Yet another 930 rebuild - completed
 

Many thanks to all the Pelicanites for the good advice and pictures of your rebuilds. I'm starting my 930 build. Just test fitted some parts tonight (see pics below) and I still have some more cleaning to do. The basic specs include: an Ollie's shuffle-pinned case; twin-plugged, ported, polished & flowed heads; 3.2 Carrera intake; 42# injectors; K27-7200 turbo; GoingSuperFast full-bay intercooler; B&B headers; dual 6 plug EDIS ignition; and MegaSquirt II v 3.0. I suspect it will be a month or so getting things together and tuned. So here's how it looks during the test fitting:
http://pickettweb.com/Porsche/PE%20013.jpg
http://pickettweb.com/Porsche/PE%20014.jpg
http://pickettweb.com/Porsche/PE%20058.jpg
http://pickettweb.com/Porsche/PE%20059.jpg
http://pickettweb.com/Porsche/PE%20055.jpg
http://pickettweb.com/Porsche/PE%20057.jpg
http://pickettweb.com/Porsche/PE%20054.jpg

Mike

Looks nice and purdy. What is that shrouding around the tops of each cylinder?

Those are the standard 3.3L Turbo cylinders that are not fully finned (on the top). Porsche realized their mistake and the 965 was given fully finned cylinders. On my rebuild, I've opted to go fully finned. Looks nice though.

Thanks. Figured I'd clean it up so it would transfer heat a little better. By the way, I test fitted the Magnecor wires I got from BoostEngineering and they look good! They have a great price on the 8mm blue wires. I had them make up a custom set for the twin-plugged heads.

Ahh, I see, thanks. I have never seen Porsche cylinders like that. Not sure what motivation Porsche had to do that?

Thanks for the clarification:)

I couldn't agree with you more! When I think of the countless Type1 VW engines and 356 engines that I've built over the years and they ALL had fully finned cylinders, you can imagine my surprise when a high performance, high heat engine like the 911 Turbo is missing these fins on top!!!! I've been told that Porsche thought the air generated by the fan would flow better around the cylinders without the fins!:rolleyes:

Great setup! Good luck!

I was reading the Porsche Handbook last night regarding finless cylinders - It mentions that Ruf built his own P/C (3.4L) because of this issue.

What cylinders could be used? 3L 3.2L?

Actually....there was a thread on this site about a 917 engine being rebuilt. There are some very interesting photos posted. One of them is the 12 cylinder long block showing the cylinders are half-finned, just like the 930. Porsche may have learned something from their 1000+HP monsters. ;)

Here's what I know:
-The fully finned 3.2 cylinders can be used...typically they are bored out to 98MM (3.4L) and then replated and supplied with JE 98MM pistons.
-The later style 3.3L fully finned cyliners found on the 965 (964 Turbo) can be used
-The Mahle "Ruf" 3.4L can be used
-The LN Engineering "Nickies" can be used
-JB Racing also manufactures a high-end fully finned cylinder

I just couldn't bare the thought of not doing something about it...I'm not going back into this engine ever again!

So what was your solution?

As for the OEM finless cylinders...I'm wondering if Hans (the OEM supplier) and Frans (the 930 Porsche engine engineer) made some sort of deal in the beer garden or the golf course to use these things...

What is your budget?

3.2L cylinders - approx $1500 from EBS (year ago pricing)
Nikkies - approx $2700
JB Racing - approx $2700

Couple more questions:

What are you going to do with the car?
Why did you choose 42lb injectors?
Why did you choose a K27 7200 turbo?
What max boost will you run?
What cams did you choose?

Very nice work so far. Good luck.

Ya, that's what I said too - this weekend is the third time in six months I've dropped the motor to "do something"...

I opted for 98MM JE pistons with new Nikasil 98MM cylinders from Henry Schmidt @Supertec. The price was too good to pass up. Not sure what the origin of the cylinders is (Mahle, or LN, etc), but I trust Henry. We'll see in the next couple of weeks when my order is complete...waiting for JE to do their thing.

Thanks. My budget is "fluid." :rolleyes: Originally I was shooting for around $8K but found that the crank was toast when I opened it up. I ended up buying the disassembled 930 engine that sprbxr had for sale a couple of months ago for parts. My cylinders and pistons measured out fine and I just couldn't justify new ones.

What are you going to do with the car?
- Street and pleasure driving. It is a cab and I don't plan on racing it (I've got a highly modified miata that I race). I'm looking for improved low end torque, strong top end (but not necessarily spending much time above 6000 rpm), reliability, good drivability (no idle problems) and no/few oil leaks :) ).

Why did you choose 42lb injectors?
- Looking at the rwhp that others are making with similar setups, I decided to set it up for roughly 425-450 at the crank. Using the RC Engineering calculator I decided that the 42# injectors would do the trick (especially since I'm using the Megasquirt and will have a lot of control of the duty cycles, etc). In checking other applications, it appears that I'll be able get a decent idle with the 45#'ers.

