Well i'd like to turbocharge my 3.3L straight 6 motor and was just wondering what turbo I should use. It must be cheap and easily available. I am aiming for around 250RWHP (more if possible) if that helps. The cheaper the better I am located in Australia and the reason I am posting here is because there is not much available where I am.

 

A used Buick Grand National turbo should be a good start.

Possibly the larger 2.3L Ford turbo from a five speed...

BW

 

any model numbers to look out for. Will be checking out ebay.

thanks

 

your engine is too small for twin turbo's.

Basically, the whole point of having twin turbo's is to decrease spool up time, but by doing this, you are limiting your maximum PSI.

So, if you wanted the quickest spool up speed possible, you should get two T25 turbos with a .63 exaust A/R rating. These babies will spool up at around 2500rpm with the right cam, but would limit your Maximum boost to around 16psi, which is probably OK if you are leaving your engine stock, since a stock engine ussually cannot handle much over 10psi of boost.

Personally, i would go with a T04B with a .8 A/R Exuast housing, this will spool up at around 3000rpm, but also be able to provide much more than 20psi of boost, so in the long run this would be better.

Plus, going with a single turbo setup will decrease cost and is alot less troublesome.

Also, Twin Turbos are ussually only run a V type or Horozontily Oposed engines, you dont see twin turbos on an Inline engine very often because trying to fit both of the turbos on the same side of the engine can be a hard task.

 

What 3.3L I6? What’s the power band now (how much power does it make and what rpm’s does it make power in, the more info you can give the better an answer we can give), and what kind of vehicle is it in?

Straight 6’s are really nice with power adders since you get the extra mains for a stronger bottom end. Packaging turbo(s) on them is fairly decent since usually you almost have half and empty engine bay. There is a slight advantage to running twins that you can keep the exhaust pulses far enough apart that they don’t interfere with the other 2 cylinders that they’re paired with resulting in better efficiency and spooling with less backpressure.

Without any more info, 250hp will require a 50 or 60 trim T3, I’d probably look for something at least as big as a 60 trim (turbo coupe T3’s or the slightly larger GN T3). There are tons of turbos that are slightly larger but roughly in that range, but probably not as common and without any more info I don’t really have a reason to suggest one. If you did want to go with twins, I’d be looking at some of the smaller T3’s, some of the smaller Mitsubishi turbos, T25’s, even many of the IHI’s out there…

Do you really think that you’ll stick to 250 hp or how much more will you try for?

With respect to the amount of boost… that is just a question of the amount of restriction to the air that the turbo is moving. Most turbos are capable of pushing 40psi or so as long as you put them on something restrictive enough…

 

Not really interested in a twin turbo setup because of space issues.

The engine is a 3.3lt I6 that makes 111HP at 4400rpm. The Vehicle it is in is an Australian 1980 VC Commodore that weighs around 1250KG.

I wouldn't be able to run twins because the head is on a non crossflow design so I have both the intake and exhaust on the same side. Single would be the best way.

Well I thought 250hp would be quite reasonable but more is always better. I'll probably be running about 15psi boost.

Price is the main concern, i'm trying to do this for as low as possible within reason.

Thanks for your help so far.

 

Excuse me for asking (I am honestly curious) but WTF is a VC commodore?

 

Wow, light and underpowered…

Well, to start with, you’re asking for a lot if you’re starting with that. You’ll probably need over 22psi intercooled boost to get 250 hp out of an engine that only flows enough for 111NA, without modifying the engine also.

Quote:

I wouldn't be able to run twins because the head is on a non crossflow design so I have both the intake and exhaust on the same side. Single would be the best way.

heh… I think that a non crossflow design makes it easier… but it’s your choice

Quote:

Well I thought 250hp would be quite reasonable but more is always better. I'll probably be running about 15psi boost.

well, 15psi will put you at roughly 170hp or 210hp with an intercooler… Based on that I’d stick with some of the smaller turbos on that single turbo list before, I think that something like a 60trim/.42A/R T3 would be perfect and should spool well on it. I wish that I had a better clue what you had to pick from down there, but around here I’d be looking for turbocoupe/mercur turbos, some of the larger Saab and Chrysler turbos, some of the Mitsubishi turbos… the little IHI’s like were used on some of the later turbocoupes would never make it to your 250hp goal, but would be very responsive and move enough air for 170-190hp.

Quote:

Price is the main concern, i'm trying to do this for as low as possible within reason.

Unless you are great at fabricating and tuning, turbocharging will end up being harder and cost you more then most other ways of getting that power…

 

The following is a pic of an Holden VC Commodore for those who would like to know. It's not mine by the way, just a pic I found on the net.



Anyways I was actually looking for turbos that would be suitable down your way and they have it sent over to Australia. Any recommendations on what I should choose? It must have an internal wastegate too to keep costs down.

I probably be getting some head work done to it also just to help it flow a little better.

I will be doing all the work myself including fabricating a manifold to mount the turbo.

Anyways thats it for now.

Thanks for the advice so far

 

I'd stick to the ones that I've already listed... something like a T3 60 trim/.42A/R off an early automatic 2.3L 4cyl at the top of my list...

 

A stock Grand National turbo meets all of your requirements. They were used on 3.8 liter Buick V6 engines making 250+ horsepower with 15# boost stock. They are cheap (~$150 used) and use an internal wastegate. Find one that includes the stock wastegate elbow and actuator and you are set.

To make life easier, I'd also buy a used stock downpipe to modify for your application.
turbobuick has a classified section that is a good place to look.

Good luck in your project. Your goals don't seem too hard to obtain.

 

A stock GN turbo will be a little on the big side for that engine, spool slower and has a narrower efficiency range then most of the slightly smaller turbos have. On top of that, it usually costs a little more to get one in similar shape (though it seems that it’s easier to get one for cheaper that needs a rebuild). Will it work, yea, but it will not be the best choice. If you get more airflow out of that engine so that it would be inching up on 170-200hp NA without using a bigger cam then the GN turbo would be a good choice to build 250-300hp. Of course, if you really built that setup I’d probably point you at something a little larger and more efficient like an HY35W off of an automatic, late 90’s Cummins Dodge truck.