Ditching the AFM |
Post Reply | Page 123> |
Author | ||
AndyS
Really Senior Member II The Last of the Few Joined: 21-August-2003 Location: 55 � North Status: Offline Points: 1365 |
Topic: Ditching the AFM Posted: 30-June-2006 at 19:56 |
|
Another area of the AFM which is a bit u/s is the routing of the "cold" air feed right above the exhaust manifold! Not only that, but it changes diameter a couple of times too.
James Sohl engineered a better system which proved it's worth on the TBMW rolling road day. Why didn't the air feed come from the n/s of the engine bay? Surely it would have only entailed turning the AFM around 180 degrees. |
||
Sponsored Links | ||
Drew540i
Really Senior Member II Available from all good newsagents! Joined: 15-August-2005 Location: The Mansfield Massive Status: Offline Points: 632 |
Posted: 30-June-2006 at 18:30 | |
Yes Andy that's pretty much it but consider that the
ECU needs more 'instant info' - the air flow meter will always be one step behind the throttle switch. Think of the TPS as giving the ECU some groundwork for the air flow meter to polish off. As a test, take the throttle switch plug off and see how utterly fartless the car is! |
||
AndyS
Really Senior Member II The Last of the Few Joined: 21-August-2003 Location: 55 � North Status: Offline Points: 1365 |
Posted: 30-June-2006 at 11:24 | |
|
||
AndyS
Really Senior Member II The Last of the Few Joined: 21-August-2003 Location: 55 � North Status: Offline Points: 1365 |
Posted: 30-June-2006 at 11:16 | |
|
||
Andy335Touring
Newbie Joined: 26-June-2006 Status: Offline Points: 7 |
Posted: 30-June-2006 at 00:02 | |
Just to expand a little and see if my understanding is correct or not ? 1.) At rest, the tiny microswitch (often referred to as a At tick over the AFM flap is closed(?), the air by-passes the flap, the by-pass area is adjusted by the tick over mixture adjustment screw ? Part throttle, the ECU referances the AFM(air flow),CPS(rpm), IAT and coolant temp sensor and works out the timing and the fueling from the part throttle maps, further adjustments are added on for IAT and coolant temp. Coolant temp needs a bigger adjustment than IAT ? WOT, the AFM flap is pinned open by he force of the air(depending on RPM ?), ECU ignores the AFM and reverts to an RPM based WOT map but will still be affected by IAT and coolant temp corrections ? Of the E30 generation Motronic only the M3 had a baromic sensor which is located inside the ECU casing ??? As i said i'm just kind of testing out my understanding of Motronic management from the E30 era, have i got it right ? |
||
Drew540i
Really Senior Member II Available from all good newsagents! Joined: 15-August-2005 Location: The Mansfield Massive Status: Offline Points: 632 |
Posted: 29-June-2006 at 23:14 | |
Actually it's not the same. M20 and M30 throttle position switches work the other way round from each other and do not interchange.......... |
||
Drew540i
Really Senior Member II Available from all good newsagents! Joined: 15-August-2005 Location: The Mansfield Massive Status: Offline Points: 632 |
Posted: 29-June-2006 at 23:11 | |
And I would suggest you actually know what it is you're talking about. It's amazing how much of a fool you look when you make a glib comment which is oblivious to the facts! A throttle position switch does three things: 1.) At rest, the tiny microswitch (often referred to as a Burgess microswitch after the company that makes it for Bosch) is depressed. This tells the ECU that the engine is at idle. 2.) Just off idle, the microswitch is released which then switches the ECU into part throttle mode, accessing the part throttle maps. 3.) When the throttle switch is fully wound around, two contacts are closed together which sends a signal to the ECU to access the full throttle maps. Maybe you'd care to argue with BMW and Robert Bosch about this? If you like, I can photocopy and send you the relevant pages from the BMW Motronic service information manual? |
||
AndyS
Really Senior Member II The Last of the Few Joined: 21-August-2003 Location: 55 � North Status: Offline Points: 1365 |
Posted: 29-June-2006 at 21:29 | |
Well I suppose in comparison to squeezing an M70 in it isn't too difficult!
|
||
Andy335Touring
Newbie Joined: 26-June-2006 Status: Offline Points: 7 |
Posted: 29-June-2006 at 20:40 | |
I know what you mean mate, the M5 lump would make an excellent swap, though it's a more involved and expensive one to start off with. The extra things over and above the M30 swap is the height of the M5 engine can cause problems so i've read,(custom ?)exhaust manifolds and swapping over to an old brake booster set up to allow enough room for the plenum or smaller servo and chop a small lump out of the plenum. Nothing to difficult though. |
||
Check it out!
Really Senior Member I Joined: 02-May-2004 Location: Bristol/ Glos Status: Offline Points: 373 |
Posted: 29-June-2006 at 16:58 | |
Its the same part as on the e30. a car i know a fair bit about. |
||
www.335itc.co.uk
Its gonna be finished for summer!!! thats the plan!!! |
||
AndyS
Really Senior Member II The Last of the Few Joined: 21-August-2003 Location: 55 � North Status: Offline Points: 1365 |
Posted: 29-June-2006 at 16:55 | |
What's all these TLA's? Thought you said you didn't know much about Sixes? |
||
AndyS
Really Senior Member II The Last of the Few Joined: 21-August-2003 Location: 55 � North Status: Offline Points: 1365 |
Posted: 29-June-2006 at 16:52 | |
Exactly. Why try & reinvent the wheel? |
||
Check it out!
