Ruf BTR and CTR Dyno

[lromanosky]

Hi Guys,
I am finishing the restoration/refurbishment of a couple of Ruf BTR III Motronics, and just had the opportunity to dyno them. Along the way I've also picked up quite a bit of Ruf documentation, and specific information on Ruf CTR #12, which I have the dyno report for when it was new. I've collated all the dyno information, and thought I would share the results, and some observations.

The material that I have to work with is as follows:

1) Dyno of a 1979chassis/1991 factory build RUF BTR III Motronic, 70,000km, done in Calgary, AB with an altitude of about 3,500ft. This car was set up to run .96bar of boost.

2) Dyno of a 1986 chassis/approx 1992/3 conversion to RUF BTR III specs, 70,000km, done in Calgary, AB. This car was dyno's at 1.2. bar boost.

3) Ruf published results for their CTR "Yellowbird" and BTR "1" with CIS injection.

4) Dyno results from #12 RUF CTR "Yellowbird" in 1989 for its original owner.

While I will attempt to make some meaningful observations, this data should only be viewed as approximate, due to the control differences that include, but are not limited to: New vehicle vs. 70,000km and 25year old one, test altitude/humidity/temperature, boost levels, type of dyno etc. etc.


That said, here is the data:

This is the result of a Dyno run done at the Ruf Factory for CTR#12 for the original owner in 1989.

RUF FACTORY (1989)DYNO RUN @ 1.1BAR BOOST
RPM NM TORQUE LB/FT HP Peak Hp Gross
1000 150 110.6 21.1
1500 233 171.7 49.0
2000 355 261.6 99.6
2500 380 280.1 133.3
3000 440 324.3 185.2
3500 500 368.5 245.6
4000 565 416.4 317.1
4500 540 398.0 341.0
5000 555 409.0 389.4
5500 545 401.7 420.6
6000 555 409.0 467.3 500.9
6500 450 331.7 410.5

This is the result of our 1986 Chassis Ruf BTR III conversion, done in Calgary AB (3,500ft) at RTCS.

RUF BTR III MOTRONIC (1986)
RTCS DYNO RUN @ 1.2 BAR BOOST
RPM NM TORQUE LB/FT Hp Wheel Peak Hp Gross
1000 -
1500 -
2000 203.53 150.0 57.1
2500 204.88 151.0 71.9
3000 271.37 200.0 114.2
3500 366.35 270.0 179.9
4000 542.74 400.0 304.6
4500 597.01 440.0 377.0
5000 572.59 422.0 401.8 430.68
5500 474.90 350.0 366.5
6000 427.41 315.0 359.9
6500 339.21 250.0 309.4

This is the result of our 1979 Chassis RUF BTR III Factory built conversion, done at RTCS in Calgary, running .96 Bar boost.

RUF BTR III MOTRONIC BLUE (408HP PUBLISHED)
RTCS DYNO 367HP @ Wheels, 3,500ft above sea level
RPM NM LB FT HP

1000 -
1500 -
2000 203.53 150.0 57.1
2500 230.66 170.0 80.9
3000 271.37 200.0 114.2
3500 379.92 280.0 186.6
4000 542.74 400.0 304.6
4500 515.60 380.0 325.6
5000 495.25 365.0 347.5
5500 474.90 350.0 366.5 392.9
6000 407.06 300.0 342.7
6500 366.35 270.0 334.2

Here is the results of the RUF BTR 1/II CIS engined car, taken from the RUF Brochure.

RUF BTR I/II CIS (374hp DIN PUBLISHED @ .825BAR)
7.2% loss between Gross hp and wheel Hp
RPM NM LB FT HP

1000 405 298.5 56.8
1500 405 298.5 85.2
2000 405 298.5 113.7
2500 405 298.5 142.1
3000 405 298.5 170.5
3500 420 309.5 206.3
4000 460 339.0 258.2
4500 485 357.4 306.3
5000 475 350.1 333.3
5500 452 333.1 348.9 373.97
6000 400 294.8 336.8
6500 350 258.0 319.2

Just a note about the injection systems and the difference between the RUF BTR III and the first couple of versions which were CIS....

CIS is the Bosch injection system that came out in the early 1970's and lasted into well into the 1990's, and was put in everything from Ferrari and Porsche to VW, Mercedes and Rolls Royce. From what I understand it has its limitations after about 400hp, which is why RUF came up with a Motronic (digital engine management) system for the CTR Yellowbird.

There were no road Motonic systems that were adaptable, so RUF took the MP1.2 system which was Bosch's first dedicated Motorsport digital engine management system. It was used on many of the Group B Rally cars and the endurance Sports Racing cars at the time including the Porsche 962 and the Sauber C9. It was also used on the F1 Tag-Turbo engine. The MP1.2 was characterized by dual injectors, with one set coming in with the boost of the Turbo engines. An adapted version was standard on the RUF CTR and a $10,000 option on the BTR.

Observations:

1) Extrapolating from the Data, RUF figures there is 7.2% loss between Gross and wheel HP. At least I think this is right.... If you take the published torque curve, plug the numbers in to the HP/Torque equation you come up 7.2% short of the Hp curve, so I am assuming RUF published the dyno-generated torque numbers, and the Gross HP numbers. I could be wrong on this.

