89fbrestor

i did a 3.8 fiero years ago and posted a thread in the fiero forum about "whats the science behind a good set of headers" and based off that thread (which ended up having amazing info from some really smart car guys and over 600 replies) i had an awesome set of headers made up that performed better then expected.... cost me a small fortune but well worth it lol well now i'm doing this turbo build and just curious if the same applies? scavenging, back pressure, flow/equal length, diameter of tubes etc.

after looking at the headers offered on ebay for turbo's i don't like either set up, the ones that come straight up or the ones that put it low and in front of the motor. so my plan is to build my own BUT is there a science behind a turbo header set up? is there things to consider other then just dumping the exhaust into the turbo? I'm doing a single turbo build, so do i need both exhaust to power the turbo or just one... etc. please chime in guys this would be some great info i know id like to have in my library... well unless theirs nothing to it and its just "dump em into the turbo" lol

thanks
Brian

PS, i would have put this in the exhaust forum but this is specifically for a power adder so i thought this would be better here if not... sorry.

project89

iTrader: (1)

as long as it dont look like this ur good to go

J91

Oh my, not good....

Orr89RocZ

iTrader: (20)

There is science to header design but for a turbo V8 street car, you dont have to get to fancy to make half decent power. There are simple log manifold setups that make over 600whp and some even more.

Basically if you can do something like this:


You will be well off.

You dont have to get too big on the primary tube size. A good 2.5" collector, merging into a single T4 or T6 flange, depending on the turbo size you get, will be more than enough to make huge power.

The key is, if the turbo is heavy, dont use the headers to support the weight. Make a turbo brace. If you want it to last a longer time without warping due to extreme heat, use thicker materials like schedule 10 or 40 weld els and a good thick header flange 1/2" thick. Now I used regular hooker header flanges and mild steel 16ga pipe to make mine and support each turbo weight by itself but the design is very rigid and its working so far.

89fbrestor

thanks ore. simple enough. so it helps to have a good header but not necessary to get decent numbers for turbo.

project89.... don't be silly those will clean up just fine with a little grinding.... cutting.. and dynamite lolol

89fbrestor

well just a little fyi i posted this question in the turbo forum and had a few chime in and one guy gave this link http://www.enginebasics.com/ and it has some good info on turbo headers if anyone wants to read up on it. iv decided to go with professionally made headers instead of making my own. talked to 10secgal on that site as well and he has some really really nice headers but they come at a $700 price tag. price isn't' that bad but for some on a budget I'm sure that's a little high. but it give you some ideas.

Orr89RocZ

iTrader: (20)

Great link! You can get very technical with exhaust design but for the most part, keep it simple stupid.... log manifolds work well enough to mediocre hp levels, so if you are not looking for big HP numbers, just make a simple log design.

89fbrestor

"keep it simple stupid" ore were you calling me stupid ? i hope not, i just thought it would be some good knowledge to have for myself and anyone interested. hopfully i just misunderstood. agreed on the level you want to put into a set of headers. you get what you pay for. for me I'm using a gm block and i don't have plans of making the big #'s like ore or some of the other on here. id be happy with 550hp. I'm buying my turbo tomorrow so i'll be starting my build any day now and we'll see.

thanks for chiming in again ore... even if you did call me stupid.. i still respect you and your knowledge lol

Orr89RocZ

iTrader: (20)

No no, the saying KISS stands for keep it simple stupid. It refers to anyone doing something and reminds you that you shouldnt complicate things.

It boils down to how much you have to spend and what your power goals are. 10 second goal's headers are NICE and for 600-700 bucks, they really arent a bad deal since you can have 500 bucks in materials/welding hrs into making them yourself. They are nice headers for just about any hp goal you have in mind

However, if you only need to make 450-500whp, they are alittle overkill. You can make a 200 dollar log setup and make 500 hp. Like stock internal L98 that you just want to add 7-10psi too, those headers are alittle much. A simpler BBS type setup would work somewhat ok and be cheaper if you made it yourself.

Thats all I am saying. Great link with great information to follow on any build but you can get away with less.

