What would be the perfect turbo buildup?

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Go for it, You live this life only once.

A free one, done by Gale Banks.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

That is a very broad question, and your goals would have to be the guidlines. And then you say perfect build, Do you mean the engine or the turbo system.

A good turbo system is going to start with the header/manifold. This is going to effect the turbo its self & the performance greatly. A properly built header, plus the right A/R exhaust housing on the turbo is going to allow it to make unexpected performance. For most people a GT35 BB turbo is going to be a good choice. This is going to make up to 650hp on race gas and around 350 to 400hp on pump gas. It would also be a very responsive setup that would work great for street or the strip. It woudl also allow you to use the stock bottom end of the /6 except for a good set of pistons ( like the Venoila pistons) & a set of ARP rod bolts. You could also run a small cam with stock rockers. Head work would also be good, but bigger valve & a little bowl work would take care of it.

A GT67 BB turbo would be great choice also, but its not going to be as responsive and require things like a 3200 stall convertor. Although it is goingt o make better & more power on pump gas than the GT35, plus making as high as 750hp on race fuel. I would also be wanting things like a set of after market rods & light weight pistons for a Build like this. A fully worked & ported head with a custom cam and valve train would also be a good add on with this build.


Jess

There is some good info if you look up the archives. But, for times sake, the t3 is a good choice for most stock slant sixes as if you read the compressor maps it does an alright job. I would take the time to read about maps if you want to get a little more serious. This last months my firends and I have been starting the idea for a build that would combine a subaru turbo feeding a bigger turbo. This summer I'll start the block prepping.
Two things: keep it simple, and keep the boost low is you aren't going into a full out build. I would talk to Sam Powell also if you want some ideas for a cool turbo daily driver set up, it seems like he has a good plan. Also an intercooler is very much worth the money, a simple air-to-air in the front would be worth the money no matter what boost levels.

The T3 is simply to small, yes it will work, but you will be very restricted on the boost level before you run into detination & pinging because of over working the turbo. IMHO The right T4 setup will give as much power on pump gas & low boost as a T3 will at high boost & race fuel. And last longer to boot.


Jess

Can you explain, how one turbo at low boost can make more power then another turbo at a higher boost level? Are you talking about wot boost at the same rpm (ie: 10 psi at 3,000 ) or potential max boost at max rpm ? Are you talking about adiabatic (sp) effieciency (charge temp)? Don't know if I'm wording the question properly. I know a little about turbo's, but most of my knowledge is over 20 years old, and turbo effieciency, has improved many fold, since then.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

I really do not know too much about the science of this. I tried to understand it, but the issues are very complex. I ended up simply buying a slightly used Buick Grand national turbo,and it seems to work fine. But as Jess says, I am still kind of stuck in detonation under boost. To be fair, I have not tried real hard yet to tune it out. I have been working on drivbility issues, which are in pretty good shape now. Also, I think I am going to work out a few issues with the cooling system before I get to the wot tuning. I am toying with the idea of water/meth injection to get out of detonation.

So far, all I have done is very short wot bursts, and when I see detonation on the gauge, I quickly back off and try to take note of the fuel cell/cells where it starts, and go slightly richer, and back the timing off a little. Things are slowly getting better, but I don;t want to do too much tuning until I am pretty sure i have some of the other hardware issues worked out.

Advice for you is this: PLAN CAREFULLY. It is really easy to put the pieces in early on, as there seems to be alot of room in there under the hood. But the further along you get, the less room you have. And the slant is a very long engine compared to a V-6. The v-6 has more room in front of the engine, where they usualy put inter cooler pipes and such. I ended up putting the battery in the trunk to free up space. It is very crowded under there, which is the main reason I have not put the meth injection in. I need to figure out where it would go, physically. I have no windshield washer bottle anymore, and have no radiator overflow tank, which I need to figure out next.

Part of my solution is going to involve a better electrical box. Right now, I have four small add on fuse banks on the fenders, and if I consolidate this into one good fuse box, I can save some space there. But, rewiring takes time, and takes the car off the road for a bit, and there is always the possibility that when I am done something will not work any more after re-wiring. Old systems that work are sometimes kept out of simple inertia, and a bit of fear of change. . So, do alot of thinking before you jump into this.

