turbo setup, help needed.

[85 Cutlass Brougham]

It depends on the twin turbo setup. Some use twin turbos of different sizes with one feeding the other in series, some use two turbos of the same size feeding a common intake in parallel, and some use two turbos of different sized feeding a common intake in parallel. The series setup uses the pressure ratio of the first to pre-compress the air for the second, which then increases it by it's pressure ratio. Remember that ambient air pressure is 14.7psi at sea level, not zero when performing these calculations. The parallel turbos of different sizes use the fast spooling of the smaller turbo at low RPM's, and when it runs out of steam the bigger one is taking over. The Toyota Supra Twin Turbo's 2JZ-GTE comes to mind as a car that is made like that.

 

[pokertramp]

You will need a blow threw carb. probably around $600. With a turbo set-up it would kill the factory foam floats so I think they put neoprene floats in them. I think Blow threw is better than a draw system.

You will probably be better off with one big turbo versus 2 small ones, easier to control boost in my opinion.

Boost pressure regulator, one from Aeromotive would do and a electric fuel pump.

Upgraded ignition, Blow off valve, carb hat which I think pepboys sells or you can custom fabricate one. Wastegate controller, MSD has a nice one.


It has been a while but last summer I was working on a 64 Mustang with an Inline six. I was working on a turbo set-up for it but I was diagnosed with cancer and I never got to do it. Another guy did it on a inline 6 totally stock with over 200,000 miles and cost him less than $1,000 I think.

Do your research and anything can be done, just make sure you have fun doing it. 8.5-1 compression is perfect for a turbo setup but if the motor blows, rebuild it. If your afraid then don't do it.

 

[midwestls]

I wanna see turbo powered G's!!!! (besides just GN's and T's)

 

[85 Cutlass Brougham]

Rather than a turbo setup, a centrifugal supercharger would probably be easier to do. You would still need a carburetor designed to take boost, and an ignition control box that will boost reference the timing curve, but the plumbing is much simpler. If you are experienced at fabrication enough, the turbo setup could be done cheaper.

One idea for the fuel system would be to run a TPI manifold with larger injectors then run the engine management off of a Megasquirt II kit. Use the fuel tank and pump from a Turbo Regal, and run your own fuel lines, etc. Megasquirt is nice for a GM because t was originally designed with common 1980's/90's GM sensor values in mind. it is speed density, but many people have successfully run them on boosted applications. It could probably be done cheaper than a boost carb and ignition retard box, but you would still want a hotter spark because the boost pressure tends to snuff out the flame front in the chamber.

For a Turbo, you could probably get another T-3 cheaper than a single T-78. T-3's were sort of the default turbo used in many 80's and early 90's turbo cars, so they are easy to find. However, just because it is a T-3 does not mean it is the same as the T-3 you currently have. The A/R (area ratio) is usually tweaked by application, so each one boosts a little differently. If you run them into a common plenum ( like a GM TPI) this should not be a big deal.

Turbo setups get a little complicated because they take up a lot of space and they generate heat. You need to minimize the amount of piping to limit lag, but you still need to find space for a fair amount of it. However, the compressed side of things can be smaller than you think because the air is compressed. So, you may only need to use 2 inch piping for everything out of each turbo and into the intake. Don't underestimate the need for heat shielding too. If you do, it will melt or destroy components because turbos run hotter than headers. This is because they do add a bit of backpressure, and if you remember the Ideal Gas Law, you know that when you pressurize a gas it heats up.

There is more, like optimizing your camshaft choice for boost, but I am out of time. I gotta get ready to go deliver the pizzas!

 

[TurboKyle]

ok, im going to be enrolled in an automotive engineering program at a local state university in the fall, and i am looking to get a little experience, and have a little fun. im looking into building a turbo setup for my 400. i have the front mount and a t3 garret turbo. i know the basic function of the turbo and how it works, but can i do it to my car? i was thinking if i modify the headers by running four seperate pipes off of each exhaust port into one pipe, which will lead to the turbo, then from the turbo to the fmi and then duct that pipe into a blow through carb. sounds simple enough, and thats why im nervous, i know the fabrication and tuning will be the most difficult, but other than a wastegate am i missing anything? can i run it off of only one header, i only want a single turbo, they are more efficient anyway. any suggestions are greatly appreciated. this looks like it might be my next winter project. im not looking for major boost nor am i looking for 4 digit horsepower (yet). i want to get the functionality issue sorted and then unleash the crazy!!!

