Dave Robsons Challenger R/T
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Now there's an artist at workDave wrote:In case you are wondering how you fill holes in throttle blades? I take a tiny bit of brazing rod, drill the hole to the same diameter, and counter sink each side slightly.
Then, with the bit of rod in the hole, I Bananarama! in a vice to expand the brass rod and form a rivet. After filing flush I also stake the center of the rivet on each side with a center punch.
No-one will believe you...
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Dave-R
- Posts: 24752
- Joined: Sun Apr 18, 04 11:23 pm
- Location: Dave Robson lives in Geordieland
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I managed to aquire a free laptop to use on the car tuning.
It is over 10 years old and like a brick but it works.
It had Windows 95 on it but I managed to install '98 so it would run the Logworks 3 software.
With the laptop hooked up to the LM-1 unit I was able to monitor everything in real time!
I was also able to record directly onto the laptop.
So with that i was able to make the following changes.
Timing is now 18 degrees initial and 35 degrees total. At some point I will plot the exact timing curve on a graph.
Idle speed is now around 860rpm in Neutral and 800 rpm in "Drive".
Vacuum is 9 inches in neutral and 7.5 inches in Drive.
I fitted a spare 7.5 power valve in the center carb and i think it is effecting the idle mixture. So I will need a lower rated valve. Just not as low as the 2.5 I had in there before.
It is over 10 years old and like a brick but it works.
It had Windows 95 on it but I managed to install '98 so it would run the Logworks 3 software.
With the laptop hooked up to the LM-1 unit I was able to monitor everything in real time!
I was also able to record directly onto the laptop.
So with that i was able to make the following changes.
Timing is now 18 degrees initial and 35 degrees total. At some point I will plot the exact timing curve on a graph.
Idle speed is now around 860rpm in Neutral and 800 rpm in "Drive".
Vacuum is 9 inches in neutral and 7.5 inches in Drive.
I fitted a spare 7.5 power valve in the center carb and i think it is effecting the idle mixture. So I will need a lower rated valve. Just not as low as the 2.5 I had in there before.
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Anonymous
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Anonymous
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Dave-R
- Posts: 24752
- Joined: Sun Apr 18, 04 11:23 pm
- Location: Dave Robson lives in Geordieland
- Contact:
Yep. Then you record the whole run and play it back in the pits.Brutus wrote:I like the look of that setup Dave , saves a lot of messing around testing & tuning , can get it pretty near the mark right off the bat.
It would have been handy to fit a throttle position sensor too but it was going to be too fiddley.
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Anonymous
It will be interesting to see the results.
A TPS would have been handy. Whilst it would have no effect on the running, it could give you a correlation between throttle opening and vacuum, and your O2. It could have been particularly useful in maybe allowing you to 'stage' the mechanical transition of the outer carbs.
What we found with the Buicks (and what Buick found when they did the ECM software back in 1980) was that the 'load' on the engine when running at full chat (as on a dragstrip) is highest in the early stages of third gear. For this reason, Buick used the electronic sensor to electronically take few pounds of boost out of turbo in third and fourth. What all the aftermarket chips did was leave the boost in. The strange thing was that the Buick's ECM had no idea how much boost the car was running. It didn't have any feedback input, and, in fact, did not care.
Instead, Buick 'invented' a fictitious thing called LV8, which was a correlation of lots of sensor inputs and it calculated the 'load' on the engine. From the LV8 it could allow the ECM to jump through its tables (a 4x4 matrix - this was an 8 bit computer remember), and then trim even more in the secondary tables and calculate injector pulse width and timing advance/retard.
Where am I going with this ?
Checking the laptop after runs, revealed that the 'load' on the engine is actually fairly low at full chat through first gear. Many factors come into this. Drivetrain losses are minimal through first gear for one thing. The only real spike in 'load' comes with running sticky tyres and hitting the engine with that initial shock in getting the car moving.
Second gear also involve not too much load. The rev drop on 1-2 shift was short enough to have little effect. The turbo Buicks were stunning second gear cars as everything is runnng well. Load is lowish, boost can be stratospheric (not literally), timing is all in, injectors are flowing over 100% of duty cycle (in other words, continuously open). As long as the fuel holds up octane wise, it is impressive.
