Question on SN89 paxton

[MY 93 GT]

I had an SN93 what is the difference and is this one better then the sn93 what type of boost can i get from this model...Thanks.,

[Michael]

I had an SN93 what is the difference and is this one better then the sn93 what type of boost can i get from this model...Thanks.,

You're asking if the SN93 you had is better than the SN93? Unless one has had significant modifications made to it, their exactly the same blower.

As for boost, that depends. With a stock impeller, expect about 5psi - 5.5psi. With a H.O. impeller you'll see about 6psi - 6.5psi. You might get a bit more boost if you spin the supercharger faster, but you wouldn't want to spin it any faster than it's designed maximum rpm (which I believe is about 39,000 rpm).

[MY 93 GT]

You're asking if the SN93 you had is better than the SN93? Unless one has had significant modifications made to it, their exactly the same blower.

As for boost, that depends. With a stock impeller, expect about 5psi - 5.5psi. With a H.O. impeller you'll see about 6psi - 6.5psi. You might get a bit more boost if you spin the supercharger faster, but you wouldn't want to spin it any faster than it's designed maximum rpm (which I believe is about 39,000 rpm).

I worded it wrong..lol..I had an SN93 [sold it] now i have a chance to buy an sn89 what is the difference from one to the other and which one was better?....How much boost will i see from an SN89 ?.......thanks sorry about the confussion....

[Michael]

The SN93 and SN89 are virtually identical, except for the identification label. One isn't "better" than the other; one is just chronologically older.

And the boost numbers in my post above apply to the SN89 as well as the SN93. In fact, they apply to virtually all Paxton 'SN' superchargers (SN60, SN89, SN93, & SN2000).

[MY 93 GT]

The SN93 and SN89 are virtually identical, except for the identification label. One isn't "better" than the other; one is just chronologically older.

And the boost numbers in my post above apply to the SN89 as well as the SN93. In fact, they apply to virtually all Paxton 'SN' superchargers (SN60, SN89, SN93, & SN2000).

Thanks which one is the older one the SN89 ? im guessing?.....

[Michael]

Yes, the SN89 is the older of the two.

[MY 93 GT]

Yes, the SN89 is the older of the two.

Thank you!!!!

[whodwho]

The SN93 and SN89 are virtually identical, except for the identification label. One isn't "better" than the other; one is just chronologically older.

And the boost numbers in my post above apply to the SN89 as well as the SN93. In fact, they apply to virtually all Paxton 'SN' superchargers (SN60, SN89, SN93, & SN2000).

The SN93 had the 6 thru bolts around the center ball drive support, that should be a better design in keeping a more consistent ball pressure?

I have both and I am assuming the SN93 is a better of the two and plan on keeping it out of the two?

Looks like they had changed it up again with the SN2000/GSS.

[Michael]

I have an SN89, and to be honest, I don't remember how many bolts it has around the central ball drive. I thought it was six bolts, but I could be wrong... it's been a long time since I opened up the head unit.

However, from all the research I've done on the subject of the SN everything has stated that all the SN units (with the exception of the GSS) are virtually identical, with only very minor changes to the internals focused on improving overall reliability. However, I don't know what those changes were (ie. oil seals, oil pump design, bearing/races material, etc...). That's not to say that an older SN (ie. an SN60) isn't as good as a newer unit (ie. SN93); I don't think the reliability improved drastically with these minor changes.

[whodwho]

I would say these were a fairly significant design change most likely to help with the additional bearing pre load to keep from slipping from the additional load of spinning faster, modified impellers and the extra load of the VR4 upgrades.

These are the changes I was referring around securing core of the ball drive support, the earlier ones were just bolted together with the outer case bolts. The SN93 started with the 6 large thru bolts and the GSS/SN2000 ditched the large thru bolts and had an internal plate to secure the ball drive assembly.

I tried to dig up a few pics for reference


Pre SN93




The SN93 thru bolts(need to find a disassembled pic)



The later GSS/SN2000 with the plate

[Michael]

So ultimately, the primary changes in design between these SN's were made to place more pressure on the drive balls.

To be honest, I didn't realize there were these differences between the SN89, SN93, and SN2000. Great info - thanks for setting the record straight (at least, for me).

However, I think it's still safe to say that the output (boost) of these units didn't change from one to the other. The impeller and scroll design was identical between all these units (except for maybe the GSS and definitely for the VR4); the five-ball drive system (and corresponding 4.44:1 drive ratio) was the same for all SN's. I believe the maximum intended impeller speed was 39,000-40,000 RPM for all SN's as well. So to say the OP can expect between 5psi-5.5psi from a stock impeller equipped SN, or 6psi-6.5psi from an HO impeller equipped SN isn't wrong... is it?

[whodwho]

Oh not at all sorry if sounded that way, I was just commenting on the differences of the models. :)

I have been running a SN89 and had picked up a SN93 and noticed the differences so had been poking about to see if the newer design was better as I was confused by the lack of the big 6 bolts of the post SN93s and thought they might of gone back to the old method and then had seen the addition of the plate design.

There are hints of the differences posted here and there but it is not real obvious until you see them side by side so thought I would share some of my findings, and everyone loves looking at pics! :D

[pavement pounde]

Hey, that thirth picture is mine ;)
I got a bunch of SN93 pictures if you like.

[whodwho]

Hey, that thirth picture is mine ;)
I got a bunch of SN93 pictures if you like.

Yes it is, was hoping you didn't mind as they were posted on this site already, I stumbled across a couple and I went for the album but it was set private!! :)

Thanks for the pics, it is interesting to see the internal changes as there were so few external ones.

[MY 93 GT]

Thanks guys for the great info :D...So if i can pick this SN89 up for my 87 GT for about $800 complete and it is in good working condition is that a fair price? Also if i get 5-5.5 psi i should get around 75 hp more out of my 5.0 ? so i might see around 275 to the rear wheels? I do have Headers,off road H-pipe..Flowmaster cat back.70mm TB, basically thats it stock mostly...it has anAOD with an awesoem shift kit and im going with 3.55's Im hoping for mid to low 13's is it possible?