sorry I have been MIA for a while my laptop crashed and I am at the point where I am pretty sure I need a new hard drive for it but I have the passenger side header finally positioned to be welded need to get a few mild steel elbows thow. If anyone has leads or contacts for these I could use it. I will get a pic when I load the digital camera driver to my wifes computer. as for the drivers side that #$%$%^ is a tighter space than the passenger side I almost said #$%%$# it but then when I was under the car (where the AC pump was looking up toward the header on the drivers side to my surprise there was a good deal of space. So I am now contemplating mounting that turbo where the AC was and seeing if I can get a custom weldup job don that will route the header at an angle down to it. Can't touch the exhaust yet because I am still waiting on a 3" high flow barrel spun cat and the flex pipe but the Y and the muffler came in and the muffler was bigger than it looked in the pic . . .dayum but the welds are great and it looks to be built well. on that note I also found this that seemed to be good knowlege, it also touches on the misconception and clarification of backpressure (I fell into this category)

The following excerpts are from Jay Kavanaugh, a turbosystems engineer at Garret, responding to a thread on http://www.impreza.net regarding exhaust design and exhaust theory:

"Howdy,

This thread was brought to my attention by a friend of mine in hopes of shedding some light on the issue of exhaust size selection for turbocharged vehicles. Most of the facts have been covered already. FWIW I'm an turbocharger development engineer for Garrett Engine Boosting Systems.

N/A cars: As most of you know, the design of turbo exhaust systems runs counter to exhaust design for n/a vehicles. N/A cars utilize exhaust velocity (not backpressure) in the collector to aid in scavenging other cylinders during the blowdown process. It just so happens that to get the appropriate velocity, you have to squeeze down the diameter of the discharge of the collector (aka the exhaust), which also induces backpressure. The backpressure is an undesirable byproduct of the desire to have a certain degree of exhaust velocity. Go too big, and you lose velocity and its associated beneficial scavenging effect. Too small and the backpressure skyrockets, more than offsetting any gain made by scavenging. There is a happy medium here.

For turbo cars, you throw all that out the window. You want the exhaust velocity to be high upstream of the turbine (i.e. in the header). You'll notice that primaries of turbo headers are smaller diameter than those of an n/a car of two-thirds the horsepower. The idea is to get the exhaust velocity up quickly, to get the turbo spooling as early as possible. Here, getting the boost up early is a much more effective way to torque than playing with tuned primary lengths and scavenging. The scavenging effects are small compared to what you'd get if you just got boost sooner instead. You have a turbo; you want boost. Just don't go so small on the header's primary diameter that you choke off the high end.

Downstream of the turbine (aka the turboback exhaust), you want the least backpressure possible. No ifs, ands, or buts. Stick a Hoover on the tailpipe if you can. The general rule of "larger is better" (to the point of diminishing returns) of turboback exhausts is valid. Here, the idea is to minimize the pressure downstream of the turbine in order to make the most effective use of the pressure that is being generated upstream of the turbine. Remember, a turbine operates via a pressure ratio. For a given turbine inlet pressure, you will get the highest pressure ratio across the turbine when you have the lowest possible discharge pressure. This means the turbine is able to do the most amount of work possible (i.e. drive the compressor and make boost) with the available inlet pressure.

Again, less pressure downstream of the turbine is goodness. This approach minimizes the time-to-boost (maximizes boost response) and will improve engine VE throughout the rev range.

As for 2.5" vs. 3.0", the "best" turboback exhaust depends on the amount of flow, or horsepower. At 250 hp, 2.5" is fine. Going to 3" at this power level won't get you much, if anything, other than a louder exhaust note. 300 hp and you're definitely suboptimal with 2.5". For 400-450 hp, even 3" is on the small side."

"As for the geometry of the exhaust at the turbine discharge, the most optimal configuration would be a gradual increase in diameter from the turbine's exducer to the desired exhaust diameter-- via a straight conical diffuser of 7-12° included angle (to minimize flow separation and skin friction losses) mounted right at the turbine discharge. Many turbochargers found in diesels have this diffuser section cast right into the turbine housing. A hyperbolic increase in diameter (like a trumpet snorkus) is theoretically ideal but I've never seen one in use (and doubt it would be measurably superior to a straight diffuser). The wastegate flow would be via a completely divorced (separated from the main turbine discharge flow) dumptube. Due the realities of packaging, cost, and emissions compliance this config is rarely possible on street cars. You will, however, see this type of layout on dedicated race vehicles.

