Turbo for 455+ cubes

[BigBlockOlds]

This isn't exactly Buick related but figured I would ask the turbo experts from the GM G-body line about this. LOL

I'm looking into the very early stages of putting together a plan for adding a turbo to the 455 Olds engine I have in my '87 Cutlass.

My question is what size turbo would be adequate to feed a 455?

I'm just looking into something in the 500hp+ range right now. I could do it naturally aspirated with the 455 but I believe using a turbo, I can keep the street manners pretty tame which is a huge goal of mine.

I don't neccessarily want and engine thats going to let the person next to me know what it is.
Thanks for the help,

 

[Grandnat]

PT 54


will easily make 500 hp , would spool insanely fast with your cubes and can be turned up to make more 550 rwhp pretty easily.

also they are one of the cheapest turbos that precision sells.

I got mine for $675

they are by far the best bang for the buck

and they will get a G body into the 10s with ease.

 

[Marc87GN]

Originally posted by BigBlockOlds
This isn't exactly Buick related but figured I would ask the turbo experts from the GM G-body line about this. LOL

I'm looking into the very early stages of putting together a plan for adding a turbo to the 455 Olds engine I have in my '87 Cutlass.

My question is what size turbo would be adequate to feed a 455?

I'm just looking into something in the 500hp+ range right now. I could do it naturally aspirated with the 455 but I believe using a turbo, I can keep the street manners pretty tame which is a huge goal of mine.

I don't neccessarily want and engine thats going to let the person next to me know what it is.
Thanks for the help,

I wouldn't go smaller than a T-76. I had one for 3 years on my 99 GT that was only 281 ci and it spooled by 3200 rpms and made almost 460 rwhp & over 550 rwtq at 12-13 psi. It was very streetable, 20 mpg and I drove to every event from NY to Florida.

You could make ridiculous hp & torque on pump gas barely spinning the turbo. 3 years later and the T-76 I had when I sold the car had Zero play. Why deal with a smaller less efficient turbo when that V8 will spool a big shaft like nothing.

 

[madhat]

hey grandnat, just how fast would a pt54 spool on his 455?

 

[Grandnat]

Originally posted by madhat
hey grandnat, just how fast would a pt54 spool on his 455?

probably too fast... if there is such a thing

 

[BOOSTBROTHER]

Me and a buddy have been looking putting twin stock GN turbos on his 468ci buick, we are both upgrading in the spring and then we would have the turbos for it.

 

[BigBlockOlds]

Thanks for the info. It definitely gives me an idea where I need to start looking.

The biggest problem I'll face is block integrety if I go much beyond 650hp.

I figure a streetable 500-550hp engine would move the Cutlass pretty good.

One other question. What are the opinions on cast iron manifolds vs. headers for a turbo application?

I've read somewhere that cast iron manifolds will seal better long term than a header setup due to the weight of the turbo.
The idea I had was to use two standard run of the mill exhaust manifolds and modify the passenger side to except the turbo by welding the proper flange onto it and flipping (the manifold) front to back.
For the drivers side manifold I would just run the standard stock manifold with a crossover pipe under the oil pan and back up to the passenger manifold.

Or would I be better of making a custom set of stainless steel headers?

And one more question. I believe I've read of aftermarket intercoolers for the Buick's that are made to be placed in front of the radiator as opposed to the stock location behind the radiator.
If so, will these intercoolers basically bolt up to any G-body car?

Thanks for the help!

 

[sixgun86gn]

You would be out of the efficiency range of a 54 or even a 76 too fast with a 455.Takes ALOT of turbo to make decent boost on cubes like that.I would suggest no smaller than an 88 seriously.

