• Advertisement

2.5" Dump pipe for 4JB1T

Getting the best performance from your Isuzu, the in's and out's

Re: 2.5" Dump pipe for 4JB1T

Postby geeves » Wed Apr 08, 2015 8:08 pm

Its going to cost half what adding the dump pipe will and you still get very usable gains. I cant give actual numbers though but my 2.8 bighorn ran a press bend 2.5 inch pipe from the flex pipe back and went very well.
Sanding your knuckles before starting work can help. That way you cant skin them
User avatar
geeves
Site Admin
 
Posts: 8131
Joined: Sun May 10, 2009 1:36 pm
Location: wellington
Age: 55
Country: NZ
City: Wellington
Vehicle: 94 bighorn
96 wizard

Re: 2.5" Dump pipe for 4JB1T

Postby Downhillnz » Thu Apr 09, 2015 5:06 am

lucasks82 wrote:I have been to a local exhaust shop and he suggested just doing a 2.5" exhaust from the existing 2" dump pipe.

Is that a good idea?

I mean wont it constrict the air flow right from the turbo and negate some of the benefits of having a big bore straight through exhaust?


Yes. I mean it would help, but if you are in the exhaust shop and getting a full exhaust made you may as well get the dump pipe made at the same time. Its a noticable difference down low.
Downhillnz
Isuzu Junior
 
Posts: 136
Joined: Thu Aug 07, 2014 10:47 pm
Age: 22
Country: Nz
City: Nelson
Vehicle: 1992 Isuzu Mu 2.8TD
1997 Toyota Corolla 1.5TD

Re: 2.5" Dump pipe for 4JB1T

Postby SamMu93 » Sat Apr 18, 2015 8:42 pm

Hi guys, click here http://www.clubisuzu.com/viewtopic.php?f=19&t=6751 to see where I'm at with my 4jb1t build- it will answer most of your questions...
Also here's a few more pics
One of which is the factory dump pipe - note the quick warm up valve that should be reason enough to rip it out!
You do not have the required permissions to view the files attached to this post.
Last edited by SamMu93 on Sun Aug 02, 2015 7:37 am, edited 1 time in total.
SamMu93
Isuzu Junior
 
Posts: 140
Joined: Sun Jan 18, 2015 3:22 pm
Age: 29
Country: New Zealand
City: Wellington
Vehicle: 93 Isuzu Mu 2.8 TD
Rodeo 3" dump pipe off turbo
2.5" Exhaust to tip
Bighorn intercooler
Tweaked fuel pump
Boost tap (15psi)
Egt monitor installed
Rear: 2" lifted leaf springs
Front: Wound torsion bars, dropped front diff, flipped ball joints, cut upper bump stop

Re: 2.5" Dump pipe for 4JB1T

Postby SamMu93 » Sat Apr 18, 2015 8:45 pm

It's at this point that you will notice the issue now on your hands... Time to find an oil filter housing off a 4jg2 3.1...
You do not have the required permissions to view the files attached to this post.
SamMu93
Isuzu Junior
 
Posts: 140
Joined: Sun Jan 18, 2015 3:22 pm
Age: 29
Country: New Zealand
City: Wellington
Vehicle: 93 Isuzu Mu 2.8 TD
Rodeo 3" dump pipe off turbo
2.5" Exhaust to tip
Bighorn intercooler
Tweaked fuel pump
Boost tap (15psi)
Egt monitor installed
Rear: 2" lifted leaf springs
Front: Wound torsion bars, dropped front diff, flipped ball joints, cut upper bump stop

Re: 2.5" Dump pipe for 4JB1T

Postby turnturn » Sun Apr 19, 2015 7:42 pm

The QWS butterfly/shaft and bolts in the exhaust are about 25% of the area of the outlet. I removed them recently from my 4JB1.
You do not have the required permissions to view the files attached to this post.
User avatar
turnturn
Global Moderator
 
