Budjet/DIY Twin Turbo 406 Malibu Wagon - parts cost update page 4

[dragginwagon406]

First off, I am a few weeks into this project and have posted before on another site but this site seems to get more feed back  .  Starting a project like this is easy.   Keeping up the ambition to finish it  takes practical advise from knowledgeable people and the encouragement of many.  So to that end, here goes.

I am nervous about taking a good running 3900lb sleeper and risk going slower but I think sometimes if you want to make an omelet, you must be willing to break a perfectly good egg.

So here is my current setup:

406 4 bolt mains...FWIW
10.85 CR Keith Black hyper pistons
6" Lunati Street Race rods
stock crank
E-Tec 200 heads
292H Comp Cam
Comp Pro Magnum 1.6 ratio
Super Victor intake
750 vac sec Holley
1 5/8" Hooker headers - badly mismatched to the heads
3000 stall Hughes converter
4.10 8.5" ring gear rear end
275/60 Dunlop Radial GT only - I am not willing to put slicks on...yet
Best ET 11.47@116 with a 1.60 60' on 100 HP Nitrous on 93 octane

****Edit****
You need to register and login to see the pictures.  2-6-07 Changed first post pics to include turbos.

[dragginwagon406]

I have researched this extensively before deciding to try this route and here are my observations and decisions.

Since this is a budget job, the turbo must be cheap.  This rules out new and with an engine this large, corretly sized singles are difficult to find.  But Grand National turbos seem plentiful and the math appears to be OK so I decided on twins sourced from 86 GN's.  As other people have found, turbo mainfolds for this car are problematic as the downpipe would interfere with the heater box.

So I am making my own headers in order to mount the turbos further forward.  

For header construction, I have decided to follow Grapes Apes http://www.grapeaperacing.com/camaro/ path of using the schedule 40 1.5" pipe.  I am making all my flanges - royal PITA.  I will be using a stall flange adaptor to allow this size 1.90" OD x 1.61" ID and at this point I only have half a clue a s to how I can neck it down to the 2 1/8" inlet of the GN turbos.  I guess I'll need some help from an "adaptor kit"

I would prefer to have internally wastegated system for size and simplicity but my turbos were missing the elbow/wastegate assemblies.

I have not decided on a BOV - I am open to suggestions.

I know the compression needs to come down ASAP but I will get to that soon enough.

After much comtemplation, I am certain I will run a 650 DP carb and modify it myself according to Hanger18's guide http://www.hangar18fabrication.com/blowthru

I would like an EV carb hat but do not know if it is in my initial budget.

An itercooler from a Power Stroke would be nice but looks like it may need modified slightly to fit nicely.  Malibus have tiny front ends

For gears, I will go with 3.08's...this should help with the highway cruising as I do not have a trailer

[PRAY HRD]

welcome. nice video, that car moves pretty good. i bet you caught that mustang driver WAAAAY off gaurd as well as quite a few others. i always liked the malibu style like that. get 'er done man!!!

[dragginwagon406]

Some before shots

Air Inlet Systems ram air.

I think this power steering hose may get in the way.

Current fuel filter and T for nitrous fuel pump.

Power block

[78maliboost]

hello, welcome to the board, Just wanted to say hi to a fellow malibu owner.

My malibu is getting treated to an 80mm siingle

[dragginwagon406]

To people who have not seen my car before, yes it does catch them off gaurd  .  If you like that video, here is another:

http://www.zippyvideos.com/4625310306262616/milan_11.52sec__116mph/


Maliboost, best wishes with your project.

I got the turbos hung tonight.  I still need to put a slight bend in the mounting brackets to help clear the inner fenderwells and aim the compress outlets toward the intercooler inlets.


Driver's side

Passneger's Side

I am also starting to layout the header flanges - It sucks being a cheap bastard - what a pain.  I will end up drilling the corners of the 1.55" squares and cutting out the rest with a jig saw.

[METAL MAN]

You can buy steel flanges for dirt cheap. You'll have more time and money in to making them yourself and it'll be hard to beat ones that are laser cut.

[stock lx]

what type of fuel system are you gonna run with the blow thru?

[dragginwagon406]

Metal Man:  Define dirt cheap 

stock lx:  I am weighing my options at this point...I have extremely low resources for this project so I cannot see buying the high dollar pump and regulator yet.  I already have the mechanical Carter strip pump, I will boost reference it as shown in this thread.

http://www.turbomustangs.com/smf/index.php?topic=25144.0

As for a carb, I will modify a swap meet 650DP as per Hanger18's instructions.

http://www.hangar18fabrication.com/blowthru

[METAL MAN]

Metal Man:  Define dirt cheap 

$36.00 per side for nice laser cut SB Chevy flanges. Figure you'll have an easy 2hrs plus into making yours and it's totally not worth it.

[Jackstand]

$36.00 per side for nice laser cut SB Chevy flanges. Figure you'll have an easy 2hrs plus into making yours and it's totally not worth it.

i agree.... 

the project is looked good

[dragginwagon406]

36 bucks is tempting but I still have plenty of time on my hands so I think I'll have a go at making them myself.

In looking at my setup, I think I may be able to get away without the stahl flange adaptor plates (1.5" schedule 40 pipe is about 1.875" OD causing interference with header bolts unless using the adaptor plates to relocate the bolts) by using longer header bolts and welding short sections of pipe for the bolts to run through.  Seems problematic if the tubes  were to shift but it may work.

I have taken some pictures of the mismatch of the gasket (Fel-Pro 1405) to pipe.  The corners mismatch badly and the flat areas of the gasket are actually slightly smaller than the ID of the pipe.  If I slice the edges of the pipe and bend the mismatched area outward (and the flat areas inward ever so slightly) it should transition well and give a little more clearance for the weld at the bolt holes.

