Twin Turbo project started
 

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.

Neat stuff. Very neat stuff.

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

Nice build. Glad to see another turbo Poncho!

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?

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

What are you putting this in?

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 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 -

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


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.

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.

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.

Cool biuld!
Nice work!

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.

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.

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!

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.

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.

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.

I started to with a 25.3 chassis because I didnt read the SFI website very well. I also had a chassis guy explain to me that I cant use 2" X 3" tubing for any structual support in a 25.3 cage. I didnt see that in the 25.3 bokk but it does state only round tubing can be used. So I bought the 25.5 book from SFI and started with the 25.5 cage.

It seems like everything I do I have to twice. Hopefully the chassis goes together better than the rest of the car. I think I have enough parts to build two cars with all the mistakes or changes I have made.

Its alot of work when you dont do it for a living but its nice to be able to say you built it.Hoping to run some low 8s on the spray when mines done.How far are you from eddyville i mite go there to get my license this summer.

I'm about 3 hours from Eddyville. Thats where I was planning to take the car for my license runs as well unless we get our new track down here by Eiola, MO. I'll need my car to run 4.80's-5's to be competitive at the tracks I was looking run.

I will be at Eddyville running their Modified Index class and possible their 10.5 heads up class this year. Maybe I will see you there.

I hope I can run in their heads up class. But I dont think they will let me since my car has been backhalved. When I looked at the rules they stae I must have a stock rear frame rail so I may only be able to come up there and run test/tune nights.

I would like to see your car at eddyville as well.

As far as I know you as long as it is a ladder bar set up and not a 4 link. Either way it would be good to meet you and see that beast run!

I know I will make it up there this year. Had a setback on the rings and just recieved my second set today. Sent a drawing and pictures to Moroso for a oil pan but there saying 6 weeks. :eek:

I have a old oil pan I can use to get started. Hopefully this weekend I can get the motor done so I can get the pushrods ordered. Next is final porting of the manifold, I left it rough because I wasnt for sure which head gasket I would end up with. Hopefully they show up this week as well.

I can wait to see this on the dyno. Hopefully I'll have a big enough pair to handle that kind of power. I know its more work to get tuned but I plan on starting soft then turn it up after I'm comfortable with the car.

As an FYI - make sure the waste gate is on the outside of the collector bend - or else it wil not work very well - it is something a lot of guys miss on - -good luck

Yeah didnt really understand this until after I built the headers. I've seen a few built the way I have them and decided to leave it for now. I plan on building them out of stainless anyway so I'm gonna try the mild steel set first.

Motor is built but I'm still waiting on Moroso for the oil pan. 4-5 weeks turned into 8-9 weeks. I held off on buying the PG until Feb so I'm waiting for it to be built as well. Hopefully I'll have everything for the dyno by the end of March.

Here is a pic of what I did for the waste gate. I was concerned about the flow path when they were built. I should have listened to my gut before I continued. But its tough getting them to fit within a stock chassis.

This is how I should have built them. Not sure where I stole this photo from but I think its from a stock chassis even though its the wrong flavor.

I know where.

2nd gen Camaro Nelson racing HotRod magazines "F-Bomb"!

Chevy or not that engine is bad azz. My Pontiac will be similar but going in a G body(84 GP) I keep running out of money! Half tempted to put one of my turbos on the 305 for now.

While you wait it might give time to swap sides on the waste gates. I'm thinking of mounting a pair on a balance tube between collectors. Will see when I get there.

Looking good so far. What i noticed after I finished and looked at the fab, how different I would do a few things. So that will come and go, no big deal.
Upgrading my fuel system as we speak as it is lacking, so look into that as well.

It never fails, everytime I build something it takes me 3 times. I expect to build the headers at least one more time. I know what I want to do with the stainless headers that will help with the waste gate.

I just got my Pro-EV hat this week. Holy crap that thing looks big! I might have my cold side put back together this weekend and will take some pics.


I'm using the biggest belt driven pump Weldon has so it better be big enough!

FINALLY making progess on the car. Works been keeping me busy and waiting on parts slowed me down.

Got the cold side about 75% done, still need to weld the BOV's and get the PS turbo attached to the tubing. This weekend I was able to get my V-bands welded to the housings and machine and weld the 3" - 4" transition to it. I tried making a cone from 3" tubing but after a couple tries I decided to just machine one. It turned out a lot better than trying to build a buck from wood and press the 3" tubing into a cone.

Next I need to weld a ring I machined out, to go from my 4" tubes into the 5" EV hat. I couldnt find a silicone coupler I liked so I made the ring big enough so I can use a straight 5" coupler. I bought a V-band to weld on the EV hat but decided I wanted a little more flexibility and will use a silicone coupler instead.

I didnt put all the gaskets in when I was mocking everything up. I decided to leave the passenger side unfinshed until I get my engine in the car. I'm pretty sure everything will grow farther than I expected when I get the new motor in.

Moroso didnt clearance my new pan enough to clear my mains. So if anyone has a new IA2 sitting around they could use a set of mains for measurements. Maybe it will be back in a week or so and I can finish putting the motor together.

This old turd is finally starting to look like something. After taking everything on and off for what seemed like 1000 times, I finally was able to bolt everything together.

