Cory74700 Posted January 23, 2013 Share Posted January 23, 2013 I've been doing some research on the headers available for this motor through various companies, and I don't like the fact that it requires the cutting away from some of the frame to instal them. So I've come to the conclusion that I will be making my own set of bolt on headers specific to the vg30imotor in the pathfinder. I will then either be chroming them or ceramic coating them, does this sound like a good idea or bad?? I can get all the necessary pieces, I have plenty of welding experience, and ceramic coating is fairly simple as well. If I were to be able to successfully able to make these continuously would it be possible to have a short term market for them?? Thanks. Link to comment Share on other sites More sharing options...
Trogdor636 Posted January 23, 2013 Share Posted January 23, 2013 Which headers require you to cut your frame? Link to comment Share on other sites More sharing options...
Tungsten Posted January 23, 2013 Share Posted January 23, 2013 Yeah I wonder too... None of the headers I know of will require cutting the frame. The exhaust system after the Y-pipe may sometimes require some trimming of the left transmission cross-member mount. No big deal there. The only time it is probably needed to have to trim the frame if you are doing something like a turbo installation. Link to comment Share on other sites More sharing options...
MY1PATH Posted January 23, 2013 Share Posted January 23, 2013 I've seen thorley long and short tubes, I've seen pace setters and I've seen Mr510's headers (very nice) and none of them required any frame modification. Link to comment Share on other sites More sharing options...
adamzan Posted January 23, 2013 Share Posted January 23, 2013 Maybe you should research here from people who've actually installed them on these vehicles... Link to comment Share on other sites More sharing options...
Kingman Posted January 23, 2013 Share Posted January 23, 2013 I've installed a set of Pacesetters and Mr.510s and neither require any frame modification. The Pacesetters however, on the passenger side, come really close (about 1/4-3/8") to the fuel lines and vent tubes so heat shielding those is pretty much necessary. I will never buy another set of headers other than Mr.510's because they were designed by a professional in the 510 racing industry, their hand made build quality is through the roof, and well he's a good guy and a good friend so I'd rather my hard earned money go to him. 2 Link to comment Share on other sites More sharing options...
Tungsten Posted January 23, 2013 Share Posted January 23, 2013 Agreed on using Mr.510s headers. The only problem with those is they do not pass smog. I know that he does not stock or inventory them so they are made as soon as he gets an order. Maybe he can put a bung in them for the EGR valve and then they will be street legal? Mr.510s headers are absolutely the best headers you can buy for your Nissan. The second best I would say are Doug Thorley units. They are smog legal too. Link to comment Share on other sites More sharing options...
Cory74700 Posted January 23, 2013 Author Share Posted January 23, 2013 I'm not sure which brand it was but it said right on the page that they were meant for a d21 hardbody pickup which has dma different frame and crossmember and my bad it was the cross member not the frame that gets cut I would still enjoy making my own set of headers for dirt cheap and ceramic coating them myself and doing the whole deal for under $100 rather than paying in excess of $450-$500 for a pair from some company that can't even ceramic coat the inside. And I've seen Mr510 headers, the outlet has the same connector as stock making it less universal for a true dual exhaust which is what I'm aiming for, coming off the headers to twin CA legal cats to dual glasspacks and on out, I'm more into uniqueness rather than stock, I mean how many people have a true dual exhaust on a pathfinder, and not coming off a Y pipe?? Sounds like a challenge to me, especially the ability to make it work with the IRS ill be doing, I love a challenge, unlike Chevy headers, those are straightforward to make Link to comment Share on other sites More sharing options...
Tungsten Posted January 23, 2013 Share Posted January 23, 2013 Alright well if you really want to make your own there are a few guides on how to select the correct size tube. I hope you have access to a CNC bender too. Also, true dual exhaust on a VG30 motor sucks. You want to at least go through an X pipe. If you really want a challenge try making equal length headers that dump into equal length downpipes then go through an X pipe. Link to comment Share on other sites More sharing options...