I Just want to clear up a few things. First a T3 garret turbo generally refers to the foot print of turbo, I.E. T3, T4, and then the Twin scroll varieties of both of those two. Second a T3 can come in a verities of sizes some of the diesels turbos come factory in a T3 format So size might not be an issue. I'd take off the compressor and then measure the compressor wheel and you might have a better chance of figuring out exactly what you have. Third a single turbo setup isn't necessarily more efficient then a twin turbo setup. It all matters on the size and the intended operating pressures of the turbo setup. And I would definitely use both banks of exhaust because the increase in back pressure on just one side would be bad for your engine but if you just run a crossover pipe from the other bank under the engine you should be able to equalize the pressure on both sides of the exhaust banks. And whether or not a supercharger would be easier or better all depends on your type of driving your planing on, a turbo typically lends more power to in the higher RPM range where a supercharger usually gives you a larger boost in the lower RPM range because the SC Pulley takes a large amount of power in the upper RPM range.

 

[TurboKyle]

Rather than a turbo setup, a centrifugal supercharger would probably be easier to do. You would still need a carburetor designed to take boost, and an ignition control box that will boost reference the timing curve, but the plumbing is much simpler. If you are experienced at fabrication enough, the turbo setup could be done cheaper.

One idea for the fuel system would be to run a TPI manifold with larger injectors then run the engine management off of a Megasquirt II kit. Use the fuel tank and pump from a Turbo Regal, and run your own fuel lines, etc. Megasquirt is nice for a GM because t was originally designed with common 1980's/90's GM sensor values in mind. it is speed density, but many people have successfully run them on boosted applications. It could probably be done cheaper than a boost carb and ignition retard box, but you would still want a hotter spark because the boost pressure tends to snuff out the flame front in the chamber.

For a Turbo, you could probably get another T-3 cheaper than a single T-78. T-3's were sort of the default turbo used in many 80's and early 90's turbo cars, so they are easy to find. However, just because it is a T-3 does not mean it is the same as the T-3 you currently have. The A/R (area ratio) is usually tweaked by application, so each one boosts a little differently. If you run them into a common plenum ( like a GM TPI) this should not be a big deal.

Turbo setups get a little complicated because they take up a lot of space and they generate heat. You need to minimize the amount of piping to limit lag, but you still need to find space for a fair amount of it. However, the compressed side of things can be smaller than you think because the air is compressed. So, you may only need to use 2 inch piping for everything out of each turbo and into the intake. Don't underestimate the need for heat shielding too. If you do, it will melt or destroy components because turbos run hotter than headers. This is because they do add a bit of backpressure, and if you remember the Ideal Gas Law, you know that when you pressurize a gas it heats up.

There is more, like optimizing your camshaft choice for boost, but I am out of time. I gotta get ready to go deliver the pizzas!

I've been lurking this forum for a long time and I know that you like to think and a lot of your Ideas are great but I have some suggestions on some of these ones. If you ever get the chance read "maximum Boost" by Kenny bell It’s a great book that goes into details about Turbo setups he’s a little obsessed with Porcse but still a good book. A couple thing first off your 100% right the piping is a nightmare on Turbo Setups, But depending on the size of the turbo really will have more effect on turbo lag then your piping size. Look at STS Muffler turbos for examples of how pipe size doesn't effect today’s turbos as much as they used to. And the heat thing is something that you have to deal with no matter what power adder you use, but look up a company called Snow performance and their Meth injection, race gas boost on pump gas. And I wouldn't shrink the piping any smaller then the outlets on your compressor because even if it is compressed the smaller pipe cause a restriction which will limit the flow of air you get per pound of boost. Remember its not the boost that matters it's the LBS of air you get per pounds of boost that makes you car fast. A free flowing intake track allows you to get more LBS of air with less boost which should make avoiding detonation much easier. And heat shield everything on the hot side the cold side should be ok provided that your Front mount Intercooler (FMIC) removed enough heat. I’m sure I’ll add more if after I get a few minutes to think more.

