new turbo build for the banshee?

[ericjon262]

<ramble>

Howdy, I've been thinking about the car quite a bit lately, one of the things that had been bugging me the most about the car, other than it not running, is the piss poor exhaust, both pre and post turbo. I'm starting a plan to redo all of it, starting at the exhaust ports, leading all the way to the tailpipe.

at this point, I like the simplicity of a log manifold, both for ease of construction, and for space constraints. while a header style manifold should produce better response, more power, and better efficiency, I'm not sure the increased effort, and costs, will really be worth it for my car. I think I may also be able to offset the losses, with some simple design improvements. right now, my biggest concern is longevity, how do I make this car last a long time, under abuse, no cracking manifolds, or exhaust leaks.

at this point, cracking is the biggest concern, a straight log will cause a two different lengths of pipe to exist, causing a stress to occur at the junction. this stress will be proportional to the lengths of the pipe used, I was planning to use schedule 40 weld el's and pipe for the manifolds. I have a couple of options here, one, is to ignore it all together, and make something akin to the TGP or Fiero manifolds. The other way, in a log style manifold would be to have the pipes exit and turn down before connecting to the log, similar to Will's rear manifold.

wills exhaust.JPG (164.64 KiB) Viewed 1709 times

now the pipe can expand and impart a small amount of torsion and a small amount of leverage to the runners instead of just leverage. unfortunately, space constraints will prevent the downturn, interference, with my alternator prevents it from working. which leaves me with option "A".

I have a few plans to help with the efficiency issues of the log, mainly introducing a taper to the log. similar to my mild steel logs that are currently installed, but smoother and tighter to the head, and maybe ceramic coated.

so far, it's looking like I'll have about $700-1000 in materials for the exhaust, a proper turbo will probably add another $1000-1500. I'm trying to decide what to do for the actual turbo, I want to get out from this knockoff Chinese crap, I'm trying to decide between 2 options, both are similarly priced, but offer distinct differences. option one, a proven Precision turbo, like a 6262, they're light, nice flanges are readily available, lightweight, and spools pretty fast. option B, a variable geometry turbo, maybe something like a holset 351 VE, very fast spooling, with an acceptable top end, downside, they're big, heavy, flanges aren't as common, and requires an actuator for the vanes, I should be able to take some of the weight out, lots of material i can remove, with a grinder if I have to. I like the idea of the responsiveness, and big top end of the 351VE, the question is, how difficult will it be to dial in. I like the simplicity of the conventional turbo as well though. the concept of the 351VE on a gas car has been proven to work on Old Europe, with a built-ish 3800. I like the idea of the holset, but I'd also like to have one in my hands to see just how hard it will be to package. I'd prefer not to lose what little is left of my trunk.

I'm not planning on doing all this before getting the car running again, but when I do get a stock shortblock, I'll have a mockup piece to use to build off of.

</ramble>

Thoughts?

[Shaun41178(2)]

Buy mine. Cheaper and less time consuming

[ericjon262]

Buy mine. Cheaper and less time consuming

no.

I have seen with my own eyes the port mismatch between TGP manifolds and 3500 heads, it's not insignificant, and can't be ported away without eliminating all of the mating surface.

[Shaun41178(2)]

It is insignificant. You used 3500 gaskets on a tgp manifold to make your comparison. Everyone knows even the 3500 gaskets are way bigger than the actual exh port of the head.

I used a tgp gasket on a 3400 head and there was a smidge of overlap at the bottom of the port. Its a fact but there is no convincing you. 3500 exh ports are same as 3400.

You know more than me which is why its taken you 5 years to still have a non running swap and wanting to redo the whole thing while at the time you were building it, claiming you were doing it right the first time.

If anything else I will sell you my 6765e billet turbo for 900 obo.

[Shaun41178(2)]

Or you can find a new borgwarner in the 66mm variant for around 600 bucks.

Those are good turbos for the price point.

[ericjon262]

It is insignificant. You used 3500 gaskets on a tgp manifold to make your comparison. Everyone knows even the 3500 gaskets are way bigger than the actual exh port of the head.

I used a tgp gasket on a 3400 head and there was a smidge of overlap at the bottom of the port. Its a fact but there is no convincing you. 3500 exh ports are same as 3400.

