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Engine Specific Info and Questions => IDI Engine => Topic started by: dubCanuck1 on March 20, 2006, 10:17:08 pm
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Ok, here's an addition to the "moderate" mods on a 1.6TD I posted last year.
I'm thinking 2.5" downpipe and back, including a free-flowing muffler.
Before I give 935Racer some more money for a downpipe, I wanted to exhaust the exhaust topic (ooo that's punny).
As a review, here's what the TD project will look like
FMIC
Governor mod (only partially solid, not completely)
More fuel
Way more boost
Engine pretty much rebuilt, likely with some coated bits
Gauges, gauges, gauges (I get 10 more hp each time I use the word "gauges" :D)
So my first question....how to calculate air flow through an intercooler and also how to calculate air flow through the exhaust. Is this a simple matter of determining the area of the opening or is there another factor involved?
I know if you go with a 3", you will need to plumb the exhaust under the rear axle (unless you like the bumpety noises).
If going with a 3" exhaust, what are potentially negative impacts on low end power, spool time, etc....
I'm taking my time on this and want to do it intelligently, so let's hear it guys.
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Hmmm. I did a little research and I guess it doesn't really matter with a TD what size your exhaust is over say 2.5" There doesn't seem to be any detrimental effects.
Confirmation/rejection?
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2-2.5" is perfect.
If you go bigger the airflow will slow down quickly (blocking the gasses behind it) and even backdraft could occur.
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2.5 inch from turbo back into free flowing magnaflow muffler with tdi style tip is what im doing. what is stock size by the way?
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2.5 is plenty. stock is under 2"
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I ran 3" for a long time, its a pain to plumb, you need a good patiant (sp?) fabricator, 2.5" is a lot easier and like everyone else says will flow plenty for what you are trying to achive, the only time I would start thinking bigger is for Malone, or Andy2, as there Big turbos, exducer is 3" or bigger and so there downpipe would be 3" too match, and you would want to continue that out back.
I never tested full 2.5" exahust but spool up and egt's on my car were no different running an open 2.5" downpipe as were running a full 3" exhaust including a dynomax bullet race muffler, and you could actually drive it for more then 15min, without getting a headache from the drone.
So to some up if you are going with a bigger turbo then the stock k24 / garrett conterpart, then I would concider a 3" all the way including dp. If not go with either 2.5" PP or 2.25" TT setups. Clear as mud?? :wink:
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The mud is clear.
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what kind of mud is clear?! geeez.
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Yeah, I better stay off the funny pills.
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If not go with either 2.5" PP or 2.25" TT setups.
I know TT is Techtonics. What's PP ?
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passenger performance out in BC
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passenger performance out in BC
Ah, yess, but I think they only make downpipes.
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Is anyone familiar with muffler bender program cards? I googled and see that Huth (aka Midas) still sells these. Basically the card tells you how to make a specific pipe for a car, ie cut pipe X inches long bend Y degrees at specified radius at Z inches from end, rotate pipe some degrees before next bend at ....etc. So you can start with a straight pipe, spend some time with the bender then walk up to the car with expectations that it will fit like factory.
More years ago than I like to recall I worked in a brake and muffler shop. First choice was to order pre-bent pipe for a job as it was cheaper that rolling our own. But if something wasnt available the program cards provided a good alternative. More to the point, we did lots of custom work, if we recorded what we did as we bent a custom pipe, we could come back months later and reproduce it, in just a few minutes. The factory program card was also a great starting point for building a custom system with larger pipe, usually by eyeball you could see where to slightly adjust lengths or radius to make a larger pipe fit...record the changes you made and next time was easy.
So if us diesel guys had a 'open source' program card for a 2.5" system, you could walk into any well equiped muffler shop and have the pipes bent cheaply. Even easily make it in say 3 pieces with slip joints so it could be boxed and shipped.
yes, the bends are not zero crush, but you dont loose much internal volume on a bend unless it is tight radius and a large bend. It doesnt look like a mk2 or mk3 has any particularly tight bends, I doubt you would see much difference in performance between a 2.5" mandrel bent system and a 2.5" die bent system. The mandrel exhaust guys like to say how you can loose up to 20% volume with die bends, so worst case die bent 2.5" would be like a best case mandrel bent 2.25".
