turbo choice

[Mathias]

Im in the process of converting my 2332cc to turbo and im not sure what turbo is good for me...the engine is a 2332cc, Cb's Ovalport heads, current cam is a FK46 but will likley change.

Im aming for 15psi of boost and around 300 hp. I would like a ball bearing turbo but can't find any oilcooled ballbearing.

[behappy]

Garratt gt (x) turbo
TD05 turbo.
T3/T4 garrett turbo

[Clonebug]

It would depend on what you are running it in.
If it's a car like a Bug you will have limited choices if using the CBP turbo header down low below the apron.
If you have a Buggy then you have a larger choice.
I prefer Subaru turbos since I have run three of them now and haven't found one I don't like.
A Subaru STI turbo would work well for a 2332 I feel, since they are designed for a 2.5L and are good for 350 hp.

Subaru has their own inlet flange so you would have to custom fit them to a homemade header or modify a CB header.

Otherwise BeHappy has pretty well covered it.

[gbaker770]

Call Mike Merrill at Turbos Direct, he is a VW guy. He can build you whatever you want and a lot of times he has customers upgrade and they will take the old turbos and rebuild them. I got a really nice deal a on a Garrettbillet wheel ball bearing turbo from him.
He's a great guy to work with.

[Piledriver]

The water jacket does not have to be used, its an OEM thing only for when the soccer mom shuts it off after a hard run to Whole Foods to prevent coking. As long as you let the turbo run down and cool off at idle after a hard run its no issue.
Turbo timers exist for that reason.

[Chip Birks]

One thing to note with the small Subaru turbos is that they are designed around an intercooled intake system on a water cooled engine. As clonebug has seen, they are sized to give quick response and can make decent power, but they also tend to make a lot of heat in the intake air. High intake temps can be very detrimental when running lots of boost on cheap pump gas. Make sure you plan on ways to keep temps down. Clone has had very good results from a homemade water meth system.

I am a very content t3/t4 user. These hybrid turbos provide good spool and efficient compressor wheels allowing us to make boost quickly and keep temps down. My current turbo is probably a little on the large side compared to what most of you want, full boost by 4000ish rpm on a dyno in 3rd gear. But I did that with top end power in mind. My 2276 makes enough low end power off boost to make cruising around entertaining enough. With an air to water intercooler in place, I see intake Temps increase by 10 or 15°F during a hard boosted 2-3 gear pull. I can't say how it would work without the intercooler as I've never run this setup without it.

[Clonebug]

Most heat is a product of compressing the air and not specific turbo related.

One of the calculators I use on the RB Racing website correctly calculated the heat increase of my first turbo almost to the degree so I feel that the turbos I use don't heat air any more or less than any other turbo.

http://www.rbracing-rsr.com/intercoolers.htm

I used 13 lbs boost and 80 degree inlet temp with 0% intercooler efficiency which comes out to 186 degree temp at the turbo outlet.
When I was running that boost with the RHB5 turbo and no WI that was the exact temp on my logs.

186 degrees.....

[Piledriver]

I think what Chip was referring to is where you are running on the compressors efficiency map.
For a given pressure, the OAT will be much lower in the center of the compressor efficiency map at ~78% vs. wound out at its limit at 55%

That's where you end up with too small a turbo.

[Clonebug]

I think what Chip was referring to is where you are running on the compressors efficiency map.
For a given pressure, the OAT will be much lower in the center of the compressor efficiency map at ~78% vs. wound out at its limit at 55%

That's where you end up with too small a turbo.

That would be true.
On my old turbos I was probably out of the efficiency range but with this new WRX turbo I'm probably right in the best range due to it being able to support over 270 hp and I'm not there........yet.

[Chip Birks]

Im aming for 15psi of boost and around 300 hp.

This is why I said what I did. Requires a pretty efficient turbo on our aircooled engines.

[MarioVelotta]

Another huge factor to consider it that Chip is running 2k more RPM than Clonebug. 5500 vs 7500. That plays a big role in turbo choice. If you were to run at 5500 Chip, you certainly wouldn't be happy with your T3/T4?

[Chip Birks]

I think my other one with the .48ar turbine housing would have been better for the lower rpm windows, this .63ar setup definitely enjoys rpm, but so do I. I don't know how you guys shift before 6000rpm! At least in first gear. Mine is there too fast to do much else if I'm being aggressive at all.

I will also point out that my boost and rpm lines on data logs track each other almost exactly. Both peaking at the same time. This is the case on the street at least. Not what most of you would like for a daily driver street car, but mine is a daily driven race car(just got home from an ice cream run in fact), so its okay with me. On the track, boost holds nice and flat once it peaks.

[MarioVelotta]

I had a .48 on my 2.2l. It just wouldn't have been as good with a larger AR.