Trogdor636 Posted January 23, 2013 Share Posted January 23, 2013 Nobody has a true dual exhaust because it doesn't work very well. Link to comment Share on other sites More sharing options...
Slartibartfast Posted January 23, 2013 Share Posted January 23, 2013 If you want to 'roll your own' without going through all the bending and measuring and whatnot you might try what Nissan Nut did and hack a cheap set of 300ZX headers to fit. And yeah, from what I've heard the VG30 firing order is all wrong to run true duals. Link to comment Share on other sites More sharing options...
Cory74700 Posted January 23, 2013 Author Share Posted January 23, 2013 Hmm ill consider that x pipe idea it may be easier that way and still keep the back pressure correct but the firing order being wrong sounds obsurd due to the fact that right when I got the pathfinder it didn't have an exhaust period it stopped after the exhaust manifolds and ran like a top, no misfiring or odd sounds just sounded like a mean v6 of course it was completely illegal to drive that way until I got the exhaust pipes ordered and installed from nissan but nothing sounded or performed incorrectly Link to comment Share on other sites More sharing options...
Tungsten Posted January 24, 2013 Share Posted January 24, 2013 Actually in an exhaust you want to have zero back pressure. The firing order is 1-2-3-4-5-6. The system relies on a cross over pipe for scavenging. The firing from the left bank will scavenge the exhaust from the right bank and vice versa. Link to comment Share on other sites More sharing options...
Cory74700 Posted January 24, 2013 Author Share Posted January 24, 2013 A lot of cars come with tons of back pressure due to the exhaust, ie, catalytic converter, stock mufflers, single exhaust, that's partially how you get such high compression not nearly as much as high compression pistons, upgraded cam, lifters, rods and such but it does play a part in obtaining more compression but I don't need hardly any for the application ill be having it for. I just off-road a lot I don't need balls to the walls power I want to get the job done and still have my vehicle sound good too, that's why I'm going with headers, high flow CA legal cats, and glass pack mufflers, which will result in very little back pressure but I like the idea of an X pipe I'm just curious as to wether ill have the clearance between my drive shaft and the body when ripping through ruts or whoops as I have a drive shaft from a mid 80s peterbuilt, its larger than stock, not by much but you never know what will happen. 1 Link to comment Share on other sites More sharing options...
MY1PATH Posted January 24, 2013 Share Posted January 24, 2013 (edited) Agreed on using Mr.510s headers. The only problem with those is they do not pass smog. I know that he does not stock or inventory them so they are made as soon as he gets an order. Maybe he can put a bung in them for the EGR valve and then they will be street legal? Mr.510s headers are absolutely the best headers you can buy for your Nissan. The second best I would say are Doug Thorley units. They are smog legal too. MR510's headders will pass emissions tests depeding on the standards and He will Add EGR per request making them pass and emisson test the stock setup could. They will not pass visual component inspection it the headers get questioned because a MFR must pay tens of thousands of dollars to get them added to an EPA or CARB list. So, For smog, the only difference between his and thorley is that he cannot affort to pay for the approval rating. Edited January 24, 2013 by MY1PATH 1 Link to comment Share on other sites More sharing options...
Tungsten Posted January 24, 2013 Share Posted January 24, 2013 A lot of cars come with tons of back pressure due to the exhaust, ie, catalytic converter, stock mufflers, single exhaust, that's partially how you get such high compression not nearly as much as high compression pistons, upgraded cam, lifters, rods and such but it does play a part in obtaining more compression but I don't need hardly any for the application ill be having it for. I just off-road a lot I don't need balls to the walls power I want to get the job done and still have my vehicle sound good too, that's why I'm going with headers, high flow CA legal cats, and glass pack mufflers, which will result in very little back pressure but I like the idea of an X pipe I'm just curious as to wether ill have the clearance between my drive shaft and the body when ripping through ruts or whoops as I have a drive shaft from a mid 80s peterbuilt, its larger than stock, not by much but you never know what will happen. No, back pressure is bad. All that OEM junk only reduces horsepower and exhaust flow. OEM is made for optimal flow at low rpms. You want optimal flow for your target RPM range and not back pressure. Link to comment Share on other sites More sharing options...
