It is the wastegate side hole in the flange design causing hella turbulance and thus increasing backpressure, in turn causing boost creep. Shearer Flange anyone? Or I guess you could take the dump off and port the inlet to the dump tube a bit to mimic the Shearer and that may help...

Also if you look at the MAP, the quality is good, however it has a serious design flaw... they have a stepdown on the dumptube as well, so that creates 2 separate points to create turbulance (the flange opening, and the stepdown) all within a 2 inch length of pipe.

 

Pin pointed the issue correct freddie,My exact thoughts but with a built motor and I wouldn't worry about the creep much car must pull like a bastard.

 

So my 3" version will be affected as well then.
I feel bad for EPM. These folks gave them a hard time on here about their dump but I never saw any posts about boost creep issues with it. I see EPM offers a full 3" integrated dump/downpipe now as well that eliminates the 2.5" donut gasket. Anyone tested it yet?

 

Yes it will drop..As far as epms new design I hope they add a flex pipe for it cause If it was on my car or freddies car it will crack in half within a week..

 

After seeing the 3rd spelling mistake on EPMs website I closed the window... If they can't even use spell check on there website, what does that tell you about the quality control of the parts they fabricate???

 

No, there is no flex pipe.

 

Rotfl

 

So boost creep isnt what I normally like, but for honda like powerbands it works good. Also on pumpgas if you can make it do it, you can cheat and make small cams work like big cams at the expense of torque. This is a built motor but this approach would work good on a stock block as well. I am not sure about this dump. Its the first time I have used this dump, the other MAP dumps have been the full downpipe version. The QTP, EPM, and R/T Ernie dont seem to have any creep issues on any of the Black equipped cars, nor does the full downpipe version from MAP. I would presume we are against some combination difficulties that lead to the creep like this.

 

I'm confused. I know of only one MAP dump. Are there different kinds?

-Acree

 

I didnt realize it was a built motor. Duh!

 

Thomas. nice numbers. good to see the car back up and running. you going to make the two day event at woodburn?

Fast_Freddie: strange. I have this exact unit, granted, im using a ported stock turbo and not a big one like the black, but i see no boost creep at all. I also gained near 70 wtq with adding this.

Thomas. is your black ported also?

 

I like rising boost curve. but initial hit needs to be higher. 300tq is really week for black. it doesnt make 450 till 7000rpm. I bet the car feels like it has a 42r on it. nice fwd powerband though.

 

I am going on the Hood river crusie this weekend. I think its ported not sure, I am trying to find a 3in 02 dump now

 

The black flows way more air than a stocker as well, the back pressure that the black will create at full boost versus the ported stocker is substaintial, hence causing the creep.

So let me rephrase my previous statement, on stock turbo with bolt ons, I am sure that the MAP O2 dump would be great, however when you are dealing with an upgraded stock frame turbo and increased turbine back pressure, the MAP O2 dump is prone to boost creep issues, as its design tends to increse the back pressure even more.

 

no need to rephrase on my account. Im sure ill get my own real data when i go red with map 02 dump. I hope the Map unit will move enough air. I think an easy "fix" would be to angle port the dump flange as in the pic you posted b4. Good times in partyville.