88-94 5.7 Suburban A/C Diagnosis and Tuning

[Wildblue19]

Seller on ebay had a good selection of control valves for cheap, I got 37.5, 40, 42, 45 for about 20 dollars total to my door. Rather have them if I need them. And the ones I don't use, if you need them with your friends conversion you can have them.

Going to have to wait about 2 weeks until I can test fit the V7, but Yes the 2.2L Sonoma 6 groove radial mount should be the correct pattern and only need swimming for alignment

 

[L31MaxExpress]

Seller on ebay had a good selection of control valves for cheap, I got 37.5, 40, 42, 45 for about 20 dollars total to my door. Rather have them if I need them. And the ones I don't use, if you need them with your friends conversion you can have them.

Going to have to wait about 2 weeks until I can test fit the V7, but Yes the 2.2L Sonoma 6 groove radial mount should be the correct pattern and only need swimming for alignment

Forgot one thing on that swap. The early LS1 F-cars have a different crank pulley spacing than a truck. Hopefully I can figure out a way to mount that V7. For now though it has cooled down and may be a next spring project. I am also trying to get my hands on a compressor performance chart for the 10S20F that GM used in that van. Its supposed to be a 200cc compressor. When I was checking everything with the IR thermometer I found the clutch hub 50°F hotter than the compressor. I am intending on using a contactless tachometer to measure the clutch hub rpm. I am going to check the clutch air gap this weekend as well as replace the belt with a stretch fit and remove the ac tensioner. Never have liked those small tensioners. Fingers crossed the thing just has a slipping clutch or belt.

 

[Wildblue19]

Question, are you reaching out to manufacturers directly for the performance charts @L31MaxExpress ?

I am also seeing a HD6 compressor in the radial mount case and am wondering how it performs vs the V7.

 

[L31MaxExpress]

Question, are you reaching out to manufacturers directly for the performance charts @L31MaxExpress ?

I am also seeing a HD6 compressor in the radial mount case and am wondering how it performs vs the V7.

I had a HD6 on my 1983 G20 van after I converted it to a 1992 G20 TBI serpentine belt system. It is similar in displacement and performance to the R4. From memory it is 10 cid. It operates more smoothly and quietly than the R4 and the unknown mileage/age used one worked for years.

88969 is a Four Season upgrade number for that application, but finding information is like pulling hens teeth. Looks to be a Valeo unit.

 

[L31MaxExpress]

To answer your question. I have reached out to numerous manufacturers on compressors and very few have the full details.

On a side note, do you work for reversionraceworks? Definitely some pretty cool dash related stuff. I would love to have a 10" digital dash in the Express van myself, especially since the speedometer is getting glitchy anyway. The Express/Savanna and Astro/Safari vans used the same clusters for a number of years.

 

[Wildblue19]

To answer your question. I have reached out to numerous manufacturers on compressors and very few have the full details.

On a side note, do you work for reversionraceworks? Definitely some pretty cool dash related stuff. I would love to have a 10" digital dash in the Express van myself, especially since the speedometer is getting glitchy anyway. The Express/Savanna and Astro/Safari vans used the same clusters for a number of years.

I do, part time design work and consulting. If you want to get on the radar, I'd just send an email on the RR website contact page to go to everyone and I can share it more easily. I don't want to derail the thread too much, but we do all kinds of custom requests.

 

[L31MaxExpress]

I do, part time design work and consulting. If you want to get on the radar, I'd just send an email on the RR website contact page to go to everyone and I can share it more easily. I don't want to derail the thread too much, but we do all kinds of custom requests.

Very cool.

Back to the question though the V7 is probably the largest displacement GM compressor available save for the A6. The V7 is probably more efficient than th A6 volumetrically being a much newer design. The A6 moves 42,000 BTU at 4,000 rpm. The V7 moves 47,800 btu at 4,000 rpm based off the performance chart I found. I cannot find a maximum displacement for the V7 but I assume it has to rival the A6 given its performance. By comparison I want to say the chart I saw for the DA6, HD6, HR6 (all just improvements of the same 10 cid, 6 cylinder compressor) showed 36,000 or 38,000 BTU @ 4,000 rpm. The BTU rating at 4,000 rpm was a common point for GM to rate the maximum continuous operation of their compressors. Many of the older GM compressors were designed before overdrive/lockup transmissions were a thing hence the maximum BTU capacity being reached at cruising rpm at highway speeds.

 

[Schurkey]

The A6 moves 42,000 BTU at 4,000 rpm. The V7 moves 47,800 btu at 4,000 rpm ... ...The BTU rating at 4,000 rpm was a common point for GM to rate the maximum continuous operation of their compressors.

I presume that's compressor RPM, not engine RPM. The compressor would be over-driven based on pulley ratio between crankshaft pulley and compressor pulley.

 

[L31MaxExpress]

I presume that's compressor RPM, not engine RPM. The compressor would be over-driven based on pulley ratio between crankshaft pulley and compressor pulley.

Compressor RPM

 

[Wildblue19]

V7 installed, not charged or tested yet. Radial bolt pattern spacing is not the same vs the R4, but the aluminum serpentine mount is easily filed to egg the holes about 3/8 of an inch to get it to fit.

It's a bit ugly, but if you wanted to convert back to R4 or Sanden it's not enough lost material to make it a permanent, one way mod if you add some washers.

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Proper belt spacing was attained with a 3/8" shim behind the 3 V7 bolt pads.

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The last mod to the OE R4 mount was a slight amount of filing to widen the space between the rear mounting flange bolts. You can see where the V7 body/case gets narrower, that the fit is tight. I moved about 1/8" off each side the get clearance for the compressor.

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Belt PN is pictured for the slightly longer than stock belt needed. The washer stack for a spacer will be replaced with solid aluminum spacers.

Hard part now is getting custom lines made and fitted to the compressor.