engine and drivetrain kitty, kitty, kitty, at what point is a/f mix too lean?

[Guest Anonymous]

(nt)

[Guest Anonymous]

URL: http://www.bmw2002faq.com/store/index.html

pump first, then add cam to get max avail power... next step would be head work (good time to do it is when changing the cam, actually)

-Rob

[Guest Anonymous]

cam and motor mods, then pump, then the M3 conversion.

Seriously, if you do the pump first, you just have to adjust it again when you do the cam. Make the motor how you want, then get the pump straightened out.

[Guest Anonymous]

(nt)

[Guest Anonymous]

want to examine it. It still needs to flow more fuel for my motor. I too have a very lean spot at steady throttle, (P2 or P3) at any RPM range.

[Guest Anonymous]

with standard pump adjusted 1 1/2 turns, linkage set up by

the book with idle pos. = to close throtle and full stop

matching WOT (standard everything else)

RPM(k) a/f ratio

2.5 ---- 13.5

3.0 ---- 15.8

3.5 ---- 16

4.0 ---- 15.8

4.5 ---- 16

5.0 ---- 15.5

5.5 ---- 14.8

6.0 ---- 14.2

6.5 ---- 12.1

7 .0 ---- 11.2

this feels pretty strong, and I could live with it, but hell I have

another pump, I am going for it! Honey: " I have some work to

do at the shop, can we do the gardening some other day?"

[Guest Anonymous]

The deliver of fuel with a stock pump is completely wrong. You cannot change the curve, you can only shift it.

Best way is with a new cone, or IMO better yet a custom adjustable linkage to tailor the WOT delivery.

[Guest Anonymous]

firstly the following is a copy of an old post from roadfly regarding use

of "special cams" in a4 motors. This was supposedly obtained directly

from alpina via Lars- as you can read in the following text. I tend to

believe this although one never knows:

Message Title: Some comments from Germany!

Posted by: Lars Guenther on 2002-11-27 at 07:41:33

(posted from: Host: nafp2-148.rz.uni-frankfurt.de IP: 141.2.23.148)

Message:

First of all: Never seen a 02 with center throttled standard tii Kugl

setup with more than 150 hp. Don`t like to say you are

lying therefor it might be possible - but if it is, tell me how!

Dynos that you drive on with the complete car can only measure rear

wheel power. With some calculating you can get away

the "turnagainst" (sorry I`m german and my english gets to its borders

with describing these highly technical things)

powers of the dyno and the car itself (wheels, tranny, drivetrain etc.).

Depending on how you do the calculating the engine

power that follows out of it can differ quite a lot. As said above the

numbers are the thing to count. If dyno owner gets

out bad hp numbers customer might not come back. Friend of mine

was long year engineer at Volkswagen research in Wolfsburg

and long year touring car race driver - he is 02 fan although having

worked at VW / still has some 02s. According to his

experience calculated custom dyno powers are about 10% too high.

Alpina A4 heads mostly do have 47/39 valves. Special versions even

bigger (changed valve angle and so on).

Alpina always used special checked heads from daily BMW factory

production. Depending on year of make you will find 121,

E12 and E21 among them.

121 and E12 heads do differ in combustion room style

(Zweikugelwirbelwanne against Dreikugelwirbelwanne) and combustion

ratio. Change was made because of changed emission regulations in

Germany (and US, of course but US engines had some more

modifications, too). Other there was a problem with early plastic tube

121 head tii`s with higher compression: Engines

sometimes had ÷lschaumbildung (don`t know that in english) and

cracked. Same problems with some versions of the big sixes

from that years (don`t know if that models were delivered to US). Stock

121 heads do have 44mm inlet valves, stock E12 have

46mm.

3D Kugl cam has not been changed for A4 engines and does not have

to be changed for cams up to 304 Schrick. This is a direct

Alpina information - discussed that thing for about three hours with

Mr Kerner (head of engine check) and Mr Woitsch (head

of cylinder head division). Both at Alpina for 30 years and therefor

well-informed about the old times. Fuel supply is

enough!

Late A4 engines also came with 306 Alpina cam - cannot be seen from

the outside because they didn`t change the signing.

Was because of some cars having bad idle with E21 head. No obvious

diferences in outcoming hp. No changes to Kugl, too.

Special edition A4/S with 316, 320, 324 or even other cams had

changed pumps.

Race cars with slide throttle had special 2D cams and sometimes

bigger pressure valves at the Kugl pump (similar to the

16V engines Formula 2 M12B or Schnitzer - diameter up to 8,5mm

against stock 6mm / not really sure about the concrete

numbers, but can look it up if someone is interested).

Very hard to get more than real 200hp out of 8V M10 engine. Not

possible with normal street tuning.

