[Mad Beems]

I'm buying a dart based 345" short block and I'm looking to upgrade my turbo setup. I've got a stock 302 with a master power t70 now that's been 9.80s @ 138 and I've been very happy with it. The new motor will have afr 205s on it and a hydraulic roller. The car is mostly a street car but I would like to run it in our local 275 class and some street car races. I would like to shoot for mid to high 8s in the 1/4 without pushing it too hard.

So my question is would I be better off adding another t70 or switching to a single like an s480 for my money? I've also considered putting a t4 76 on my current setup.

 

[mrvoorhees]

can you find a match for the master power if not i would start over with a new turbo

 

[Mad Beems]

Match in what way? I'm pretty sure its still a readily available turbo?

 

[mrvoorhees]

ok i see for some reasone i was thinking that the company went under but people still have them on the shelf ..... so in that case whats your local rules on turbo cars ...

are twins allowed
also will your curent hot side support more power if you put on a larger turbo got pics of your set up

 

[Mad Beems]

The rules are pretty open ended. Just tires pretty much. The current hot side would have to be modified for a t6 sized turbo. I'll try to get a picture posted.

 

[mrvoorhees]

with those cubes im wodering would a t4 base turbo run a number ..... what i would due is see if you could get a fresh set of t70s and use the one you have for a mock up and also a back up if one of the new ones went down .......if a single im sure you can salvage some of your old hot side to make a t6 work ..... twins will cause you to have to start from scratch and buy 2 of every thing. to me you can make the power you need to from twins or a single........it comes down to how you try to package it under the hood

 

[mrvoorhees]

t4 units
pte pt8847h 0.96 ar
pte 7475 0.81 or 0.91 ar
take a look at the specs for these turbos i found them used on the net may be worth a look

 

[Mad Beems]

This is an old picture, but the turbo kit is still the same basically.

Please ignore the hideous wiring rats nest lol. It is no longer there.

1 5/8" headers, 2.5" crossover and a 3" downpipe

 

[Injected65]

Hell of a step up Beems. Congrats. I would think an S480 would be able to be fit to the existing kit without too much trouble/modifying. Then once you start to max it out you can have it changed over to an 88mm version. Twins are nice, but they can be a packaging pain some times.

 

[Mad Beems]

Thanks Chris! I'm looking forward to having a little more reliability in my car and hopefully going fast.

Anyone else got an opinion?

 

[bluchev]

I say twin 70's. That outta get you plenty faster than what you have now

 

[4jenna]

Twin 70s with p-trim wheels can make some serious steam! What housing is on the current one?

 

[Mad Beems]

It has a .96 on it but I also have a .68 sitting on the shelf. I was thinking the .68 will probably be better in a twin configuration so it spools decent.

 

[mrvoorhees]

i think with the small .68s you will have traction issues or wheel standing issues i would like to see you in the 80s for your ar its a 1/4 mile car so you can let the car run out the back door and the mph should be nasty as well if you could 1.35 1.40 60ft game on

 

[mrvoorhees]

few questoins
whats your rear gear and tire size
whats the converter and trans set up
and will you be changing the cam

 

[Mad Beems]

3.27 gear. 275/60/15 dr so 28" Th400 Trans and the converter is a tight art carr. I leave around 3500 rpm with the current setup on the two step. 1.42 60'. The cam is going to be a comp 282hr part # 35-522-8 at first. I know its not very optimal but its all I have to use for the time being.

 

[mrvoorhees]

if it was me i would make your hot side work with a s475 s480..... save the money from going twins and get a cam..... you can run twins or a big single all you want you will be leaving a ton of power on the table ........worst case get some one to spec you a cam and get dough herbert to grind it for you .........they may be a lil off but i think it would be better than the comp ........i think with some time you can make the t6 turbo work..... also think about it you already have parts to work with and you dont have to buy much if you stick with the signle .......

 

[mrvoorhees]

did you have that comp in the 306 if so i wonder how much faster you would have been with a turbo cam

 

[Mad Beems]

the 302 has a custom ground Ed Curtis cam. I don't remember the exact specs but it was something like 228/232 567/576 on a 110 LSA. It was ground for an n/a combination with up to 125 hp of nitrous lol. But I've had it in the car for years and it didn't work out too bad with the turbo. Not bad for a stock short block!

 

[classic boost]

if you stick with a single, you won't have to get a different intercooler (that has two inlets).
also, a single will be legal in more classes.
check out the precision pt8847. it's t4 based and people are running good with it.