Jadz928

Weissach1982,
I sent you a pm regarding custom exhausts.

Jon F

Sorry for the delay in posting an update! My 928 is back together. I put in an air-fuel gauge and as with Mark K's friend's '82, I need to pick up an adjustable rising-rate fuel regulator to deal with the lean mixture. The car feels faster (especially under part throttle), but under heavy acceleration it feels like it is surging (faster-slower-faster-slower, etc). What really concerns me, though, is that the car leans out initially when the gas is pushed down, and then the mixture catches up a few seconds later. I don't understand the mechanics of the L-jet system enough to know if this is a failure of a particular part. On two occasions now, both a redline shift from first to second, the car has sputtered terribly. It was as though the engine just turned off suddenly when I pressed the gas in again after shifting from first to second. Following this event, the car would buck intermittently (and quite violently) for several minutes under part- and full-throttle acceleration, and then the problem would disappear. Something tells me that this is an AFM problem, but if you have any ideas, please speak up!

I drove the car to my parents' house for Thanksgiving (round trip about 850 miles) and about 15 miles from home the final muffler detached from the car. A previous owner had replaced the intermediate muffler with a straight pipe, and it cracked. The muffler is dented slightly and scuffed up a bit from being dragged underneath the car for a quarter of a mile or so. I'm going to post a new topic to see if anyone in SoCal has a cat-back section available from a 16v car, or I'll just get the old one welded back on. Needless to say, the car is EXTREMELY loud with no mufflers and an empty cat.

Because of these problems, I haven't yet dynoed the car. I plan on ordering the fuel regulator next week and doing some tuning which I suppose will take some time to get right. Hopefully I won't need an AFM as well. When I feel comfortable enough with the mixture, I'll dyno it. It's not worth blowing the car up to get some dyno numbers!

Weissach1982

Would these problems happen on all 16V with AFM 928s or is this just on your car? Because I have already ordered my parts and they'll be here soon, i don't wan to put them on if its going to ''F'' up my car, because it runs good now. I just wanted a little more ummphh. Good to hear that it gives you good power under part throttle. Hope your car turns out to run well. Keep me posted with what you do to your car Jon.
Thanks all,
Cory J.
82 Weissach

John Speake

Hi JonF,
Glad to hear you have got the car running again.

I'm not sure what all theissues are that you have, but when I had a L jet Opel Manta, I took the cover off the AFM and lossened the spring tension a couple of notches. This would give a much better pickup as it meant the flap responded quicker, and overshot, giving instant enrichment.

Might be worth a try in combination with a RRFPR.

Best regards,

mark kibort

These problems are not caused by the euro stuff. there could be a vacuum leak or some other issues. the 82 that we did, showed none of these issues, and then again, why would it. all you are doing is opening up the intake. in fact, you can simulate what you had, by making the throttle not open as far!.

Mixture should be instantaneous. make sure your 75% full throttle microswitch is engaging!! this is a common problem.

The AFM is very responsive. remember, i had a 84 part euro 5 liter and anyone that has seen my videos (and heard them) can see, there is no lack of throttle response and mixture. the AFM is instantaneous. the flap is just like a feather in the breeze. in fact, bosch measures pressuer drop across the flap at .08psi. (no restriction do to the flap, now its size is a different story, but not a big looser, as proved by my 292hp rear wheel and 12:3:1 fuel mixture on the dyno)

dont loosen the spring, this will just make the part throttle mixtures to rich . throttle response will not be effected. we played alot with that on a 911AFM and only caused big head aches to get things right again. also a surging problem caused by a computer issue. (ECU)

check fuel pressure, fuel pump, clogged fuel filter, injectors, etc.

again, we installed the euro stuff and it works great. our mixture is slightly leaner than we would want for racing, but its not that bad. (only bad with the eRAM attached. with a new fuel reg, this problem should go away and more hp should be found)

attached is the 911 curve with only a cat back change and a tube intake on a stock AFM and new computer chip. (showing the AFM can make this kind of hp perfectly)

