What exhaust size ?? 2, 2.5 or 3 inch ??

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Piazzish
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What exhaust size ?? 2, 2.5 or 3 inch ??

Post by Piazzish »

Yepp, What exhaust size should i upgrade to ? Want something better than the rusty stocky exhaust I have now...
2, 2.5 or 3 inch ??

Thanks!
1989 Isuzu Piazza JR120 Lotus Turbo Red 92000km
1989 Isuzu Piazza JR120 Lotus Turbo White 183000km
1987 Isuzu Piazza JR120 Pre-Lotus Turbo Red 131000km
1984 Isuzu Piazza JR130 N/A Two-tone 145000km
1984 Isuzu Piazza JR130 N/A Black 92000km
1989 Isuzu Gemini JT190 Red 173000km
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speedracerles
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Post by speedracerles »

I second that as well....
Isuzu impulse turbo, my weapon of choice!
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Chris
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Post by Chris »

dont go more than 2.5" other wise your another one of those idiots on the road that are loud as hell but hardly able to keep up with a 30ccm Pizza Hutt Scooter.

I have a 2.5 but it came with the car. If it was up to me, leave the excaust systems to V8's and dont bother drawing attention to a 4cyl :D
LESS SHOW, MORE GO!!

2009 | 1986 White Piazza 2.2L, Man, STi Turbo (SOLD)
2006 | 1986 Black Piazza Turbo Manual (SOLD)
2005 | 1986 White Piazza Turbo Auto (Pain in the ass)
2004 | 1986 White Piazza Manual Stock
2004 | 1986 Red Piazza Manual TO3, Haltech
2001 | 1986 Silver Piazza Manual Turbo
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Piazzish
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Post by Piazzish »

yes, I agree! I was thinking of a 2.5, because I think 3" is a little overkill. My brother got one of these for 2.5", he never used it. I think I'm buying it!
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1989 Isuzu Piazza JR120 Lotus Turbo Red 92000km
1989 Isuzu Piazza JR120 Lotus Turbo White 183000km
1987 Isuzu Piazza JR120 Pre-Lotus Turbo Red 131000km
1984 Isuzu Piazza JR130 N/A Two-tone 145000km
1984 Isuzu Piazza JR130 N/A Black 92000km
1989 Isuzu Gemini JT190 Red 173000km
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speedracerles
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Post by speedracerles »

Whats the model number on this part?
Isuzu impulse turbo, my weapon of choice!
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Piazzish
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Post by Piazzish »

155-A014

Nissan - Type A - ID 67mm - Bolt 105-107mm

"The A'PEXi ECV (Exhaust Control Valve) allows you to control the loudness of your exhaust sound. The ECV is installed right after the catalytic converter, and adjustment of the valve is done through a cable run from the cockpit to the valve body. All you have to do is slide the lever installed in the car to get the appropriate sound. With the A'PEXi ECV you'll no longer need to get out of the car to fit a detachable silencer into the tail pipe."
1989 Isuzu Piazza JR120 Lotus Turbo Red 92000km
1989 Isuzu Piazza JR120 Lotus Turbo White 183000km
1987 Isuzu Piazza JR120 Pre-Lotus Turbo Red 131000km
1984 Isuzu Piazza JR130 N/A Two-tone 145000km
1984 Isuzu Piazza JR130 N/A Black 92000km
1989 Isuzu Gemini JT190 Red 173000km
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speedracerles
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Post by speedracerles »

Thanks that sounds like something to think about for my self...
Isuzu impulse turbo, my weapon of choice!
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vinnie55
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Post by vinnie55 »

hello.... That sounds like fun
When you get pulled over for a loud exhaust shut the valve and tell the officer to get a hearing test.

I aggree, anything over 2.5 and you're asking for it.
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speedracerles
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Post by speedracerles »

So what was the price if you dont mind me asking ?
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Piazzish
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Post by Piazzish »

The list price in the USA, is 159$ USD.
1989 Isuzu Piazza JR120 Lotus Turbo Red 92000km
1989 Isuzu Piazza JR120 Lotus Turbo White 183000km
1987 Isuzu Piazza JR120 Pre-Lotus Turbo Red 131000km
1984 Isuzu Piazza JR130 N/A Two-tone 145000km
1984 Isuzu Piazza JR130 N/A Black 92000km
1989 Isuzu Gemini JT190 Red 173000km
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Post by Piazza_man »

I had 3" mandrel bent all the way through. But that was just me wanting to be different. When it came to bragging rights no one could compete. It wasn't loud either due to the turbo and there was droning that you might get with some systems. Cost me about $650 back around 14years ago. I'd do it again if I had another chance. My bro had a 3" system on his Cordia 1.8turbo, and that went hard too. Mind you torque steer was rife (but strangely fun) in that car.

