AC Compressor for my 1991

Does anyone know if the Denso 471-1174 AC Compressor with clutch that's for 94+ will fit on my 1991 with the newer freon conversion already done?
Thanks!

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So now I'm a little confused. Looks like Denso 471-0355 works too? That's the part number on Rock Auto. But when you search for the NSX OEM Part number, it comes up with Denso 471-1174???

Need to replace my 1991 that already has R134 conversion.

The Rock Auto part at https://www.rockauto.com/en/moreinfo.php?pk=3906252&cc=1000865&jnid=365&jpid=0 is Denso 471-0355

But when I do a search for 38810-P9k-E01, all of the Denso Results are 471-1174??
Thanks

bonhamsurf said:

So now I'm a little confused. Looks like Denso 471-0355 works too? That's the part number on Rock Auto. But when you search for the NSX OEM Part number, it comes up with Denso 471-1174???

Need to replace my 1991 that already has R134 conversion.

The Rock Auto part at https://www.rockauto.com/en/moreinfo.php?pk=3906252&cc=1000865&jnid=365&jpid=0 is Denso 471-0355

But when I do a search for 38810-P9k-E01, all of the Denso Results are 471-1174??
Thanks

Click to expand...

I'm interested to know this as well. I have a 1992, and the compressor is going out.

bonhamsurf said:

So now I'm a little confused. Looks like Denso 471-0355 works too? That's the part number on Rock Auto. But when you search for the NSX OEM Part number, it comes up with Denso 471-1174???

Need to replace my 1991 that already has R134 conversion.

The Rock Auto part at https://www.rockauto.com/en/moreinfo.php?pk=3906252&cc=1000865&jnid=365&jpid=0 is Denso 471-0355

But when I do a search for 38810-P9k-E01, all of the Denso Results are 471-1174??
Thanks

Click to expand...

DKG said:

I'm interested to know this as well. I have a 1992, and the compressor is going out.

Click to expand...

Here is the cliff notes version, based on Kaz's research:

If your 91-92 NSX is still using R12 refrigerant:

471-1424

If you have a 91-96 NSX and it has been converted to R134a refrigerant:

471-1194 (need to use smaller belt due to incorrect pulley diameter, or transfer old pulley to new compressor)

If you have a 97+ NSX and it uses R134a refrigerant:

471-1193

The 1193 compressor has the correct pulley diameter, but you need to use the 97+ mounting bracket to get it to line up with the drive pulley.

Honcho said:

Here is the cliff notes version, based on Kaz's research:

If your 91-92 NSX is still using R12 refrigerant:

471-1424

If you have a 91-96 NSX and it has been converted to R134a refrigerant:

471-1194 (need to use smaller belt due to incorrect pulley diameter, or transfer old pulley to new compressor)

If you have a 97+ NSX and it uses R134a refrigerant:

471-1193

The 1193 compressor has the correct pulley diameter, but you need to use the 97+ mounting bracket to get it to line up with the drive pulley.

Click to expand...

This is all very correct.
There are only these 3 Denso ones
1424 (91/91, it is R12 ready but can me swapped to R134 easily)
1194 (93+)
1193 (97+)

I ordered the 1424 and 1194 from Amazon knowing I'd return one for a refund.
Although my system is already converted to R134, I used the 471-1424. I simply had the AC guy switch the oil inside it to R134 BEFORE I installed it. Otherwise it was ready to go.
Chose this because it already had the same size pulley/clutch/etc and bracket. So I didn't have to reuse any old parts.
Why go through this process and not use a whole brand new setup?

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bonhamsurf said:

This is all very correct.
There are only these 3 Denso ones
1424 (91/91, it is R12 ready but can me swapped to R134 easily)
1194 (93+)
1193 (97+)

I ordered the 1424 and 1194 from Amazon knowing I'd return one for a refund.
Although my system is already converted to R134, I used the 471-1424. I simply had the AC guy switch the oil inside it to R134 BEFORE I installed it. Otherwise it was ready to go.
Chose this because it already had the same size pulley/clutch/etc and bracket. So I didn't have to reuse any old parts.
Why go through this process and not use a whole brand new setup?

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Click to expand...

Smart move for sure. In my case, I'm going to get the 1193 and the 97+ bracket for the same reason. Why re-use old parts?

Honcho said:

Smart move for sure. In my case, I'm going to get the 1193 and the 97+ bracket for the same reason. Why re-use old parts?

Click to expand...

If I didn't have a time issue to get mine done I would have probably ordered the 1193 and done the same thing. Honestly it's all the same compressor on all 3 models

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In case someone visits this thread in the future, the difference among the aftermarket compressor + CL set, etc;
http://www.nsxprime.com/forum/showt...-newer/page2?p=1996629&viewfull=1#post1996629

And the bracket offset;
http://www.nsxprime.com/forum/showt...-newer/page2?p=1996800&viewfull=1#post1996800


Kaz

A few things:
R-134a operates at a higher temp, which is likely the reason for the larger diameter pulley.
The smaller R-12 pulley running R-134a will put a tad more pressure on the system as a whole. It probably doesn't matter, but I prefer anything to keep the evaporator from a potential leak.

Don't wait for your "compressor to go", replace it before it grenades and contaminates the system. The NSX offers a miserable and expensive experience when clearing out debris and/or replacing the evaporator.


