Anyone know the rough BHP with the following:

 

Apexi Induction

Mongoose Exhaust

ECU Upgrade

Profec B 2 Spec (1bar)

Lightweight U/D Pulley

Lightened Flywheel

Removed that metal bar in the back hatch....

 

I'm guessing the F/W and pulley don't actually increase BHP?????

I'm guessing the F/W and pulley don't actually increase BHP?????

 

Yes they do - maybe 20 to 40bhp?

Not sure on the total but around 360 to 380 ish?

Anyone know the rough BHP with the following:

 

Apexi Induction

Mongoose Exhaust

ECU Upgrade

Profec B 2 Spec (1bar)

Lightweight U/D Pulley

Lightened Flywheel

Removed that metal bar in the back hatch....

 

I'm guessing the F/W and pulley don't actually increase BHP?????

 

Hi Alex,

 

That is a very difficult question to answer because apart from the listed modifications it also depends on the condition of various engine/transmission components.

 

If you took two completely stock 1991 Z32's (identical mileage, etc) and put them on the rollers you will get two different bhp readings. One may have more loss through the transmission than the other, perhaps the engine internals aren't in as good a nick as they should be. The point is that in stock form your car (or any car) could already be down on the factory quoted bhp figure. If you then bolt on any modifications your expected outcome will probably be less than you expected.

 

I'm sorry if this sounds boring and dull but I get asked this same question every week by clients who buy performance items from me. The short answer is to say that any performance modification will add bhp but it is impossible to state how much bhp is added. In my opinion it is much more relevant to quote a "range" of bhp increases which depend on the condition of the car and its components.

 

All the best mate,

 

Dan

Unfortunately Light weight pulleys and Fly wheels DO NOT add extra power to your engine. They are lighter so they require less "effort" from the engine to turn them. This means your Driveline does not soak up as much power from the engine so you have less transmission loss when calculating your "at the wheels" power. If that makes sense.

If the U/D pulley reduces the revs of ancilliaries by being smaller or larger depending on whether it is driving or driven it will take less power out of the engine to drive it. Resulting in a BHP gain, this is not extra generated power rather it is less used up.

 

Providing your OK with slower alternator or whatever with the resultant gearing shift then your going to GO FASTER ....!!

U/D pulleys are the same size as the stock items?? so gearing dosnt come into it :-)

no dude they are slightly smaller, hence the name, underdrive

lighter weight on the rotating crank assembly DOES free up BHP! it takes a certain amount of power to actually turn the crank. reducing this weight will gain you bhp. forgot what it is but think its around 1 - 1.5bhp/lb

considering the stock crank pulley weighs in at around 11lbs an underdrive pulley weighs in at around 3-4lbs bit of a saving,and should free up the revs,also the fact there slightly smaller and using smaller belts,this is turn means slightly less rotation on the ancilaries,waterpump,power steering etc

 

avoid cheap undedrive pulleys these are not balanced correctly and over years,probably dont do the bearings any good,best on the market is the unorthodox pulleys these are tested and IMO are the best on the market for the z32

Agree, wouldnt put anything else on a car - especially the ebay ones. UO racing ones may be expensive but theres a reason for that.

 

Yes Paul it does require less effort to turn the crank - but the engine dos'nt produce any more power. Its the engine power that turns the crank in the first place. If you put any engine on an engine Dyno, the only things that effect power are those in the intake/exhaust and combustion process (Crank Horsepower).

 

When measuring Power at the wheels, we have to take into consideration drive train losses. Ie. Flywheel, clutch, gearbox, driveshaft, diff. If we can make these a lighter rotating mass then it is easier for the engine to move them, this means the less of the engine power is soaked up by these items, hence more power available at the wheels.

 

But dont take my word for it, have a look at any Lightened Flywheel manufacturers site for instance and they will say the same..

 

there is also a good insight into the subject here, its the last question, worth a read

http://www.nissanperformancemag.com/march03/ask_sarah/

 

Marty

 

Its the engine power that turns the crank in the first place.

 

 

exactly!! do you think it takes the same amount of power to turn the crank regardless of how much it weighs??? what if it weighed 1/2 ton. how much power do you think we would measure on a dyno??

 

you are freeing up power that would be used to actually turn the additional weight! the more weight on the crank assembly, the more power you need to turn it. assuming were not running an engine in a friction free vacuum!!!

yes that what ive said? your not producing anymore engine power with lightened components - but increased power at the wheels. What im saying is lightened components dont actually add Power to your engine just less loss in the drive train. Where as a bigger turbo would add extra power to the engine. I havnt actually said anything wrong in my posts?

ok, maybe were at cross terms here, you seem to have said in your post that the engine does not produce more power if you lighten the crank assembly.