2) The CIS and the Motronic BTR 3.4L engines have very different torque curves, at least comparing the Ruf published data and our Dyno Results. Taken at face value, the CIS injection engine produces much more torque at lower RPM, but quite a bit less in the mid-range. I suppose this makes sense as the CIS system was developed for road cars and the Motronic MP1.2 for racing applications. One caveat, I'm not sure the published flat torque curve BTR CIS showing a minimum of 300lb/ft from 1,000rpm to 6,000rpm is that accurate. I've had a BTR CIS and Motronic, and they didn't feel that different to me.

3) The twin Turbo CTR has roughly 100hp more than the single Turbo BTR both running the same injection system. But both cars have the same displacement, rev range and boost, and the BTR even has more peak Torque. How can this be? The CTR maintains a high level of torque over much more of the rev range than the BTR.

4) Whatever Ruf version and whatever injection system, this is quite a bit more power than a stock 930! These Ruf Turbos can weigh anywhere from between 2,600lbs and 3,000 lbs depending on equipment. I weighed our Blue (1979) Ruf BTR III and it came to 1340kg (2,948lbs) with a full tank of fuel and me in it (180lbs) - so curb weight somewhere around 2,650lbs. That and between 370hp and 400 at the wheels depending on boost levels, more-or-less equals the power to weight ratio of the current Porsche 911 Turbo.

5) A 2017 Porsche Turbo S weighs about 3,600lbs and has 580hp, for a power to weight of 6.2 lb/hp. The Ruf CTR weighs about 2,650lbs and has 500hp for a power to weight of 5.3 lb/hp, and the BTR III running 1.2bar weighs 2,650lbs and has 430hp for a power to weight ratio of 6.16 lb/hp.

In my opinion, these are the greatest road legal 911's ever made!!

[kevin930t]

Do the cars that you are restoring have org.ruf vin numbers?

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[lromanosky]

No, these cars both had Porsche donor cars, and have Porsche Vin's. A Ruf Vin BTR is extremely rare, where as all the CTR's were RUF vin apart from a couple that were retro fitted later. I think that they only made a few Ruf Vin BTR's as press and demonstrator cars, all the rest are conversions; either by the factory or by Ruf authorized dealers of which there were a few of them in the US. My understanding was that Porsche had run out of 911 'body's in white' by the late 1980's, so after the CTR run was done, you didn't have any choice but to start with a donor car. I could be wrong on that though.

Car #1 was converted by the RUF factory in 1991, using a 1979 SC chassis. It is fully documented with all the RUF paperwork. It has a 964 body kit, and we did a colour change from Dark Blue to Maritime Blue. We spent $100k on it, around $45k on new parts. This car is highly spec'd with shaved gutters, CTR 330mm Brakes, Matter roll cage, full RUF instrumentation, Ruf strut brace, Ruf Aero Mirrors, RS interior with Period Recaro RS race seats etc. It is most of the way to being a CTR, but without the twin turbo engine.

Car #2 started life as a Paint To Sample Speed Yellow 1986 Carrera 3.2 and was converted in the early 1990's. It is undocumented and has some non-Ruf parts like the Heigo roll cage and strut brace, Weltmeister suspension parts, period colour matched OZ Racing wheels, 964 RS rear wing, 964 body kit, etc. It does have a genuine Porsche 964 RS 'Rubystone' interior in Purple and Mauve that is very 1990's.

The Maritime Blue car has just been finished after a 3 year rebuild, and the Speed Yellow car is almost done, but is going back in the shop because I wasn't happy with the gearbox (noisy first gear) so it is getting the gearbox rebuilt. I was still able to dyno it though.

I've done several videos of the Maritime Blue Run that are on Youtube, if you search RUF and Lawrence Romanosky lots comes up. I'll post some photos.

Cheers,

[smurfbus]

Thanks for the intersting info on the engines and dyno numbers.

[brcorp]

Pictures always work better for me.....

Added a couple of addition reference points

[lromanosky]

Yes you are right the graphs are better!

Should one of the graphs be the CTR, or did you just do the BTR's?

It is hard to make direct comparisons because we are comparing Marketing-driven published figures in a sales catalogue, A Ruf dyno run done in 1989 on a new car in Germany, and a couple of Dyno runs done in Calgary, AB which has an altitude of 3,500ft, along with the additional results that you've brought.

I've learned that the cars are quite sensitive to heat soak, as there is no easy way to replicate 100mph airflow over the car which is necessary to keep the engine cool and the intercooler doing its job.




But there are some interesting questions/points?

1) it looks like the Ruf published torque curve for the CIS BTR 1/2 that shows a flat torque curve from 1,000 rpm is overestimating that cars flexibility. I've owned one, and it didn't feel like anything was happening beneath 3,000rpm, and which is the same for every other BTR on the graph. But it is possible that the published HP and Torque curves are from an engine dyno??