A large "bellmouth" config which combines the turbine discharge and wastegate flow (without a divider between the two) is certainly better than the compromised stock routing, but not as effective as the above.

If an integrated exhaust (non-divorced wastegate flow) is required, keep the wastegate flow separate from the main turbine discharge flow for ~12-18" before reintroducing it. This will minimize the impact on turbine efficiency-- the introduction of the wastegate flow disrupts the flow field of the main turbine discharge flow.

Necking the exhaust down to a suboptimal diameter is never a good idea, but if it is necessary, doing it further downstream is better than doing it close to the turbine discharge since it will minimize the exhaust's contribution to backpressure. Better yet: don't neck down the exhaust at all.

Also, the temperature of the exhaust coming out of a cat is higher than the inlet temperature, due to the exothermic oxidation of unburned hydrocarbons in the cat. So the total heat loss (and density increase) of the gases as it travels down the exhaust is not as prominent as it seems.

Another thing to keep in mind is that cylinder scavenging takes place where the flows from separate cylinders merge (i.e. in the collector). There is no such thing as cylinder scavenging downstream of the turbine, and hence, no reason to desire high exhaust velocity here. You will only introduce unwanted backpressure.

Other things you can do (in addition to choosing an appropriate diameter) to minimize exhaust backpressure in a turboback exhaust are: avoid crush-bent tubes (use mandrel bends); avoid tight-radius turns (keep it as straight as possible); avoid step changes in diameter; avoid "cheated" radii (cuts that are non-perpendicular); use a high flow cat; use a straight-thru perforated core muffler... etc."

"Comparing the two bellmouth designs, I've never seen either one so I can only speculate. But based on your description, and assuming neither of them have a divider wall/tongue between the turbine discharge and wg dump, I'd venture that you'd be hard pressed to measure a difference between the two. The more gradual taper intuitively appears more desirable, but it's likely that it's beyond the point of diminishing returns. Either one sounds like it will improve the wastegate's discharge coefficient over the stock config, which will constitute the single biggest difference. This will allow more control over boost creep. Neither is as optimal as the divorced wastegate flow arrangement, however.

There's more to it, though-- if a larger bellmouth is excessively large right at the turbine discharge (a large step diameter increase), there will be an unrecoverable dump loss that will contribute to backpressure. This is why a gradual increase in diameter, like the conical diffuser mentioned earlier, is desirable at the turbine discharge.

As for primary lengths on turbo headers, it is advantageous to use equal-length primaries to time the arrival of the pulses at the turbine equally and to keep cylinder reversion balanced across all cylinders. This will improve boost response and the engine's VE. Equal-length is often difficult to achieve due to tight packaging, fabrication difficulty, and the desire to have runners of the shortest possible length."

"Here's a worked example (simplified) of how larger exhausts help turbo cars:

Say you have a turbo operating at a turbine pressure ratio (aka expansion ratio) of 1.8:1. You have a small turboback exhaust that contributes, say, 10 psig backpressure at the turbine discharge at redline. The total backpressure seen by the engine (upstream of the turbine) in this case is:

(14.5 +10)*1.8 = 44.1 psia = 29.6 psig total backpressure

So here, the turbine contributed 19.6 psig of backpressure to the total.

Now you slap on a proper low-backpressure, big turboback exhaust. Same turbo, same boost, etc. You measure 3 psig backpressure at the turbine discharge. In this case the engine sees just 17 psig total backpressure! And the turbine's contribution to the total backpressure is reduced to 14 psig (note: this is 5.6 psig lower than its contribution in the "small turboback" case).

So in the end, the engine saw a reduction in backpressure of 12.6 psig when you swapped turbobacks in this example. This reduction in backpressure is where all the engine's VE gains come from.

This is why larger exhausts make such big gains on nearly all stock turbo cars-- the turbine compounds the downstream backpressure via its expansion ratio. This is also why bigger turbos make more power at a given boost level-- they improve engine VE by operating at lower turbine expansion ratios for a given boost level.

As you can see, the backpressure penalty of running a too-small exhaust (like 2.5" for 350 hp) will vary depending on the match. At a given power level, a smaller turbo will generally be operating at a higher turbine pressure ratio and so will actually make the engine more sensitive to the backpressure downstream of the turbine than a larger turbine/turbo would."

 

That was very informative thanks for sharing.

