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Architecture & Porsche's
Join Date: Jan 2006
Location: Austin, Texas
Posts: 3,189
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Turbo928 update: after 5 months of play time...weeee
I've been getting a few emails here/there on how the car's doing.
I have not been under my car (hood or chassis) since I installed the turbo kit May 11 (the day before dyno day). I mostly drive the car to events on the weekends, as there's always something going on in Austin. I average 17mpg city when shifting conservatively. The car's temperature runs at about the 1/3 tick, same as stock (I see a longer time to heat up to the 1/3 tick mark now). I passed emissions with flying colors a few weeks back, both idle and the 2000rpm cruise...with no cats & 30# injectors. I'm running the Stage 1 928turbosports kit with the following options: T67 DBB (dual ballbearing) turbocharger, which is water cooled & added to the installation complexity, but worth it. Also, I have the Intimidator exhaust that people hate in photos but love in person: and it sounds incredible! Other than the boost controller conservatively set at 5.5psi, no other changes have been done. I'll install an intercooler over the fall/winter, just ran out of time this summer...it was hot as hell too. Mark  ...now with Black-centered Fikse's  I'll be at ThirdCoast in Mid November for the Sunday show...will be happy to show/give drives, let people drive her....I should have 20,500 miles on her by then!
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Porsche Club Racing National Scrutineer '89 Andial 951 '82 928R '74 911 RSR 3.6 |
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10-28-2008, 09:23 AM
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Network Native
Join Date: Jan 2007
Location: SoCal
Posts: 10,349
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Do you have any numbers for that emissions test or just pass fail?
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10-28-2008, 09:25 AM
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Architecture & Porsche's
Join Date: Jan 2006
Location: Austin, Texas
Posts: 3,189
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i think for idle it was like 68/220, and for 2k cruise it was about 120/220, but I have the paperwork in my car (on the lift). I'll get that for you, haven't forgotten.
Mark
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Porsche Club Racing National Scrutineer '89 Andial 951 '82 928R '74 911 RSR 3.6 |
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10-28-2008, 09:28 AM
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Registered
Join Date: Oct 2008
Location: Columbus, MS
Posts: 845
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Hi Mark,
I'm new to this forum and am very curious about the turbo idea. Where can I find more info out about the kits cost, install requirements, etc.... Anyone have one on a S4? Is it as costly as aSC...about the same...or cheaper? Thanks...new member and learning alot. |
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10-28-2008, 11:17 AM
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Architecture & Porsche's
Join Date: Jan 2006
Location: Austin, Texas
Posts: 3,189
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Hi Dean,
There are a LOT of Supercharger pushers around for 928's. I used to be one of them, however like many, I wanted to turbocharge the 928 just to be unique. This is much more difficult to do & only a few have done it. I did it & kitted it, however the market appears so saturated with SC cars that there's just not that much interest in turbocharging the 928. SC's make power, but the delivery is just plain boring to me (My opinion, I'm entitled to state my experiences) by comparison...much like driving a Viper vs a similarly powered 911 turbo. Go to www.928turbosports.com. This is my site, my kits. I developed them in harmony with boostlogic: World-record holding turbocharger kit builders for the supras (Fastest standing mile, 1/4 mile 6-speed car, 1/4 mile auto with IRS, etc). I have a few kits left, but once sold, I'm out of the market. I don't make enough $ to make it worth my while. They are a hoot to drive: very exotic as you have all the low end torque, but about the time that things would start to get boring when accelerating on a 928, you're holding on for dear life as you fish-tail up to about 80mph. They're actually cheaper as they include a full exhaust system. A Base kit is $5300 & includes the wide-band O2 sensor for tuning. Mark.