The Denso 10PA compressor is the same and used by just about every manufacturer on the planet. The NSX calls for 10PA15c. The 10PA20c has higher capacity and is a drop in upgrade (at the expense of extra drag over the 15c). Way back when Mark Basch told me that he used the Legend compressor to combat AZ temperatures; I didn't inquire on the clutch pulley size/offset.

Aftermarket parts may not be OEM and may be inferior to when compared to your original parts. So keep your old parts, they are proven quality. Even OEM replacement may not be as high spec as that originally supplied on your vehicle. I would keep your old compressor and clutch. They can be easily rebuilt with quality parts.

It appears that the NSX idler and the drive belt is the same size for ALL NSXs, so I suspect that different clutch size pulleys are effectively interchangeable. (? Kaz)


FWIW: I have an MVAC license. I don't even pretend to compete with Kaz, he has forgotten more than I will ever know.

This is all great information, thank you guys!

To clarify for my 1992 134a, it would be perfect if they sell a 1193 that comes with 1424's pulley assembly. correct?

MrHugo said:

To clarify for my 1992 134a, it would be perfect if they sell a 1193 that comes with 1424's pulley assembly. correct?

Click to expand...

Correct, but they don't. So, if you choose to buy the 1193, you either need to swap your pulley from your old compressor to the 1193 (pretty easy), use a smaller belt, or get the 97+ compressor bracket that fits on the engine block.

Honcho said:

Correct, but they don't. So, if you choose to buy the 1193, you either need to swap your pulley from your old compressor to the 1193 (pretty easy), use a smaller belt, or get the 97+ compressor bracket that fits on the engine block.

Click to expand...

Thanks for the quick reply. Have you change out all the o-rings before? How hard is it if I don't plan on taking off my bumper. I plan install new denso compressor, new all the (13 total??) x o rings, new receiver/driers, keep the old condensers, and evacuate and refill with 134a.

MrHugo said:

Thanks for the quick reply. Have you change out all the o-rings before? How hard is it if I don't plan on taking off my bumper. I plan install new denso compressor, new all the (13 total??) x o rings, new receiver/driers, keep the old condensers, and evacuate and refill with 134a.

Click to expand...

It's doable without taking apart the car. You have 2 o-rings at each condenser, 2 at the drier, 2 at the evap on the firewall, 1 near the front of the center tunnel, 2 at the front engine firewall (for the two rigid compressor hoses), then 2 at the compressor (other side of the compressor rigid hoses) and the big octagon gasket at the compressor body.

You may want to check your evaporator for leaks before going to all this trouble. It's a notorious source of slow leaks, especially on the older cars.

Honcho said:

It's doable without taking apart the car. You have 2 o-rings at each condenser, 2 at the drier, 2 at the evap on the firewall, 1 near the front of the center tunnel, 2 at the front engine firewall (for the two rigid compressor hoses), then 2 at the compressor (other side of the compressor rigid hoses) and the big octagon gasket at the compressor body.

You may want to check your evaporator for leaks before going to all this trouble. It's a notorious source of slow leaks, especially on the older cars.

Click to expand...

Isn't the Evaporator behind the firewall that requires removal of the dash? I will see if there is leak there.

Is it common that people who converted their car from R12 to 134a do not replace the oil in their compressor? Does replacing that oil important?

I'm an old MVAC. I don't replace seasoned o-rings that are impregnated with oil, they tend to hold the r-134a just fine. Change whatever o-rings that you can easily or known to leak.

You need to make sure the new compressor oil is compatible with mineral oil.

if your compressor is out, then you will have to check for "black death"...which would require a complete flush.

MrHugo said:

Isn't the Evaporator behind the firewall that requires removal of the dash? I will see if there is leak there.

Is it common that people who converted their car from R12 to 134a do not replace the oil in their compressor? Does replacing that oil important?

Click to expand...

The evap is behind the firewall inside the HVAC unit. Because of the design and the way it sits in the unit, over a long period of time, vibrations will cause hairline cracks in the piping. It's a fairly common issue on the older NSXs and most will eventually develop a leak. The tell tale sign of a leak is that, over time, you will see a film start to build up on the inside of your windshield near the defroster vent. You can inspect the evap (somewhat) by removing the blower unit in the front bay- no need to pull the dash. I would have an A/C shop run the leak dye and then pull the blower to see if there is dye on the evap unit. I would hate to see you go through all the trouble of a R134 conversion only to have it all leak out of your evap and be back at square one.



All of the R12 oil should be evacuated from the system and replaced with a R134 compatible oil. R134 native systems use PAG oil (the Denso 1193 compressor comes pre-filled with PAG). I believe the R12 conversion process uses esther oil, since it is compatible with R12 and will not ruin any seals that have been exposed to R12 that are left in the car. If you choose to use PAG oil, you generally must flush all of the A/C lines with an A/C flushing solution to make sure no mineral oil is left in the system.

drew said:

I'm an old MVAC. I don't replace seasoned o-rings that are impregnated with oil, they tend to hold the r-134a just fine. Change whatever o-rings that you can easily or known to leak.

You need to make sure the new compressor oil is compatible with mineral oil.

if your compressor is out, then you will have to check for "black death"...which would require a complete flush.

Click to expand...

This is what LarryB always recommended. He only replaced O-rings that were disturbed and left the other ones alone.