does size count?

[Heath]

Okay crunch time.

I have saved for the new exhaust and its time to make a firm decision on what size. I have an intercooled turbo 3 litre diesel (1kz-te, SWB Prado) and am going to replace everything from the turbo flange back (new dump pipe and exhaust with free flow muffler and mandrel bends). This is my daily driver so I dont want something that will drive me insane with droning or be too loud. I want something that will get the heat away from the engine block as quick as I can and hopefully increase turbo spooling a little. Been told that a better exhaust wakes these little diesels up (Kbush has shown this to be true), but what size?

Toying with going to 3" and be done with it, but would 2.5" be enough?

Is there a price difference between the two sizes or are they similar?

So what do ya think ORE? Is size important?

[Lynx]

I went with 2.5, because of personal experience.

Cheers Daniel

[wopass]

bigger is better, get the zaust out as fast as possible!!!

[Heath]

is there an intermediate size - 2.75"? Maybe that's the way to go (bit of compromise)

Bugger just added another option and lost the other votes. Was even then, 3 all (for 2.5 and 3). Didnt know that happened. Never mind

[kbushnz]

This one of those questions like "Whats the best tyre"
I am bias now, go 3 inch.
Even with the cut down exhaust its not too bad in the cab and I don't have any carpet. From the outside its sounds great. Not too loud.
But if you are to compromise, do the dump pipe as its the biggest restriction. Then 2.5 the rest of the way.
Then its set up for 3 inch later...

Calvin

[tallsam66]

2.5 will be fine.....im sure the biggest the dump can be is about 2.5 so not much point going bigger for the rest.

[DieselBoy]

4" bro

Chrome tips hard for the churr

(I like 2" straight through for a 1600cc 4 banger)

[Heath]

4" bro

Chrome tips hard for the churr

(I like 2" straight through for a 1600cc 4 banger)

Gonna need some bling. I can match that to the double overhead chrome grease nipples.

Actually I was thinking of a nice chrome extension for "round town" (and WoF's) and remove it when playing. Might make up a carbon filter or whatever they are to catch sparks too.

Going in to chat to the guys at Al's mufflers on target in the next day or so about details. Anything I should remember? So far I have chrome bling, freeflow muffler (if I bother - Should I bother?) and mandrel 3" system with 3" dump pipe(if it will fit, or I'll step down to the biggest I can get in there) and getting the EGT probe fitted as close to the turbo as I can so it is giving more accurate readings (yeah I know should be in front of the turbo for that, but lets not go there... )
Might get it without the muffler and see how it goes. Can always get one put in if I need to later (save some $$$ too that way I guess).

[Andrew1706]

On a standard vehicle 2.5" might be alright, but if you chuck a 3" exhaust on it would give you room for expansion if you wanted to turn the pump and boost up etc etc

[darinz]

I ran 3" on my old truck and that had over 350kw. A 3" exhuast is also big enough to get about 200rwkw out of a TD42 so I really don't see how you would ever need that much for a 3l. So with the extra cost involved in a 3" I'd stick with the 2.5".

But the 3" will look and sound better so whatever really.

[smurf182]

Agree with the above, I don't see a 3" exhaust being needed for a truck making 130hp.

[Heath]

I think it may come down to costs. if its bugger all difference then 3 inch it is, but if it will save me hundreds the 2.5 (or 2.75 maybe) will be all it gets. Will let ya's know as its going in next week (if I can get it booked in).

[imnotstuck]

i just done a 2.5inch exhaust on my surf, of turbo no mufflers, cost me all up $130 for 2.5 stainless pipe and $40 to get it all welded up, i tacked it up then got it welded

[Heath]

i just done a 2.5inch exhaust on my surf, of turbo no mufflers, cost me all up $130 for 2.5 stainless pipe and $40 to get it all welded up, i tacked it up then got it welded

Fark that's cheap.

I just got a verbal quote for $870 for a full 2.5" mandrel bend system from the turbo back. 3" was going to be another 300 (pitstop quoted me $875 for a 3 inch system a while ago - Hmm)

Had a clamber underneath today and it would apear I have a 2.5 system now (but with all the crush bends and a crappy muffler (with grease from the UJ /shaft slide thingee on it - must see to that soon too) so maybe it will be less if they reuse some of the old straight pipe (yeah, tui moment here I guess).

Mine will be as big a dump pipe as I can get in there (hopefully 3") then will that braced to gearbox with a 3 bolt flange stepped to 2.5" after the join, (a flexi some where around this flange), then a little freeflow muffler (have to have one to get a WoF I am told) and finally out the rear to the usual spot.

Not sure on cost now if they use old bits I might save a little but I dont know. Maybe I'll just get the muffler replaced and get the dump pipe section made for now The bends dont look too restrictive (crushed in) and save for later if required.

I'll admit to being a little bemused by the process (should have done it before when I got the last quote), but we'll see I guess.

