[jdw_poncho]

Finally making some progress on my twin turbo project. I ended up with twin 78mm Precision turbos that will be run on a 512 IA2 run on methonal. Hope to have the engine on the dyno by the end of June if I get all the parts bought and the shortbolck built before then. At least thats what I shooting for, doubt I'll have it ready to run in a points class but at least I'll have time this year to test it out.

I still need to cut my old cage out and install a 25.3 cage, new rearend and re-do the tin work. Its going to be a tough few months trying to get it finished.

I almost got the "easy" header done, except for one tube I need to re-route. I'm sure the driver side wont be finished as fast. But luckliy I have to re-route my steering for the rack anyway so it wont go in the stock location.

I had 2" tube bought for this but it didnt take very long to figure out I couldnt get the radius I needed to clear the A-Arms so I went with 1 3/4" tubing the entire way. I was also looking for a 4-1 transition to the turbo. Everything I found was over a $100. I couldnt see paying that for 4 tubes and piece of 3/8" flat so I built my own. Did some research and figured out the correct angles need to make it work. Built it from .095 ERW tubing and 3/8" flat. I tried using the 16ga tubing but it was tough trying to mill out the miter cuts on thin tubing. The .095 allowed me to make bigger cuts and the tube still keep its shape.
I bought all the materials to build a set out of stainless but decided I wanted to use mild steel first in case I made a lot of mistakes.

My plan is to run low 5's in a drag radial class at Eddyville or KCIR. I would like to hope I can push the car to 4.90's but 5.20-5.30's will be a handfull to start out with.

I still have to get the second set of injectors installed and the entire fuel system bought and plumbed. March is going to be a expensive month.......
New JW trans should be here by April havent picked a converter yet.

[baron_]

Neat stuff. Very neat stuff.

[Johnny406]

W-O-W, now that is a stimilus package!!

[bankbook]

Nice build. Glad to see another turbo Poncho!

[cgeise]

Trust me - you will need to do them in stainless - the mild sreel will not last under the heat

[jdw_poncho]

Originally Posted by cgeise

Trust me - you will need to do them in stainless - the mild sreel will not last under the heat

What type of stainless did you have yours built out of? 300 or 400?

We use a lot of 304L tubing at work, I know the problem I have there and was concerned how long the stainless would hold up. It tends to crack easier after too many high heat cycles with fluid running through them. Maybe 409 series would hold up better?

I found a company that will digitize my current headers and bend them up out of stainless. The cost is a bit much for one set but if I figured my time plus materials its probably not that out of line. Espicially if they work well.

Do you run methonal or race gas in your car?

[jdw_poncho]

Originally Posted by Johnny406

W-O-W, now that is a stimilus package!!

Not for me!!! LOL Just trying to do my part.......

[Hooter]

What are you putting this in?

[meanone]

Cool build! The driver's side was easier for me, but mine's a different car. Who did you find that would digitize and reproduce headers? I thought about having a couple sets done. Probably not after I get a price, Lol!

[cgeise]

Originally Posted by jdw_poncho

What type of stainless did you have yours built out of? 300 or 400?

We use a lot of 304L tubing at work, I know the problem I have there and was concerned how long the stainless would hold up. It tends to crack easier after too many high heat cycles with fluid running through them. Maybe 409 series would hold up better?

I found a company that will digitize my current headers and bend them up out of stainless. The cost is a bit much for one set but if I figured my time plus materials its probably not that out of line. Espicially if they work well.

Do you run methonal or race gas in your car?

I run gas - C-16 - but I know that at 10 lb of boost on the chassis dyno they were glowing red - and the tune was fine - To be honest I dont know the spec on the tube - but could find out -

[jdw_poncho]

Originally Posted by Hooter

What are you putting this in?

69 tempest- I think I have a couple old pics when I first built the car.

Originally Posted by meanone

Cool build! The driver's side was easier for me, but mine's a different car. Who did you find that would digitize and reproduce headers? I thought about having a couple sets done. Probably not after I get a price, Lol!

I have the contact info at work. I cant remember the exact name and tried to google it but couldnt find it, I'll look tomorrow. You have to decide what you would be willing to pay before you call them. Its high if you compare to a single custom set and you still need weld them your self. But if I wanted to reproduce them it worth it to me. Thats why I thought itr would be worth the money if I needed to build a few sets over time. I found a couple shops that will do this, you pay for a min time for design and engineering then pay them to bend up the tubes. That first time engineering fee will hurt you if your not expecting it. LOL
I'll get the info

Did you use your stock steering box and shaft? I have a rack and pinion so I plan on re-routing my steering down under the headers through the cross member to keep it out of the way.

Originally Posted by cgeise

I run gas - C-16 - but I know that at 10 lb of boost on the chassis dyno they were glowing red - and the tune was fine - To be honest I dont know the spec on the tube - but could find out -

I'm seeing everything from schedule 10 304L pipe being used to 409 series. It seems like everybody uses it but I know how it reacts to heat. It work hardens and cracks after extreme heat cycles. I'm guessing my 16 gauge mild steel tubing wont hold up turning red very many times. I may end up with schedule 10 pipe instead of .083 304L tubing that I bought.

[taff2]

JDW, if you take your completed primary pipes to an decent pipe bender he will copy each pipe out of a single piece of tube,the only welds then will be at the flange and the collector. This is how I'll be doing mine (only using lengths of gas welding rod to make a 'template' of each primary pipe to take to the bender),and then I'm going to get the completed headers plated,probably black chrome.

