Bavarian-Board.co.uk - BMW Owners Discussion Forum Homepage
Forum Home Forum Home > Technical & Model Specific Forums > BMW 3 Series
  New Posts New Posts RSS Feed - 325i cab power increase !!
  FAQ FAQ  Forum Search   Register Register  Login Login

Forum Locked325i cab power increase !!
 Post Reply Post Reply Page  <123>
Author
Message
  Topic Search Topic Search  Topic Options Topic Options
b318isp View Drop Down
Moderator Group
Moderator Group
Avatar

Joined: 10-October-2002
Location: Ireland
Status: Offline
Points: 2057 		Direct Link To This Post Posted: 05-November-2004 at 08:25
Originally posted by chippeduk chippeduk wrote:

You can dissagree, thats an opinion and perfect for forums but the fact is, you fit the ported throttle body and you will notice the difference right away, not only top end but throughout the rev range.


Yep, but the problem is that I have never seen fact - only peoples opinion. I'm an engineer, so I need to be otherwise convinced of opinions (by explantion) to change my point of view. There is no logic in what you say given that a throttle plate, an airflow meter flap and a valve (or two!) with its inlet tract are also in the way.

I always wonder why BMW picked specific sizes for a throttle body. Narrower pipework keeps the air flowing faster and there are other possible resonant aspects too. It could be possible that increasing the throttle bocy aperture would reduce power!

My E30 318is Site
Back to Top
Sponsored Links


Back to Top
chippeduk View Drop Down
Really Senior Member II
Really Senior Member II
Avatar
ECU Tech

Joined: 04-June-2004
Location: United Kingdom
Status: Offline
Points: 696 		Direct Link To This Post Posted: 05-November-2004 at 08:32

I can try and help here.

I have a copy of an original alpina ecu code.

The C2 alpina (B3 in germany) was a 2.7 litre M20 powered car produced with 218bhp.

They released this car to the insurance people who give an estimate on insurance rating etc etc and they gave it a high grouping.

They then modded the car to give lower power and changed the mapping too produce 210hp.

I know this is not in relation to the throttle body but it shows of why manufacturers mod cars backwards to aid the selling process.

 

The e30 325i M20 was actually 191hp but was sold as 170hp after being throttled.

The e36 325i M50 was actually 204hp but was sold as 192hp after being throttled.
Back to Top
b318isp View Drop Down
Moderator Group
Moderator Group
Avatar

Joined: 10-October-2002
Location: Ireland
Status: Offline
Points: 2057 		Direct Link To This Post Posted: 05-November-2004 at 10:09
I don't have an argument on chips - I have one in my car and there are improvements as demonstrated on a rolling road!

What is your source re. the M20 with 191bhp? For a 2v/cylinder basic engine, that's 76.4 bhp/litre which I would seriously doubt.

My E30 318is Site
Back to Top
daddy cool View Drop Down
Really Senior Member II
Really Senior Member II


Joined: 27-October-2003
Location: Sussex
Status: Offline
Points: 691 		Direct Link To This Post Posted: 05-November-2004 at 11:25

typical germans ,,,  take a standard car spend thousands on research and development  put a bigger engine in it to get more power  then de tune it to make it slower .........  actually not like the germans at all ???  

i didnty realize the 2.7 conversions released that much bhp , i shoulda just repaired my old one

e30 2.7 cab
e30 325i
e30 325 sport
e30 318 touring
e28 m5
e28 m535
e34 m5
e39 540
e36 318ti (green)
e36 318ti (mauve)
Back to Top
chippeduk View Drop Down
Really Senior Member II
Really Senior Member II
Avatar
ECU Tech

Joined: 04-June-2004
Location: United Kingdom
Status: Offline
Points: 696 		Direct Link To This Post Posted: 05-November-2004 at 14:24
My source is Ahmed Khan (programmer for BMW)
Back to Top
GT6-M3 View Drop Down
Senior Member II
Senior Member II


Joined: 11-August-2004
Location: England
Status: Offline
Points: 237 		Direct Link To This Post Posted: 06-November-2004 at 15:46

I also have yet to see any theory to back up the ported TB claim. If someone could explain to me why it should work, after I've explained why it shouldn't, I'd be much happier about the whole thing.

