The exhaust system on my '95 NJ needs help. As long as I need to work on it, I thought I'd install headers and a larger mandrel bent system. Apparently this may not improve performance (4X4 low end torque). I get conflicting opinions from my friend/engine builder and another forum:
http://www.4x4wire.com/forums/showflat. ... ost1178662
Does anyone have any real world experience with this?
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3.0L Exhaust Tuning
Moderator: -Scott-
3.0L Exhaust Tuning
1989 MMC/Dodge Raider 5Spd SWB 3.0L NW USA
1995 NJ GLX 5Spd SWB 3.0L SE QLD
1995 NJ GLX 5Spd SWB 3.0L SE QLD
Yes I have first hand experience with a NH lwb 3.0 V6 5sp.
Some of the guys in that thread talk a lot of crap.
Dyno tune before exhaust mods = 77Kw at the rear wheels.
Added Genie extractors, high flow V8 Guppydore cat, high flow muffler with 2.25" system, cost was around $1200 fitted but I had to get some manifold studs replaced as well.
I also had the EFI tinkered with and certain settings adjusted I can't remeber what the techo did exactly.
Dyno tune after mods = 92Kw at the rear wheels
This was with the 34" Simex JT2's fitted and 4.88 diffs.
I was present when both dyno's were done and saw the readings.
The Paj went noticeably better than before more mid range and top end grunt rather than down low. There was a bit more down low but you could definitely feel the extra grunt up at the higher end. It revved out much better/smoother as well.
The system was noisier than before and really barked at high rpm's.
Economy I have no idea as that wasn't a consideration on this Paj.
Some of the guys in that thread talk a lot of crap.
Dyno tune before exhaust mods = 77Kw at the rear wheels.
Added Genie extractors, high flow V8 Guppydore cat, high flow muffler with 2.25" system, cost was around $1200 fitted but I had to get some manifold studs replaced as well.
I also had the EFI tinkered with and certain settings adjusted I can't remeber what the techo did exactly.
Dyno tune after mods = 92Kw at the rear wheels
This was with the 34" Simex JT2's fitted and 4.88 diffs.
I was present when both dyno's were done and saw the readings.
The Paj went noticeably better than before more mid range and top end grunt rather than down low. There was a bit more down low but you could definitely feel the extra grunt up at the higher end. It revved out much better/smoother as well.
The system was noisier than before and really barked at high rpm's.
Economy I have no idea as that wasn't a consideration on this Paj.
I just luv my "clacker Jabber"
I hate to be the middle man, but the theory is over my head. I posted the actual experience on 4X4wire and received this response:
" Quote:
I also had the EFI tinkered with and certain settings adjusted I can't remeber what the techo did exactly.
That sounds rather vague.... I'd really like to know how the "techo" flashed a Gen1 ECU - or what other tinkering allowed for settings to be adjusted.
Quote:
The Paj went noticeably better than before more mid range and top end grunt rather than down low.
That would be expected with headers - but there's no measured torque for the entire curve - only top end. It's also on a truck with 34" tires, helped by the 4.88 gears, but no longer the OE specs at all - and pushing more gaseous volume than the original design parameter, so likely benefiting from a less restrictive exhaust.
Still, a 19.5% increase in HP is great. That would take the 3.0L from 143 to 171HP. At what total cost including the EFI tinkering? And how much of the power increase was related to the "tinkering" and what was tinkered with?"
" Quote:
I also had the EFI tinkered with and certain settings adjusted I can't remeber what the techo did exactly.
That sounds rather vague.... I'd really like to know how the "techo" flashed a Gen1 ECU - or what other tinkering allowed for settings to be adjusted.
Quote:
The Paj went noticeably better than before more mid range and top end grunt rather than down low.
That would be expected with headers - but there's no measured torque for the entire curve - only top end. It's also on a truck with 34" tires, helped by the 4.88 gears, but no longer the OE specs at all - and pushing more gaseous volume than the original design parameter, so likely benefiting from a less restrictive exhaust.
Still, a 19.5% increase in HP is great. That would take the 3.0L from 143 to 171HP. At what total cost including the EFI tinkering? And how much of the power increase was related to the "tinkering" and what was tinkered with?"
1989 MMC/Dodge Raider 5Spd SWB 3.0L NW USA
1995 NJ GLX 5Spd SWB 3.0L SE QLD
1995 NJ GLX 5Spd SWB 3.0L SE QLD
I've just put a 2 1/4" system on my 3.0lt 5 speed as well. Headers and engine pipe are standard up to the cat, but the cat was replaced with a steel high flow and 2 1/4" to the muffler and 2 1/2" from muffler back. I feel it made a great difference to the low down torque and up top HP. I havn't had mine dyno tuned so i can't display figures, however i know my car well and it definitely made a difference. Apparently, extractors add a bit more as well.