Does this interest anyone? I dont have access to do this work anymore, but I will need an exhaust system soon, so I might be up for a cost share of developing this, within reason. Then I'll be knocking on PP's door for a downpipe!
An aside, Walker shows their factory replacement exhaust system for a 90-92 Jetta as a mix of 2" and 1.75" pipe.
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im deciding on weither or not to take my car to PP or get it done here at a local shop that does a really good job, he handles most of the "not so legal" parts of exhaust systems, does an awesome job.
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so turns out that shop can't do a 2.5 inch exhaust on a mk2 jetta cause he says not enough room between the floor and axle. So looks like im gonna be dealing with passenger performance this summer, woot! The shop cant even do mandrel bent, i say, "haha, amateur". Diesel already sounds nice stock, deep and loud.
http://youtube.com/watch?v=mKPgqvrt1Do
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most shops cant do mandrel. and many who can provide a mandrel exhaust fabricate it by cutting up individual bends to suit and welding it all together. i only know of one shop in my travels that actual has a mandrel bender and makes actual systems, but they deal in old muscle cars.
2.5" will fit fine, 3" is where you'll have trouble with the axle. either they don't realize that, or their work is sloppy and they need all the clearance they can get!! :lol:
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The car's height (suspension) should be taken into consideration. A 3" system didn't seem to rattle or rub at all on DVST8R's stock-height MK2 jetta, but it rattles like crazy on my lowered MK3 (about 2.75" down from stock height). The rear axle actually crushes the 3" pipe against the floor pan a bit. No clearance at all, unless the car lifts from going over bumps. This time I'm running just a downpipe.
TT sells over-the-axle 2.5" or 3.0" bends that clears a bit better. It seems popular in the gasser VW community. I'd probably consider that if I were to get a full 2.5" or 3.0" exhaust system again. I have a different exhaust plan that'll work well, though.
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60/40 drop is the ultimate goal.
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so turns out that shop can't do a 2.5 inch exhaust on a mk2 jetta cause he says not enough room between the floor and axle. So looks like im gonna be dealing with passenger performance this summer, woot! The shop cant even do mandrel bent, i say, "haha, amateur". Diesel already sounds nice stock, deep and loud.
http://youtube.com/watch?v=mKPgqvrt1Do
It can be done, I have a 2.5" from the DP back on mine, and it's got minimal crush on the bend over the axle... it was done by a "trucker shop" guy that really knows his diesels, he said when I brought it in "it'll be tight up in there, it might bang - are you sure you want that?" I said "yeah, and I got a muffler to go inline too"
he then kinda gives me this funny look and says "it isnt one of them fart cans is it?" so I motion for him to look in my trunk and he looks and sees my borla stainless turbo muffler :shock:
then goes
"alright, I'll see what I can do"
so yeah, 2.5" will fit over the rear axle... but ya gotta take care while on the bender to get it just right.
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Blacktietd, Where is this muffler shop you speak of? The one with the mandrel bender, my buick is getting a new system this summer. I am in mississauga.
Thanks
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grannat: been trying to think of the name of the place........ all i remember is i was meeting someone to buy parts from one time and i saw a guy come out of a shop with a big mandrel bent system for his camaro... i poked around a little and they said they do mandrel systems mostly for US muscle........ but i can't for the life of me remember where/when/name or anything, was many years ago.... i will try to think of it for you! :oops:
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you want manderal whatever bent,,,,,better off on fabbing up your own,,,not everyone has this luxury,but i jus hit summit on the way home,and shove my way up thru all the knuckle scraping domestic neanderthals,they dont pay me no mind, whats a vw...and the ricers are stupid, they are buyin light up washer nozzles and 15 inchsubs ,,,, step up to the counter and order em up!!!be sure to grab a stack of summit stickers on the way out the door,they r free,and start sticking them on everything,,,once ya got all the vinyl horsepower,,bust out the welder,and start building,,i basically mimicked all the stock routing,,heehee,,,,,,didnt mean to offend the domestic dudes,it just sounded good :roll: :roll:,,crimps arent good but if ya live in the sticks you may bestuck
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grannat: try calling canadian coach works in milton :)
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Also, a company called Dr. Gas www.drgas.com (although their website is down currently) have oval exhaust tubing, just getting a small U-bend to go over the axle would let you fit some big tube in there and not worry about the axle clearance.