Posts: 886
Joined: Wed May 13, 2009 4:26 pm
Age: 51
Country: New Zealand
City: Dunedin
Vehicle: 1992 Isuzu Mu 2.8 Manual (UCS55)
Snorkle, Intercooled
1993 Isuzu Mu 2.8 Manual (UCS55)
Spare Parts/Donor
1994 Isuzu Mu 3.1 Manual (UCS69)
Snorkle, Intercooled
1996 Isuzu Mu 3.1 Manual (UCS69)
Completely Standard

Re: 2.5" Dump pipe for 4JB1T

Postby SamMu93 » Mon Apr 20, 2015 5:36 am

Does anyone know what this is off and if it would fit my 4jb1-t engine?
You do not have the required permissions to view the files attached to this post.
SamMu93
Isuzu Junior
 
Posts: 140
Joined: Sun Jan 18, 2015 3:22 pm
Age: 29
Country: New Zealand
City: Wellington
Vehicle: 93 Isuzu Mu 2.8 TD
Rodeo 3" dump pipe off turbo
2.5" Exhaust to tip
Bighorn intercooler
Tweaked fuel pump
Boost tap (15psi)
Egt monitor installed
Rear: 2" lifted leaf springs
Front: Wound torsion bars, dropped front diff, flipped ball joints, cut upper bump stop

Re: 2.5" Dump pipe for 4JB1T

Postby geeves » Mon Apr 20, 2015 3:05 pm

a link to more than the pic might help
Sanding your knuckles before starting work can help. That way you cant skin them
User avatar
geeves
Site Admin
 
Posts: 8131
Joined: Sun May 10, 2009 1:36 pm
Location: wellington
Age: 55
Country: NZ
City: Wellington
Vehicle: 94 bighorn
96 wizard

Re: 2.5" Dump pipe for 4JB1T

Postby SamMu93 » Mon Apr 20, 2015 3:19 pm

geeves wrote:a link to more than the pic might help


http://www.freewai.com/oil-filter-with- ... -3256.html

Says from a 4jb1 N/a but I'm unsure what model of Isuzu this would be... Any ideas?
SamMu93
Isuzu Junior
 
Posts: 140
Joined: Sun Jan 18, 2015 3:22 pm
Age: 29
Country: New Zealand
City: Wellington
Vehicle: 93 Isuzu Mu 2.8 TD
Rodeo 3" dump pipe off turbo
2.5" Exhaust to tip
Bighorn intercooler
Tweaked fuel pump
Boost tap (15psi)
Egt monitor installed
Rear: 2" lifted leaf springs
Front: Wound torsion bars, dropped front diff, flipped ball joints, cut upper bump stop

Re: 2.5" Dump pipe for 4JB1T

Postby geeves » Mon Apr 20, 2015 5:26 pm

that freewai.com has some reasonable prices for those having difficulty getting parts. Shippings a killer though if you have auto parts stores willing to help.
Sanding your knuckles before starting work can help. That way you cant skin them
User avatar
geeves
Site Admin
 
Posts: 8131
Joined: Sun May 10, 2009 1:36 pm
Location: wellington
Age: 55
Country: NZ
City: Wellington
Vehicle: 94 bighorn
96 wizard

Re: 2.5" Dump pipe for 4JB1T

Postby SamMu93 » Mon Apr 20, 2015 5:34 pm

geeves wrote:that freewai.com has some reasonable prices for those having difficulty getting parts. Shippings a killer though if you have auto parts stores willing to help.


i take it you are registered to that site? Because you cant see the prices until you log in.
If you are how much was that in the link above?
SamMu93
Isuzu Junior
 
Posts: 140
Joined: Sun Jan 18, 2015 3:22 pm
Age: 29
Country: New Zealand
City: Wellington
Vehicle: 93 Isuzu Mu 2.8 TD
Rodeo 3" dump pipe off turbo
2.5" Exhaust to tip
Bighorn intercooler
Tweaked fuel pump
Boost tap (15psi)
Egt monitor installed
Rear: 2" lifted leaf springs
Front: Wound torsion bars, dropped front diff, flipped ball joints, cut upper bump stop

