boosted LT1

iTrader: (3)

I have a rear mounted LT1 with an Ebay T70...yes the turbo is junk worked but runs out of breath...

I want to change the turbo and think I will buy a Master Power T70 either divided T3 .70 or undivided .96

The primary reason for the choices is I have a T3 currenly with 3" V clamp so it should drop in.

My other choiced I think is the T64

My current turbo is a T70 with .84 turbine and the boost comes in good my goal is < 500 RWHP the car weighs 4400 with driver

I have lurked for a year or 2 and finally registered today to try and get help before I make another turbo mistake.

Thanks for any help.

boosted LT1

iTrader: (3)

LT1 iron heads, stock valves and cam, ceramic coated manifolds, 52 mm tb, 2.98 gears. The piston are forged probe ~8.5:1 and boost controller is set !16 psi.

The stall is ~2000 brake torque, 4l60E has done 13.1 with 2.2 60 ft on steet tires. MPH ws 112

I think that is all the pertenent information that all will want to know

qqwqeqwrqwqtq

So this is a caprice/impala? I'm not expert on rear mount systems but I would think that a T3 flange would choke this setup regardless.

boosted LT1

iTrader: (3)

It's a Buick Roadmaster. If I were starting over I would definately make it a T4 but it was built 2 years ago and I prefer to not redo the exhaust. T3 won't flow high HP but since my goal is <500 RWHP I am hoping the T3 T64/T70 will flow enough for the setup. My RPM with stock cam is low since I have all the weight and bad gears I shift ~5400 which should help the T3 survive in the setup.

As big as this car is there really isn't alot of room to fit a turbo under it.

Thanks for iresponse does the T3 still seems too small with the additional information?

import_eater

sell me the kit! lol

boosted LT1

iTrader: (3)

hahahaha actually this is the second version so I did have one I could have sold. It is 2.5" from manifolds into a single 3" to the turbo. It has a small FMIC and methanol so the IAT stay low

It originally had MAF then I changed to SD. I have Datamaster files showing the boost coming in with MAF. It max's F body MAF I think <4000 and as low as 3500 with ceramic coated manifolds.

qqwqeqwrqwqtq

Well, yes. Even considering rear mount, 500rwhp and 5400 shift point, 5.7L through a single T3 turbo seems like it would be terribly restrictive IMO. (and your report of "running out of breath" concurs).

What do you currently have for a turbine wheel?

At this point I think switching to a single T4 should be fairly easy and a worthwhile upgrade.

boosted LT1

iTrader: (3)

I looked on ebay and the closest turbo I found was around 57/74 for the turbine and .84 a/r

If I have to I gues I will have to chnge the connector it is not that easy since like I said there is VERY ittle room and my muffler guy is a pita

But it is also painful to have it wrong.

boosted LT1

iTrader: (3)

I don't understand how the T3 won't flow the hp?

I am not questioning you I am asking to allow me to understand how the size of the flange limits the flow through the turbo.

I mean when I look at a turbo the exit area for the exhaust through the turbine is tiny relative to the flange. I believe what you are saying but I would like to understand why the flange is limiting my hp.

Thanks

XtremeDime

iTrader: (16)

t3 flange is significantly smaller than a t4 flange which would limit the amount of air that enters the turbo, would also create TONS of backpressure on these motors

boosted LT1

iTrader: (3)

I guess it is simply at some point the T3 can't keep the turbo spining and just gives exhaust back pressure.

Ok I am SOLD! I will upgrade to a T4!

Now which turbo? A 64 or 70? And what A/r for turbine? I wil go 3" v clamp since I like the ability o run a muffler and drop it at the track!

XtremeDime

iTrader: (16)

t70 with .96 a/r from Modular Turbo!

boosted LT1

iTrader: (3)

Yes I will DEFINATELY buy from vender here! It is easy when they have what I want and a GREAT price!

They carry 2 turbines .68 and .96 I have to say I am not sold on .96 yet. I like the idea of fast spool of the .68 especially if it wouldn't limit my <500 RWHP goal.

I have made a serious change already though and thanks for both of you preventing me from doing another T3!

I now think that is alot of the boost falling off (hitting 16 then falling to 14 or 13) in second and drive.

Thanks for your help

355TurboLT1

iTrader: (11)

You should totally buy my 76GTS!

DrTurbo

iTrader: (3)

For a rear mount....TC76 all the way.

boosted LT1

iTrader: (3)

My rearmount LT1 is near stock with just forged pistons. It is ~8.5:1, has a 2400 stall that yields ~2000 at launch, stock heads and 191/196 .45/.46 at 111 cam

I like driving the car and want ~450 RWHP it has developed ~400 RWHP at track on street tires with a 2.2 60 feathering it. It will be faster with slicks and I now have a set. I converted it to turbo 2 yrs ago so it is reliable and if I get agressive I think it will lose the care free DD aspect.

I have a drag car a 280Z datsun with twins 400 and 9" so I don't need this car to be a fast car. I am trying to resist the little bit more syndrom but what it is now is not good since it is kinda broke...

I hate a car that is almost right but I also don't want to spend money to make it faster but a car that is always breaking parts