mx5cartalk.com

Sorry if this has been posted before ..





http://www.bellengineering.net/Pages/intheshop.html

That turbo is at the wrong end of the car.
There are a few kits like that coming out of America, they seem to work but I have my doubts over a traditional turbo in the engine bay style set up. I have seen a Monaro with a similiar sort of set up.
Jake

Now I know nothing about turbos and this setup seems to be a bit of lateral thinking given the lack of space under the NCs bonnet but surely there would be a lot of lag between when you push the go peddle and when the pressure makes it back to the engine.

I remember a few euros did this before hand to improve weight distribution. However, i don't quite understand why the intercooler is mounted in teh rear as well, especially as its right next to the turbo. Isn't that a little counter-intuitive?

DON'T BOTTOM OUT!

Jules

Possibly done as a stealth installation?

Lag would be shocking.

Hmm seen this kinda set up on BMW M5, but I cant see why they want to do it in NC. Other manufacturer managed to do it the normal way...

This type of turbo mounting is used most widely for old American low riders, where they want to keep the engine bay clean and smick, and also for some old classic cars where they want more power, but don't want it to show.

If properly done, the lag is not as bad as you might think. and the heat gets away easily too, but I'd be very worried about bottoming out with this particular installation.

Most of the stealthy turbo installs I've seen mount the turbo somewhere around the middle of the car, tucked up into the chassis somewhere and they generally aren't running intercoolers either as these take up space and make the plumbing much more difficult for a stealthy application.
They are generally only running low boost anyway, so the loss of the intercooler doesn't make too much difference.

From what ive read, there are various positived and negatives with rear mounted turbos. Overall, if engineered and executed properly, they can work ok. And if someone knows how to develop a turbo setup it would be BEGI.

One positive efficiency gain you havent mentioned is that you can retain NA style headers instead of the exhaust gases coming straight out of the block and into a fairly inefficient turbo exhaust manifold. Also the intake piping may be long from a rear mount turbo up to the TB, but this piping may actually work like an intercooler as it disapates some heat from the intake charge.

overall it should be a cheaper setup due to not needing the exhaust manifold - in some applications you don't actually need an intercooler because the increased length of the pipe gives enough surface area for a good amount of the heat to be removed from the intake charge. also the under bonnet temps would be a lot less if not the same as NA. its a good technique when room is an issue. also it will not stress other components as much in the engine bay that where not designed to have that much heat around them - like various pipes and sensors.

There is a thread running in the miata turbo site about this.

http://www.miataturbo.net/forum/showthr ... unt&page=2

Have a look in post #25 on page 2. There is a response from Stephanie from BEGI with regards to the expected final engine bay location for the BEGI NC Turbo kit.

post above mentions intercooler bit in my post - sorry for the double up.

16bit is spot on, the pipe running under the car can get some great air flow, trick would be to design a billet ally headsink pipe like they use in commercial applications.

That way you wouldn't need the rear intercooler and the volume of air between the turbo and the intake wouldn't be much more than the extensive intercooler piping on most cars.