 

[CTX-SLPR]

I'd suggest going to www.turbofast.com.au and using thier turbo calculator. That should give you a good idea of where to start, though I would say that you're lucky olds 455 don't like to spin very fast otherwise you'd probably stuck with massive lag on the bottom end if you got a turbo big enough to suport the upper end of the rpm range. What's your purpose for doing this, sick street car, all out racer, dual use...? Unless you're doing all out race modifying the stock manifolds is probably your best bet, stainless is expensive and mildsteel doesn't stand up to the thermal variation of turbocharging very well unless you coat it inside and out. Also you going blow through carb or EFI setup? Thought about intercoolers? What about twins because looking at turbofast, they don't want you running anything more than 8psi with a single turbo though I don't think they count stuff like the thumpers in thier calculations. Twins are also much easier to lay out in a custom setup on a V engine. If you really want to go nuts on a single get a Ford Powerstroke turbo, its designed to work with a 7.5L diesel so it should work well with yours.

Just some food for thought,

 

[BigBlockOlds]

Originally posted by CTX-SLPR
I'd suggest going to www.turbofast.com.au and using thier turbo calculator. That should give you a good idea of where to start, though I would say that you're lucky olds 455 don't like to spin very fast otherwise you'd probably stuck with massive lag on the bottom end if you got a turbo big enough to suport the upper end of the rpm range.

Yeah I was referred to that site by a friend and have been checking it out.
I don't plan on spinning the 455 much faster than 6000rpm because like you said, they make most of their power down low.
A question I have is when using this calculator I type in the following information:

Gasoline engine
7600cc
6000rpm max
Intercooler? YES
Turbo Boost 6lbs

Like you said, this shows that 6lbs is as high as I can go before I need two turbos. But, it shows at the bottom that the BHP is 722.5. I'm assuming that is the Brake Horsepower that this turbo should help produce on an engine of this size.
It just doesn't seem that 6lbs would make that kind of power when you hear of a lot of people running 15+lbs and maybe getting up to that power level.
But, most of the ones I've seen who run the higher boost also have smaller displacement engines. Does the larger displacement play that big of a role in the power production?

What's your purpose for doing this, sick street car, all out racer, dual use...?

My purpose is a multitude of things. The car in general uses to be my daily driver through high school and college. I swapped the 455 in about midway through college and continued driving it everyday. It was my first engine buildup and to be honest, hasn't performed as well as I would have hoped. I also in my haste ripped out a lot of the creature comforts that it once had. A/C, cruise control, etc. I've lost a lot of the driveablity for not much gain in performance.
Now that I am out of college I've turned my attention to fixing the body rust and getting the car to semi-show quality, redoing the engine setup, and this time around, adding all of the creature comforts that I deleted years ago. It will have A/C, cruise, a nice audio system, better manners in driveablity, but at the same time, producing tremendous power.
I'd like something that would at least be in the 12's if not knocking on the 11's without going to a drag suspension setup.
It'll be setup to cruise, road race, etc. You could say its going to be a jack of all trades and a master of none. LOL

Also you going blow through carb or EFI setup?

I'll be doing an EFI conversion on it using either a Tunnel ram base and a custom air plenum with a front mounted throttle body (like the Corvette's, F-body's, etc) or, I'll use an Offenhauser Port-O-Sonic single plane intake thats converted to Multi-point EFI using a 4BBL throttle body.

Thought about intercoolers?

Yes, and I definitely will run one but I am unsure on what brands, styles, sizes, etc would be a good choice.

What about twins because looking at turbofast, they don't want you running anything more than 8psi with a single turbo though I don't think they count stuff like the thumpers in thier calculations. Twins are also much easier to lay out in a custom setup on a V engine.

The only problem with a twin turbo setup I can see is that I don't have a lot of space to work with in the engine bay with the 455 stuffed in there.
The passenger side of the engine compartment has the most room but thats only because the A/C isn't in the car. Once it goes back in then it starts getting cramped.
I was thinking of getting a cheap, used turbo just to use as a crude mockup to see how everything could possibly be laid out. But I haven't found anything yet.

If you really want to go nuts on a single get a Ford Powerstroke turbo, its designed to work with a 7.5L diesel so it should work well with yours.

