E24 6 series Rolling Road Shootout
Printed From: Bavarian-Board.co.uk - BMW Owners Discussion Forum
Category: Technical & Model Specific Forums
Forum Name: The Big Coupé Forum
Forum Discription: for the older big coupés only (E24, CS, etc.)
URL: http://www.bavarian-board.co.uk/forum_posts.asp?TID=25706
Printed Date: 05-May-2024 at 13:05
Topic: E24 6 series Rolling Road Shootout
Posted By: Sohlman
Subject: E24 6 series Rolling Road Shootout
Date Posted: 06-January-2006 at 18:42
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First event of the year i am organising is now approaching. It's a six series rolling road shoot out as i am sure this has never been done before. If this proves to be successfull then i will go through or get someone else to organise one for each of the different models. The Venue is G Force Motorsport in Aylesbury The Date is Saturday 18th February 2006 Start time is 8am Numbers are limited to 15 cars although i will take another 5 to have on a reserve list in case of no shows. I have to send a deposit to the rolling road in about 10 days so will require some cheques from people allready signed up like now. The list so far 1. Me James (Sohlman) &nbs p; 635csi Artic Blue, Modified induction and Frits exhaust Manual car 2. Ross Harris with three cars: - M635csi Concourse Remapped 3. Ross Harris M635csi Standard 4. Ross Harris 635csi Standard Auto 5.Brian Jordan with two cars: - M635csi Standard 6.Brian Jordan M635csi Racecar heavily modified and around 350bhp 7.Graham Mitchel ; ; 635csi Standard auto 8.Dave Jerome 635csi highline with K&N induction, custom exhaust and chip remap 9.Ivan Tan Standard &nbs p; 635csi Auto 3 speed 10.Tone Crane & nbsp; & nbsp; 635csi with NOS Auto 11.Abbas &nbs p; &nbs p; &nbs p; M6 Highline Standard Currently i have classic cars magasine potentialy comming down to do a feature and will contact total and BMW car once i have paid a deposit. Spectators will be welcome although it will be cold. To check out the rolling road days credentials please have a look at their web site on: - http://www.g-force-motorsport.co.uk/ - http://www.g-force-motorsport.co.uk/ Anyone interested in comming to this should contact me ASAP by either PM or via mobile on 07946 517556 Happy New Year James -------------  Sunday 10th July Brooklands Sharkfest and Big Coupe Day. http://635csi.mysite.wanadoo-members.co.uk/ - Coupe Events
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Replies:
Posted By: GraemeH
Date Posted: 06-January-2006 at 19:07
| Run this passed me again. Rolling road shoot out? Excuse my novice ignoranc. ;-) |
Posted By: Sohlman
Date Posted: 06-January-2006 at 19:27
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A rolling road is a machine you strap your pride and joy to. Then an engineer runs the car on this machine and takes the car up to it's red line. This then records it's power and torque curve. The car is strapped down as it's like you or me being on a treadmill. The car is actually not moving, but on it's speedo it will be doing something around 140mph. A shootout is when you have a number of the same car going on the same set of rollers on the same day where they can be compared against one another. Hope this clears this up. James ------------- Sunday 10th July Brooklands Sharkfest and Big Coupe Day. http://635csi.mysite.wanadoo-members.co.uk/ - Coupe Events
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Posted By: GraemeH
Date Posted: 06-January-2006 at 19:35
| Sounds wild. Must admit makes me think of Dr Frankenstein! Not in a bad way, perhaps. But still feeling I want to shout out "It's Alive! It's Alive!" |
Posted By: AndyS
Date Posted: 06-January-2006 at 20:00
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What's the cost of this self-inflicted pain James? I'm interested but being at the other end of the country . . . ------------- AndyS Live each day as if it's your last - one day it will be. http://www.photostick.co.uk/view-933_BaurSig1.jpg" rel="nofollow"> 
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Posted By: Horsetan
Date Posted: 07-January-2006 at 06:42
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Mine's a four-speed auto, James, not a *snif* three-speed.... -------------   
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Posted By: Sohlman
Date Posted: 07-January-2006 at 08:32
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Sorry Ivan. My mistake. IVAN'S CAR IS A 4 SPEED The cost all in is £40 per car. For this you will get 30 - 40 mins on a rolling road with the engineer. The car will most likely get 2-3 runs untill an accurate figure has been achieved. Auto's take a lot longer as the kick down has to be deactivated. The water levels, oil levels are checked before the car goes on. As are the tyre pressures to ensure they are set at the correct level as this can affect readings. If the engineer has any doubts about the car he won't let it on as he does not want a car going bang on his roller. At the end of the day you will get a coputer print out detailing power at the wheels, estimated power at the flywheel, torque at fly and wheels and lamda readings throughout the runs. James ------------- Sunday 10th July Brooklands Sharkfest and Big Coupe Day. http://635csi.mysite.wanadoo-members.co.uk/ - Coupe Events
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Posted By: Horsetan
Date Posted: 07-January-2006 at 08:41
That's better -------------
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Sohlman wrote:
Posted By: 3.0csl
Date Posted: 07-January-2006 at 11:47
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James, I'm in, where do we send a cheque to? M635csi - standard.
