James-man

X + RMB = A significant sonic presence.

No installation problems. Fairly easily actually.

I think that I will enjoy this. Not sure how tolerable it will be on 1+ hour drives. I will know after I drive to the track next weekend.

I have found I have to clutch-in for deceleration otherwise it gets a little loud while in civilization (neighborhood driving).

Can't wait to get it on the freeway and onto the track!

Yea baby!

the flyin' scotsman

James..............which X & RMB?

Did you notice much seat of the pants difference?

911Dave

Do you have cats or not?

James-man

Motorsport (Ketchmi) X.

I only drove it a couple of miles (mostly neighborhood + a little on 45 mph road). Haven't had the chance to really, really go yet. sigh.

I'll report back on performance after pounding the pavement.

James-man

No cats. It is amazing how much the stock cats muffle sound.

James-man

It has been rainy here lately, but the track was dry for most of the weekend.

Because my other tires were too worn, I had to use my nearly new street tires: Falken 451 Betas. These tires performed better than I had expected for a set of cheap streets. I was very impressed with them.

With RMB and without cats, the X pipe makes the car pretty loud but it was fine at cruising speeds on the highway drive down. The gas pedal is now the "loud" pedal.

By swapping the cats for the X-pipe, I have noticed that engine braking has been dramatically reduced. I haven't thought through why this would be, but when decelerating, it doesn't scrub as much speed off as it used to. Ultimately I find this to be a good thing. This and the sound are the two most noticable effects of the modification.

At the track, I found myself tapping the brakes instead of just lifting at the high speed kink due to higher speed. I already knew the lines at this track so I would attribute the higher speed to greater power rather than improved driver skill.

I have found that I am in need of honing heel toe skills so that my downshifts can be at higher RPMS to allow carrying more speed through turns (This weekend, I only tried heel-toeing once, but I was successfull! ). In otherwords, my downshifting has fairly consistently limited my exit speed in turns before the straights, so I think it is reasonable to conclude that my higher speed on straights has been due to an increase in power.

I would like to report statics for you but I don't have anyone recording lap times for me and when I was reaching my usual lift or brake points, I was watching the road instead of the speedometer. The few times that I did sneak a quick peek, I was doing over 5mph faster than at previously events (but less than 10, i think). I was gaining pretty quickly on a 3.6 turbo on the straights (on turns is more a reflection of relative skill, on straights is a reflection of...)

The next time I hit this track, I will increase my exit speed with heel-toe supported downshifting so any further data collection will be sketchy here.

Now I am just waiting for the weather to dry up for some subjective street bursts. I did sneak a quick one on the drive home from the track yesterday, and I think that I am feeling that the power band has smoothed out a bit. Before, the transition from low to medium RPMS had been a little abrupt during acceleration. A nice improvement.

The sound is awesome! I am guessing that I have around 15 HP more now than the 271-272 that I dynoed with RMB + Chips last spring. I would like to tune fuel pressure at the next dyno day. Any guesses?

I am expecting an increase in gas mileage. 1 hour drive to the track and 1.5 hours on the track = 9.3 mpg. Not bad?

drnick

i drove my 86 for a while with rmb and x, loved that sound... even when i eventualy took it to the shop for a custom exhaust i was reluctant to admit that i actualy did want it quieter!

James-man

The volume will help with gas mileage for street driving. Since I am one that does not want to draw attention, I will take it easy on the loud pedal and use less gasoline

I can put my rear muffler back on or I might put on some performance cats. Heck, I might even try putting in some "turbo sound" gadgets with the hope that it would muffle things a hair.

The sound is actually very tolerable for around town driving if I don't put my foot into it, so I just might keep it the way it is. I would bet that Porken could come up with an invention for me.

drnick

funny, thats exactly what i said after the x install about improved gas mileage with the lighter r) foot!

DoubleNutz

No CATS, with a RMB in a 86.5????!!! That is incredibly loud!

James-man

Yes, but it depends on how you adjust the loud pedal!

I got zero comments on it at the track and I had it turned up to 11. I only got comments on how fast I was. Somehow, there are louder cars with less displacement at the track - maybe they have megaphones or something? Maybe mid and rear engine free exhaust systems having only a couple of feet of pipes makes for more sound?

928drvr86.5

Not at all. I think i heard someplace that the 85-86.5 32v'ers have larger resonators than the S4's. At any rate i have been "testing" with my testpipe and RMB for two years and IMHO it is not overbearing UNTIL you start hammering the gas pedal. Even at WOT the sound is loud but musical. The car always gets comments like, "that thing sounds awesome" while at stoplights.

James-man

Agreed. We know that GTs have smaller resonators, but I wonder about S4s.

The catless X installation is not as loud as I had feared that it might be. The other unusual thing with 86.5 is I have compared the sound of my car WITH RMB against 85 and 86 cars with stock exhaust and their idle exhaust sound and note is much more impressive. Our big resonators must be muffling sound more than earlier and later 32 valvers. They just gotta be. There isn't any marked difference in the catalytic converters between these years are there?

I would have a hard time believing that I had plugged cats (that could mute sound) 'cause I got good dyno numbers with them in place. I think that there is more to the 86.5 MY than just the brakes!

MANY THANKS TO DAVE LOMAS @ MOTORSPORT!!!

Peace, y'all!

atb

All of the S4's went to the smaller resonators somewhere in the '88MY. My '88S4 A/T came with them. The big resonators came back with the GTS line.

hinchcliffe

So has anybody put the Test Pipes against the X-pipe in dyno and sound tests? I have an '87 with Test pipes, stock resonators and RMB so mine is as loud as the '85-'86