I'll have to check into that.

Just some food for thought,

Thanks for all of the help!

 

[CTX-SLPR]

Displacement makes a huge difference!!! its not as much about the booste as it is the air flow. A stock headed GN on 23psi can make less power than a GN1 headed motor on 18psi just due the fact the the air is having an easier time getting into the cylinders so your not having to push as hard to get the same or more amount of air in. To really make a turbo work for you, you want to have as few inlet and exhauste restrictions as possible hense big down pipes, and high flow heads and intake make a turbo much happier. With your massive displacement you will be pumping out almost twice the exhauste volume as a stock GN allowing your to power the turbo that flows twice the volume on the inlet. Making insane power on low booste is better than making power on insane booste. For your size application I'd go with the Ford Superduty FMIC though its going to take body surgery to get the plumbing to work. I'm no expert on the sizing of turbos themselfs but as a scientist I can atleast offer up the theory. If your going single, you'll be needing something big to keep from crossing off the compressor map on the high end of your power. If you want to do some price checking on this stuff call one of the major turbo suppliers and find out what they recommend, I'm going to be willing to bet that the Ford Super Duty is going to run out of flow before you run out of revs.

Just more of my rambling,

 

[Drac0nic]

go get a turbo from a Kenworth of about 6L, should be fine for a blow-through setup, A/R's big but then again so's your motor.

An HX-35W off a Cummins turbodiesel can be had cheap (call diesel performance places) it's gated and should give you 500 horse pretty damn easy I'd imagine. The Aforementioned powerstroke turbo would also be an excellent choice. The A/R's probably 1.1 on the exhaust, but you've got the cubes for it. Powerstroke I/C is a good choice, they've been mounted in G-bodies before and they're cheap. Just a *really* rough way to calc what this turbo will do is like so:
Lets just say you've got a diesel turbo that gives peak HP at 3200 RPM (not an unusual redline for a diesel, it'll make power right up to redline usually) Our displacement is 360 cubes roughly so we have 360*3200=1152000. We take this number, divide by your 455 cubes and this is where the turbo will peak roughly. in this case 1152000/455 will give us roughly 2531 rpms. If you're looking for something milder a 6.5L turbo would be good, 6.5s actaully didn't run a heck of a lot of boost (I think it was something like 7.5-8PSI) hence the reason they're anemic compared to the D-max and other diesels.. The thing should provide sweet spool even with a blow through setup and be lots of fun.

Some extra reading for you
http://www.highperformancepontiac.com/tech/0309pon_turbo/

What's your compression, if you've got a high compression engine it will limit your max boost a lot btw. The person I'd talk to about this more in depth would be Disney-Lincoln, he may be worth throwing a PM towards about it. He's got a TT Lincoln, I was talking to a friend who said it's a pretty much stock 5.0 with a blow through setup.

 

[BigBlockOlds]

Originally posted by Drac0nic

What's your compression, if you've got a high compression engine it will limit your max boost a lot btw.

Yeah. Right now its right at 9.6:1. But when switch over to a turbo setup I'll be pulling the 455 out and rebuilding it also.

I plan to do the following:

Custom steel billet crank
Full length main girdle
aftermarket forged rods
lightweight forged pistons
Rocket Racing Aluminum heads and custom intake : Heads and Intake (Forget with the 4.5" cowl hood I'll have room for this setup)
The intake would be fitted for a Multi-port EFI setup. I'll probably go with an Accel DFI GenVII controller if I can't afford a Motec or something similar.

Custom ground hyrdraulic roller camshaft and full roller rockers

I'm also leaning towards the custom headers right now over the modified exhaust manifolds but we'll have to see.
I'll be dropping the compression ratio down to 8.0:1 or thereabouts.

Other than that its figuring out how/where to mount the turbo and which one will work best.

