88-94 5.7 Suburban A/C Diagnosis and Tuning

[Wildblue19]

I see a mount for dual compressors. Does that mean you are adding a 2nd condenser as well. The single condenser is more of a limitation than the compressor in a dual evaporator system.

Yes, dual condensers!

 

[Wildblue19]

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They're multiplying!

 

[1998_K1500_Sub]

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They're multiplying!

Are you planning to transport frozen meat with that rig???

Do tell!

What compressors are those?

Planning to engage the compressors simultaneously, or insert a short delay between them so as to manage the start-up load?

It looks like you’ll have good belt wrap around those pulleys by using that intermediate idler.

I wonder if the tensioner will be suitable.

I can’t wait to see where this is going…

 

[Schurkey]

Who engineered that 2-compressor adapter bracket?

Any problems with the OEM aluminum bracket having all the load in front, instead of being split front/rear? The belt tension would tend to twist the compressors "downward", leading to torque on the front half of the OEM bracket.

 

[1998_K1500_Sub]

Any problems with the OEM aluminum bracket having all the load in front, instead of being split front/rear? The belt tension would tend to twist the compressors "downward", leading to torque on the front half of the OEM bracket.

Looking at the mounting method, with the concentric collars between the front and rear of the AL bracket, I'm thinking the forces will be managed by the bosses on both sides (F&R) of that bracket, which is good. This assumes the collars are tightly fit (few .001 between ID and OD).

Notice too the new bracket engages the OE idler mounting boss.

Bolting those two compressors together creates a single, larger unit of mass (lumped element, so to speak) with its mass center located beyond the AL bracket, hanging "out to the left" in the picture. The dynamic loads (road bounce, clutch engagement, ...) won't be as kind to the OE AL bracket; those forces, acting from farther away on the bracket, make it more challenging for it to manage them... stress, strain.

Maybe there's a support rod(s) that's not visible in the picture. Two or three of those would aid immensely.

But hey, no risk no reward! Besides, since we don't know the intentions, we can't judge

 

[Wildblue19]

What compressors are those?

Planning to engage the compressors simultaneously, or insert a short delay between them so as to manage the start-up load?

GM V7 compressors, I used a 98-02 S10 2.2L as the search vehicle when parts buying. The flat front mounting pads are what are making this doable. There are also threaded holes on the rear of the compressor, which I may tie into to support the cantilevered load as @Schurkey commented on. I haven't made that bracket yet but I plan to do it soon.

Clutch delay is a good question, I am going to keep it simple for now and Wire them in series but I can get fancy with some microcontrollers to add delay if it loads down the engine.

The spacers behind the bracket are shimmed to be zero play so the front and rear of the OE cast bracket are used

 

[1998_K1500_Sub]

GM V7 compressors, I used a 98-02 S10 2.2L as the search vehicle when parts buying. The flat front mounting pads are what are making this doable.

I'll assume, since they're variable displacement, they won't cycle nearly as much.

Clutch delay is a good question, I am going to keep it simple for now and Wire them in series but I can get fancy with some microcontrollers to add delay if it loads down the engine.

There are stand-alone "delay relay" devices that might do the job for you.

The spacers behind the bracket are shimmed to be zero play so the front and rear of the OE cast bracket are used

I was pretty sure you had given it some thought

 

[Wildblue19]

I'll assume, since they're variable displacement, they won't cycle nearly as much.

I am hoping so too. Still, I have several of the control valves to vary the destroke point and also will be wiring in low side safety switches for redundancy. I am glad I added a reciever drier to the rear system in my earlier mods; that will make this conversion much easier! The immediate issue now is finding a belt that fits at appx 128.75" length

 

[Wildblue19]

I created a thread with an interesting idea here regarding delay relays.

Furnace time delay relay for AC staging

Anyone here know how furnaces are wired? It is truck related I promise. Long story short, I am running 2 AC compressors in my truck and I'd like a delay between the two compressors turning on. I don't want to load down the engine with two compressors switching at once. There's also a...

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