Why did you choose a K27 7200 turbo?
- Improved low end boost. I wasn't willing to spring for the HF series (although they look great).

What max boost will you run?
- Probably .8 bar. Just depends on what I see when I dyno it. With the twin-plugs and big intercooler I should be able to run more, however the heads are set up for 8:1 compression and like sand_man, I don't want to make a habit of going into the engine.

What cams did you choose?
- I'm using the 964 camshafts. I was considering the SC cams but John Dougherty says that the 964 cams give you about 25 hp over the SC cams. With the head work (increased compression) and my goal of good idle I was reluctant to go with any wilder cams.

Now if anyone has any fully finned cylinders/pistons they want to give to me before I button it up... :)

Mike

Hi Mike:

Do you know what kind of power levels you are looking for? Depending on cams, static compression, boost level and such, you might find that 42 lb/hr injectors to be small,.........:)

Bear in mind that air-cooled Turbo engines rely on the evaporative effects of fuel cooling to help maintain reasonable cylinder head temperatures and "best-power" AFR's are too lean for one of these to survive for long.

DonE asked some good questions that should be considered before making some hard decisions so you do not do this all over again. :)

Finally, Porsche's finless Turbo cylinders was the result of their efforts to try to maintain more even cylinder and ring temperatures around the circumference of the barrels when the engine was hot. Needless to say, the "experiment" didn't work as planned and most of these engines had leakdown figures that were less than ideal. This resulted in excessive blowby under boost and one noted result was engine oil that became discolored (contaminated) faster than normal.

Porsche followed Ruf's suit and corrected that with the C2 Turbo's P/C's. Thankfully, the replacement 3.3 P/C's are now fully finned for durability and longevity. :)

OK

The opinions below are based on my experience and are only here for you to consider - it seems you've put a lot of thought into this already and I am in no means questioning your logic/budget/build/etc.

Turbo - it WILL run out of breath at 5500 rpm with your new set up. I would reconsider the HF.

Cylinders - I would reconsider getting fully finned cylinders as you have quite a nice engine that will create a fair amount of heat - more than what the stock cylinders were designed to take.

Injectors - consider the Bosch 52lb injectors. Great low end and drivability because of spray pattern. Can supply up to 600 hp at the crank when you turn up the pressure.

Again, very nice and good luck.

More REALLY good advice from Don,....:) :) :)

The last thing I'd add is that I sincerely hope that this engine gets mapped on a dyno (not inertial) by experienced personnel so that you do not put all those expensive parts at risk.

Great advice, guys! I really appreciate it. I know the engine can put out more hp, but I'm going to keep the boost purposely low since this is just a "fun" car that I'm not going to race (although 600 hp would be fun to experience). Steve, great advice on the dyno mapping and I agree completely. This is too much of an investment to fry on a bad tuning guess. I have a dyno guy that I've tuned with for several years that I'll work with (I'll be shooting for 11.5-12.2 to 1 air/fuel ratios).

Having taken several engines to the ragged edge and then backed down the outputs to "sane" levels later, I'm trying to find the right balance on this one at first. I hope I'm not wrong about living with the stock 930 cylinders but I guess I'll find out. I'll keep on the lookout for fully finned cylinders for a future top end transplant.

Mike

Mike, I'm doing a very similar rebuild as yours but with a K27HF; so would be very interested in your progress; particularly the map for the MS ECU :)

DonE, any idea how does the Bosch 52lb injectors compared with the Siemens 55lb ones? Quality, injection pattern, etc.?

One question I have is: how would one estimate hp? Say with Mike's build, would one expect 400rwhp? 450rwhp? or more?

thanks...

Hobieboy,
I don't have a map for the MS yet but if I get there first I'll be glad to share. Regarding injectors, I understood that the '96-'98 turbos used 38# injectors and made 408 hp at the crank (someone check me on this if you have better info). I'm betting I'll end up with just a shade under 400 rwhp at .8 bar based on what others have made. That would be plenty for what I plan to use the car for.
Mike

I would recheck your injector sizes. At 50lb of fuel pressue you need like 58# injectors. See following links for calculators
http://www.iroczone.com/calcs/injectorsize.htm

http://www.rceng.com/technical.htm

I have 42# injectors in my BMW M635 and it only makes 300 HP, thats injector limited. fuel pressure is 48#.

I would recommend you speak to an expert about your injector question - someone like Marren Fuel Injectors for example (www.injector.com). I have 72lb Siemens injectors which are sloppy at low rpm, but 72lb is a big injector for a 500rwhp motor.

As for estimating Mike's hp, I would estimate a low of 365 and a high of 390 rwhp. Why? Small injectors, .8 bar boost, K27 (small turbo), 964 cams. It's my opinion (please, no offense Mike) the engine is a bit mis-matched, even for a mild turbo car.

None taken whatsoever. I'll look into upsizing the injectors. DonE, Snowman - I appreciate the links to the calculators! By the way, does anyone have a part recommendation for replacing the throttle position switch on the Carerra 3.2 intake with a full potentiometer TPS (for the Megasquirt EFI)?

