930 Turbo - Lets Drop the Motor and Tear it Down!

[Jason Cullen]

Pelicans:

Today is day one of my 3.3 Turbo motor project!

With a little help from my Friends: Tom Amon and Jimmy Deering!

The "To Do" list is gargantuan.

The finished motor will have:

MSD Ignition

964 Cams

89 Turbo "Stock" exhaust system, stock K-26 Turbo with a 1 bar Spring

3.2 Carrera Tentioners w/Guards

Complete Re-Build, in short!

The 3.3 is fitted to a rebuilt 915, which drastically reduces “Turbo Lag”! This enables the 3.3 to out perform the standard 4-speed 930’s. It also makes City driving manageable. I forfeit total Top End Speed for extremely fast lows and mids.

I will update this post as progress or changes to the motor modifications continues!

[Jason Cullen]

[ianc]

Looks good! No room in the shop?

ianc

[slow&rusty]

Very cool pics! Enjoyed them, looking forward to more updates.

Hope to hear more about the rebuild. How many miles were on that motor? How long did it take you to drop the motor and transaxle?

Yasin

[TurboRuf]

Jason,

Thanks for sharing! I've been waiting for a 930 tear down thread. Please keep us posted on your progress.

[Jason Cullen]

Yasis,

About 80k on the motor.

It took an hour to have the motor and trans completely dropped.

To full disassemble the entire motor took about 6 hours.

Ian - I am always pressed for space!

Thank you,
Jason

[jkarolyi]

Cool project. Can a 915 be built at a reasonable cost to withstand the torque of a 930? There's a reason why Porsche put those heavy duty 4-speeds in there.

[beepbeep]

Sorry if I'm nitpicking but a 930 is always a Turbo. There are no
naturally aspirated 930 cars..."930" is designation for 911 Turbo (first
generation). So it's either 911 Turbo or 930

Second, KKK K26 is not found on any 911. It's stock on 944 Turbo. 930 has
either KKK 3DLZ (which your car probably has, being made 82') or KKK K27
(later cars).

Third: 915 tranny is not going to "drastically reduce Turbo Lag"...it's
nothing more than transmission with shorter gears. Your engine will still have exactly same boost treshold as before, but you'll have more tightly stacked gears. Also, your car is 82' and
thus has long clutch housing, which means your engine sits further back than
with 75-77 930 and SC. So installing 915 transmission is not a simple
"drop-in" as you have to fabricate new tranny- and possibly engine mounts
and replace shifter column. At last, there are reliability issues...there
are good resons why PAG developed 930 transmission instead of just fitting
915 gearbox into 930 car. 915 are somewhat fragile.

Forth: fitting 1-bar boost spring is a crude way of raising boost. It
demands dissassembly of wastegate (which is not so trivial as it seems).
It won't allow you to lower the boost either in case your engine starts to
ping or you run on bad batch of gas. Installing a T-orifice, Dawes device
or electronic boost controller is better way of dialing the boost.

So I would recomend you to keep your transmission and boost spring stock.
MSD ignition with dual plugs would be a good upgrade though.

Reduction of turbo lag can be done by using modern turbocharger (Garrett GT35R etc.) together with short headers with heat-wrap. EFI and dual turbochargers will shorten the lag even more.

Good luck!

[RideShoot&Drink]

I have my beer and snacks ready to enjoy the show...good luck with the project and please update us with results.

[Emission]

Originally posted by beepbeep
Sorry if I'm nitpicking but a 930 is always a Turbo. There are no
naturally aspirated 930 cars..."930" is designation for 911 Turbo (first
generation). So it's either 911 Turbo or 930

Second, KKK K26 is not found on any 911. It's stock on 944 Turbo. 930 has
either KKK 3DLZ (which your car probably has, being made 82') or KKK K27
(later cars).

Third: 915 tranny is not going to "drastically reduce Turbo Lag"...it's
nothing more than transmission with shorter gears. Your engine will still have exactly same boost treshold as before, but you'll have more tightly stacked gears. Also, your car is 82' and
thus has long clutch housing, which means your engine sits further back than
with 75-77 930 and SC. So installing 915 transmission is not a simple
"drop-in" as you have to fabricate new tranny- and possibly engine mounts
and replace shifter column. At last, there are reliability issues...there
are good resons why PAG developed 930 transmission instead of just fitting
915 gearbox into 930 car. 915 are somewhat fragile.

Forth: fitting 1-bar boost spring is a crude way of raising boost. It
demands dissassembly of wastegate (which is not so trivial as it seems).
It won't allow you to lower the boost either in case your engine starts to
ping or you run on bad batch of gas. Installing a T-orifice, Dawes device
or electronic boost controller is better way of dialing the boost.

So I would recomend you to keep your transmission and boost spring stock.
MSD ignition with dual plugs would be a good upgrade though.

Reduction of turbo lag can be done by using modern turbocharger (Garrett GT35R etc.) together with short headers with heat-wrap. EFI and dual turbochargers will shorten the lag even more.

Good luck!

Nice post with some good advice.

Jason - Keep those pics coming. Great thread!

[Jason Cullen]

beepbeep,

Well to be absolutely correct – In 1982 it’s a “911SC Turbo”. Grey Market 930.

915 Gear Box? On the contrary! The shorter gears in a 915 Transmission allow
a “Kick Start” up in the Rev’s. I can hit 3k RPM range is a fraction of that of a long gear ration 930 box. So – I disagree. I’ve driven both and the 915 outperforms the 930 box 0 to 125 MPH. The 930 Box does outperform the “Top End Speed” significantly.

I’ll take the 915 any day over a “Long Gear Ration” short bell housing 930 Box.

My Tech has performed over a dozen of the 915 conversions for the 3.3’s – Absolutely wonderful upgrade. Yes- they do require some modification and the boxes are built with fresh carrier bearings and forward pinion bearings to with stand the torque.

