nize

i thought i'd write a review on my recent custom turbo upgrade.

the turbo upgrade i was looking for had to meet these very difficult qualifications;
1) fastest spool possible, must spool like the stock turbo-s turbocharger. i was not willing to sacrifice lag for power. i was looking for 18psi by 3krpm with no dropoff to redline.
2) be able to support 350whp.
3) be plug-and-play. i wasn't willing to jump through hoops and hunt down special nuts and bolts and clamps and adapters for a turbo swap.
4) the vendor must be willing to communicate with me about exactly what i was paying for. sadly, this dropped vitesse off the list as i wasn't able to get any detailed specs regarding their turbo for a meaningful comparison. i would love to see a back-to-back vitesse turbo review with dyno graphs.

after much research, debate, and discussions, i decided what i was looking for was a garrett dual ball bearing center cartridge with a 50-trim compressor and #10 hot side. fortunately for 951 owners, there are many porsche specialists to choose from when considering a turbo upgrade, and many more choices of turbochargers. unfortunately and understandably, most vendors will not tell you the exact specifications of their turbos for fear of copy-cat vendors stealing their designs. following is a list of the vendors i considered during my turbo hunt, and the reasons why i did not choose to go with them. they are not in any particular order.

vitesse stage2;
this was actually my original first choice. although i have heard great testimony regarding their turbochargers, i could get no technical information regarding what exactly i would be buying. this combined with no concrete before and after dyno graphs plus the extremely high price (they were by far the most expensive) made me choose to seek a different vendor. i believe if i'm paying premium for something, i should know exactly what i'm paying premium for.
http://www.vitesseracing.com/html/turbo.html

ultimate motorwerks;
this is a vendor local to me and i have heard great things about their 'zero clearance' turbos, but i have also heard that they need to be rebuilt often because they coat the inside of the compressor housing with some material to get the 'zero clearance'. i wanted more reliability and less maintenance so i looked elsewhere. there is also no technical information regarding these turbos.
http://www.ultimatemotorwerks.com/

innovate motorsports; (no longer in business)
i sent an email but got no response. their website also does not contain any information regarding their turbo product(s).
http://imsmotorsports.com/

edit 12/06/2007: it seems the ims website has been hacked, and/or the company is no longer around. if anyone has info, please let me know.

034 motorsport;
this is actually the least expensive vendor as far as listed price is concerned. the only concern i had was that they were unable to provide 951-specific support or advice so i had a feeling i would be on my own as far as special adapters, oil lines, and fittings were concerned. for the true do-it-yourselfer, this may be the most cost-effective route.
http://www.034motorsport.com/product...8f26063501ba33

john milledge engineering;
this is another vendor with a legendary reputation in the 951 world so i naturally sent him an email with my initial request. he replied to the first email stating that the group-a type turbo was no longer available and that my target goals were unattainable, then failed to reply to repeated emails asking for more information. i got the impression he was a difficult person to deal with and unwilling to work with customers. or maybe i just got him during a bad week.
http://www.jmengines.com/index.htm

edit 10/24/2007: it seems john millege shut down. it's always sad to see a longtime 951 specialist close shop. it could also explain why he wasn't enthusiastic about selling me a turbo. good luck john!

edit 5/24/2008: it seems john milledge hasn't shut down after all, and is now selling ball bearing turbos. no prices nor specs listed though;
http://www.jmengines.com/tables.htm

lindsey racing;
what i love about lindsey racing is that they give you all of the information you might ever want regarding their products. what i don't love is that all of their turbos are oldskool journal+thrust bearings with crazy lag and that no ball bearing turbos are available. who cares if you're making 400hp if you have to wait until 5000rpm for full boost? dave should get with the times and stock some dual ball bearing turbos.
http://www.lindseyracing.com/mm5/mer...944TURBOSSUPER

edit 10/24/2007: it seems lindsey is now (finally) offerring true garrett dbb turbochargers. it's about time, dave! lindsey does not have the stock turbo water-pipe mod available. this means it would be up to the customer to come up with their own coolant plumbing, which is a difficult task that requires custom welding. this is stated on their web site: Customer will be requried to adapt their water and oil connections.

