Contour Enthusiasts Group Archives Forums Modifications Duratec Performance Twin Turbo?

if you ran a small turbo off each manifold(header) would it be worth it. it would be more efficent. i got all winter. i will have the motor out of the car anyway. I also need to find rather small and cheap turbo. any one know of some i can take from another car. i know i will have to do some custom fabing. that is no problem.

*hint* i hope a 3.0L can take a twin turbo.

the real problem for a TT in a 'tour is packaging it all.

drop me a line, and I would be glad to give you a hand designing a system.

Using a twin turbo setup is not more efficient than a single larger turbo. You need to run the 2 smaller turbos at a higher psi to make the same power than the larger single turbo, which will create much more heat, hence lower effieciency. Looking at the Supra TT, many owners switch to the single turbo kit, since they can produce over 1000hp easily, whereas the twin turbo upgrade kits are limited, and require even more work.

Twin turbo set-ups are never better. Many people say lag on a single larger turbo would be too much, but it's not. You'll be using twin 16g's, or a single T3, T3s60, or T3/t4 hybrid, and they don't have alot of lag. I know that the T3 S 60 reaches max boost around 3000RPM...even a tad lower, especially if you have airflow increasing mods, like P&P heads, intake manifolds, etc. 2 sounds cooler, but 1 is better, also trying to fit 2 in thsi car will be tough. Go find a nice T3, port it out to a t4, and you got yourself a hybrid..., and it's not that expensive.

Good luck either way. If you do a turbo on the 3.0L, use the 3.0L heads since it uses larger valves, and will have lower compression ratio than if you use the 2.5L heads. I believe if you dome the 3.0L pistons, you can lower compression even more, which will allow you to run even more boost.

Again, good luck, have fun...

I think you might want to wait and see what Chris's kit will do.

Correct me if I'm wrong, but the main reason to getting a TT setup was to get rid of turbo lag.

Once Chris's system comes out, I think you'll see that turbo lag really won't be a concern...

John

CV6MTX,

twin turbo is NEVER better? wow that is an awfully broad statement. It really all depends on the particular application and the efficiency maps of the turbo units being considered, and the desired performance from the setup.

You are right that "lag" from a single turbo is not always as bad as many believe that it would be, but the boost threshold is often higher on a single than a twin, making power delivery even less linear, and therefore, less street friendly.

I just think you have made far too broad of a statement for it to be valid; the particular application, and hardware considered is key to the characteristics of a system.

oh, one question, in a generic situation, why would a twin have to run a higher boost pressure to make the same power as a single? the power of an engine is only determined by the amount of air and fuel combusted (and how efficiently, but that isn't a concern here) minus the parasitic losses through the drivetrain, and since the turbos are driven through the latent heat and pressure in the exhaust flow, which would be wasted through the exhaust anyway, what makes a twin have to run at a higher psi? there is no reason excepting that the twins would have to be horribly undersized, and running in a system with far too many parasitic losses.

I'm really not trying to be argumentative I just love discussing this stuff

Once upon a time, Albert Mirko was working on a twin turbo setup for the Contour. Not sure if he ever got it working, but the price tag was along the lines of $15,000.

Boost has nothing to do with RPM. It is dependent on the volume of exhaust gases that are spinning the turbine, and how much air is getting sucked/pushed into the intake.

It depends on where you take the boost measurement and the comparitive sizes of the plumbing. One could run 35psi thru a straw, but what does that get you?

(Pulling out the equation book..)
Take for example:
(1) 4" diameter pipe can flow 2 x the amount of air that (2) 2" diameters can at a given pressure (staying in the laminar flow).

Therefore, in order for it move as much air as a larger turbo, the smaller one would have to develop more psi (move the air faster), unless as stated below.

But, (2) 3" pipes can flow about 12% more air than a single 4" pipe. In this case, the smaller turbos can run at a lower psi and make the same air as a larger turbo.

So, to answer the question. Yes and no. It depends on the geometry of the pipes as to how much psi the turbo needs to develop to achieve a certain amount of air flow.

This was the "simplistic approach." There are a lot of things that can change, as to the location of the psi measurement to the whether you want the engine to be "presurized" or have an ample supply of air. It all has to do with volume and air flow.

yes, a very broad statement...I wonder what porsche would think of that??

I agree with Rara totally.
Ben Timm, if you want to setup twin turbos I would suggest two Garret T-25's from a couple of 2nd Gen. DSM's. You'd be able to buy them for around $150 each from a couple of DSM'ers who have upgraded to 16G's or larger.
They would spool very quickly and provide you with enough boost to 7000rpm, seeing as one is rated for 5500rpm @ max cfm on a 2 litre.
I too would LOVE to help you design this system. I think Rara and I could come up with something crazy. The trickiest thing would be oil feed and return lines and the exhaust work.