Outer Limits 4x4 Board

I want to change my exhaust, however the muffler shop is suggesting 1.5" pipe for the muffler, I have seen some posts that used 2", so I am unsutre hwich way to go. The shop also suggested to keep my current manifold until I am sure it must change. I am looking for more power but i want to keep the torque.

So any help would be appreciated. !!

Go a 2" system.

If they continue to insist that you should only go with a 1.5", then take your business elsewhere.

You WILL notice a good improvement in low end torque with the 2" system, but don't be tempted to go too much bigger.

go for the 2" exhaust - but put extractors on as well. The gains are noticable and well worth the effort IMO.

I have 4 into 1 Wildcats ( ie extractors not headers ) and there have been a few other posts praising their performance and low cost.

so a 2" pipe, with the standard extractor/header and no modifications to the 1598cc engine.

thanks

I'd recommend fitting extractors and leaving the rest of the system standard (providing there's nothing wrong with it?)

I ran mine like this and had a huge improvement in low rev torque with my Hurricane 4-2-1 extractors. I then got the cat back done in 2" pipe with a new muffler etc and lost a lot of the torque. Power at higher revs was improved, but who drives up in those revs all the time????

aarrg, her we go decisions decisions.

From a cost factor, replacing the pipe and barrells is cheaper. To put in an extractor they would have to build one as importing one is waaaaay too expensive.
Still not sure what to do guys but thanks for your help.

Still willing to listen to anymore advice.

The exhaust manifold is a very bad design (you can't actually see how bad until it is removed....) Basically, all four cylinders feed back into each other where they join and then go into a narrowish outlet, so it's not very good for flow.

Your in Barbados?

I would recommend buying extractors from this guy in Oz:

http://cgi.ebay.com.au/Daihatsu-Rocky-G ... dZViewItem

He sent me a set to Cyprus, and suprisingly the postage was not overly expensive. Ask him for a better price, and you never know....


Like others have said; 2" pipe, extractors & reverse flow muffler is a excellent option.

Yup, I am in Barbados, although the shipping may not be too bad the local DUTIES are a killer.

thats all good.......

I managed to swindle the local post office by telling them that this was a "sample".

murcod wrote:I'd recommend fitting extractors and leaving the rest of the system standard (providing there's nothing wrong with it?)

david, did you include a flexable connection when you had your extractors fitted(like the MRT system). do you think they are effective in reducing the potential of cracks etc...

ferguson wrote:

murcod wrote:I'd recommend fitting extractors and leaving the rest of the system standard (providing there's nothing wrong with it?)

david, did you include a flexable connection when you had your extractors fitted(like the MRT system). do you think they are effective in reducing the potential of cracks etc...

I thought flex bellows were a must in nearly all exhaust systems. Without it, you are relying on the exhaust rubbers to take up all movement caused by the engine moving.. and usually the first mount is at the gearbox...

I know on my other car there is a stainless flex pipe staight after the extractors. This greatly reduces the likleyhood of cracks in the manifold area.

Yes, I've got the flex fitted plus a bracket connected to the gear box before it. One of the rear studs on the head (exhuast manifold stud) was sheared off when I went to fit them. No prize for guessing why!

If I let the muffler guys make an axtractor what size pipe should I ask for, and I think the flex would be essential.

BajanFeroza wrote:If I let the muffler guys make an axtractor what size pipe should I ask for, and I think the flex would be essential.

A wrongly made set of extractors would be worse than your stock system!

Extractors have tuned length pipes which promotes gas flow from the outlets.. the pulses from each cylinder feed into the main tube so that the tail of one pulse meets the start of the next pulse, and it kind of drags the following part of gas along the tube.

If you mess up this, you can have worse performance/economy than before.

Never an easy and cost effective solution together is there.

HotFourOk wrote: A wrongly made set of extractors would be worse than your stock system!

If you mess up this, you can have worse performance/economy than before.

Trust me, they'd have to do a complete balls up of it for them to turn out worse!

The pipe diameter should be matched to the outlet size of the exhaust ports on the head. The ports are "squared" so the pipe will need to be crushed into that shape.

BTW a place that knows how to make extractors shouldn't be asking you those sort of questions! They should be telling you what is best.

They didn't ask , I did.
Need to go chat with them and get a price for extractors only now.

You don't need a flex joint in RWD vehicles. Front wheel drive yes, RWD no. I havnt had one on any of my cars in the past, all of which have aftermarket exhausts and have never had an issue with exhausts cracking.

What's the difference in having FWD, RWD or 4WD?

The motor is still going to rock and shake when running.

i agree with Rb25sil80. on a north/south mounted engine the exhaust system rocks with the engine, side to side. the feroza for example has the headers, the first section or pipe bolted to the gearbox (moves with engine rock), then the rest of the system has rubber mounts which let the system move.

east/west mounted engines like in my mr2 the engine rocks back and forth against the north/south mounting direction of the exhaust system, therefore must have a flex pipe.

a flex pipe will only move in a up/down bendy way, it doesnt twist.

So the comment should've been transversely mounted engines require a flex bellows more so than a longitudinally mounted engine?
Rather than just generalising to FWD and RWD

I've had an exhaust manifold stud snap (and thats with the standard manifold and gearbox bracket- it was the rear most stud), so I'd recommend the flex. It's only around $40 so hardly worth scrimping on.

If you get your exhaust caught up on something off road it could save the extractors/ studs. Also, the exhaust system is hanging way off to one side on the engine and therefore does not just twist when the engine rocks- there will also be sideways / up / down force on the entire exhaust system.

The flex joins can also help reduce noise being transmitted into the cabin.

Also, the twisting of the chassis when offroad can cause exhaust issues if no flex bellow is used

Good point about reducing the resonance into the cabin too Murcod

murcod wrote:It's only around $40 so hardly worth scrimping on.

doesn't sound like there's a real down side to putting one in anyway... true?

HotFourOk wrote:So the comment should've been transversely mounted engines require a flex bellows more so than a longitudinally mounted engine?
Rather than just generalising to FWD and RWD

No I stand by the comment. How many rear wheel drive cars do you know of with east west facing motors? There are some mitsubishi engines that are AWD that face east west but I dont know of too many RWD cars with East West motors. So your post just seems like your nitpicking

Tufferoza thanks for elaborating for me

But as said by Murcod. $40 is not a great deal of crust for a little extra insurance, even if you dont really need it!

Cheers

Get a flex section put in if you can. Mine didn't have one and it broke the exhaust "O" ring between the down pipe and the cat over the weekend.
Going to get one put in this weekend.

When the going gets really heavy its surprising just how much the engine moves around and how much stress this puts on the exhaust.

I am wondering if most these broekn exhaust problems relate to broken engine mounts and gearbox mount.

I never had a flex joint on my old Feroza and never had an issue with exhaust cracking, although i was replacing engine/gearbox mounts frequently.

All true about engine mounts - but mine has all new mounts (and you can guess what the state of the old ones was... ) but it still spat out the exhaust centre "o" ring thingy....

Was trying hard so its not going to be an everyday thing - but its the second one I have gone through.

r0ck_m0nkey wrote:I am wondering if most these broekn exhaust problems relate to broken engine mounts and gearbox mount.

I never had a flex joint on my old Feroza and never had an issue with exhaust cracking, although i was replacing engine/gearbox mounts frequently.

Ditto,..........