determineing the right turbo size

[Hardymon]

Hi all, I'm new to the FI world, but I'm looking into a single turbo setup. I'm still in the research and shopping phase and was hoping to tap into the knowledge base here.

I'm leaning towards the Huron T4 turbo kit, and now I'm trying to determine what turbo to run with it. I'm leaning towards the Borg Warner S300 series of turbos because I understand that to be a solid brand at a reasonable price with the ability to upgrade in the future as needs change. I am open to other brands if people know of anything that is less expensive, but still better quality than ebay brand. (I'd like to keep the unit under $700 for the time being).

Currently I'm only running some bolt-ons, CAI, ported TB, headers, High flow cats and solo exhaust . My plan is to run on the stock internals for now and run in the neighborhood of 7PSI boost with a goal of 550+ hp at the tires. I'm also planning to add injectors and probably a BAP.

The car is a daily driver and sees a few passes at the local strip once a month or so. What I'm hoping to learn here is what size turbo I should be looking at, specifically with regard to A/R and turbine/compressor wheel sizes. I would like to be at or near full boost by around 3500-4000 rpm with little to no restriction at my current redline of 6500 rpm. I would probably be willing to sacrifice some spooling rate for top numbers so that I can have the power up top without being too much in the boost in the day to day, (assuming that's even a trade I would need to make at this level).

My understanding is that a higher A/R will yield greater peak numbers but slower spooling while lower AR provides faster spooling but can cause restriction at high rpms.

I've tried to google this info, but a lot of what comes up seems to be for rice cars or race cars, and when someone says daily driver things are all over the map. I'd like to see what your personal experiences are with the various sized turbos, what power they make, when the power comes on etc... Also, if anyone has a formula or guideline to follow to determine what these values are, I'd like to see that too. I tried the garret turbo selector app, but it popped up 10 or twelve different turbos that were all slightly different and I'm not at a point where I could "know" what they would do for the car.

As a final note, since "that guy" will inevitably show up, no, I don't want to use a supercharger at this point, and no, I don't want to use twins.

Thanks in advance

[sprayedv]

Twins over single all day everyday.

6266s

[dreksnot]

I can't speak to the sizes, but I can speak to the Borgs. I've been running S200's for over 16,000 miles of 'everything driving' (strip, course, daily) and have had ZERO issues with them.

[AGP Turbo]

S369 SX-E is the best of them.
I don't recommend it but you don't seem interested in explanations outside of what you've decided.

[Hardymon]

I haven't actually decided anything yet beyond using a single turbo setup. I just want something that will fulfill the criteria I've outlined.

I'd be interested to hear if you're aware of something else that you think would fill the needs better than the BW while still maintaining the $5-700 price tag. Do you know what A/R would be best for that turbo? I've seen a number of them in the .88 and .91, but I've not seen as many in the 1.0 housing in the price range I'm looking for.

A friend had a T76 with a .96 and he was full boost by the mid 3s and his wasn't choking at the top, so he suggested that it might be possible to go smaller but to try an see what other people are doing.

Is there any logic to going with a smaller turbine with a larger A/R or maybe a larger turbine with a smaller A/R? How does this tend to affect things? I'm thinking of what will get me into boost on the sooner side without choking at the top.

[kevin87turbot]

Given your criteria, the BW 369 SX-E is a good choice. If you're only looking for 550whp, it will do that with ease. If you're thinking about upgrading from there, both Precision and Turbonetics have some options. What are your long term goals?

[Hardymon]

I think for now I'm looking for 550-600 rwhp. Ultimately just a more fun street car that will be fun for test and tune night at the local track. I've purchased the Huron kit, now I just need to nail down a turbo. Since I'm planning to run less than 10# of boost and want quick spooling for the street over max power for the track, would I benefit from a smaller turbo like the bw 369,or would it be better to go with a larger 76mm style? Also, what AR would be good to run with the different sizes given my goals?

[Hardymon]

I've been looking at the 369sxe units and I can't find any complete units for less than than a grand, which falls outside of what I'd really like to pay. I'm more interested in a "my first turbo" that will be upgraded in the future. Ultimately I want a turbo that will get me into the mid to high 500s rwhp on mostly stock parts and will spool quick for street use. I'd like to avoid the "cheap" turbos, but I'm kind of looking to get the minimum that will accomplish what I want.

[Olddudesrule]

Originally Posted by AGP Turbo

S369 SX-E is the best of them.
I don't recommend it but you don't seem interested in explanations outside of what you've decided.

Anyone else take the last part of that answer as bitchy? I thought the OP's original question was fairly clear and fairly open-ended. I didn't think he was close minded about much, except for the face that he didn't want supercharger or twin turbo info.......Hey, maybe you didn't intend it that way...