Anyone out there that may be able to re program our 84NA DME? Its for our race car, we just want to move the rev limiter up to 7K.

Anyone do this kinda thing?

Take Care!

 

Hey John, I would bet Danno could do that for you

 

Maybe this guy would for $$

<a href="http://944dme.tripod.com/of.htm" target="_blank">http://944dme.tripod.com/of.htm</a>

 

David,

I'll leave a message for Danno, funny, with he and I working on so much together, I never thought about him being able to program an early dme...but your right....He gets first shot, maybe its worth a sticker on the car?

THanks Zehnd, But I'll do the Danno route first, if he can't do it, then I'll look up your link.

Take Care!

 

John,
I have asked Danno about a chip for race gas for my 944 Spec racer and have not gotten a reply maybe you have some more pull : )FYI, the previous mentioned <a href="http://tripod???" target="_blank">http://tripod???</a> chip made 2WHP only after correcting a/f.
Paul

 

 

HI John,

I got your message. I'll be sending you a chip to test with a socket to solder into your DME. There are some issues that needs to be addressed:

<ol type="1">[*]the partial-throttle fuel&ignition maps only go up to 6240rpm[*]the full-throttle fuel&ignition maps only go up to 6480rpm[*]I can program in a 7000rpm redline, but will have to richen up the last fuel-zone at 6480rpm by 9% to ensure adequate fuel at 7000rpm[*]even then, the VAF-VolumeAirFlow conversion table (AirFlowVoltage X RPM = InjectorDutyCycle) will have to be scaled for a 3.1L engine. Using a 2.5L table will have you hitting the edge of the maps at only 80% load (3.1L engine flows 24% more air than 2.5/L)... not sure how to get around this yet..[*]the rest-of-world Australian fuel-map looks like the best one to use on your 3.1L car with the most range, but can only be selected with a impedance adaptor where the US cars have the altitude sensor[/list=a]

So on your chips I'll just move that map into the California location. If you can get me a dyno-sheet of your car with air-fuel ratio curve, I can flatten that out for you while we're at it. Then you can scale the entire thing up and down with fuel-pressure.

" the previous mentioned chip made 2WHP only after correcting a/f."

Yeah, if the stock fuel delivery is close to ideal, you're not going to get much more by fine-tuning it. This is probably the case with NA cars since you're not going to be changing the air-flow patterns much from stock.

We can give you fuel-selections to quickly adjust the car for temperature & altitude variations if you want:[*] stock[*] +1% richer[*] +2% richer[*] +3% richer

The real secret lies in the ignition, so your chips will have four possible ignition settings:[*] stock ignition map[*] +1 degree ignition advance[*] +2 degree ignition advance[*] +3 degree ignition advance

These jumps may be too large for your 13.5:1 compression engine, so I can make them as small as 0.36-degrees steps if you like. Want to try out our Knock-Link display to see how close you can push things to the ragged edge?

 

Danno,

You bring up a lot of great points, first off, let me tell you what I would like to do...in a perfect world.

Well, to start off, let me say we dynoed the car for tuning just before the last race. The fuel curve came in a little lean between the 3k an 4krpm area, it was about 14:1 at that area, and just at 13:1 to 6Krpm, we tweaked a little on the regulator and got the curve to read 13:1 all the way to 5500rpm, then it was just a tad rich at 12.5:1. I'd like to see 13:1 all the way accross, but being this close is not more than a couple hp off perfect anyway. I do know that an NA car can lose or gain quite a bit of HP, in just tuning the fuel, for instance, our first session, we were using turbo injectors with the stock rail and reg. we were 20hp down from our estimated Hp rating, our mixture was a thin 15:1. Adding the regulator, we bumped the pressure a tad, and gained 20hp from that alone.

Now, back to what my plans are, maybe you have an idea.

First I want to retard cam timing about 4-5degrees, give the car a pull, adjust the fuel, and see what the gains are if any. If its better then I will set the cam and run it.
From that point, my next step is a ram air, from the hood thru a duct, into the airbox. I will need to simulate this on the dyno some how...need BIG FANS. after all is done, then I need to get the chips burned. I don't know if I want to mess with the timing, other than maybe taking a little out, but I doubt I could advance it much with out melting down. I'm running around 110 octane as it is.

So, to you and anyone else on this list, any ideas???

Take Care

 

[quote]Originally posted by Danno:
<strong>Yeah, if the stock fuel delivery is close to ideal, you're not going to get much more by fine-tuning it. This is probably the case with NA cars since you're not going to be changing the air-flow patterns much from stock.
</strong><hr></blockquote>

Just doing a little monkey guessing here but....

Wouldn't you think that's because the stock maps are a little rich and things that improve VE such as intake, header, exhaust will lean out the mixture some and thus improve power output?

I suspect this is one of the reasons most remapped NA chip don't add much power.

