My truck, a work in progress
Monday, May 10, 2004
Part 16: Dyno numbers...(5-10-2004)
Just got back from Dynospot Racing, a local dyno shop, and I have some numbers to share for the turbo truck:
The max numbers are [...drum roll...]: 222.4 hp, 243 ft. lbs. @ 15 psi., as measured at the rear wheels. :-)
I am pretty pleased, as these numbers were obtained on 91 octane pump gas! This thing is a blast to drive, and makes me want to find some speed rated light truck tires, if there is such a thing.
When I first started this project, I felt that it might be possible to deliver as much as 300 hp to the rear wheels on pump gas and turbo alone. Obviously, it wasn't possible to run enough boost and advance on pump gas to do that, at least not by me. For the record, I have no doubt that with racing fuel I could easily run enough boost and advance to make 300 wheel hp...but that wasn't what I was after. I wanted a truck that made turn-key power on pump gas, and I'm pretty pleased with what I have.
The motor only has 1000 miles on it, so I may see another 5-10 hp once the rings fully seat. Also, I've seen all sorts of numbers tossed around for driveline losses on 4x4's, but even a middle of the road number like 25% puts me at 300 hp at the flywheel, which is impressive. I think any way you measure it, I have more than doubled the stock 136 flywheel hp, which is pretty damn good. This motor rocks! Kudos to Tim @ D.O.A. for building a solid, deep-breathing platform utilizing his own custom head porting and turbo cam grind. And while some of these parts came right off the shelf, many parts (such as the throttle body + linkage, intercooler setup, and the exhaust, to name a few) had to be made by hand. Building this motor has been a lot of work! I don't know if I'd do it again, but it's pretty fun to drive the end result :-)
So what's next? Driving it and enjoying it! And if I ever get the urge for more, there's always water injection (even if it does violate my "only pump gas" rule) ;-)
-Jeff
Just got back from Dynospot Racing, a local dyno shop, and I have some numbers to share for the turbo truck:
The max numbers are [...drum roll...]: 222.4 hp, 243 ft. lbs. @ 15 psi., as measured at the rear wheels. :-)
I am pretty pleased, as these numbers were obtained on 91 octane pump gas! This thing is a blast to drive, and makes me want to find some speed rated light truck tires, if there is such a thing.
When I first started this project, I felt that it might be possible to deliver as much as 300 hp to the rear wheels on pump gas and turbo alone. Obviously, it wasn't possible to run enough boost and advance on pump gas to do that, at least not by me. For the record, I have no doubt that with racing fuel I could easily run enough boost and advance to make 300 wheel hp...but that wasn't what I was after. I wanted a truck that made turn-key power on pump gas, and I'm pretty pleased with what I have.
The motor only has 1000 miles on it, so I may see another 5-10 hp once the rings fully seat. Also, I've seen all sorts of numbers tossed around for driveline losses on 4x4's, but even a middle of the road number like 25% puts me at 300 hp at the flywheel, which is impressive. I think any way you measure it, I have more than doubled the stock 136 flywheel hp, which is pretty damn good. This motor rocks! Kudos to Tim @ D.O.A. for building a solid, deep-breathing platform utilizing his own custom head porting and turbo cam grind. And while some of these parts came right off the shelf, many parts (such as the throttle body + linkage, intercooler setup, and the exhaust, to name a few) had to be made by hand. Building this motor has been a lot of work! I don't know if I'd do it again, but it's pretty fun to drive the end result :-)
So what's next? Driving it and enjoying it! And if I ever get the urge for more, there's always water injection (even if it does violate my "only pump gas" rule) ;-)
-Jeff
Friday, May 07, 2004
Part 15: Tuning day (5-6-2004)
Spent a few hours with Dan Fodge yesterday tuning the truck (Fodge Engineering, 3250 Unit H, Monier Circle, Rancho Cordova CA, (916) 851-9111). We didn't do any dyno pulls, but we did do about 2 hours of road tuning. The motor is now running very well -- 15 pounds of boost with no pinging, and plenty of acceleration, and max EGTs of ~1510°F under sustained boost. This is a stable and workable tune. Hooray!!
I'm posting some screen shots of the air/fuel, volumetric efficiency, and spark tables because someone may be curious.
A few things of interest:
1. Notice that to eliminate pinging at 15 psi, we had to drop the timing down to 9° and max out the a/f ratio. This is on 91 octane pump gas, so I suppose this is to be expected. It does make me want to take a long, hard look at water/methanol injection, as I'm sure it would allow me to run more timing and more boost...but it's also an additional complication in an already complicated setup, and it raises some fears about what would happen if the water injection failed at a key moment.
2. Dan was able to fine tune some other areas of the fuel map for fuel economy (the cells with the 14:1 a/f ratios.
3. I drove the truck hard for seven hours yesterday (2.5 hours in each direction to his shop, plus 2 hours of tuning time), and it drove like a champ. That may not seem like a big deal to some folks, but if you've been following my progress with this motor, seven hours of hard driving is a real confidence builder ;-)
Maybe I'll have some new dyno numbers in the next post...
Spent a few hours with Dan Fodge yesterday tuning the truck (Fodge Engineering, 3250 Unit H, Monier Circle, Rancho Cordova CA, (916) 851-9111). We didn't do any dyno pulls, but we did do about 2 hours of road tuning. The motor is now running very well -- 15 pounds of boost with no pinging, and plenty of acceleration, and max EGTs of ~1510°F under sustained boost. This is a stable and workable tune. Hooray!!
I'm posting some screen shots of the air/fuel, volumetric efficiency, and spark tables because someone may be curious.
A few things of interest:
1. Notice that to eliminate pinging at 15 psi, we had to drop the timing down to 9° and max out the a/f ratio. This is on 91 octane pump gas, so I suppose this is to be expected. It does make me want to take a long, hard look at water/methanol injection, as I'm sure it would allow me to run more timing and more boost...but it's also an additional complication in an already complicated setup, and it raises some fears about what would happen if the water injection failed at a key moment.
2. Dan was able to fine tune some other areas of the fuel map for fuel economy (the cells with the 14:1 a/f ratios.
3. I drove the truck hard for seven hours yesterday (2.5 hours in each direction to his shop, plus 2 hours of tuning time), and it drove like a champ. That may not seem like a big deal to some folks, but if you've been following my progress with this motor, seven hours of hard driving is a real confidence builder ;-)
Maybe I'll have some new dyno numbers in the next post...