The shift to third gear was where load shot up. The rev drop was slightly greater, drivetrain losses are mounting greatly, aerodynamics are playing a part (despite the Regal being a pretty aerodynamic car). Boost did not tend to drop off though, (but then again, I never saw more than 5000rpm on a run on the car in the quarter mile) and you tended to get some knock (the engine jumped about a bit on the shift, despite restraints) and the fuel was always marginal here in the UK, despite some wicked additives.
Locking up the torque convertor a second or so after the shift to third added to the load, yet gave 3-4 mph extra at the top end. By the time you were in to third gear you also started to suffer boost creep as the wastegate would not stay open satisfactorily and started to shut and boost would creep. It was then a question of hoping the witches brew would be enough to get you to the end before the knock sensor buzzed itself off the dash. Water/alky injection in the later days killed that worry though.
Hopefully you will get enough info off your program, Dave.
Additional worthwhile information would be a knock sensor, a TPS and some feedback on timing tying it to rpms.
ATB
A TPS would have been handy. Whilst it would have no effect on the running, it could give you a correlation between throttle opening and vacuum, and your O2. It could have been particularly useful in maybe allowing you to 'stage' the mechanical transition of the outer carbs.
What we found with the Buicks (and what Buick found when they did the ECM software back in 1980) was that the 'load' on the engine when running at full chat (as on a dragstrip) is highest in the early stages of third gear. For this reason, Buick used the electronic sensor to electronically take few pounds of boost out of turbo in third and fourth. What all the aftermarket chips did was leave the boost in. The strange thing was that the Buick's ECM had no idea how much boost the car was running. It didn't have any feedback input, and, in fact, did not care.
Instead, Buick 'invented' a fictitious thing called LV8, which was a correlation of lots of sensor inputs and it calculated the 'load' on the engine. From the LV8 it could allow the ECM to jump through its tables (a 4x4 matrix - this was an 8 bit computer remember), and then trim even more in the secondary tables and calculate injector pulse width and timing advance/retard.
Where am I going with this ?
Checking the laptop after runs, revealed that the 'load' on the engine is actually fairly low at full chat through first gear. Many factors come into this. Drivetrain losses are minimal through first gear for one thing. The only real spike in 'load' comes with running sticky tyres and hitting the engine with that initial shock in getting the car moving.
Second gear also involve not too much load. The rev drop on 1-2 shift was short enough to have little effect. The turbo Buicks were stunning second gear cars as everything is runnng well. Load is lowish, boost can be stratospheric (not literally), timing is all in, injectors are flowing over 100% of duty cycle (in other words, continuously open). As long as the fuel holds up octane wise, it is impressive.
The shift to third gear was where load shot up. The rev drop was slightly greater, drivetrain losses are mounting greatly, aerodynamics are playing a part (despite the Regal being a pretty aerodynamic car). Boost did not tend to drop off though, (but then again, I never saw more than 5000rpm on a run on the car in the quarter mile) and you tended to get some knock (the engine jumped about a bit on the shift, despite restraints) and the fuel was always marginal here in the UK, despite some wicked additives.
Locking up the torque convertor a second or so after the shift to third added to the load, yet gave 3-4 mph extra at the top end. By the time you were in to third gear you also started to suffer boost creep as the wastegate would not stay open satisfactorily and started to shut and boost would creep. It was then a question of hoping the witches brew would be enough to get you to the end before the knock sensor buzzed itself off the dash. Water/alky injection in the later days killed that worry though.
Hopefully you will get enough info off your program, Dave.
Additional worthwhile information would be a knock sensor, a TPS and some feedback on timing tying it to rpms.
ATB
Ive got a spare GN Harness, ECU and all the sensors if you wanna hook it all up
No Joking aside the Knock sensor saved my Skyline the first time.
The chip in my GN lowered the boost through the gears 22psi in 1st, 18 2nd and 14-15 3rd as the load increased
Knock sensor always backed it off with bad Gas, but its a saver
No Joking aside the Knock sensor saved my Skyline the first time.
The chip in my GN lowered the boost through the gears 22psi in 1st, 18 2nd and 14-15 3rd as the load increased
Knock sensor always backed it off with bad Gas, but its a saver
ALL KILLER NO FILLER
Nostalgia, its not what it used to be.
Carbon footprint of a Saturn V
Nostalgia, its not what it used to be.
Carbon footprint of a Saturn V