3" exhaust on 3lt turbo nissan
Submitted: Tuesday, Dec 02, 2008 at 18:03
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Member -Carl R (QLD)
Has anybody put a 3" exhaust system on a 3lt Nissan patrol ? could you please let me know the pros and cons
Reply By: Dunaruna - Tuesday, Dec 02, 2008 at 18:27
Tuesday, Dec 02, 2008 at 18:27
Yes, done it on a 3.0 TDi.
Pros, definitely better low down torque. Slightly better economy. Sounds better (throatier).
Cons, The manifold connection needs to be a very tight 90 degree bend, cracking in this area is a problem. Gusseting is difficult due to restricted space but it is doable.
AnswerID:
337902
Reply By: Thermoguard Instruments - Tuesday, Dec 02, 2008 at 18:28
Tuesday, Dec 02, 2008 at 18:28
Hi Carl,
In my opinion, there's no such thing as a 'too big' exhaust system for a turbo diesel so, as long as you can afford it, go ahead.
However, given the not exemplary reputation of the ZD30 engine, I'd suggest you might be better off spending your money ensuring the airflow meter, etc. doesn't lose the plot and seriously overfuel your engine at some stage...
Ian
AnswerID:
337903
Follow Up By: Member -Carl R (QLD) - Tuesday, Dec 02, 2008 at 19:23
Tuesday, Dec 02, 2008 at 19:23
Is there some way of ensuring the air flow meter is working?
FollowupID:
605451
Reply By: MrBitchi (QLD) - Tuesday, Dec 02, 2008 at 19:16
Tuesday, Dec 02, 2008 at 19:16
Given the relatively low revs a diesel achieves compared to a petrol, there's no way a 3" is necessary. It may even be counter productive. My 3.5 LT petrol has a 2.75" mandrel bent system as specified by
Beaudesert Exhausts and that is the max it could ever use. A 3lt diesel would never NEED more then a 2.5" system. It simple does not move that much air.
If you do go ahead with it, it would be interesting to get before and after dyno and economy figures.
AnswerID:
337912
Follow Up By: Isuzumu - Tuesday, Dec 02, 2008 at 20:11
Tuesday, Dec 02, 2008 at 20:11
Have to differ there John, last boat I built had a couple of 4 cylinder Yanmars 230HP the exhaust coming out of the turbo was 6 inch and then into an 8 inch pipe going out of the vessel. This is a 3.45 litre motor and that's how they get this sort of HP and that HP achieved at 3400RPM.
Cheers Bruce
FollowupID:
605460
Follow Up By: Malleerv - Tuesday, Dec 02, 2008 at 20:21
Tuesday, Dec 02, 2008 at 20:21
My understanding is that the larger the exhaust after a turbo the quicker and easier it will spin up and boost due to exhaust gas flowing away easier ie: less back pressure. Petrols are a little different and need some back pressure to stop unburnt fuel passing through the cylinder.
Matt
FollowupID:
605463
Follow Up By: Isuzumu - Tuesday, Dec 02, 2008 at 20:24
Tuesday, Dec 02, 2008 at 20:24
Dead right there Matt. Have a 3 inch on my 3.1Lt MU made a big difference.
Cheers Bruce
FollowupID:
605465
Follow Up By: Stiphodon - Tuesday, Dec 02, 2008 at 20:38
Tuesday, Dec 02, 2008 at 20:38
I have to disagree too, I have a 2.8td rodeo and putting a 2.5" exhaust from the turbo and combined with a fuel pump adjustment it was the single biggest improvement I could have made, went from around 51hp to 74hp on the dyno. The larger exhaust also allowed the turbo to spool up easier and boost went from 9psi to 11psi
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Follow Up By: MrBitchi (QLD) - Tuesday, Dec 02, 2008 at 21:06
Tuesday, Dec 02, 2008 at 21:06
My understanding is that is what a larger dump pipe is for, better response from the turbo. A 3" dump pipe is a common mod but that doesn't go all the way to the back...
