whalebird

The early 911 Mechanical injection had a barometer for enrichment located right in the engine compartment...and carbs too.

scarceller

I think getting a 0-5v automotive barometer is the way to go. I plan to locate one of these simple devices and simply record the results.

Was wondering if anyone had already done this.

Thanks for all the replies.

Amber Gramps

Something like this sounds awesome. ....and I gotta say you rock.

http://yhst-21371435622982.stores.ya...baro11001.html


Something tells me you've been here before:

http://www.gcdataconcepts.com/carairflow.html

scarceller

I plan to get a simple MAP sensor (maybe Ford type) then place sensor in the passenger cabin and run small hose to engine compartment. This will allow the sensor to reference the cabin air and compare the difference to engine bay pressure. I'll log the data using my logger.

Thoughts?

whalebird

Can you put the stock AFM back on the car for a comparison? Mass-flow meters are considered by many to be worthless on these such motors.
As for flow, one of our fellow listers has a 84 carrera with a 3.4 that pull strong right thru the redline as per his dyno posts. Stock injection, twin ignition, adequate exhaust and a SW chip, he's hovering around 265HP IIRC. Your not going to get that much out of a euro 3.2.
I've experienced similar engines with both CIS and Motronic injection and they can take your breath with surprising flexibility and remarkable throttle responce...basically stock. I suspect CIS injection and motronic will both support motors approaching 300HP, with cam grind being a major limit.
If your Pistons/cams are all compatible with your injection, you should be able to easily reach max output with stock injection.

rusnak

In "Porsche 911 Engine History and Development" author Tobias Aichelle notes that the 3.2 intake was designed to compress air above 4k rpm. I suspect this is not infinite, as cam timing would eventually hit the wall. Also, the 3.2 had the highest specific output of any non-turbo street Porsche, or any street engine, on the road at that time.

whalebird

A euro 3.2 with SSI and webcam 20/21 should be a swell running motor. Outside of a stand alone injection like mega-squirt, tuning is futile. Even then your spending lots of resources chasing a few HP.

scarceller

This motor pulls strong, it dynoed at 223 RWH (256HP estimate at crank 15% drive train loss) with 201FP but drops very quickly in torque and HP after 5800 RPMs and this is what I'm questioning.

I agree that many MAF conversions are not worth it, but this is because many simply try to make the MAF mimic a AFM. My system does not do this. I re-wrote all the software in the motronic to propery deal with the very responsive MAF signal. The entire air to fuel model is completely re-written. The MAF has helped tons with throttle response and general driveabilty. It also tends to keep AFRs very rock solid at all loads and RPMs, I never run closed loop. I have yet to re-dyno the engine at WOT with the new MAF since I'm still fine tuning part throttle loads. But I agree it most likely won't make much more HP than with the tuned AFM setup.

The new system no longer has fuel trim tables it now has true AFR tables. You simply set the target AFR in a Fuel table and that's the AFR you get on the WBO2. I also have true injector modeling tables that allow me to drop in any size injector from 24lb to 30+ lb injectors. I can run low or hi imp injectors with now issues. The real goal of the project is a true MAF setup that allows real tune-ability. The idea was to build a system that gives great tunabilty with the stock DME, I see no reason to ever go to a stand alone system for these engines. Sure true sequential injection would help idle and PT loads but not by much and at WOT the system I developed will do just as well as any EFI system available. The MAF gives me solid air to fuel model that does not vary with altitude or air temps.

Also, because I wrote all the code I even have the car currently running very well with a BMW 059 DME and Ford 0280155715 4 hole modern day hi-imp injectors and the car runs perfectly!

Also, the AFM behaves the same exact way above 5600RPMs Air Flow starts to drop off. I'm just chasing down possible reasons for this, could be it is what it is and I'm OK with that as the car runs very strong with solid torque from 3800RPMs right up through 5800RPMs.

wwest

Valve float..?

Steve Weiner-Rennsport Systems

Not at 5800 RPM unless there are some broken valve springs,...

RollingArt

My guess would be the valve timing is hitting a wall.

What your motor needs nest is variable valve timing to correct overlap for high rpm operation. Without VVT the cams can only be optimized to a certain RPM range. GL overcoming that obstacle.

Very interesting project by the way. Would like to hear more about it.




Phil

whalebird

5800 RPMs is nothing to the stock valvetrain. Cam timing IS a variable here.

RollingArt

Ahh, variable yes, but I'm talking about dynamically variable, as in changing while motor is running, like my 997 or bmw vanos, or any number of other new engine designs.

If I interpreted your post right you're talking about initial set-up of the 3.2 motor cams being a variable. No?




Phil

wwest

My '78 Targa has 2 springs/valve, inner one fails and you don't notice except....

whalebird

Yes, and final set up. Multi stage cams and manifolds are certainly in vogue for a lot of reasons. When it comes to the older cars, I like a nice gentle arc to the torque curve. Relativly early in the 911 evolution, the same basic architecture as a 3.2 was turning 8000. Stock 911 rocker arms are good for 8000 I've been told.
I'm not sure the OP is seeing much improvement in his efforts over a stock (euro) 3.2. I suspect something is basically wrong.