Re: 2.5" Dump pipe for 4JB1T

Postby geeves » Tue Apr 21, 2015 2:59 pm

I registered to have a look at items I have recently bought. They are a little cheaper than Hut city autoparts with currency conversion but not the freight. For the average ball joints etc the answer is local but for someone without a local autoparts store that can be bothered looking isuzu parts up ie Queensland it could be worthwhile
Will look that part up later
Sanding your knuckles before starting work can help. That way you cant skin them
User avatar
geeves
Site Admin
 
Posts: 8131
Joined: Sun May 10, 2009 1:36 pm
Location: wellington
Age: 55
Country: NZ
City: Wellington
Vehicle: 94 bighorn
96 wizard

Re: 2.5" Dump pipe for 4JB1T

Postby geeves » Tue Apr 21, 2015 4:45 pm

$77 plus $50 freight both US$ and thats not the one your looking for
I would be trying Motex or Wn Van and Ute as they may of had a vehicle with a blown engine
Sanding your knuckles before starting work can help. That way you cant skin them
User avatar
geeves
Site Admin
 
Posts: 8131
Joined: Sun May 10, 2009 1:36 pm
Location: wellington
Age: 55
Country: NZ
City: Wellington
Vehicle: 94 bighorn
96 wizard

Re: 2.5" Dump pipe for 4JB1T

Postby SamMu93 » Tue Apr 21, 2015 6:09 pm

geeves wrote:$77 plus $50 freight both US$ and thats not the one your looking for
I would be trying Motex or Wn Van and Ute as they may of had a vehicle with a blown engine


Seems like a good price if its new- Ive been informed that my second hand 4jg2 oil filter assembly is in the post so should turn up tomorrow or thursday :D
SamMu93
Isuzu Junior
 
Posts: 140
Joined: Sun Jan 18, 2015 3:22 pm
Age: 29
Country: New Zealand
City: Wellington
Vehicle: 93 Isuzu Mu 2.8 TD
Rodeo 3" dump pipe off turbo
2.5" Exhaust to tip
Bighorn intercooler
Tweaked fuel pump
Boost tap (15psi)
Egt monitor installed
Rear: 2" lifted leaf springs
Front: Wound torsion bars, dropped front diff, flipped ball joints, cut upper bump stop

Re: 2.5" Dump pipe for 4JB1T

Postby geeves » Tue Apr 21, 2015 6:37 pm

new but non genuine. Might not be an issue.
Sanding your knuckles before starting work can help. That way you cant skin them
User avatar
geeves
Site Admin
 
Posts: 8131
Joined: Sun May 10, 2009 1:36 pm
Location: wellington
Age: 55
Country: NZ
City: Wellington
Vehicle: 94 bighorn
96 wizard

Re: 2.5" Dump pipe for 4JB1T

Postby MuZILLA » Sat Oct 10, 2015 11:12 pm

turnturn wrote:The QWS butterfly/shaft and bolts in the exhaust are about 25% of the area of the outlet. I removed them recently from my 4JB1.


What did you use to plug the holes on the downpipe?
MuZILLA
Isuzu Baby
 
Posts: 18
Joined: Fri Aug 14, 2015 1:55 pm
Age: 22
Country: Australia
City: Perth, WA
Vehicle: ISUZU MU 1991 2.8TD

Re: 2.5" Dump pipe for 4JB1T

Postby turnturn » Sun Oct 11, 2015 2:59 pm

I just machined up a plug that utilised the existing mounting threads. You can sort of see it in the top photo in my post above.
User avatar
turnturn
Global Moderator
 
Posts: 886
Joined: Wed May 13, 2009 4:26 pm
Age: 51
Country: New Zealand
City: Dunedin
Vehicle: 1992 Isuzu Mu 2.8 Manual (UCS55)
Snorkle, Intercooled
1993 Isuzu Mu 2.8 Manual (UCS55)
Spare Parts/Donor
1994 Isuzu Mu 3.1 Manual (UCS69)
Snorkle, Intercooled
1996 Isuzu Mu 3.1 Manual (UCS69)
Completely Standard

Re: 2.5" Dump pipe for 4JB1T

Postby damo667 » Thu Sep 08, 2016 9:12 pm

I'm thinking of removing the QWS butterfly from my dump pipe, just wondering how much work is involved?