[quote]Originally posted by Danno:
<strong>The real secret lies in the ignition, so your chips will have four possible ignition settings:[*] stock ignition map[*] +1 degree ignition advance[*] +2 degree ignition advance[*] +3 degree ignition advance

These jumps may be too large for your 13.5:1 compression engine, so I can make them as small as 0.36-degrees steps if you like. Want to try out our Knock-Link display to see how close you can push things to the ragged edge?</strong><hr></blockquote>

Isn't it possible to change the timing in different parts of the maps? I know in my 11:1 NA engine for my SE-R they had to pull 3-4 degrees out of the mid-range part throttle maps due to pinging, much the rest of maps were more agressive.

How about finding someone with a 944 Cup or 944 Spec car with the intake, exhaust, header, and use your Knock-Link to come up with some great maps for these cars on race gas. There is a good untapped market there.

 

Isn't the type of gas to be used a critical issue in tuning the thing, especially as far as timing is concerned. John, I didn't see you mention what type of gas you were using on this thing.

 

Danno, if using your Knock sensor, would there be any need for an a/f guage??? As the only purpose of the guage is to make sure it's not leaning out. True, being real rich is a concern, but in regards to turbo application, we just need to know how much more boost to add before det., set it and leave it, then jsut add more octane if running temporay more boost, i.e. track events.

 

Well, not really because knock-detection is really to tune ignition. And O2-sensor ratio readout is to tune the fuel. These are two completely independent settings that work together to give you optimum power from any particular configuration. They SHOULD NOT be used to make up for deficiencies of the other; i.e. extra fuel to make up for improper ignition advance, or retarding spark to make up for insufficient fuel.

The first step in tuning is to get the air-fuel dialed in optimally:



As you can see, the highest pressure in the combustion-chamber is achieved at 12.5:1. Although a range from 12.0-13.0:1 should be close enough with the lean end being more detonation-prone.

Once you get the fuel down, you can then start advancing the ignition up to the point of knocking, then back off a little bit. And optimal ignition is far from easy. Just because you are on the edge of detonation at one particular operating zone, doesn't mean you can't squeeze more out from somewhere else. Similar to how you must have 3D fuel-mapping capability (tuning for flow and load), you need to be able to do the same with ignition. Here are some ignition maps we've been working with...



As you can see, all of these maps are within about 4% of each in terms of minimum and maximum ignition advance values. But they offer vastly different performance and driveability. These are from the worst and the best chips we've examined. Gone are the days where you can simply rotate the distributor in its mount to get a little ignition advance and a little more power... heh, heh...

"Wouldn't you think that's because the stock maps are a little rich and things that improve VE such as intake, header, exhaust will lean out the mixture some and thus improve power output?"

Yeah, forgot that there's still a lot you can do to an NA car. Typically the way to cram more air through the engine is to make all the holes larger and rev the **** out of it.

 

[quote]Originally posted by Danno:
<strong>Yeah, forgot that there's still a lot you can do to an NA car. Typically the way to cram more air through the engine is to make all the holes larger and rev the **** out of it. </strong><hr></blockquote>

True. But, you can also make it breath better. Better scavanging (header) helps. I've yet to see anything to really improve the intake side on an NA 944 yet though. Once I get to the engine on my race car, I plan to fabricate a nice cold air intake with a K&N in the fender well. The hole and grommet are already there. All that is needed is a decent adapter (all the ones I've seen are lame) that has smooth transition from the tube connector to the rectangular openning of the AFM (cut down on turbulence at this critical junction).

Anyway, as I said, there are a number of us who are interested in a good remapped chip for racing optimized for race gas, header, and intake. There's a decent market out there if you can put the maps together.

Also, is it technically possible to extend the maps in the DME?

 

[quote]Originally posted by Geo:
<strong>

True. But, you can also make it breath better. Better scavanging (header) helps. I've yet to see anything to really improve the intake side on an NA 944 yet though. Once I get to the engine on my race car, I plan to fabricate a nice cold air intake with a K&N in the fender well. The hole and grommet are already there. All that is needed is a decent adapter (all the ones I've seen are lame) that has smooth transition from the tube connector to the rectangular openning of the AFM (cut down on turbulence at this critical junction).

</strong><hr></blockquote>

There is a Porsche tech bulliten where the filter intake is cut off and the hole in the fender plugged because of water ingestion. Tends to bend and break rods. There's even a part number for the plastic plug.

Keep the new filter inside and to the top of the engine compartment.

 

[quote]Originally posted by SoCal Driver:
<strong>There is a Porsche tech bulliten where the filter intake is cut off and the hole in the fender plugged because of water ingestion. Tends to bend and break rods. There's even a part number for the plastic plug.

Keep the new filter inside and to the top of the engine compartment.</strong><hr></blockquote>

No thanks.

I'm familiar with the hydrolock issues of running a cold air intake. I fully plan to make my system easy to convert to underhood filter in the event of a rain race (don't need the extra power anyway). There is usually decent power gains to be had from properly designed CAI (typically 6-12 hp).