 

what i am saying is that it will!

 

there will be a greater measurable amount of power at the F/W if you reduce the weight of rotational components in an engine as there are less frictional losses because of the weight reduction.

 

:)

Anyone know the rough BHP with the following:

 

Apexi Induction

Mongoose Exhaust

ECU Upgrade

Profec B 2 Spec (1bar)

Lightweight U/D Pulley

Lightened Flywheel

Removed that metal bar in the back hatch....

 

I'm guessing the F/W and pulley don't actually increase BHP?????

 

I've pretty much got exactly the same mods and i am doing a dyno run tomorrow so i will let you know the outcome.

ok, maybe were at cross terms here, you seem to have said in your post that the engine does not produce more power if you lighten the crank assembly.

 

what i am saying is that it will!

 

there will be a greater measurable amount of power at the F/W if you reduce the weight of rotational components in an engine as there are less frictional losses because of the weight reduction.

 

:)

 

Yup, but he dosnt have a lightened Crankshaft - he has a lightened flywheel - (me thinks this is were we have went off to tangent town :p . )which just takes less power to turn it as its rotational mass is smaller. This gain will only be seen through less drivetrain losses when measured at the wheels. Though it will allow the engine to rev more easily.

 

I know engine power where it counts is measured at the crank. so anything improved after the crank will not effect the power the engine produces. BUT it will allow more of that crank HP to be applied at the wheels (less drivetrain losses). Therefore a lightened Flywheel does not add anymore power to your engine.

 

I think we may have to put this to bed Paul, dont want it turning into a youre right and im wrong or visa versa thread. ;)

The flywheel and pulleys are usually thought of as part of the engine... they go on the big lump under the bonnet ;)

 

Underdrive pulleys are lighter and also "under drive" or turn the anciliaries slower so you aren't wasting as much energy on other things.

If you lighten it like you said you'll have more power!

Not that hard to understand is it? :rofl:

 

I'm sure I said in the first post they will give an increase :mac1: LOL

it will only show an increase at the wheel's the enigine it self will still produce the same bhp at the fly it will just rev quicker there will be no power increase as the enigne is still getting same timing fuel air ect ect

 

yes on a wheel bhp you will see an increase as less power is lost through the drive train however the engine will still produce what ever bhp it was producing before.

:rofl: LOL will someone please lock this thread

:rofl: LOL will someone please lock this thread

 

LMAO :D

 

surely the term "measured at the flywheel" gives a clue!! - unless youve got a starting handle you aint gonna get a figure on an engine dyno at all!! :rofl:

FFS a lightened Flywheel does not increase the power the engine produces, even the Manufacturers like ACT, Findanza and Stillen state that!!!!

Paul i dont care what your post count is, or how proudly you wear that sig on your chest, but im sorry in this case you are wrong, theres plenty of evidence out there thats says a lightened flywheel dosnt increase engine power - maybe worth reading and admitting you can be wrong at times?

 

http://www.tuning.wanadoo.co.uk/lightening.htm

http://www.se-r.net/engine/light_flywheels.html

http://www.nissanperformancemag.com/march03/ask_sarah/

 

infact just google for lightened flywheel

 

 

Chris, theres a very good reason the Stock Crank pulley weighs X lbs, its called engine harmonics, and it aint something you mess with unless a lot of research has went into it. Nissan didnt make the OE pulley that weight for nothing.

 

Ive been a lurker on this site for years, around Jap engines for over 20 years, am well known for building some of the top BHP builds in the UK so ive nothing to prove.

The only reason i have started posting - i was going to get trader status, no point in that now is there...

 

i think il go back to being a lurker, at the end of the day, it the real world that counts afterall.

a lightened fly-wheel/ud pulleys don't increase crank horsepower, they don't increase the intake charge or fuel delivery - required to produce more power. as said before they reduce the amount of power lost to the transmission, so you will see more power at the wheels when on the rolling road.

 

anyway brake horse power doesn't mean a great deal, all you should be interested in is the amount of torque your engine is producing, as it is this that makes the car faster.

I've pretty much got exactly the same mods and i am doing a dyno run tomorrow so i will let you know the outcome.

 

i've got pretty much the same mods as you stated......

 

heres my bhp.......

 

here.......

 

( the figure on the graph IS REAR WHEEL BHP, not flywheel bhp as the graph says....... its just what the software prints out ).....