Failed a wof on my Flexible Joint, The rear section of my exhaust is already 2.5" so I'm going to get him to replace the rest with 2.5", up to the down pipe

I guess I'll have to unbolt the manifold from the block and maybe unbolt the turbo?

Then once I've got it out grind/unbolt/smash the butterfly valve out and fill the holes left behind?

Just wondering if anyone here has done it and has any advice or can see something I'm missing something out?

Cheers in advance

Damo
vroom..._____________...........
vroom./---------|--------\.......
..&.....||______|_____O-\______....
....&...|--____---------------____--\..
........=\/-----\__________/-----\_|...
............\___/..................\___/...
User avatar
damo667
Isuzu Senior
 
Posts: 246
Joined: Fri May 27, 2011 12:27 pm
Age: 31
Country: new zealand
City: queenstown
Vehicle: 1990 Bighorn 2.8D Irmscher LWB
Roof rack,
31/10.5/15 Hankook Dynapro AT-M tyres,
6" speakers front and back, Sony head unit,
DIY Snorkel & K&N cotton filter,
Boost,EGT gauge
Adjusted boost,
Adjusted fuel,
High-flow muffler 2'5" pipe
2" suspension lift
EFS shocks

"the little rihno"

Re: 2.5" Dump pipe for 4JB1T

Postby geeves » Fri Sep 09, 2016 5:38 am

Some people have just undone the bolt removed the flap and put the bolt back but a cleaner way is to take it out and weld up the 2 holes
Sanding your knuckles before starting work can help. That way you cant skin them
User avatar
geeves
Site Admin
 
Posts: 8131
Joined: Sun May 10, 2009 1:36 pm
Location: wellington
Age: 55
Country: NZ
City: Wellington
Vehicle: 94 bighorn
96 wizard

Re: 2.5" Dump pipe for 4JB1T

Postby pig75 » Fri Sep 09, 2016 6:37 am

I Just used welsh plugs to fill the holes on my 4jb1
92 MU, 91 MU ute, 90 MU, 96 Wizard,2012 Dmax LSU, 14 MUX
Australia's loudest MU
MY SITE MY YouTube SPL 152.3dB
If beef is in beef mince, What is in pet mince?
User avatar
pig75
Site Admin
 
Posts: 1450
Joined: Sat May 09, 2009 7:38 am
Location: Proston
Age: 49
Country: Australia
City: QLD
Vehicle: 90MU, 91MU ute & 92MU, 96 Wizard, 2012 Dmax LSU, 2014 MUX LST

Re: 2.5" Dump pipe for 4JB1T

Postby damo667 » Sat Sep 10, 2016 10:41 am

Cheers guys, are welch plugs easy to use?
I dont know if my welding is up to the job. :oops:
I was originally thinking maybe I could tap in some bolts?
vroom..._____________...........
vroom./---------|--------\.......
..&.....||______|_____O-\______....
....&...|--____---------------____--\..
........=\/-----\__________/-----\_|...
............\___/..................\___/...
User avatar
damo667
Isuzu Senior
 
Posts: 246
Joined: Fri May 27, 2011 12:27 pm
Age: 31
Country: new zealand
City: queenstown
Vehicle: 1990 Bighorn 2.8D Irmscher LWB
Roof rack,
31/10.5/15 Hankook Dynapro AT-M tyres,
6" speakers front and back, Sony head unit,
DIY Snorkel & K&N cotton filter,
Boost,EGT gauge
Adjusted boost,
Adjusted fuel,
High-flow muffler 2'5" pipe
2" suspension lift
EFS shocks

"the little rihno"

PreviousNext

Return to Engines and Exhaust

Who is online

Users browsing this forum: No registered users and 2 guests