Also, what do you do to a TB that costs �120?

You can't remove any metal, or the butterfly wouldn't fit so other than getting some polish and rubbing that around the inside, which anyone could do, what's the process?

That probably all sounds a bit harsh, but if your theorys are sound, then there shouldn't be a problem posting them :)
If anyone like old cars with big BMW engines, take a look at www.gt6.org.uk
sign the guestbook, you know it makes sense!
Back to Top
chippeduk View Drop Down
Really Senior Member II
Really Senior Member II
Avatar
ECU Tech

Joined: 04-June-2004
Location: United Kingdom
Status: Offline
Points: 696 		Direct Link To This Post Posted: 07-November-2004 at 07:40

in this case i dont think you fully understand the work of alpina527

the unit is ported quite extensivelly and i think he fits a new butterfly to fit the larger diameter.
Back to Top
Peter Fenwick View Drop Down
Bavarian-Board Contributor
Bavarian-Board Contributor
Avatar

Joined: 27-August-2003
Location: Lost somewhere in time...
Status: Offline
Points: 6484 		Direct Link To This Post Posted: 07-November-2004 at 10:43
Originally posted by chippeduk chippeduk wrote:

in this case i dont think you fully understand the work of alpina527

the unit is ported quite extensivelly and i think he fits a new butterfly to fit the larger diameter.

.....and there are lots of people willing to vouch for the power increases that his throttle body yeilds.

Entering an age of Austerity and now driving a Focus Diesel.
Back to Top
chippeduk View Drop Down
Really Senior Member II
Really Senior Member II
Avatar
ECU Tech

Joined: 04-June-2004
Location: United Kingdom
Status: Offline
Points: 696 		Direct Link To This Post Posted: 07-November-2004 at 10:45
i am yet to here of a single person who has said they dont.
Back to Top
chippeduk View Drop Down
Really Senior Member II
Really Senior Member II
Avatar
ECU Tech

Joined: 04-June-2004
Location: United Kingdom
Status: Offline
Points: 696 		Direct Link To This Post Posted: 07-November-2004 at 10:47

a piccy to view whats done.

 
Back to Top
GT6-M3 View Drop Down
Senior Member II
Senior Member II


Joined: 11-August-2004
Location: England
Status: Offline
Points: 237 		Direct Link To This Post Posted: 07-November-2004 at 17:59

Ooh very nice :)

However, fact of the matter is that untill the TB becomes a restirction in it's own right, i.e. at WOT, you won't see any power increase.

You will however get more power for the same throttle opening, but that's not to be confused with having more power at a given engine speed.

Power isn't made miles away from the engine in the TB. It's made in the cylinder head and is more influenced by the tuned length of the induction system and the shape of the ports than the TB attached to it. However, everyone seems to think that big is best.

Unfortunately, if you did want to fit high lift/overlap cams, you'd probably find it necessary to ditch the plenum intake for individual TBs anyway as you'd find the car a real pig do drive around town without doing so.

Still, each unto their own.



Edited by GT6-M3
If anyone like old cars with big BMW engines, take a look at www.gt6.org.uk
sign the guestbook, you know it makes sense!
Back to Top
chippeduk View Drop Down
Really Senior Member II
Really Senior Member II
Avatar
ECU Tech

Joined: 04-June-2004
Location: United Kingdom
Status: Offline
Points: 696 		Direct Link To This Post Posted: 07-November-2004 at 18:11

Ahh, its all in the wording.

Of course, this wont give you much top end power but when are people really after this on a road car ?

what it does do is open the power band making more power throughout the rev range.
Back to Top
GT6-M3 View Drop Down
Senior Member II
Senior Member II


Joined: 11-August-2004
Location: England
Status: Offline
Points: 237 		Direct Link To This Post Posted: 08-November-2004 at 03:20

No, that's all it'll give you.

