I'm currently undergoing a twin turbo kit on my xf... nothing over the top.. just enough to make it a fun driving car

im just wondering if anyone has found out what the stock MAF flow limit is?
just how strong are the factory internals?

again, setup so far is twin ct12a's w/ a ceramic turbine wheel
depending on what i can get away with timing wise probably no more then 8-10psi which should net a healthy 300crank or so

i'll be making the headers, downpipes, exhaust, intercooler piping and such myself, so no problem there

and if i cant get away with a simple AFC hack then i'll probably just toss a haltech on it

 

All fine and good, your internals will handle that boost. But, how are you manipulating the ECU/PCM to run the engine ? Therein lays your problem...

 

I think your on the wrong forum if your looking for information about how to tune the crossfire under boost.

this is not the place to ask these questions because no one here knows how to do it, it;s not thier business.

try a turbo or supercharger tuning forum for more in depth answers to your questions.

 

I would love to see you succeed. I have yet to see anyone succesfully tune a turbo crossfire.
My advice is not to give up but reaserch and have a plan before you start buying and plumbing.
Many have done the mechanical part but it falls apart when dealing with tuneing the MB computer.
Best of luck. Let us know what you learn if you don't mind

 

i know how to tune turbo cars... i build drift cars and i race, lol
im just trying to figure out the limits of a stock block..

more than likely i'll end up going full standalone so i can ditch the MAF... i hate them with a passion
they are restrictive and are a **** poor way to run any car
a haltech will fit my needs just fine

the only restraint is room
its not like theres a canyon in the xf engine bay

so im ditching the stock rad fan and going with two 12" pusher fans between the ac condensor and the radiator

turbos will sit in front of the motor, downpipes will go under the font of the motor, i'll accomplish this by using oval tubing so i dont give up ground clearance and it will be nothign more than dual straight pipes out of the back

the intercoolers im using are 2 mr2 upgrade intercooler cores, the sizes and endtanks are perfect to fit behind the front grille, provdieed i remove that little airbox dealy

and then from there i'll basically run two intercooler pipes into one right before the tb

i may very well build a custom intake mani that puts the trhottle body in front of the motor, just to make plumbing easier

but i figure 555cc injectors, a walbro pump and an aermotive regulator will be fine for my power levels

 

Well, since you seem to have it handled with the electronics, i'd love to see your progress... I should be racing my Crossfire at Road Atlanta on August 9-10 and would love to see this while I'm in town. Let me know...

I'm not sure what you are referring to with the "limits of the block"... If you elaborate I can probably enlighten you...

 

You're going to have to be running some very, very small turbos to have them in front of the motor. T25 at the most.

Are you sure you've really thought this out?

 

Yes I have. Twin turbo setups don't need huge turbos t make streetable power

Each cylinder bank is roughly 1.6 liters. With two t28s I could easily make 500whp. Hell my sr20det made 300whp @ 14psi with one t28.

The ct12a's are roughly the same physical size as a t25. And each flows 25lb/min efficiently around 10-12psi so assuming the motor has 100% volumetric efficiency (which it doesn't. In theory) I should make 500 crank horsepower. But there are limits with pump gas as well as the strength of the internals.

It's not psi that matters but airflow. As there's only so much air you can shove into that clyinder before thngs start to break

 

Not in attempt to dissuade you from what you are doing, but I find it hard to believe that a single CT12A can flow 25 lb/min efficiently. In fact, I'm not sure where your numbers come from. In fact, they sound wrong. The CT12A should be rated at 100kW each . Two CT12A's are 200kW, which comes out to 272 hp. This is in agreement with the factory rating of the 1JZ-GTE that came on the old Supra/Soarers.

There is a huge difference in the compressor between a T25 and T28 turbo. The CT12A turbo is about the same as a T25, but it is not going to give you 25 lb/min! More accurately, the CT12A will give you a maximum of 100kW per turbo.

I would suggest dual T28's with 60 trim compressors. But even then you are going to have some serious space issues, especially if you have built-in wastegates.

Also, psi does matter, as well as airflow. The airflow the turbo can provide is not necessarily what the engine can use. A hypothetical turbo pumping out 100000cfm at 15psi stuck to a 3.2L M112 Mercedes Engine will not be able to use 1000000cfm. No. In fact, the turbo would actually experience something called 'surge'.

Basically, to make 500 crank horsepower, you're going to need a turbo that can run at a pressure of 21 psi, as well as flow around 550 lb/min of air. The engine determines the required flow rate required, not the turbo. CT12A - no way. T25 - no way. T28 - 60 trim could work.

 

I have the compressor maps for my turbos. Trust me. They will flow 30lb/min but that's at the end of the island and it's nothing but hot air
As far as the t28s. We've made 400whp and more consistently with vq35s.

And this is just a first round experiment. I have enough turbos and wastegates and such laying around that I'm fine.
I was originally going for a single setup but there just isn't enough room
k

 

A single CT12A making 30 lb/min? That's a laugh. If anyone else reads this thread: Avoid the CT12A turbocharger. It's a piece of crap junkyard turbo that boosts half as much as a T3 50 trim off a Saab 9000.

A single CT12A making 30 lb/min. Hah. So why did Toyota have to put two of them on a 2.5L engine?

There's still a fella up here in Minnesota who I said I'd give $20 if he finishes boosting an NA crossfire. I'll offer the same to you once I see the dyno sheet!

Could be the easiest $20 you ever made...$40 if you make 500 bhp using twin CT12A turbos. Prove me wrong!

 

Possibly a good place to look is on one of the Benz forums for the 3.2 liter. Someone on those forums might have an idea how strong the internals are and how much boost the engine can handle.

Keep us posted on what you find- I'm really hoping you can pull it off!

 

Another day, another twin turbo crossfire thread..

Good luck

 

i was saying that was at the edge of its efficenecy. the ceramic wheel comes apart long before you can reach pressure ratios to achieve that flow
they will pull 20-23lb/min within their shaftspeed limits

nowhere did i ever say i was going after 500hp... i was saying on paper in a perfect world, thats the combined airflow they could make.... but in the real world its significantly less, not to mention our motors wont take all the air they can be fed at one time.

i am simply aiming for 300whp. a nice conservative number that makes it a fun street car... as i am heavily involved in hosting and working drift events, this crossfire gets slid an awful lot... and trust me, the car needs a major kick in the *****

and i just got the turbos.... the guy said the were ct12s but they are actually steel wheeled ct20b's off of the us 2jz
w00t

 

Like I said, show me the dyno sheet, you get your twenty dollar bill.

 

lol, will do.
if i dont get fed up and sell this thing first
car payment i make should mean a faster car

 

if you read the shop manual, it clearly shows, two, 4 bolt mains, and two 6 bolt mains on the center of the crank support. sounds like it can handle 400hp easily.

 

you sound like you know enough to be dangerous...talk is cheap, let's see how well you walk son!

 

That in itself is a major feat with the intrusive TC... How did you disable it to drift / slide the car ?

 

I'm not knocking anyone cause hell, I don't have the knowledge of turbos. Just started learning about them off an '08 F350 6.4L with a VGT setup about three weeks ago.

But this sounds like an out before getting into it.


Justin