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Horsepower and A/C

3K views 20 replies 11 participants last post by  ScottLC 
#1 ·
Exactly how big can I build my LT1 without deletin my A/C? Wanna add sum horses AND keep my A/C....
 
#3 ·
Aw ok. Thanx man I had heard a few rumors that in certain builds I may have to delete my A/C. Thanx 4 clearing that up 4 me..
 
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#4 ·
When you get your car reprogrammed, set the
"A/C Clutch Disable %TPS Threshold"
to something unusually low, like 37% or something.

Mine is a daily driver; my A/C Clutch Disable %TPS Threshold is set at 66%, with no issues.
Curious about this one. I have a old 92 Buick that when under load (going up hills, etc) the AC would sort of "drop off" and then back on once your off the throttle a little. I always assumed this was a power saver and also designed to give the V6 more pwer when needed.

On our cars I was not aware we even had such a feature on our AC. I just figured the clutch is engaged thru the switch and either runs all the time or it doesn't. So do our cars have a similar function to disable or cut back the AC somehow and could you share some more details of this and what/how it does it type of thing?? Again, just curious....thx.
 
#9 · (Edited)
Too many people think what you see on a race car is what you have to do. They take the AC out because of weight and it has no value for going fast.

I have working AC at 1400 plus HP so the amount of HP is not an issue. If anything its less of an issue because you never feel the motor pull down when its running like you do on a more stock Impala.

The trick is keeping the belt on as you go up in HP. You can even run your AC at the track if you do a few things. My AC is on during every pass I make if it's hot out. And the look on their face at the ET shack when you crack your window so they can hand you your time slip with cold air coming out as they hand you a 9 second time slip:) That never gets old!!

Keep your AC and let all the others sweat to death in thier cars. You can have AC and still go fast.
 
#10 ·
You can even run your AC at the track if you do a few things. My AC is on during every pass I make if it's hot out.
They don't ask you to turn it off when water drips on the track?
 
#12 ·
on all my recent LT1 tunes I shut off the AC clutch at 50-60% Throttle
then when you back out of the throttle it kick back in all on it's own

stock is 95%

on LS1/2/3/6/7 ect you get more logic than just TPS on off:
RPM Disable
RPM ReEnable
TPS Disable
TPS ReEnable
 
#18 ·
Just one thing to watch for, if the compressor is not 'off' long enough, it's a hard hit on the restart. Much like house ac's now that typical 3 minute timer. It ensures all the liquid refrigerant has evaporated. Don't know if the ecu has a built in delay for the restart. I don't recall seeing such in the definition file.
It may warrant having it high enough so it doesn't get constantly hammered by restarts.
 
#13 ·
if the AC clutch is on and stays on as the Engine spins up it will be fine
..as long as the belt stay on track...

But..
having the clutch apply at high RPM can immediate lead to compressor or clutch death

the clutch basically drops on to the spinning pulley from zero RPM!!!

a 6K RPM Delta clutch drop is killer for just about any kind of consumer style clutch drive line or otherwise
 
#14 ·
You are dead on!! The last part I have in my setup to make this work is the clutch wire runs to a relay that is controlled by an RPM window. I have it set so it will kick out the clutch at 3000 RPM's and above. It's needed because when I let off the gas at the end of a pass the engine is still spinning close to 7000 RPM's and you don't want the clutch to go live spinning that hard. For just driving around the car never see's anything over 3k so the AC stays on.

And with the TPS tables it cuts the clutch out as soon as I leave the line because of the 100% reading.

So here is how I see it. Removing your AC will not even get you a tenth of a second at the track. So is not have AC worth that to you? And a setup like this is totally automatic, you don't have to do anything so you can't screw it up. The only mistake you can make is forgetting to drain the tank after each pass or forgetting to leave the tank open when you're just driving it on the street.

Just remember, if you're runnning against me at the track, I'm in AC the whole time:)
 
#15 ·
or...

... 'just' drop this between the frame rails (you may have to move them over a bit) and you won't have room for A/C - so it renders the point moot.

:D



(sorry, it was just too good a discussion up to this point.)

.
 
#16 ·
Why not just hang a window AC unit from a house in one of the back windows and power it with a a/c converter:)

Somewhere I have a picture of an old beater that someone did that.
 
#17 ·
cwm2 .....Yeah; I've seen a picture like that.....may be the same picture. I LOL'ed real good ;) ......

KW
 
#20 ·
Not saying liquid at the compressor but in the condenser. Pressure will rise rapidly as the 'empty' space in front of it can be greatly reduced. It's a spike compared to normal running state.
 
#21 ·
One reason people still seem to think they need to delete their AC is carryover from the past; certain factory performance engines in the 60's and early 70's just did not idle well with AC at any "normal" RPM. The (lazy)"solution" was to remove the AC option with certain engine selections. My first 'vette was a '71 LT1 solid-lifter with automatic which supposedly you could not get with AC. They actually wound up sending out a few anyway(wish I still had it) and I never saw the problem but that was the logic....
 
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