Regards, Rohan ------------- Rohan Murphy 3.0 csl 2285146 3.0 csl 2275522 |
Posted By: Horsetan
Date Posted: 07-January-2006 at 13:41
Maybe we could travel up in tandem from Barnet, Rohan? -------------
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Posted By: 3.0csl
Date Posted: 07-January-2006 at 15:00
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Sure why not Ivan, good idea. Only started her for the first time in 4 months yesterday. Keen to take the injectors out and have them cleaned first. Regards, Rohan ------------- Rohan Murphy 3.0 csl 2285146 3.0 csl 2275522 |
Posted By: Horsetan
Date Posted: 07-January-2006 at 16:11
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Don't expect my car to be spotless. It spends much of its time at the stables, so lots of mud streaks, and an interior that smells of the stable.....mmmmmm..... -------------
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Posted By: Drew540i
Date Posted: 07-January-2006 at 20:17
Not really - just run it up in third gear or switch it to 'S'. Also switchable autos have no kickdown cable to disconnect! It should be stressed that automatics always give a vastly inflated power figure due to the lack of engine braking in an Auto. I don't know what dyno and power plot system G Force have though. Should be interesting! 
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Posted By: Sohlman
Date Posted: 08-January-2006 at 06:38
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What they need to do with the auto is to make it run in one gear for the entire duration of the run without changing down. When i spoke to them about this they said that they have been able to do a run with some cars, whilst others always try to kick down. It's with these cars that they disonect the ECU to the auto or deactivate the kick down so that a complete runs can be made. It also usually involves a second engineer hanging into the engine bay operating the throttle. I have seen then having all sorts of fun and games trying to get a run out of an E46 M3 with the SMG and traction as they could not get a run more than 250bhp because the traction thought the car was not moving and would cut power. Eventually they managed to deactivate the traction so that a run could be done. The owner was a little dissapointed mind you with the eventual figure of 302bhp as the car had only done 10K and had been remapped. ------------- Sunday 10th July Brooklands Sharkfest and Big Coupe Day. http://635csi.mysite.wanadoo-members.co.uk/ - Coupe Events
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Posted By: AndyS
Date Posted: 08-January-2006 at 06:59
Surely just switching to the 3-2-1 setting will lock the car in whichever gear & prevent kickdown taking place. As the transmission also has lockup in 3rd there will be engine braking - that's one of the things it's there for. ------------- AndyS Live each day as if it's your last - one day it will be. http://www.photostick.co.uk/view-933_BaurSig1.jpg" rel="nofollow">
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Posted By: Sohlman
Date Posted: 08-January-2006 at 07:38
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Theoretically yes, but if the kick down button is pressed the car will want to move down a gear and this is not what you want on the rollers as the figures will go all over the place. ------------- Sunday 10th July Brooklands Sharkfest and Big Coupe Day. http://635csi.mysite.wanadoo-members.co.uk/ - Coupe Events
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Posted By: Drew540i
Date Posted: 08-January-2006 at 08:17
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SMG is a different kettle of fish altogether as are
modern BMW's with traction control - because the front wheels are stationary and the rear ones are going round, the ABS sensors pick up on this and retard the timing, a by product of ASC+T as well as the current system. That's probably why the SMG system was having trouble. As for disconnecting the ECU and someone in the engine bay on the throttle, well that's just madness. We (well, my old Fella) ran a dyno for almost 20 years, developed the system that BMW(GB) use at Bracknell and did countless dyno runs on Automatic BMW's and never had to do any of that. Indeed, I can remember our dyno being calibrated and checked using a B plate 525i Automatic! Just leave it in third gear of as Andy so rightly said, switch it into 3-2-1. £40 for three runs is cheap enough though. It's worth doing because the dyno operator can look at things like mixture. |
Posted By: AndyS
Date Posted: 08-January-2006 at 10:32
Does the kick down still operate in 3-2-1 mode? I must go & check! I thought the whole point of this mode was that it gave total manual lock for the gear selected. Just a shame it's a 560 mile round trip for me  I would have loved to come. Maybe next time I'm down in Windsor . . .How much do they charge normally? ------------- AndyS Live each day as if it's your last - one day it will be. http://www.photostick.co.uk/view-933_BaurSig1.jpg" rel="nofollow">
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Posted By: Sohlman
Date Posted: 08-January-2006 at 12:40