[Heath]

Oh and they dont do a 2.75 inch mandrel system.

[lexulance]

Do you know what size the outlet is from the exhaust housing of the turbo?
Theres no point in going to a 3 or 4 inch system if the outlet from the turbo is only 2 inches, you wont get much gain!
There is an after market, complete exhaust housing pipe available that has a 3 inch exit from the housing this makes a huge difference, and also lowers the exhaust temperature aswell?
My brother got one of these for his 1kz and besides the manual pump he had done for it this made the biggest difference out of everything else he did to it, well worth doing

[Heath]

Going to Pitstop down the road from my place and getting a 3 inch system from rear of turbo onwards for 875ish. Good price and they seem okay. Not to mention I get a warrantee which I can use in Chch.

Just some fidling to do to get the right flange as Autobend didnt have any for my wagon in stock.

Can anyone confirm my turbo is a CT12B? If it is then I can specify which flange to use (and maybe they will be able to get one made easier.

[Bulletproof]

Going too big can be worse. On a non turbo it can cause pulsating in the pipe and slow the flow.

Even on a turbo the inside surface area of a big pipe is miles bigger causing drag along the walls with turbulence.

I personally would stick with 2.5 to 2.75 inch and there shouldn't be back pressure.

I run a 2.5 on my supercharged 3 litre hilux.

Cheers Richard

[Heath]

Thought about chasing a smaller pipe (or intermediate one) but figured in the future with a little more boost or a bigger hairdrier (this one might not last forever - not that I want to preempt or curse it in any way) bigger might be better. If I hate it I could always sell it for a low price and get some $$$ back from the deal.

[Heath]

Reposted from another thread:

Had the section from the dump pipe to the exhaust tip done today in 3". Sounds a little rumbly (bit of an echo at the moment), but that may just be me hearing something that I expect to hear. From in th cab it sounds fine, just a little rumble but the tyres cover that noise up.

Got to get the dump done next and I hope it will remove the echo (might be in my head though) in the pipes (could be that 3" is too big as Bulletproof suggested) at idle, at full noise it is fine, a nice low rumble growl.

Have a few things I would like to get done before I get the dump pipe done (injectors and glowplugs) but will get on to it soon as I can rustle up a flange for the rear of the turbo (autobend in Chch dont have any in stock so I have to get one made up here). I am going to see if I can get some steam pipe like Kbushnz (Calvin) used, the exhaust place might hate me but I want it done right and the guy who was doing the work said to stay away from the cheap thin ones as they dont last (he has made a few for his own racecar and only uses heavy gauge steel now). I guess I will chase up bits at northshore steel etc and see what they have in the off cuts bin. Unless of course someone has some bits laying around they dont want.

[Heath]

Bugger, had another huge amount typed and it's dissappeared. Heres the abridged version.

Went well on my evening drive (thrash) up the motor way. Seems to have better pull and spools up quicker so the old muffler wasnt helping.

Have injectors and glowplugs done tomorrow so will replicate my drive tonight and see how it goes.

Dump pipe is still on the cards for in a few weeks at most.

[lincooln]

Hey Heath what colour is you Prado? There is a white on floating round and was wondering if it was yours?

I think I need to get a diesel once i replace my Suzuki. Hopefully that wont be for a while.

Lincoln

[Heath]

Mine is a bluey purple (blurple - toyota classy colours ) SWB one with a black bull bar and grey plastic trim on the sides.

And it now makes a rumbling noise at idle.

[lincooln]

I will have to keep an eye out for it.

at least yours rumbles. Mine just has an annoying rice box sound

[Heath]

I will have to keep an eye out for it.

at least yours rumbles. Mine just has an annoying rice box sound

Dont under estimate the potential inside the smaller zooks. They arent known a giant killers for nothing.

[lincooln]

I know the potential of them, and I love it off road. Getting a locright soon. But will freshen up the engine this spring as its getting on, and I need to fit the hi-flow muffler I bought too.

A guy in the Norwest makes cams, so might see if he can get one made, he has a zuk too, so shouldn't be a problem.

Bit off topic I know

[Heath]

Well afetr a few months I can now say I should have gone with 2.5 inch.

At the time of my decision I was planning on a few future mods but have decised against them now, which makes my exhaust slightly too big (dont for god sake tell the wife I said that).

If I was to do ita all again I would go with a 2.5 inch mandrel system.

Mind you I am still trying to get a turbo flange so I can finish the damn system. Might forget Pitstop as they have been "looking for one" for months now. Pissing me off as I have the steam pipe, the short radius steam bend and the inclination but not the flange to make it all happen. Soon I will loose access to the workshop I wish I had at home (work one) and this will all have to be done by someone else.

To be honest I am not all that happy with Pitstop. They promised a lot and when they finished the job it cost me more than they estimated (didnt get a quote - bugger it - trust is not a comodity to be used in business!) and its not finished. Might bite the bullet and get it finished elsewhere.