The person I'd talk to about this more in depth would be Disney-Lincoln, he may be worth throwing a PM towards about it. He's got a TT Lincoln, I was talking to a friend who said it's a pretty much stock 5.0 with a blow through setup.

Thanks for the help!

 

[UNGN]

Originally posted by BigBlockOlds
Yeah. Right now its right at 9.6:1. But when switch over to a turbo setup I'll be pulling the 455 out and rebuilding it also.

I plan to do the following:

Custom steel billet crank
Full length main girdle
aftermarket forged rods
lightweight forged pistons
Rocket Racing Aluminum heads and custom intake : Heads and Intake (Forget with the 4.5" cowl hood I'll have room for this setup)
The intake would be fitted for a Multi-port EFI setup. I'll probably go with an Accel DFI GenVII controller if I can't afford a Motec or something similar.

Custom ground hyrdraulic roller camshaft and full roller rockers

I'm also leaning towards the custom headers right now over the modified exhaust manifolds but we'll have to see.
I'll be dropping the compression ratio down to 8.0:1 or thereabouts.

Other than that its figuring out how/where to mount the turbo and which one will work best.



Thanks for the help!

That motor with 9.5:1 pistons will easily make 500-520 HP without a turbo.

If you are going to turbocharge your current Olds and only want 500 HP, Don't bother doing anything to the motor pick a turbo for 5000 max RPM's and blow thru carb.

Your Recipe is for a $15K+, 1000 HP motor, when you can get 500-550 HP for 1/3 that.

 

[ONE_QUIK_6]

My purpose is a multitude of things. The car in general uses to be my daily driver through high school and college. I swapped the 455 in about midway through college and continued driving it everyday. It was my first engine buildup and to be honest, hasn't performed as well as I would have hoped. I also in my haste ripped out a lot of the creature comforts that it once had. A/C, cruise control, etc. I've lost a lot of the driveablity for not much gain in performance.
Now that I am out of college I've turned my attention to fixing the body rust and getting the car to semi-show quality, redoing the engine setup, and this time around, adding all of the creature comforts that I deleted years ago. It will have A/C, cruise, a nice audio system, better manners in driveablity, but at the same time, producing tremendous power.
I'd like something that would at least be in the 12's if not knocking on the 11's without going to a drag suspension setup.
It'll be setup to cruise, road race, etc. You could say its going to be a jack of all trades and a master of none. LOL
[/B]

I don't know if you are really attached to the olds engine, but the numbers you are looking at, spendin and making and your goals, one could put together a very health turbo six. It would meet all your goals and you could probably get better gas mileage.

 

[BigBlockOlds]

Originally posted by ONE_QUIK_6
I don't know if you are really attached to the olds engine, but the numbers you are looking at, spendin and making and your goals, one could put together a very health turbo six. It would meet all your goals and you could probably get better gas mileage.

Has to be an Olds engine.

I'm not one that likes much of the cross-breeding between makes.

If I ever get a turbo V6, I want the rest of the Buick that goes with it.
Thanks,

 

[mygrain]

Instead of using a 5.9 cummins engines turbo, I would use an 8.3 turbo. I firmly believe that with the Rpm of a gas motor you would be exceeding the 5.9s performance range. Not to mention your engine already has almost 100 more cubes than the 5.9 cummins. I would also use a ford power stroke intercooler. I could hook you up with a used turbo off an 8.3 pretty cheap if youd like.

 

[Drac0nic]

Time to jack the thread

Mygrain:got a bead on any 5.9 turbos, I'm looking for one off an Auto (small exh housing) Dodge Ram, the HY-35W. Figure I'd ask since it sounds like you've got a hookup in the realm of diesels.

 

[mygrain]

I'll see what I csn come up with. My name is Jake BTW.

 

[psikuout]

Lets talk Torque instead of HP, the thing that makes a Turbo Buick such a great drag race car is the great torque which is similar to what a good big block should allready have. I'm thinking if you can add even modest boost you will have to have some some serious traction issues! Not to say don't but somthing to consider!