GregBBRD

Just a passing thought:

Because Porsche needed more alternator output for the later cars that didn't turn very many rpms (non 5 speed cars), they made the drive pulley larger (which requires a longer belt) on the late S4 and GTS vehicles equipped with an automatic transmission.

Of course, the larger pulley used more horsepower to spin the alternator faster...

The early cars all used drive pulley 928 102 139 11, which is 5.160".

Late S4 ('90 and '91) automatics and GTS automatics all used 928 102 139 12, which is 5.480".

If you are using my new high output alternators on one of these late automatics, it's so efficient at lower rpms that you don't need to spin it faster....so keep your eyes open for the smaller diameter pulley and swap it, next belt change.

"Free horsepower"!

Of course, the inverse is also true. If you have an early car and you don't buy my high output alternator, keep your eyes open and find the larger diameter pulley (especially if you have an 1985-1989 automatic).

I can envision some pulley trading coming on....

the flyin' scotsman

its alive!!!

My garage isnt heated so shall wait for warmer temps to install; what a beauty.......thanks Greg, Mary and team.

I should have ordered a second

GregBBRD

Conveniently, I'm honoring the special price until Friday.....

jcorenman

Jeez, another variable ... So our '90GT should have the smaller pulley, correct? How are you measuring? Outer rim, or top of the grooves, or bottom? Ours measures approx 5.388 OD at the outer rim...

GregBBRD

Yes, you should have the smaller version. Only the automatics got the bigger version....supposedly.

Pretty easy to tell by the different belts. We sent you a short belt. If you had the bigger drive pulley, you would have never gotten the belt on.

Porsche did some sneaky things....both with this pulley and the A/C drive pulley.

I'm measuring to the top of the grooves, BTW. Your outer rim measurement is correct for the smaller pulley.

jcorenman

Yep, belt went on, easily. Thanks!

Red Flash

OK, so that means that earlier cars and GTs used the smaller pullies, correct?

GregBBRD

Yes. Only one (small) pulley until 1990.

the flyin' scotsman

Fantastic news

Taguid

Wow! My dash gauge is now at 13.8. It has always been near 12.6 in the past. Great product GB.

Hilton

I haven't heard back yet - does that just mean you're still catching up with vacation email backlog and shop work?

I'm in no rush, just want to make sure my email didn't slip through the cracks

I sent it to the one in your sig on the first post Greg - was that the right address?

gregbbrd@aol.com

Cheers!

GregBBRD

Mary is working on shipping. I'm pretty sure the quantity of orders has her overwhelmed....it takes a long time to make each box is bomb proof, bullet proof, and certified to survive a small nuclear explosion.

And there is always the chance she is waiting on another truckload of packaging tape.....

I'll check and see how she is doing and where you are, on the list.

Rob Edwards

1990 Service info tech blurb about 90+ alternator pulleys and belts, for posterity:

Hilton

I'm not fussed how soon it ships - just wanted to make sure I was on the list - email isn't a reliable communications method - between spam filtering, server outages etc.

Thanks for making it!

GregBBRD

Update:

I finished another batch of a dozen (12) alternators today, which should fill all the outstanding orders.

Mary will be shipping on Monday and Tuesday. If you haven't heard from her by Wednesday (for the final details), there's a very good chance you've been forgotten and you should contact her at 714 879 9072 or MaryBBRD@att.net.

I'd like to sincerely thank everyone who ordered or expressed interest in this product! It has been an incredible success....far beyond what I imagined. Thank you all!

From here on out, Roger at 928 R US will have inventory on these Bosch High Output Alternators.