wolffman007

iTrader: (1)

first off i just started looking into turbos
and yes i know all to well about the serach function & am using it, as you all know there are 1000's of posts regarding turbos & am reading them, but so far i havent come across this idea yet
i dont have any of the books about turbo's yet & im sure they will answer some of other questions i have
i have a couple of questions about making my own manifolds

from what ive read so far stainless is better in the long rung than mild steel, id probalby use mild steel to make a prototype first

i think its lil quick pic of his engine with the gale banks manilfolds that inspired my idea & im needing to know from you more experienced folks if its feasible, if not why or what needs to change to make it so or if it just wont plain work

attaching said pic to help illustrate

now why couldnt you take say a 2 1/2 in or maybe 2 in square tube & use that as the manilfold itself, with the exhaust ports cut out & drilled for the bolts, im sure there would be leakage from the outside where the bolt would go up against the tube manifold, so i thought what about drilling the hole larger & then feeding in a "round sleeve" into the enlarged drilled out section & welding that in, so theres no leak, granted it would restrict the airflow some, but is that a problem?

then seal off the back & for the front weld on an adapter or flange for the wastegate like in the pic & then mount the turbo on top provided theres clearance or they could maybe be mounted at the front of the manifolds instead of the wastegate

ive also read on here that someone used a gravity feed return oil line into the valve cover, is that a good option or not?

thanxs, Shawn

Raven90IROC

Personally I like the BBS designs much better. Im sure theres a tonne of technical reasons why, but i just think they look cooler.

BBS is also the kits that uses the gravity fed system into the R-cover. It works fine as long as the turbo(s) end up over the covers. Both mine, and the one you posted are too far over to the side for that method to work really well. General opinion is that your better off draining into the sump anyway.

Is it just me, or are the wastegate holes on those headers to posted bloody tiny?

dankhound

Itd be much easer and efficient to modify an existing header than building one completly from scratch.

wolffman007

iTrader: (1)

easier maybe, except i work in a metal fabricating shop, so i have lots of tools available

efficient? thats what im needing to know, how would an existing header be more efficient?, as a 2 1/2 inch pipe has an ID of 2 inches, thats more than most headers

RedLineByrd

I'm thinking the log type manifolds would be very ineffiecent at scavaging, though I am no expert. Also, getting the exhaust to flow one direction may take a bit of persuading, which would hurt thr flow. Less flow = more lag(unless a smaller impeller is used) and it would all add up to less power then if you made or bought a header type of set up. That is just my opinion though, and I am no expert.

The_Raven

The design you propose, being a square tube attached to the exhaust ports, is inefficiant at best, gasses don't flow well through a square hole well at at all. As mentioned Scavenging will be poor, and so will velocity because of this.

Best flowing will be a tubular header, or similar, having at least a couple inches of "runner" from the port to a comon "chamber" for all cylinders, this will also help with antireversion.

On top of just a poor manifold design, you also would not have access to the spark plugs, or not easy anyway, you'd have to place notches on the main log for the spark plugs, and another for the temp sensor.

Do yourself a favour and build some header type manifolds or modify an existing set.

83 Crossfire TA

iTrader: (2)

Don’t worry about the nay-sayers… It can work. No, square is not the most efficient shape for flow, generally the corners end up wasted space, but it can be made to work and even used for flow control (look at all the rectangular port heads out there). Done right it will be better at lower rpm conditions and not as good at high rpm conditions, it will spool faster but also run out of breath faster assuming the same turbine size. Just size the turbine slightly larger then you would with a tubular header type deal.

The place that you’re going to have issues with this is keeping it sealed to the head. You’ll be fighting 2 things here: expansion rates and keeping the flange surface flat. I haven’t played with this to know for sure, but I suspect the way to deal with the flage deal is to actually weld a ¼” or so flange to the inside side of the square tubing to carry the load. Yes, it will be a hassle to weld without getting it twisted (I’d shoot for getting as much of it welded as you can bolted to a head or a heavy steel plate, and then you still might have to get it surfaced when you’re done). The expansion… well, I don’t really have a great answer besides trying something like ford did on it’s big block exhaust manifolds, make the center bolt holes bolt size, and let them get progressively larger as you get towards the ends of the heads and use big/heavy washers under the bolts or nuts if you use studs. That will allow for some motion without warping. You might want to look at what some of the mopar slant 6 guys are doing to keep their manifolds sealed since they’re fighting some of the longest manifold assemblies out there. A friend of mine swears by high temp, copper ANTI SIEZE on the gaskets and all the fasteners to give it something that will not burn out but will allow the surfaces to slide relative to each other.

