REW UIM Modifications...What can be done .
 

Hey guy's, what modifications can I do to my UIM to make it better for high HP. Its presently off the car and is untouched except for the removal secondary butterfly valves. What have you guys with high HP motors done with you UIM? My FD is presently running a litte over 500rwhp.

I didn't have that much power, but I spent some time on the FD UIM.

I cut out the 2ndary butterflies shaft's support and completely polished the interior surfaces.

I was able to polish and enlarge the runners by putting a 10" split mandrel on a die grinder and putting 80 grit table sander paper in as a flapper.

Place one end of the UIM in a bucket of water and access the runners through the other end of the UIM and you can fairly quickly remove a lot of material.

Then you can follow up with progressively finer grits to a polish.

I was adapting to an S5 FC LIM so I hogged out the primary runners to match the FC primaries on the UIM (and FC LIM 2ndaries to match the FD UIM 2ndaries on the LIM).

I don't know what your throttle body plans are, but I used a modified stock FD throttle body. I just polished/contoured the aluminum, half shafted the primary and put in flat head screws on both shafts, contoured the 2ndary shaft as well as knife edging the opening edge on the throttle blades. Used a bunch of lock-tite and never had a problem the last 15 years.

Is there any advantage to removing the center divider section where the secondary butterflys were?

You could do all that. Or use an RE upper manifold. MUCH better starting point.

I don't think so, I think that just adds turbulence, although I don't think it would be noticeable or even measurable.

When i removed my double throttle i removed the butterfly and the whole shaft.
I plugged the hole with a threaded pipe plug, not the usual block off plate.

I had my UIM/LIM extrude honed, then coated (teflon on the interior, ceramic on the exterior). I'm assuming you've already ported the TB and replaced the butterflies in that?

(I'm not running "High HP" but it's def something you could consider doing if it's out..)

i second the recommendation for upgrading to an aftermarket UIM.

Who's making that recommendation?

Aside from that, what aftermarket UIM did you have in mind?

I second this. Didn't know there were any UIM aftermarket options.

Closest would be JDM (RE or REW)

Every time I look at the stock REW UIM, I can't help but think it has to be a restriction. There is info here and there about the quad rotor racing engine and optimum runner lengths at different RPMs. But that was a p port. And the runners we're much larger in diameter. But what I haven't found is any info on manifolds for side port engines like the REW. I can't imagine that there hasn't been anyone that have developed a proven design.

Is Pro-Jay the only company making a UIM right now?

We've been working on one but still in very early stages of development..

I want one. Especially if it maintains the factory style primary /secondary divide.

Will you be making a semi-pp lower too? How for off the launch are you ?

Not mine but......nuff said :)
Looks decent to me....sort of RE but kind of improved

It probably wouldn't.. Currently looking at common plenum and provisions for bolting on DBW throttle body.

It's currently in design study stage so going to be a long ways off still. Lots of development and validating to go...

^That's what I like to hear. Release the product to the market once it's 100% sorted to ensure you have a winner :bubrub:

Any update on this?

For PFC ECUs.
Most really modded REW engines using a PFC end up with a non functioning ISC system.
But that allows setting all three idle speeds to 0 rpm and doing that will cause the PFC to actually use the IGL/IGT timing in the two timing maps for the idle area. This not only allows for more timing but also the use of negative lag which helps for a more efficient idle running leaner.

Since the ISC solenoid is not being used, remove it and fill in the large square opening in the UIM, and fill in the large oval opening in the TB. This is what I for my engine. Since I use the AC, I place a new aftermarket solenoid in the system to supply more air when the AC runs.
It supplies air through the old large PCV port.

All ECUS.
If you remove the hot wax rod unit, the TB can be modified to be symmetrical which reduces turbulence along with grinding on other parts of the opening. You can also remove the protruding 6 screws that hold the throttle plates in place, counter sink the holes and epoxy counter sunk screws there. All to reduce turbulence. Weber carbs are so much advanced in this area than what Mazda did. They think boost was the answer to all.

Then you can fix the TB that the high speed port plates open 100%.

@cewrx71r: do you have any more infos or pics about the mods you spoke about? I'm actually porting my tb and would like to do these mods as well, if they have any positive effect.

I'm abit curious about the ISC... some people delete it, but i thought i read some about it that it would necessary when using a Adaptronic to find stable idle... (changing from pfc to the modular this winter), and don't want to run into any issues...

One must think outside the box.
Take off your TB and learn how it works.

Ian, did you ever do a Turbo II TB? Wanna do mine for some extra pocket change? :P

I haven't done a TII TB, just went straight to the FD TB/UIM for that extra 30hp.

I am too lazy to work on my own cars, so doing work for others is right out.

But if you want an excuse for why your project isn't done yet, send your parts over to me and I will guarantee to not get them back to you:lol: