Hi,

I have a 88 v6 fiero 5 speed (131000 km) with custom exhaust 2" with muffler without cat.
The muffler is placed instead of the cat and I don't like it.
This muffler bother me when I would work under the car the muffler is too big.

I want to place the muffler in the rear as the stock one.

The car car has :

-custom exhaust with deleted deleted cat and 3.5 resonated tips.
-Exhaust manifold has been ported (for the 6 holes with New gaskets) by me.
-New performance ignition coil and distributor and cap
-New 6 SPARK plug ngk iridium 9 with New 8 mm cables
-New kn air filter with kn oil and gas filter
-New castrol long life titanium edge engine oil 5w30
-New transmission 5w30 oil
-repaired exhaust leak and exhaust manifold leak
-proceed to clean the injectors with injector additive cleaner (ecotec 1101 and bardhal brand in Europe), I have an 6 accel New injector, I think maybe to change the 6 injectors i Will see after the second injector cleaner.
-New preventively changed sensors as oxygen temp filter, map, coolant temp ecm, soon New o2 sensor exhaust
-egr Block off exhaust and intake manifold
-New clutch kit and New clutch Master cylinder
-New brake Master cylinder.
-And some other works like New oil pan...


My question is I must stay with 2" pipe for New exhaust 304l stainless steel or may i use 2.25 or 2.5 with a New sport muffler (maybe akrapovic).. I don't need a cat because before 1993 in my country that's not mandotory to have it.

Thanks.

[This message has been edited by zobari (edited 11-12-2018).]

I do not think you "have" to stay with any size piping. Its really what is going to fit. This will all come down to who is doing the work for you. Reading what you have done with the car you really do not need the bigger exhaust. If you had some engine work this would be different. Now if you plan on doing something down the road to the motor this could be your time to plan ahead.

Dyno tests done years ago by Herb Adams, confirmed that the Fiero exhaust system with 2" pipes, for its 2.8L engine is very efficient. Herb was an engineer working for the Pontiac advanced development group and did the tests under very high tech conditions.

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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

[This message has been edited by Dennis LaGrua (edited 11-13-2018).]

If you want to reuse any part of the current system, like the muffler and tips, there are reducers available that will take you from one size pipe to another size pipe.

Unless you plan other modifications that will significantly increase your horsepower, you will likely see no gains by going to a larger diameter exhaust.

Ok many thanks.

The only other possible upgrade is if i can find a trueleo intake manifold.
I will keep the 2" pipe for the exhaust.

That would be a good choice and save you money in the long run.

OK

I will change the o2 sensor at the same time

[This message has been edited by zobari (edited 11-14-2018).]

Trueleo? You may want to go with a heated O2 sensor since you went this far. See link.

https://www.fiero.nl/forum/A...100421-2-090504.html

Spoon

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"Kilgore Trout once wrote a short story which was a dialogue between two pieces of yeast. They were discussing the possible purposes of life as they ate sugar and suffocated in their own excrement. Because of their limited intelligence, they never came close to guessing that they were making champagne." - Kurt Vonnegut

quote Originally posted by edfiero: Unless you plan other modifications that will significantly increase your horsepower, you will likely see no gains by going to a larger diameter exhaust.

Exactly and that's even if you port the somewhat restrictive intake manifold.

------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

I have found a person who demand me 500$ to make the full Exhaust with muffler and without cat and 2" pipe.

My question what is the best muffler size for good sound not too much loud but sufficiently loud any idea ?
The avalaible kind of muffler is like borla s type round

I have installed a custom stainless Steel 2" pipe with a small round muffler same thing as a universal borla s type 30cm.
The problem is the sound is too loud and too agressive after 2500rpm. On the highway the sound is too loud in the cabin.

I Will change the muffler by a bigger 50 cm. I hope that the sound Will decrease on db and bass frequency.

[This message has been edited by zobari (edited 12-02-2018).]

quote Originally posted by zobari: I have found a person who demand me 500$ to make the full Exhaust with muffler and without cat and 2" pipe. My question what is the best muffler size for good sound not too much loud but sufficiently loud any idea ? The avalaible kind of muffler is like borla s type round

I put the two inch version of this:

https://www.summitracing.co...-493JeEaAr3xEALw_wcB

on my car (mounted it where the cat use to be) and I could not be happier with the way it sounds. The car makes some amazing pops and burbles, is no louder than a big pickup truck at idle, is not too loud unless you are really into it and does not drone on the freeway. I can upload a picture of it if you want to see where and how I mounted it.

Thanks.
Could you upload some pictures please I am very interested.

I have a question.
A round stainless less muffler is a muffler or resonator ?

This item is a resonator or muffler for you :
https://www.ebay.co.uk/itm/...?hash=item4b54793c1b

The seller use muffler and resonator words.
If i use a bigger one the sound level will decrease or not ?

Thank you

i've drove the car several km and the exhaust sound is beautiful with this 30cm round muffler catless.
a bit very loud at 3000rpm on the higway but in the other rpm the sound is crazy and very good.

I don't change the exhauxst, i will probably keep this exhaust configuration.

[This message has been edited by zobari (edited 12-06-2018).]