FWIW, there used to be a guy on one of the jy turbo boards or forums that did exactly this on a small block mopar in a newish Dakota. I seem to remember that the stock drivetrain with a manifold like this and a smallish T4 was running consistent low 12’s or high 11’s when the guy dropped off the radar…

83 Crossfire TA

iTrader: (2)

Here's a pic of the parts

Mike-91 Formula 350

They would be if the setup was not going to be used with a turbo.Once the turbo is on there is no such thing as scavenging since the turbo becomes a restriction.Instead of mild tubing I have seen a lot of people buying weld els at the plumbing supply and running them into the logs.

The_Raven

Say what? Using that logic, as soon as a muffler is placed in teh exhaust scavenging is also moot.

Nope, Scavenging, regardles of aspiration is essential.

83 Crossfire TA

iTrader: (2)

A properly designed exhaust system should have <3psi backpressure, if you follow what Vizard and a few others suggest, it should be sized and designed for no backpressure.

With a turbo setup you’re typically seeing 1.5-2.5x the intake boost pressure in the exhaust and you totally change the equation. You are not going to have a quick spooling turbo and get rid of that (you can lower it significantly by decreasing back pressure after the turbine, but once you do that you’ll have roughly the same backpressure at the port with similar spooling characteristics, as a matter of fact, I would argue that if you were going to try to control that you’d have better success with a properly designed manifold then a header…). Because of this you really will not/can not have exhaust system scavenging like you would on in a NA application. By messing with port profile and pressure/flow diodes (fluidics) you might be able to actually get scavenging at the exhaust valve, but not really from the exhaust, and that would involve smaller ports then most people run and something more manifold like for the exhaust structure.

89JYturbo

Here is an even easier way to build reliable turbo manifolds. You can even add WG port to the front of them like the Banks manifolds shown above (I didn't because I have internal gates). The overall layout is similar to the Banks design, the benefit being you can build them to fit our cars better (without cuting the under-hood structure for clearance).

junkcltr

iTrader: (1)

89JYturbo,
How are those manifolds holding up? How many miles on them? Do you run S/S flex pipes or bolt solid to the exhaust?
I have an extra set of manifolds kicking around that I want to use on the pick-up truck. I think I the best setup for it is to make boxes for them almost exactly like you have. Since it is getting to cold now I don't think doing the nickel firepit thing would be worth it so I might try using the MIG on them. So I am curious about how they are doing.

Thanks,
J

89JYturbo

My manifolds have about 10k miles on them, and have given me no problems. I drove it three hours straight from my home to the Wildwood NJ car cruise this September, and then another three hours straight on the return trip. My turbo system is three years old now.

FSTFBDY

iTrader: (33)

hows my ceramic looking?

83 Crossfire TA

iTrader: (2)

done correctly, there is no good reaso for those not to hold up, I would expect them to be more durable overall then most tubular headers.

I've done a set of welded up cast manifolds for a really tight engine swap in a friend's car and they've been in the car for 2 or 3 years now with no cracking or other issues (the originals were cracked, and it was a bit of work to fix the cracks and then move the outlets... the parts added were mostly cast elbows, but in a couple of cases I had to use some plain steel because I had to bend part of it in a shape that I couldn't get out of any of the cast pieces that I had around. I also used steel flanges on the oultlets).

89JYturbo

It's doing great. I'm so glad I had you do that, because the header paint I used on them the first time started to show rust through after about a year. I think your coating is over a year and a half old now, and looks like low sheen polished aluminum.

Next time, I want to get my turbine housings done as well.

FSTFBDY

iTrader: (33)

awesome. I like to hear good feedback like that. Esp in a Turbo setup after as many miles as you have put on it.

83 Crossfire TA

iTrader: (2)

did you end up using normal header coating or a high temp turbo coating of sorts?

FSTFBDY

iTrader: (33)

Those are my regular silver for everything from Tech line


http://www.techlinecoatings.com/BulkExhaust.htm

TECH LINE coatings designed for exhaust systems, can handle base metal temperatures in excess of 2000f.

I also use Turbo X which is black.