nuc

Car is an '84 Euro which currently has MSDS headers with an H pipe, no cats going into an OE muffler. I already have an Ott x-pipe, high flow cats and the original manifolds sitting in a corner of the garage.

1st option. Leave system alone
2nd option. Put Ott x-pipe on with the headers

3rd. Put Ott x-pipe on with the stock exhaust manifolds

I also have high flow cats to go with whatever system I install, if they won't hurt power I'll probably put them on to do my environmental part.

Fitment won't be an issue as my exhaust guy can fab whatever I
need.

Thanks for your thoughts

'84 euro 5 Spd.

SMTCapeCod

Are the ott pipes custom fit to headers now? I think 928MS was making a header x.

I prefer X, some prefer H. At these power levels, once there is some crossover to balance the pressure pulses, there may be some measurable difference but I think it is more a matter of preference in the tone than any seat of the pants difference.

However, unless you feel like the bottom end torque is too soft I would keep the headers, pick up a: http://www.summitracing.com/parts/SUM-643125/ (aluminum, but in Fla that's fine) or have your custom guy reproduce it, and keep the rest stock. The OE muffler is a restriction, and heavy, but being at the end of the system has less effect than the upstream components and absent a big uptick in engine output...I wouldn't axe it unless you just want to be really loud. Unless you add back the cats. And it would still be real loud.

The cats, being right up front..even high flow cats are likely to cause some erosion of HP. Whether its detectable again is another story. I think street cars should retain cats, but if there's no legal requirement its a personal decision.

So improved performance: I don't think you'll feel much from any option, except retaining the headers that are already on there....and being cognizant that a wide open system that gives you a little more up top may give a little less torque at lower rpms, which is no fun on the road.

BTW, nice color!

tilac999

What's the difference in sound between an X and an H?

Landseer

Option 4

Jetison the MSDS headers. Substitute 85/6 manifolds (more room / ability to remove bell housing cover for clutch and crank sensor access).

Then, you could have your exhaust guy modify your X to match the new manifolds.



(Once I got those MSDS off our Euro 84 they went straight to the dump.)

SMTCapeCod

Lore has it that the "H" is more of a lope. Which in my mind means that it isn't working quite as well.

James Bailey

The H has a more typical V-8 with dual exhaust sound where you hear the uneven firing order of each bank. With the X or a Y the pulses from each bank merge and you get a more Ferrari like "even" higher RPM smoother sound. Most think it SOUNDS more like a sportscar and less like an old Chevy truck with rusty mufflers. I would run the headers with a Y and a single rear Borla.......and actually that IS what I run

Ducman82

I agree with James. Im running a set of ceramic coated MSDS headers to a 2.5 inch Y, thru a race cat, then down and out a Flowmaster 40 series. Sounds great! got a grumble and rumble but has that nice sports car sound at speed. i plane to replace all the pipes with Stainless now that i have my TIG set up. just need to find pipe parts... :-)

tilac999

Does anyone know if the stock front euro muffler has an H crossover built into it?

nuc

Not counting the sound difference, would there be an increase in power if I did what landseer suggested re: using 85-86 manifolds with the x- pipe?

Thanks for the feedback so far!

Lizard928

MSDS headers,
X pipe mating them together,
dual 2.5" all the way back,
straight through muffler (or two).

James Bailey

The headers work better overall plus they are already installed just add an X or Y single exhaust weighs less and only need one mufffler.

Lizard928

Jim,

In talking with Louie, the X and dual 2.5 will give slightly more mid range.
His question was what gives the most power.....

I personally would only do a single on my car.