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I think the normal fee is £120 an hour or around £400 for the day. Generally rollers are quite pricey, but getting a load of cars down makes things a lot cheaper. Tells you less, but you gets what you pay for in life. James ------------- Sunday 10th July Brooklands Sharkfest and Big Coupe Day. http://635csi.mysite.wanadoo-members.co.uk/ - Coupe Events
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Posted By: SFH3L
Date Posted: 09-January-2006 at 03:25
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James, I'll try to come along too - not sure in which car, but it will only be as a spectator, as I don't have an E24, although the way things are going I wouldn't put it past me (te he!). Hope to see you there. ------------- Sam. the original "not for profit" organisation. 
http://www.samleverifa.co.uk - Independent Financial Adviser In Buckingham http://www.samleverifa.blogspot.com - My Financial Blog |
Posted By: Jimbob
Date Posted: 09-January-2006 at 15:20
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Oi! My exhuast (blowing back box) and my oil drip (back of the head) won't be fixed in time, so no high rev runs for me - but I might make it as a spectator. *edit* by the way James, where do I send my fiver for the coupe register? ------------- And so says Jimbob. 1981 635csi 81k miles. Will be fixed, but not by me. |
Posted By: Drew540i
Date Posted: 10-January-2006 at 06:28
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Oi!
That's a poor excuse! The oil drip is either a cam cover gasket, or more likely a leaking oil pressure switch. The rear exhaust can be successfully bodged using 'red welding', fibreglass filler used for car bodywork. It sets rock hard and resists exhaust heat in centre boxes, never mind the (cooler) rear box. I rebuilt an E23 rear box with this stuff and it lasted almost 18 months........ Get it on the rollers! It'd be nice to see it, love the colour and the 14 inch Mahle rims - classic stuff. |
Posted By: Sohlman
Date Posted: 17-January-2006 at 17:55
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OK, We now have this day confirmed and Booked. I have now paid a sizable deposit I have 10 cars confirmed 8 deposits paid and awaiting 2 checks. I have 5 spaces left Total BMW will almost certainly be in attendance to cover the event as i now have a guaranteed 10 cars. See some of you there soon. James ------------- Sunday 10th July Brooklands Sharkfest and Big Coupe Day. http://635csi.mysite.wanadoo-members.co.uk/ - Coupe Events
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Posted By: 86C
Date Posted: 12-February-2006 at 19:24
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If I get the chance, I'd like to make it down to this, but only as a spectator. I'll be the odd bod in the old yellow Polo. (and a free bump for this post for those who've forgotten it!) |
Posted By: Sohlman
Date Posted: 13-February-2006 at 11:35
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NEWS FLASH Had a slightly bad day today. Having confirmed with G Force on Friday and then banked all cheque on Saturday for the rolling road day. Imagine my dissapointment when i am phoned on Monday to be told that G force wish to cancel the day due to their staff being on holiday. (As if they did not know that on Friday) (Please insert swear words hear) So not wishing to cancel the rolling road day i have spent all day today trying to sort out a new venue. Through grovling, pleading and bartering i have managed to secure a different rolling road for the day. Thats the good news. The bad news is that they will have to limit it to 10 cars which is fine as that is how many we have booked in now as i have had 1 cancellation. We will be sqeezed in around the other work they have on on that day. So the new venue is: - They have asked that all people arrive at 8:30 ready to start at 9am sharp. They welcome spectators and anyone is welcome to attend and you never know at the end of the day they may have time to do a couple more runs. For a map go onto http://www.multimap.com - www.multimap.com and type in the above postcode. For general directions follow the signs for Uxbridge and then follow the signs for the industrial estate which i am told is well sign posted and you can't go to far wrong. If anyone has any questions please feel free to call me PM me and i will give you my mobile number. People booked in and paid are: -
------------- Sunday 10th July Brooklands Sharkfest and Big Coupe Day. http://635csi.mysite.wanadoo-members.co.uk/ - Coupe Events
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Posted By: Robmw
Date Posted: 13-February-2006 at 14:51
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James ,
Well done at such short notice . Power Engineering have a good rep with the Ford Cosworth brigade ------------- Robert Born |
Posted By: Horsetan
Date Posted: 13-February-2006 at 17:46
Anyone else wanting to come and see the old girls shaking their booty is free to come and have a look  -------------
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Posted By: RossM6/635
Date Posted: 18-February-2006 at 14:38
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Well done James , a great morning seeing how the old girls performed . And also well done Power Engineering .
