Gotcha, I don't understand it to well either. Plan on talking to someone that knows what they're doing before I just start ordering stuff. Any reason for not building a log manifold like kbracing?
CK5
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Stomis' 94 Street Truck - Snail Trail
- Thread starter Stomis
- Start date
Stomis
Professional Amateur
I dont exactly have a reason. I dont mean to sound like a fab snob but theres just nothing appealing about a log manifold to me. Its like that kid in school that did the bare minimum to pass. The only real advantage they have is you can build them to actually support the weight of the turbo. With my turbo placement thats really not an option. It needs to be mounted to the frame with a support. Plus I think @folkenheath raises a good point that you're loosing velocity when you unevenly dump runners into a big fat tube. Runners and velocity are the name of the game when it comes to spooling a turbo fast. Thats why I turned down the free set of 1-7/8 to 3in up and forward headers I was offered and found these 1-5/8 to 2.5 that will get crunched down further into 2-1/4 hot side.
Very true, I can see giving up alittle spool time with a log manifold. Being able to mount the turbo is the biggest draw for a log manifold for me, well that and packaging in a small space. Lots of people still make big power with log manifolds and flipped oem manifolds.
Stomis
Professional Amateur
I wouldn't even compare log manifolds and flipped oem manifolds. There's really nothing wrong with flipped oems, my buddy runs them.
Also making big power and driveability/spool time or boost curve really isn't the same thing.
Stomis
Professional Amateur
Well the shorty headers showed up. From eyeing it up they look like they might just fit perfect. Fingers crossed. My vbands will be here tomorrow and IDK where the **** my t4 flange is. Its been 5 days and Ive got no tracking number. Not really happy, calling them tomorrow...
Stomis
Professional Amateur
Made some room
Mounting wound up easy. Got it way lower than I thought I could.
Flipped ebay procomp shorties. I could not find anyone that tried flipping a manifold like this. It was either everyone used stock manifolds or up and forward and I knew up and forwards werent going to work for me, the turbo is too low and it would have hit my alternator. I did some minor trimming on the passenger side and they went right in like they were made to go this way. Im going to pick the motor up a tad when I solid mount it just to help with my steering shaft clearance. Shaping up good though. Going to pull the motor, cut my old mounting tabs off, stick it back in, make new tabs, take it back out reweld, paint, put it back in, make a hot side
Fun fun
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Stomis
Professional Amateur
Grinding isn't fun when you're sick...
Stomis
Professional Amateur
Wound up picking the motor up about an inch. I really didnt want to invest too much time into steering shaft routing. I realized if I picked it up a little bit I could sneak a 2 u joint straight shot steering shaft in there so I opted to do that. Probably knock the hotside out on wed night. Gates and BOV are suppose to be here this week, they were back ordered from their blackfriday sale. After the hotside and down pipe its going to get a little spendy. Ive gotta open the motor up and change the cam, check the bottom end out, pull the pistons and open the ring gap up, reassemble with the new heads and a thicker headgasket. Fab wise I need to make my intercooler. Im kind of excited to give making that myself a shot. It'll be the first intercooler Ive done, go big or go home I guess.
You weren't joking, turbo headers on already! saweet!
I'm glad you went with the tubes instead of the cast. I know you can make a lot of power on cast manifolds with turbos, but I can't do anything but wonder how much faster the same setup would be with the proper tubes. Plus you don't want to be one of those guys that makes a lot of power along with a lot of heat since it has 3x more exhaust backpressure than intake boost.
I'm glad you went with the tubes instead of the cast. I know you can make a lot of power on cast manifolds with turbos, but I can't do anything but wonder how much faster the same setup would be with the proper tubes. Plus you don't want to be one of those guys that makes a lot of power along with a lot of heat since it has 3x more exhaust backpressure than intake boost.
Stomis
Professional Amateur
This hot side should be good to 1500hp-ish. The nice thing about the S400 is I can go like all the way up to 88mm i think with the same turbo footprint. $140 headers were worth it to me and honestly IDK if manifolds would have works or not but I have literally zero mods into those headers other than welding the Vbands on.
Stomis
Professional Amateur
Mergelicious
Stomis
Professional Amateur
You can have all the room in the world but one thing in the way and things get complicated... Guess it was a cost of mounting the turbo so low...
Stomis
Professional Amateur
I did. Part of the reason I didnt do it was 1) I had loads of 2-1/4 and would have needed to step up to a larger pipe 2) I would have been waiting around for a t4 to X size transition because trying to get a single pipe to fill that flange without the proper swage is pretty difficult, I know because Ive tried lol and 3) I think my passenger side routing would have been kinda funky; I would have wound up going down, forward merge and I hadnt really set where I wanted my driverside crossover to be.
Was it possible, sure. Maybe even easier in hindsight, but a lot of the difficulty I had getting out of the gate and needing that nutso merge came from putting the turbo so low. If it was 8-12inches higher like everyone else in the truck world puts them the flange would have been well away from the steering and well away from the frame to come over it. Wanting my weight lower and the turbo stuff up point forward complicated things to say the least.
Is there a reason you need to make the bends going into the turbo flange so sharp? Its almost a sharp corner on the ID. J-bends aren't that expensive and a lot less time consuming than all those pie cuts, and the turn wouldn't be so sharp, more smooth and flowing.
Stomis
Professional Amateur
The merge pipes are set at 25* which was kind of a sweet spot for not choking down the dual 2-1/4 hot sides so that was really my thinking there. I will say Im not an utmost expert on flow dynamics, entry angles, bend radius' etc. but what I did isnt unfamiliar of some of the merges available on the market. Even some of the vibrants have entry angles like the one I made, not all but some. I could see how the entry angles may cause some turbulence but Im kinda going to fallback on the age old turbo mantra that everything is under pressure, sizing, transitions, etc arent as crucial.
As far as pie cuts go, I have plenty of J bends laying around, when I take a picture of this thing mounted you'll understand my thinking on pie cutting and getting it offset as fast as I could. 100% necessary perhaps not. Its hard to tell in the dark picture. Im fairly certain the tight radius made by pie cuts isnt going to hinder anything vs a mandrel bend. The pies are done properly at 9* steps.
In all reality even if say I rebuilt this after dynoing and made a shallower merge and eliminated pie cuts whats the real expectation you think you would pick up? 3hp? 10hp? Even 20 hp? Smooth flow is never really going to affect spool time which is the most important thing to consider when sizing/building a hotside. The same reason I didnt want to do 1-7/8 primary headers... Im certainly not a turbo expert, I can build, I can do it nice and make shit fit good and work but at the end of the day this is only my third turbo build. Ive been trying to learn a lot from a friend of mines mistakes with his turbo builds and hes read yellowbullet up and down, left and right.
Shit theres a lot of guys out there with cobbled together booger welded stuff working awesome. Its just not me, I kinda strive to make it better every time and understand what could be fixed. I do always appreciate your counter points on my work, you and @Justin V are really the only people that every say "Hey why did you do this like this?".
On an aside, tigging aluminized pipe isnt fun...
Stomis
Professional Amateur
Hotside all done. Still waiting on my Gates.
Great work, I really like the way you mounted the turbo, routed the headers & plumbed the hot side.
Are you concerned that there is no compliance between the engine and the turbo? The reason I'm asking is I'm trying to piece together a similar set up in an old AMX and will have to mount the turbos low and forward. It looks like you have a solid mount for the turbo and I'm assuming the engine has solid mounts too which is what I'm planning on, but I'm worried about stress on all the tubes between the two being a weak point. I might be over thinking things...
Are you concerned that there is no compliance between the engine and the turbo? The reason I'm asking is I'm trying to piece together a similar set up in an old AMX and will have to mount the turbos low and forward. It looks like you have a solid mount for the turbo and I'm assuming the engine has solid mounts too which is what I'm planning on, but I'm worried about stress on all the tubes between the two being a weak point. I might be over thinking things...