Question, why would you bother shelling out for a high flow cat instead of just taking it off altogether? I mean its gonna be far from street legal either way right?

 

good question it will only as non-street legal as they know, and putting a cat on it will keep it more compliant the places I go to will pass it so long as their computer does and it has a few key items such as an egr, a muffler, an engine that is the same year or newer and cat. Plus it is better for the environment. :hide:

 

No need to :hide: we got zero emission enforcement here. Still I left the cat on my legend. Just wouldn't understand putting one on a track only car. But if it helps you get away with driving it on the street, I understand:bigok:

 

Ok as some of you know my laptop hard drive took an indefinate leave of absence and I am now trying to get by on 6gigs which Widows and its sub components I need take up about 5.9 of that but Iwas able to get the driver for my camera after three days and multiple viruses had to reformat a couple times lol. but here is what I have in mind for teh passenger side

Thank you for your patience

driverside is still to be worked through there's a lot less space over there.

 

PERFECT!:bowdown: :bowdown:

 

well not yet but it is getting there. The drivers side will be a bit more work, but I think I am going to do most of the mocking up on the spare engine.

 

Now that the camera is back up I can also show a pic of how I re-did the power steering reservoir to provide a little more space and create a more low profile look for the reservoir. After a week or so I will update as to how it is going but so far so good ( I did have a clamp I needed to tighten down a bit and a little sealing was required).

 

lookin good, your making alot of progress:thumbsup:

 

Our engine bays a looking more and more similar as the days go by.


~Dv8

 

Our engine bays a looking more and more similar as the days go by.

~Dv8

hmm Definately intriguing I can't wait to see your build

 

Telion, your project is looking good. I know you're lusting for the TWINS but have you considered SINGLE turbo but bigger?

 

Have I ever lol, infact I think about it everytime I look at the drivers side of my engine bay between the firewall and the wheel well, but I am sticking to this. Don't worry your not the first nor the only to ask this but my answer stands it. It will be a TT and what's better than a set of twins? well once I hammer out all the details the answer will be a bigger set of twins

 

I'm digging that power steering location/container. If it works out please post what is all needed I would LOVE that for my car.

 

I used an oil catch can and Y-d into the cooling unit. Less the fact that it still seems to be leaking a little from somewhere it is working great. Personally I would say spend the extra 10.00 for one that will not leak. this one was like 25 or 30 dollars. My concerns were the Y-connection and the smaller size but that has not proven to be an issue at this point.

 

Thats a very slick looking ps container, definitely good thinking on your part! I'm looking forward to the final product

 

Don't run out and buy one yet, as it turns out the flow of the fluid needs to go in a certain direction in order for the speed sensor to function properly. I was under the impression thata it was a gear driven (rotational speed calculation, apparently not). I had it working and not (at least I thought) having any adverse affect on the speed sensor. But thien when I re-routed the flow of the fluid the speed sensor has since stopped working. Thinking thiswas a coincidence I ran to the junk yard and grabbed another speed sensor (which I am yet to install). Now being very speculative of coincidences I thought I would do some home work on the functionality of the speed sensor and it is dependant on the flow of the fluid in the power steering system. So I am going to re-route it the way I had it or in a fashion that is cohesive with the manual and see if it again works and if it does I will validate the speed with my GPS, so stay tuned.

 

Ok my suspicion (sp*) was confirmed hooked it up a different way (after snagging another VSS from the junkyard) and my speedo worked again bad part is once I drove it back home from work pressure still built up somewhere, possibly before the internal VSS one way check valve and caused my girl to spray a bunch of PS fluid once I got home. I am going to go back through the service manual again.

 

I may be totally off here, but it would seem to me that the routing would not be as important as mainting the hoses at the same levels as the original unit. So its still gravity fed.

 

yeah your a little off the direction of the flow is what is most important and I think I got it working now so it is all good start your car then look at the fluid as it spins inside the container if you don't have it flowing in the correct direction the flow is stopped by a one way check valve, secondly if you flow too much fluid to the VSS without the ability for it to feedback into the cylider the pressure of the fluid builds up and the built in relief valve does its thing . . .all over your driveway

 

Interesting.. I am always seeing threads about mystery power steering links.. I wonder if thats the cause.. The relief valve i mean. I learn something new about the legend everyday:thumbsup:

 

can anyone give me some information on the injector Resistor . How much power that resistor can run ? can it run 550cc Injectors ?

