turbo questions

[Anonymous]

well im 18 and wanting to do something a little different then a 289 or 302 in my 66 stang i want to turbo my 200 and i had a couple of questions like how to install gauges for airfuel ratio and boost/vac pressure as well as how to control the boost coming out of my turbo. i would also like to know if does10s can provide me instructions on where to get one of those wonderful turbo manifolds. i also had a question on 73 and later pistons that lower the compression if their good and if it's alright to have cast pistons also with a turbo set up is a 272 list cam is suited for the job as well as a holley 350 who makes good blow thru carbs and what good ignition devices i can use to control boost and acheive hotter sparks

 

[kirkallen143]

Howdy,
1. weld a bung on the exhaust pipe closest to the turbo for an O2 sensor for the air/fuel ratio
2. boost will read directly after the compressor so tap a barbed brass fitting into your intake tubing before the carb.
3. boost is controlled via a wastegate (internally or externally) depends on the turbo you get.
4.Will's exhaust maniflod is homemade.
5. cast pistons are fine even up to 18 lbs of boost and your CR can be controlled via different head gasket thicknesses, plus different dish type pistons.
6. the 272 cam is fine, some have cammed up to 280 list that they are using.
7. the 350 holley is a fine carb to use, take off the choke assembly, mill the choke horn and block the choke rod hole with jb weld, install a solid float and the correct jetting and Power valve and your basically done.
8. ignition goes both ways, and you don't want a hotter spark in case of the turbo...DENOTATION at higher rpms! run a colder plug and can even reduce your gap alittle. you can use a timing retard device like MSD (for electronic ignition), or not use vacuum advance relying on centrifical alone, or use a advance/retard vacuum canister off the dist.
9. don't forget about the BOV to release pressure when coming off the pedal (like shifting)
10. to give more boost you can get a boost controller that limits the pressure going to the wastegate. can make them yourself or buy them.
it is simply an adjustable relief valve that is spring loaded.
11. fuel needs to be boost referenced, also. you can do this to your stock fuel pump by running a boost referenced line to the atmospheric side of the pump (which will raise fuel psi when boost is on) or go electric pump with a boost referenced and return style fuel pressure regulator.
12. your exhaust needs to be free flowing with minimal backpressure (some is good for the low end)
13. and make sure the rest of your drivetrain can handle the turbo.

Hope I did not forget anything and Good Luck!

Kirk ' 73 bronco

 

[Anonymous]

I've always been told in a turbo application backpressure isn't needed. I figured that's why all the new diesels aftermarket pipes are mandrel bent 4in and 5in pipe..... I dunno. Any1 feel like explaining if the backpressure is still needed in a turbo application or not?

 

[XFlow_Fairlane]

the turbine on teh turbo works on a pressure difference between the manifold and the tailpipe. if you put a muffler in there you will increase the tailpipe pressure which reduces the pressure difference. so the key thing to to run a straight through muffler or none. (in IL a turbo counts as a muffler )but on a daily you might want some type of muffler on it. there is nothing wrong with some generic "turbo" mufflers but a straight through header muffler works good too.

 

[Anonymous]

thanks a lot for your guys' help i really appreciate it a lot

 

[Does10s]

I think Kirk answered everything!

I am building turbo headers for Mike (AZCoupe) at www.fordsixparts.com. I'm currently doing it on a one-by-one basis, so it takes some time to finish one up. I'm working on one now for a customer. There's one already out there somewhere.
Later,
Will

 

[kirkallen143]

There is a graph in the turbo book by Hugh Mcginnus (?) that shows with the application of a t-bird thundercoupe with stock exhaust, aftermarket, and an aftermarket with no catalytic converter. Aftermarket strongly improved all areas of HP over stock, where as without a converter vs. with, the converter installed made more HP in the low end, but slightly less in the upper rpm range. The HP difference was more dramatic in the lower rpms with more backpressure, and again only a slight gain in the upper rpms without a converter.

Kirk ' 73 bronco

 

[Anonymous]

Howdy,
1. weld a bung on the exhaust pipe closest to the turbo for an O2 sensor for the air/fuel ratio

Except with a wide band O2.

Heat kills them quicker. Most will agree it is best to have the wideband O2 about 4 feet or so (or even farther) downsteam of the turbo outlet. Narrow band o2's can be closer.

 

[wallaka]

Aaannnddd...it's been pretty well proven that an engine needing backpressure to operate, or make optimum torque is a myth. (Seems like the older a person is, the more they believe that )The reason to not go too big on exhaust size (on naturally aspirated engines) is to keep the exhaust velocity up. That is needed for torque production. On turbo engines, it's pretty much impossible to go too big on exhaust size. I was running 3" on my Honda and had no ill effects at all and gained 20 hp or so on the top. If i could've fit any larger pipe under there, I would have but was kinda running out of clearance around my suspension . 3" was a tight enough fit. Anyways good luck in your experiments and keep us posted!