Contour Enthusiasts Group Archives Forums Modifications Duratec Performance Twin Turbo?

I want quad turbos!

Where can I find some turbos the size of a hamster so they'll fit?!

Hee hee!

In most instances, head work and hot cams are great for NA engines. A nice intake manifold is great too. However, some of these mods that are great for a NA engine, are negated when forced induction is applied.

-With hot cams, you can lose a lot of the boost the turbo worked so hard to produce.

-High flow intake won't help a whole lot with air being forced in it anyway.

If you want to build an engine for turbo, do everything with the turbo in mind. Trying to get a huge amount of power out of an engine built for a turbo, but NA, isn't going to be very impressive.

Another point I would like to hit home, is the kit we are producing will be made to work on STOCK engines with stock compression, and internals. This is the same thinking Vortech had with their supercharger kit. If the turbo kit only puts out around 250-270 on a stock Duratec safely, then sobeit. However, initial estimates point a little higher.

If someone wants to use this kit to make a monster engine, I am sure it will be able to be modified to put out some much higher boost (CFM/PSI).

This kit will be made for average Joe that has a few grand to spend on a performance upgrade. This would not include an engine teardown. It will be offered in the same spirit of the Vortech kit, just different parts and results.

I thought that would be a very bad thing with the kit you are developing? In fact haven't they (the top secret company :D) made it more difficult to play with the boost over and above what they recommend. I had read that other cars using this type of turbo had failures when trying to tweak the boost.

hmm, well, it seems both of you ethier didn't understad what I wrote, or chose to argue different points.

CV6MTX, your arguments for efficiency hinge on improperly sized units for the twin turbo setup. and as such your argument is entirely based on a particular application with particular hardware. My argument was that a twin turbo can have benefits but which one was better completely depended on the application, its intended use, and the particular hardware being considered.
I have never argued that a single is not a good choice in many many situations, just that more often than the 5-10% you guys seem to claim is the twin (or more) turbo setup optimal. Heck, I even stated that for my Contour I would go w/ a single.
I still don't understand how you can believe that a twin turbo must inherently run at a higher pressue to make the same airflow as a single turbo. This is preposterous. For a particular application, if you design both a single setup and a twin setup intended for the same peak hp, each of the smaller turbos should flow half (or slightly more) of the cfm designed for the larger single turbo and at the same pressure. Again, it comes down to choosing the right turbo, both the compressor trim and the A/R ratio for a given application for which one is more efficient, and if both setups aren't pretty close for compressor efficiency, you have sized them incorrectly.

As to the VATN turbo, the durability info you have is honestly almost irrelevent, because you have no idea the actual failure rate vs. the amount in service. Your experience, while definately worthwhile, doesn't mean much in that particular argument. Now, a warranty claims summary for VATN turbos and a close estimate of how many are in the field, that could be useful in determining how reliable they are.

As to easier and cheaper. Cheaper, yeah probably because the VATN turbos are a bit more expensive than a good T3, but easier? I dunno, because the VATNs I know about don't require external oiling or cooling. plumb the intake and exhaust, throw a boost reference line to it and it all good, no need even for a real wastegate. Packaging is much easier too because it doesn't require an oil drain, so it can sit lower if you want, and it has more flexibility as to what angle it is mounted at, heck they claim you can even mount them vertically.

Bigprobe,
wtf does a little extra heat matter from the hot side of the turbo? as long as you don't have things sensitive to heat unshielded or too close to the turbo extra heat is irrelevant, and it isn't even extra heat, its 2 smaller areas of roughly the same amount of heat in different spots, sometimes this even makes things more manageable than a single. ok wait I'm confused, then you jump right back into compressor efficiency???? sure a smaller fan is going to have to spin faster to get the same volume of air as a larger fan, but remember you now have TWO fans to make that larger amount, so the smaller fan only has to make HALF what the larger fan does (am I the only one that grasps this concept?)

as to the Boost threshold comments, I was merely correcting your improper use of the term lag, for the non-turbo savvy that may be listening. I was not implying a search on my part for a particular boost response.

As to added complexity in adding a second turbo, yes it is there, but it is not always as difficult as you make out (sure a sequential would be, even in intake plumbing alone!) In a V-type (or flat) engine, exhaust plumbing is often much simpler for a twin turbo than a single (crossover tubes and all that) and it is typically much easier to place the turbos closer to the exhaust ports than a single. Intake plumbing may be a bit harder to do for a twin, but, IMHO intake plumbing is much easier to fabricate than exhaust plumbing.

Sure a 2nd oil line and water line will be needed (for some turbos) but since you are already doing one, a second usually isn't that big of a deal, and in some cases you can even tee off the first line (if they are large enough)

2+2=4 You see i know my math
Pubic scool taut me aloot

V...N...T.
Gotta love those 2.2's...


(Soon to be owner of 87 Daytona Shelby)

If the setup is being installed on an engine with stock compression ratio, the turbos being operated in their efficient range is very important. As a turbo spins past it's efficiency the air charge gets hotter. And hot air charge mixed with high compression like we have is a recipe for disaster without anything to cool the air down alot( a very efficient aftercooler, Nitrous, ALKY, or race gas). Detonaton due to a hot air charge can very easily melt a forged piston. An intercooler system on a twin turbo would only lead to more complexity in the design (there's not alot of space in our engine compartments) and nitrous or alcohol injection aren't very viable on a daily driven car...
Just a thought.

In all honesty, I don't think I would really consider any sort of forced induction on an SVT without an intercooler. Water/alky injection works, but is no replacement for an IC, especially on a street car.

Properly sizing the turbo(s) for an application is absolutely critical (though I find it humorous that OEM's rarely get it right) to avoid running the turbo's in a highly inefficient region of the compressor map, and to also avoid too much restriction on the exhaust size, while still maintaining a deirable boost threshold. Correct choice of turbomachinery is just as important with one turbo as it is with 2 or more.

One think worth noting is that a bit of lag would be maybe a good thing with the FWD SVT. What I mean here is that I think that if you put on two turbos, or do something else to get crazy boost at low RPM, aka the 1.8T Audi, what you may end up with is a car that has a 13 second motor and pulls 14 second timeslips because it spends all of gears 1&2 blowing rubber and smoke. Also the tranny in the Contour is not up to handling lotsa torque.

I think that it would be good to get a maximum of say 200# of torque below 3500 RPMs and no more than say 250# altogether with the stock drivetrain + LSD.

I had an 86Turbo Z. I did a bleed off for the waste gate..what abad azz car. I wish I had one right now..I need to et my Capri finished and do something with it.