Turbo sizing for a 700 rwhp combo

[RED09GT]

Most other threads I have found are either getting old or are guys looking for a grand or more at the wheels-that is too much for me and the reliability is enough of a liability at the power levels that I am looking for.
Basically, I need right around 700rwhp to hit the trap speed (135mph) and low 10's that I desire. I say it now (and I reserve the right to change my mind) but I really don't want to go faster than that with this car. I have a 6 point rollbar but don't want more than that. I'll build a dedicated drag car if I feel the need to go faster.

Here is what I want:
135mph in the ¼ mile (3800lbs car with me in it so around 700 rwhp)
Pump gas friendly, 94 Octane-No ethanol. Water/Meth system for track tune up
~575-600 rwhp on the street, pump gas
Good boost response
Something with a T4 flange, 3 to 3 5/8” V-band discharge less than 1.00 a/r housing
“S” compressor cover 4” in/ 2 ½” out (compatible with current charge pipe setup)

What I have:
Stock block 0.020" over
Diamond 15cc pistons
Eagle H-beams, ARP 2000's
Kellogg Cobra Crank
Zero decked, heads milled to 48 cc chambers, Depending on the calculator it comes out to somewhere around 9.3:1
Ported heads, stock valves
Cams are 227/227 265/267 .550" lift 115.5 LSA, locked out at 108.5 ICL
TFS 154100 springs (pretty much the same as comp 26125's)
TFS Adjustable crank sprockets
McLeod RST Clutch
TR6060
3.55 gears
Greddy Profec B spec 2 boost controller
60 Lb injectors (will step up to something in the 1000cc range when swapping turbos)
GT500 dual fuel pump setup (can add a booster if needed)
-8AN fuel line from the hat to the fuel rail
Powerhouse Turbo Kit
Precision 6776 entry level turbo (rated to 755 hp) 3” inlet/2” outlet 65.5mm compressor inducer, 64.5mm turbine exducer, .81 A/R housing

Here are some of the turbos that I have read up on and I would like to get opinions of how some of these newer styles, somewhat small turbos will do with a middle ground build like this. Most of these turbos are from the import crowd, which makes me wonder if am I overlooking something important?:

Precision 6870 Gen 2 CEA, rated to 1100 hp
https://www.precisionturbo.net/Stre...-and-Race-Turbocharger---GEN2-PT6870-CEA®/578

Comp Turbo part # 436871 Ceramic Ball Bearing, rated to 1100hp
https://ostarmotorsports.com/Store/Product/CT4-Billet-3BB-68-71

Garrett GT4294R (Turbine housing options are a bit big)
https://www.maperformance.com/products/garrett-gt4294-gt4202r-turbocharger-500-1000-hp-gt42r-gt42rs

Turbonetics GTK-850, or GTK-1000, rated to 850 hp and 1000hp
https://turboneticsinc.com/store/index.php?route=product/product&product_id=91

Borg Warner S369SX-E 69/73 (Only Journal bearing turbo of the bunch, but half the price of the others), rated to 1000 hp
https://agpturbo.com/borg-warner-s369sx-e-69-73-13009097051/


Any other suggestions?
Should I just get something more conventional like a Precision PT7275, or a 7675? Will it be happy at lower boost levels-or will it be doggy?

I also looked at the ball-bearing Borg Warner EFR units but the turbine housings seem way huge and the layout of their websites makes research a bit difficult.

What would you suggest?

 

[weather man]

My Garrett GT4094R made 701 at 12 psi and 707 at 13 psi. Had stage 1 heads and turbo cams.

 

[RED09GT]

My Garrett GT4094R made 701 at 12 psi and 707 at 13 psi. Had stage 1 heads and turbo cams.

That is an excellent option. I had found the GT4088 and GT4294;and wondered if there was something in the middle.

 

[JeremyH]

Most other threads I have found are either getting old or are guys looking for a grand or more at the wheels-that is too much for me and the reliability is enough of a liability at the power levels that I am looking for.
Basically, I need right around 700rwhp to hit the trap speed (135mph) and low 10's that I desire. I say it now (and I reserve the right to change my mind) but I really don't want to go faster than that with this car. I have a 6 point rollbar but don't want more than that. I'll build a dedicated drag car if I feel the need to go faster.

