Engine build progress
- Thread starter TTM
- Start date
marcoturbo
New member
Great video... I can't bear those mechanics swearwords [
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TTM
Active member
Just to keep the ball rolling... - Sly's car has performed very well since start up last summer. It has now done about 15k miles and apart from a faulty ground it has not seen any issue. We added a bit of fuel on the map last week while doing some test runs. The bad weather prevented us from testing as long as needed and we haven't quite reached yet the AFR number we are after. - We are slowly getting through the turbo install on Marc's car, and in case you wondered, a Vitesse Stage 3 turbo will fit without grinding the alternator (see pics below). We had to bend the water pipe though and will need to fiddle with the length of the water hose going to the expansion tank. Also, the headlight Iceshark kit adds a lot of wiring in the engine bay, just as if it wasn't already messy enough [8|]
- No progress on my 3.0 apart from closing the oil loop somehow and filling it with oil so it can wait safely until we are done with Marc's car, which is just as well as the bank account hasn't looked too good since Christmas [&:] It's not an easy thing to work quickly and be effective in cold weather - I empathise with professionals who have to do that all week long [&:]
Diver944
Active member
All good things come to those who wait it will be fantastic when you've finished it. There is a register on Rennlist of worldwide Turbo's at 3.0L and over [8D] It's not as exclusive a club as you may think with over 30 completed cars already listed and nearly 10 under construction. It also doesn't include four 3.0L plus cars that I know of in the UK but aren't Rennlist users.
TTM
Active member
Here is an update on Sly's car. A couple of weeks ago we went to a local track in order to do some logs with the Zeitronix wideband and tuning with the Vitesse software. Yours Sincerely began to feel sick at the end of the morning because of watching the screen of the laptop instead of the track - this circuit is a rather short one full of twisty bits, all of it done mostly in 2 gear. Anyway, while the tuning went fine - tuning with the Vitesse software is a doddle - and the car performed very well, we spotted an oil leak in the area of the turbo apparently coming from the compressor housing. We took off the compressor cover and noticed there was no gasket in it - we did not check the turbo when it was purchased (off ebay)...[8|]. As we did not have the sort of gasket needed we put some anti-leak paste. We will see if it cures the problem.
May you be right Paul, may you be right ... We are likely to begin working on my car next week and pull out the 2.5. Really looking forward to get the transplant done.
TTM
Active member
Well, as we run engines with Alusil bores, which are quite sensitive to foreign objects, we feel uncomfortable with using anything else than the stock paper filter and are happy to sacrifice the better flow that could be gained from using a cone filter. Some weeks ago Sly measured vaccum at the entry of the compressor and found out that the airbox without the snorkel was just a bit more restrictive than a cone filter fitted in place of the airbox. With the snorkel he observed that flow was much reduced, so it appears to us that the snorkel is therefore the most restrictive part in the stock set up. (I will try to have him post datas later, he's gone for the weekend). Tape is used for the moment and we will have to think of a cleaner solution later. Just first have to see how it works. As far as optimised snorkels are concerned I got in touch with Jon Milledge in the US who used to make his own ; he doesn't make them anymore as apparently the moulds were destroyed and they were not cost-effective.
sawood12
New member
Well pressure at the inlet of the turbo doesn't tell the whole story. What temperature was the air at the inlet of the turbo? Temperature has a far more profound effect. If the airflow into the turbo is warmer though the restriction is less you could (probably will) be making less power. I think the snorkel is the way to go modified to increase flow as it protects the airflow from the searing underbonnet temps. I've never measured the area of the oval end of the snorkel that attaches to the airbox lid and compared it to the area of the narrowest part of the snorkel hose. I'd like to think that Porsche kept the cross sectional area the same along the length of the snorkel - though it doesn't look that way.
TTM
Active member
Since the set up of airbox + snorkel will obviously allow for cooler intake air than a cone regardless where it's located in the engine bay air temperature is not really a determining factor in this test. You can use a string to estimate the variation of section of the snorkel ; the largest section is where it connects to the airbox, then it decreases dramatically just after the section above the IC-to-intake duct, then decreases a little further to finally end up less than half as large at the other end, which I think makes it incredibly restrictive!
sawood12
New member
I guess the only way to be sure you are getting an improvement in terms of power is to do a back to back dyno comparison. I'd be interested to see some figures if such a test is planned. When I eventually (if ever as babies keep getting in the way) manage to get round to installing a larger turbo I had planned to cut off the circular part of the snorkel and graft on something else with a larger diameter - maybe some sort of flexible smooth bore hose to ensure the snorkel is not a restriction. Or with these new LED side lights you could make duct a flexible hose to a brake cooling duct situated in the redundant sidelight/fog area to ensure you are getting a really cool flow of air. Compressors love cold dense air as it is much easier and more efficient to squash.
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