Really Senior Member I Joined: 02-May-2004 Location: Bristol/ Glos Status: Offline Points: 373 |
Posted: 29-June-2006 at 11:51 | |
I would suggest taking the tps (w.o.t) apart and looking. |
||
www.335itc.co.uk
Its gonna be finished for summer!!! thats the plan!!! |
||
Drew540i
Really Senior Member II Available from all good newsagents! Joined: 15-August-2005 Location: The Mansfield Massive Status: Offline Points: 632 |
Posted: 29-June-2006 at 11:42 | |
Yes indeed and therein lies the problem - spend £3000+ building an M30 which might make 300 bhp or spend half that on a 3.6 E34 M5 engine (£1500 is plenty) which is guaranteed 300 bhp, perfect driveability and reasonable(ish) mpg. Remove all the air pump crap, ditch the catalyst and grind out all the air injection stubs from the exhaust manifold. With a chip it should be good for 325 bhp. It also drops straight into where an M30 came from because the blocks are similar. I'm sure even Andy 335 (thanks for the quality info mate!) would have condidered this if he knew how far he'd be going! |
||
Drew540i
Really Senior Member II Available from all good newsagents! Joined: 15-August-2005 Location: The Mansfield Massive Status: Offline Points: 632 |
Posted: 29-June-2006 at 11:34 | |
Nonsense! It also has a full load switch! |
||
AndyS
Really Senior Member II The Last of the Few Joined: 21-August-2003 Location: 55 � North Status: Offline Points: 1365 |
Posted: 28-June-2006 at 14:02 | |
Take a look at what uprating BMW did to the 745 engine to make it last the distance.
There's plenty of info on the E24 forum on Roadfly. You may also want to take a look at the 645 Project. |
||
Check it out!
Really Senior Member I Joined: 02-May-2004 Location: Bristol/ Glos Status: Offline Points: 373 |
Posted: 28-June-2006 at 09:36 | |
Yes, its generally said that you get 35>40% running 5>6psi on a standard engine. Anything more and you start to push yur luck. There is a company that wanted to see how far they could go with a standard engine. I've got to find which site again. But they claim to have bolted a turbo on, and increased the pressure, right up until they had 624 rwhp. this sounds a phenominal amount. This was when the engine decided to pop a piston. Probably find evenrything else was failing around the same point, but didnt critical until then. They do full m30 turbo conversions, but are american. What truth is in their number i really don't know. With the down pipe i think i would have to have a turbo-relocation pipe, as next to the engine looks too tight. the downpipe would then be split to go either side of the steering rack,much like the e30. very tight fit..... Its something i am considering for the future, and will be cheaper than tuning the engine, unlike the 335, where i will doing just that. the 6 should end up a similar straight line speed to the 335 as the turbo should give me more power than all the mods to the 335i. I have seen a few m30's (218bhp) running a cliamed 6>10psi and output between 300 and 365 from a standard lump. although higher figures are no good for drag srips as the standard cluth cooks itself. I have the bmp metal head gasket, and arp bolts. This should be a good days work,but the see the m30's boost handling significantly improved. Again, not until i have done the 335i. On holiday next week, and the next as well. after that i hope to come back with "renewed enthusiasm" to get it finished. |
||
www.335itc.co.uk
Its gonna be finished for summer!!! thats the plan!!! |
||
AndyS
Really Senior Member II The Last of the Few Joined: 21-August-2003 Location: 55 � North Status: Offline Points: 1365 |
Posted: 27-June-2006 at 23:46 | |
Problem with turboing the Six is that steering is in the way. That's why Alpina never did a rhd turbo.
Supercharging is an option & will retain the drivability. Rule of thumb is 30-35% power increase which puts you in the M635 ballpark but with more torque. |
||
Check it out!
Really Senior Member I Joined: 02-May-2004 Location: Bristol/ Glos Status: Offline Points: 373 |
Posted: 27-June-2006 at 17:25 | |
I did speak to jenvey about the socks, and they said the same,in that i would loose power, and an airbox was still the best way to go. Did you weld that yourself? and what kit? i know you weld practically any metal, but alloys, and aluminium etc tend to be much more involved. Love the job on the plenum though, very nice. I'm running a bored out throttle body now (standard bored out) and the respnseis much improved. I havnt noticed it being quicker, it just feels more eager. I would consider it a great "driveability" mod. Not having to pre-load the accelerator when pulling out etc makes the mcar a much better drive. Knit, i agree, and this will be my limiting factor. I know 300 is achievable, it may just be that it idles at 2k, and comes on song 6000>7000 which isnt a nice drive. The low down torque of the m30 is great, so different to what i have been used to (the 2.5 m20). I will take the engine as far as i can, whilst playing a balancing act with "driveability vs power". That tube type manifold. I have that. Its basically the same as the 745i turbo manifold as well. great for adapting for a turbo conversion though! Considering thison the six, as i won't be turboing the 335i, i have the full kit left over....... (tells himself he must get the 335i finished first, or all friends and relatives will crucify him). |
||
www.335itc.co.uk
Its gonna be finished for summer!!! thats the plan!!! |
||
Shem
Groupie Joined: 04-November-2005 Location: Hampshire Status: Offline Points: 51 |
Posted: 27-June-2006 at 17:21 | |
For those who are interested I've just bought a recon BOSCH AFM for an 87 Highline and it was £195+VAT. I did shopped around but I'm fairly new to these cars so may not know all the best places. |
||
What fuel crisis?
|
||
Post Reply | Page 123> |
|
Forum Jump | Forum Permissions You cannot post new topics in this forum You cannot reply to topics in this forum You cannot delete your posts in this forum You cannot edit your posts in this forum You cannot create polls in this forum You cannot vote in polls in this forum |