GM R4 Compressor - New Scroll Design. Better than Piston Type ?

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waid1017
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GM R4 Compressor - New Scroll Design. Better than Piston Type ?

Postby waid1017 » Thu Aug 24, 2017 8:57 am

While looking for a new R4 Compressor, I found an aftermarket company making a new GM R4 but in a Scroll design! No Pistons. I would think the Scroll type with less moving part would me more reliable. They are on eBay and Amazon. The pulley is smaller than typical R4 use spin the Scroll faster I assume.

I do find it very interesting that this company went out of the way and decided to re-engineer the R4 instead of cloning it. See the back picture of the compressor. It appears that it is a small scroll housed in same case. I am sure there are no large o-ring under the black steel case which has been leak issues with the original R4.

This eBay listing clearly states its a Scroll. If you look at the inner Aluminum Case, it is completely different. It does not have the 4 bolts that holds the front cover.

http://www.ebay.com/itm/351947764990?rmvSB=true

Anyone have any experience with this?

Thanks
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bohica2xo
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Re: GM R4 Compressor - New Scroll Design. Better than Piston Type ?

Postby bohica2xo » Thu Aug 24, 2017 11:17 am

Looks like a Trash-90 crammed in an R4 can with a fresh casting.

Pulley looks to be the same size as an R4 - care to give us an actual measurement?

Since you seem to have pics that are not on the e-bay link you posted, are you selling this product?

"Better than piston type?" Better at what? A performance curve would be the only answer.
waid1017
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Re: GM R4 Compressor - New Scroll Design. Better than Piston Type ?

Postby waid1017 » Thu Aug 24, 2017 12:07 pm

What is the Trash-90 ?

I have unique application. I am installing AC in my 1964 Falcon using Explorer 5.0 timing cover and short water pump so need a very short AC Compressor and the R4 fits the bill. I have a bad R4 that I used for mock up. I made my own brackets and spacer and R4 fits really nice. I have not found any AC compressor that is shorter than the R4. No not selling anything. Just looking for something little better as most people says that R4 is not a good compressor. From the reviews on Amazon, the pulley is actually smaller than typical R4.

Pictures are on Amazon:

https://www.amazon.com/Premium-Quality-Compressor-Clutch-Vehicles/dp/B00JXZJ9FK

https://www.amazon.com/Compressor-Clutch-Complete-Repair-Trucks/dp/B00JXYEU78/ref=pd_rhf_dp_p_img_9?_encoding=UTF8&psc=1&refRID=RQEFCTXASH7HHPHFA9S0
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Tim
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Re: GM R4 Compressor - New Scroll Design. Better than Piston Type ?

Postby Tim » Thu Aug 24, 2017 3:26 pm

Maybe I'm missing it but looks like a normal UAC R4 to me.

I'll let it slide but normally do not allow eBay links on this forum. Never know the sources or why someone is pushing a product. Especially with 2 posts.
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71403
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Re: GM R4 Compressor - New Scroll Design. Better than Piston Type ?

Postby 71403 » Thu Aug 24, 2017 5:21 pm

Understand your issue with fitment and existing work (and nice work, btw) on brackets but an R4 is the last compressor I'd ever retrofit to something.

Few weeks ago asked a supplier for performance chart/curve of an "R4 scroll" compressors and they couldn't produce one - without that impossible to say how it will work. If an R4 job comes around I'd have to try one just to kill the curiosity, so I say "go for it" and report back....
GM Tech
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Re: GM R4 Compressor - New Scroll Design. Better than Piston Type ?

Postby GM Tech » Thu Aug 24, 2017 6:38 pm

Every scroll I have run or seen on current vehicles have a need for speed- every one of their owners complain of no cooling at idle. Suction pressure is in the 60s at idle- will drop to 30s at 3500 erpm.
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Re: GM R4 Compressor - New Scroll Design. Better than Piston Type ?

Postby Dougflas » Thu Aug 24, 2017 8:41 pm

GM Tech wrote:Every scroll I have run or seen on current vehicles have a need for speed- every one of their owners complain of no cooling at idle. Suction pressure is in the 60s at idle- will drop to 30s at 3500 erpm.



Wouldn't the fact that the pulley on the scroll is smaller eliminate the high rpm requirement?
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bohica2xo
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Re: GM R4 Compressor - New Scroll Design. Better than Piston Type ?

Postby bohica2xo » Thu Aug 24, 2017 11:36 pm

The pulley on that scroll /R4 is the same size as a stock R4 - compare the pulley OD to the mounting holes in the case.

The R4 is short. There is not enough room to put a TRS105 in it's place. So the more likely thing is a new outside case for a TRS90 to mount it in the old R4 can.

A TRS90 (or even a 105) would need a 50mm diameter belt pulley to spin fast enough to come close to the output of an R4.

As ice already pointed out in the other thread the TRS105 was a dismal failure in the Trailblazer.

Technically the HR980 compressor (Ford YC-177 1983-88 Mustang) is probably more compact - and possibly a worse choice than an R4

I would pick up a V5 or V7 core & start on a new mount.

.
waid1017
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Re: GM R4 Compressor - New Scroll Design. Better than Piston Type ?

Postby waid1017 » Fri Aug 25, 2017 10:03 am

71403 wrote:... R4 is the last compressor I'd ever retrofit to something.


Pricey the reason why I posted here since all I hear is that R4 is junk.

Guys my 1964 Ford Falcon is not a daily driver. Just once or twice a month weekend cruiser. It would be nice to have little bit of AC when it's 90 outside. I have attached a pic of the 18x16 condenser that I am planning to use that will fit my car. Also is the picture of the Universal Under Dash AC Evaporator which has 32 Pass 4-way evaporator coil, Max Air Vol.: (390 CFM), Cooling Capacity: (3300 Kcal./H).

If you read the reviews on Amazon for Scroll R4, the pulley is smaller than the normal R4. Here is what this guy said:

Edited Moderator

Everything bolted together as expected. It was a little ...
Bybobbyon August 30, 2016
Verified Purchase
Everything bolted together as expected. It was a little tough to get the old compressor off but that is just the design of the engine. The reason i took off 1 star is because the original belt would not fit back on, it was too loose. I think this is due to the difference in the diameter of the wheel on this compressor vs the original one. The difference was too much for just adjusting the tensioner pulley. I dont have the exact part number handy but ended up having to get a serpentine belt that was about an inch shorter. This was on a 1994 chevy 1500 5.7 V8.
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Tim
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Re: GM R4 Compressor - New Scroll Design. Better than Piston Type ?

Postby Tim » Fri Aug 25, 2017 10:12 am

How many times are you going to post a like to the product?
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