GT4EC - The GT-Four Enthusiasts Club

General Category => The Chill Out Room => Topic started by: bazza2541 on October 22, 2008, 11:43:11 pm

Title: I may be mad..........
Post by: bazza2541 on October 22, 2008, 11:43:11 pm
I was thinking about the engine in my 165 and what to do with the one I bought off Paul when I had an idear.
I want to use a holset HX35 but there isn't enough room, so hows about mounting it behind the back bumper?
Title: Re: I may be mad..........
Post by: paul_gt4 on October 22, 2008, 11:44:40 pm
you've more money than sense
Title: Re: I may be mad..........
Post by: bazza2541 on October 22, 2008, 11:45:26 pm
They do it in Yankeeland to those corvette-thingys.
Title: Re: I may be mad..........
Post by: bazza2541 on October 22, 2008, 11:46:45 pm
The way I sees it, the exhaust gasses will be cooled down a good bit by the time they reach the turbine and so won't meltify the diesel turbo?
Title: Re: I may be mad..........
Post by: bazza2541 on October 22, 2008, 11:49:04 pm
Like this (a bit)

(http://www.turbochargers.com/store/images/c6-kit.jpg)
Title: Re: I may be mad..........
Post by: bazza2541 on October 22, 2008, 11:53:02 pm
And if I fuel it with LPG, I can run a 12.1 CR.
Title: Re: I may be mad..........
Post by: bazza2541 on October 22, 2008, 11:56:26 pm
On the plus side you get
*Reduced under bonnet  temperatures.
*Cooling effect of under-car airflow on exhaust gasses.
*Cooling effect of under-car airflow on oil pipes.
*Marginally increased turbo lag (hopefully).
*Cooler running turbo.

On the minus side you get
*Nuthin comes to mind.
Title: Re: I may be mad..........
Post by: paul_gt4 on October 22, 2008, 11:59:44 pm
guy in the states done that style of set up on a new M5 with mad power, that would be some serious work and a serious amount of cash to fund it
Title: Re: I may be mad..........
Post by: bazza2541 on October 23, 2008, 12:02:18 am
Nah, it would need some lengthened oil feed and return lines, longer intercooler piping and some mounting brackets. Those lorry turbos are cheap as chips.
Title: Re: I may be mad..........
Post by: nev520 on October 23, 2008, 09:55:56 am
go for it matey, i can't wait to see the finished beast 8)
Title: Re: I may be mad..........
Post by: flyingtele on October 23, 2008, 10:00:35 am
yes, the idea of the rear mounted turbo is intriguing. would definitely prolong the life of the tubby but serious lag could be an issue
Title: Re: I may be mad..........
Post by: peterp1per on October 23, 2008, 09:41:51 pm
how does the oil return work on a setup like that?

i always thought that a minimum 30 degrees angle of the dangle was needed between the tubby drain and the sump?

being gravity drained the oil wont run along horizontal lines all the way to the engine?
Title: Re: I may be mad..........
Post by: paul_gt4 on October 23, 2008, 09:44:41 pm
probably an inline feed and return pump could settle that issue peter
Title: Re: I may be mad..........
Post by: bazza2541 on October 23, 2008, 11:24:47 pm
probably an inline feed and return pump could settle that issue peter

Yeah a supplementary pump is the way to go, acts like a turbo timer too.
Title: Re: I may be mad..........
Post by: paul_gt4 on October 24, 2008, 12:58:52 am
http://www.ststurbo.com/ (http://www.ststurbo.com/)

have a look here, might help you with a few ideas
Title: Re: I may be mad..........
Post by: Coyoteboy on November 07, 2008, 01:43:32 pm
Pros:
Cooler underbonnet.
More space underbonnet.
cons:
Lots of extra pipework
Extra lag problems
Where's your IC going?
Impact from ground objects?
Turbos work most efficiently when using the uber-hot gases from the exhaust port - they work by extracting the heat energy. You need the whole length of the cars exhaust to be sealed perfectly as any loss before the turbo will hurt power further.
Oil drain I cant see being a problem providing it is kept above sump height and the exit pressure is lower than the intake pressure by some way. A small pump would sort it otherwise.
Large water/oil mass in the hoses to the rear of the car.

Seems like more cons than pros to me, but it woudl be interesting!
Title: Re: I may be mad..........
Post by: bazza2541 on November 07, 2008, 02:28:43 pm
Lag is not an issue.
IC will be going behind the bumper.
Surely its the exhaust gas flow that turns the turbine, not heat?
Oil supply is not an issue either.
Title: Re: I may be mad..........
Post by: Coyoteboy on November 07, 2008, 05:31:00 pm
Its not quite as simple as having teh same flowrate at each end of the exhaust so the turbo can go anywhere, the turbo extracts the kinetic energy of the gas. As the gas flows down the exhaust it cools and slows, losing energy as it goes due to the cooling. This loss of energy is what you'll be wasting by placing the tubby at the cold end.
Title: Re: I may be mad..........
Post by: bazza2541 on November 07, 2008, 05:33:16 pm
I think I can risk it. I can't find anywhere else to fit my chosen turbo.
Title: Re: I may be mad..........
Post by: Coyoteboy on November 07, 2008, 05:36:47 pm
It'll be good to see it working, keep us updated!
Thats the sort of thing you're thinking?
Buy lots of lagging!
(http://images.paultan.org/uploads/2007/02/bmw_m5_twin_turbo_7.jpg)