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Porsche Club Racing National Scrutineer '89 Andial 951 '82 928R '74 911 RSR 3.6 |
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10-28-2008, 11:32 AM
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Posts: 135
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Mark - I'm going to ask you a few questions, and if you don't feel like answering, let me know straight:
What is the proper rear mount turbo sizing for a 4.5L and 5.0L 928 engine? Is it true that with Rear/mid mount systems, the Turbine housing and impeller must be made much smaller to get the most out of the slightly slower and much cooler exhaust stream? Is it true that opposed to the exhaust side, the compressor side much be very large to deal with the increased volume of tubing going to the engine from the rear? Baring the debate over water cooled and separate or same oiling systems for the turbo/engine, the turbo requirements seem to be Single - .60-.80 turbine, and .80 or above compressor Dual .45 turbine and .60 compressor? |
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10-28-2008, 01:24 PM
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Architecture & Porsche's
Join Date: Jan 2006
Location: Austin, Texas
Posts: 3,189
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I'm using Precision turbochargers: great warranties, proven, so my nomenclature many not meet Garrett's for example. 4.5l: I was gonna use a T50 or T61 BB turbo, with a p-trim turbine (large) & a .68 or .81 turbine housing. I'd try both turbo's & think the T61 would provide cooler air.
Mid-mount systems: Heat is just one factor, the other is volume. 5.0's making 330hp make a LOT of exhaust volume, esp. in a single 3" system. I use the largest tubine on this mid-sized turbine to ensure there's no excessive back-pressure. My car still breathes freely enough to spin the tires off-idle ala a stock 928, but is boosting before 3k rpm. Compressore size: the T61 turbine housing is as large as a K27: pretty small. The more area of tubing you have, the more lag you generate, but we're talking 100-200rpms between 2.25" tubing and 2" tubing. NO worries there. Watch my video's on youtube & streetfire: it boosts fast, intercooler or not. Large power supra's have massive IC"s: 5" thick, 30" long, 14" high, and their turbo's have to boost that area as well: it just takes a wee bit more rpm/time to do so, nearly irrelevant on a 5.0 engine using a low-boost turbo set-up for 500-600hp. I think a 4.5l might benefit from a 50-trim turbo as it will spool a lot faster & hence, more fun. I've seen trucks make 390rwhp on a 50-trim turbo at 12psi on a Toyota tacoma: plenty of juice...considering my healthy 4.5l car dyno'd about 190rwhp. A dual 60-trim turbo equipped car could have the capacity to make over 1000rwhp: I'd imagine there'd be some lag there...maybe spooling about 4500?? mark
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Porsche Club Racing National Scrutineer '89 Andial 951 '82 928R '74 911 RSR 3.6 |
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10-28-2008, 01:43 PM
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Architecture & Porsche's
Join Date: Jan 2006
Location: Austin, Texas
Posts: 3,189
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BTW, I'm well aware that some are waiting for more dyno's & such: I'll be back on within a week or two.
Other updates: L-Jet, CIS, & Auto S4 turbo kits: L-jet & CIS kits were never tested as test-cars came/went (local 928er's). I have an S4 auto kit being installed out of the country, so that in itself is time consuming, but I'll update as I hear things -
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Porsche Club Racing National Scrutineer '89 Andial 951 '82 928R '74 911 RSR 3.6 |
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10-28-2008, 02:00 PM
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Architecture & Porsche's
Join Date: Jan 2006
Location: Austin, Texas
Posts: 3,189
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BTW, I'm well aware that some are waiting for more dyno's & such: I'll be back on within a week or two.
Other updates: L-Jet, CIS, & Auto S4 turbo kits: L-jet & CIS kits were never tested as test-cars came/went (local 928er's). I have an S4 auto kit being installed out of the country, so that in itself is time consuming, but I'll update as I hear things -
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Porsche Club Racing National Scrutineer '89 Andial 951 '82 928R '74 911 RSR 3.6 |
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10-28-2008, 02:00 PM
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Turbine housing - smaller housing, more resistance to air flow?