Stiphodon, a 2.8lt is ALMOST the same as a 3lt. As you say a 2.5" exhaust is great. I still think a 3" would be overkill.
FollowupID:
605477
Follow Up By: Member - John - Wednesday, Dec 03, 2008 at 05:17
Wednesday, Dec 03, 2008 at 05:17
John, have to differ also, have done before and after dyno figures on standard and 3" exhaust, 2.8 TD and 4.2 TD (nissans) and in both cases torque and HP figures where up. Boost came on earlier also.
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605528
Follow Up By: MrBitchi (QLD) - Wednesday, Dec 03, 2008 at 09:07
Wednesday, Dec 03, 2008 at 09:07
Guys, I'm not disputing that a 3" is better than standard, but I still maintain that you could achieve the same benefit using a 2.5" system for considerably less dollars.
Back to back numbers with a 2.5" and 3" system would be very interesting...
FollowupID:
605544
Follow Up By: Goona - Wednesday, Dec 03, 2008 at 21:54
Wednesday, Dec 03, 2008 at 21:54
John,
I have a 3 inch system and from what I have been told is that at the back of the Nissan Turbo housing it is 3 inch. Nissan run a 2 1/4 from there which is very restrictive. The 3 inch is better as this creates less turbulence and spools up a lot quicker. A Mate of
mine Turboed his 4.2 1HZ motor and started with a 2 1/2 system but changed to a 3inch system and there was an improvement but I can't recall the exact figures.
Goona
FollowupID:
605662
Reply By: Bonz (Vic) - Tuesday, Dec 02, 2008 at 21:01
Tuesday, Dec 02, 2008 at 21:01
Yep I got one on
mine. 3" mandrel bent Taipan XP exhaust
Pro's
- 13% more power at rear wheels on the dyno (when combined with a K&N hi flow filter)
- Turbo spools up faster
- sound is slightly more beefy
- Heat gets away quicker (more relaxed on the granade issue)
Cons
- Price
AnswerID:
337947
Reply By: blown_zd30 - Wednesday, Dec 03, 2008 at 10:50
Wednesday, Dec 03, 2008 at 10:50
Hi Carl
Have recently installed a 3" mandrel bent system with hi-flow cat and hi-flow muffler. Wish I had done it years ago.
Turbo definitely spools up quicker, small-ish but definitely noticeable increase in power. Could be further improved with a programmable power chip.
Did suffer a surging drone type noise from the engine after install which was fixed by installing a hi-flow ITG air filter as it was seriously starving for air. Have also considered a larger truck type head on
snorkel to stuff more air into it.
Helped with towing the camper and certainly pulls up hills more easier.
Didn't improve fuel economy as it does drink more diesel now but
well worth it.
Oh, and sounds good too with no noticeable increase in the cab.
Cheers
Brad
AnswerID:
338016
Follow Up By: patrolmann - Wednesday, Dec 03, 2008 at 13:59
Wednesday, Dec 03, 2008 at 13:59
Hi guys,
I have a GQ 2.8 lt td patrol and just had a 3inch mandrel bent semi stainless fitted from the back of the turbo to the back end. Wow makes a huge diff. The 2.8,s are known for the lack of power off the line especially when towing the camper but this has made a huge difference. Much more low grunt and turbo spools up much earlier
Had
mine done by Mark at Exhaust Goodwood SA.
Best money i have spent. I had problems with it running warm when towing as
well and it seems to have helped the temp. as
well.
Maybe that's just my imagination but as the summer approaches I shall see I guess.
cheers
Patrolman
FollowupID:
605570
Follow Up By: Member - Malcolm C (QLD) - Wednesday, Dec 03, 2008 at 16:42
Wednesday, Dec 03, 2008 at 16:42
[[ Have also considered a larger truck type head on
snorkel to stuff more air into it. ]]
Just wondering if anybody has tried those HICLONE thingos in their ZD30 air system (takes two). Spins the air and gets better throughput I believe.
Malcolm
FollowupID:
605591