Ruf CTR intercooler placement and efficiency

[jpnovak]

So I have been recently looking at the intercooler placement of the Ruf CTR cars (Yellowbird). The intercooler is placed on the fenderwell section between the engine bay and the fender above the rear longitudinal structure. On a normal 911/930 the electronics console and the oil tank typically are located here.

Let's say that you were running EFI and did not need the electronics console and that you were capable of relocating the oil tank. The oil tank could be forward 72-style (or 964) or smugglers box mounted. relocating these parts gives room for twin turbo mounting near the exhaust valve covers to each side, feeding intercoolers right above them and then directly over into an induction system.

If the intercoolers are mounted there, how efficient are they? The wheel well should have a relatively high pressure under speed. The engine bay has a relatively low pressure due to the cooling fan. One would expect to have plenty of airflow/heat dissipation.

Any real world experience here?

[aschen]

They were fed by vents in the fender right? If so I think it is a good place to put them espescially if they can be ducted in well.


However I think it would be easier and far more effective to do a good Air to water set up with a front mounted rad.

[Slider79SC]

Only the original prototype CTR used fender vents. They (RUF) found that they were not efficient due to the low pressure area passing over the fenders and did not use them on any of the other 29 production cars or the customer converted cars.

They said that there was enough air pressure coming in from the tail to pass airflow through and out into the fender wells. Hence the slotted bumpers on the rest of the CTR's.

Original prototype


Production cars

[Raceboy]

I have looked into this design for some time and planning similar arrangement for my 2.5liter turbo engine as this setup allows for much better weight distribution and less crowded engine bay.
The green car has serial production intercoolers, very nicely packed.

As with all the heat exchangers, the high pressure in the front is not as important as low pressure in the back as air will always find the way TO the intercooler but not that easy out of the engine bay.
With the serial production solution of the CTR, the rear bumper vents create a lower pressure area in the rear fender which sucks air through the intercoolers.

If the air inlet on the fender would be in the front portion of the rear fender not at the top, it would be much more efficient.

[spence88mph]

Would love to see the steel work in the engine compartment with the intercoolers removed. I would love to do this with my car but would never cut steel.

The CTR is my favorite, but it always amazes me why Ruf went to so much trouble with weight, aero, engine etc but used very heavy wheels. Anyway, awesome cars.

[SAY - 642]

[spence88mph]

Thanks a lot mate, I can kinda make it out!

[alwaysflat6s]

A couple of comments:

Actually, there were 29 Ruf vin CTR and another 29 with Porsche vins. Porsche ran out of bare chassis to sell so Alois used existing cars. All were stripped to bare chassis and the only real difference is vin number..and for those who like to collect rather than drive.

ONE other car was built with the top NADA vents per customer request. He wanted a car just like the prototype.

The CTRs were not *quite* as light as has been published... including the prototype [and I am not saying. There have to be a few mysteries in this world.]

The Ruf wheels are rather heavy but incredibly strong and durable. If you look at what happens with most light wheels over the course of time, it makes the case for a heavier but safe wheel with CTR performance.

JR

[alwaysflat6s]

BTW, there is a book on Ruf. There needs to be a book on the CTR!!!

[Slider79SC]

Alwaysflat6,

Great info. I was kinda quoting (sp) off my head using my phone. Forgot about how many non body in white cars they used.

Can you imagine how much the 1 off customer car is worth...... Wow!!!!!