Cory74700 Posted January 24, 2013 Author Share Posted January 24, 2013 I don't know what all that optimal flow at low rpms means, I have stock exhaust stock everything except an ecu chip and my vg30i can safely hit and hold 8,000 rpms for a short period of time, I drive regularly anywhere between 3,250 and 4,000rpms and sip fuel at just under 32mpg at 188-190 Ho that whole low rpm optimal flow thing doesn't make sense to me. Link to comment Share on other sites More sharing options...
Tungsten Posted January 24, 2013 Share Posted January 24, 2013 That has to do more with the head design too. Stock VG30 heads are very restrictive for more low end power. Hence they produce optimal flow for low rpm operation. The only issue with the factory exhaust is that it is a little bit more restrictive than the heads. For low rpm operation this is not noticeable. You will however notice a small difference with an aftermarket exhaust during acceleration. In N/A form you do not make any power after about 5500 rpm and the torque peaks at about 3800 rpm. It's pointless to rev up to 8000 rpm. In fact at that engine speed, the lifters will float and the lubrication system no longer works properly. The red line is there for a reason. Also, I don't know how you are measuring but 32 mpg is impossible unless you are running dangerously lean. Link to comment Share on other sites More sharing options...
Cory74700 Posted January 24, 2013 Author Share Posted January 24, 2013 I have no redline on my tach, but I have noticed at about 5500rpms a slight decline in hp but after going up an additional 1500 rpms to 7,000 it gives a nice kick of power although I do not reccommend testing this under any circumstances to anyone who thinks about trying this, you risk the chance of severely ruining your engine, I knew the risk but persisted with it just for test purposes, and for my specific engine (not saying all vg30i engines are capable) it was more than capable of those rpms with no changes in my daily driving performance, to this day I've only hit that high maybe a handful of times and I'm not doing it again until I fully rebuild the motor, and tranny as I have just under 317,000 miles on it and the fuel economy isn't that far fetched if your not hammering on the gas, ease into shifts and keep a steady rpm while maintaining your engine, and engine friction points regularly ie. Transmission, rear and front differentials, wheel bearings, make sure tires have correct psi, no brakes sticking, pretty much removing road friction from the picture you can easily get 30-32mpg from this vehicle, as odd as it seems and as much as you'll disagree, these vehicles are quite aerodynamic for being as boxy as they are, that was another thing I did was stuck it in a wind tunnel to test the aerodynamics of it and it proved over 75% meaning that 75% of the air that contacted the car went right over, under, or to the side with minimal restriction the less than 15% was due to the mirrors, hood/grille/bumper assembly, and of course the tires. Keep in mind I have no roof rack, no spare tire rack, just body. During the fuel testing the lowest I got was 19mpg and that was full throttle, balls to the walls, intake wide open, pretty much maxing my 188hp almost 200 lb-ft of torque for a mile. But just standard driving easing up the rpms, shifting at 3,500 then cruising around the track I started at 24.5 then it eased its way up to the max of 32.4 then went down to 30.2 and bounced from that to 31.4 and held it consistent for the whole of 5miles, of course this isn't realistic when actually driving going uphill downhill turning sharply, inconsistent rpms, shifting. But on a flat track cruising at 2,600 rpms, 5th gear at 75mph I was averaging 30-31 mpg at a constant rate. Link to comment Share on other sites More sharing options...
