Geoffrey

Since we are using a speed density system, the idle should be at 900rpm and it will be very smooth like any production car.

The 9M USA basic MoTeC conversion kit is roughly $7900 installed and mapped. Head and cam is extra.

No, this will not pass CA since it doesn't have a CARB number on the kit.

Cupcar#12

hummm......
what do you think the effectivness would be w/o the heads and cams on say a 34K mile car...
(the fact that it is completely reversible is very interesting for obvious reasons)

any detonation detection?

Geoffrey

I can't say because I haven't tested a conversion on a stock engine so I'd have to go by 9M's experience which I believe is about 300hp, but that may be with some exhaust bypassing.

The MoTeC M48 does not have knock detection so the engine is tuned for one single type of fuel. The second of the two 9M cars also has 9M sport pistons which have almost a full 1pt compression advantage over the stock pistons. We'll be tuning that car for 91 octane fuel.

tonytaylor

I would be inyerested in knowing what hp and torque numbers you get from your conversion.

My C2 is running a similar set up to that discribed above. I have the dyno figures from 9M ( you may possibly be aware of them) and would be interested in how they compare to those you acheive.

Not that I think the 9M numbers are wrong. If anything they seem pessimistic given the cars performance compared with other cars on track.

Feel free to pm me offline if you don't want to disclose your results publicaly.

Geoffrey

The car is now running and I'll be tuning it on Saturday. So far, I'm happy with it.

mjshira

totally awesome.

any advantage of doing this on a 993 engine?

psiegel

Fun to hear more and driving impressions

Geoffrey

Similar benefits can be realized on the 993 engine, although the 993 engine has larger intake ports than the 964. The port size on the 993 is not as optimized for the engine as the 964 port. Other than that, the cam towers are much nicer to work with and fairly easy to convert to mechanical rockers. The wiring harness presents some challenges since in the US an 88 pin ECU and connector is used where in Europe a 55 pin ECU connector is used, just like the 964. There is not a conversion box for the 88 pin that I'm aware of. I've done things like purchase an ECU off ebay an cut the connector off of it to make an adapter harness. It really is only a little extra work.

Bill Verburg

US 993 used 55pin harness thru MY95


Are you using wideband O2?

Have you used AC request option?

Have you used aux outmuts for idle control?

What are the aux compensations used for?

Geoffrey

Bill, check that because I think the 95 non varioram engine also uses 88 pin ECU, the same as the varioram engine. Its been awhile so I may be wrong.

Yes, I am using the MoTeC internal wide band O2 processor and Bosch indycar wideband O2 sensor which is also logged in the 512k of logging memory. The MoTeC lambda table is defined for the desired AFR for each cell (880 of them). A narrow band sensor can only compensate to a lambda value of 1 so it is only effective at idle and cruise.

I have used the A/C request option which is also tied into the Idle Air control function, but not on this car which has had its A/C removed.

I am using a PWM Aux output to control the factory 964 idle control valve. The engine idles smoothly at 860rpm with a 290 degree duration camshaft.

Aux compensations? What do you mean?

Bill Verburg

It's for sure that all OBD1 993s, which means through MY 95 are 55pin as are all RoW n/a 993 vrams. That's why it was easy to put my RoW '97 vram 3.8RS into my '95 w/o too many issues. The adapter that you used for the 964s would likely work the same for a '95 993

Just reading thru the M48 manual and spec sheets I see under fuel calibration "Two Auxiliary compensations " and "Cold Start " I recall from our previous discussions that you mentioned a cold start issue and was just wondering ...(always a dangerous thing w/ me)

Geoffrey

MoTeC has a number of different compensations that can be used to alter fuel and ignition timing as well as a good cold start function.

Cold start is programmed for the following:
- initial additional fuel injected when the engine is turned on
- additional fuel when the throttle is pressed beyond 90% (I don't use this)
- additional fuel added based on engine temp
- additional fuel added when the engine is cranking
- additional fuel added after the engine first starts, decaying to 0 over x amount of time (I use 30 seconds)

All of this is added to the amount of fuel already in the main fuel table, so it is very flexible in getting the engine to start quickly and reliably. What I think you were referring to was that I mentioned that an engine with ITBs and no idle air bypass will generally not idle when cold. It takes a few seconds to warm up and idle about 3-500rpm lower than warm high idle.

There is an aux voltage channel and an aux temp channel that can be assigned a sensor and used to compensate the fuel and ignition tables. In this case, the aux volt channel is assigned a barometric pressure sensor to compensate for weather pressure changes and altitude so the engine runs the same AFR regardless of condition. The actual load is the manifold pressure divided by the barometric pressure. I'm not using the aux temp channel which I usually assign oil temp in a 911, but since the factory harness does not have provisions and this is to be a plug-and-play kit, I didn't add it.

Ritter v4.0

Geoffrey- what is a "speed density system"?

Geoffrey

David, an engine management system needs to know 2 basic pieces of information to determine how much fuel or ignition timing the engine requires. One of them is RPM, the other is a representation of engine load or Mass of air entering the engine. There are 4 basic ways to measure engine load:

Air Flow Meter - measures the air flow and may compensate for temperature. Does not measure Mass
Throttle Position - measures throttle position and with air temp compensation calculates load. Does not measure mass
Mass Air Flow - measures air mass directly
Speed Density - uses air temperature and manifold pressure to calculate air mass.

Ritter v4.0

Thanks for the education. Is that a rough ranking (bottom up) in terms of your preference?