how much hp gain can be expected
10-19-2013, 04:17 PM
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how much hp gain can be expected my friend has a 260z with a 6.0, 317 heads, ls6 cam with a whipple blower making 6-7psi.. right now its running 10.20 at 130's and made 470rwhp.. he wants to run mid 9's and 650rwhp..
I suggested getting some 243 heads with a mild porting, an appropriate supercharger cam and possibly turning the blower a bit harder.. you guys think that would reach his goals?
I suggested getting some 243 heads with a mild porting, an appropriate supercharger cam and possibly turning the blower a bit harder.. you guys think that would reach his goals?
Last edited by dezlfrek; 10-19-2013 at 05:56 PM.
10-19-2013, 10:44 PM
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from what he is thinking the blower is already turning at or close to its max rpm, I said I would just spin it higher also. Ill have to get the blower specs and pullies so we know.. but doing some mild head porting and a cam should get him there all together easy right..
10-20-2013, 12:00 PM
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I don't know Adam. Most of the people I've talked to have said that the 112 is a bit too small for the 6.0 and really isn't designed to make much more than what I'm getting. I think selling the engine complete to some street rod guy that doesn't want a .030 over .010/.010 crank 350 like every other street rod guy might be a good option. Build another lq4 block with a 408 kit to get as much off boost torque as I can with better heads and cam, and then set it up for a single turbo with a t6 flange so I can play with turbo's until I find what works. Maybe even use a BW 72/83/1.1 for daily driving, and something larger like a 75/96/1.32 for trips to the track.
RonA
RonA
10-20-2013, 02:19 PM
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or why not just go with a bigger blower Ron? but as these guys suggest I would just pull that blower and do a single turbo kit on the 6oh and be done. I bet you could sell the blower for the same cost as a turbo system would cost..
or you could be really different and but a turbo system on top of your blower... win win in the torque and hp department.
or you could be really different and but a turbo system on top of your blower... win win in the torque and hp department.
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10-21-2013, 11:14 AM
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If the larger version is any longer on the back side, it probably won't fit. Clearance is limited in back, but there is quite a bit of room between the radiator and the front pulleys. I've been looking at turbo dyno graphs to see where the power starts and most seem to not start coming on until 4k rpm. That would suck. 3k would be a lot better even though it's a little harder on parts.
10-21-2013, 06:52 PM
#11
My setup should be full boost by 3k rpm. Ur probably looking at improperly sized turbos to certain setups. If you put an 88mm on a 5.3, u won't make power until 4k... gotta size the turbo properly to engine displacement and pick the right cam. U can make power at 2500 rpm.easy.
10-22-2013, 03:43 PM
#15
The large majority of people don't properly size a turbo for their engine. They pick something huge, run it at 60% of its potential, and then complain about boost not hitting til 4K RPM.
Even a small turbo with a small A/R turbine can make 600whp and make more low-end than a supercharger.
A properly sized turbo will spool up fast enough to out-torque a supercharger on the low-end. Superchargers build boost by RPM, turbos build boost independent of RPM. A small turbo can hit 10 PSI at 3500 RPM while a supercharger capable of making 10 PSI would take 5500+ RPM to do it.
Turbo setups can also be done fairly cheap, even cheaper if you can weld yourself. I bet if you sell the S/C setup you can break even on a turbo build.
Even a small turbo with a small A/R turbine can make 600whp and make more low-end than a supercharger.
A properly sized turbo will spool up fast enough to out-torque a supercharger on the low-end. Superchargers build boost by RPM, turbos build boost independent of RPM. A small turbo can hit 10 PSI at 3500 RPM while a supercharger capable of making 10 PSI would take 5500+ RPM to do it.
Turbo setups can also be done fairly cheap, even cheaper if you can weld yourself. I bet if you sell the S/C setup you can break even on a turbo build.
10-22-2013, 05:16 PM
#16
The large majority of people don't properly size a turbo for their engine. They pick something huge, run it at 60% of its potential, and then complain about boost not hitting til 4K RPM.
Even a small turbo with a small A/R turbine can make 600whp and make more low-end than a supercharger.
A properly sized turbo will spool up fast enough to out-torque a supercharger on the low-end. Superchargers build boost by RPM, turbos build boost independent of RPM. A small turbo can hit 10 PSI at 3500 RPM while a supercharger capable of making 10 PSI would take 5500+ RPM to do it.
Turbo setups can also be done fairly cheap, even cheaper if you can weld yourself. I bet if you sell the S/C setup you can break even on a turbo build.
Even a small turbo with a small A/R turbine can make 600whp and make more low-end than a supercharger.
A properly sized turbo will spool up fast enough to out-torque a supercharger on the low-end. Superchargers build boost by RPM, turbos build boost independent of RPM. A small turbo can hit 10 PSI at 3500 RPM while a supercharger capable of making 10 PSI would take 5500+ RPM to do it.
Turbo setups can also be done fairly cheap, even cheaper if you can weld yourself. I bet if you sell the S/C setup you can break even on a turbo build.
10-22-2013, 08:07 PM
#17
It was just a generalization. Neither the PSI figure nor the RPM figure were supposed to be taken as actual numbers. I was just saying that belt-driven boost is linear, most superchargers don't top out their boost figure early/mid in the RPM range like turbos can.
10-22-2013, 08:14 PM
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I actually have played with turbos a bit, just not on a gas powered vehicle. Only having a tiny bit of boost with big head flow is a strange concept, so it will take a while to pick a good starting point.
10-22-2013, 08:37 PM
#19
Roots and twin screw blowers are able to make tons of torque down low with great throttle response. Boost with these isn't necessarily linear with RPM, but they can run out of steam pretty quick compared to the other two.
Centrifugal superchargers start off slow and increase boost almost linearly with RPM. As RPM climbs, so does boost. Boost will almost never 'flatten' out with a centrifugal.
Turbos must be setup according to how you want to drive. Most people on here seem to want to throw a huge 88-91mm turbo at a 5.3. These are good for 1000+ HP and won't spool up until 4K rpm. A tiny turbo capable of making 500 HP would hit boost as fast as you could push the pedal down, similar to a roots blower. Once turbos spin up fast enough to build boost, the boost will climb VERY quickly to its maximum preset and then level off. Head flow, cam size, etc will have an impact on what boost does once it hits that preset.
Centrifugal superchargers start off slow and increase boost almost linearly with RPM. As RPM climbs, so does boost. Boost will almost never 'flatten' out with a centrifugal.
Turbos must be setup according to how you want to drive. Most people on here seem to want to throw a huge 88-91mm turbo at a 5.3. These are good for 1000+ HP and won't spool up until 4K rpm. A tiny turbo capable of making 500 HP would hit boost as fast as you could push the pedal down, similar to a roots blower. Once turbos spin up fast enough to build boost, the boost will climb VERY quickly to its maximum preset and then level off. Head flow, cam size, etc will have an impact on what boost does once it hits that preset.
10-22-2013, 10:44 PM
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Heads dont really matter much when your forcing air thru them...A s475 turbo spools just fine on a 5.3 with a cam that has a smaller exhuast duration then the intake so there isnt wasted exhuast when the valves open. Foot braking my car with a th400 and 3000 stall im getting a 1.47 60ft and it spool fairly fast. A larger hot side is how you make the power. Ive seen lots of 5.3s make low power cause of small turbos. Currently mine is making 633whp at 13lbs stock 5.3 comp turbo cam and pro flow intake.