Brendan
84 Scirocco 8v
00 Camaro L36 M49
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You can use a flat style tube to give you more room over the rear axle.
You could also run 3" back and split before the axle,and run dual 2" pipes over the axle,as there is lots of room side to side for the two pipes to fit.
You could also run a 3" right out in front of the left rear wheel,instead of going over axle.
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You could also run a 3" right out in front of the left rear wheel,instead of going over axle.
you know that was an option i was considering, just not to sure about how much of the diesel would stick tot he car as it does to my rear right now.
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You could also run a 3" right out in front of the left rear wheel,instead of going over axle.
you know that was an option i was considering, just not to sure about how much of the diesel would stick tot he car as it does to my rear right now.
If you have diesel stuck to your rear now,I think you should get that checked out.May cause a serious rash if left untreated. :P
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as in my rear end is lightly dusted in diesel, i plan on getting a TDI style tip soon so it doesn't do that anymore, but im also probably gonna be painting the car this summer.
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my 2.5 goes straight back,,and stops at the rear axle beam,,and has a turndown, no muffler,it helps keepsome soot off,,,also marks the driveway every time i start it,,,,seen someone else say when you have a turndown,and do a burnout,,you can leave 3 black stripes :P
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what is the exhaust tip diameter on a 1.6TD?
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You could also run a 3" right out in front of the left rear wheel,instead of going over axle.
Just wondering with this set-up what kind of fumes you get sitting at idle with the window open. I would think it would be quite bad but I could be wrong.
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i had a left side exit on my jetta,,only thing i got a little nervous about was ,,how hot is that left rear tire getting on my 8 hour trip to ny?? idunno i never blew it out,but the sidewall,and wheelwould get pretty hot to the touch,,,never checked w/ temp gun either,,,,,,,,but the tire/wheel was black all the time,,gettin a continuous diesel soot paint job :D ,,also i left it at the rear beam on my latest creation,,and eliminated a bend,,,,,,,,,,,,,,,,,i havent really even noticed the stink,in either car,siting at light etc,,,,,,,,,,,one thing that did smell horrible was on my tdi,i got crankcase vented to atmosphere,and with the rain tray cut out,,,,sitting at a light w/ the heater on,,i smelled the breather fumes,,nasty stuff,,,since then,,hose reroutes it to bottom of left rear of wheelwell
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Did the ahead of the rear wheel thing on my pickup, but it's a four door so the pipe's still well behind the doors. No problems, saves all the headaches of going ove the axle.
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try this in your truck,,,,run it out the back,,,and add a "cutout" that exits near the back of your door,,,i used to be able to lean out,w/door open,and uncork it :twisted: :twisted: :shock:
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what is the exhaust tip diameter on a 1.6TD?
Too small @ 1.75" stock
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I've got 2"
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im going 2.5 from passenger performance this summer, along with the winter diesel package thingy, hopefully they got one for the summer, but i doubt it'd be different. I think im gonna like going to Aldergrove this summer :D :D
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Yeah. I've got to get one for the TD project too, as you can probably tell with all the ***ing I've been doing on "Project 2"
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as you can probably tell with all the ***ing I've been doing on "Project 2"
:lol: :lol: :lol: yack yack yack :lol: :lol: :lol:
apparently on the little cruise i went on today, the guy with the 16V and a few mods said he had some hard times keeping up with me when we were passing people...That makes me feel like im not being left in the dust so easily, and the fact that i should keep working on my car so i can leave everyone in the dust (by dust you know i mean black sooty dust) :lol: