Transmission Losses Cammed Vts's

1. VTSTomE Established Member Joined: Apr 2008 Hereford Posts: 1381 Indigo 16v Rallye + 2 VTS's

   #1 19th March 2009, 08:46

   Recently had my car mapped to 158 bhp at the fly but only 110 atw. What has anybody elses come out? Is this a normal transmission loss as its about 30%?
2. Ryanp Super Moderator Joined: Feb 2004 Tonbridge United Kingdom (England) Posts: 38236 Vtr, 172, throttle bodied track slut

   #2 19th March 2009, 10:41

   on MAHA rollers ja?
3. VTSTomE Established Member Joined: Apr 2008 Hereford Posts: 1381 Indigo 16v Rallye + 2 VTS's

   #3 19th March 2009, 10:50

   Dont kknow what your on about mate sorry?!
4. Ryanp Super Moderator Joined: Feb 2004 Tonbridge United Kingdom (England) Posts: 38236 Vtr, 172, throttle bodied track slut

   #4 19th March 2009, 10:51

   They are the type of Rollers used.
   
   Mahas/dyno dynamics etc..
5. VTSTomE Established Member Joined: Apr 2008 Hereford Posts: 1381 Indigo 16v Rallye + 2 VTS's

   #5 19th March 2009, 10:58

   Im not to sure mate but what difference would it make tho? I know different rollers read different but the losses should theoretically still be the same %?
6. Ryanp Super Moderator Joined: Feb 2004 Tonbridge United Kingdom (England) Posts: 38236 Vtr, 172, throttle bodied track slut

   #6 19th March 2009, 11:00

   Dyno dynamics use a standard transmission loss 15-20% iirc.
   
   MAHAs are meant to calculate the tranny loss on run down by themselves.
7. VTSTomE Established Member Joined: Apr 2008 Hereford Posts: 1381 Indigo 16v Rallye + 2 VTS's

   #7 19th March 2009, 11:02

   So i take it mahas are better
8. Ryanp Super Moderator Joined: Feb 2004 Tonbridge United Kingdom (England) Posts: 38236 Vtr, 172, throttle bodied track slut

   #8 19th March 2009, 11:23

   They are more respected in the industry it seems.
   
   However if not calibrated correctly still not accurate. Why everyone takes RR figures with a pinch of salt
9. jpsaxo Saxperience Post Whore Joined: Oct 2005 Sydney Posts: 8525 Mango Westcoast

   #9 19th March 2009, 11:33

   as long as it feels good on the road mate thats all that matters!
10. VTSTomE Established Member Joined: Apr 2008 Hereford Posts: 1381 Indigo 16v Rallye + 2 VTS's

    #10 19th March 2009, 12:02

    She sure ticks that box!
11. Xsi16v_Jk Established Member Joined: Nov 2007 Hereford Posts: 1090 S2 Rallye ITB. Seat Leon FR. Clio 182FF. XSi 16v

    #11 19th March 2009, 12:04

    Agrees on that one lol
12. dj_russell Established Member Joined: Mar 2009 in shell with personal v-power pump lol. Posts: 2197 400bhp build gt4

    #12 19th March 2009, 14:13

    what modss you ghad done apart from the obvious.
13. user_31642 Established Member Joined: Mar 2009 s-o-t Posts: 1174 S2 106 Rallye

    #13 19th March 2009, 18:43

    gotta feel good!! what cams you runnin mate by the way ? ?
14. gouldy87 Saxperience Forum Bum Joined: Jun 2008 Posts: 3932

    #14 19th March 2009, 20:21

    on maha rollers un mapped - 136.5 at fly 101 @ wheels iirc. someone worked it out for me at the sax-p yorkshire rolling road day and i had the least transmission loss of the day. iirc it was about 15%
15. Ryanp Super Moderator Joined: Feb 2004 Tonbridge United Kingdom (England) Posts: 38236 Vtr, 172, throttle bodied track slut

    #15 19th March 2009, 20:22

    Transmission losses will allways be effected by
    1. how well the rollers are set up
    2. Tyre pressues
    3. State of gearbox driveshafts etc..

    1 user thanked this post: evans1089
16. Xsi16v_Jk Established Member Joined: Nov 2007 Hereford Posts: 1090 S2 Rallye ITB. Seat Leon FR. Clio 182FF. XSi 16v

    #16 19th March 2009, 20:37

    Learn something new everyday cheers ry
17. gouldy87 Saxperience Forum Bum Joined: Jun 2008 Posts: 3932

    #17 19th March 2009, 20:51

    i heard about tire pressures and gear box condition when we were at the rolling road day. its mad as to what can throw your BHP all over the place tbh. things like the air temperiture and humidity can affect it too
18. dannygti Saxperience Post Whore Joined: Feb 2006 dudley United Kingdom (England) Posts: 6790 106 gti/ SEAT LCR

    #18 19th March 2009, 20:56

    more power = more restriction = more power loss at wheels.
19. williamsvts Saxperience Post Whore Joined: Feb 2006 northumberland Posts: 7693 pulsar gtir, mk4 astra sxi

