Contour Enthusiasts Group Archives Forums Modifications Duratec Performance Twin Turbo?

Porsche is not Ford... true, but the Duratec engine was developped by Porsche.
Sorry just had to throw that in.
-Mark

You're dealing with larger displacement on those engines. That means you need to be able to deal with more exhaust gases andstill be able to push more air into the engine (granted not as high RPM's because it's a pushrod). It's more effecient to put two midsized turbos on a larger engine, unless you can get a good midsized VATN turbo. Most builders don't care or don't know about VATN. Most race car engine builders don't care because it's going to be run at WOT the entire time, anyway. VATN is great for a daily driver, and the occasional jaunt to the track. But, they are a little more expensive, and you'd be hard pressed to find one on eBay. :p

peak power and power under the curve and curve shape are dramatically different.

CV6MTX, you seem to be hung up on peak power, which is fine for a car that will spend its life on the drag strip. Power under the curve, and curve shape are far more important to a street or road course driven car. Also, for a single turbo to make good power, the efficiency must be max at near redline for the large peak power. but on a twin turbo, the efficiency peak can be brought down a bit for better use of the efficiency of the twins, and still be capable of the same peak power levels. Aftermarket people like single because it is typically easier to set up to make peak power. Not saying a single turbo is never good, far from it, but you imply that there is never a good reason for a twin turbo, and that is just plain ignorant, stubborn and blind. I re-iterate that it really depends on the application and hardware being considered more than any general rule between single and twin turbo's.

Forget it...it's not worth my time to continue...

(cough) PMS... (Ahem)

Hahaha, no kidding. I was about to say that.

John

Twin Sequential Turbos= Use two low tech turbos with different A/R's to reduce turbo lag: One works good down low, and the other one up top. Low tech is usually cheaper and "Twin Turbo" sounds really cool. ---See RX7, Supra, 300ZX.

Once you understand that, you might have a chance at seeing why a VATN turbo is better than twin low-tech turbos.

VATN Turbo= One turbo that acts like two. Vanes close down at low exhaust gas volume (low RPM's) to spool it up (like Porsche). Once the volume of the exhuast gases go up, the vanes open to allow the gases to flow by, still spinning the turbine.
---See Mercedes, Mopar, Audi, BMW

Corkey Bell has a neat book out. Sounds like someone needs a new "engine builder" and needs to realize there might be a better way of doing things.

Ding, ding, ding...

...and We have a winner...

BTW...your wonderful VATN turbo...you speak of it as if it's great, but how come all I keep hearing about them is they are very limited in power making ability, and they break very often. Also, have a short live even if taken care of...sounds wonderful

Oh well...I'll leave quietly. Cause i's worthless to continue. If you care I used to work for BMW, so my car knowledge is not short lived. My engine builder is a Ford Engineer I met. So, before you start saying things, think first please. That's all I ask.

Enjoy...good luck to everyone...I thought we were all people with the same hobbies, I guess not.

Oh if you care come visit me on the cougar board under the name PGTATX...

Hey Demon and Chris hightower...I guess my name fools you...Check fastcougar.com, and you may remember who I am...just check the special section

CV6MTX,

I have no doubt that you are knowledgable, my only problem is the blanket statement that twin turbos is never better than a single. Both setups have thier merits and the particular application, its intended use, and the hardware available should be considered, without blindly choosing one setup or the other.

fwiw, there are at least several present and past Ford engineers here, including at least one from SVT Engineering (formerly SVE) as well as several more from Ford's suppliers.