scalbert

This isn’t a problem but just something I was thinking about. Since the blower is in place, what is the need for the IMRC?? Would removing the IMRC plates provide any benefit or determent??

IMO, their removal would provide zero benefit. But I was just thinking and tossing out a bone…

AcurajL

Define IMRC.

scalbert

IMRC (Intake Manifold Runner Control), or rather it is the dual stage intake manifold but has nothing to do with the runners.

It is the control and components for the butterfly valve in the center of the plenum.

ModAddict

Perhaps it would still benifit throttle response at times when you're not in boost, and the blower is in bypass mode. Is the IMRC acctuated by vacuum or electrically. Rig up a manual acctuator control and do a little street comparing. These early installations are the pioneers for the rest of us. :thinking:

scalbert

Good point about the throttle response.

The IMRC actuator is controlled by the ECU and is completely electric.

Zapata

I would assume you'd loose mid-range and top end power. Especially, with the supercharger. It'd be a good dyno test. Especially since our engines aren't reving very high. If our engines were more like the ITR that rev'd MUCH MUCH higher then having the "modified" single runner would be ok because we'd gain back what we lost on the top end.

Jens H.

Scalbert .The IMRC (aka "I Must Race Car " valve) Is there to allow better power production at both high speed engine ops and low speed engine ops .Since the engine/blower makes no boost or very little boost at lower engine speeds it is still good to have it in place .Once the engine is operating at a high enough speed the IMRC opens the runners up for increased flow.So if anything eliminating it most likely will reduce bottom end performance and do nothing for top end.
Our recent blower install showed about 4.5 to near 5 psi on a real hard run through the gears .In speaking with Comptech they suggested that the blower is good for about 4.5 PSI.
I was told the same for my JAckson Racing Blower on my Miata .This kit was originally set up to produce about 5 PSI.However after a few years of twiddling I found that it can generate nearly 6.5 PSI.
I discovered that there are a number of places boost was lost in various items under the hood.I suspect there are a few spots where boost might be "leaking" without really having a vacuum leak per se.
Amongst other tricks my Miata has a number of one way valves that prevent boost from going into systems on that engine that need to see no boost.
Jackson Racing eventually added a few of their own tricks to the kit to correct some of the boost loss.I suspect that Comptech may also as things go on and we learn more about how this car reacts and interacts with this blower that a few "tricks" may be needed to fully realize the potential this blower has for this car.
I understand that you have a lower operating temp t-stat and a lower operating temp fan switch .Could you provide some details as to where these where obtained?
Thanks Jens

Zapata

scalbert

One thing that is often forgot or not realized is that we do not have variable length runners as with the ITR. Ours is a variable volume system, very different.

Plus, I know the Eaton blowers very well, I've even ported one. They, including this one makes nearly 100% of the boost (about 80% - 90%) at the lower revs. Even at 2500 revs I see about 90% of the peak boost.

So when on the throttle the plenum is pressurized. The resonance charge may be negated at this point. This is where I was going. When the plates open the Hemholtz effect may not take place when under boost. I dunno, just throwing out possibilities…

It would be an interesting test for the dyno though.

scalbert

I got the Mugen units from King Motorsports. I used the B series motor Fan Switch and the H series T-Stat:

Fan Switch Civic 1999-2000 [37760-XK5-00N0]
Thermostat Prelude 1992-2001 [19301-XGMR-0000]

http://www.king-motorsports.com/

ModAddict

If it is set at a specific rpm electronically, maybe it could be manipulated to a different rpm, or changed to be controled by vacuum, or the onset of boost.

Jens H.

Scalbert I sent you a PM about your boost questions .Hopefully this may get some answers to your rather low boost results.
Jens

Nashua_Night_Hawk

SCalbert, Dyno test is best answer for this question.