------------- Ross |
Posted By: Horsetan
Date Posted: 18-February-2006 at 19:32
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And here are some of the usual suspects, waiting their turn on the rollers.....
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Posted By: Sohlman
Date Posted: 19-February-2006 at 05:36
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Please find the results of the day below. I have tried to work out flywheel figures for the cars which are always a little bit hit amd miss due to most of the cars being auto's, but the rear wheel figures are acurate. On the 3 manual cars the transmission losses ranged from 20% to 29% http://www.bmwcarclubforum.co.uk/uploads/Sohlman/DYNO_DAY_spreadsheet.xls - DYNO_DAY_spreadsheet.xls Was very pleased with my results. 159bhp at wheels 222bhp at flywheel and 256ft/lbs or torque. When went there last year i achieved 207bhp at flywheel and 246ft/lbs of torque. So the induction system i designed and made and the Fritz manifold between then has given a 15bhp improvement in power and 10ft/lbs increase on torque and the car has done 18,000 miles between runs so should be worse rather than better. I hope all that went enjoyed the day, although it is clear that some cars need some work. James ------------- Sunday 10th July Brooklands Sharkfest and Big Coupe Day. http://635csi.mysite.wanadoo-members.co.uk/ - Coupe Events
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Posted By: Brucey
Date Posted: 19-February-2006 at 06:07
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Thanks for organising this James, all a bit of a hoot. I have been wondering about the vexed subject of transmission losses; I wonder if they are much different for auto cars? If not then we had a lot of cars that didn't get close to stock power output, and the best auto 635CSi (which has been remapped and only has 75 K on the clock) still didn't quite make stock power, where I'd have guessed ~230bhp ought to be on the cards.... My own 150000 mile specimen sounded (and for a change also looked) better than it went, ho hum.... but at least it didn't smoke too heavily; I thought poor Ivan was going to have a heart attack.... Incidentally my chum Mark is presently ignoring his wife and child in order to compile a load of stills and video of the day (about 250MB so far). I will make copies on a CD for anyone who wants one. If anyone has further pictures I can add them to the compilation disc, just PM me and then post me your disc (not broadband yet...) cheers
------------- ~~~~~~~ Brucey ~~~~~~ |
Posted By: 3.0csl
Date Posted: 19-February-2006 at 07:16
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James, thanks for the day, it was very good fun and worthwhile. As james noted in the spreadsheet we headed back to Bird's place where Phil operates out of and he very kindly had a look at my car. We found that with the pedal fully down the throttle was not fully open and had about 1/3" left to travel. Having gone on a trip last night I can confirm that the car has been transformed and I can't wait to get it back on the rollers. regards,
Rohan ------------- Rohan Murphy 3.0 csl 2285146 3.0 csl 2275522 |
Posted By: 286bhp
Date Posted: 19-February-2006 at 08:56
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Rohan,
glad to note you can feel the difference, as you said , can't wait to see her back on the rollers. Regards Phil ------------- '01 M5 '02 MB C220 Turbosmoker '99 323i (sold ) '89 M3 220hp with shrick 284's '73 2002 cab it's an Illness ...... |
Posted By: 3.0csl
Date Posted: 19-February-2006 at 11:18
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Phil, I can really feel the difference up the top. It was good fun last night experimenting with it! Might book her on the rollers somewhere next weekend! Will et you know how i get on. Very grateful for you having a look at her and finding the problem. Regards,
Rohan ------------- Rohan Murphy 3.0 csl 2285146 3.0 csl 2275522 |
Posted By: Horsetan
Date Posted: 19-February-2006 at 11:36
Oh thanks
It seems to be hereditary, so I'm probably due a major one in 10 years' time. Better start taking the Simvastatin.....