Here is what I want:
135mph in the ¼ mile (3800lbs car with me in it so around 700 rwhp)
Pump gas friendly, 94 Octane-No ethanol. Water/Meth system for track tune up
~575-600 rwhp on the street, pump gas
Good boost response
Something with a T4 flange, 3 to 3 5/8” V-band discharge less than 1.00 a/r housing
“S” compressor cover 4” in/ 2 ½” out (compatible with current charge pipe setup)

What I have:
Stock block 0.020" over
Diamond 15cc pistons
Eagle H-beams, ARP 2000's
Kellogg Cobra Crank
Zero decked, heads milled to 48 cc chambers, Depending on the calculator it comes out to somewhere around 9.3:1
Ported heads, stock valves
Cams are 227/227 265/267 .550" lift 115.5 LSA, locked out at 108.5 ICL
TFS 154100 springs (pretty much the same as comp 26125's)
TFS Adjustable crank sprockets
McLeod RST Clutch
TR6060
3.55 gears
Greddy Profec B spec 2 boost controller
60 Lb injectors (will step up to something in the 1000cc range when swapping turbos)
GT500 dual fuel pump setup (can add a booster if needed)
-8AN fuel line from the hat to the fuel rail
Powerhouse Turbo Kit
Precision 6776 entry level turbo (rated to 755 hp) 3” inlet/2” outlet 65.5mm compressor inducer, 64.5mm turbine exducer, .81 A/R housing

Here are some of the turbos that I have read up on and I would like to get opinions of how some of these newer styles, somewhat small turbos will do with a middle ground build like this. Most of these turbos are from the import crowd, which makes me wonder if am I overlooking something important?:

Precision 6870 Gen 2 CEA, rated to 1100 hp
https://www.precisionturbo.net/Street-and-Race/ss/1-000-1-200HP/details/Street-and-Race-Turbocharger---GEN2-PT6870-CEA%C2%AE/578

Comp Turbo part # 436871 Ceramic Ball Bearing, rated to 1100hp
https://ostarmotorsports.com/Store/Product/CT4-Billet-3BB-68-71

Garrett GT4294R (Turbine housing options are a bit big)
https://www.maperformance.com/products/garrett-gt4294-gt4202r-turbocharger-500-1000-hp-gt42r-gt42rs

Turbonetics GTK-850, or GTK-1000, rated to 850 hp and 1000hp
https://turboneticsinc.com/store/index.php?route=product/product&product_id=91

Borg Warner S369SX-E 69/73 (Only Journal bearing turbo of the bunch, but half the price of the others), rated to 1000 hp
https://agpturbo.com/borg-warner-s369sx-e-69-73-13009097051/


Any other suggestions?
Should I just get something more conventional like a Precision PT7275, or a 7675? Will it be happy at lower boost levels-or will it be doggy?

I also looked at the ball-bearing Borg Warner EFR units but the turbine housings seem way huge and the layout of their websites makes research a bit difficult.

What would you suggest?

After all my experience with turbo setups, I have to say, I am on the same page, I am a big fan of using just enough turbo to get to your target power goal and rpm and no more. This maximizes your power band, transient response, spool time and brings torque in sooner and makes the car so much more fun to drive.

I battle with this all time I am over the hp number thing. I find it I enjoy the car the most running around 600-700hp range. I currently have a turbo (7275 with a 1.15ar) that will do 900hp+ to 7500rpm. But I don't rev that high nor plan to make that much power anymore. The most fun I had was a gen1 billet comp 7068 fucker with a .68ar that made 640rwhp and 700rwtq+ and ran out of steam around 6200rpms. Was a monster, and a complete blast to drive.

When/if/when I step back down like you are talking about I will be getting the comp 6871 with the gen2 savage wheel ceramic ball bearing oil-less with .81ar. I know it will easily make 700rwhp to 7krpms and be a blast to drive.

I have a very similar engine setup to yours, minus the ported heads, mine are stock. 15cc diamonds around 9:1 compression, 6060 and 3.55s as well.

My first turbo setup had an old precision 67, was lazy, went to a billet 67 and lost of mind at how much better the performance was spooled 1000rpm faster and picked 100hp+ 100tq+ at 3500rpm made 650rwhp with it. Then I ran that comp billet 70 with a new hotside like I mentioned earlier which was by far the best turbo I had. Then I went twins and made around 770rwhp at 16psi, realized they weren't for me as it alot of top end power mixed with a stick car and now I am back to single lol. Ever since that gen2 savage wheel from comp came out back in January I have been seriously thinking I dropping down size again. That 68mm savage wheel moves air like a 76mm cast wheel and spools like a 60mm. I need it in my life lol.

 

[RED09GT]

Ever since that gen2 savage wheel from comp came out back in January I have been seriously thinking I dropping down size again. That 68mm savage wheel moves air like a 76mm cast wheel and spools like a 60mm. I need it in my life lol.

Is that the X-HF 2.0? If not, do you have a link so that I can read up on it?

I am leaning towards the 6871 comp at the moment.

 

[JeremyH]

They do have some info on their site, also If you do facebook they post a lot of stuff on their page on there. I have been using comp since 2011 so have a lot of experience with them as well.

http://compturbo.com/spotlights/billet-wheels

I can tell you they are quite capable units. RJ was able to put down 722rwhp @18psi on a 6765 with a .81ar journal bearing. That's fully maxing out that unit though.

Welp here are the numbers on 15 psi and 18 psi. I am beyond thrilled!

Video is uploading.

Thanks guys! Jeremy I will do that now!


Heres the Video of the pull!

Even the 6767 which is the next size smaller than the 6871 would do what your wanting. RJ's 67 was a standard wheel as well, not even a billet gen 1 or gen 2.