SurleyOne
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Posts posted by SurleyOne
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Thanks a lot this is a big help for me. Surleyone
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I dumped about $4000 into my truck over the time that I have owned it and after going through some head aches I hope the following post will make someones life easier.
After using Doug Thorley headers for about a half a year I would like to post my experience and suggestions on what to do when installing them.
First of all, if you are planning to install these, make sure you are happy with what they do to your power band. The regular exhaust manifolds seemed to have a slightly different power band but not that much different from the headers. So you might want to check with someone that already owns these to see if you want to put these on your truck.
Are your studs broken?
The factory exhaust manifold studs are small, only 8mm in diameter so if you have the original studs, they are prone to cracking or breaking. If your current studs are broken, get the 300ZX turbo studs. They are initially golden in appearance but turn white as they will get hot. If your studs aren't broken, they are probably the revised grade 8 studs, which are probably the same as the 300ZX turbo studs. I suggest using studs over bolts as they are much easier to work with and are designed to work properly with the expansion/contraction rates. Go to your nearest Nissan dealer and buy all the proper fasteners. It will be around $120 but it is worth the expense.
Now what is that all about extending the EGR tube?
There are two different sets of headers made by DT. One is the short tube variant other is the long tube variant. The short tube ones are for the VG30E application and have the EGR port in a different location than the VG30i. The EGR tube on the VG30E engine does not need to be modified, it will fit right in. However, if you want to use the short tube headers on the VG30i engine then you need to extend the EGR tube to match. I don't know where the fitting goes on the long tubes and if its made for VG30E or VG30i.
Long tubes vs Short tubes?
I would say go with short, they are easy to install and have pretty much identical flow of the long tube. I don't think the long tubes are in production anymore.
Nickel Chrome vs Ceramic?
If you don't care about the looks, go with the chrome coated ones. They are cheaper and are just as tough as the counterpart. What will happen is the primary tubes will turn dark blue but because there is a stream of air by the crossover pipe, that part will stay shiny for a while.
What about the Oil Filter Relocation Kit?
You do not need to install it, the oil filter can be changed easily without it. However, if you really do hate the filter in that location then you can get a kit and mount it happily next to the transmission somewhere. WARNING! Any damage to the hose or oil filter will leave you disabled and without an engine.
How do I connect the stupid slip fitting to make it leak proof?
So if you put these things together without anything, you will have an exhaust leak at the slip fitting. What you need to do is put some high temp silicone (preferably copper based) into the slip fitting before you slide the two pieces together. If you haven't done that then you can still wedge the silicone in on around the side. Then you put a 2.00" lap joint band clamp on the slip fitting. If you have a MIG welder and want more stability then put a small tack weld where it will be easy to cut it off in the future should you choose to take the system apart (disconnect the battery if you are welding). You can remove the black sealer from the band clamp as you won't need it. Torque that band clamp to specification which is around 50 to 60 ft lbs. Do not use a regular exhaust clamp as it just will not work (it will break). I advise to not weld the slip joint around completely because you will have to drop the torsion bars to take the crossover pipe out.
Why does the DT install manual says to use high temp silicone on the gaskets?
I was told by a professional mechanic (on the job for 15 years) that putting silicone on new gaskets is stupid so you don't have to do it.
You should check the torque on all the nuts after an initial drive because they sometimes tend to back off.
What the hell is that rattle?
When you put your headers together, you may hear a clunking sound from the front end. That is the exhaust pipe hitting the frame, but not where you might think. Yes the headers do run close to the frame but they will not touch. The part that actually does touch is that U-shaped bend thing around the left side of the transmission crossmember. Take a grinder and grind off about a half inch off the crossmember and the rattle will be gone. You should get rid of that rattle because it will trigger your knock sensor.
If you don't hear a knock but your truck still hesitates, it is most likely that the O2 sensor has failed from your modding. Go get a new one ($140 from dealer) and swap it in then reset the ECU by pulling out the negative battery terminal for a few minutes.
What to do next?
Ideally you want 2.25" piping all the way from the collector (Y-pipe) to the tailpipe but if you choose to, you can re-use the auto store 2.00" piping. The stock is around 1.8750" so you will still gain a little diameter. Buy (or fab) new pipes if yours are completely rusty. My tailpipe was rusty so I replaced it with a NAPA one. My midpipe was ok so I reused it.
What to do for Muffler/Cat?
