[sutyak]

I have a spare intake manifold now for my D20 and am considering removing the IMRC valves and want to hear from those who have done it and if it's worth it.
I figure it's something cheap/free and I have the SCT PRP so I can tune to adjust for it.
However, if it does help with performance I'll leave it alone.
My car is turbocharged with 10psi.
I just assume those flaps get in the way when in boost.

I searched already and just found a few threads with no answers that trailed off into nothing.

If nobody who has done this steps forward then I guess I'll do it.

 

[afraziaaaa]

Guinea pig time....

 

[sutyak]

Guinea pig time....

Well I'll take a look at it and see what all is involved and see just how restrictive the flaps are.
I don't have the IM removed at the moment, but I will this weekend for sure.

 

[07FocusST]

I am not too sure about these, but the 2.0D has one Vacuum solenoid which I assume controls the flap(s) for all 4 cylinders. My 2.3LD has 2 Vacuum Solenoids which I am not sure what the second one is for. Deleting these flaps will only make your engine suffer in the lower RPMs as it is designed to help down low then open at higher RPMs to allow more air flow. Something to do with torque... I remember that my old 1995 Probe GT had them and you could tell when the flaps opened.

Since we are both using FI, I can't see how you would lose any torque/HP in the lower RPM range. Especially since we have the same turbo. My turbo thinks its a roots blower and has ZERO lag. Instant boost from the get go. Although I run out of breathe by 5K RPM's. I say give it a try. Let me know how it works out.

 

[sutyak]

Well I have 2 now and you can't give the things away (haha) so I might hack one up.
I'll let everyone know what I decide...

 

[NemesisEnforcer]

sporadic, there is a long thread about the tumble flap delete, where tb1999 and honhon got into it...i think there was a lot of info there...but it makes the car run poorly in cold weather.

 

[focusboy5]

I didn't think the 2.0 had tumble flaps.

 

[honhon]

it does, i found that out when i tore down my 2.0 motor.


and IIRC, tom can tune the car to run without them.

 

[NemesisEnforcer]

that issue came up in that thread...just search the title for tumble flaps

 

[sutyak]

Thanks for the comments everyone.
I searched title for tumble flap delete, tumble flap, and then just tumble and only 3 threads came up.
I'll just PM tb1999.

 

[warneej]

The 2.3L has the dual plane or intake manifold runner control that the 2.0L lacks. Both have tumble flaps.

 

[focusboy5]

Ok that makes more sense now. What exactly do the tumble flaps do?

 

[dirtbrown]

i know they are dif....but my IMRC has been broke for about a year with the code p1518 and my SVT runs great...im debating tearing apart the dsi motor apart and trying to clean it or buying a new one

 

[EricR]

Be sure to do a before & after dyno so you'll know for sure the benefit (or lack thereof).

 

[sutyak]

Be sure to do a before & after dyno so you'll know for sure the benefit (or lack thereof).

Sure, if everyone chips in for my dyno fees.
Just kidding. I doubt I'll get the opportunity to do that.
I also doubt I'll get the chance to do this delete immediately too.
It will probably be a Fall thing if I do it.

 

[tb1999]

Ok that makes more sense now. What exactly do the tumble flaps do?

Tumble flaps just improve the swirling effect at lower RPM.

As the air flows past the flap it tumbles into the cylinder helping improve the combustion process. Its mainly an emissions related feature.

I have not done a before and after dyno test or calculated the airflow restrictions or any of that, I just know that there is no benefit to retaining an obstruction in the runner if you are not worried about emissions compliance.

It does require a cal update to ensure the engine will run and idle properly without the parts, but the differences will be minor either way, once warmed up it's not going to matter much.

The manifold volume changer flap on the 2004 models with the second vaccum control is a torque management device and allows for 2 paths through the manifold, the longer path increases the manifold volume and improves cylinder filling at low RPM to improve torque, then switches over to the shorter path at higher RPM for less restrictions and amproved breathing etc.

Simple concept applied to many low displacement higher revving engines on different brand vehicles.

The surge felt is more to do with the timing changes as there are 2 different timing tables for when the tumble flaps are open/closed. When I deleted my flaps and adjusted my cal, I equalized my timing tables and the surge was gone.

The torque curve was more progressive than stepped, check out my dyno post. There is usually a bump around 3500 when the factory tumble flap spark timing logic is still active.

 

[06Roush]

i know they are dif....but my IMRC has been broke for about a year with the code p1518 and my SVT runs great...im debating tearing apart the dsi motor apart and trying to clean it or buying a new one

u might look into one off of a cougar/contour. i think they may be very close to the same part.