A KKK 26 and a KKK 3DLZ is the same Turbo Charger.

I appreciate your “Knit Picking” and value some great pointers!

This is project is basically stock with a few “Bang For your Buck” upgrades.

Thank you,
Jason

[Jason Cullen]

Noah,

Candy Apple Green!

Can't wait to see your car back on the road!

Thank you,
Jason

[Jason Cullen]

Today is "Parts Cleaning Day"! Fun, Fun and More Fun!

The Crank and the Head's just hit the machine shop!

Jason

[hobieboy]

I'm with Goran on the 915 from the reliability point of view...
Two instructors I know had 915 on their turbo. Both had way >300hp. Both blew the 3rd gear - yes, the gear shattered, on the same day, on the same track.
Another instructor with a 73 RSR clone with ~350hp and 915. The box is rebuilt, pretty much every 2 seasons.
So I tend to think the 915 can probably support close to 300hp but if you have anything a lot more than that, it will break quite fast.
Depending on your use, re-gearing the 930 box can make it a very good tranny.

[beepbeep]

Originally posted by Jason Cullen
beepbeep,

Well to be absolutely correct – In 1982 it’s a “911SC Turbo”. Grey Market 930.

930 is Porsche's internal code for 911 Turbo. No SC there.

915 Gear Box? On the contrary! The shorter gears in a 915 Transmission allow
a “Kick Start” up in the Rev’s.

...1:st gear of 915 tranny is so short that you sweep out of rev-range before motor starts developing any significant boost. Even if 915 box will allow you to keep engine in upper portion of rev-band, I see it as a downgrade. 1:st gear is too short for anything else but starting from dead-stop and case/gears are too weak to support any serious motoring.

Remember, it's torque not power that kills transmission. Turbocharged engines unfortunately develop much more torque than it's N/A counterparts so I see 915 as a bad idea. If you don't mind loosing top end, I believe that changing 930 R&P to shorter one is much better upgrade.

A KKK 26 and a KKK 3DLZ is the same Turbo Charger.

No they are not. KKK K26 is a smaller unit used in Porsche 944 Turbo and Audi 200 Quattro Turbo. 3DLZ is approximately same size as KKK K27.

Cheers.

[Jason Cullen]

Goran,

You are approved to join the project! When am I picking you up at the airport?

It's ok to disagree. I understand your point of view on the 915 gear box.

I happen to trust the 35 years experience of Tom Amom who is "Lead" on this entire project. He properly builds the 915 to withstand the torque and has built / Modified over a dozen 930's with 915 transmissions.

I appreciate your energy and input!

This goal for this thread is to share the experience of this project.

Also - get the 930 back on the road!

Thank you,
Jason

[MobileWrks]

It was very cool to help out with this car. The weather was nice... just as we were done, drizzle just started to come in aswell as the clouds..
i try not to smile, but Tom and Jason will ride my ass... sorry for the one half smerk!!!!
Nice Pics Jason....

[alwaysflat6s]

Jason,
It is always great to see someone tackling their own work on a 930.

I don't want to sound like I am picking on you and I do agree with some of your ideas but you need to slow down and consider a few things as you are doing this. I am telling you as someone who has owned 930s since the 80s and am now on my 6th. I also have an extra project engine sitting around. They are lots of fun to play with but they are serious fun and taking cheap short cuts invariably leads to expensive disasters.

I URGE you to PORT out those heads while you have things ripped apart. It is also inexpensive to have the heads drilled for twin plug at the same time. All you do is put a spark plug in until you are someday ready to twin plug it. The porting will not make much difference with that lousy tubo unit but I would presume in the future you will carefully pick a better unit. The K26 was an antique even when Porsche started using them. A good K27 11/11 or carefully chosen compact K29 will do wonders-but cost you. I have to agree that modding that stock K26 is NOT a good idea. Wait till you can afford a better turbocharger and play with that. With summer heat and a constant 1 bar you could discover your pistons have eaten themselves alive. I have a box of beautiful 930 pist/cly sitting around. One of them is destroyed.... Ask me how I know...

The 915 is a good temporary fix for the horribly stock 930 gearset. For those that do not understand, the stock 4 speed has gears so widely spaced that you find yourself all the time in situations where there simply is no "correct" gear for the machine to work well. So, for the time being, good. B.A. used to say that the change felt like an extra 100HP- I agree. However you ABSOLUTELY MUST NOT nail it while crusing along in 5th gear! ABSOLUTELY. This will burn up your 5th gearset so fast it will make your head spin. If you want to GO, downshift into 4th. Always. Also, the advice about blowing up 3rd gear is accurate. I had a box gone through and did every modification know to man. It had not been abused and had about 3k on a complete rebuild. I had a friend who really wanted
to build a replcia of my box. I happened on a $$$ Ruf 5 speed and bought that and made a good deal for my friend. It seemed like a good deal for him the box blew apart and took out most of everything. Had he been nailing it on some badk road when this happened it could have made for a really bad accident. I once had the experience of rolling 4 times...uphill.. at Sears Point when a gearbox box broke at a critical moment... the rough part was when it proceeded to roll over and over--back down that hill and came to rest right on the racing line facing traffic! So, think about this as I promise you the 915 WILL fail if you use it long enough, and a lot sooner if you use it agressively. Meanwhile, with some prudence it will liet you enjoy that car enormously more than you have been able to. But it is not a long term conversion. Using the correct synthetic lube will help it but it still will not change the torque load you are putting through that 915.

Now I could says RACEWEAR is also essential and someday you really should do that. But the list is endless and I suspect you are not plannign on spending $20k+ upgrading it. And, yes, you can easily spend that on just the engine.

Good luck and have fun.