Steve Weiner-Rennsport Systems

Gentlemen:

Rods and hardware will not be an issue here, installing Pauter or Carrillo rods will take care of that and doing the case oiling mods, crossdrilling the crank, and even using the 962 oil pump will assure a solid, durable lower end. Fact is, turbo motors are FAR easier on these components than their N/A high-compression counterparts.

The real limitations of these engines are mechanical in nature. In simple terms; high cylinder pressure issues related to keeping the heads on the cylinders and maintaining the seal between the heads and cylinders.

This situation has not really changed since the 935 days and with the use of 100mm or 102mm cylinders, its VERY tough to keep the heads from bending (even with welding) and the studs from stretching.
The 935 had studs far better than any production stud past or current, and those engines were smaller bore motors designed for 1.4-1.6 bar use.

We've done a number of 3.6 litre twin turbo motors in the 650-750 HP range that make this power at 1.1 to 1.2 bar. We race them at 1.0 bar for longevity as the heads lift & bend at 1.2.

As long as you have good fuel (VP-116) and twin-ignition, these big bore motors will not detonate very easily. Careful attention to setting deck height for maximum squish really pays dividends, too.

Just my opinion, but rather than trying to stuff air into the engine at high pressures, I'd suggest concentrating on airflow enhancements and efficiencies at reasonable boost levels to keep the engine from being a 24-hr wonder.

BTDT, SOOOO many times over the past 25+ years.

PorschePhD

No problem TB....I appreciate the respect thing. We have pretty good data on the 930s if you would like to see the info. The results were pretty staggering. I think with the OBDII cars it becomes and issue of allowing the computer to know what is going on. The 996TT has proven to us that the physical effect isn't good enough and the issue becomes computer involvement as well. Placement as we have found out is everything.

As far as the Lancer, then the new Subaru is coming out with it. I knew one was external and the other was going to be internal. Crazy stuff

Joe@Fabspeed

Kevin
do you have more pictures of the stock 993TT turbos versus the K24/GT1s and the garret ball bearing pieces. Can you install Garrets in the stock K16s and have reliability.
Thanks
Joe
993TT engine and trans 18K in the house- powdercoated and detailed- looking actively for 993 Cabriolet 6speed 2 wheel drive (Silver/Arena Red/Green) to inject 500HP

Kevin

Yes, I have pictures.....
No, THEY ARE NOT RELIABLE, and non-repairable!!!!!!! bad, bad, bad...
Jump over to the 996TT forum and see Sharksters 1.5 bar instant boost with our K16's.........

viperbob

Kevin,

I have a set of k24 Porsche Motorsports Evo turbos (996 part number but made for 993TT). I have no idea on the turbine / compressor wheel configuration. Do you know anything about them, and what can you do to better this? Zero clearance, titanium wheels, larger compressor wheel, whatever.

Please let me know. I know there are a couple of more ponies here, and I want them...

Kevin

Bob;

Without seeing pictures of the turbine housings and compressor housings it will be tough to guess. I'd assume K24's... Can your engine handle 1.5bar? A little hint, buy a set of used K16's and tell be how much air you want. On the turbo dyno stand the only way that one could get the titanium wheel to burst was to drill holes into it and spin it past 200K..... Now with the zero clearance...... Intercooler inlet temp will be dropping for all of us!

Garrick Louie

LOL,

Bob...the other day we talked I thought you said you had enough power, I knew you were bluffing

viperbob

That was yesterday Garrick. I've gotten use to it now and I want more. Typical addiction response, and I'm OK with it..

poorb0yw

Kevin-
What are the reliability issues you have been having with the Garret systems? How long do these usually last?

I was planning on using two GT28R (full ball bearing T28 with slightly larger compressor housing) for my little project.
The price I can get them for is definitely cheap.

TB993tt

Kevin
I am reluctant to do more "bolt ons", I spent years and $ doing them until I made the decision to pay for a dyno proven "package" BUT I am informed my turbos (just been reconditioned) are stock K24 sports -whatever that means ?
I have a set of well used stock kkk16s 993tt turbos in my garage and would consider letting you work some magic on them.
I am a little concerned, what do you mean by "can your engine handle 1.5 bar" ? are you meaning that your turbos are so durable that they will do 1.5bar all day long or are you saying that they work best at these boost levels ? (FWIW my engine sees up to 1.6 bar at 4500rpm))
I can't tell you in CFM what air I need, but the same profile as K24 sports (with the ability to flow enough air for 600hp) but with even quicker spool up would be nice.
Can you list the specific changes you would make to a K24 Sport and the benefits they bring, also any disadvantages like durability. Lastly can you give us an idea on pricing.
Thanks