speed force racing;
this is another vendor with a great reputation. unfortunately, i do not have any firsthand experiences with sfr. they may be another great source for garrett dual ball bearing turbochargers for the 951.
http://www.speedforceracing.com/prod...bochargers.php

pauer tuning;
vic at pauer tuning was not only very prompt to my initial emails, he was also forthcoming with information regarding turbochargers in general and why i should choose his product (or not). he was also willing to beat any competitor pricing and provide after-sale support and installation advice. throughout the entire initial exchange, i kept thinking 'now here's a vendor who really knows how to treat potential customers and is as excited about 951's as i am' so i chose to go with him.
http://www.pauertuning.com/turbos.htm

i should also mention that i have three local 951 friends who are also in the market for a turbo upgrade and they were all eagerly awaiting my research and legwork so they could copy my results and purchase. i didn't mention this to any of the vendors up front because i wanted to see how my single purchase went. by the time i placed my order, one other local 951 buddy also ordered the identical turbo from pauer tuning so vic got a double sale. two other local 951 guys will be ordering their turbos from pauer tuning as soon as they see my dyno results.

note to vendors: treat your potential customers right, because they have friends !

this is a photo of the new turbo next to the old turbo;


and a side-by-side shot;


this is a video of the fully assembled turbo being blown by mouth on the hot side. it spins very easily;
http://www.youtube.com/watch?v=Ry5dTFg3RSM

components needed for a hassle-free plug-and-play turbo swap from pauer tuning, all are available from pauer tuning;
-the turbo itself
-modified oil line and related components (different sized holes/threads for the oil feed)
-modified water pipe and related components (different sized holes/threads for the water, and the stock water pipes will not clear the larger aftermarket compressor housing)
-aluminum plate for mounting gasket (aftermarket turbo does not fit perfectly over stock rubber o-ring seal)

additional component needed, this is NOT available from pauer tuning;
-if you are using the stock intake system like i am, you will need some type of mod to get the stock j-boot to fit the bigger 3" compressor inlet. i used a piece of pvc plumbing pipe with a 30-degree bend and a rubber no-hub coupler, which cost around $5 total at home depot. i would recommend the lindsey j-boot adapter, which is what i have ordered and will be switching to for a cleaner install;
http://tinyurl.com/2975ne
edit: check the bottom of this post for the j-boot adapter mod!

potential problems that may prevent true plug-and-play;
1) the plastic cover on the back of the alternator needs to be modified, as the location where the electrical wire enters the cover will prevent the larger inlet of the cold housing from clearing whatever intake adapter you connect to the turbo (see photo). this is a very easy mod and it would seem that any larger diameter (ie; bigger) turbo inlet would require this to be altered.





2) depending on the orientation of the cold side housing, the installer will possibly need to grind the top of the turbo compressor housing down about 1/8 inch to accommodate the bottom of the intake manifold (see photo). i had to do this to make mine fit. it was relatively easy to do this using a dremel with a grinding stone attached. you'll have to be careful not to get aluminum dust into critical areas on your motor, and wear a mask to prevent breathing aluminum dust.



3) depending on the orientation of the cold side housing, the installer will possibly need to grind down one of the bolts at the bottom of the turbo holding the cold housing to the center section (see photo), because this bolt may not clear the bottom of the turbo mount and prevent proper mounting. i was lucky and did not have to do this, but i have heard that some people just remove this one bolt and keep it removed to simplify installation.



some gripes;
1) it seems the metal clamps holding the hot side housing to the center section is plated with chrome or some other material, and this plating will flake off and peel after the turbo heat-cycles a few times. this isn't a big deal, but does make it appear as if the part is cheaply manufactured. i would recommend using non-plated clamps, or using a sander to remove the plating before installing if you don't want chrome flakes later. this isn't a huge deal but worth mentioning.
2) the center section exterior will rust when exposed to water. again, not a problem but worth mentioning.