I did put 3500 gaskets on a TGP manifold, I also did many other things to verify and validate my concerns, most specifically, I traced the 3500 port on the head, and then lined the bolt holes of the trace with the bolt holes on the TGP manifold. not only does running the TGP manifold result in a restriction in the exhaust port on a 3500 head, but it leaves an extremely small amount of area for the manifold to seal to the head, such that I believe it would greatly increase the risk of an exhaust leak, or gasket failure. It was a very carefully thought out decision not to run the TGP manifolds, I had them on hand, and the hardware to use them, I did not, and still do not, think they are a viable option for a 3500. you did not run 3500 heads with the TGP manifolds, you used GEN 2 heads, which the TGP used, so it's no surprise that you didn't experience any problems with them.

also, 3500 exhaust ports are not identical to 3400 ports. I have had both in my hands, they are slightly different, or at least early 3400 compared to 3500.

You know more than me which is why its taken you 5 years to still have a non running swap and wanting to redo the whole thing while at the time you were building it, claiming you were doing it right the first time.

I won't say I know any more or less than you know, I will say, in the process of building this car, I have learned quite a bit about what "right" looks like, things like having a tucked wiring harness barely visible to the naked eye sounded like "right" when I built the wiring harness the first time, the forged pistons and rods sounded like "right" when I had the engine built, the oversized oil drain for the turbo sounded "right" when I made the hoses. in reality, many of the things I did, weren't the wrong way to do them, but they were overly complicated, or overly expensive for no reason. I didn't need to spend whatever silly amount I spent on the fancy rods and pistons, the engine can look good with the harness visible, plumbing and routing an oversized line is a PITA and not necessary. I can say that I have learned a lot about what "right" really looks like. My biggest mistake with this car, was not having a complete plan from the start, and sticking to it. I bought the 3500, and then I bought a 4 speed. then I bought an F23 because the 4 speed wasn't good enough for some reason. I bought stuff to make a nice set of headers, and almost finished a nice set of headers, then bought a turbo. I was going to turbo the stock 3500, then I bought a reground cam, ect until the snowball became a bit ridiculous. it got to the point where I had 100 eggs, in 150 baskets. I made many bad decisions, and thankfully, I have been able to see those bad decisions as a learning point, and something to improve upon them. now the car is much more well planned, it has proper engine mounts, it has a proper wiring harness, the plumbing is well routed, and leak free. I'm to the point that I can be proud of the work I have done, and not embarrassed by piss poor welds, or ugly poorly done wiring. has it taken a long time? yes. longer than it should have? yes. do I wish I had done things differently? yes, but I don't truly regret the bad decisions, I've gained more experience from this car, than I can ever quantify.

If anything else I will sell you my 6765e billet turbo for 900 obo.

I'll definitely keep this in mind, if you still have it when I get to the rebuild process, I'll probably take it.

[ericjon262]

not really much to update ATM, I am looking into several different turbo ideas though.

Holset 351 VE
Garret Duramax VGT turbo
or a "regular" turbo like Shaun has offered me.

I'm also looking into materials for the hotside, at this point, I feel like bang-for-the-buck, is 304L, it should last fairly well, and I may go as far as having the inside of the tubes ceramic coated. I am planning to have the flanges custom cut to ensure a close match to the head.

Most of my time as of late has been devoted to getting my garage fixed up so I can get the car in and start work. I'll start a thread for the garage when I'm not at work.

[ericjon262]

I've been giving this some thought lately, and I have decided that a log will most likely be a better performer for one major reason, surface area. a multi runner header style allows for pulse tuning to some degree, but has 2+(being conservative) times the surface area of a simple log, which means it has drastically more surface area for the exhaust to lose energy to ambient, before it even gets to the turbo. I haven't done any math to prove it, but the logic works. also, with a log style manifold, it's relatively easy to make a heat shield to go over the whole manifold, whereas a header, wrap is just about the only option. the 60V6 also has another advantage playing in the log's favor, it's firing order, 1-2-3-4-5-6. the cylinders fire in order, sequentially, down each bank, which should help minimize "crowding" in the manifold, or so I think. I have a good book on exhausts at the house, I'll tear into it a bit and report back any new ideas or confirmations.

Edit:

TLDR

Log may be better than header.

[ericjon262]

I've been thinking about this quite a bit lately, ordered flanges and everything, now I'm starting to try and figure out what to do with the turbo.

I want something with a V-band inlet and discharge, and that will spool fast, thinking something like one of these:

"590 hp rated"

https://www.precisionturbo.net/Street-a ... 58-CEA/225

"700 hp rated"

https://www.precisionturbo.net/Street-a ... 62-CEA/634

anyone have any recommendations? at this point, I'm preferring quick spooling to ultimate top end power, and I think 500 hp and fast spooling shouldn't be an issue right?