3 Inch Exhaust Prado TD

Submitted: Tuesday, May 17, 2005 at 09:40
ThreadID: 23053 Views:6124 Replies:4 FollowUps:3
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Spoke to a few exhaust fitters at a recent 4WD and Camping Show. The suggestion was made to fit a 3 inch system with a larger waste gate would reduce turbo lag and provide a few other power/torque improvements as opposed to a standard system.

Has anyone fitted similar system to a Prado TD and did it indeed produce improvements?

Gold Coast
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Reply By: Coops (WA) - Tuesday, May 17, 2005 at 11:19

Tuesday, May 17, 2005 at 11:19
unless you're flat to the floor all the time I would think that 3" is too large. 2.5" should suffice and is the advice I've been given
AnswerID: 111595

Reply By: Member - Chris M (QLD) - Tuesday, May 17, 2005 at 12:38

Tuesday, May 17, 2005 at 12:38
Gday mate,

You need to sustain a certain amount of back pressure. By running too big an exhaust, you lose that effect along with the efficiency of your turbo and your back to square one. Best to talk to a mob (Denco/Brisbane Turbos etc) for the best setup.


AnswerID: 111607

Follow Up By: Wizard1 - Tuesday, May 17, 2005 at 13:05

Tuesday, May 17, 2005 at 13:05
Thanks for the tip, I'll give Denco a call.
FollowupID: 367968

Follow Up By: Member - Captain (WA) - Tuesday, May 17, 2005 at 23:09

Tuesday, May 17, 2005 at 23:09
Hi Chris

Glad to see your back and online. Now, everyone talks about the loss of backpressure in a bigger exhaust and its effect on bottom end, but to my way of thinking, the way a turbo operates is the bigger the difference in pressure between the inlet and outlet of the turbo, the greater the performance of the turbo. While I agree there is probably virtually no pratical gain between a 2-1/2" and a 3", I cannot see it being worse. You know from your experience that replacing the dump pipe gave arguably the biggest gain as it was the biggest restriction.

It reminds me of when I got extractors and 2-1/2" for my 80 diesel. Everyone reckoned while I would gain top end performance, I would lose bottom end. Well, by the seat of the pants that was true, but I had it dynoed before and after and what really happend was the top end gain was much better than the bottom end gain, so it "seemed" like bottom was worse but fact was bottom end improved marginally while top end gained around 15%.

Anyway, i don't know the answer for sure for turbos, but I don't think the myth of needing back pressure is true for turbo diesels. Especially in light of my 80's extrctors experience.


FollowupID: 368083

Reply By: Member - Phil G (SA) - Tuesday, May 17, 2005 at 14:21

Tuesday, May 17, 2005 at 14:21
A couple of guys have done this on the Prado groups. The gains are very limited, as the exhaust is already pretty efficient and this diesel motor is electronically controlled. If you want more performance save a bit more and buy a Dtronic or similar.

AnswerID: 111622

Follow Up By: Wizard1 - Tuesday, May 17, 2005 at 15:21

Tuesday, May 17, 2005 at 15:21
already have the Dtronic, but they don't get rid of all the turbo lag on take off. Contacted a Brisbane Turbo and they agree that 3 inch is too big and that there is no gain but a loss at the bottom end.

Thye have suggested a 2.5 mandrel exhaust (standard waste gate) with a boost control valve. Seems the onwer did his and it worked a treat. Aparently the Dtronic is also part of their upgrade pack, so I'm part the way there.


FollowupID: 368000

Reply By: kev.h - Tuesday, May 17, 2005 at 22:24

Tuesday, May 17, 2005 at 22:24
have a look at this site and talk to them they seemed to know exhausts their new design muffler is of interest, saw them at a trade show ph 1300867839 or
cheers Kev
AnswerID: 111713

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