[m j]

You can buy steel flanges for dirt cheap. You'll have more time and money in to making them yourself and it'll be hard to beat ones that are laser cut.

where? how thick?

[METAL MAN]

3/8"

[dragginwagon406]

Well, due the the AC box on the car, I cannot get away without using the Stahl subflange (pipe direction on cylinder #8 is limited to the forward direction - possibly as much as 30 degrees upward.)  Here is my idea for headers.  Definitely going to be a PITA clearancing the center piping to fit next to each other. 

Metal Man, do the dimensions look correct for port spacing?

[89JYturbo]

Is that CAD you used to design those headers?  Is that how guys are getting pipes that fit perfectly with no gaps!?  I recently attempted my first turbi header fabrication.  They came out decent, but I made a few bad cuts that ruined a $15 J-bend.

[dragginwagon406]

Auto Cad.  I designed using CAD then take the overall measurements and decide wether or not the design is practical(or even fits.)  The version I posted appears to end up too close to the AC box.   One of my design goals is to be able to use same header on both sides.  I will then make up the difference after the collector.  So, I'll try again.

[dragginwagon406]

89JYturbo:  I dig your Cavalier - it has got me thinking about putting a turbo a my Wrangler  , It is not a racer, but it could sure use a little more torque to spin those big tires.


OK, I think I've made a version that will work.  Seems to have ample clearance for both sides, now I need to find a way to reduce it from the nearly 4" ID down to the 2 1/8" inlet on the Grand Natonal turbos.  I've seen slide on collectors and and some fabbed from flat steel, but I think I'll make that decision after seeing how well the header construction goes.  One other comment:  on all the flange measurements I've seen, the exhaust bolt pattern centerline is offset downward between .020" and .040".  I'm curious to know why this is.  I can only speculate it is to compenstate for the "play" in the bolt holes allowing the header to "hang" down a litlle further than intended.

[sportbikeryder]

You can get the collector to be the size you want by cutting the weld elbows roughly in half where they meet. Check out metalmanfab.com in the turbo section or grapeaperacing.com in the camaro build-up / turbocharger section to see pictures.
John

[doesgo]

All I'm seeing is the dreaded red Xs instead of pictures above, is it me or does everyone see the same thing?

Anyway, I'm not sure if it's too late or you've already achieved a solution (since I can't see the pics), but here are a couple things I did on my SBC twin-turbo project that might help, or at least give some ideas.

For the header flange, I also cut my own.  $72 for a pair laser-cut isn't bad, but having more time than money helps make the decision an easy one.  Anyway, I used 3/8" steel for the flange and 1.5" weld els for the header tubing and ran into the same problem you did with the bolt holes.  My solution was to squeeze down the schedule 40 pipe where it was to be welded to the flanges to get it between the bolt heads.  That left a smooth taper back to the 1.5" round shape.  After the final welding, I went in with a carbide burr and cleaned up flanges to match the ID of the pipe and match it as well as I could to the head ports.  Oh, and my welding skills suck, so be gentle! 



As for the collectors, I had to take the large cross section of four schedule 40 pipes coming together all the way down to the size of a T03 inlet, so I took a piece of 2.5" schedule 40, cut it into quarters lengthwise, and then cut some wedges to make the taper.  Worked out great!  All the cutting was a semi-pain, but it was pretty simple and very functional.




What a great message board, by the way!

[dragginwagon406]

doesgo:  Awesome tip.  That's one of the reasons I posted this project to begin with - to get help with the areas I am unsure about.  Unsure as to why you don't see the pictures.   Did you notice the offset in the bolt centerline toward the bottom of the flange (.030"), does this sound correct for port spacing 6.745" outside cylinders to inside cylinders and 1.721" between the middle 2.

sportbikrider:  Metmanfab's collector on the import header is top notch (no pun intended), I don't think I have those kind of mad skills yet.

[doesgo]

I guess it was something to do with my place of employment that was preventing me from seeing the pictures, we were having problems with the Web today in general.

You know, I made my headers back in early 2003 so I don't recall the bolt centerline offset issue, nor the port spacing.  Like you, I drew it up in CAD, I'll have to take a look tomorrow and check if I accounted for that, and also what the port spacing was.

One more thing.  Perhaps you've already considered it, but after you finish fabricating the headers, I'd suggest laying a weld bead around the ports on the engine side of the flange, then sanding/grinding them all flat.  I got the idea from my regular Hooker headers (which never leaked or blew a gasket since I bought them in 1989, through dozens of R&R procedures), and it worked great on my turbo headers.  I haven't got much time on the turbo headers, but they were leak-free when they were installed.

[89JYturbo]

Auto Cad.  I designed using CAD then take the overall measurements and decide wether or not the design is practical(or even fits.)  The version I posted appears to end up too close to the AC box.   One of my design goals is to be able to use same header on both sides.  I will then make up the difference after the collector.  So, I'll try again.

Thanks for the info. I don't have the engineering background to use and apply CAD, but may have to learn.  It looks very valuable if I could learn to work with it.  Do most fabricators use CAD for designing simple things such as headers?

[dragginwagon406]

I don't know if most do use CAD, but I'm sure it cuts down on wasted material for these who do use it.

[doesgo]

Yeah, it's certainly not necessary, but like dragginwagon said it can really help minimize wasted effort and wasted materials.  I used it to draw up my collectors (pictured above) before I did any cutting and was able to find out exactly the lengths and angles of the wedges to fit between the quartered pipe to make it mate properly with my primary tubes on one side and the turbo inlet flange opening on the other side.