The TB's not a restriction untill the engine's going quickly, so a bigger TB will only increase the top end.
If anyone like old cars with big BMW engines, take a look at www.gt6.org.uk
sign the guestbook, you know it makes sense!
Back to Top
chippeduk View Drop Down
Really Senior Member II
Really Senior Member II
Avatar
ECU Tech

Joined: 04-June-2004
Location: United Kingdom
Status: Offline
Points: 696 		Direct Link To This Post Posted: 08-November-2004 at 04:03

thats wrong.

how come a ported head gives a wider power band ?
Back to Top
Peter Fenwick View Drop Down
Bavarian-Board Contributor
Bavarian-Board Contributor
Avatar

Joined: 27-August-2003
Location: Lost somewhere in time...
Status: Offline
Points: 6484 		Direct Link To This Post Posted: 08-November-2004 at 04:21
Originally posted by GT6-M3 GT6-M3 wrote:

Ooh very nice :)

However, fact of the matter is that untill the TB becomes a restirction in it's own right, i.e. at WOT, you won't see any power increase.

The throttle body is used to restrict the power on many engines. The Ford zetec engine for example and the old 16v 150bhp Vauxhall engine. Any engine which sees gains just from fitting individual throttle bodies must have some sort of restricition in the standard throttle body. Alpina527 sells them for the 6cyl 328 and 323 engines (and others) which are restricted by the manifold/throttle body.
Entering an age of Austerity and now driving a Focus Diesel.
Back to Top
b318isp View Drop Down
Moderator Group
Moderator Group
Avatar

Joined: 10-October-2002
Location: Ireland
Status: Offline
Points: 2057 		Direct Link To This Post Posted: 08-November-2004 at 04:38
Originally posted by chippeduk chippeduk wrote:

Ahh, its all in the wording.


Of course, this wont give you much top end power but when are people really after this on a road car ?



If I want to drive quickly, I will use high revs and WOT. If people are "not after this", then why do it at all?

Originally posted by chippeduk chippeduk wrote:

what it does do is open the power band making more power throughout the rev range.



But you have not established that. I second the opinion that it just gives that impression by, at part throttle, allowing more air through for the same pedal position.

My E30 318is Site
Back to Top
b318isp View Drop Down
Moderator Group
Moderator Group
Avatar

Joined: 10-October-2002
Location: Ireland
Status: Offline
Points: 2057 		Direct Link To This Post Posted: 08-November-2004 at 04:41
Originally posted by Peter Fenwick Peter Fenwick wrote:

The throttle body is used to restrict the power on many engines. The Ford zetec engine for example and the old 16v 150bhp Vauxhall engine. Any engine which sees gains just from fitting individual throttle bodies must have some sort of restricition in the standard throttle body. Alpina527 sells them for the 6cyl 328 and 323 engines (and others) which are restricted by the manifold/throttle body.



I cannot comment on other cars, but you do not know if this is or isn't the case on the M20. Fitting individual throttle bodies is a significant change in the the whole physics of the inlet tract. You can't compare individual throttle bodies to this discussion.

My E30 318is Site
Back to Top
chippeduk View Drop Down
Really Senior Member II
Really Senior Member II
Avatar
ECU Tech

Joined: 04-June-2004
Location: United Kingdom
Status: Offline
Points: 696 		Direct Link To This Post Posted: 08-November-2004 at 04:47

its the case on nearly all bmw models of the recent era.

i know for a fact that the m20 and the m50 were hindered directly by the throttle body (and/or) inlet manifold, to lower insurance grouping.
Back to Top
Peter Fenwick View Drop Down
Bavarian-Board Contributor
Bavarian-Board Contributor
Avatar

Joined: 27-August-2003
Location: Lost somewhere in time...
Status: Offline
Points: 6484 		Direct Link To This Post Posted: 08-November-2004 at 06:54

Why doesn't someone try one and see what difference it makes?

That way we would no conclusively either way!
Entering an age of Austerity and now driving a Focus Diesel.
Back to Top
chippeduk View Drop Down
Really Senior Member II
Really Senior Member II
Avatar
ECU Tech

Joined: 04-June-2004
Location: United Kingdom
Status: Offline
Points: 696 		Direct Link To This Post Posted: 08-November-2004 at 07:01

i have done.

fitted one on my own car and it made 6hp (although a little of this can be down to different heat temps etc etc)

they have been fitted to dozens of bmws, you only have to look on www.e36coupe.co.uk forums to see whats thought of them
Back to Top
 Post Reply Post Reply Page  <123>
  Share Topic   

Forum Jump Forum Permissions View Drop Down



This page was generated in 0.141 seconds.