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Discussion Starter · #1 ·
For you guys with a WB-

What A/F do you see when spooled up on the line for launch? :)
 

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Steve Wood said:
For you guys with a WB-
What A/F do you see when spooled up on the line for launch?
Typcially, mid 12s, on my car.
I've also seen as low as a 10:1.
 

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Discussion Starter · #5 ·
scott wile said:
what's better? low timing & lots of fuel, or lots of timing less fuel? What about with a t-brake?

-scott wile
Scott, that was going to be my next question :)

The richer the a/f mixture, the faster it burns, which means one needs less timing. If the timing is reduced enuf, this means you are spitting a lot of heat out the exaust to the turbo which spools it quicker which is a benefit if you are running a larger set up...easier on the tranny if you can wind up the turbo quicker.

From a theoretical stance, peak torque comes at a richer a/f than does peak horsepower-talking about cylinder pressures.

It would seem to me it would be better to launch richer/lower timing, and then lean down a bit, and use a bit more timing after launch once the engine is in it's rpm band that is going to be pretty narrow afte the 1-2 shift.

Now, fuzzy logic is my normal state of reasoning...so take it with a grain of salt. :)

Seems to me one has to break down the track in segments...short times, 1/8th and so on..and try to optimize each part. It may take a different philosophy for each segment with regard to fuel and timing...at least in theory. :dunno:
 

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rich and drop timing to 16 degrees which will spike the heat and and it will spool super quick,
once car rolls lean it to about 12:1 and bring in the timing , i launch with 16 degree then move up in first gear (28) then lower it a degree at second(27) , then further drop it in third (22-23)
 

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thanx Steve - I think my ME-R chip does just the opposite.

-scott wile
Steve Wood said:
Scott, that was going to be my next question :)

The richer the a/f mixture, the faster it burns, which means one needs less timing. If the timing is reduced enuf, this means you are spitting a lot of heat out the exaust to the turbo which spools it quicker which is a benefit if you are running a larger set up...easier on the tranny if you can wind up the turbo quicker.

From a theoretical stance, peak torque comes at a richer a/f than does peak horsepower-talking about cylinder pressures.

It would seem to me it would be better to launch richer/lower timing, and then lean down a bit, and use a bit more timing after launch once the engine is in it's rpm band that is going to be pretty narrow afte the 1-2 shift.

Now, fuzzy logic is my normal state of reasoning...so take it with a grain of salt. :)

Seems to me one has to break down the track in segments...short times, 1/8th and so on..and try to optimize each part. It may take a different philosophy for each segment with regard to fuel and timing...at least in theory. :dunno:
 

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pacecarta---What controller do you have that allows all that timing adjustment?
 

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Discussion Starter · #10 ·
scott wile said:
thanx Steve - I think my ME-R chip does just the opposite.

-scott wile
Scott...I run an ME-R as well. I forget how the latest version does it. I know Steve has played with several techniques. Mine is pretty rich, but, I have not looked at the timing...my converter has lost a 1000 rpm in stall so I am not getting much, if any, boost, before the brakes let go...and I am afraid of trying to force it against the tranny brake because I think something will burn up first.. :D
 

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Here goes... With an automatic car when you are trying to build boost against a converter with a transbrake or a footbrake, HIGH timing and lean mixture will get you the quickest spool up, typically 12.5-13:1 with 40degrees of timing to get it "over the hump". The theory is correct in low timing, rich a/f but the problem is that removing all the timing wont let the engine produce any torque to get the converter up where it needs to be.If you are using a clutch it works just the opposite.With a clutch, you cannot load the engine, you need to pull the timing out usually back to 5 degrees total or so and run the A/F at 10:1, this causes unburned fuel to explode in the pipe and spool the turbo instantly, wont work with a converter unless it is WAAAAY loose!
 

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Discussion Starter · #13 ·
thanks for the insight, Bill :)
 

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EightSecV6 said:
Here goes... With an automatic car when you are trying to build boost against a converter with a transbrake or a footbrake, HIGH timing and lean mixture will get you the quickest spool up, typically 12.5-13:1 with 40degrees of timing to get it "over the hump". The theory is correct in low timing, rich a/f but the problem is that removing all the timing wont let the engine produce any torque to get the converter up where it needs to be.If you are using a clutch it works just the opposite.With a clutch, you cannot load the engine, you need to pull the timing out usually back to 5 degrees total or so and run the A/F at 10:1, this causes unburned fuel to explode in the pipe and spool the turbo instantly, wont work with a converter unless it is WAAAAY loose!
Is this aimed at a 9 sec, or faster full-on race car?.

IMO, I'd stage without anything near that extreme on a street car.
Tha 40d comment sure looks to be aimed at racing fuel, rather then pump gas, or a lot of cam to be bleeding off building much compression.

FWIW, Jack C, and Cal H, can verify that what I'm doing works, as they've driven my car.
 

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Doc1of7 said:
Is this aimed at a 9 sec, or faster full-on race car?.

IMO, I'd stage without anything near that extreme on a street car.
Tha 40d comment sure looks to be aimed at racing fuel, rather then pump gas, or a lot of cam to be bleeding off building much compression.

FWIW, Jack C, and Cal H, can verify that what I'm doing works, as they've driven my car.

how fast is your car?
 

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Discussion Starter · #16 ·
if it helps, I was interested in 10-11 second cars with 231" blocks :)
 

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EightSecV6 said:
Here goes... With an automatic car when you are trying to build boost against a converter with a transbrake or a footbrake, HIGH timing and lean mixture will get you the quickest spool up, typically 12.5-13:1 with 40degrees of timing to get it "over the hump". The theory is correct in low timing, rich a/f but the problem is that removing all the timing wont let the engine produce any torque to get the converter up where it needs to be.If you are using a clutch it works just the opposite.With a clutch, you cannot load the engine, you need to pull the timing out usually back to 5 degrees total or so and run the A/F at 10:1, this causes unburned fuel to explode in the pipe and spool the turbo instantly, wont work with a converter unless it is WAAAAY loose!

I would use this as a guideline Steve, different cars need different things so your results may vary but I know this will work.
 

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EightSecV6 said:
how fast is your car?
Slower then 9's.
And, about all the fun I can stand, for a street car.

Beings that it's a street car, I haven't run through a 1/4 in years.

BTW, I can *park* in launch mode as long as I want, ie 3,000 RPM, and 4-6 PSI.
 

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Doc1of7 said:
Slower then 9's.
And, about all the fun I can stand, for a street car.

Beings that it's a street car, I haven't run through a 1/4 in years.

BTW, I can *park* in launch mode as long as I want, ie 3,000 RPM, and 4-6 PSI.

put it in drive and try to launch it at a realistic RPM and tell us where the boost is :D
 

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EightSecV6 said:
put it in drive and try to launch it at a realistic RPM and tell us where the boost is :D
Meaning what?..

I can set the stage RPM from 650 to 6,375. Depending on how much timing I pull more or less sets the boost.
Boost while staging isn't critical, it's what happens when you first leave that is. If you want to run 40d when under boost while staging, fine, but, you're going to be right at the edge of detonating the motor. Not to mention the excessive heat in the chamber is also going to make it more prone to detonate, once you do leave.

I just can't see any advantage in running a lot of timing, when retarding it will do the same thing, and be less stressful on the engine.
 
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