Anything. You can do a Magnaflow cat in either 2.25" or 2.00" and a Flowmaster 60 muffler. Make sure your muffler isn't too loud because you will hate the highway drone. The Flowmaster 60 seemed to make a perfect sound for me. Keep in mind that Flowmaster is not the best and I only got it because I know it works and don't know much about mufflers. While you are there, be sure to check on your catalytic converter and make sure it isn't plugged.
When installing the muffler, make sure it fits or make it fit. If you are re-using the old midpipe and notice the crimp that was made from the old exhaust clamp and muffler, don't worry about it, it will work as a flow enhancer. If you are installing a tough metal performance muffler like a Flowmaster, do not use the regular clamp. In fact, when doing a performance exhaust system, forget about regular clamps. You can use a band clamp and silicone combo identical to the header crossover pipe slip fitting or you can weld or both.
If you hear banging by the gas tank, the tailpipe is probably not bent correctly. In my case, my Magnaflow catalytic converter expanded so much that it forced my tailpipe against the gas tank. After bending the tail pipe a little bit, that problem went away.
For a finishing touch:
Install a tip on the exhaust with an outlet diameter between 2.25" and 3.00". Not only does it look nice, it sounds good too. Get a stainless steel one because the chrome ones look like crap after a few weeks. Clamped or welded is up to you but I prefer a clamp one because they are easy to swap and clean.
So there you have it, I hope this helps someone with their sport exhaust system.
FYI:
If you do not wish to install headers, fix your exhaust manifold studs and throw out those heat shields, they are useless. Also, if you don't see any black spots on the engine from the exhaust manifolds, they are fine but dump those heat shields anyway as they might hurt the studs and cause an annoying rattle when they rust. Instructions on how to change studs can be found throughout the forum and here: http://www.nissanpathfinders.net/forum/index.php?showtopic=16196
Another FYI:
If you do mod the exhaust system, it is a good idea to install a transmission cooler as it will keep the transmission happy with your mods. Look elsewhere on this forum for instructions on that.
I'm too lazy and tired to format all this crap but please read it...
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My exhaust is about to fall off, and i know that there are several legal ramifications and some mechanical ones. I'm an old Chevy V8 guy & they will run just fine no matter what you put on even straight pipes which are deafening. I used to run Cherry bombs on my V8 Chevy's, but can i do this with a Nissan V6. Is there enough back pressur. By Cherry Bombs, I mean that when you pick up the muffler & look through it there are NO RESTRICTIONS OR BAFFLES WHAT SO EVER! You can see right through. The muffler is simply an expansion chamber usually filled with fiberglass insulation, which does a great job of muffling the sound unless you put your foot to the floor & then she gets REAL LOUD!! So can I use these on my V6 without causing any damage, like burning out the valves? Surleyone
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Hello All, I currently have 3 Pathfinders. An 89 now cut up into a strictly off-road Truggy, and 2 '95 4dr auto's. The Truggy is/was a 2 dr std. I have been an avid off-roader for 20+ yrs, I also own 2 Toyota's and used to have a full size 82 Chev 1 ton 4x4 with a Farmer 4 speed and a 454 engine, running an RV cam $ standard Rochester 4 barrel carb. I like them all but have found the Pathy to suit my purposes best right now. I am probably buying another this wknd, another 4dr auto, I don't know why, probably for parts or another project. My daily driver a black 95 4 dr is getting a bit rusty, although the frame has only one small hole, I am going to swich over to the other 95 which is in really great shape, NO RUST little kms, spent most of it's life in a garage, Never off-roaded. Thanks SurleyOne
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Hi there I'm a newbie to your site , but not to wheeling. I currently own 3 pathy's 1] an 89 2dr standard which has been converted to a "Truggy" the rear frame rotted off and we welded up a frame out of HD angle iron, so it just has 2 seats & a lopped off back end. Off-road only bin like this for 3 yrs, used daily as entertainment & to haul logs out of the bush at my daughters farm, just E of Peterborough 2] a 92 4 dr auto, again frame rotted off, awaiting transformation into a flatbed, off-road only suitable for hauling logs & other stuff at the farm. #3] a 95 4 dr auto, out of the States, solid frame, great body, my daily driver ,totally loaded down with tools as I am in the construction biz & never know which tool I will need next. Pics of all to follow. I am currently looking for a "Hardbody" pu to join the set, &/or anything else that I can get my hands on for CHEAP. I intend to have the ULTIMATE USED PARTS SOURCE for 1st, 2nd & 3rd Gen Pathy's We are on a 100+ acre farm so there is lots of space for "project" trucks Love the site Run it til it breaks!