OK, I'll have one then!
You'll find a limited number of pics in http://www.bmwcarclubireland.com/gallery/thumbnails.php?album=147 - THIS GALLERY Here's the nitrous-fitted one:
...whilst this one was amusing:
-------------
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Posted By: Drew540i
Date Posted: 19-February-2006 at 12:09
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It's around 40% on an automatic. The other problem
is that automatics don't have engine braking so getting 'real' figures is very hard. 145 bhp at the wheels is about 200 flywheel. But, how many of you were running Shell Optimax? These engines were designed a very long time ago to run on 99 Octane fuel, not the 95 Octane crap you guys were probably using!
I daresay you lost a good 10 bhp running 95 fuels. For example, the much maligned E36 M3 Evo which 'never does 321 bhp' will in fact make it's money with decent fuel. Run it on 95 and it will lose around 20 bhp. As for Ivan's car, I would imagine this was a problem with the crankcase breather. It certainly didn't smoke when he drove up the road - I had the same problem with a 528i E28. His low power figure was due to the fuel octane being further (dramatically) reduced by oil burning. Generally though, 25 year old engines don't like too much 5500 rpm action tho! 
Good day all round though - well done Mr Sohl. |
Posted By: Horsetan
Date Posted: 19-February-2006 at 12:15
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Not me. I topped up my LRP (Sainsbury's 97 RON), but to ensure proper poisoning of you lot
98.
My engine was having a "senior moment" I received a phone call in the evening from a certain someone who reckoned I'd be better off using 20w-50 oil rather than 10w-40....
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Posted By: UKDaveJ
Date Posted: 19-February-2006 at 12:22
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Thanks to James & Power Eng, I really enjoyed the day, but am now somewhat confused having read through the excel doc of figures. James, your figures indicate 63bhp loss with a manual box. Mine, an auto Highline, shows est 57bhp loss. In fact, using the 'assumption' conversion multiplication for auto flywheel figs based on their genuinely achieved at the wheel figs, also adds to the confusion. The average auto loss equates to 54 bhp (only the Nos run figures ignored), which doesn't make sense. Yet, your manual James was showing 63bhp loss.......??!! The auto's have to be losing more power than the manuals I'd have thought, thereby actually pushing up their estimated flywheel figures to 200bhp+. I'm now confused. ------------- My 635's.  
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Posted By: Horsetan
Date Posted: 19-February-2006 at 12:30
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Not as confused as me. I don't know whether it's the crankcase breather, or whether I need a new bottom end -------------
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Posted By: Sohlman
Date Posted: 19-February-2006 at 12:38
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With the figures the only car i did not have a rear wheel figure for was mine. Typical. I remember it being 159 on the guage on the dyno, but did not see the computer screen figure due to it being manual they worked out the figures including losses. So i used the 159 for purposes of comparison it was probable a little higher than this as it was with the all the auto's. I then worked out what i had to multiply this by to get 222bhp. Then i took this scalling factor 1.4 and multiplied all the auto figures by this to give a like for like comparison of flywheel power as this is what we understand. So basically i have multiplied your wheel figures by 40% which should be about right. How acurate they are i can't say, but they are just there to give an idea. They are a lot lower than i was exspecting i have to be honest. James ------------- Sunday 10th July Brooklands Sharkfest and Big Coupe Day. http://635csi.mysite.wanadoo-members.co.uk/ - Coupe Events
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Posted By: UKDaveJ
Date Posted: 19-February-2006 at 12:39
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You need to probably get a leakdown test done Ivan, there is a procedure on bigcoupe forum for this - you could use a compression tester initially just to get an idea, but it won't be as thorough as the ld!
