What is the point of the imrc's? What exactly do they serve to do? Is it like opening the secondaries on a carb, when they open up? and is there any way to manually control when they open? (say, if you want that extra punch when your on the strip....i heard theres a lever or something at the rear of the intake that controls them, rubberbands on them?)
Someone explain IMRCs to me
- Thread starter MrWilson
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67Continental
Dedicated LVC Member
there is no "extra punch" to having them open all the time, you will lose low end torque. There is a design reason why they only open at high rpm, and that is because that is where they will make more power. Don't forget, and engine is a system, and someone took a lot of time to design it to work as a system. It's not usually a "if this was on all the time we would have more power" situation. Sure there are compromises, but in this case, the compromise is closing them for low end torque.
Grifter
Well-Known LVC Member
you can have TOO MUCH airflow at low RPM, which kills torque. the velocity of the air drops due to the increase in volume. so ford put a plate on there, like you said. to act something like the secondaries on a 4bbl carb. they only open when the engine is at th point of needing more air, and drawing in air fast enough to keep up the volocity.
67Continental said:
my understanding of imrcs are that they will give you more power nomatter when they are open, the reason they arent open all the time is because it would hurt the motor if they were. Atleast, this is my understanding.
MonsterMark
Dedicated LVC Member
And you would be wrong.:shifty:MrWilson said:
MonsterMark
Dedicated LVC Member
Ask any guy that did a IMRC delete and they will tell you they have a dog off the line. You pick up a little bit on the top end simply because you have removed the plates inside the intake tract that cause some interference with the flow.
driller
Dedicated LVC Member
MonsterMark said:
Unless you have boost and/or 4.56 gears.
Grifter
Well-Known LVC Member
or a 3500 stall and gears..
the imrc's let you make the most power when they open at 3250 as set from the factory. we played around with opening them sooner/later on the dyno with Chris J. from SCT, and the stock setting made the most power.
the imrc's let you make the most power when they open at 3250 as set from the factory. we played around with opening them sooner/later on the dyno with Chris J. from SCT, and the stock setting made the most power.
chicken
SHEOOOOOOOOT
bascially your intake has 2 different runner lengths for low or high rpm all the imrc's do is determine what runner you use depending what you need the car to do
driller
Dedicated LVC Member
Grifter said:
That explains the little squigglies at 3250 on my dynochart!
Here I thought the factory setting was 3000 rpm and there was a delayed reaction going on.
Grifter
Well-Known LVC Member
yep.. the little turbulence created by the imrc's when they open.
Moes8
Dedicated LVC Member
driller said:That explains the little squigglies at 3250 on my dynochart!
Here I thought the factory setting was 3000 rpm and there was a delayed reaction going on.
holy bananas,Ford wasnt lying back in 1993 when they said the "new" 4.6 had a "flat" torque curve,i cant believe how that torque is almost linear across the rev range,cool stuff.
what is done to the motor in that dyno run(compared to stock)?
driller
Dedicated LVC Member
Stock motor with bolt-ons.