Power Loss At Universal Joint

johnny yuma · 28 Apr 2006, 05:56 (Ref:1596696)

Due to firewall,transmission tunnel etc. constraints [laziness?] I have about a 5 degrees angle [off a straight line]at the front uni in a rwd live rear axle sedan with engine swap. Am I losing much power--is it worth chasing ??

graham bahr · 28 Apr 2006, 06:57 (Ref:1596712)

no you will hardly loose anything, infact u/j s should not run perfectly in line or they wear permaturely

johnny yuma · 28 Apr 2006, 12:19 (Ref:1596884)

Quote:

Originally Posted by graham bahr

no you will hardly loose anything, infact u/j s should not run perfectly in line or they wear permaturely

thanks graham one less niggle.

Team27 · 28 Apr 2006, 13:31 (Ref:1596950)

On the subject of losses is there any equation to calculate the losses of power when angling driveshafts which use tripod joints?

Is it to much of a worry compared to CofG reduction. This is in the case of a single seater

norman-normal · 30 Apr 2006, 01:44 (Ref:1597873)

Power losses due to taking a round about way to the road will surprise you. the most efficient is is the common chain driven motorcycle because the engine rotating in tandem with driven wheel, same for the Morris 750 with transverse engine. An average car ft engine rear wheel drive will suffer about a 40% loss. The same set up on a buss with an extra long drive shaft will be closer to 60%. DON'T BELIEVE IT? prove it to yourself: take an impact wrench or a torque wrench set at say a 40 ft pound setting and tighten a lug nut, then with a torque wrench, see haw much is required to remove it. then do the same with longer extension, the add a U-joint, then another extension and hold it at an angle. You will be amazed at the difference.

graham bahr · 30 Apr 2006, 08:20 (Ref:1597990)

yes norman i see what your saying but the question was about a slight 5degree angle (which is how they are designed to run), your compairing a short direct straight drive without a U/J to one with a much longer drive with a u/j, not to mention the u/j s in a socket set arn't designed to be free running not being on needle rollers

norman-normal · 30 Apr 2006, 14:38 (Ref:1598160)

Quote:

Originally Posted by graham bahr

yes norman i see what your saying but the question was about a slight 5degree angle (which is how they are designed to run), your compairing a short direct straight drive without a U/J to one with a much longer drive with a u/j, not to mention the u/j s in a socket set arn't designed to be free running not being on needle rollers

True, even so it's a item that is often missed. BTW are they using any aluminum or carbon fiber drive shafts over there?

graham bahr · 30 Apr 2006, 15:54 (Ref:1598195)

steel mainly!

norman-normal · 1 May 2006, 04:38 (Ref:1598492)

Oh! thats terrible! I feel so sorry for you. My Aunt has one on her car and she doesn't drive any more. Would you accept a gift?

johnny yuma · 1 May 2006, 05:56 (Ref:1598512)

Quote:

Originally Posted by norman-normal

Oh! thats terrible! I feel so sorry for you. My Aunt has one on her car and she doesn't drive any more. Would you accept a gift?

Is she The Little Old Lady from Pasadena ?

Rubinho · 1 May 2006, 13:07 (Ref:1598747)

Quote:

Originally Posted by norman-normal

An average car ft engine rear wheel drive will suffer about a 40% loss.

Absolutely no way near this much. From here:

Quote:

Originally Posted by http://www.pumaracing.co.uk/power3.htm

Average real transmission losses are about 10% of the flywheel power plus 10bhp for FWD cars and 12% plus 10bhp for RWD cars. This equates to about 15% to 17% for cars of "average" power output.

VW technical also quote their cars as losing, on average, about 15% of the flywheel power in the transmission and tyres.

The chassis dyno division of Bosch UK also suggest 15% as being a realistic estimate of transmission losses.

norman-normal · 1 May 2006, 14:48 (Ref:1598789)

I drew my own conclusions using one of the first dynos in So Cal (no scientific method), autos used were American w/auto trans judged against "factory HP claims" at the time. (mid to late 50s) The factory HP claims in those days were a bit fancifull.... Please forgive me.

norman-normal · 1 May 2006, 14:54 (Ref:1598793)

Quote:

Originally Posted by johnny yuma

Is she The Little Old Lady from Pasadena ?

Yes Johnny, shes riding a Harley now, dressed in black from helmet to boots

**dtype38** · 1 May 2006, 20:17 (Ref:1598967)

Quote:

Originally Posted by Rubinho

Absolutely no way near this much. From here:

Yeh, got to agree there. I just got off the rolling road with my car and it posted 184kw at the engine and 150kw at the wheels. That makes a 34kw transmission loss, or just over 18% of the engine power. I also know that Jaguars tend to be at the high end of these type of losses (for whatever reason). What always amazes me is that it's the equivalent of the mechanical drive train acting like ten three-bar electric fires... no wonder it gets hot

graham bahr · 1 May 2006, 21:46 (Ref:1599008)

my car looses about 18% through the transmission despite the engine shoving 460bhp through it, the direct top gear probably saves some looses but then again 235 sticky slicks will increase the losses again

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
sad loss	motorsportmarshal61	IRL Indycar Series	1	26 Mar 2006 20:59
Supertrapp's / power loss	R59	Racing Technology	16	29 Dec 2005 14:50
Loss	MADDOG-99	Formula One	15	27 May 2004 10:43
Loss of Engine Air	903cc	Formula One	27	9 Jun 2003 00:52
Universal Sadness	floid2000	ChampCar World Series	1	13 May 2000 18:45