[62fatcat]

Cool biuld!
Nice work!

[BruceWilkie]

I like this build!

Try to build a bracket that fully supports the turbo at the exhaust flange to take the weight load off the header pipes. My old turbo corvair the factory had a .125" thick bracket that bolted between the turbine inlet and the head pipe and the bracket attached to the motor. Even after upgrading the turbo the original 1962 head pipes never had any issues.(I had that car till 77) I'm sure the cast log manifolds helped pull some heat out, but with aluminum block and air cooled there had to be considerable expansion/contraction going on. I think I can find a picture of the turbo mount if your interested.

btw currently putting a turbo on the 305 in my 84 GP till I can build a worthy Pontiac motor. Doing it as inexpensive as possible. Even making my own flanges(3/8 plate and remains of an old set of 1.625 pontiac headers). I'm using whatever I can scrounge cheap or free. (plasma cutter tips are pricey for what they are I've burnt up two so far). I decided a rochester 2jet from my old 68 Catalina will be adequate for the 305. Surprisingly finding a large base sbc 2 barrel intake wasnt easy but I did get it near free. I might get this whole project done under $500 including the turbo I bought.

Best of luck with yours, its certainly a lot nicer.

[jdw_poncho]

Originally Posted by BruceWilkie

I like this build!

Try to build a bracket that fully supports the turbo at the exhaust flange to take the weight load off the header pipes. My old turbo corvair the factory had a .125" thick bracket that bolted between the turbine inlet and the head pipe and the bracket attached to the motor. Even after upgrading the turbo the original 1962 head pipes never had any issues.(I had that car till 77) I'm sure the cast log manifolds helped pull some heat out, but with aluminum block and air cooled there had to be considerable expansion/contraction going on. I think I can find a picture of the turbo mount if your interested.

btw currently putting a turbo on the 305 in my 84 GP till I can build a worthy Pontiac motor. Doing it as inexpensive as possible. Even making my own flanges(3/8 plate and remains of an old set of 1.625 pontiac headers). I'm using whatever I can scrounge cheap or free. (plasma cutter tips are pricey for what they are I've burnt up two so far). I decided a rochester 2jet from my old 68 Catalina will be adequate for the 305. Surprisingly finding a large base sbc 2 barrel intake wasnt easy but I did get it near free. I might get this whole project done under $500 including the turbo I bought.

Best of luck with yours, its certainly a lot nicer.

Thanks, Its a big project to tackle by myself. I have a bracket made to attach the collector flange to my j-bar. It lands about 2" from it, so that should stiffen it up a lot.

I ended up milling out my collector flange and had a water jet cut out my header flanges. Using a plasma makes it tear up end mills so I wasted my time cutting one out. I'll have the water jet guys cut them my stainless flanges out next time.

Good luck on your project.

[BruceWilkie]

If you are frame mounting the turbo you may want a flex joint in the exhaust to keep "piping" forces from ruining the turbo(s).

I used up a grinding wheel cleaning up the plasma cuts on the outer edges of all my flanges, and had to sharpen my die grinder bits a few times truing up the centers. Wish I had easy (cheap) access to laser or water jet. I should have used my cut off wheel on the square flange for the turbo mount. I'didnt even want to attempt using a hole saw for the centers.

[jdw_poncho]

Finally more progress on the car. All of my engine parts have been purchased and machining is done. Long block will go together this weekend and I just started on a 25.5 C/M cage last weekend. I expect the cage to take another couple weeks only being able to work a couple hours a night.

Hope to have the engine to a dyno at the end of Feb, already set the date so I better hit it. Lets hope I can get to my goal. I should post some video of the dyno pulls after I have it lined out. I'm seriously thinking of starting over on the headers and building them from stainless. I'll probably start with the mild steel headers for the dyno runs just to gain me some time. Hope to have it ready for some test hits in April or May. Need to run 4.90's to be competitive in the class I'll run.

I have all the tubes cut and coped from the main hoop and back. Just need to get them welded in, but I think I've decided to lift the body off the frame one more time so I can finish welding it. Trying to fully TIG weld all those tubes in is a pain. I need to be about a 100lbs lighter to fit back there!

[BruceWilkie]

Its coming along nice! Did you go stainless on the headers or still with the mild steel? What size injectors did you go with? Looking forward to your dyno report. No doubt you can make the hp you need for your goal, putting it down will be the hard part. What about transmission and rear gears?



This stuff always takes more time than it should. A few set backs on my project so I've skipped wasting time with the 305 project and putting my resources into my Pontiac motor (Last April I finally retrieved my Pontiac block and a few sets of heads from storage in NY). Took 8 months to get rid of all my BB ford stuff without giving it away. I'm not going to jinx myself and set a completion date.

[jdw_poncho]

I'm going to start out with the mild steel headers. I plan to build another set from stainless. Learned a lot over the past few months on how I can improve my clearance. Right now the main goal is to get the engine to the dyno and the chassis certified.

I have two sets of 160's, hopefully I can keep a clean idle. Thats a lot of fuel dumping out at 80psi. But the belt drive pump should help keep pressures down at idle.

I think I'm about 3 months behind, life tends to do that sometimes. I had a problem that needed my attention so I had to drop the project for a little while. Hopefully I can still hit my goal. I cant believe the amount of detail work that goes into building a car like this. I can work on the car for 3 days and sometimes it tough to see the progress.

[greggutknecht]

I know how you feel,when i did my chassis it took quite a few months to finish working on my headers now also but not dealing with turbos.Why the 25.3 and not 25.5.