MK

Weissach1982

Sounds good to me then, i'm ready to get my parts in and start porting.
-Mark can porting with air tools make along with the time to put everything on be done ina weekend? Because I would need the car for work and maybe school?
Cory J.

mark kibort

Yes the porting only takes about 30min. you will also need to pull the fitting for the oil filler breather, and remove it, thread it (easy, its soft aluminum) and thread in an elbow.

you can do this in a weekend. not very complicated, just nuts and bolt work

mk

toofast928

Has anyone checked to see if the Euro injectors LH (16v) swap into the USA L system. That is do the Euro injectors flow more fuel? While were swapping the 16v intake, why not do the injectors also. Better alternative than a AFPR.

mark kibort

"Billy, Put the gun down and back away"

Seriously, i thought of this too, as I converted my US 84 to the euro gear. However, thanks to a basic electronics background, I put an ohm meter on the two sets of injectors. BIG BIG dif. basicallly, the euro injectors are very low resistance, higher current. the US injectors have quite a bit more resistance. so, put a euro injector on a US brain, and you will loose a brain!( along with some cash)

the best way is to just get the rising rate fuel regulator. it increases the pressure to more S4 like ranges and higher, as well as the gains of better atomization of the fuel air mixture.. i ran my fuel pressure up to the max of 53psi or so, and had about 290rear wheel hp on my part euro 5 liter with US injection.

Hope that helps.

MK

Weissach1982

Where is the oil filler breather, so I can remove it? Why do you have to thread it?
Thanks,
Cory J.

mark kibort

on the oil filler cap, there is a breather line. this goes to the bottom of the throttle body, attaching to the that would be the " top" of the "U". on the U is hose. this hose cannot be used with the euro throttle body, as it will hit and you will not be able to attach the throttle body to the "u". so, you have to remove it. (its a light press fit) then, if you thread in a short elbow, facing the opening to the heads, you can then attach the hose to it, and then the TB will attach to the U with no issues. also, use an ohm meter to find out what legs of the microswitch on the TB are to be used to replace the microswitches on the stock US throttle body. ignor the idle microswitch, as this is not needed and makes the car stumble when reved quickly. however if you want to use it, the euro microswitch has the idle cut off fuel switch as well.
mk

QUOTE]Originally posted by Weissach1982
Where is the oil filler breather, so I can remove it? Why do you have to thread it?
Thanks,
Cory J. [/QUOTE]

toofast928

Hi Mark,
Write that last part again? How does the microswitch attach to the euro linkage? By reusing the USA brackets or fabricating my own..........

mark kibort

so, you have two choices. ive done it both ways. (my old part euro 5 liter and scots 82) use the old microswitches and make an "L" bracket to attach them to to hit the mechanizm of the Throttle linkage Or, loose the old US stuff, and use the sealed microswitch that comes on the euro throttle body. there are 3 connections. one for 75% full throttle for fuel enrichment, and the idle fuel cut off. I would not use the idle cut off as it makes for a abrupt off throttle engine speed drop, and in racing, gives too much compression braking as well as running the risk of the engine dying in slow turns with high braking pressure.
US bracket is part of the TB and cannot be transfered.

So, I would use the euro micro switch assembly. (but you have to move the oil breather tube for the filler cap)

MK

[/QUOTE]

Weissach1982

-Mark
"its a light press fit) then, if you thread in a short elbow, facing the opening to the heads, you can then attach the hose to it, and then the TB will attach to the U with no issues"

What about another kind of oil breather could I use other than what you said or could would your idea work better because I was a little confused about it.
And about the Microswitch off of the euro parts, do you have to rewire anything for it to mate up to the US electronics?
Thanks,
Cory J.

toofast928

Mark,
By "sealed microswitch that comes on the euro throttle body. there are 3 connections" you mean the throttle position sensor on the throttle shaft? Or is their a Euro miroswitch bracket I'm missing?
Tony--