------------- My 635's.
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Posted By: 86C
Date Posted: 19-February-2006 at 13:06
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Good to meet some of you guys yesterday. Just need to find my own E24 now so I'm not the oddball with the Polo at these meets Not in any hurry though... The right one will come along eventually |
Posted By: Brucey
Date Posted: 19-February-2006 at 14:16
me too... I reckon the white 75k auto highline should have been making about 230bhp- its been chipped and there is more to be had on one of these. I guess we'll never know now, but I suspect that the auto transmission losses may have been higher than the manual ones. We might be able to work it out from Tony's nitrous car- he had 150bhp jets in, but we only saw a fraction of that as a power increase on the giggle gas. My car has been timed 0-60 and is a little quicker than stock (despite the weight of the AC etc), so I doubt it is far away from stock power output, I was expecting about that or a touch more. BTW I filled up with 3/4 optimax, 1/4 95 octane. No comparative measurement available, and felt no difference through the 'backside dyno' whatsoever.... cheers
still, all a bit of a hoot ------------- ~~~~~~~ Brucey ~~~~~~ |
Posted By: Horsetan
Date Posted: 19-February-2006 at 14:22
Suddenly, that explains everything -------------
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Posted By: Brucey
Date Posted: 19-February-2006 at 14:51
there is quite a nice-looking '87 auto in red on e-bay right now, complete with style 32 alloys, and 107K on the clock. The tyres look funny sizes, but other than that it looks like a nice car. http://cgi.ebay.co.uk/1987-BMW-635-CSI-AUTO-RED_W0QQitemZ4614972341QQcategoryZ31357QQrdZ1QQcmdZViewItem - http://cgi.ebay.co.uk/1987-BMW-635-CSI-AUTO-RED_W0QQitemZ461 4972341QQcategoryZ31357QQrdZ1QQcmdZViewItem cheers
------------- ~~~~~~~ Brucey ~~~~~~ |
Posted By: Drew540i
Date Posted: 19-February-2006 at 15:18
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Here's a reply I had from Geoff about Ross's low
powered red M6 and the possible cause of the problem.... " One thing that I would check is that the full load switch is working. Big rpm and 0.3 % CO sounds like part load operation . The idle/full load switch has a 3 pin plug. Centre is common . Pull the plug rubber boot back and put a meter down the back of the plug on one of the outside pins ( plug connected to switch ) Ignition on -Operate the throttle . If it moves volts immediately that the idle connector. Move to the other outside pin and try full throttle. Should get the same meter response as idle. See what happens . I have replaced loads of those idle/full load switches for full load switch failure !!! The idle switch is a microswitch- you can hear it going on off. The full load is a wiping contact type and it stops wiping !!! Who knows £15 for loads of bhp !! See if the switch thing makes sense but I think that could be the reason for p*ss poor fueling. The late M6s were calibrated a bit different to the originals so a rechip could be a plan even with the switch working." There you go Ross - a plan could be to take the car to Ray at West Tuning (Thruxton 01264 773839) who does stuff with Geoff on the dyno most of the time. Sorting the mega weak running and a rechip is all very possible. Feel free to PM me for a chat about stuff!
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Posted By: UKDaveJ
Date Posted: 19-February-2006 at 15:51
Looks nice! Missing the rad fan-shroud, also in the close up shot of the osf wheel you can see what looks like overspray on the mudshield!  ------------- My 635's.
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Posted By: UKDaveJ
Date Posted: 19-February-2006 at 17:37
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I thought the following of interest. http://neptune.spacebears.com/opine/horsepwr.html - HERE According to my Highline's owners manual, it's rated at 211 bhp (DIN 70020 standard) at 5700 rpm. Achieving a rear wheel figure of 142bhp at 5226 rpm equates to about a 32% loss, considerably more than indicated in the link above, which suggests 20% loss for auto transmission. That would have improved things a bit, 169bhp! ------------- My 635's.
