Ruf-Racer

I am not sure at all about details. I am also not too clear on the differences between 'conversion' and my facotry Ruf VIN model. I do know that I need to run through the gears several times to switch to 'fierce' mode! I always run through the 4500-6500 range in third,fourth,fifth and top gear on the practice road.BTW,I have no boost gauge. I don't know how much power I have either. Alois tells me I am running close to the limits of my P Zero tires and that is good enough. He did send a letter from the Ruf Team acknowledging our performance and speeds which have exceeded the R&T High Speed Shootout efforts. Bill, you have the IRC too?Want to run at Battle Mountain Nevada late July? Mail me!

R <img src="graemlins/jumper.gif" border="0" alt="[jumper]" />

TB993tt

Bill
Twin plug, GT2EVO conrods + head sealing + 2 oil big coolers help make the high boost safe but the high boost is only in the mid range, typically it will drop to around 0.95bar at peak power before rising again to 1.05bar ish towards the limiter. The Ruf boost curve seemed to me to rise approaching peak power. I have mentioned to R before that the car I rode in had 1.1bar at peak power and gave 540hp (flywheel) on a dynojet - but didn't have the massive mid range of my motor -seem to be different approaches in mapping, apparently in the lighter 993GT2 cars, RS build and map the engines to deliver the torque higher up @ 5200rpm and give more peak power of around 540hp, but for the heavier 993tt prefer to major on the lower end (boost) torque which presumably leads to reaching the knock limits early on in the rev range resulting in backing off of the boost and hence limiting peak power. I know that RS give the option of running the GT2EVO intercooler and convert to pressure sensing induction and can get 570hp from my set up -so it looks like it is boost air temp which is the limiting factor.

Ruf-Racer

Hmm.Very interesting since Alois was very firm about my not upgrading my IC! He said 'Roland-no do not do that'and offered no reason!i thought the bigger IC was a good idea for my application which requires many miles of high boost!

R

Bill S.

The intercooler issue is a bit complex. Ruf has told me that they have tested many intercoolers for the 993 Turbo R and only the "big thin" one on the factory 993 GT2 made a difference. Most of the other intercoolers either made no difference or made horsepower and/or throttle response decrease. I think several factors come into the intercooler equation. Some being the material the intercooler is made from, its coating, how much air you can pass through it, it's thickness, overall surface area, how it's "tuned" to the engine's intake air flow, etc. I think even if the intake manifold air is proven to be cooler with one intercooler over another (which some really do), you still need to consider the other factors (e.g., throttle response with a very large intercooler may suffer). Look what the factory and Ruf have done on the newer cars (and the old 959 and Ferrari F40). Separate intercoolers placed in the rear fenders where air passes through them much better than the 993 TT can do, even with a GT2 spoiler. Personally, I think you'll need to try an intercooler for yourself to confirm Ruf's test results. It's always interesting to see some of the big intercoolers that people use in the 993 TT and 930s. Many don't consider airflow through the intercooler. I've seen many 993 TT and 930 intercoolers with no sealing with the car's body. With this, outside air would pass around the intercooler (less resistance), rather than through it.

ZCAT3

The IC issue seems to be a no answer deal. Steve Weiner at Rennsport in Portland adamantly recommends the Cargraphic IC when using GT-1/GT-2 turbos. Andial recommends this as well. RUF, on the other hand, obviously does not agree. I am running a Cargraphic IC on my modified TT and also have the stock IC. I did not notice a big difference between the two other than I seemed to reach full boost quicker and held it better with the Cargraphic IC. I have not dyno tested it or done any other tests. My reason for the larger IC was basically insurance that the engine longevity not be compromised. But as RUF says this is not necessary I am rethinking this.

As for sealing the IC against the lid, if you look at many Porsche race turbo applications (several are shown in Bruce Anderson's book), you will see that the factory race cars never seem to have a rubber seal - the ICs are just bare metal.

Bill S.

Although the intercoolers are bare metal, the body usually has the rubber seal. It's usually easier to mount a rubber seal to the body sheet metal than the intercooler. Then you don't have to manufacture the separate housing that's used on the 993 TT. Take a look at the 993 TT, 996 TT and a 959. There's quit a bit of engineering in making an airtight seal around the intercooler. The big front oil cooler on the 993 TT and the extra one on the Ruf car also seals against the bumper for the same reason. In fact, I think getting the oil temperature down also helps prevent detonation, just like the IC. Maybe Ruf decided this was the way to go since he already had the air flow available in the front bumper. He does not use the Turbo S oil cooler. He adds a big one to the driver's side front fender with a fan, sealed to the inside bumper with rubber.

TB993tt

I have been discussing the I/C issue with Pram off line and would ask you look at this link:
<a href="http://www.autospeed.com/A_0527/P_2/article.html" target="_blank">http://www.autospeed.com/A_0527/P_2/article.html</a>

I am fairly convinced that on a road car the I/C does act like a heat sink and that shrouding the I/C is not necessary make it work better. Yes Porsche shroud (very effectively) the stock I/C and its efficiency is very high -so high that as Ruf apparently says above and also RS Tuning, that there is not a more efficient unit on the market (they have not tested the Andial)
I run the Cragraphic/FVD/TTP I/c on my motor and RS tested it during dyno calibration and full power tuning -they shroud it tighly and force air through the cores at a set speed. No better than stock apparently. On the road I run without shrouding and the big tanks on either end + the high surface area in the join in the middle are all exposed to extra air flow, this together with the increased surface area inside the whole unit I reckon makes the I/C a big heat sink which for road driving full boost squirts gives more power than stock. I believe I can feel this and also feel the power drop off if it is run fairly continuously on boost (quite a hard thing to do). Non of this helps Roland who needs an I/C to work the way its supposed to.
Any thoughts on this ?
The GT2 EVO unit is made by a company called Secan in France and they are $15000, also you have to change to pressure sensing induction. I think for the Ruf Turbo R this I/C is a bit big since it is made for the GT1 turbos or bigger K26 units with separate wastegates.

