Which turbo would you all prefer?

[Fialchar]

I can get either a T3/T4 hybrid or a T67 for roughly the same price (About $500) from V & T Performance. Which one would you all choose, or which one do you all think woul be better for my car (Remember, I no longer driver a Vibe )

[MadBill]

Tricky question, Fialchar. Turbo sizing is part science and part black art! A lot depends too on what the engine mods if any are and whether good mid-range torque (and lots of top end action by the wastegate) is desired, or the leisurely spool-up and tremendous top end charge of a bigger unit. One factor not often mentioned is that a typical aftermarket kit creates maybe twice as much back pressure as it does boost, and thus should be matched with custom short duration cams to prevent pushing a lot of exhaust back into the intake during the valve overlap period. A bigger, custom matched turbine, compressor and housing with a very free flowing exhaust can have the backpressure no higher than the boost and thus works well with the stock cams. There are several good books (e.g. the ones by Bell and McInnes) on the subject and a number of outfits have developed specialized software plus a ton of experience on speccing the perfect combo.

[joatmon]

I thought your saab 9-3 turbo already was turbo'd. You might get better Saab 9-3 specific advise on a Saab forum. I mean, feel free to ask here, no problem, but I don't know if there are many Saab experts here

[Fialchar]

Thanks for the input MB and Joatmon My Saab does have a turbo, a TB25, but it'd be nice to have something that adds a bit more boost

[Faultline]

Quote, originally posted by MadBill » There are several good books (e.g. the ones by Bell and McInnes) on the subject and a number of outfits have developed specialized software plus a ton of experience on speccing the perfect combo. wow MadBill, Your vast knowledge never ceases to amaze me! "Turbochargers" by Hugh McInnes is the one that I read. Most people on-line seems to be more familar with the book by Corky Bell "Maximum Boost" for some reason. I learned a great deal from MacInnes's book, It gave me the confidence to go ahead with my project....Fialcher, what size motor are we talking about??

[ShotInTheDark]

I'm very close to buying an STS remote turbo for my silverado SS. 155hp upgrade...

[Fialchar]

It's a 2.0L inline 4, L4 ecotec engine made by Saab with a stock TB25 turbo

[MadBill]

Quote, originally posted by Faultline »wow MadBill, Your vast knowledge never ceases to amaze me!...With five plus decades frittered away on cars and motorcycles, some useful stuff is bound to stick...

[Jahntassa]

Quote, originally posted by MadBill »With five plus decades frittered away on cars and motorcycles, some useful stuff is bound to stick... Sorry, I just had to say that frittered is an awesome word.

[Faultline]

Quote, originally posted by Fialchar »It's a 2.0L inline 4, L4 ecotec engine made by Saab with a stock TB25 turbothe t3/t4 hybrid is plenty big IMO...It will be very efficient making good power...most likely wont be fully spooled until 4k, but note the word "fully". You will get some boost before that though.. There are different size turbine housing, compressor housing, turbines, and impellers in the same term "t3/t4". A lot will depend on those factors even to make what I said true. If you have no clue about the terms I just stated then I will try to explain as simple as I can. A turbo has a shaft with two fan type wheels on each end. On one end is the "turbine" wheel, which the exhaust gasses spin. It sits in the "turbine housing" . On the other end of the same shaft is the wheel called the "Impeller".It sucks in the air and blows it out of the "compressor housing". The turbine can come in different sizes in a "turbine housing" , and the impeller can be different sizes in a "compressor housing". A t3/t4 hybrid is a combination of a a T3 turbine and a t4 comressor. As I stated, (And which is very confusing) the turbine,turbine housing, impeller, and compressor housing can all be different in two turbos both still called t3/t4 The 2 books that MadBill eluded to would be a big help to help make your decision!...Or just take the advise of whoever is going to swap turbos for you....and see what happens!

[Fialchar]

Well, Nate (He's the import mechanic I know, the same one who offered to mould a custom kit when I had the Vibe) lives by the T3/T4. It's the turbo that he ordered to put into his Talon tsi AWD, and he says it's enough boost in just about any application.I have some turbo knowledge, but nothing on you or MadBill. Maybe I'll go ahead and buy one of those books so I can understand them instead of just knowing about them Again, thanks for the input ^^

[mu_ohio]

We really like the GT28RS for the Protege which is a better match than a T3/T4. If you can snag one of those for cheap, then go for it. They are good up to 350 hp I believe and have a faster spool.

[ShotInTheDark]

I've told you guys about the STS kit I'm looking at for my truck which is a remote turbo. I wonder if they could do that as well for the vibe? I'll have to ask when I call to order my truck kit.