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Santa pod tomorrow 19th
- Thread starter jonbills
- Start date
Yep, 12.8 is quick! 
Alphabettispaghetti
Club Member
I don't understand 1/4 mile stuff but I know that's quick.
Alphabettispaghetti
Club Member
It is very pleasing. But I need to be able to repeat it. I wish I knew what I did on that run
I know I didn't get much wheel spin at the start and the engine revved out nicely, but how that came about, I've no idea!
did you get your car back to the dyno to see how healthy it is now?
johnymd
Club Member
Superb time there Jon. Looking at the time slip, your start was not really any better than the others but the terminal was up by quite a bit. This indicates a marked increase in power on that run. I can't explain why.
You do have a lot of scope on your 60' time though. On my good runs I can do a 1.65s and with sticky tyres you should be able to get down there. The start is where make or lose time. My last 2 visits I've been running the same 60's as you which has meant that I'm down by a second or more.
You do have a lot of scope on your 60' time though. On my good runs I can do a 1.65s and with sticky tyres you should be able to get down there. The start is where make or lose time. My last 2 visits I've been running the same 60's as you which has meant that I'm down by a second or more.
Thanks John,
First 2 runs I had lots of wheel spin but the engine went well, then I let the tyre pressures down to 20 something psi. 3rd run I got a decent start but the engine was misfiring from 6.5k or so. 5th run was similar and misfiring at 6k. I must have got round quicker for the 4th because it revved out ok.
The misfiring is carbon fouling from sitting too long in the fire up lane.
I read today that more advance at idle will raise the plug tip temp, so I might try reconnecting the vacuum advance.
I don't think I'm going to beat 2s for 60ft until I've got a Quaife fitted tho.
First 2 runs I had lots of wheel spin but the engine went well, then I let the tyre pressures down to 20 something psi. 3rd run I got a decent start but the engine was misfiring from 6.5k or so. 5th run was similar and misfiring at 6k. I must have got round quicker for the 4th because it revved out ok.
The misfiring is carbon fouling from sitting too long in the fire up lane.
I read today that more advance at idle will raise the plug tip temp, so I might try reconnecting the vacuum advance.
I don't think I'm going to beat 2s for 60ft until I've got a Quaife fitted tho.
I used to run the R888's at 11 psi
Brisk clutch release at around 4500, cross the line in 3rd at around 8000
Terminal speed is the biggest indicator of power and often paints a more realistic picture of the performance of the engine/car package as it is more consistent and doesn't get skewed (as much) by poorer gearshifts
In 3rd we were crossing the line at just under 112 for a 12.453 ET
Brisk clutch release at around 4500, cross the line in 3rd at around 8000
Terminal speed is the biggest indicator of power and often paints a more realistic picture of the performance of the engine/car package as it is more consistent and doesn't get skewed (as much) by poorer gearshifts
In 3rd we were crossing the line at just under 112 for a 12.453 ET
johnymd
Club Member
How rich is it running at idle? I hear lots of people talking about fowling the plugs at idle but I would of thought once you rev the engine it should clear. Maybe run a hotter plug. Which are you running? 7?
Interesting what you say about advancing the idle ignition increasing the tip temp. The laws of physics with regard to ignition timing can be simplified to these statements when referring to where the energy goes when you ignite the fuel:
Retarded ignition: The burn process is started late in the compression cycle and the burn continues to when the exhaust valve starts to open causing the energy/heat to be waisted and comes out of the exhaust (seen as high exhaust gas temps)
Advanced ignition: The burn process is started early in the compression stroke and some of the energy is waiste by trying to slow down the piston before it reaches TDC. This will put a lot of force on the piston, conrod and into the crank and you will see your oil temps go up as the energy/heat is transferred into the engine components. The combustion temps will go up as you said.
Correct ignition: This is the perfect point between retarded and advanced. Exhaust gas temps reduced but not to the extent that the oil temp rises. Maximum power is achieved when 50% of the burn has occurred at around 15* after TDC.
Interesting what you say about advancing the idle ignition increasing the tip temp. The laws of physics with regard to ignition timing can be simplified to these statements when referring to where the energy goes when you ignite the fuel:
Retarded ignition: The burn process is started late in the compression cycle and the burn continues to when the exhaust valve starts to open causing the energy/heat to be waisted and comes out of the exhaust (seen as high exhaust gas temps)
Advanced ignition: The burn process is started early in the compression stroke and some of the energy is waiste by trying to slow down the piston before it reaches TDC. This will put a lot of force on the piston, conrod and into the crank and you will see your oil temps go up as the energy/heat is transferred into the engine components. The combustion temps will go up as you said.
Correct ignition: This is the perfect point between retarded and advanced. Exhaust gas temps reduced but not to the extent that the oil temp rises. Maximum power is achieved when 50% of the burn has occurred at around 15* after TDC.