1) Strap your CLS on the Dyno
2) Run your CLS as usual (#1)
3) Disconnect the IMRC Cable
4) With the Butterfly Valve open, rerun the on dyno (#2)
5) With the Butterfly Valve closed, rerun the on dyno (#3)

Compare #1, #2 ,#3.. I think if you see significant boost below 3800 rpm dyno run #2 > dyno run #1.

Good luck.

DtEW

(I believe that what you mean is that the Integra GS-R had been equipped with variable length runners. The ITR did away with that in favor of a one set of runners for higher peak power.)

I am RobG

couldn't you somehow rig a v-afc or s-afc or something along those lines to control the IMRC? and wouldn't getting rid of it have an effect on the VTEC?

scalbert

Actually I was clueless on which had what, I went on the previous statements. But if the GSR did have variable length runners then it was the one to compare.

But it is irrelevant as we have a (not you) variable volume plenum and not variable length runners...

EricL

Excerpt:

"Forced Induction Issues

It can be seen that the resonance frequencies and torque peaks can be greatly affected simply by changing tube lengths and diameters. Similarly, changing the density of the incoming air also causes changes. The engine computer doesn't know how to set the butterfly valves to take advantage of non-atmospheric-pressure air, and so the primary and secondary resonances cannot be taken advantage of under boost. However, since the turbocharger or supercharger is doing the work of pressurizing the cylinders, you don't really need resonance charging anyway as long as boost is present.

Mazda's turbocharged 2L JF engine did away with the butterfly valves altogether. The manifold was designed to provide a primary resonance charge at 1800RPM and a secondary resonance charge at 6200RPM. The low RPM primary resonance was probably designed to help generate torque before the turbo spooled up.

The fact that turbos don't provide much boost at low RPM's means that the VRIS can still be useful while the turbo is trying to spool up. Even with centrifugal superchargers, boost can be pretty low at low RPM's so the VRIS can still be useful off of idle.

The big problem with the VRIS is at 6500 RPM +. The engine computer shuts the butterfly valves, severely restricting airflow. For atmospheric air, the secondary resonance pulses would help charge the cylinders, but with forced induction, the high density air being force through these passages will not be able to achieve the secondary resonance, and will lose a lot of pressure trying to squeeze through the restrictive passages. The only way to get around this problem is through some ECU reprogramming to keep all the butterfly valves open at high RPM's. "


http://www.geocities.com/mikey9t6/car_uvwxyz_vris.htm


There is some information that is irrelevant (RE: the 6500 RPM issue). However, once you are in positive pressure territory, you probably want to open up the flap/plate splitting the two chambers. At a minimum, the speed of sound (due to air density) has changed, and you really want the S/C to get as much air into the engine as possible.

There was another engine around that looked at engine speed AND manifold pressure to control the plenum operation, but I can’t find it…

IOW, you probably want to open the plate once your pressure goes positive...

YMMV

EricL

V-TEC doesn't care about the IRMC.

Just grabbing the intake pressure sensor output (already clamped/intercepted by the Comptech S/C kit) would work to provide a 2nd signal to the IRMC.

scalbert

That is an excellent point. A Hobbs switch in parallel to the IMRC controller. So that when under boost, regardless of RPM, the plates open.

But since a positive displacement blower is being used and boost is present with anything over about 30% throttle, maybe just removing the plates would be better.

This should be easy enough to test on the dyno which I will try to do.

typeR

i know this is stupid kinda ,but, though it would take a power dome hood it's almost like a roots type blower could take the place of the intake manifold cover...the pulley would be right there...wonder if it could replace the upper intake itself

scalbert

Actually, it could be made to replace the stock manifold and would have made it closer to a stock type of set up. But IMO, although the install wouldn't have been more difficult the power numbers would be unknown. The current manifold design is pretty nice so by removing half of it (more like two thirds) and replacing it with the blower could help but most likely kill, mid to low range part throttle performance.

This would have taken some serious R&D which might result in less power. The safer route was probably the better for Comptech. That doesn't mean that someone won't try it eventually...

typeR

SUPER RES

NOLACLS

SUPER MYTH...poof