Thanks,
Mike

Mike, would really appreciate if you can share your map later on :) I've just disassmebled my engine and the rebuild part will start probably in another week or 2.

BTW - why do you need a TPS? With MS, I'm planning on using only MAP and RPM for fuel calculation?

I also agree with DonE - you should consider a better turbo like the K27HF.

DonE - thanks for the suggestion. Will give them a call. I sent an email to RC Engineering but nobody replies to my inquiry :(

Accelleration enrichment.

All nice stuff in this post. We have a 3.3 liter turbo engine. Pinned case etc. Stock flat top Mahle pistons and stock cylinders. Although we run 72 lb per hour injectors., a k-36 turbo, sc cams (because we had them) a large custom intercooler and haltech fuel management. The heads and cylinders have Nirist rings. This motor turns HP from 480-680 depending on boost. For three years the engine has held together with no problems.

Go with at least 52 Lb injectors

Good luck with your project. Dyno Tune for sure

When we build an engine for race or street we ask the customer his/her HP wants. Then we go from there with injectors choosen for the wanted HP range. Injectors are rated and prefer to work at fuel pressures from 38-44 lbs. At that fuel pressure the spray pattern is optimized. A rising rate fuel pressure regulator will work if you need to run small injectors for good idle charactoristics but, I prefer to run the correctly sized injectors for the wanted horsepower.

I appreciate when tuners post their findings and recommendations. Thank you.

On a personal side, I like to see that you have a fairly big HP motor using SC cams (480 on the "low" side). Further proof you don't need big cams to make good HP on a turbo motor.

I have a 930/935 type car I run in Porsche Club racing. The engine in this one is a 3.8 single turbo. The crank has been modified and has 2" rod journals with NASCAR type bearings in order to turn higher RPMs (8600). I had cams ground special for this one, similar to 962 cams, for the higher RPM capability. The intake system is individual throttle bodies with two 55 lb per hour injectors per cylinder. also controlled with Haltech this engine produces 800+
I found that the higher RPM was really not needed to make the power but, it is nice when accelerating out of turns on the track..

Goran, going from memory (still need to read MS manual in more details), I think you can use rate of change of MAP for accel enrichment so can do without TPS?

Yeah, It could probably work depending on how big plenum you have but advantage of using TPS is that it's pre-emptive.

I don't know how big difference it makes though. Probably not much on inherently laggy turbocharged engine.

My concern with using TPS is that when going from cruise (no boost), it doesnt make sense to enrich just yet unless boost is up. I'm hoping the "standard" map will take care of rising fuel need in this case (as RPM will rise) until boost comes in.

I understand what you are saying, but I don't agree - at least not with the TEC3r. By using the TPS, I can set the software to add fuel via a variable time pulse width adjustment that adds just enough fuel (say, and extra .5ms over 1 second) that immediately reacts to TPS movement and gets the engine to respond quicker to WOT or really, any acceleration. With a CR of 8.0:1, this is a big difference when compared to a NA motor at 10.0:1 on the track. This feature will help spool the turbo just a bit faster.

I am a firm believer in using the TPS and MAP (not the "blend" feature) to tune a turbo motor. The quicker you can get an AFR to 11.5:1, the quicker the turbo will act in bringing up boost. A combination of TPS and MAP will give you immediate fuel (and spark advance, if you tuned it correctly) and is a noticable kick over not using the feature.

umm... one more thing to resolve then :(
Don, did you use the stock TPS or ???

Either will work. I use a ford part because I have an accufab TB.

So after 20 hours this weekend of swabbing out nooks and crannies with an alcohol soaked Q-tip, cleaning old gasket material off of critical surfaces, checking oil passages, punchlisting gaskets and seals and clean, clean, cleaning the ever loving snot out of everything with brake cleaner, link-free wipes and alcohol.... I've got a table full of parts bagged and tagged and ready for assembly. I'm meeting Chuck Miller at MillerSports tomorrow morning so he can oversee me beginning to put the beast together. I'm so tired... but excited. :p Pictures as entropy retreats.
Mike

Short Block
 

Some pics for your viewing pleasure. Points of interest include the shuffle pinned case and the steel intermediate shaft gear and matching gear on the crank. The steel intermediate shaft and crank gear are from a 964 engine. They measured out perfectly with the same gear ratio. Should be quieter and more durable. The rest seemed to go fairly normally. Progress! Now I'm starting to gather my thoughts about the Megasquirting of the beast (any working config files will be gratefully accepted :)

Mike

http://pickettweb.com/Porsche/SB/Ima...lock%20006.jpg


http://pickettweb.com/Porsche/SB/Ima...lock%20007.jpg


http://pickettweb.com/Porsche/SB/Ima...lock%20010.jpg


http://pickettweb.com/Porsche/SB/Ima...lock%20012.jpg

LOOKING GOOD! I should have my parts back from Performance Developments in a week or so...then I'll be right there with ya!