3" dump pipe
Submitted: Tuesday, Aug 26, 2008 at 10:50
ThreadID:
61096
Views:
3272
Replies:
5
FollowUps:
3
This Thread has been Archived
al
hi all
i keep reading about people putting a 3" dump pipe on there cars i'm just wondering is there any great improvement in performance or fuel savings and do have to replace all of the exhaust system to match. i have a GQ 4.2 diesel with aftermarket turbo do you think this would perform better with one.while i have your ears my turbo is running about 7 pound boost what do you guys think a safe maximum boost to run. the guy that looks after my turbo is reluctant to boost any higher says car is happy were it is the motor is in good nick had a recent over haul 20,000 k's ago don't know why he won't boost higher. any comments would be appreciated.
regards
al
Reply By: Member - Doug T (NT) - Tuesday, Aug 26, 2008 at 10:59
Tuesday, Aug 26, 2008 at 10:59
Keep listening to your guy....
.
AnswerID:
322244
Reply By: Member - Roachie (SA) - Tuesday, Aug 26, 2008 at 11:20
Tuesday, Aug 26, 2008 at 11:20
If it's an aftermarket turbo, chances are it already has a decent sized dump pipe on it.
The problem comes from OE turbo's where the manufacturer installs a cast dump pipe that has an internal orofice about the size of a bloody pea!!! (maybe a slight exaggeration, but you get the drift).
All those gases are trying to get out through the restricted hole.
As for the boost, I do think that 7psi is erring on the conservative side of things a bit too much. It would depend a bit on what year/model your GQ is. The GQ (TD42) originally had heavy duty pistons fitted (1989 to about 1996) and if your vehicle fits into that category, you'd be safe enough to increase the boost to say 11 or 12psi; no worries at all. If it's 1996 or later, I'd be leaving it alone or maybe increasing by 1 to 2 psi at the most.
There are plenty of blokes with GU's that have wound the boost up to 15psi with no long-term ill-effects.
Once you do decide to do anything with the boost, I'd suggest fitting a pyro and boost gauge.
AnswerID:
322246
Follow Up By: Member - Mick O (VIC) - Tuesday, Aug 26, 2008 at 20:00
Tuesday, Aug 26, 2008 at 20:00
I thought 10-19 psi was the normal boost for the GU Roachie. When I had the new donk put in
mine, my 4beesurgeon, Aaron (ATOC autos) was reliably informed by Nissan that this was the right range (obviously he rang them as he was concerned it was boosting high). Under normal operation it's sitting between 7 and 12 though, then flicks up to 19-22 under strain. Sometimes I thinks it's a lot easier to remain ignorant and watch the EGT.
Cheers. Mick.
P.S. The washing machine had a hell of a reach. If she ever gets back into the country, I'm dead!!!
FollowupID:
589343
Follow Up By: Member - Roachie (SA) - Tuesday, Aug 26, 2008 at 20:29
Tuesday, Aug 26, 2008 at 20:29
G'day Mick,
Are you sure that was for the 4.2TD? I'm aware that the 3 litre grenade is able to cope with a certain amount of boost pressure above 15psi (up to 30 psi at a peak....which is bloody scarey to me)...... But I am reasonably sure the recommended max for a 4.2TD is about 15 to 16 psi (as a peak).
I'm equally sure that they are factory set to about 8 or 9 psi; but it wouldn't be the first time I've been
well and truly wrong.
Cheers mate and stay safe (is your will up to date?)....hahaha
Roachie
FollowupID:
589351
Follow Up By: Member - Mick O (VIC) - Tuesday, Aug 26, 2008 at 21:38
Tuesday, Aug 26, 2008 at 21:38
You'd be right Roachie. As I said, I'm ignorant (actually stupid would be more apt) and would prefer to live and die by the EGT and boost guage. One day I'm going to sit down and do Diesel 101 I've just got to find the time. I watch the Patrol
forum and I'm convinced some of those blokes could rebuild the grenade using nothing more than a paper clip and packet of matches and a sense of humour, I'm in awe. Very keen on Chaz's OBD monitoring rig so will try my skills at implimenting that to keep an eye on the new "grenade".
Yep will is written and checking all incoming packages for oily residue on wrapping paper and exposed wires!!!
Cheers. Mick
FollowupID:
589379
Reply By: TerraFirma - Tuesday, Aug 26, 2008 at 13:00
Tuesday, Aug 26, 2008 at 13:00
You are showing all the early signs of having the dreaded Horsepower Disease. It strikes when you least expect it, the never ending quest for more power! LOL
Many have had their wallets and their engines killed by the disease, ouch.!
My advise, ignore the urges and keep your vehicle
well maintained across the board and enjoy the long term partnership you may have with her, otherwise divorce her now and buy a more powerful model ready to quench your thirst for POWER.....LOL..!
A wise old man told me this, he became wise the hard way...!
AnswerID:
322265
Reply By: Member - John - Tuesday, Aug 26, 2008 at 16:36
Tuesday, Aug 26, 2008 at 16:36
Check with the after market turbo supplier as to what they recomend the boost be set at. John
AnswerID:
322300
Reply By: Member - Serg (VIC) - Tuesday, Aug 26, 2008 at 22:19
Tuesday, Aug 26, 2008 at 22:19
I have 3” pipe. If would do it again, I will stick to2.5” one – 3” IMHO does not offer that much improvement over 2.5, but create that much headache indeed.
Cheers
SergAC
AnswerID:
322375