Kevin

TB

I understand your reluctance! The Billet wheel don't have spikes of 1.5-1.6, they have sustained pressure levels.... If your programming is at 1.0 your frequency valve will be very active. The cure is to custom dial in the wastegate/valve to work with the programming. With regards to your K24 sports, there could be about 4 or 5 similar possibilities. If you undo your air intake tube and measure the inducer I will be able to tell you what you have. I'd love to build you a set of K16's. I have said this before, apples to apples, the K16's will out perform the K24's ON our cars, until we go over 3.8 ltrs.

Princeton;

In higher HP applications for our cars, the ball-bearing units will not last... Period, and as you know they are not rebuildable.... Been there, done it, know it.... With that said. I can CNC that Garrett wheel into a K16/24... With our new zero clearance turbo's, other wheels become better choices.

Jeff 993TT

Sorry for the newbie question, but what are the different bearing choices for turbos?

I assume that the stock K16's use some sort of oil film bearing? Is that better/worse than ball bearings? What about ceramic bearings?

TB993tt

Kevin
Having re-read your post several times I think that you believe that my set up makes the turbos "spike" up to 1.6 bar - that is not the case, the Motronic 5.2 has been programmed on the bench dyno to allow the boost to build until it reaches certain limits sometimes in 6th gear up to 1.6bar (determined by what the sensors tell it but mainly temperature dependant) then it winds back the boost to peak power then it usually allows a bit more as it approaches the 7K limit. This is the way the top German outfits tuned these cars - what is your interpretation of the boost profile of a tuned 993tt ?
Thanks

viperbob

Kevin,

You live in the world of reality (with my old K16s too). I don't have to cross that plane (I have an MBA in marketing), plus I have no K16s. So I would like to see what kind of cool things you can do for my K24s. Street driving and a little bit of lag of (2500 vs 3000 etc) is of little consequence. I am setting my car up for the track and optimizing power bands on the car to never get below 4000 RPMs on the track (and yes boost vs no boost at this level yeah yeah....). So I'd like to try this, and if it doesn't work, OK but I still want to try. So what can we do to these to make them work on the car?

Thanks
Bob

Kevin

TB;

Believe it or not I do understand what you are saying, and hopefully you don't think that since I am across the pond, that I feel that we can always do things better. On the other hand we might be able to utilize a different approach to things. The bottom line is I have a interest in our cars and can steer resources to pet projects. This developement is one such project. The turbo's are not going to spike they are either going to be allowed to compress the air or dump it through the wastegate. Without seeing a torque curve and on the fly boost readings we can go back and forth and thats not my desire. Your programming is probably the best that is available. And, for the record I'd swap you ECU's any day of the week. My only point is that most KKK cast aluminum wheel spike at a high pressure levels, but cannot maintain it! I would ask you to view a car on a elevated dyno and watch the wastegate moving through the pull. Pretty scary event.... I'm going to go out on a limb and say that as we post to each other on this forum, my heart is to provide all of us that have these cars the best technology that is available at monies that are a fraction of the known tuners.

1)Using the latest Billet Aluminum @ Titanium compressor wheels for our 993's & 996's. The titanium wheels are 40 times stronger than cast wheels. That means that I can take a K16 and spin it into warp without having to worry about it bursting.

2)Personally going to the factory and talking with the engineers about pet projects and seeing the new developements for our cars.... Like zero clearance units, and variable vane technology! I must include a disclaimer, in uncertain terms did the engineers relay to me there secret compounds, however, they did steer me in the right direction. This coming week we will have are first set of zero clearance K16's. You folks will be the first to see it. This process can be applied to any turbo out there.
3)Billet backplates designed and made to adjust wheel height to maximise compression. All KKK turbo's should have them, why, remove you compressor housing and look at the wheel, it is sunk into the backplate a good .020.

Viperbob- you tell me what you want and you will get it! No smoking mirrors! Bob, personally I'd lend you a set of cores and build them up, with a future core charge, that on a later date you can buy from someone. If you don't like them (K16's) I'll convert the K24's at no charge to you! (I'd transfer all the major components from the K16's to the K24...)
However, if you want the work done to you K24's I'll do it!
Jeff;
The bearings in the K16 are the same as the K24's..... Thrust is the same. Basically all the internals are the same.... Ball-bearings don't stand the heat. The Garrett units are water-cooled to keep the life in them.