Jump to content
Sign in to follow this  
Contour Man

IMRC or No IMRC

Recommended Posts

is it possible to eliminate this and put a different intake manifold on? I don't like how long it takes the runner to engage when i get on the gas in first or second gear. I can like feel the car stepping up in power at about 2,500rpms, then again at an 4500rpms. Its kinda strange but then again I'm not sure how the runner control is actually supposed to work.

Share this post


Link to post
Share on other sites

The 2.5 was designed to have IMRC to keep intake manifold gas velocity high at lower RPM, this improves cylinder filling and power at lower RPM. As the engine reves go up the intake gas build its own velocity to a high level and the IMPC opens. I'd advise that you leave the system in place and check its operation with hood up and watch the linkage as you build up revs to see the links open the secondries. If the car has high miles you may also want to consider removing the intake manifolds and carry out a full cleaning on the upper and lower manifolds as they can gumm up over the years. To remove this system will give a huge flat spot at lower revs and loss of overall power...It was designed this way for a reason . Many engines have IMRC with various types of runner control...

Share this post


Link to post
Share on other sites

Removing the UIM & LIM to clean them is the best way to resolve many issues. However you could try the seafoam treatment first. I'd do that first anyway since it give you a good start on cleaning. BTW the secondaries should be opening at 3500 rpm.

 

AF

Share this post


Link to post
Share on other sites

lol spridget

 

I like high revving engines, so to me the IMRC is really fun.  The perceived lack of torque is really just the lack of displacement.  The dead spot is just part of its charm!

 

I searched the world over to find the "best of both worlds" and came across a 3.0 Hybrid with Stage 2 heads/custom cams.  Bought it, love it, paid too much money for it.  But, it has almost no "lag" - just big torque then on to an almost turbo-like rush up to about 7,300.  So I'd recommend a hybrid with custom cams. I know a lot of people don't like hybrids but I love mine.  Let the hate mail begin.

Share this post


Link to post
Share on other sites

I've built and driven both setups. I'll prefer the non-IMRC 3L over the hybrid 3L. My '99 straight 3L makes 85% max torque at 1800 rpm. It gained 30 tq on the low end when I swapped from SVT cams to stock 3L cams. Lost 5 hp on the top end and lowered redline from 7500 to 7250. Power falls off at 6750, the extra room is just to prevent hitting rev limiter.

 

That little kick at 3500 in the hybrid setup was nice, but the car never felt as quick as the full 3L. And higher revs just means increased wear and shorter engine life.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×

Important Information

By using this site, you agree to our Terms of Use.