Contour Enthusiasts Group Archives Forums Modifications Duratec Performance The harsh truth about secondary removal

Well I just had her dyno'd.
Good!:
I gained 2 to 4 hp's up top @6200 rpm's or so.

Bad:
I lost almost 20hp and a crap-load of tq down low and didn't gain anything until 5800+ rpm's.

I am not very pleased (for obvious reasons) with these results. I didn't remove my rods, just the butterflies themselvs, so this may cause more problems than taking the whole thing out. I am considering pulling the LIM again and replacing them.
Does anyone else have any dyno numbers that contradict this finding? I hope so. I would also like to see numbers with the rods gone. I may better be able to deside what to do, at that point.

Thanks for the information. Now why don't you pull the rods and dyno? It's not like you can't put them back...

And BTW... 2-4hp from just removing those skinny little butterflies is impressive... I'm surprised you gained any power at all. If you remove the rods, which are much more restrictive, you will probably gain a lot more power.

Before you removed the butterflies did you ever wonder why they were there???

Yeah I did? I also wondered why the stock MAF had a septum that cut air flow by 35% and why the stock airbox was so restrictive. You are right, though. That is why I did not remove the rods. Looking at them, I don't see a way to remove the rods w/o cutting them out. It looks a bit difficult. Again, I wanted a "reversable" mod just in case the results were less than satisfactory. Glad that I did it this way.

The truth is, now I have to figure out a way to ensure that my IMRC actually does open my butterflies consistantly and reliably. I don't have a warm and fuzzy on that, right now.

My experience with the pinned secondaries is negative.

Listen to Terry ! Those parts are not just tonsils or appendicitises that you can simply remove without serious consequences.

BTW why bother with all these mods for infinitesimal increments in HP and torque (and regret it later)? I would instead buy a more powerful car !

My SVT already gives me much more than is allowed on our streets and highways. I really don't care if I got an additional (and probably virtual) 2HP.

Captain Bart, while I appreciate your input and respect Terry as much as you seem to, I think that you are missing the point. To be a Gear-Head or True Enthusiast you are constantly looking for ways to hop up your ride. If you get 3 more HP to the wheels, good going! Three more than you had. I agree that the gains that I see on the dyno don't warrant the loss that I experience... That is not a healty trade off. Some trade-offs are worth it. i.e. Lowering Springs... They (Eibach's) make your car ****ty on bumpy roads and don't even bother trying to navigate a parking lot with speed-bumps, but they increase the car's road handling 10 fold!
If I wanted to buy a WRX and start with 30 more HP then I would have! It is all a big challange. This IS why the CEG site is here!

I agree!!!!

Pro-Jay, Cut the Rods out and clean the out ports. I did it on mine and I like the results. You do loose some power down low but it helps up high. I have the SAFC to tune things in and I think it really helps things equal out. Yeah I wondered why the MAF is cutting air flow down...and why there is a nice bottle neck at out TB and why we have such a nice 180 bend in our exhuast too ..

Anyone got any dyno plots proving (significant) gain with the rods removed? I want to do it, but it is not reversible, so I want to be sure. I don't want to break the Intake open any more than necessary either. Stazi, you did this, right? Have you dyno'd?? Anyone else???