Regards, Lars.

Ok- so if that is true then the alpina pumps may have simply been

adjusted without changes to the cam. Additionally I see no reason that

one cannot tune for a perfect WOT run. While the fuel curve is difficult

to change the air curve is not. It is simply a matter of getting the

throttle plates set correctly to the fuel that is coming out of the engine.

In a stock throttle body this could be done bu modifying the half moon

cam as needed. With the A4 this could be accomplished in a similar

fashion. Thus the air curve is corrected to the fuel as apposed to

adjusting the fuel. No telling what this would do to the mix at a

different throttle position.

At any rate my hunch is that this is not necessary. If Lars' info is correct

then it is a matter of adjusting the pump to get it cued up.

[Guest Anonymous]

there is another way to adjust the air/fuel mixture on the A4.

It is going to be hard to explain, but I will give it a try:

Focus on the crank that connects and translate the x

movement of the pump to the y movement on the throtle.

The y starts at 4 o'clock (or 135 degrees), the initial angular

position of the x arm can determine the initial rate of angular

change for any given x. So the largest pump movement

without much throtle movement is achived at either side of

the bottom of the crank, so I can improve my lean area by

shifting the x linkage to swing around the bottom during 3-5 k

rpm. It is just another adjustment if one can fabricate such a

crank...

[Guest Anonymous]

But it is the second A4 I've had (the one on Jay's Inka 72 is the first) and I've been around a few others since the early 80s and everything I've heard is that Alpina had special 3D cams/different pumps than stock. Who knows what to believe. There were different cams, for instance a different one for the factory turbo. But, what is truth, what is folklore, who knows? I sure don't.

[Guest Anonymous]

Indeed who knows. I bet there were many different setups over the

years.

[Guest Anonymous]

Guys, everyone seems to be focusing on the throttle movement to pump lever arm movement. There is another, much more involved, item that could require changing to match a pump to the engine. The spring that sets the amount of rotation the 3d cam makes as the RPMs change. This is an integral part of the fuel curve from what i have seen by looking at a spare pump that was taken apart.

[Guest Anonymous]

for lots of years. To add to the debate, the pump that is in my car, originally sourced/bought from Josh by the co-builder of the car, was reworked by Ray Korman, by a subsequent owner in the mid 90's to match a Schrick 292 in an E12 MM worked head, that sat on a Metric Mechanic 2.2L bottom. My A4 injection was put on the new MM 2.2L long block ,as is, with a newly developed 300 MM cam. I need to rent dyno time for Billy to dial-in the injection. He is one of the talented few who knows how to tune an A4.He has yet to teach me - but he promised me he would soon. I will dyno the car and rent a big block of time sometime this summer for him to work his black art. As to chassis vs. engine dyno: engine dyno is optimal, of course, but that requires engine tuner/builder to have injection as well as the engine. I knew my builder did not have that machine- his numbers are from chassis dyno tests with "known" car/engine comparisons, and from road testing. Certainly not state of the art stuff- but that costs mountains of money. Not worth it unless the engine is going to be competing and bringing home prizes/money. I am encouraged that the pump has lots of room for adjustment, i am dissapointed that with the 245 5 speed and the 3.90 combo, I need more power from 3rd gear on the track. I am certain the engine has lots more to give. Looking forward to using the untapped power. I do not think the current settings are optimally matched to the "skunk works" MM cam. I cannot get the cam's details, profile, any proprietary info from MM after repeated requests. That irritates me. Jim keeps saying he will send something. I suggested a redacted sheet to be sent to me. Website info and updates are glacially slow at that shop. But the car is fun as it is right now.

[Guest Anonymous]

Supposing one removes the warm up reg and rear cover.....

[Guest Anonymous]

I would be hella careful doing this.

The spring is a flat 'coiled' spring wrapped around a disc attached to one end of the 3d cam (think of a clock winding mechanism).

There is a preload of tension placed on the spring. One end of the flat coil spring is attached to the disc, the other end is attached to the pump. Loosening the end attached to the pump would free the spring to change the preload. If you loosened the pump end of the spring while not holding the spring, the coil will rotate loose and you will be up sh*t creek without a reference to where it was (my belief at least).

BEWARE!!!!!!! - I would not do it without a spare good pump in case something goes wrong (like loosening and the spring unwinds). Hell I would not do it unless you were really after learning about the changes and not so worried about if it ever worked. I think this is a very risky proposition. The only thing I can say in support of trying it is that it is 'the way' to move the fuel delivery curve up or down the rpm scale.

If you attempt this I would hope you make very accurate notes of where the spring is when you start and make small steps to see how the curve shifts. A guess would be loosening the spring tension would shift the fuel curve into the higher rpms.