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Posted By: AndyS
Date Posted: 19-February-2006 at 17:49
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Glad you all enjoyed it, shame I couldn't make it. One thing that should be borne in mind is that the figures obtained were for that dyno (& to a much lesser extent, that day). Dynos, like engines, do differ & that one could have been under reading slightly. This is why it's important to use the same dyno when measuring before & after mods. Differing atmospheric conditions can give differing results too. The one constant is that the figures obtained can be compared to the other cars tested. I remember a figure of 30% being mentioned for transmission losses so 40% isn't too far off. Don't forget these autos have lockup so don't lose as much power as older types. Remember, when Total BMW did a group test with some E30's no standard car matched the manufactures figure. ------------- AndyS Live each day as if it's your last - one day it will be. http://www.photostick.co.uk/view-933_BaurSig1.jpg" rel="nofollow">
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Posted By: Horsetan
Date Posted: 19-February-2006 at 18:14
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Given that I poisoned everyone yesterday, this explains a lot -------------
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Posted By: Drew540i
Date Posted: 19-February-2006 at 18:48
Yes, up to a point but even an old system like Motronic 3 does (sort of) take Barometric pressure into account - it will do more power on a really cold damp though. Ye cannae beat the law of physics! It was in fact a chilly day and the doors of the dyno cell were wide open. At the end of the day, 211 bhp was on an engine dyno with a perfect new engine and was the best of numerous runs. The M30 is a prehistoric thing used to power Heinkel bombers in WW2 and 200 bhp is about your lot for a decent standard one. As for the E30 dyno shoot out you mention, a few cars did get within 5 bhp of the standard figure - namely the standard unmolested ones. |
Posted By: Drew540i
Date Posted: 19-February-2006 at 18:58
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A 20% power loss through an old 4HP22 is just
dreaming - when these were being run up they were in 3rd gear only without the converter lock up. Trust me - these cars were doing around 200-210 bhp! Nothing disgraced itself and had there been a converter lock up in the lower gears, they would have shown more power. |
Posted By: Brucey
Date Posted: 20-February-2006 at 00:45
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hmm, 'old' motronic 3??? Most of the cars there were running motronic 1.0... just temperatures and airflow, and even on the M30 engine, a WOT fuelling strategy that relies on the throttle sensor working OK. We had a good mix of stock and slightly modified engines; if there had been a few outliers then fair enough, but all the auto gearbox cars were well down on rear wheel bhp which points to the conclusion that the transmission losses were very large, especially when they are as quick or better than stock on the road, i.e. auto slower than manual. I was trying to figure out a way of using the top gear lock-up to make it more efficient; thing is, it would have tried to kick down at any speed below about 140mph on the rollers.... cheers
------------- ~~~~~~~ Brucey ~~~~~~ |
Posted By: UKDaveJ
Date Posted: 20-February-2006 at 04:52
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So, even the figures achieved at the rear wheels on the auto cars were not with transmission lock, therefore more bhp would have been possible had the lock been in place??!! I've never had an auto car on the rollers before, so it was quite an experience. If the auto cars were run through the box (as normal) but without hitting the point on the throttle where the kick-down switch operates, would they still have got to a WOT position in 4th & therefore potentially higher rear-wheel figure as the transmission would have locked out? On mine, you can easily tell when you are about to kick down, the throttle feels quite stiff (like its reached max downward travel), that extra push will cause the kick-down to operate. I'm not disappointed with the results, far from it, just was wondering having looked at the figures how James' manual 635 showed such apparent massive transmission losss, considerably more than that of the speculated 'flywheel' figures of the autos in comparison with their achieved rear wheel achieved figures. I hadnt realised that the transmission didn't lock up in 3rd, therefore more would have been capable from the auto's as Drew540i indicates had they locked! Was this lack of tranmission lock partly to explain why the torque figures seemed quite low on some of the auto cars, mine showed 168lbs/ft on the graph at 4000rpm then tailed away massively? I think all the cars ran well with very few exceptions & they were either due to age, mileage or need for some garage fettling. According to my Road Angel GPS speed readout, myself, Craig & rpmMark were making very good 3 figures progress up the M40 on the way home.......... My graph  ------------- My 635's.
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Posted By: UKDaveJ
Date Posted: 20-February-2006 at 08:18
Interesting! How come James's manual 635 showed 159bhp at the wheels & 222bhp at the flywheel? Thats a massive loss through the transmission (near as dammit 28%), not far off what the auto's seemed to theoretically lose? Does the dog-leg manual box really lose that much in comparison to the auto box? ------------- My 635's.
