Upgrading 1989 Porsche 930 RUF BTR Conversion

[donau]

I am in the process of upgrading my car and have been delayed by wait-times for the different parts. But now that I noticed this special section for modifications with nothing in it so far, I thought I'd start my thread even though I'm not finished yet.

Part of the reason for the longer than expected completion time is that as I've gone along, I've realized some new needs that needed taking care of - and as a consequence, new parts were needed.

The latest, and hopefully the last item for this first phase of upgrades, is B&B exhaust headers that I have been waiting for for the last 3 weeks.

The whole project started with me learning about the latest and the greatest turbos available for the 930s. I was reading about the Borg-Warner KKK based K27 HighFlow S turbo that is a hybrid turbo, reducing turbo lag by about 300 rpm and increasing the top end boost to that exceeding K29 performance levels due to tighter compressor housing, I believe the compressor wheel is one from one of the Garrett turbos. Also part of the design is a 3 inch inlet and venturi to decrease spool time by increasing velocity across the inlet. And the K27 HFS is supposed to be able to support 550hp. This by no means is an indication of how much hp my car will have.

So, shorter spool time, more top end power, to that matching or exceeding the K29, which is a big turbo, sounded good to me. Especially knowing that my old K27 cast unit that RUF used almost 20 years ago, probably has some issues with pin holes causing leaks etc.

So, I went ahead and ordered the turbo. Then I started thinking that by the same logic (and the fact that I also had read about it) the OEM unit is cast. They say by now 80% of those stock wastegates have pinholes due to condensation caused rust. They are put together like a valve with a guide and valve. In time that guide wears and moisture rusts the cast bottom.

In other words they don't hold air either and so they bleed. So, which Wastegate should I buy? The most popular amongst the Porsche enthusiasts seems to be the Tial 46mm. Apparently the Tial can flow alot of air and therefore will not allow boost creep, therefore keeping you at a more accurate boost level which equals more power, less lag & more reliability. But mainly reliability. And that's a good thing.

So, I ordered a Tial 46mm as well.

At the same time I was learning about the required air to fuel ratios for the various types engine uses: cold and warm idling, cruising and boost. It soon became evident to me that the required level of fuel flow for the boost in the new turbo was in question with my standard Euro Fuel Distributor. So, I also ordered an Imagine Auto modified Euro Fuel head that flows about 20% more fuel than the stock one.

Now, who's going to tune this new setup? Me of course! How would I know how to do that? Get an AFR display unit and an adjustable Warm Up regulator (I had a spare one, why? that's a different story). So, I selected an AFR display that fit nicely in a slot that's probably meant for putting your sunglasses and such. It's in the center console at the bottom part. The one from Western Motor Sports did the job nicely. I also sent my spare WUR to a guy in San Diego who makes them adjustable, for cold, warm and boost all individually and separately. The CO seems easy enough to adjust. Just an allen key and turn it.Of course you have to know where - a shaft sticking up conspicuosly next to the fuel head.

And two more late thoughts:

1. Will the new turbo get enough air flow from my stock headers? Oh my gosh - Probably not! So, I ordered the B&B headers that are sure to provide for a nicely rounded setup with sufficient flow, and according to advertizement, reducing spooltime by up to 800 rpm. I won't mention the advertized hp increases yet since I will want to dyno the car and I will then post the real RWHP that the car produces. So, the total reduction in spooltime should be about 1100 rpm. That would mean full boost at 2000 - 2500 rpm range, and best of all, continuing up till redline.

2. Another late discovery was the fact that the RUF design had eliminated the Blow-Off-Valve plenum setup, and had not replaced it with anything. This is clearly a shortcoming in the design. To cut a long story short, I ordered a billet diverter valve that will recirculate the air in between the shifts reducing back pressure to the turbo. Apparently, over time this could damage the compressor wheel. I already received the Diverter Valve.

Almost forgot, one more thing: One of the previous owners of this car must have removed the boost control setup (probably to use in their new car) and this car was left with a 1 bar spring in the wastegate, which seems to be the way most 930 owners run their cars actually.

So, I had to order this gadget from RUF. I already received it.

OK, so that's quite a couple of new items ordered. Who's going to put them in? First thought: ME!

I started by installing the adjustable WUR and the fuel head. Not being a mechanic and not really having had a lot of experience doing stuff like this, this turned out to be quite a task. For example, changing the fuel filter which was a pre-requisite for the new fuel head, was an unexpectedly unpleasant job. Took me many hours to do just that. I won't tell how many in order to be spared embarrassment.