Just a few more parts to install- BOV mounts, Throttle cable mount, fuel cell/rad mount and its ready to bump over. The setbacks to building something like this by yourself is mind boggling. I didnt expect that everything I bought would need changed or bought a second time. I had a few costly mistakes.

Unfortunately I'll miss norwalk to make a few passes. The trans I bought wasnt what I was expecting and I havent ordered a converter yet. Not sure how soon a tech guy could come in to get the cage signed off either.

I beginning to think I'll miss the season unless I drive south. I need a couple crew members!! LOL

Well if ya head south this way some, I can help crew. It always seems the longest when you start getting near the end of a build. Hang in there you may get done sooner than you think. Its looking good.

I'm starting to think in years vs months on mine. If it was my wifes car she would have had me finish it 2 years ago!

Looks really good.

My advice is to put a shield protecting the oil lines and filter from debris, or in my case a belt shredding and damaging the line. Happily the stainless steel held up and I didn't have other issues at the stripe.

She finally runs!! I started it up last weekend without the turbos to make sure the wiring is correct. It rolled over a couple times and fired right up like a brand new car. I left the second set of injectors unplugged and started it with VP's M-5. ($8/gallon= ouch!). The fumes about made me puke within 30 seconds of it starting. I had both doors open and a fan running and it still filled the garage enough to burn my eyes and throat. Guess its running a little fat huh?

I laid all the wiring out on the firewall knowing it would all come back out for the trip to the dyno. I started getting everything back on this weekend to work out the water pump/rad mounts. After thats worked out I'll start playing with the fuel tables so I cant get the second set of injectors plugged in.

A word to the wise.... NEVER wire the switched wire from both the MSD and the ECU together on the same toggle. I did it just to start the engine, but when I turned the toggle switch off the engine stayed running. The MSD had enough charge to feed voltage to keep the ecu working. No big deal, I seen what was going on and decided to just pull the ground cable off and......... I wont tell you what happened next. The motor will run roughly 30 seconds when its wired this way. Believe me, you can feel the amps every time it fires the coil.

Remember- Safety first!!!

I made a cover for the belt, thanks for the advice.

Nice build, can't wait to see some dyno numbers!

Good to see progress.

BTW a diode will prevent feedback. My Accel box was getting feed via the altenator and kept motor running even though voltage dropped to 3 volts. I had originally used a relay figuring that would kill power to ignition and pump and the feed back was sufficient to keep it energized as well. Cut the switch... motor "coughed" and "switched back on. I unplugged power feed from fuse. Tried just a switch and thats when I found I had feedback.

For the test run without a alternator, I wasnt expecting to get that much feedback from the ignition box. When you dont want the motor running, 30 seconds seems like a lifetime. I'll just keep the wires seprated by a toggle switch for now.

build
 

very nice looking set up so far. Look foward to more pics as you go. Toying with idea of doing twin turbos on my 77 T/A.

your car looks awesome! Greet work!

Thanks guys. Progess has slowed down as work picked up. I think I finally have this weekend off so I can make some progress with the cage. I havent touched it in 5 weeks and its starting to show.

After being up 30 hours straight we got the engine dyno'd. Made some big power but had a few problems. Spend at least half the dyno session getting the engine wired and hooked up. Next time I go I'll have a better understanding what is needed to help save the time.

They spent some time trying get the FAST system tuned and capable of running the engine on methanol. Then started making pulls while trying to keep it fat enough. It seemed like he was constatly adding fuel and it would make more power.

We proved that a vacuum pump will not work on this engine. I seen people run their engines with it and without vac pumps so I decided to try it. It pushed oil out anywhere it could.

Finally made a few strong pulls. From the picture you can see it was making good power but we couldnt control the boost. They told me my exhuast housing are way to small and the waste gates didnt work very well.

It was blowing exhaust out the gate it just seemed like we couldnt get enough out to control it. This was the best run in all, then the bad stuff started happening. Next pull power was down about 100hp at the same 4500rpm. We stopped and pulled the plugs looked over the data and realized the fuel pressure was jumping around a little bit. After checking that out we decided to make another pull. This time the upper hose blew off and sprayed water every where at around 5400rpm. Hopefully its just a head gasket failure. But it ended my day with only 2 hours left in my dyno session. I brought a gasket but I didnt think I could get it done that quickly.

EGT's were staying good all day and never got above 1080 degrees. The last run we were worried about watching the fuel pressure and both of missed the egt's going over 1300 degrees. But it happened so fast that most likely I still would have had damage.

After getting some sleep today I'm starting to pull the motor down. All I know is I'll have to sell these turbo's and step up to a mid-size frame or a big single.

But you have to admit 1500ft/lbs of torque at 4400rpm's would make a hell of a street engine for someone if they wanted to buy the turbo's.

What we figured happened was the injectors were losing their signal or quit driving because the fuel pressure was jumping from 73lbs up to 100lbs within a few rpm's. Thats where the 1300 egt's came from on the last run.

Sorry to hear the bead news.

On the Vac pump...Did Morris comment on the need for one? It has been a debate amongst the turbo guys for a long time. It has worked for me so far but with relatively low levels of boost.

What size Turbos are recomended now? I would think 88-91 range. My 106 seems like a good fit for the 535 so far.

Nice low RPM HP\TQ number there. What size cam do you have in your 512 IAII?