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Posted By: AndyS
Date Posted: 20-February-2006 at 09:12
It does. Once the gear has engaged the clutch locks up to avoid torque convertor slip. This is not the same as using the 3-2-1 position to lock a gear. This is one of the reasons the auto has such good economy & performance not far short of the manual & was a major improvement over the 3 speed predessor. At a steady speed in 3rd there would be no more slip than with a manual. I have seen no figures to suggest the 4HP22 in 3rd gear would have higher losses than the manual in 3rd or 4th. There is is good article from a transmission specialist on the net about the 4HP22 transmission which I found from the Roadfly forum, going into great detail about the design. The Highlines used a later version of Motronic - 3.3 iirc. ------------- AndyS Live each day as if it's your last - one day it will be. http://www.photostick.co.uk/view-933_BaurSig1.jpg" rel="nofollow">
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Posted By: AndyS
Date Posted: 20-February-2006 at 09:34
The flywheel power wasn't measured - you can only do that by removing the engine & strapping it to an engine dyno. The flywheel power was estimated from the estimated transmission power losses. In fact the bhp figure was obtained from the torque at the rear wheels - lb/ft, newton/metres, kg/m whatever. It was then converted to "brake horse power" which, simply put, is torque x revs. Huge power Yank engines were quoted using SAE which meant using an engine dyno without ancillaries such as alternators, power steering pumps etc. Once in a car it was a whole different story. So, given that you can't be 100% sure of the flywheel power, have no guarantee that the engine produced the full 218 or 220 Highline power (211bhp was from the E34 535) when it was new let alone with 100k miles under it's belt or indeed the accuracy of the rolling road, it's difficult to quote absolutes. What you can say is that on that dyno that Six gave Xbhp at the wheels compared to the other Sixes that were tested too. From the torque & power curves you can see where flat spots or other problems are occuring - as some of you found out. ------------- AndyS Live each day as if it's your last - one day it will be. http://www.photostick.co.uk/view-933_BaurSig1.jpg" rel="nofollow">
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Posted By: Sohlman
Date Posted: 20-February-2006 at 10:53
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I will post up my power figure soon. I just have to scan the sheet in. The curve is now much flatter and does not have a dip which it had on the last run and power and torque are up right the way across the dyno run. 29% transmission loss for my car sounds about right as the gearbox is a little tired as is leaking slightly. I have a spair mind you. For reference my car has the overdrive box and not the dog leg. James ------------- Sunday 10th July Brooklands Sharkfest and Big Coupe Day. http://635csi.mysite.wanadoo-members.co.uk/ - Coupe Events
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Posted By: UKDaveJ
Date Posted: 20-February-2006 at 11:29
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Thanks Andy & James, most interesting! I for one would definitely like to see more graphs, then its possible to work out other details from them. Figures on their own only give one part of the overall picture. I think my torque figs might well be down due to a blowing manifold, but other than that I don't know. To participate in this exercise was one thing, to usefully learn from it is quite another!! ------------- My 635's.
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Posted By: brybusa
Date Posted: 20-February-2006 at 11:42
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Interesting that on the day the rear wheel 159BHP wheel bhp figure equated to a calculated 222BHP, when my E34 535 manual (re-mapped)car was dyno'd @ G - Force the rear wheel figure was 160BHP and the fly figure estimated was 205BHP... I cant see a chipped 3.5 making 230BHP IMHO
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Posted By: UKDaveJ
Date Posted: 20-February-2006 at 11:48
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Here's a fun link for you!! http://www.torquecars.co.uk/Tuning/engine-mods-power-gain-calculator.php - HERE ------------- My 635's.
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Posted By: 286bhp
Date Posted: 20-February-2006 at 11:53
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Very interesting, I specce'd up a B10 3.5 E34 , it came up with pretty much the same figure Alpina claim - 260 bhp!!! give or take 5bhp !! I wonder if it will take into account leggy engines like the one in my '02 !
Excellent link ------------- '01 M5 '02 MB C220 Turbosmoker '99 323i (sold ) '89 M3 220hp with shrick 284's '73 2002 cab it's an Illness ...... |
Posted By: UKDaveJ
Date Posted: 20-February-2006 at 13:05
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I got....... Approximate power after modifications have been added. 426.514bhp ------------- My 635's.
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