ORCGuide Posted January 24, 2013 Share Posted January 24, 2013 I have no idea where you are getting your mileage numbers from. But I suspect your methodology is flawed. Start with a full tank of gas. Zero your trip odometer. Drive. City, highway, to the 7-11 and back home, whatever. . . Fill your tank at some point and divide the number of miles traveled by the number of gallons of gas that it took to refill your tank. That puts you on a level playing field with everyone else here. I'm sure my pathfinder gets close to 40mpg going down a steep hill with a stiff tailwind. Unfortunately its probably closer to 15 MPG going up that same hill. Fuel economy is a long term average. Summer/Winter, City (stop and go)/Highway, elevation, it's all relevant. For example: My wife's Saturn ('99 SW1, fuel injected 1.9L SOHC, autotragic) gets a pretty consistent 35 MPG commuting to work during the summer (combined city and highway). In Winter, it drops to around 30 MPG. Last summer we took a road trip to the wet coast and got 42 MPG. My 1980 Celica GT (2.0 liters of terror, four cylinders of Fury! 5 speed, really tall gears. . .) used to get 20-25 MPG around town depending on the season. On one particularly memorable road trip it managed an astounding 29 MPG on one tank of gas. The astounding part was I ran that section of twisty mountain road at wide open throttle in second and third gear. . . something about peak volumetric efficiency 'er whatever. . . Link to comment Share on other sites More sharing options...
MY1PATH Posted January 24, 2013 Share Posted January 24, 2013 (edited) oh boy... well for starters, healthy vg series engines can rev freely to 8k without risk of damage. Our local VG expert (builds VG-510's for a living) has done it many times on stock valve springs. Not much point to it tho, even fully worked over VG heads run out of breath around 7k Now tach or no tach, No stock nissan ECU lets you go past 6.6k and most of them are 6k or 6.2k most MPG I ever got in my pathy is 23 and my wifes frequently hits the 20 and 21 mark. Most MPG I ever got with a VG30 is 27 and that was my Infiniti M30 doing the drive from Salem, OR to Seattle, WA Edited January 24, 2013 by MY1PATH Link to comment Share on other sites More sharing options...
Cory74700 Posted January 24, 2013 Author Share Posted January 24, 2013 670 and 7 tenths of a mile on a full tank was my average last summer my lowest was 540 and 3 tenths highest was 706 and 2 tenths, keep in mind that was solely freeway on a trip to Idaho, the low was a combo of highway and city on the way to Aspen Colorado driving around town here to and from work and the occasional 4 wheeling trip gets me an average of around 590-620 on a full tank if I'm solely 4wheeling my lowest was 437 and 5 tenths, taking it in and out of 4 wheel drive keep in mind I have a 22 us gal tank and a low flow pump and by freeway I mean my speeds were 70-75 the whole trip and city is varying speeds for me between 15 and 40 Link to comment Share on other sites More sharing options...
Cory74700 Posted January 24, 2013 Author Share Posted January 24, 2013 Also my1path keep in mind I do have a modified ecu so the stock part of the ecu doesn't apply to me Link to comment Share on other sites More sharing options...
Cory74700 Posted January 24, 2013 Author Share Posted January 24, 2013 Fuel mileage was tested by a computer rigged to my engine measuring fuel flow through the lines, rpms, and air flow, the tech set it up then told me it calculates through some equation that I didn't understand, then he got in and told me how to drive how I normally do which fetched average results of 20.6 mpg city, 28.4mpg highway, then we changed up the way I drive and went from speeds as low as 55 up to 80 which is what the computer is set to max at, the optimal was at 75mph 2,600rpms 5th gear then we moved tracks and set up for city driving stopping and going from speeds not exceeding 35mph but no lower than 15mph the lowest was 20mph at 2,500 rpms 1st gear of 17.3mpg high of 25.8 at 30mph 2nd gear at 2,100rpms Link to comment Share on other sites More sharing options...
krmiller07 Posted January 25, 2013 Share Posted January 25, 2013 Who or where did you get this 'flashed' ECU EPROM? Link to comment Share on other sites More sharing options...
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