Yet another turbo selection thread, but this time with info!

[Maetrix66]

I am going to be running a 96 3100 with hyperteuctic 3.1 VIN T pistons with teflon skirts.

I have a Garrett T3 turbo with a .42 wheel, and am also running a saab 900 intercooler. I have about 4.5 feet of 2.5" mandrel bent pipe total from the compressor to the throttle body, and a TurboXS BOV, the big one with the horn cast onto the side.

Half of this infomarmation isn't useful for the questions I am about to ask, but I thought that since most people give too little information when they ask, so i am trying to compensate by giving too much, LOL

Here we go.

1. Is this turbo large enough to feed my engine at all RPM's??
2. What boost levels should I be able to get from this setup??
3. Kinda redundant, but will this turbo flow sufficient air to run 12 psi on my engine??

[Guest]

1. No
2. You can run big boost levels with that turbo but that doesn't mean squat if its blowing hot air. Boost is a measure of intake inefficiency.
3. No

Trash that turbo. Let me guess you pulled off of a junkyard t-bird or maybe even a chrysler 2.2 engine because it was cheap?

[BrianC72bgt]

How to choose the correct turbo? You need to figure out a couple of things.

What is your target horsepower?
How much air do you need to flow to acheive this goal?
A bigger turbo spools at higher engine rpm- what rpm is acceptable for onset of boost?

You've got to figure out what amount of flow you "need" (or are willing to accept) with the understanding that the most power at 7,000 rpm might result from a turbo that doesn't spool until 4,500 wheras a smaller turbo that produces less torque will come on line at 2,500 rpm and be a lot more useable in daily driving.

Drag Strip monster or Daily driver with a sleeper factor?

I did a search on turbocharger sizing and came up with the following site. There are lots of them.

http://www.turbocalculator.com/garrett.html

I sound like a broken record, but with good reason: Buy Corky Bell's book Maximum Boost and read it cover to cover twice. Then you will know exactly how to estimate the size and flow charateristics you need to pick the right turbo for your goals. You will also have a good idea how to design and build a complete turbo system taht will run well and not blow up.

Regards,

Brian C.

[Maetrix66]

Turbo

Nah, the turbo was rebuilt by garrett, and is in perfect condition.
I got it reasonably cheap, but figured that since this was to be a daily driver with occaisional runs down the 1/8th mile, I wanted to have a turbo that spools quickly. I plan on running about 10-12 psi of boost, and will be running a Saab 900 intercooler and water injection.

I understand the flow of a turbo and the dynamics behind that, but as far as the turbo blowing hot air, I'm a little confused. Doesn't a turbo heat all air that passes through it? I'm not sure how the turbo losing efficiency would make the intake charge temp rise. I'm pretty new to turbocharging, but I have dealt with supercharging for awhile. They are completely different in thier operation, agreed, so I guess I'm only starting slightly ahead of your average turbo newbie.

I am looking for quick spool, with as little lag as possible. I don't see this engine in it's current form running over 5500rpm, since the gearing of the transmission is pretty steep. If the turbo could maintain decent efficiency and make decent power from 2000 to 4500-5000 I would be happy, since this is where I will be spending most of my time in the powerband.

[93LuminaZ34va]

I'm with the rest of them.... that .42 wheel is 4 banger fare. It will feel kinda corked up on that 3100....

[Maetrix66]

So, the concensus is that I should sell the turbo, and buy a hybrid?? (T3/T4)?? With something around a .63 wheel in it??

Anyone want to buy a T3 turbo??
Or trade for something bigger??

[Maetrix66]

Turbo

So, would this turbo work for now if I keep the boost low, to stock TGP levels?? I want a turbo that will spool quick. I may hold off temporarily on going all out due to other issues (fuel pump, injectors)

So, will this turbo work for light duty?? I will buy a hybrid turbo when I get my other engine built before I go to 14.5 psi, I just built the system (engine management) around being able to handle it.

I have plans on making a main girdle for the 3100 (along with the accompanying oil pan), along with a new exhaust manifold (not header) design for boosted apps. It will flow better, but will employ some interesting tricks to keep the low end happy. I realize this is down the road a little, and I need to learn how to crawl with this setup before I start trying to run, but the design is almost complete.

[TurboGTU]

You mentioned a .43 A/r t3...Is that the compressor or turbine? Well either way...Early ford Turbos 2.3s had a small turbo...prob might be the one you have...but in 85 and on they had the bigger (I).60/(E).63 T3 turbo. THese are the most bundiful and popular turbos to work with. Later 87-88s had a smaller IHI.

If its a .45 A/R T3...it will feed you with 170hp and give you lagless and torquie power all the way to 4K rpm. I would say you could get away with 10psi from 2k-3500 rpm..but from there after you'll need to turn it down to 5psi or so. Of course this is just a guesstimate. You should really think about porting you exhaust ports. They only flow 114cfm. You don't need to worry about the intake. You should look more on CFM and Density ratio, target power and powerband.

[Maetrix66]

Boost?

I am able to get my hands on a t3 60 trim turbo at a reasonable price. My goals for this engine are about 8-10 psi max. I already have a intercooler installed, a saab blackstone with a water misting system, and am also mulling installing a water injection system, but I think that this may be overkill at the present stage.