some praise;
1) as far as i can tell, this is a substantially larger turbo than the stock k26/8 that comes with the turbo-s model, but still manages to spool exactly the same as the stock turbo. using a standalone wolf3d ems with custom boost control, i was able to achieve 1bar (14.5psi) of boost with this turbo by 2800rpm, which is identical to the stock k26/8 turbo. the difference is that this turbo will easily hold that boost to redline. even when i tried turning the boost up to 18psi, and then 21psi, this turbo will not run out of breath like the stock turbo does. i do not have the mods in place to support higher boost, so i haven't tried anything higher than 21psi, though i'm certain that it will easily hold at least 25psi to redline, as i've seen boost creep and had to turn my boost settings down.
2) transitional boost, which is the boost recovery phase between shifts, is something that is rarely discussed in turbo reviews but i feel is important. the transitional boost with this turbo is much faster than the stock turbo. this is something that you'll immediately feel and notice.
3) vic at pauer tuning is a nice guy and is eager to go out of his way to help you. customer service and after-sale support is so far the best i have ever had with any vendor at any price.

overall, i am happy with this turbo upgrade so far.

edit addendum: here is a side-by-side comparison between the new turbo and the stock turbo;
these side-by-side turbo vs. turbo comparisons were performed on the same car with the same mods and the same tune. the only thing that changed was the turbocharger alone.

(note that 1bar=14.5psi)

stock turbo-s k26/8: 15.2psi at 2797rpm


50trim dual ball bearing turbo: 15.7psi at 2938rpm


stock turbo-s k26/8: 18.6psi at 2938rpm


50trim dual ball bearing turbo: 18.1psi at 3063rpm


edit: addendum 12/22/2007
i have been able to get 17psi by 2969rpm with the new dbb turbo. keep in mind this is the #10 hotside. an equivalent traditional journal bearing kkk would never be able to acheive this;


edit: addendum
i've figured out a better way to demonstrate the difference in spoolup speed between the stock and the dbb turbo, i've timed between when the turbo first begins to build boost, to when it reaches maximum boost. this demonstrates the differences in the amount of 'kick in the butt' aspects between the two;

stock k26/8 takes 14.4 seconds from 0psi to 20psi;


50trim dual ball bearing takes 8.3 seconds from 0psi to 20psi;


edit 6/7/07:
update on the j-boot mod from lindsey. here's my before hack job where i used a 2" to 3" plumbing no-hub coupler connected to a 30-degree pvc elbow pipe that i sawed off;


here's the lindsey j-boot adapter using a metal pipe;


i've heard some people had trouble getting it to fit properly, so i made a how-to. the easiest way to get a straight cut is to first trace the cut line, and then make the actual cut. i used a box cutting razor blade;




after it's cut off, you'll need to shave the four ribs off;


for some reason, lindsey's angle at the pipe weld is too big, so it doesn't quite line up correctly. what you will have to do when installing the metal pipe is to try to minimize the angle where the j-boot bends as much as possible, this is the key to making it fit right;


edit update 7/11/07;
i have heard from people trying to order the lindsey j-boot adapter that lindsey is now requiring you to buy one of their turbos if you want just the j-boot adapter. i guess that's one way of trying to force people to buy your turbos. pm me if you need the j-boot adapter.

edit update 10/15/07;
i was unhappy with the way the lindsey j-boot adapter pipe obstructed airflow through the bend in the j-boot, so after some more tinkering, i cut a section out to improve the fit. i'll let the photos do the talking;



before;


and after;


here is the long overdue dyno graph. the glitch at 4800rpm is due to their spark sensor messing up (it's been finicky with my car for some reason, which is why it's taken so long to get a good graph).

edit: 1/2/08;
i found out over the weekend that cylinder3 is down 25% compression, possibly due to bad/worn piston rings. it's obvious if this cylinder were working properly, the car would have made more power.

i'll let the graph speak for itself;



what is interesting to note, is that i've compared performance with the stock air box and snorkle versus just a filter attached to the compressor inlet.

the difference is significant, and it's definitely worth removing the stock air box and snorkle if you want maximum turbo performance.

all things being equal, the spoolup is about 200rpm faster without the stock afm/snorkle, but the real difference is after 4500rpm when the air restriction becomes really noticeable. the result is way more area under the curve and a gain of over 36whp.

it's obvious that most of the power and performance gains from a MAF setup is actually coming from removing the stock intake restrictions. if your mods can support it (MAP or MAF), i would highly recommend removing the stock AFM and snorkle for best performance gains.



edit: 01/02/08 (happy new year!)
i have heard from a local 951 track junkie that a stock honda intake snorkle is a perfect fit for a 3" turbo inlet on the 951. so over the holidays, i went to the local junk yard and managed to find a rubber intake pipe from an old honda prelude for a whopping $2. it does fit almost as if it was custom-made for the 951. does this make my car JDM ? yeah, i know, someone get me a k&n cone filter so i can get rid of this retarded sponge filter, please.



you can read my entire story that led to this turbo upgrade here;
https://rennlist.com/forums/showthre...8&page=1&pp=40

i will update this post with new information as they become available.