Either way make sure you have a flex tube near the turbo put in.
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Post by IZU069 »

You can never be too big - but you have to do the calcs to see where the peaks are - eg; 2.5"; 3.5"; 6" etc.

I always liked straight through with end fiberglass packing; end plates; else acoustic canceling (but my paper speakers used to burn, and mylar melted).
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Post by Piazza_man »

You're right about doing calcs but I entrusted that to the exhaust guy. I eventually came to realize later on that he wasn't big on maths but was big on creating BIG exhausts on anything turbo that rolled into his workshop. No maths here. But he did one he'll of a job in Canberra. Superb work. I'll give him that much. Doing a big bore install in a Piazza is not an easy task, especially over the rear axle.

While I still had my car I was in touch with another guy who wanted the same system on his car. But he had his done by a reputable mob in Sydney but was disappointed that his system was inferior, with a section of the pipe sitting too close to the ground.

I have a book somewhere re building turbo cars and calculating exhaust systems, etc. It's supposedly like a bible for hard core turbo builders. Bit of a pity I got the book after finishing my car. But like I said before I just had to have the 3" system because I had big plans for getting serious power.
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Post by IZU069 »

My red Piazza has a 3" system.

It was a nice car - new exhaust, air pods, imported Jap turbo engine, and an old lower radiator hose.

(It went the way of my first-ever fully rebuilt rebored & balanced G150 Bellett engine - running it in to a Bellett Car Club (of Vic) meeting at Albury, it ran out.
My bro advised I had steam under the car... Yep - a pinhole in the lower radiator hose.
I didn't even make it back to Melbourne (I did all the usual tricks). Bores were a mess.

It was a similar prick of a story with this Piazza. (Thick as a brick; thin as a pin.)

Hence my "new" rule of all rubbers etc replaced - even if we've been together for a while. (The occasional rebore deserves good rubber.)
The Wasp rebuild of 2000 saw all new hoses & belts (and chains), new waterpump, and pro-checked radiator. Also thermostat and radiator cap.
The advantage was I didn't have to check oil or coolant for several years - I merely replaced oil & filter etc at whatever intervals (5k km?) etc.


So is my 3" exhaust and how I got it a good segway into an experienced tip?
I advised similar with my mate's Piazza - it had been sitting for quite a few years. Although cam & fan belts etc were low kilometrige, I suggested a full hose, cam/fan/etc belt replacement, along with dizzy cap & rotor & splugs, and oil & filter etc.
Any originals that are good can be kept for emergency use. (Just like the original right front wheel-bearing (outer only?) in my Wasp - it is now back in after my new-2000 bearing finally collapsed a few months ago (I knew I should have repacked it after Cooktown!).)

3 years ago I advised a Rodeo owner do similar. One week later they stalled and re-cranked.
Broken cam belt. A guru assured me it would have bent valves (4ZD1 2.3L). Lucky girl - merely replaced the belt - no damage was apparent!



Anyhow, I think 3.5" was ideal for my G200W, but the Florian rejected it on the grounds of clearance - she likes flying over the rough but hates bottoming out. I hate losing exhausts anyhow.
I tried for some flattened exhaust but it was to expensive. I settled for the 2" system. That was $200 400Nm exhaust. (Did I tell you I ended up de-tuning her? Decreased jet size(s) and lowered the float - not recommended for revers, but with ~400Nm, I rarely revved her (except when I required speed instead of acceleration!).


Alas my tuning guru has also left the scene. They were racing Piazza's in NSW but I didn't pay much attention to "those" 4Z thingies at the time - I wasn't into new stuff like Geminis.... er, I mean, the 1980s...
But it was that guru that conveyed the maxima & minima of exhaust (and similar) calcs, and how in ye olden days (pre-Gemini), people tended to stop calculating (iterating) when performance went down.
Alas since the invention of calculus a few centuries back, and the discovery of computers by non-IBM people after the 1950s, we now know that exhausts (etc) have various good sizes (with real bad ones in between).
But we also have those that change carbies or fuel and leave other things as is, or change valve & port sizes and not other breathing.
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Post by Piazza_man »

Yep. Size selection comes down to your current engine specifications, or what you plan on upgrading or planning on in the future. 3" might be an overkill if you have a standard engine/turbo configuration. Otherwise 2.5" system should do fine if you're not that interested in the 'wow' factor.
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