1300/1500 exhaust question

Jeremy128

Jeremy128

True Classic
I'll keep this brief after my long drawn out issues lately.
I got my hands on 2 free flow mufflers, and enough pipe to do the intire exhaust (all free). I am only using one of the mufflers. THe pipe is 1 7/8 diamter. Would this size pipe be OK for the 128? Too big? Just right?
As said, it was all free so I grabbed it. THe pipe is new, in a full 10 ft stick, with 2 more sections about 3 ft in length.The mufflers were installed, and ran for about an hour on another car.
 
I believe the original pipe size...

... is the metric equivilant of 1 3/4 inches in diameter... so 1 7/8 may be a bit big if you are trying for a perfect fit. The original downpipe just my fit INSIDE the new pipe and with a slot and some clamps, COULD easily "bolt in".

I BELIEVE the MAIN philosophy of exhaust piping is to continually be less restrictive relative to distance. Ever expanding, or growing larger. In other words, that pipe certainly won't restrict or strangle the system.

Additionally, the whole thing can't be proven GOOD or sound GOOD until you put it together and even then it will be mostly YOUR opinion in any case.

And that is what COUNTS. Do you like how it performs or how it sounds... if not, then, at least in this case, all it has cost you is time and some hardware.

BTW... some perforated exhaust tips can alter the sound of your car also... but they can get expensive, so choose carefully.

Have fun... send photos...
 
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1 7/8" will be good, and if it was for free then it's extra good.

I use 2" on 1300 128's ... and 2 1/4" on 1500 X19's .... so 1 7/8" is on the conservative side.

What will make the biggest difference to performance on a 128 sedan is getting hold of a coupe (euro spec) exhaust manifold ... there must have been a model of 128 / x19 / yugo that was available in the US that ran a dual outlet exhaust manifold? (apart from a 74X)

The sole (the one and only) difference between the 1971 euro 128 rally engine (67hp) and the 128 coupe 1300 engine (75hp) was the exhaust manifold and front pipe... 8hp going begging on any 1300 sohc just by changing from a single to a dual out manifold/front pipe setup.

THEN make a nice 1 7/8" system, perch the muffler under the rear seat, straight thru tail pipe, might be a bit of a drone at some speeds, but it will make a difference.

On 128's I always fit a small flex section after the gearbox support stay, then you can weld the whole system (no pipe clamps) and it lasts forever.

SteveC
 
I think I have the header you are referring to. It is a 2 peice set up. THe outlet ends meet near the bottom of the block, near the tranny.
I was planning on bolting them on, then running 2 seperate pipes until they go under the car. From there, was gonna use the flex pipe for abot 6-12" before goign to the collector for teh single pipe to the muffler.
Thaks for the info! Good stuff! I think this is the next project for the car. Hopefully I can get it taken care of in teh beginning of august.
 
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