Sometimes you just gotta start over....
- Thread starter JayC
- Start date
Dial in a good mixture first before playing with the timing. Mixture strength will slightly affect the required timing, so mixture strength should always be ironed out first. The flame speed changes from rich to lean. I recently retarded my timing a few degrees while still working on dialing in the fuel curve and found no change. Except that now, I'm doing a burnout across the finish line with a little less boost. 254 kPa.
Watch the plugs. Those will tell you where your mixture strength is and if there's room for more timing. Get the mixture to burn some plating off a thread before playing with timing. The ground strap will tell you where your timing is. When you see some plating burned off the first thread, note your EGT. That will most likely become a very key number for future tuning.
- Joined
- Dec 7, 2002
:biggrin: FOOOOOOOOOOOO NINEIEEEEEEEEEEEEEEE TWOOOOOOOOOOO:biggrin:
JZ 97 SS 1500
Turbocharger Engineer
- Joined
- Jul 2, 2001
Glad you like the Borgs. Let me know when you need bigger ones :biggrin:
Holy Crap!! that's going to be one bad a$$ runner when tuned in!!!!
BTW, Shane what's the full designation on the 75's? I'd like to see if my Son-in-law knows them. He's a turbo design engineer at BW over in Ashville.
JZ 97 SS 1500
Turbocharger Engineer
- Joined
- Jul 2, 2001
Dave they are the S400Sx's. He will know the complete line just off that naming system. Direct part # is 177101 for that particular unit. We keep them in stock with our Turbodiesels.net shop.
If they put out what they are supposed to he won't need bigger ones
I think he was referring to when we put a BB in!
That would be awesome!
JZ 97 SS 1500
Turbocharger Engineer
- Joined
- Jul 2, 2001
They definitely will, but Jay always wants more power...lol
The plugs have no burn marks on the base or threads. The timing mark is still on top of the ground strap. Way to much fuel in it for now. On the dyno it only made around 800 at this boost level. With 12 psi on the launch and 24 with in .5 seconds. These turbos really shine above 30 psi. We are using tires from a car that runs 4.20's with 30 runs on them. they replace them at 25 or so. It does like timing at this level. drop a degree or two and power falls way off. We are adjusting the tune and chassis. Installed lighter rear springs and adjusted shocks. The video was at 5500 rpm launch will be higher next time. Wheel speed is still slow through .75 secs. Needs more power earlier in the run. And we had snow flurries today. It will be a week or so before the weather clears up. We are hoping to go to VMP as soon as the weather allows. Or a trip to southern states may be needed. We got the shifter problem fixed today, A problem with the shift box. Trans has good pressure and convertor looks like it is on the right track.
Remember guys Randy is NEW to the Buick V6 deal:biggrin: Between Jay and his expertise I feel so confident about things. Randy knows a race car:biggrin:
If the weather is clear come up to Atco,NJ on Sunday, 11/30, for the annual GN Mustang shootout. Fast 1/4 mile track, great facility, and because they moved it back a week to the 30'th I'm betting the turnout will be off a lot so you could get in all the passes you wanted. Yeah, it's a haul for you, but you did miss Cecil so you owe us northeast guys 
. Seriously, looking great and slowly sneaking up on the tune is definitely the way to go. I can't wait to see you run in person.
. Seriously, looking great and slowly sneaking up on the tune is definitely the way to go. I can't wait to see you run in person.Thanks JZ! I gave him the part number today, and he pretty much knew what they are, and is looking up the BOM this morning to "spec" them out. I'm over here at their house this weekend.
He (John) visits the board on rare occasions and asked, if you guys don't mind, the possibility of getting some engine data, he'd like to "spec" some turb's out. Would you mind if he contacted you here JZ? He works out of the Ashville office here and has moved up from design engineering to lead applications engineer for off road.
If you see GNX405 on the board that's him.
You may find out that you don't need to launch at a higher rpm as you lean on the mixture a little at a time. If you're that rich, there will be plenty of power on hand as you lean on it. Just keep a sharp eye on those plugs. They are your best window into the engine with alcohol.
Depending on how rich you are, you could find yourself leaning out the mixture several times in small steps before you see signs of heat on the plug. Alcohol runs surprisingly well at very, very rich mixtures. I've been 20% rich at times. It seemed like forever leaning the mixture in. You should see times increase with each step, and should definitely feel the launch pull increase with each step. Don't get too anxious in the process and start taking larger jumps in the leaning process. 3 percent at a time should be fine. As you see the heat starting to come in, switch to 1 or 2 percent changes. You think the power is great being at this rich level, just wait. You're going to love it.
As a comparison note, I've found that my setup is running best with the base burned completely off and the first thread of the plug just starting to show heat, or more precisely, slightly less than half of the first thread burned off. The plating that is.
The ground strap is showing heat less than half the way.
For me, you're in the favorite stage of the tuning. You're going to find a lot of untapped HP as you lean her in.
One more note. As you lean her in, revisit the timing to make sure you're still losing power when you take a few degrees away. If you find at some point that you didn't lose a bunch of power after taking a few away, make that your new timing. The flame speed is going to change as you lean on the mixture.
A note on ignition timing. Do not assume that methanol will require more ignition advance than with gasoline. In an overly rich mixture, it is generally true that you will need to advance the timing due to the slower flame speed of an overly rich mixture. As you lean on the mixture to find more hp, you should find that flame speed will increase requiring less spark lead. Less spark lead is a good thing. Less pumping losses. In some cases, it was found that an engine on methanol with equivalent ratios, compared with gasoline, required less spark lead than when on gasoline. Don't get carried away by the myth that all methanol engines need much more spark lead than when on gasoline.
You may also find that there is a very wide optimum timing setting for any given rpm/boost setting. The range can be as wide as 7 degrees with no appreciable change in hp. The width of the range can also change with differing rpm/boost settings with the same engine.
You may also find that there is a very wide optimum timing setting for any given rpm/boost setting. The range can be as wide as 7 degrees with no appreciable change in hp. The width of the range can also change with differing rpm/boost settings with the same engine.
