Turbocharger Upgrade -- Opinions & Experiences Needed

[Overpaid Slacker]

The 930 ("Die Rakete") is no longer scaring the bejesus out of me when I let it off the leash, so it "needs" upgrading. The next upgrade path goes squarely through turbochargerland and I'd like the advice/experiences/preferences of the Pelicanites as to the "best" aftermarket turbocharger.

The following information may be helpful:
This is a street car, with occasional forays into DE and AutoX in the near future.
1978 930
3.3 liter motor, rebuilt about 10k miles ago
ported/polished heads
964 cams
twin plug
Electromotive TEC-1 (running ignition but not fuel)
low ratio ring & pinion
european headers
Kokeln intercooler/shuttle-valve
stock wastegate (set at 12 lbs/ .8 bar)
boost currently starts around 3500 and comes on in earnest around 4000.

I'm currently leaning toward the Kokeln turbo, but I'm open to other suggestions (K27, Garrett, AirResearch, etc.)

The budget is about 1800, and I'll probably be adding an EBC at some point in the near future.

This car is new to me, so feel free to state the obvious; I won't take it personally.

Thanks in advance.

JP

[john walker's workshop]

8# is barely more than .5 bar. why so low? you should be able to run 1 bar without pinging, or at least .9. makes a LOT of difference. the K27 and a full width intercooler would improve it. what's the cam timing now? was the intake ported to match the heads, as well as the injector blocks?

[widebody911]

Somehow I don't think this quest will get very far on $1800, unless you left out a zero (or two!)

[lukeh]

I goy my k27 for $1,100 about 18 months ago. I still see them for that price. Ask the same question at www.911turbo.com for more and better answers. You won't get much turbo advice here and at the other sight Steve from Imagine gives out great ideas and advice.

[Overpaid Slacker]

john --

First -- mea culpa -- .8 (point 8) bar is what I should've typed. I'll go back and fix that after I've posted this.
The p.o. (whom I trust) tells me that the cam timing was set just at the perf. end of the Porsche spec., but within such spec. He doesn't remember the exact degree figure. The port/polish was not an extensive job (no flowbench e.g.) but as new injector blocks used during the rebuild, those (and other) "edges" were smoothed.
As for full-width, if that means I lose the a/c, then I'll probably stick with the Kokeln intercooler.

Thom --

$1800 doesn't sound reasonable for a turbocharger? Have I missed something? It's already a 3.3L turbo, I'm just looking for an appropriate turbocharger to replace the stock turbo. If this upgrade breaks $2000, fine, but I'm seeing Kokeln for $1400 and K27s for less than that. By all means, let me know if I'm off the reservation here.

Best,

JP

[5axis]

KKK Turbo

search has some use on occasion

89 turbo cab

[Overpaid Slacker]

5axis --

First of all, I get hip-mo-tized by your Avatar.
Second, I tried the search and found only a discussion from about two years ago from a couple of "guests."
Pelican Forum Link

What the post that I've linked to lacks that would be helpful to me is any discussion of the relative merits/flaws of the top turbochargers out there, esp. given the current config. of the car. As per Chrisitian's insight (which I thank you for), it may be academic at the levels of performance I'm after, but that advice itself is the kind of insight that will help when it comes time to bust out the MasterCard.

Thanks.

JP

[widebody911]

My comment was more along the lines that the upgrade usually doesn't end with a single piece of H/W.

Originally posted by Overpaid Slacker

Thom --

$1800 doesn't sound reasonable for a turbocharger? Have I missed something? It's already a 3.3L turbo, I'm just looking for an appropriate turbocharger to replace the stock turbo. If this upgrade breaks $2000, fine, but I'm seeing Kokeln for $1400 and K27s for less than that. By all means, let me know if I'm off the reservation here.

Best,

JP

[Don Cothard]

Went with the garrett last year (stage 11) 1700.00 and was sold as bolt on their idea of bolt on and mine is differant. Install took two weeks at a porsche dealer (another 1700.00). All that said I couldn't be happier with the early spool up and boost of the unit.If you can diy so much the better.
Don

[5axis]

Cool huh?* I like to think of it as a never ending Bay Watch episode

As mentioned by Luke, these guys are helpful and reasonable.
*http://www.imagineauto.com/ With your budget you are very close to the EBC and a K27. Or you could chase Bruce M off into the HP stratosphere and $$$ to match .*
Only in my dreams for now.

[TRE Cup]

We like the Kokeln unit- it is supplied with a new inlet pressure line, bolts right on, and gives us a better response curve than the K 27. Our clients like the increase in power over a K 27 as well.

[beepbeep]

Cheepest and easiest:

Replace stock 3DLZ (horrible turbocharger) with K27, raise boost to 1.0 bar (you have dual-plug ignition anyway, so pinging shouldn't be a issue) and you'll have at least 40 new ponnies...

Heck, you could probably do it yourself.

[finadict]

We also have a 3.3 turbo, but it is full boost well below 3k closer to 2600. Its not modified nearly as much as yours, but I did it it in stages so I can share our experience. Stock was pretty as you discribe yours maybe a few hundred more RPMs for full boost. Adding B&B exhaust and a K27 that helped, full boost was around 3200. Koklen IC with the newer pop-off and SC cams lowered initial boost to about 1800 and full boost at about 2600. With ours no one thing made alot of difference but the combination did. it sounds like your missing one piece of the puzzle. I think the stock turbo can be improved on, K27 unless you drive around redlined, I also have heard good things about Koklen Turbo.

[WydRyd]

How much HP do you want to make from the upgrade and in the future?

If you are looking at remaining "below", say, 450HP, then a K27-7200 will certainly suit your needs

However, if you intend to keep modifying that bad boy, I suggest going for a Garrett unit that can flow the sorts of HP you are looking at. T04E for up to 500-550HP, T60-1 for mid-high 500's, T60-2 for up to 600HP etc...

The best 'bolt-in' replacement is the K27-7200.

[Overpaid Slacker]

WydRyd --

I figure I've got about 400 hp right now (with pretty conservative ignition profile running on the Electromotive and .8 bar set on the wastegate). The PPI mechanic recommended leaving the ignition and boost where they're at for engine longevity's sake. I can't say I disagree with him, although sooner or later I know I'll succumb to temptation . . .

I'm probably looking at/for around 475-500 hp, but I'm not obsessed w/ any hp figure in particular. I'm more interested in enhancing low-end pull/lowering the boost point.

TRE Cup --

How would you characterize the difference between the Kokeln and the K27 response curves?

I realize that any of the options people have mentioned here will be "better" in any number of ways than the stock (read: "truck") turbocharger I've currently got. However, as WydRyd and others point out, different turbos have different characteristics and strengths, and I'm looking to assess them against each other. I haven't yet found on the web any empirical comparisons.

Best,

JP

[WydRyd]

From my research, the Garrett T04E sounds like an awesome Turbo, capable of spooling up just as quick (if not quicker) than a K27-7200. The compressor is much more efficient than the 'old' K27 and T04B's AND it is capable of flowing well into the 500's.

If I had the choice to do it all again, I would have gone for a Garrett T04E unit as I'm only now realising that I'm not too far off the K27's limits.

If I were you, that's the path I'd take, but each to his/her own.

I can't say much about the Koklen units. Never known anyone who's using/used them.

Typically, the ball bearing units get great reviews/comments, so a T04E, or T60-1 is the way to go.

Bruce.M has a T60-1 I believe, so maybe he'll tune in here.