Ruf-Racer

I believe a simple model could be devised to measure the T/R of the IC. My instinctive thoughts are that the IC is indeed a heatsink! For my application the solutions resides in mechanizing an IC with a very small thermal resistance.Perhaps a liquid cooled case with copper infrastructure.I can testify about the effectiveness of copper as a heatsink for cooling active devices!I sure would love to work on such a project!

Bill S.

I agree that the IC works, in part, like a heatsink. However, once you have established that the IC is really cooling the intake air better than stock (which a temp probe has shown on some large ICs), then you might ask the following questions:

1. Does the "heatsink" cool down faster with rubber seals added around the edges?

2. Does the larger IC increase turbo lag?

3. Does the larger IC interfere with the intake airflow if it's not tuned to the engine?

Remember that the air passing through the IC probably touches the internal fins more than any other part of the IC. I think you would want these fins as cold as possible. Certainly forcing outside air through these fins will help keep them cool, stock or not.

ADOGNY

I stuffed several bags of ice in my stock I/C and found it out performed any other I/C's out there on the market. And it only cost me $3.49 to do it!

pig4bill

[quote]Originally posted by ADOGNY:
<strong>I stuffed several bags of ice in my stock I/C and found it out performed any other I/C's out there on the market. And it only cost me $3.49 to do it!</strong><hr></blockquote>

If you really want a cool intercooler, I've heard of the Japanese turbo guys that are running n2o positioning the purge valves next to the intercooler. When they purge the nitrous system (I guess when they stage in the lights) the i/c gets a shot of sub-zero gas. It doesn't last long, but every little bit helps in a drag race. I've seen talk of rigging up n2o nozzles to cool the i/c!

Bill S.

It's good to hear people thinking about how to cool the compressed air. I think many more inventions are possible in this area (maybe even using an A/C cooling element with the "IC A/C compressor" run off the wheels) Maybe we should start another topic "Cooling the Compressed Air on a 993TT". Getting back to this topic, I have a few things to add from feedback I got from Ruf:

1. For fastest acceleration, you should shift at the first interruption of the rev limiter.
2. Using 7200 RPM is safe (no time limit specified).
3. All 993 Turbo R's has the same performance, independent of whether it was done by Ruf at his factory (i.e., a car with a Ruf VIN) or a Turbo R conversion by a Ruf technician in the U.S. or another country.

TB993tt

Bill S
I dug up those dyno figures from 911 & Porsche World September 1998. The car was a UK model RHD which had the full engine/suspension and wheels package.
2000 104 bhp 267 lb/ft
2500 182 375
3000 235 404
3500 279 411
4000 348 449
4500 466 535
5000 506 523
5500 499 468
6000 460 395

Like I said before I have seen another turbo R give 537 hp on a dynojet at 6500 whereas the one above looks like the power is dropping off - so are all turbo R's the same ?
What is interesting is that Mr Ruf apparently was very unhappy about the above figures being published -one can see why, as it is easy to get hung up over "why can my car not have the 537hp that car has".

ADOGNY

We are forgetting that these cars are hand built as well. I have been told that from the factory there are HUGE differences in performance from car to car. A local tuner near me DYNO's his cars before and after the mods, and he told me he has seen stock cars with HP numbers varying from 380's to 420's! I wonder if these factors would carry over into some of the other modifications and that is why there are differences. Also, who knows where they tested these cars and what the weather conditions were like. I would imagine also a car tested in 40-50 degree weather would run stronger than one tested in 90+ degrees. So many variables - who the hell knows!

Adam

Bill S.

Thanks for the figures. I agree that there are many variables. However, I think that two Turbo R engines, given all other variables are the same, will match each other very closely. I think the biggest variables are the ambient air temperature, fuel octane, and especially the ECU. Ruf's "smart" ECU programming may be the biggest reason he dislikes seeing the numbers published. Here's an example. When I went on a long road trip with a Viper RT/10, it seemed that on the straights the Turbo R was not that much faster than the 450 HP kit. She was obviously proud that her Viper could stay withing 3-4 cars lengths. However, as we did more tests over the course of the trip, the car definitely got faster. After about 45 minutes into the trip, she was very disappointed that her Viper was now 6-7 car lengths behind. The Turbo R would clearly pull away, and I could feel much stronger acceleration. I know this sounds odd, but I'm fairly certain we didn't imagine it. It seems Roland, who has had the car longer than me, is seeing the same thing. The car seems to become a different animal after it's "trained" a bit. I would guess that some dyno tests may not have given the car the octane, temperature, and "training" where it performs best. I think this "smart ECU" is causing most of the mystery behind the Turbo R since most other ECU's give nearly maximum power right away. I would guess Ruf's 490 HP rating is "worst case", assuming 98 RON, "typical" temperature, and "typical" training.