Birdie2000

iTrader: (15)

I'm sure this has been discussed before but searching wasn't bringing anything up for my specific application (stock cam, daily driver, no racing). Looking for turbo size recommendations.

Car is an 02 Z28 w/ T56. Engine will be a stock 42k mile LS1 with the normal valvetrain upgrades. I will be keeping the stock cam for drivability/sound reasons. Turbo kit will be the Huron Speed V2 A/C kit and rear gear likely 3.42 or similar.

The car will be daily driven for 6 months out of the year. It will likely never see the track. I basically want stock drivability, quiet, and reliable.

So far everyone seems to talk about the PT7675 as being the end-all-be-all turbo for a 346ci setup. The difference is, I am not worried about racing or times at all, it will be a true daily driver. I want something with the broadest torque curve and best responsiveness possible for daily driving situations, while still being reliable. Something similar to what an OEM would do if they were making a turbo engine. Looking for around 500-550rwhp on 93 octane. Would I be better off looking into a 67mm turbo? Or will the PT7675 give me the responsiveness and torque I'm looking for?

Forcefed86

iTrader: (4)

BW S366 would be another to look at. Could easily hit those power levels.

JetMech99

iTrader: (3)

Your setup sounds EXACTLY like mine and I'm running the Turbonetics TC76 with great results. It even made exactly your HP goal of 550 RWHP at 7psi. It's a great cheap turbo that will do everything you're looking to do with your setup.

Just noticed you're only an hour down the road if you ever want to check the car out in person, or go for a ride after I break my clutch in.... just let me know!

Birdie2000

iTrader: (15)

That sounds awesome. How's the spool time and responsiveness during around town driving? Are you using meth or straight 93?

LS1-IROC

iTrader: (4)

I have similar goals/set-up and bought a TC78 based on recommendations and research. Still putting it together so no numbers yet, but I know it will produce more than what my goals are.

Superman09

iTrader: (65)

TC76 or TC78 will be a great choice for your set-up Jim. If you want something that can be pushed harder down the road, then look into the 7675, however for a street car, stock bottom end, t56 set-up the tc76 or tc78 will perform excellent and spool quickly. JetMech is good people, if you don't take him up for a ride I just might for a fun day!

Forcefed86

iTrader: (4)

If the guy truly wants 550hp then running a 76mm with a small exhaust wheel (TC series) is going to perform poorly compared to an S366 response wise. Last I checked the S366 was cheaper as well. You also don’t need a 76mm compressor for 550hp. A compressor that big isn’t as efficient at low boost as a 66mm compressor would be. At the OP’s desired power level, the S366 would blow the TC76/TC78 out of the water hands down IMO.

Superman09

iTrader: (65)

A BW S300 will not bolt onto the kit without modifications, different frame.
We have used the TC76 and TC78 along with tons of customers on stock displacement set-ups and they perform excellent providing great power and excellent spool time.

JetMech99

iTrader: (3)

It's been since last summer since I laid the coal to her, but if I remember correctly, I'm full boost by 3k-ish. I have a meth kit on the car, but she was tuned without it, so made those numbers on straight 93. The car was tuned by Vector Motorsports in Clinton Township... also not too far from you. Good people to work with!

lol thanks Jon! That white beast of your makes mine look like a Honda Civic, so a ride in mine may be a bit boring to ya!

Forcefed86

iTrader: (4)

Not trying to be a smartass, but “excellent spool time” compared to what? I 100% agree that either of the 76/78 series mentioned can make 550 hp on the OP’s setup. There are a lot of turbos that would be more responsive and still meet a 500-550hp goal. Why not a TC66 with the F1 turbine or the 72mm Hurricane “Sylvia” if he wanted room to grow? Either of those would have better response and still make the power.

Personally if I were building a manual trans DD turbo car, I’d want the quickest response possible that still met my goal. Selecting a turbo with an oversized compressor and a 10mm split between the exh and comp wheel seems like a poor choice.