Ptrim turbine - that would already be matched to the turbine? |
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10-28-2008, 02:06 PM
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mark - check out this ebay ad - 120314779395
Seems like what you describe is not readily available? |
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10-28-2008, 02:08 PM
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the reason that, on the internet at least, people talk about this "master power" turbo, since the sizing seems to fit the program (smaller exhaust housing, bigger compressor:
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10-28-2008, 02:11 PM
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10-28-2008, 02:26 PM
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Architecture & Porsche's
Join Date: Jan 2006
Location: Austin, Texas
Posts: 3,189
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Anything T3 is for basically, 4cyl engines. T3 is the smallest turbine-section turbochargers available. Mid-size turbochargers are appropriate for street use on most all 6-8cyl cars.
The P-trim is the largest (highest flowing) trim available for the mid-sized turbochargers from Precision: it's a 3" wheel & requires a 3" exhaust minimum. The turbine housing correlates to the power & size of the engine. 500hp-600hp supras usually run a p-trim with a .58 housing. 6-800hp supras usually run a .68 housing. 800+ usually run a .81. I have a .81 & recommend it as the 928's engine is a 5.0, not a 3.0, and for off-boost flow, the .81 flows more & allows for less back-pressure, both on-off boost. This is also the recommendation from Precision for our cars as well as Boostlogic's tuner, Justin. I did some detonation testing back in '05, & found a wee bit in the .68 for the 928's running a few other detonation-inducing variables, but none in the .81. I can also feel the engine breathe & rev easier with the.81, much like a stock-exhausted 928. Mark
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Porsche Club Racing National Scrutineer '89 Andial 951 '82 928R '74 911 RSR 3.6 |
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10-28-2008, 02:30 PM
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Do you think the half liter reduction to 4.5L would make a difference with your .81 recommendation?
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10-28-2008, 02:35 PM
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10-28-2008, 02:36 PM
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Architecture & Porsche's
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Location: Austin, Texas
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for a 4.5l , I'd probably try a .68 first. If I thought it were lazy, I might try a .58.
Keep in mind a 4.5l 928 makes about 2/3 the hp as a 5.0 32v car. That turbo states a 2.5" outlet: that's very small: enough for a 4cyl, but prob. too small for a boost 6, let alone an 8cyl.. I can correlate with Precision's turbos, but am not savvy with other makers/nomenclature. I am by no means a turbo expert, I just know what works well on a 5.0 928.
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Porsche Club Racing National Scrutineer '89 Andial 951 '82 928R '74 911 RSR 3.6 |
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10-28-2008, 02:42 PM
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Did you see the master power turbo
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10-28-2008, 02:54 PM
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This 3.5L V6 gets a T04E:
http://www.zimbio.com/All+World+Automotive/articles/2145/FS+STS+rear+mount+turbo+kit+G35+Sedan |
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10-28-2008, 02:59 PM
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Join Date: Aug 2006
Location: Cincinnati, Ohio
Posts: 1,019
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Brendan,
You have to first pick the compressor for the engine size and then focus on the turbine. Yes...the turbine and housing for a rear mount are typically smaller than front...this aids in getting them to spool since the air has lost some temp (i.e. energy) from the heads to the back of the car. Remember, it is the heat and pressure differential driving the wheels...not just pressure as some people believe. You can measure temp drop across a turbo...that heat went into powering the compressor. Rule of thumb...a turbo sized for front mount if mounted at the rear would be very lazy to come on boost. The air loses some temp and pulse energy at the rear, so to compensate you size the turbine and a/r down. Lots more to turbine sizing than a/r though....many turbines, housings and a/r ratios in those housings. Not an exact science either. JK
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Kuhn Performance Technologies, LLC Big Gun: 1988 928S4 Twin Turbo, 5-SPD/LSD 572 RWHP, 579 RW ft-lbs, 12 psig manifold pressure. Stock Internals, 93 octane. Little Gun: 1981 928 Competition Package Twin Turbo, 375 RWHP, 415 RW ft-lbs, 10psig manifold pressure. Nikasil Block, JE2618 Pistons, 93 octane. |
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10-28-2008, 03:20 PM
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