89fbrestor

lol gotcha and ya agreed. i talked to 10secgal over there as well and very nice guy and sounds like he'd be great to deal with. he has a LOT of respect on the turbo forum for anyone interested.

for my build i wont be using stock internals i plan on doing all forged. I'm honestly hoping for the 550hp on turbo plus id like to use a 75 to 100hp shot of nitrous as iv been reading some good stuff about helping to spool for launches. i'm going with the gt45 turbo, victor jr intake and blow through carb.

Orr89RocZ

iTrader: (20)

https://www.thirdgen.org/forums/ltx-...lq4-build.html

Check this thread. great example of a budget log build that will make big power numbers.

89fbrestor

now thats pretty simple. i'm still not unsure if i want to go twin or single turbo. i just ordered all my suspension stuff today from umi next is get my motor ready i think i'll wait till last to buy the turbo and decide then if i want twin or single. my hp goals are only 600hp and i think that would be relatively easy to do with a single gt45. thanks for the link.

if i do twin i think i'm going to do block huggers and bring them under the motor between the oil pan and the motor mount and back up to the front of the motor. theres a guy over at the turbo forum who did that and wow does it look clean.

brian

83 Crossfire TA

iTrader: (2)

there are a ton of variables, but the short version is that the bigger the turbo setup gets, the closer to a race setup it is and the less you care about low end response the closer things get to the optimum NA setup.

OTOH, start forgetting about all that and most people will be surprised that the best setup is usually not large, and doesn't have to be a tubular header. Your 2 biggest concerns in turbo headers is preventing reversion and retaining heat, and in most cases a well designed log is better than a "header."

You don't really need much crossectional area, there are single turbo setups making over 1000hp running all the exhaust through a 2-2.5" section. Some will argue that you'll start seeing a restriction with them on higher powered setups, but what is really happening is that they are retaining more heat and getting more energy to the turbine so the turbine actually becomes the restriction. Putting tubular headers on it can fix this but it is not because the log was a restriction, but because you're actually getting less of the exhaust energy to the turbo. a better, more efficient setup is to actually run a larger turbine side.

project89

iTrader: (1)

do a single setup theres alot less plumbing involved, so difficulty of plumbing is kept to a minimum and all the stuff u will need for oil feeds and drians will add up in a hurry as well with a twin setup.

just be awar if u decide to go with a t6 large frame turbo that is just as hard to firt in the engine bay as twins. mid frame turbos are pretty easy

89fbrestor

83, GREAT info thank you for chiming in. comes down to you get what you pay for from what I'm reading. my thing right now is the location of the turbos i have a position I'm looking for and it seems any prefabbed ones either have them to high or to low. kind why I'm thinking on doing my own. I'm a programmer and i think its made me over the years care to much about details lol i want symmetry to be spot on and the look to be exactly what i see in my head not to high or low but have good flow and try to stay with the basic principles of a good header design.

really thinking block huggers which will give me DECENT,equal flow out of the head(if I'm explaining that right) to the turbo then true duals to the back. not sure if id need to use an X or H pipe yet. anyway that where I'm at right now.

PROJECT89 well my thinking with single vs twin is size. i would need something pretty big to get the hp I'm looking for and i think 1 turbo is going to look pretty bulky in that engine bay... kinda leaning toward to gt35's now. i sold the single turbo i had (to small) so i still have time to decide. right now I'm stripping the car and redoing the underbody and suspension.

thanks guys
brian

83 Crossfire TA

iTrader: (2)

I haven't seen a set of block huggers that will put them where you want them, typically right side up the motor mounts get in the way of any kind of useful plumbing, and upside down they end up too high. The C4 vette block huggers are about as compact as they come and I posted pics of them upside down with the collectors cut down and a pair of T3's on them and they end up sitting very high, I could get them under the hood but I didn't like it.

you don't need an H or X at all

89fbrestor

well i haven't started this part of the build yet but the link below is what I'm wanting to do. I'd recommend going through this guys build...... amazing build and it looks sweet. if i cant do it this way then so be it but if i can manage then I'll be a happy camper. i was thinking about buying the tube k-member so i could get some more room under the motor or notching the stock member and reinforcing it so i could fit the plumbing there.

http://www.forabodiesonly.com/mopar/...=1#post1087719