Anyhow, the fuel head and the adjustable WUR (and the fuel filter) are in now and the car is going great. The WMS AFR display is also in and connected to the lambda control and the Bosch LSU 4.2 sensor.

For installing the turbo, and the headers, I have decided to let an excellent local outfit called CARR Industries do the job.

I'll attach some pictures here and when you see the header bolts you'll understand why I rather let someone else tackle those - on their backs under the car!! Just waiting for that bad boy to fall on his face.

OK, in the hopes that this long story is not getting boring, I'll attach a few pictures here, with short comments:

Here's the boost control gadget with it's support rack, and the diverter valve already connected to the large diameter elbow going into the air flow housing.
In the background, on my laptop screen: NevadaJack replying to Roberto
The big spring will be crammed into the Tial wastegate.





The Fuel Filter on the left side next to the black permatune box:
(Of course the Intercooler and airbox have been removed in this picture)



The K27 HFS:



The new fuel head:



The Tial 46mm wastegate:

[donau]

The old headers to be replaced by the B&B unit once I get it:
(Note on the right hand side the dirty black area: thats oil leaking, forgot to mention that I am getting new valve cover as well to stop the leaking)

Attachment 335

The adjustable Warm Up Regulator:



The WMS AFR display:

[donau]

I will continue this thread as there will be progress on my car.

[Centurion]

Nice read. It looks like you are a real gearhead. I would love to own a 911 like the 912 and mod it to suit my needs and liking. Are going to do any suspension, chassi or break mods so that the car can cope with all the amount of power which will be delevoped.
Do you have picture of any of your older or current projects?

[donau]

Nice read. It looks like you are a real gearhead. I would love to own a 911 like the 912 and mod it to suit my needs and liking. Are going to do any suspension, chassi or break mods so that the car can cope with all the amount of power which will be delevoped.
Do you have picture of any of your older or current projects?

Thanks Luwalira! As for breaks, I've got the big reds already. They came with the car:



One of my goals is to make sure that the car will remain as "RUF" as possible.
Therefore for the suspension, I just want to verify (with my own eyes - which I have not done yet) that the car has the Bilstein gas filled shocks, anti-roll bar and McPherson struts among a few other things that the RUFs were supposed to have. If any one of those items is missing or different, I am planning on having them installed.

But my next project will definitely be the following:

This car has the G50/50 transmission which is generally considered superior to the 5 speed that RUF used for converting the pre-1989 cars that had a 4-speed in them. With the introduction of the G50/50 transmission, for SOME of their 1989 conversions, they took the G50/50 and made a 6 speed out of it.

I have already asked RUF to let me have the first one that they come across. I have also entertained an idea of letting them convert my G50/50. But then again, would be nice to have a spare transmission

As for pictures: when I initially introduced this car on this forum in the My cars - section, I had posted quite a few pics of it. Then as the need arose for me to post pics for other threads later on, I ran out of space and had to delete all of those pics. When this project is finished, I will post another set of pictures, which of course means that the ones I posted today will have to go.

The items that make this a RUF BTR by the way are mainly the Group B cams (RUF spec) and the 3.4 cylinders and 98mm pistons (instead of the stock 3.3).
Also, the weight of the car is reduced to 1256kg (~2763lb) mainly by using different materials on the engine lid and the bumpers I believe, as well as some other items. It's also got a RUF longneck Intercooler and the RUF exhaust setup.

It's supposed to have all those special suspension items too, but as I said, that's one thing I have not verified yet. If not, then yes, that's part of the next project.

And then of course there's all the cosmetic stuff that is RUF: The steering wheel, The wheels, the gauges, and now I've also ordered the RUF gas, break and clutch pedals just for my own satisfaction.

[bmwrules]

I'm looking forward to you giving me a ride in it once you get all the work done. Just don't kill me in the process. I loved how it sounded before. I wonder how much these new parts will change the sound, if at all.

[Carbon]

Just make sure you have what's appropriate for the car (blow-off valve or recirculating valve). Also, if you're not very experienced as a mechanic or with installing things like this, I'd at least get some help (if not have a professional shop do it) to prevent potential issues as a result of installation problems. I know part of the experience for you is probably the mechanics of the parts, though.

[donau]

I'm looking forward to you giving me a ride in it once you get all the work done. Just don't kill me in the process. I loved how it sounded before. I wonder how much these new parts will change the sound, if at all.

Thanks bmwrules We'll definitely drive it somewhere safe. I've been thinking about that sound issue myself and also hope it doesn't change. Hopefully it won't since it's still got the same RUF exhaust system with the same mufflers. We'll find out one of these days - soon I hope.

[donau]

Just make sure you have what's appropriate for the car (blow-off valve or recirculating valve). Also, if you're not very experienced as a mechanic or with installing things like this, I'd at least get some help (if not have a professional shop do it) to prevent potential issues as a result of installation problems. I know part of the experience for you is probably the mechanics of the parts, though.

Thanks Carbon! yes, the billet diverter valve is a recirculating valve and that should be taking care of the issue of the sudden back-pressures that have nowhere to go except back to the compressor housing, causing friction to the blades etc. It's interesting how a project like this, where the original idea was just to replace the turbo, snowballs because of all the interdependencies etc. And as for the recirculating valve, absolutely necessary since I don't want any damage to the new turbo because of some back-pressure issue resulting for example from an abrupt closing of the throttle.
And you are absolutely right about the professional help. The last thing I want to do is spend all this money for all these parts and then screw it up because I wasn't skilled enough to do the job properly. That is why I have decided to let CARR Industries do the job. There is a very multi-talented individual who knows these cars inside and out and is the perfect person to do the turbo/headers/wastegate - job. And also the Boost control and the diverting valve as well as the valve covers.
But you also hit the nail on the head with the statement about me wanting to experiencie this job myself. Absolutely true. This is half of being the Porsche enthusiast to know exactly what is where and how it functions and what is involved in installing a specific piece or fixing it. That's just as exciting as the driving part.
But fortunately I have now done enough myself to get a feel of what it really means to get some bolts that are stuck loose without breaking anything and so forth. I also know enough about doing the rest of the job that I could do it if I was OK with taking a very long time doing it. And I am a bit impatient. Rather let someone who is used to doing it do it quick and then let me enjoy it. In this case it will be good enough for me to just know how its done.

[Carbon]

Cool. I look forward to hearing how it will turn out. How is a car like that with all that power and the engine at the rear wheels?

[donau]

Cool. I look forward to hearing how it will turn out. How is a car like that with all that power and the engine at the rear wheels?

To be pushed through space so fast has probably the same effect as drugs, the rush is so addictive that it is unreal. It feels very different from the other modern fast cars. Getting a big kick in the pants and being pushed through space very fast is the only way I can describe it.

[donau]

I will continue this thread as there will be progress on my car.

After a 5 week wait I finally received my new B&B headers and the car is at the shop still being worked on. The latest twist is that my exhaust system did not fit the new setup so I had to order a new one, a stainless steel dual tip Fabspeed system and overnight it. I hope that will be the end of the snowballing additions. I took a few pictures when I stopped by the shop today, due to space limitations I'll attach two of them here. I quite like the bling effect even though no cleaning has been done yet. Even the Imagine Auto valve covers look brilliant to me, even if I say so myself. Too bad nobody will ever see this setup under the car once the car is in operation again.

BTW, checked the suspension and it's got the bilsteins etc. that the stock 930s did not have and therefore the car's suspension is also according to RUF spec, at least according to the Marc Bongers' "Porsche and RUF-Sportscars" - book.

[bum-man]

Finally discovered this thread!
Wow that's a beaut, there's just something about elaborate exhaust work that makes an engine look appealing.
Did you ever get a dyno before you started the modifications, that would be pretty cool just to see what you would come up with afterwards.
Looking forward to the finished product.

[donau]

Finally discovered this thread!
Wow that's a beaut, there's just something about elaborate exhaust work that makes an engine look appealing.
Did you ever get a dyno before you started the modifications, that would be pretty cool just to see what you would come up with afterwards.
Looking forward to the finished product.

Thanks bum-man Regarding the pre-mod dyno, I was considering it but in the end did not do it. The published hp number for this car was 374hp at 0.8 bar. The car had a 1 bar spring which would have upped that number by a bit. I was told by someone at RUF that they have always been conservative with their numbers. I'm fairly confident that the car before the modifications was around 400hp. In fact the person at RUF mentioned a number slightly above that. But in my mind it was a 400 hp car with the 1 bar spring. It will probably be at least a month before I'll go to the dyno since I need to break that turbo in for about 500 miles or so.

[bmwrules]

That 400hp is really good considering the fact that your car is lighter than the last couple generations of 911 turbos. I know you've told me before on the phone but can you remind me how much it weighs. Wasn't it something like 2700-2800 pounds?