Most suitable sized exhaust for 4age 16/20v

[Dom-AE71]

what are everyones opinion for the best sized exhaust? i want the car to be legal as far as sound levels are concerned but i still want it to flow well and not be restrictive. for engineering and emmisions ect i will be using a cat.

i know a few of the ae86 guys use 2.5" with their 20v's but i reckon thats too big?

i was thinking a 2.25" system with possibly a 2.5" cat would work well?

anyones input?

thanks

[roadsailing]

have you searched? this has been covered 11ty billion itmes.

my thoughts.

standard engine - 2 inch system with mandrel bends. i don't buy into the whole "use bigger pipe and use press bends" theory.

"worked" maybeye 2.25 inch.

light turbo or 4AGZE running an SC14 and bossted to silly amounts - 2.5 inch.

maximum effort turbo - 3 inch, maybeye dual 2 inch.

make the reducer/expander to the cat as gradual as possible, and use good quality stainless steel for all of the piping.

by the way, thanks for not mentioning "backpressure"

[Ta2272]

i would just go with a 2.25 bench pressed exhaust, i dont think there would be a large difference either way.

Extracters, i dont really know what the difference is but different kinds are meant to achieve better low/high end power, ei, 4-1 or 4-2-1 thought i again think the results would be very marginal.

Jason

[Dom-AE71]

yea i searched the old forums but nothing was really specific that i could find to RWD 16/20v applications, in particular 20v becuase thats whats going into my ke55

[Dom-AE71]

so are you saying a 2.25inch mandrel bent exhuast would be too big?

like i said i want the car to be legal, which includes height clearance so the exhaust will be going up and over the diff but mandrel bends will be used to do this as not to affect sizing

[EldarO]

a mate has a Jap Spec 4AGE ke70, retaining the stock ke70 exhaust from cat back, its something rediculous like 1.5"

i will admit, it would give my supra a run for its money.

Eldar.O.

[mrshin]

I'll bet it sounds like something Electrolux might produce...

[parrot]

When I did mine I asked for 2 1/4 inch pressed presuming this would effectively be 2 inch. When I picked it up they had done 2 1/4 mandrel. What's it like? With a Lukey muffler and high flow cat it is pretty noisy but O.K. in comparison to the stupid mufflers you see around these days. What noise there is is nice, not droning. I am planning to pull the cat out soon. Differences in power (cams, head, compression etc) no idea, clearance with King springs no problem, but was done properly.

[The Witzl]

My AE71 had a 2" press bent system with resonator and redback muffler (iirc).... no cat.... 4-1 extractors on a smallport 16V.

It sounded good, but was often too noisy. I wouldnt get anything bigger - it's only a 1.6L after all!!

[andy]

i have a 2.25" press bent on my silver 20v. its a very well made system, and the primaries are as long as can be, joining just before the flex pipe. the guy who made it did an awsome job.
put on a 2.25" high flow cat which shit itself 2 weeks ago and got it replaced for a free-er flowing one on the weekend. the new one is steel core and is usally used on the down pipe on wrx. the car has gotten pretty loud cos of this and im not v happy as i will be getting the bends changed to mandrel bends this sat and then it may be too noisy. i have a tri flow muffler and a resonator, all 2.25".

should i get the mandrel bends put in or not?

[Dom-AE71]

so 2inch mandrel bent would be a goer?

im thinking to be a tight arse and save money jsut chuck my old 2inch system back on i have sitting in the garage, it was too big and loud for the old 4k but by the sounds of things should be good enough for the 20v.

[oldcorollas]

although pipe size does affect the sound level and quality, your resonators and mufflers have a much larger effect than the pipe size.

dom, as an example, on my 4K i had 2", with mandrel over diff. i also had 2 well contructed resonators, one just behind gearbox (immediately after collector), and one just before the diff. the muffler was the largest volume i could fit in the space, was reverse flow, 2", but still flowed very well. the resonators and mufflers were ESA brand, and bloody cheap ($100 for all three). at 8000rpm the exhaust side of things was still pretty quiet. it never droned, wasn't raspy.... no annoying sounds... but everyone says 2" is too big for a 1.3

so, after the collector, 2.25 or 2.5 will make not much difference to noise if you muffle it well. mandrel over the dif is good. the other bends are not sharp (after proper extractors) so don't matter so much)

as for cats, there are hiflo and highflow if they have the same design of core, get the one with the largest core cross-sectional area. an identical core with different pipe size is still going to flow same (just something to look for and compare). resonators make a big difference. punched and louvred holes are not so good.. you want good quality construction with holes that look drilled (not actually drilled, but not so they bend the metal and cause louvring, with louvre, one way causes restriction the other does buggerall)

with muffler, there is a big range. start by fitting the largest volume muffler that you can. a large volume helps to reduce noise IF internal construction is good. a well constructed large reverseflow muffler will be quiet and not restrict as much as you think. you can go to a larger diameter in/out also, with the aim of increasing the size of the internal passages, whilst still having a large sound reduction. a simple dogleg mufler or straight thru is likely to be much louder. for toyotas sake, don't get a cannon they may be fine on a turbo (since the turbo is a great muffler) but on NA..uh uh..

if he is still there, i would go talk to the head dude at "Australias Best", he helped me with recommendations when i was building mine, and was bloody cheap.

[20valve69corona]

Dom,

I just got a 2 1/4 inch press bent exhaust installed on my 20v corona.

The guy who done the exhaust was saying that he has installed 2 1/4 inch exhaust's on a heap of 20v's.

[Garth AE86]

2.25" for a tuned NA 4A-G

its been proven and tested by toda japan to be the best size for a mild 4age

[4agerolla]

ive got a 2inch mandrel bent system on my 16v... it can sometimes be too loud in the cabin at certain revs.. but i mean it certainly helps the car to breathe a bit better. id hate to see what much bigger diameter pipes would be like inside the car!

my 2cents!