KuHL 951

Good write-up and very helpful. I'll be referring to it for sure very soon

Geneqco

Great post... looking forward to the dyno results!

Trucho-951

Glad to hear success stories, great post, very informative.

nize

thanks guys. post updated with vendor information and shopping experiences.

toddk911

Nice!

Looks like the cold side is obviously much bigger than stock but hot side is the same? I take it that is the main reason you see the same spool up as 26/8 ??

nize

it's a custom combination not available elsewhere. the hot side is actually closer to a #10, which is how it also gets the big hp numbers and holds boost past redline. if you talk to vic, he can hook you up with my identical setup.

Matt Sheppard

terrific post, nize

no "smoke and mirrors" here!

jyoon

my turbo s doesn't hit 15 psi with the stock 26-8 until after 3k. maybe something is wrong with my turbo, but i'd be suprised if you're new turbo is going to hit 18psi by 3k and hold to redline. sounds great if it does.

nize

are you using the stock wastegate? if so, that is why you can't get quicker boost with the stock k26/8. nothing is wrong with your turbo.

i'm using a tial 46mm dualport setup with independent standalone boost control from the wolf3d ems. it has datalogging so i already know i'm getting 18psi by 3k and holding to redline.

mwc951

Nice write up!

Who's software are you using?

nize

wolf3d ems, a plug-and-play system that's custom for the 951 available from lindsey;
http://tinyurl.com/3xfptk

or from randomems;
http://www.randomems.com/

toddk911

1 bar by 2,800 using #10??? WOW!!!

and still holding 18 to redline.

Awesome!

pete95zhn

Excellent write-up, way to go!

About those hot-sides, a knowledgeable turbo builder can play with different hotside and turbine wheel sizes to achieve results needed. There's quite lot of "room" to machine in #6 or #8 hotsides, so much larger wheels can be installed. This way even #6 turbine can sustain reasonable power ( but only at certain boost level, after that it becomes too restrictive ) while being low-spooling. Like my previous turbo.
Then there's the wheel question... I guess that we all know that 3K turbos are of old technology, but what I've heard from knowledgeable builders is that Garrett wheel technology is also from the '70's. They claim that certain Holset wheels are far better and thus spool faster with thrust bearings than Garretts with ball ones.

And now I'm going to wear my flame-proof suit... =)

nize

you wouldn't believe how much speculation, theorization, and butt-dyno testing i've run into during my turbo hunt. i have heard about the 'new and improved' wheel designs that supposedly spool quicker. i've also heard about zero-clearance (it works, but is temporary), clipping the turbine (basically taking a larger wheel and grinding down parts of it), pixie dust, and voodoo magic. not surprisingly, none of these magical turbos can provide before and after side-by-side comparison dynos with any other turbos, nor any sort of meaningful technical specifications for a scientific debate.

as far as i could tell, the garrett dual ball bearing design is the only one that has been proven to actually spool faster with a bigger wheel and has the data to back that claim.

so why doesn't every vendor sell dual ball bearing turbos? the reason is slim profit margins. in the search for more power, turbos are a big profit business. the cheaper you can get one and re-sell for higher markup, the more profit you can make. because the garrett duall ball bearing is the hottest turbo on the market, you can't get a dual ball bearing for cheap, so vendors can't make the same kind of profit as they can for a traditional cheap thrust bearing. while a thrust bearing turbo in my configuration would retail around $700, a dual ball bearing would cost over $1500. imagine if you could sell a $700 turbo for $2000, you'd make some nice profits. that's why vendors talk up thrust bearings.

next time you hear someone talking up thrust bearings being just as fast or even faster, ask them if they sell dual ball bearings as well. chances are, they don't. then ask them if they have before/after dynos. again, chances are they won't.