Hi everyone i am new..........
ok, I have the Divorce downpipe with a 44mm tial wasted gate vent to air on my evo x, I just installed a HKS GT2 turbo , and toke the internal waste gate out and let the internal flapper hang freely, recently i ran the car with HKS F-CON V-PRO, the turner said i have a huge turbo lag , because i am running a screaming pipe （Divorced downpipe vent to air) , is it true or I just have to fine another tuner?

 

depends if you have everything installed and plumbed correctly:

1. What exact downpipe are you running?
2. Are you sure you have no leaks in the exhaust housing (complete seperation between ports)?
3. Are you sure you have the tial and your boost controller plumbed correctly?

If everything is installed and working as intended I would not think you would have any additional lag over the internal gate... but you could easily have something setup wrong... for example if you were to reuse the stock hotside to 02 housing gasket you will have a very hard time spooling the turbo because you will not have true separation between exhaust gas paths. If the boost control system is not plumbed correctly you may be opening the gate way too soon.. etc etc

 

If you have the ATP divorce downpipe. You will lose about 500 rpm in spool. I know cause I ran that same setup for 10k+ miles on a 3076R.

You run no gasket with the ATP downpipe to the hotside. It will leak after awhile, due to the design of the downpipe.

Also I would of just tuned the stock ECU instead of wasting money on the F-con.

 

I ran it on my GT3076r without the gasket and indeed over time the ATP O2 DP does leak between the two chambers. Worst my spool got was 20 psi by 3700 in 4th, when freshly assembled it was 3500-3600 rpms. Not sure about a 500 rpm loss as my internal wastegate setup never spooled faster than 3500 either. YMMV

 

dont you have to weld the flapper shut when you go from internal to external gate

 

1.ATP 3" DOWN PIPE
2.no leak,
3.yes SURE

REPLY FROM ATP:

Charles,

Your tuner is right, you flow more but add lag if you run in external
wastegate mode on the bigger turbo.

 

YES I think might be the stock hotside to 02 housing

 

yes, if you weld the external gate on the exhaust manifold
no, if you use the ATP Pipe,cause gate is on the pipe where the flapper exit (the best way is take the flapper out)
i don't know how yet, cut?

 

500rpm seems drastic imo. Never really looked into fiddling with making an interally gated turbo into an externally.

 

i am positive its the flapper..... you have to either weld it or leave it close with the old internal wastage

 

yes , if ur gate is on the exhaust manifold
in my case, i have the gate on the 02 pipe bro........
u have to let the flapper keep open , cause the gate is right after the flapper

 

look of a user on evoxforums named hotdog. he used this dp with an fp green. His lag was hilarious. The DP is a piece of crap that adds major lag in exchange for minor power increase. IMO at least :-)

 

Not sure I'm reading you correctly... as others have said you should NOT use a gasket between the hotside and downpipe with the ATP... if you are using a stock gasket especially (which is NOT divided) you are essentially hanging the gate open all the time and slowing down the spool.

 

YES, You are 100% right, it is the sotck gasket, i didn't think when i intsall it,
i was just thinking of the the air leak if i dont use it.
toke that out, and no more hug lag, but still a little lag then before.....

 

Progress is progress, I imagine it has to spook a lot faster now than t did with the stock open gasket in there