GST Motorsports

iTrader: (8)

The above before/after test pipe was with a tune, then added test pipe to the tuned car. Then, added boost pill and tuned for pill and test pipe.

I would imagine something like a milspec 100 cell would work well.

tephra

iTrader: (6)

still +15/+17 isn't bad from just the testpipe...

i still wanna see that boost/afr for that chart thou

GST Motorsports

iTrader: (8)

Yea it's pretty inline with what I have seen with the 8/9's at this level of power. At higher power/airflow its exponential.

LaXGSR

Thanks Bryan for showing what you've found! Like tephra, I'd like to see boost/afr...my main question would be: are the gains from being able to run more boost with the test pipe, or are the gains from better airflow with the test pipe? For example, say I'm running 24 psi before test pipe, then I add the test pipe and untuned it runs 25 psi. If I then tune it back down to run 24 psi again, will I still see gains with the test pipe? Thanks!

tephra

iTrader: (6)

Personally I think the gains come from less restriction in the exhaust WHICH INTERN allows more boost (with the same DC).

In your example, I think if you ran the same boost+afr (after the TP/HFC install) then the power/tq should be the same (within 5 i reckon)

nj1266

iTrader: (6)

I know it is cliche, but the engine is an air pump. The more airflow through it the more power you will make. Put differently, think of a garden hose that has three restiction in it, at the begining of the hose (stock intake), the middle of the hose (stock cams), and the end of the hose (stock exhaust/CAT). Open the water through the hose and the flow sucks. Remove the last restirction (exhaust/CAT) and the water flow improves. Remove the first restriction (stock intake) and the water flow is even better. Remove the middle restriction (stock cams) and the water flow is much much better.

Finally, add a little electric motor (bigger turbo) to pump more water through the hose and you have water coming out of the hose that will clean dirt off your drive way.

So yes, you will make more power with a full TBE with tp. Add an Injen intake while your at it and you will make even more power.

tephra

iTrader: (6)

but what if the first restriction is the biggest? then removing the middle or last restrictions shouldn't make a difference

GST Motorsports

iTrader: (8)

The 02 and the downpipe is not a restriction on the stock turbo.

tephra

iTrader: (6)

yeah - DB was saying that as well...

nj1266

iTrader: (6)

On a turbo car, the biggest restriction is the last one, ie, the stock exhaust. Turbo cars love to run w/o any exhaust restriction. Just a little side dump pipe from the turbo will do. That is all they need. We obviously cannot do that on the street. But go to a race track and see how there is practically no exhaust to speak of on a turboed race car. Trubo cars hate backpressure.

GST Motorsports

iTrader: (8)

Backpressure makes a big difference. More flow, less backpressure can allow more boost up top where before WGDC was 100% and/or knock came into play. Changes in AFR at pump gas level make less power differences than you would think.

EDIT:

Here is some data from the 8/9's:

https://www.evolutionm.net/forums/ev...-cell-cat.html

https://www.evolutionm.net/forums/ev...trate-cat.html

https://www.evolutionm.net/forums/ev...st-system.html

tephra

iTrader: (6)

nj - yeah I know, but parts what about parts WITHIN the exhaust

bryan - yeah so the TP allowed more boost (or better boost efficiency) which explains to gain in power.

nice data btw!

gunzo

iTrader: (2)

If you're referring to the flapper valve like those on the 8/9's .. get rid of it .

You can cap the boost to that similiar to before the TP .. you still end up with higher torque once you install the TP ..

I do not know how the O2 will react .. but I can tell you .. the downpipe is probably a waste of time and $$ ..

crcain

Is the Evo X turbo elbow and downpipe larger than previous Evos?

I would have though adding a test pipe would decrease back pressure, increase VE, and actually make it harder to hit a target boost because the motor is breathing more freely (less resistance to make the manifold pressure).

However, less back pressure means less force availablt to push open the internal gate as well and overwhelm the actuator. Hmmm.

LaXGSR

Bryan, I think THIS part is critical to what I was trying to understand...currently, my WGDC is not maxed out at 100%, but what you're saying is that having more flow (ie, with a test pipe) will allow me to run more boost without knock. That could also potentially allow me to run more timing up top right? My main concerns with running too high of a boost level have to do with turbo efficiencies - at some point, it's just spitting out hot air Anyone have a stock turbo compressor map?