This kit would be a good start, I wouldn't trust the Turbos, but you get the idea of all the stuff thats would be needed just to hang the turbos, piping, and intercooler Turbo Kit

 

[ryanelco]

I understand this is not a project just to jump into, and that i have to research the hell out of it. Thanks for the suggestion on the book, i just ordered another called "turbos" by jay k. miller. supposed to have a lot of hard to find compressor maps for different turbos. i also have a junk small block on a stand i will build and fabricate the setup on and possibly test on first, but im not sure, i intend to first get the new motor transmission and rear combo running and dialed in, and then undertake the turbo setup. I know this may not be the most cost effective way of forced induction, but to pop the hood and be able to say i built it myself is really what im aiming for, im expecting to break a lot of stuff, but its not my daily driver, so its not a big deal. Like i have said in the past, any opinions and any advice is greatly appreciated. I just want to see the look on the faces of srt-4 or evo owner when they see the front of my car with the fmic staring them down, it always looks menacing to me, especially on an old car where it doesnt belong!

 

[megaladon6]

you may want to go over to http://www.pro-touring.com/forum/ as there's a wealth of info from people who've home built their turbo setups.

 

[85 Cutlass Brougham]

My point was not to make the piping too large. Sizing it to the outlet would be a great idea, but no larger. Also, the turbo referenced was a T-3, which is not a modern design like a Garret GT series. I am by no means a turbo expert. I have never even owned a car with a turbo on it. I just have read up on the subject extensively and was sharing what I know. Sadly, now that Sport Compact Car magazine is dead, I have lost my best source for theory. (If you have never read it, it was the most technical car magazine I have ever seen. Plenty of math, and practical theory with none of the rice.) Anyhow, there is a huge difference between the needs of small and large displacement engines with turbos. Larger engines like we have do not have as much of a lag issue because of more low end torque, and a greater volume of exhaust gases to spool the turbine. Small engines like those in a Civic are more sensitive though because they lack the exhaust volume for spooling. I will also add that there is a certain amount of parasitic loss with a turbo too. It is less than with a belt driven compressor, but it still exists due to extra backpressure. There is never a free lunch, the laws of thermodynamics make sure of this.

 

[TurboKyle]

My point was not to make the piping too large. Sizing it to the outlet would be a great idea, but no larger. Also, the turbo referenced was a T-3, which is not a modern design like a Garret GT series. I am by no means a turbo expert. I have never even owned a car with a turbo on it. I just have read up on the subject extensively and was sharing what I know. Sadly, now that Sport Compact Car magazine is dead, I have lost my best source for theory. (If you have never read it, it was the most technical car magazine I have ever seen. Plenty of math, and practical theory with none of the rice.) Anyhow, there is a huge difference between the needs of small and large displacement engines with turbos. Larger engines like we have do not have as much of a lag issue because of more low end torque, and a greater volume of exhaust gases to spool the turbine. Small engines like those in a Civic are more sensitive though because they lack the exhaust volume for spooling. I will also add that there is a certain amount of parasitic loss with a turbo too. It is less than with a belt driven compressor, but it still exists due to extra backpressure. There is never a free lunch, the laws of thermodynamics make sure of this.

Your 100% right on having your cake and eating it too. But I was just saying try to find the middle ground on the piping size. One thing I want to point out so no one gets confused is that a Garett T3 or T4 Usually refers to the exhaust housing on the turbo. And even new Garett GT turbo's comes in this house. The new Garett GT turbos are all new ball bearing CHRA or the guts of the turbo along with newly designed wheels, but the outside looks pretty much the same on some. And to the OP take a look at your local libary thats were I found my copy and the technical info of the comprosser maps is great but make sure the system is 100% first. I.E the location of the wastegate, blow off valve/valves, and hell even if you want either of those to recirculated or open.