Hi I'm in the market for almost the same thing, except mine's an Auto. You mentioned that the cat was replaced: are we allowed to do this???!! My car's 1992, so by now the cat should be shot and I've no qualms throwing it out, so that there's less restrictions. Only concern's the EPA regulations on cats. I'm in Mulgrave, can you tell me which shop you went to for the exhaust job? Thanks for your help.hudson44 wrote:I've just put a 2 1/4" system on my 3.0lt 5 speed as well. Headers and engine pipe are standard up to the cat, but the cat was replaced with a steel high flow and 2 1/4" to the muffler and 2 1/2" from muffler back. I feel it made a great difference to the low down torque and up top HP. I havn't had mine dyno tuned so i can't display figures, however i know my car well and it definitely made a difference. Apparently, extractors add a bit more as well.
'92 NH GLS LWB - Ironman Gas 2" Lift - ARB Bull Bar - Cooper S/Ts - Striker 170s...almost installed - more to come!
You are allowed to replace the CAT, you are not allowed to remove the internals or the CAT completely on a post 1987 vehicle. A high flow CAT has steel internals and apparently last forever, whereas a standard one has ceramic (?) internals. Had mine done in Coburg but any exhaust joint will be able to do the job.
Thanks - that clears things up.hudson44 wrote:You are allowed to replace the CAT, you are not allowed to remove the internals or the CAT completely on a post 1987 vehicle. A high flow CAT has steel internals and apparently last forever, whereas a standard one has ceramic (?) internals. Had mine done in Coburg but any exhaust joint will be able to do the job.
'92 NH GLS LWB - Ironman Gas 2" Lift - ARB Bull Bar - Cooper S/Ts - Striker 170s...almost installed - more to come!
Yes with mine he replaced the leads with Magnecore 8.5mm units as the stock ones had seen better days and new plugs. He made sure there was a nice fat spark.
Replaced the air filter with a Ryco (he found that it gave better results than the Finer Filter).
It already had a Airtek snorkel.
This bloke is a EFI/turbo specialist that does a lot of performance mods and tuning.
From memory he said the new exhaust system/extactors were worth about half the increase (7-8Kw).
He didn't touch the ECU but advanced the timing and adjusted the TPS that I distinctly remember. Unfortunately I was really busy that day at work and really never got a chance to discuss exactly everything he did but did see the final dyno run when I picked it up.
I do remember him saying that a lot of vehicles are set conservatively from the factory and 10-15% power increase is easily available if you know what your doing and have the equipment. I remember him saying that it is pretty similar to what a ECU chip does anyway and they are generally a rip off. He said he could have got even more power but all top end and it would have robbed the bottom end.
As I said I was VERY happy with the results and the Paj went noticeably better than before.
I have an article in a old 4x4 mag about a 3.0V6 NH Paj auto having a Genie system plus 2.25" exhaust and high flow muffler fitted (original cat used) and this yielded a 6Kw increase on the dyno at the rear wheels. I do know that Genie improved the Paj headers just before I had mine fitted which were supposed to flow more so this ties in with what the EFI guy told me about the exhaust only mods power imcrease.
Replaced the air filter with a Ryco (he found that it gave better results than the Finer Filter).
It already had a Airtek snorkel.
This bloke is a EFI/turbo specialist that does a lot of performance mods and tuning.
From memory he said the new exhaust system/extactors were worth about half the increase (7-8Kw).
He didn't touch the ECU but advanced the timing and adjusted the TPS that I distinctly remember. Unfortunately I was really busy that day at work and really never got a chance to discuss exactly everything he did but did see the final dyno run when I picked it up.
I do remember him saying that a lot of vehicles are set conservatively from the factory and 10-15% power increase is easily available if you know what your doing and have the equipment. I remember him saying that it is pretty similar to what a ECU chip does anyway and they are generally a rip off. He said he could have got even more power but all top end and it would have robbed the bottom end.
As I said I was VERY happy with the results and the Paj went noticeably better than before.
I have an article in a old 4x4 mag about a 3.0V6 NH Paj auto having a Genie system plus 2.25" exhaust and high flow muffler fitted (original cat used) and this yielded a 6Kw increase on the dyno at the rear wheels. I do know that Genie improved the Paj headers just before I had mine fitted which were supposed to flow more so this ties in with what the EFI guy told me about the exhaust only mods power imcrease.
I just luv my "clacker Jabber"
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