INJECTED 1776 ?

[Mr. Bubblehead]

[Russ Wolfe]

[Mr. Bubblehead]

[Russ Wolfe]

[Mr. Bubblehead]

Well cool, it looks like I have a bunch of stuff to play around with and mess up tomorrow. I'll post what works and what doesn't.
_________________
OGST
Samba Member #4862

[Russ Wolfe]

[Mr. Bubblehead]

[seans67]

[Mr. Bubblehead]

OK, well after dinking around with the timing, fuel pressure, and some MPS adjustments the car runs and drives like a fucking rocket. My question now is how much total advance is too much? I know I've got it set at well over 32º when it gets up to 3000 RPM, but I'm running premium fuel and I'm not hearing any pinging so I don't think that there's any detonation going on. My temp gauge (oil temp, it's all a got) is reading just a hair hotter than it normally does, I just don't want to be burning up any valves or pistons or anything. BTW, I am running a Porsche 914 distributor with vacuum advance & retard (the retard side is capped off though). I don't know if this dizzy is any different than a stock type 3 one.
_________________
OGST
Samba Member #4862

[Tram]

I would back that timing down if I were you. I'm not a big fan of running the timing one iota more advanced than specs. Maybe it's just the VW training, but I had the timing thing bashed into my head. I wouldn't risk it.
As to the distributor, timing curves for BOTH #1 amd #3 are equally important. I remember that the stock distributors on Type 3s had a slight retard for #3. Wolfe would probably know offhand what the spec is- I can't remember. I'd get a stock Type 3 distributor if I were you.
_________________
Немає виправдання для війни! Я з Україною.

[seans67]

What is the advance supposed to be at for a stock 1600 with d-jet, Is it just set at 0deg at idle and that's it?

32deg seems like a lot.
_________________
Sean

'71 Squareback '71 Porsche 914 ‘80 Camper '87 Syncro Weekender 1.8T '87 Wolfsburg Weekender '97 Toyota Land Cruiser ‘03 Audi A6 Quattro 3.0 ‘04 Audi A4 Avant Quattro 1.8T ‘05 Audi A4 Quattro 3.0
‘06 Porsche Cayenne Turbo S

[Mr. Bubblehead]

At idle early FI timing is supposed to be at 0º, later systems were at 7º BTDC I think, but I'm talking about total advance, not timing at idle. Mine's set at around 9º BTDC at idle right now.
_________________
OGST
Samba Member #4862

[Russ Wolfe]

[kenikh]

I love this thread; this gives me hope that I can one day soon replace the DCNFs that replaced the FI on my '71 Fastback. It has a 78mm crank and 88mm pistons, so it's a bit bigger than a 1776. Looks like I should go ahead, take the plunge, buy a complete FI and give it a shot.
Thanks for the courage!
_________________
>Kenik<
- 1971 Fastback Resto Hotrod
- 1969 Porsche 911S

"Now, to put a water-cooled engine in the rear and to have the radiator in the front, that's not very intelligent."
-Ferry Porsche

[Kenaneu]

If you're going with something bigger than 1776, you really should consider getting some 2.0 litre injectors to go along with your FI setup. You should be able to find some porsche 914 2.0 d-jet injectors floating around somewhere.

[kenikh]

Yeah, it's a pretty hot 1.9L. Good idea on the injectors.
_________________
>Kenik<
- 1971 Fastback Resto Hotrod
- 1969 Porsche 911S

"Now, to put a water-cooled engine in the rear and to have the radiator in the front, that's not very intelligent."
-Ferry Porsche

[Kenaneu]

Be sure you really do pay some respect to the talk about cams too... You could be in for a seriously long and frustrating process if you're cam is too big...

[kenikh]

Engle 110; I've been told it's possbile. I'm crossing my fingers.
_________________
>Kenik<
- 1971 Fastback Resto Hotrod
- 1969 Porsche 911S

"Now, to put a water-cooled engine in the rear and to have the radiator in the front, that's not very intelligent."
-Ferry Porsche

[kenikh]

I've been thinking more about this issue and am beginning to wonder if an "off the shelf" cam is even the right way to go to improve the performance of EFI on non-stock motors. Since Jetronic uses the intake pulse as the fueling trigger, it seems obvious that a cam with a large degree of overlap and thus greater intake side reversion, is going to make it tough going getting the FI to work correctly. Since it is this reversion that is muddying the intake signal, mitigating this effect seems like it would be design criterion number one in building a good big-bore FI motor.

So the question is, perhaps a custom cam is the solution, especially for these larger motors. Off the shelf cams seem to have been designed from day one with carburetion in mind, with no design consderations set aside for taking into account intake side reversion characteristics. A custom grind cam with minimal overlap, but higher lift to improve cylinder filling for the larger displacement could make performance on big motors better than a stock cam and would minimize reversion downside, as well.

I think it would take some serious calculation to decide how much overlap you can design into the cam, but I'd bet starting with the Engle 110 (which was proven to work with some problems by Mr . Bubblehead) and working back toward stock might be a good way to go.

Thoughts?

BTW, here's a great Camshaft design FAQ
_________________
>Kenik<
- 1971 Fastback Resto Hotrod
- 1969 Porsche 911S

"Now, to put a water-cooled engine in the rear and to have the radiator in the front, that's not very intelligent."
-Ferry Porsche

[Kenaneu]