The Dyno report that I have for the CTR shows the vehicle corner weights and a bunch of atmospheric information so I assume that is done on a rolling road. That said the same brochure shows the hp/torque curves for the BTR and the CTR, and shows an almost perfectly straight torque curve for the BTR, whilst the CTR sloped considerably. I don't think the CIS BTR 1/2 torque curve is correct.

2) I would be interested the spec/modifications done to the cars with higher hp and flatter torque curves after 4,000rpm, where the stock single turbo Ruf tapers off...

Thanks for posting...

[kevin930t]

There is a guy out of Alberta that has restored a few Btrs,from what i have seen he has done a fairly good job.I think his name is Laurence.

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[lromanosky]

Well the 'L' in lromanosky is Lawrence and I am in Calgary

[Mocker]

So you're saying you know him?

[SAY - 642]

Thanx for sharing the data, Lawrence. Very informative

[kevin930t]

Maybe you can get in touch with the Lawrence in Alberta as he is very familiar with ruf.I know he owned a few that he had restored.If you ever go on u-tube he has documented a couple btr.He is a funny looking fellow and he might be light in the loafers but he really has a ton of great info.Btw welcome to this great forum.

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[lromanosky]

Happily one of my favorite things to do is take a Ruf out for a drive and do a video! I regret having to leave most of the footage on my computer though!

Not sure if anybody will be interested in this, but my interest in Ruf started in 2010. Of course I had read about RUF, and Porsche Turbos since I was a kid, but I had never had any direct experience with them.

I was working at Distinctive Collection, which was Calgary's dealer for Aston Martin, Bentley and Spyker (at the time). I put together a deal with a guy in Victoria who had a bunch of nice cars including a 1994 3.6 Turbo and the RUF. I sold him a DBS, but the only way I could make the deal work was to take the RUF on trade, and then buy it personally - the dealership didn't know what it was and wanted nothing to do with it.

I knew a bit about it, and it sounded cool, but I had never even driven a Porsche Turbo before let alone a RUF.

So I fly into Vancouver to pick up the car after the PPI checked out, and drive it back to Calgary. Not really knowing what to expect, apart from the previous owner telling me the car was a total Monster. The car was a 1985 Porsche Turbo taken to Scottsdale Motorsport (a Ruf Dealer) in the late 1980's and converted to a BTR.

So I pull out into traffic, and the gearbox is a bit recalcitrant and it turns out needed a first gear, and the clutch was extremely stiff, and the car had a stupid sound system from the 80's that send feedback through the speakers and the car was basically very grumpy. I'm not sure what I've done.

The traffic thins, I merge onto the highway and floor it. The boost gauge snaps to 1.5 bar and the car just explodes forward. Holy Crap! I've driven lots of fast cars with 500-600hp, but this thing was at a completely different level. I figured that it just couldn't be right though. I had no experience with tuned turbo engines, no idea what boost was appropriate, but I knew that 1.5 bar was too much. The car just seemed completely out of control. So I figured that I would try to keep the boost to 1.2bar, but the boost control didn't work. The wastegate had frozen shut!

Anyway, I took the #3 back to Calgary, avoiding the Transcanada, the whole way trying to manage this beast that I bought. I had never felt anything like it. Passing cars was like a video game. I would pull out, hit the boost, and be doubling the speed limit, then hit the brakes still in the passing lane, so I could shed enough speed to get back in my lane. I got the car home in one piece though it was leaking and smoking (oil on the manifolds) so bad it filled my garage full of smoke. Sitting there like a smoldering dragon!!

Anyway the 1000km drive was forever etched in my mind, and that started me vacuuming up anything RUF that I could find. The only other car/drive to equal that was one in a 997 GT2RS which was similarly unhinged. I have a file on my computer that says "DO NOT UPLOAD EVER"....

[lromanosky]

Hi Guys,

I've finally written the description and put the BTR on eBay....

https://www.ebay.com/itm/253362606603

It has a 4,500 word description, references a 8 part video on youtube, and has 375 photos on Flickr. I think this maybe an eBay record for longest description!

Cheers,
Lawrence Romanosky
Calgary, Canada

[Carbster09]

Great story! Thanks, made my boring day less so ... now more than ever looking forward to getting my boosted 930 back! Oh it has a Ruf front end, bigger K27, 1.2b and a few mods ... supposedly done by Ruf in Germany before it was shipped to the US. At least that is the story I have been told.

[lromanosky]

Here is a comparison between the BTR and a stock 930...
cheers,

[Eric at Pelican Parts]

Originally Posted by lromanosky

Here is a comparison between the BTR and a stock 930...
cheers,

That's an awesome video there, very informative! Thanks for taking the time to make it!

[lromanosky]

Thanks guys; I think these cars are under-appreciated relative to the other 911 variants out there.
Cheers,

[alwaysflat6s]

Long time Ruf fan. Enjoyed. I note your eBay auction has already ended?

[lromanosky]

I just re-listed it..
https://www.ebay.com/itm/253383826156

Cheers, LR

[krasuskyp]

Welcome, Lawrence and thanks for sharing your insight and experiences.

And, heh... my kinda nutcase with the do not upload file... I know nuthhhhhing...


We do love pics 8-)