So I am in the planning stages of another build. The ultimate goal would be to drive to the track run a low 9 - high 8 sec pass and drive back home, this will be a streetable car.

I like the fact that twins would spool quicker and have the same top end pull. Its also easier for me to place twins in the engine bay. The simplicity of a large single turbo seems like a plus but it will be a pain to find room for some 100+ mm turbo. What else does a large single have going for it?


This is going into a 84 regal with 11,600 miles on the body. Fully built LSx block @ approx 427 cubes, 4l80E trans, 9" ford rear.

 

I don't think that you'll have much problem fitting any of those options in the engine bay. Having said that if you want streetability then I would go with twins. I don't really see any advantages of a large single other than weight (maybe.)

 

There is plenty of room in a G-body engine bay for whatever you want. I've seen a 632ci Merlin block with a huge single turbo... and there was still room to spare!

 

i wanna see if anyone else chimes into this, im kinda interested as to what the pro's and con's of each set up are as well.

 

Since this is going to be a street car it would seem to me that it would be much easier to run dual 3.5" pipes out of the engine compartment to the back then a single 5" pipe. These would give you about the same exhaust flow area/cross section.

I'm not sure what kind of muffler you would run with a 5" pipe either.

 

5" muffler - bullett, vibrant race, magnaflow, im sure theres more

witha 5" you can split the 5" pipe into two 3" sections and run them out

 

If twins spool quicker and have the same top end pull, it sounds to me like they are the better option. However, for a race setup, I've never heard of two smaller turbos being able to spool faster and pull on the top end as well. It's always been a give and take. The twins spooled faster and gave more low end grunt while sacraficing top end pull. Meanwhile, a large single is just the opposite. Hence the reason ti is used for drag racing a road course cars go with twins or a smaller single. What am I getting wrong?

 

also, consider....you can spool a large turbo just fine on a trans brake, and if you cant get it to start spooling, you can also spray the car to get the turbo to spool.

since this is a drag car, im assuming you are using an automatic and will not have to worry about re-spooling everytime you shift

 

I always thought that the big drag cars always used one turbo because the compition rules limit them to one power adder and having a twin turbo violates that. But I could be wrong, just a random thought.

 

yes alot of comps with outlaw certian sizes, Like some classes have to u a max of 80mm etc. I looked at pump gas drags i think it was and they outlawed anything bigger then a T4 turbo! i found that rediculous! It was either pump gas or LTX shootout cant remember.

I kinda wish I went twins bc its a street car, a T6 is hard to fit.

BUT an 84 regal has tons of room, ive seen a PT106 shoved in with minor hacking.


Jay

 

Yes the car will be used for drag racing and will have an auto trans. It will be a street car and i dont want to have to hack it up tooo bad. Im still unsure about that whole twins will spool faster and have the same top end busniess.

 

anyone have pics of a pt106 in an engine bay?

 

head to theturboforums.com several over there have pt106's

that or on yellowbullet.com

also with twins, you have twice as much piping, two wastegates, etc, costs go up VERY quickly

what are your goals for the car that you NEED a 106?

 

Seriously. For low 9's/high 8's, you could actually go with a small 76mm turbo. Anything over that will have capability to go faster than the stated goals.

 

i was just going to recommend a s475, should get him to his goals.....if not a s488 for sure would