Greeting from Indianapolis

gwolf · Newly Aquired Joined: 12 Aug 2008 Posts: 4

Have a headscratcher for your contemplation:

Duratec (Lincoln LS) 3.0 DOHC v, 8:1 forgings, turbocharged (7 lbs and creeping up slowly) and intercooled, 42 lb injectors. 8.5 UAP, -.375 IOT, running AFRs of 13-14 in the meaty part of the fuel map, idle at approx 50 Kpa, 900 rpm, 1.4 ms pulsewidth (a little rich, but not eye-watering)

Here is the problem. This engine has a pent-roof combustion chamber, which should require less advance than any other design. When I read about other guys with similar combustion chambers running these levels of boost, they are all in the 10-20 degree range at idle and under boost. I am currently running 30 degrees at idel and 35 degrees under boost, across the map. I cannot get a single ping using 89 octane gas and doing WOT pulls from 1500 rpm in 4th gear. In fact, I can add another 10 degrees of advance at idle before the idle gets hinky.

I am afraid to add any more advance in the load section of the map.

Yes, I have checked the timing sensor to make sure it is on the correct tooth.

Any sage advice is welcomed

jimm · Posted: Wed Aug 13, 2008 5:39 pm Post subject:

Sorry, not sage advice, but I too was surprised at how much advance I could put in the car. Mind you mine is normally aspirated and essentially stock 4 cylinder DOHC engine. The base map started at 14 degrees and 24 at full load with forays into 35 and 36 in the middle zone, but I've since bumped the whole works up 20 degrees and have yet to hear a ping! I'm not sure where the limit is, I really need a load dyno, I'm probably running a bit on the rich side of things and it's 94 octane pump gas.

C. Ludwig · Posted: Thu Aug 14, 2008 12:52 pm Post subject:

First I need to see this Lincoln. I've got a 2000 3.0 manual and have had turbocharging it in the back of my mind for years now. Car to post or send me pics? I live in Louisville so I'm not that far away if you wouldn't mind showing the car off if I'm in your area sometime?

More on point, I'm not sure what the advance curve is with the stock ECU but I can get serious knock when running 89 octane (Ford calls for 91+) and lugging the engine. So with boost, just as you are expecting knock with your settings, I would expect it to knock as well. Have you verified that the timing is accurate? What you're programming you are actually getting?

gwolf · Newly Aquired Joined: 12 Aug 2008 Posts: 4

Jimm,

So you are running 55 degrees at some points on the map? What hind of engine are we talking about? Compression ratio?

gwolf · Newly Aquired Joined: 12 Aug 2008 Posts: 4

Ludwig,

The engine isn't in an LS, it is wedged into a 74 triumph TR6. Installing the turbo wasn't all that difficult: just a matter of plumbing, but since the TR engine bay is almost a foot narrower than the LS, it was a tight fit. The big problem, as always, it getting an engine management system. I use an electromotive Tec2, which works pretty well, but it took me a long time to learn the software.

As you know, the stock engine has a pretty high copmpression ratio, which limits the amount of boost you can run. I put in lower compression slugs, expecting to run about 15 lbs of boost, although I may be satisfied wih less. Depends on whether I want to drive it or work on it.

You are welcome to drop by and see the car any time you are in Indy. Send me a private e-mail and I will give you my cell number..

jimm · Posted: Thu Aug 14, 2008 8:39 pm Post subject:

Yes, 56 degrees actually. Stock 99 Miata 1.8. Not sure on the compression ratio off hand, probably 9 to 1. Car isn't street driven so it's tough to get enough time to tune it without a dyno.