Superman09

iTrader: (65)

On these types of set-ups the split in wheels really performs just fine, has been proven time after time. The larger compressor wheel in this type of scenario will give him more room to grow down the road while still being very responsive. I agree you could go smaller on the compressor and achieve quicker spool time, but when a customer tells me they only want 500-550hp, 9 times out of 10 they are going to want to up the boost the day after they get off the dyno

Orr89rocz

iTrader: (13)

I was gonna say the spool time on the tc76 would be fairly fast in an ls1. I run the 72mm hurricane (tc72 basically) on a 3.3l and its alive by 3500 with a loose converter and .81 ar. No doubt you could have good spool on a 5.7 with either .81 or .96 ar but could even go tighter .68 and still make that power.
I agree tho 76-78 wheels are not needed, just sayin the smaller 68 f1 turbine wheel will be very responsive.
I would run the hurricane 66mm stuff on this car since borg 300 wont fit. It should do 500-550 thru a stick.

Birdie2000

iTrader: (15)

Thanks for the input guys.

Jon - What needs to be modified to make the S366 fit? I like the idea of that turbo from my research, and the reliability that BW seems to be known for would be great as I plan to put 8-10k miles a year on this car and take it on road trips. Also, I have no plans to build the engine so as long as my dyno number starts with a 5 I'll be happy. Now I wouldn't complain if it was 599, but I also don't care (too much, lol) if it was 501. I have no issue with buying a new turbo if I ever need more. Also want to make this power without meth so that's a factor too. I'm much more concerned about drivability & reliability than I am power numbers.

JetMech99 - Would love to take a ride sometime! Let me know when.

Forcefed86 - Thanks for your input, that's very helpful and was what I was gathering from my research. I'm getting fairly set on the idea of a ~67mm turbo as long as it doesn't have any large negatives.

The BallSS

iTrader: (9)

I'm actually currently doing a TC78/Huron Speed V1 build blog right now! I have no numbers yet but my goals are identical to yours. Trust Jon because when I reached out to Pat G. for tuning info he told me EXACTLY what Jon said about drivability, spool and horsepower plus Pat said I would have an extra fat midrange torque curve at tip in which as you know is what you want in a street car. The Huron Speed kit fits really nice too cause there ain't much room under there lol!

02LS1ram

iTrader: (17)

I have the Hsp v1 kit with a pt7675, I wouldn't go any other way with a sbe5.7
My car makes full boost at 2900-3000 rpm's 11psi 623whp. It's fun as hell to drive with the 6speed. The only issue your going to run into is traction on an street tire. Personal the tc76/78 will choke way to quick, now your stuck having to upgrade. I have no experience with the TC 7675 so maybe some will chime in.
I say go with the PT7675 and don't look back. Just my 2 cents

JetMech99

iTrader: (3)

Are you running a stock bottom end LS1?

The BallSS

iTrader: (9)

I heard that the PT7675 won't work on the V1 AC kit without modification? Did yours bolt right up because I'm running the TC78 and am also curious about the PT7675 as a potential upgrade.

Superman09

iTrader: (65)

Will drop right on, same flanges. The compressor housing is a little larger so you may need to push the radiator/condenser forward some for some more clearance but other than that and a silicone coupler change you will be good to go!

PewterZCar

iTrader: (2)

I would get a 76 68. I had the cxracing version (talk trash if you want it lasted 20k before I upgraded) and it made full boost by 2500rpms. I loved dd'ing the car with the 6speed. I made 616rwhp at only 7lbs of boost.

The BallSS

iTrader: (9)

That sounds perfect! I have a TC78 w/ the 68mm turbine w/ a 1.15 AR and if I could make anywhere near that with it at 6-7 lbs I'll be happier than a pig in **** lol. Hey jon, is that because the compressor outlet is a different size than the TC76/78?