AFR tuning
 

Question to tuning experts on these engines
were are the good AFR numbers, euro 964 turbo, stock turbo, compression and ignition, other cams, rings between head and cylinders, and ARP studs


i do all tuning on street so wonder what experience you guys have
what AFR gives the best happy engine on the way to boost on this engine type AFR 13,6?

and best performance on boost at max torque up to 5000rpm AFR 11.5?

and Hi rpm 5500 up to 6500 is AFR 12,2 enough to be safe even on track use?



now have 1,3 boost up to 5000rpm then lowering to 0,9 at 6500rpm because i cant get more fuel out of the frankencis

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Wow, 1.3bar? Nice!

I just popped in a new spring to bring my wastegate to 1.0 bar and it definitely makes a difference not only in top end, but it feels like boost onset is quicker too.

I can't help you with street tuning as I've used a dyno. However, I plan on doing some runs at the local uncontrolled airport. I checked with the airport manager first, and will be on freq with a handheld and announcing myself as "back taxiing". More info when that happens.

Beatiful 965!
My targets:
13.0-13.5 idle
14.5 cruise
11.0-11.5 threshold
12.2 redline 1.0bar boost (street) 11.8 (track)
IMO 1.0bar boost is max for a stock long block running on street gas. Let the cam, heads, headers, turbo and exhaust system produce the power.
Electronic WUR is not the limiting factor for fuel delivery, that is job of the fuel distributor.

I forgot to say i also have ported heads 😃

I was i big difference in performance from 1.0 to 1.3 bar
So I think I keep that for street use and lower little for trackdays
Does anyone know the performance limits for euro stock 965 turbo

RarlyL8 I wrote in bad way of course it is not frankencis that is the limit but i can’t get more out of the fuel system with the help of a adjustable WUR and frankencis http://forums.pelicanparts.com/uploa...1601580928.jpg
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FrankenCIS helps if you're doing the eWUR and Lambda as it essentially lets you control control pressure on the fly as well as the fuel delivery. But ultimately the fuel head itself, followed by injector lines are the big limiters.

That's cold start territory.
What's the advantage of being so rich?
The factory spec is 13.9 - 14.1 (CO of 3%).

Every engine has it's sweet spot for idle AFR. Modified engines with SC or more aggressive cams seem to like the lower end of the range while stockish engines like the upper end. Setting leaner (no Lamda) tends to cause lean surging and a rougher idle. Some of that might be contributed to aging components making adjustments less precise.

What is the lower limit of CP?
I see 2.2-2.3 bar in my log at WOT

You can drop it down into the 1's however the stock fuel distributor still may not be able to supply the flow needed.

Okey i toughts i heard that at some point i changeover and gives less fuel again.

Something new happened today
Was on my way to first trackday, but feel small hesitations at light throttle,
So I took a logg file and suddenly the everything is little more leen than before ,
and at 5000 and higher super leen AFR 13.6!
What could possible happened?
I checked both fuel pumps is running
Systempressure 6,9Bar idle. 6.1bar at WOT ( I did not have sensor before so can’t check old logg if it is correct
But my controlpressure looks to be about the same as before when it was running good at afr 12.2

Anyone have good ideas were my fuel disappear?
So frustrating not to be able to race on the track

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Check your intake manifold nut torque. Those plastic spaces between the cylinder head and manifold seem to warp, crack, expand and contrast and result in air leaks. I recently just went through this; in fact I abandoned the plastic ones and went with milled aluminum ones from TurnoKraft.

Agree plastic injector blocks no good. But airleaks under boost = richer. Suspect lack of fuel somewhere. At 1 bar I am happy to run 12.5 AFR at top end rpm. Has gone leaner, no damage, but why would you? Stay within 12.5 and should be fine as long as timing OK.
Dropping the CP below a certain level makes no difference. Your FD is already at max at that point. That will depend on engine and fuel requirements. But for mine, below around 2.5 gives no more fuel. Already flowing as much as system will produce. Mine idles best around 12.5. All different - depending on mods and age of engine wear. Fresher engine - leaner target. Same engine with more wear = richer target. The engine will tell you where that spot is. Awesome machine you have. Good luck and don't break it.
Alan

System pressure should be independent of anything the engine is doing in order to adequately feed the injectors at redline full boost. System capacity is reached when all of the fuel exits the injectors and none returns to the tank. I'd replace the fuel filter and go from there.

Is there some port or fitting that allows you to measure system pressure under operating conditions? My CIS pressure tester has a ball valve on it and plumbs in line with the WUR; with the valve open the WUR control pressure is observable, with it closed its reading system pressure.
But you guys both seem to be referring to another way to measure SP while underway.

BTW, gorgeous car.

AFAIK you have to shut the fuel off to the WUR to get SP. Can't see another way to do it. You would think there should be. The problem is the SP is controlled internally by the relief spring in the FD. You can't break in to that system - as far as I can figure.
Alan

If you break in to the line in to the FD you should get that result. messy but probably do-able.
Alan

I echo what Ken is saying.

I have read many CIS posts on the forum and many refer to system pressure, control pressure, etc but I haven’t seen a clear reference on how/where to measure each.

For example:
System pressure is measured inline between the fuel filter and the FD, uses x fittings
Control pressure is measured between the FD and the WUR and uses y fittings

I have been searching for the above quite some time, and suspect that several CIS threads have had folks mixing them up.

Just to clarify I don’t know if what I posted is correct.