Na Exhaust Manifold On A Turbo?

[AthruC]

...let the fun begin. Long story short, I had an '07 SR 6MT that I planned on keeping and modifying, but I caught a bad case of Vagon envy. I picked up an 01 T5M (currently for sale) thinking I'd be content, but wanted something more unique w/ AWD... Fast forward to today and I have a 98 Saffron VR sitting at Justin's shop waiting to be modified. I'm getting a list together and trying to put all my ducks in a row and figured I'd consult the creative folks over here on VS

The concept is:

2.4L block

P2 R head (ported/polished)

NA cams??

Forged H-rods

Pistons??

R crankshaft (balanced)

M66

Custom FMIC/CAI

Turbo Tuner ECU (with raised redline and fuel mapping)

Custom tubular exhaust manifold w/ T4 flange

...and here is where I get creative. I have two BMW turbos from a 335 on their way to experiment with... if that doesn't work, I have a flange to throw on an array of turbos.

So here is where the real questions begins - have any folks taken a NA manifold and cut off the bottom of it to weld on a bend and turbo flange? It looks like they are almost-equal-length tubular headers and could be readily made to work with a turbo setup with not too much effort.

Flame suit has been on for a few weeks now :P

[bum2kev]

With the P2R head you will need to run P2 Cams. personally i would just run the stock cams and play with the timing of the 1 cam you can.

the turbo would be sitting to low... also you would have firewall issues. the turbo needs to be able to drain to the oil pan. just go with an R manifold, you arent going to be maxing it out at all lol.

all the mods you are talking about there be prepared to be spending ~10k+

[magicaljake]

So here is where the real questions begins - have any folks taken a NA manifold and cut off the bottom of it to weld on a bend and turbo flange? It looks like they are almost-equal-length tubular headers and could be readily made to work with a turbo setup with not too much effort.

that is EXTREMELY intriguing!

i have a 850 na manifold with a spanked flex joint...btw

[AthruC]

R manifold is good to 400-450HP, etc... yes, I am aware. I want to get 'creative' and would need to modify the manifold regardless, so I'm looking for a solution that is already somewhat in place, and looking at the NA manifold, it looks like it could easily be modified to work for what I'm doing - so I was curious if anybody else had tried it.

...and yes, I will be spending WAY too much money :(

[AthruC]

...for reference:

[BlackT5]

T4 flange? What size are the BMW turbos?

[AthruC]

The hot side of the compressor is actually part of the manifold. I'm not 100% on THIS idea but I was going to see if I could find another turbo that would mate up, or cut the manifold off and weld flanges on. Worst case, I use a single turbo (was going to be stupid and try a 'twin' setup, just because I can ) and give my girlfriend the turbos for her car (335xi)...

They are Mitsubishi TD03's.

I was going to try sequential but decided that this would be a MUCH easier route WRT plumbing and fabrication.

The goal is to make the car truly unique, with careful attention paid to 'power under the curve' - I HATE the ridiculous turbo lag that some of the monster turbos have. I think if I do end up going single turbo, GT28RS would be the largest I'd go.

D'oh, meant T25, my bad.

http://www.turbobygarrett.com/turbobygarrett/catelog/Turbochargers/GT28/GT2860RS_739548_1.htm

[AthruC]

lol, duh, I think I could have used the old T6 turbos too (I might do that).

Same TD03 housing, different impeller. I could possibly steal the hot sides from these suckers.

[TryingBe]

All I have is the picture, no idea if it fits in the car or not.

[mdlimy]

eh waste of time/effort, if you want to get creative, drop a bunch of money on a custom tubular exh mani or just p&p the shit out of an s60r mani. i dont think i would trust an exh mani made from a stock na header, they never see as much heat as a turbo manifold in the first place.

As for the twin turbos...do you care more about just doing something different or more about doing it right and making good power? twin turbos wouldnt be bad, much less lag but theres a reason people ditch them for a bigger single turbo, not to mention there just isnt much room at all to play with.

