drain the coolant fluid anyway, so I'll make a job of it and remove the radiator etc. Give it all a good once over, perhaps replace the level sensor while I'm at it. If it does solve my problem, I'll let you know...

Toeks
07-24-2006, 02:13 PM
Actually I want to go through all the piping and check for leaks etc. Since buying the car I havent checked for anything major, so I'm gonna do it! Drove 200km today and it never gave me the coolant level bleep. Perhaps my intent has scared the gremlin away. Mwhaaa.

winfred
07-24-2006, 07:40 PM
may be a bad connection at the sensor, squeeze the female part a little tighter

Toeks
07-25-2006, 01:28 PM
I'll give it a try over the weekend. Will have my uncle's pit available so I'm looking to do a few things to my pride and joy.