 

I agree with DandDee, but I will point you in the right direction, do a search on 450cc injector or DSM injector and it needs to be a low ohm injector, can't remember the ohms but this should help you begin your quest then reply in one of those threads.

 

this might not be the best place to ask the spot light is kinda on Telion but someone will help u out im sure

 

i would like to chip in. i havent read the whole thread, but giving you somewhat of an idea.

if your going to run twins, dont search for a turbo that has 63 trim or bigger. unless your looking for 850+. i would consider running two big 16g turbos. they are off a evo 3 in japan. you could get them off slowboy racing for 500 a piece. they're pretty small, but accords car squease out 400hp off a single turbo.

now with a 16g turbo you could have 3 cylinders spool up full boost around 3500-3800. with a valvetrain that could rev up to 8k. your going to have 5k rpm of full boost on both turbos.

mounting them is not that difficult. 3000gts mount them right off the header. im sure we could to.

i would invest in making a intake manifold similar to DV8s, but instead of 1 tb. try to get 2 in there. that way there will be no disrupted airflow.

then using the intercooler your using route each turbo pipes opposite side of the car. like you already pictured before. and you could have pipes comming from each side in the engine bay.


just my .02 cents telion.

 

i would like to chip in. i havent read the whole thread, but giving you somewhat of an idea.

if your going to run twins, dont search for a turbo that has 63 trim or bigger. unless your looking for 850+. i would consider running two big 16g turbos. they are off a evo 3 in japan. you could get them off slowboy racing for 500 a piece. they're pretty small, but accords car squease out 400hp off a single turbo.

now with a 16g turbo you could have 3 cylinders spool up full boost around 3500-3800. with a valvetrain that could rev up to 8k. your going to have 5k rpm of full boost on both turbos.

mounting them is not that difficult. 3000gts mount them right off the header. im sure we could to.

i would invest in making a intake manifold similar to DV8s, but instead of 1 tb. try to get 2 in there. that way there will be no disrupted airflow.

then using the intercooler your using route each turbo pipes opposite side of the car. like you already pictured before. and you could have pipes comming from each side in the engine bay.

just my .02 cents telion.

Are you kidding me? big 16g's? Wow talk about a non efficent turbo. If any 16g he should get a evo 16g not a 16g but 18g's can be had for cheap.

 

Are you still looking for turbos? I found a great deal on a pair on my local craigslist. Ill send you the link if you think you might be interested. If you think you want them ill even go check them out, pick them up and ship them to you, just lmk.

 

Thank you both of you for your suggestions as for the dual intake manifold I had considered it but came to the conclusion that the 2 in 1 out FMIC will suffice for now since it would be one more unknown to throw in the mix of unknowns I will already be dealing with. as for the exhaust manifods aww-shiet I have decided to switch them forward into the engine bay so size is a lot less of an issue in that regard. As for buying additional turbos, not yet guys let me make this thing run first. There are still a few odds and ends I need to pick up like a boost gauge, an oil pressure gauge and a little bit of
1 1/2" pipe for the headers.

Now on a side note till I make a DIY thread about it I have worked out the kinks in the power steering reservoir. I opted to not use the El cheapo ($23.00 Ebay special which I would advise others not to use either) and went with the Zero1000 catch can. It has larger diameter holes that don't prohibit the flow of the PS fluid and seals much betterso there is no longer a leaking issue. The size is about the same but the quality of the two items are worlds apart and this way I can use the custom made aluminum one that I picked up as a catch can for the turbos (it's well made and very pretty lol).

As for the project over all I am kind of in a holding pattern till I get this welding situation worked out. What I really need to do is take my engine that is on the stand put all the needed parts on it that I need to work around so that I have a decent out of car template to work with. Hopefully I can get the steel ordered soon so I can have these headers whipped out then get this b!($% welded up

 

Ok I will keep the power steering reservoir subsection short by just adding a few pics the rest is fairly self explanitory and if someone has a desire to do this I will do a seperate thread the includes how it is routed.

PS please excuse my car it is currently under re-constructive surgery

 

Even though this is the less exciting part to getting this car where I want I thought I would through in the fact that I (kinda) got my eonon (cheap) to recognize a video signal, the aux input still does not work but I figured I would use the backup light. The down side no sound while watching gauges

Now of course I will still use a mechanical boost and oil pressure gauge.

 

Great !!

Let me know how you make realtime log system.

I couldn't get any useful signal from CN400 port.