    #19 19th March 2009, 20:56

    mine was 127 @ wheels and 153 @ fly at chipwizards.
20. KamRacing Saxperience Addict Joined: Nov 2006 A farm shed in Aylesbury Posts: 14916 Corolla AE86 Peugeot 205 B18C (in bits)

    #20 19th March 2009, 21:56

    the only way to accurately measure transmission loss is to get the car on a RR and then onto an engine dyno and compare the 2 figures. not exactly practical
    
    If you are after an approximate figure then do your own calculations from the wheel figure and assume a 15% transmission loss. It won't be that far off the mark
    
    .. and if you have a 30% transmission loss then your tyres are probably flat lol
21. Toad Saxperience Post Whore Joined: Mar 2007 Reading Posts: 8980 French tin can

    #21 19th March 2009, 22:09

    Quote:

    Originally Posted by williamsvts mine was 127 @ wheels and 153 @ fly at chipwizards.

    Ha! I got the same result from Wayne, and I mean EXACTLY the same result. Since then, I've had a BV head installed, cam timing adjusted, it's much quicker, yet, after all that, the MAHA rollers said I had 158 at the fly and only 112 atw.
22. gouldy87 Saxperience Forum Bum Joined: Jun 2008 Posts: 3932

    #22 19th March 2009, 22:15

    what dyno has wayne got?
23. KamRacing Saxperience Addict Joined: Nov 2006 A farm shed in Aylesbury Posts: 14916 Corolla AE86 Peugeot 205 B18C (in bits)

    #23 19th March 2009, 22:46

    Quote:

    Originally Posted by Toad Ha! I got the same result from Wayne, and I mean EXACTLY the same result. Since then, I've had a BV head installed, cam timing adjusted, it's much quicker, yet, after all that, the MAHA rollers said I had 158 at the fly and only 112 atw.

    some RRs allow you to input the transmission loss which would give you a bigger fly figure the more you add ...there are many ways to 'massage' the final figures given
24. gouldy87 Saxperience Forum Bum Joined: Jun 2008 Posts: 3932

    #24 19th March 2009, 23:24

    mahas the most accurate then?
25. Ryanp Super Moderator Joined: Feb 2004 Tonbridge United Kingdom (England) Posts: 38236 Vtr, 172, throttle bodied track slut

    #25 19th March 2009, 23:29

    Quote:

    Originally Posted by gouldy87 mahas the most accurate then?

    Meant to be, but as with any RR. They can still be inaccurate.

    1 user thanked this post: gouldy87
26. williamsvts Saxperience Post Whore Joined: Feb 2006 northumberland Posts: 7693 pulsar gtir, mk4 astra sxi

    #26 20th March 2009, 20:24

    Quote:

    Originally Posted by Toad Ha! I got the same result from Wayne, and I mean EXACTLY the same result. Since then, I've had a BV head installed, cam timing adjusted, it's much quicker, yet, after all that, the MAHA rollers said I had 158 at the fly and only 112 atw.

    ive changed most of my engine aswell, need to dial my cams in properly but the car pulls alot harder than it used to.
27. Ryanp Super Moderator Joined: Feb 2004 Tonbridge United Kingdom (England) Posts: 38236 Vtr, 172, throttle bodied track slut

    #27 20th March 2009, 21:00

    Quote:

    Originally Posted by williamsvts ive changed most of my engine aswell, need to dial my cams in properly but the car pulls alot harder than it used to.

    does it suck like a 16 year old on her first cock?
28. Barry123 Saxperience Hardcore! Joined: Oct 2005 Aycliffe Posts: 32205 Saxo VTS

    #28 20th March 2009, 21:05

    The higher the revs the higher the losses/resistance in the engine.
    
    similarly the higher the rotation speeds of the components are, the higher the losses as a result. Which is why percentage is a useless figure to apply to the transmission losses, the losses tend to be more exponential.
    
    fin.
    
    Maha's have the right approach, but I still dont believe the fly figure in the slightest.
29. Toad Saxperience Post Whore Joined: Mar 2007 Reading Posts: 8980 French tin can

    #29 21st March 2009, 20:44

    I just want to get some proper cams in. No more of this 112atw malarky...
30. KamRacing Saxperience Addict Joined: Nov 2006 A farm shed in Aylesbury Posts: 14916 Corolla AE86 Peugeot 205 B18C (in bits)

    #30 22nd March 2009, 01:37

    Quote:

    Originally Posted by adsayer The higher the revs the higher the losses/resistance in the engine. similarly the higher the rotation speeds of the components are, the higher the losses as a result. Which is why percentage is a useless figure to apply to the transmission losses, the losses tend to be more exponential. fin. Maha's have the right approach, but I still dont believe the fly figure in the slightest.

    how do the maha's calculate transmission losses. I'd hope not using coast down which is a majorly flawed method.
    
    have a read on puma racing website
    http://www.pumaracing.co.uk/coastdwn.htm
    
    15% loss for FWD is to me a decent rule of thumb.. Puma has another method of
    Wheel BHP + 10bhp fivided by 0.9