Ported 4G93 vs. RRM 4g94 IM

[GreenPsycho]

First I want to quantify and qualify this thread:

This could be a general ported 4g93 vs. 4g94 thread. Unless you want to go DIY or go through another member, RRM is the only one that sells ported 4g94 manifolds.

This is a comparision in price and performance for both. I am not trying to flame one company, just stating the facts followed by my observations.

RRM's 4G94

Fact:

I bought this manifold 6 months back and have put roughly a thousand miles on it, maybe a bit more. I do live in the midwest, so it is susceptible to heat/cold cycles. However, it has never been exposed to salt. The manifold came powdercoated, which is supposedly more durable than paint. There were some peeling issues.












Total Price: $350, not including the extra money I will have to spend to get it powder coated again


Ported 4G93

I bought this from engineerboy, who sourced the manifold, ported it, even gathered all the extra bits you need for install at my request (and a little extra cash, including cable mounting plate, extra hose and bolts)

I spent an hour or so cleaning it up, washing it down and prepping for paint. Painted it with hi temp engine paint and installed it. Take note, you will need the extra items listed in the other thread, although lowes or home depot will have it. Also, you will no longer be able to use either IM bracket (one underneath linking it to the block and the one connecting to the TB up top). Once again, no big deal, as lots of people are running this way with no problem.

Everything bolted right up. The vacuum lines were a bit confusing as some of the places are in a different position than the 4g94, but if you are careful, it won't be a problem.

What is also good, is the 4g93 is alot smaller than the 4g94, which frees up some space.

Design wise, the 4g93 has a huge plenum chamber and what appear to be more efficient runners (straight into the block instead of taking a S curve up to it as the 4g94)

Both IM's were gasket matched, and you can see the difference in the pics below. The 4g93 is simply a better designed and more free flowing IM

Thoughts and Conclusions

Going from RRMs 4g94 to the ported 4g93 is like going from stock to the ported 4g94. The gains are very nice, pulling hard from about 4000 till redline. No throttle lag and excellent, very quick response. It also makes the car sound a bit meaner, not ricey, just meaner, kinda like a v6 i guess.

If i had to guess, I would say 10hp on the butt dyno over RRM 4g94, all that for 100 bucks cheaper.

And because of this, along with the fact that the 4g93 schools the 4g94 design and performance wise, save yourself the 100 dollars and port a 4g93 yourself or hire a machine shop to do it for ya.


Pics of side by side below

[GreenPsycho]

beware of the pics, some are super hi res, like 400 x 1600 so you can see detail



pic of throttle body plate you will have to fab:

[HobieKopek]

It looks like lacquer on the RRM IM, but if they say it's powder coated I'll take their word for it. Perhaps it wasn't properly cleaned before coating/baking. Just sucks they wouldn't do anything for you. I can only assume all the sensors still fit and everything. So far the only different parts I've been able to find in the 4g93 that aren't swappable (for better or for worse) with the 4g94 are the cam position sensor, cam, and the internals. Go figgur. Of course that doesn't mean everything else fits, that's just what I've found so far that definitely doesn't fit.

[ROCK]

We will just replace it. Even after 6 months I wll repaint it or replace it. Noramlly 6 mos is too long but that looks like it was not cleaned well before paint. They are blasted but someone did not do a good job with the sand.

ROAD/RACE

[coal]

I have been to a few powder coat shops, most problems occur from the prep and cleaning of the part, the prep and cleaning is the powder coaters responsibility. RRM should take it back and make you a happy customer, or whatever that would take.

[Blacksheepdj]

Rob - good to hear you backing your products, as always.

GP - now I can't wait to start my next set of mods...

[GreenPsycho]

yeah, i'm calling up rob tomorrow and we'll figure something out

just to clarify, i KNOW RRM isn't responsible cause they send everything out to be powdercoated, but i agree, i think the problem is it wasn't cleaned well or at all before application, cause the powdercoat is just "floating above"


hobie, all sensors and everything fits right up. i'm not going to lie, there are a few quirks, such as needing the throttle cable plate fabbed, not being able to use the braces, and also i believe there are 2 instances where there are vacuum plates that hold vacuum lines that don't line up or you can only use 1 screw hole, which really isn't a big deal since they don't need to be secure anyway

blacksheep, what are you planning?

my plans are to hopefully steal vince's title. going to be going with rrm hacker kit and build it up from there on my own

[HobieKopek]

Originally Posted by ROCK

We will just replace it.ROAD/RACE

Score.

[Blacksheepdj]

Cleaned up and reopened.

Keep this thread on-topic or your post will be deleted.

[GreenPsycho]

Originally Posted by Blacksheepdj

Cleaned up and reopened.

Keep this thread on-topic or your post will be deleted.

bump fellas

[Kid Lancer 7]

and were would we get this 4g93? order it from the dealer?

[GreenPsycho]

nah, check with junkyards in your area or even one of those online junkyards

some people even got it off ebay

[HobieKopek]

There are so many junked/parted 97-2002 1.8l Mirages out there you should have a VERY easy time finding parts.

[lancermarin]

If I may weigh in on a few points here..

At Engineerboy's suggestion, I sourced my 4G93 IM from car-part.com. The whole process was fairly comprehensive, and there was no doubt in my mind that I was getting the IM from the correct year Mirage.

Second, GP, Hobie was referring to the 4G93 head, and not just the IM (I think) when discussing what doesn't swap perfectly. For the intent and scope of this mod, it's interesting but not really necessary information.

Finally, I don't know what the RRM ported IM "feels" like, so I can't speak to it. What I can say is that a ported '93 IM makes a heck of a difference. There is a noticable increase in power, throttle response, and the sound.. my god, the sound. Like GP said, this mod makes this car sound mean.

My local Mitsu dealer recently opened its own dyno, and the sound of WORKS Evo's pulling to redline really gets me going. I've yet to see the price-point, though, and really have no idea how much a few pulls on a dyno typically cost. If I'm back in town (might take a few months) and the price is right, I just might go in for some base numbers.

I can't wait till the day I throw a turbo in this baby, '93 IM and all, and drive on in to that shop and see the surprised looks on all their faces.

[K.I]

the 93 def. sounds like a nice mod to have. the installation looks pretty complicated though