[AthruC]

Good point about the heat. I'll most likely get a hold of a NA header next week to 'feel it out' and take it from there. I don't think the heat differences are as drastic as you might think though.

I was more curious as to whether or not anyone had done it, as it seems like a rather decent idea to me (in theory, based on the design).

Re: twin turbos vs. 'one big turbo' - while the larger turbos are more efficient while boosting, as I mentioned, I am looking at 'power under the curve.' Having had a 335xi as a DD for a while, I fell in love with the almost nonexistent turbo lag. This car is to be my DD, not a track/drag monster, and useful, immediately available power is what I am looking for. Hell, I wanted to find a V8 from an XC90 of S80, but a 5 cylinder seems a bit more practical (for the moment). It was the mounting points and the availability of that motor that concern me at the moment.

The idea - get a fairly 'bulletproof' block, forged rods, raise compression a hair, and have at it with these two snails.

Trying, where did those pictures come from? What was the application? It doesn't look like the NA manifold (which does travel down a bit - this one looks like it shoots directly into the firewall). That does show the basic gist of what I'd want to do - cut off the manifold right where the logs collect and throw a mandrel bend to allow room for the turbo(s) to bolt.

[BoostedBrick]

I think you would run out of room pretty quickly trying to use the NA manifold. You could use the flange though, and cut off the pipes and weld up some of your own as a cheaper and easier way of a custom tubular design.

I have to admit, twin turbos would be pretty cool, and definitely unique, but again space would be very difficult, not to mention the astronomical cost (you now need two sets of custom oil and coolant lines, an oil pan to accomodate a second return, two sets of pipes to the intercooler, two intake pipes etc. etc.). But if you went with a good ball-bearing turbo with a smaller turbine, like a GT30-71, you could spool it quickly with a good tune and still make lots of power. I doubt if you would have much lag at all, you could even look into twin scroll if you are really nervous.

But it sounds to me like you really want to go twin, and if thats the case (and you can financially justify it) go for it man, it would be one of a kind. Bring us some pictures!

Gook luck on the project.

[mdlimy]

maybe its because im tired as hell and this is the last post before i go to bed but the twin turbos sound like a better idea now than earlier

I think it could definetly be pulled off, but the na manifold is definetly a step in the wrong direction, the design of the manifold is going to be the MAIN deciding factor on how you will squeeze those 2 turbos inbetween the motor and firewall but i think it can definetly be done, side by side.

[AthruC]

There is enough room for two teenie tiny turbos, but yeah, looking at it more and more, using that NA manifold might not work (for my application - I think it could work, quite easily, for a single turbo and I might just cut one up and weld it for giggles).

I would be doing most of my own fabrication to keep costs massively down, and I have most of it already planned out (for the most part). 5 tubular headers to a joiner, then split L/R to each turbo. Single CAI split just before the turbos with a "Y" (basically what I'd be doing with all the inlets/outlets), but the rest of the layout will basically be the same. A true dual CAI and true dual exhaust would have been sweet (still going dual), but alas, the car only has one MAF and one catalytic converter

I'd be making my own oil and coolant lines to the turbos of course, but I was worrying last night about whether the stock oil pump (and water pump?) would be able to provide ample cooling/lubrication to TWO turbos. I could easily wire up an auxiliary water pump, but is there a higher capacity oil pump that was available? On the P2 R's maybe?

...and I know that many people have been flamed in the past for 'twin turbo' ideas and I've seen the 'it'd be cheaper/easier to blah blah blah' responses, but it's been done before, and it's been done well as of late (ala BMW), and I'd love to put together something truly unique.

*edit* been done before successfully in a production car (not like the older T6 fail )

[BlackT5]

I think you are WAY over complicating things and just setting yourself up for disappointment and a lot of headaches.

Throw some rods in it with a 19T and "S60R" manifold. or if you want a little more, throw on a gt2871. get turbo tuner and be done.