E30 Zone

240mph in a family saloon

And... alligator skin?!

M5 Jimmy Nail Edition

There's an article on it in the March edition of BMW Car.
What got me is that the turbos are right at the back of the car on the exhaust tailpipes...

I'd rather have this....

http://videos.streetfire.net/search/tur ... c55d88.htm

but that e60 is rather impressive

eh????

gortour wrote:There's an article on it in the March edition of BMW Car.
What got me is that the turbos are right at the back of the car on the exhaust tailpipes...

what?!

munky30 wrote:

gortour wrote:There's an article on it in the March edition of BMW Car.
What got me is that the turbos are right at the back of the car on the exhaust tailpipes...

what?!

+2

That's what it says, pics too. Turbos mounted, one on each side, on the rear tailpipes and piped back to the intercooler under the bonnet.

well thats just silly.

Strange guessing theres not much room in the engine bay

Is Davenotouring about?
Apparantly it's been done before on V-Tec powered Hondas, cos 'the rev-happy nature of the V-Tec helps to overcome the lag caused by having to compress so much air between turbo and intercooler.

munky30 wrote:well thats just silly.

There's obviously method in their madness.

vtec's are sh*te until about 5000rpm so how would that help lag? they're an N/A engine, with lag!

maxfield wrote:

munky30 wrote:well thats just silly.

There's obviously method in their madness.

yeah I guess... just seems to me (with my hugely limited knowledge of engines/turbo's) that all that extra pipe would make it harder for the turbo to do its job. Lots more air to move etc...

munky30 wrote:yeah I guess... just seems to me (with my hugely limited knowledge of engines/turbo's) that all that extra pipe would make it harder for the turbo to do its job. Lots more air to move etc...

I would still guess almost efficient there than on the manifold.

Altho i'm no expert in engineering.

It does suggest that the sheer volume of pipework between turbo and intercooler on the M5 must have consequences in terms of responsiveness.There is also a set of logistic problems with supplying oil and wiring the length of the underside of the car.
But, no worries about custom manifolds, no problem with space under the bonnet, no problem dissipating the heat from the blowers, though a melted back bumper is always a concern.
It won't take high boost pressures though according to the experts, a few psi or 0.5 bar max.
But the engine's internals have not been touched, and the engine has not been apart at all. Still boosts it by 168bhp, taking it to around 675bhp.

gortour wrote:There's an article on it in the March edition of BMW Car.
What got me is that the turbos are right at the back of the car on the exhaust tailpipes...

Gortour is right.

Do you homework people....

Ive seen this car on the web. The turbos are rear mounted, just before th back box.

Believe it or not this has been done for years. Mainly in the u.s of course. To be honest it makes turbo instalation more simple, but its well known that its not the best way of doing it.

A company in the u.s called sts specialise in these rear mounted turbo conversions. Turbo noise is very prominent with thi settup. But i can imagine there will be plenty more lag.

E60 m5 maybe a beast but the e34 m5 has loads more character, would be my choice and the percentage of me owning one in my life time is higher

http://www.m5board.com/vbulletin/attach ... 1172016017

posibly the most stupid set up iv seen in my life but n/m

Is this not quite a common set up for the yanks? Sure I've seen this sort of thing else where....

Perhaps cooling is less of an issue there, esp in West side of USA which is hot a feck all the time!!!

320Touring wrote:I'd rather have this....

http://videos.streetfire.net/search/tur ... c55d88.htm

but that e60 is rather impressive

i'd go for which ever car came with the ac dc soundtrack. oh yeah

744 ft lb torque on the m5?!!! i am way more interested in that than the 800 bhp -
can you imagine what "take of" must be like in that thing?
no wonder they used alligator skin interior= people were getting pressed into the foam seats on the 0-60! had to toughen it up....

I'm not sure if I really understand this rear-mounted turbo stuff but isn't the turbo lag massive? Is this just a dragster or something?

Cheers for putting that pic up HairyScreech.
Not sure everyone believed what I was saying...
I re-read it a few times when I saw it in the mag too...

she's got some poke!

it must be laggy as a bastard, floor the throttle, get out, make a cup of tea and get back in before it comes on boost.

the closer to the exhaust valve the better for a turbo, hot fresh exhust gas is a: moving faster and b:much higer volume.

gortour wrote:There's an article on it in the March edition of BMW Car.
What got me is that the turbos are right at the back of the car on the exhaust tailpipes...

Remote turbos are big in the states. They use the pipework to in effect make the intercooling more efficient. Makes the cooling up to 70 or 80% efficient over 30 odd percent JUST from intercoolers.

They replace the rear mufflers with the turbo chargers as turbos dampen exhaust noise anyway.

There is a You Tube video of a Corvette that has been done. Standard internals, etc 200bhp increase......................and reliable. Apparently. And relatively LAG FREE. YES I did type that.

So kadettc do you know how they get a relatively lag free response from rear-mounted turbos? I've been turning this over in my mind and it just doesn't seem possible.

Given that the turbo boys on the zone go to great lengths to reduce manifold volume ahead of the turbo and given the compressibility of gases I'd have thought you'd be measuring lag with a calendar, or at the very least a dash-mounted sundial.

We need Turbo-Brown et al who understand this stuff to confirm most of our suspicions that this is just about the worst place a turbo could be mounted. Either that or someone's going to have to try it. And it won't be me.

I thinks I'd be more worried about the petrol tank!

Couple of things which make me think that wouldn't be an efficient / lag free setup:

1) Heat in the exhaust gas is what kicks turbos into action and reduces lag and by the time the gas reaches the back of the car, it's pretty cool.
2) Fluids lose energy as they move along pipes. The longer they spend moving in a pipe, the more energy they lose which on a setup like that, will be two fold as the exhaust needs to go miles before it reaches the turbo, and then the charge air needs to travel back again so you probably get quite a pressure drop.
3) Once the exhaust gas has gone through the turbo, it's pretty energyless anyway so just having a great big exhaust system is a pretty efficient way of directing it away from the car. Trying to extract energy from an energyless gas on the basis that having the turbos can exit straight to the tail-pipe seems like a bit of a lame arguement for having them back there to me.

Revealed: 800bhp BMW M5