Also, spend the money to have stainless steel pipes made from the eshaust manifold to the turbo. I did not do this, but will in the Winter. The problem with mild steel is it rusts from the inside, and the bits of rust inside will pit your turbo impellor.

Don't let my cautions turn you off. It is a fun project. I think the main reason they do not turbo v-8 engines is the lack of space. You can make 1000 HP easy with a turbo small block. But ther simply is not room under the hood. The race cars that have this, have nothing else, and no inner fenders.

Sam

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I never looked under the hood of a 301 V-8 turbo Trans Am. I heard they were pigs........

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'72 Duster 198 stock cam, 3:23's Hookers on jack stands for 8 years in the driveway
'79 Maxivan 360 Offy Qjet Comp RV cam/rusting in the driveway.
93 D350 160HP Cummins Auto Dually Clubcab needs a injector pump
2005 Golden Couch Buick

Ifthe Firebird did not run fast, there obviously was a huge compromise in it's design. A local car friend here has a dual turbo BBC that dynos an honest 2000HP. He has run as fast as 6 seconds but most times he breaks somthing. This is clearly too much power for anything but the hardiest hardware, and eventually you manage to find the weakest part in the chain.. It is all under a plastic Willys body on a rail frame. This car(?) is really scary. It is the closest thing to riding a bomb down the quarter mile I have ever seen.

So 1000 HP from a small block is obviously not a big deal, if you can find room for all the parts under the hood of an already tight engine bay. Within given parameters, the higher the HP , the shorter the lifespan of the engine, size for size. You can build a VW engine with turbos that will yield 800 HP but they are good for one road race, and that is it. That is a far cry from the 200K miles you can get out of a stock 50HP VW motor with the same cubes, which I have done.

Sam

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A too-small turbo can create two problems. One, it'll overheat the incoming air, putting you at risk of detonation and dropping the air density for your boost level. Two, the small turbine represents an exhaust restriction. I suspect the latter was why my 225 didn't like to rev past 3,000 RPM with an itsy-bitsy Mitsubishi TE04 off a K-car.

I'm trying to correct that problem by swapping to a Garret GT40, but that may be overcompensating and make for too much lag. The compressor maps suggested it was ideal, but when the turbo showed up, it was the size of my battery. I'll have to see how well it can spool.

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"Mad Scientist" Matt Cramer
'66 Dart - turbocharged 225
My blog - Mad Scientist Matt's Lair

What about the ct26 turbos from an 88 toyota supra my brother has two of those laying around since he wrecked his supra, he says i can have em if i want em?

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Go for it, You live this life only once.

I don't have a map for one, but I suspect as it ran off an engine with similar breathing capabilities it should be fine for a "factory-feeling" turbo car.

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"Mad Scientist" Matt Cramer
'66 Dart - turbocharged 225
My blog - Mad Scientist Matt's Lair

Can a stock slant handle a decent sized turbo? Also if I wanted to go twin turbo, could I put a smaller turbo on the first 3 cylinders and a larger one on the last 3?

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Go for it, You live this life only once.

My understanding from others who have been there is that the bottom end is fine if you keep the rpms low. Don't go above 5K. You actually can get amazing performance from a turbo slant operating below 4.5K since the torque gets the big boost with the turbo. Stock pistons would be suspect. I used Federal Mogul forged pistons, but you can get cheaper alternatives such as the 2.2 Mopar 4 banger turbo pistons. I don't know any of the details of that, but there are others on this forum who can fill you in.

Sam

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I'm putting a GT40 on my stock slant for the time being, but planning to rebuild it sometime in the not too distant future. I've heard of people running 10 psi of boost on a stock bottom end with no problem. The key is to tune it well enough to keep it out of detonation, as that's the real killer.

I would not want to try working with a turbo setup with unequally sized turbos; these are a real pain to get them working right. Sequential or multistage turbo setups are a lot of time, expense, and complexity. Either go with a single or two equally sized parallel turbos.

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"Mad Scientist" Matt Cramer
'66 Dart - turbocharged 225
My blog - Mad Scientist Matt's Lair