Turbocharged vs supercharged

[DarkPira7e]

Originally Posted by Calum

Gotta be honest, I find that really hard to believe. A turbo should be noticeably more power, with the same level of tune and octane, when compared to a super charger.

Power does not come from boost. You can put 20psi through this engine and make shit power. Timing and fueling command power output ultimately- he could have his lambda fat to aid with cooling slightly, which will diminish output.

It's called tuning because you're adjusting with a goal in mind; just that most people tune to make the most power, where Mike has tuned for safety and the torque curve that yields him comfort on track

[Irace86.2.0]

Originally Posted by Calum

Gotta be honest, I find that really hard to believe. A turbo should be noticeably more power, with the same level of tune and octane, when compared to a super charger.

Just to add to what Mike said:

The TVS 1320 is listed on Eaton's website as ideal for 3.0-4.5L engines. My wife's Audi Q5 uses the same Eaton TVS1320, and it is a 3.0L V6. Cosworth uses the TVS 900 on the FA20. The point is the supercharger is relatively large for this platform and really doesn't hit its stride until higher boost levels. While torque does slightly drop off, the hp continues to rise to redline. Below is a Harrop kit on E85 at a bar of boost.



https://www.eaton.com/us/en-us/catal...tvs-r1320.html

The JRSC is as you know a centrifugal supercharger, so it'll be building more on the top end. If you get the C38 or don't max out the C30 then it should pull to redline and not drop off. The C30 is at 96% of max on the high boost pulley. See below.



For this A90 Supra example, the stock turbo is small, so torque rises very fast and then it falls off, as the turbo is likely restricting the engine. Lots of torque down low, but not a whole lot of peak horsepower. In fact, peak hp is less than peak torque. Add a larger turbo in the next graph, and we get some rpm delay before torque hits due to boost threshold and the torque curve looks more flat with a power curve that pulls more to redline. Now, peak horsepower is more than torque. Add an even larger turbo and the boost threshold is significant, so the curve starts looking like a JRSC curve where torque takes time to ramp up, and it would look even more like one if they didn't limit boost there.

I don't know what Mike is doing, but it is entirely possible to design a system where the turbo makes peak torque down low, but falls off, such that it hits the same peak boost of 9psi as a supercharger, but it does 9 psi at 4k vs 7k, so the supercharger has the same or even more peak horsepower because they are making more torque at higher rpms, yet the turbo might have more area under the curve, especially down low.

[Calum]

Originally Posted by CSG Mike

It's simple physics.

- small turbo, so small it's maxed out, and doesn't actually need a wastegate to run safely
- maxed out turbo = out of efficiency island, vs say, a TVS1320 which is in the meat of its powerband
- known data that on a FA20: Whether JRSC, Edelbrock, or TVS, on 91, they make the same power whether you're seeing 9psi or 12 psi

- to supplement my maxed out turbo, I also run a giant giant Garrett intercooler rated for more than double what I need, complete with ducting
- If you saw my pre-intercooler charge temps, you'd probably shit your pants

- I make no more power going higher than 7psi on a 91 octane map, due to diminishing returns on boost vs iat vs octane, so my 91 map peaks at 7 psi. My 91 map at 7 psi (or 10.5 psi if you want to get technical) makes roughly the same power as a JRSC/Edelbrock/Harrop on their standard pulleys.

You're welcome to extrapolate my power using videos.

Delete please

[Calum]

Originally Posted by CSG Mike

It's simple physics.

- small turbo, so small it's maxed out, and doesn't actually need a wastegate to run safely
- maxed out turbo = out of efficiency island, vs say, a TVS1320 which is in the meat of its powerband
- known data that on a FA20: Whether JRSC, Edelbrock, or TVS, on 91, they make the same power whether you're seeing 9psi or 12 psi

- to supplement my maxed out turbo, I also run a giant giant Garrett intercooler rated for more than double what I need, complete with ducting
- If you saw my pre-intercooler charge temps, you'd probably shit your pants

- I make no more power going higher than 7psi on a 91 octane map, due to diminishing returns on boost vs iat vs octane, so my 91 map peaks at 7 psi. My 91 map at 7 psi (or 10.5 psi if you want to get technical) makes roughly the same power as a JRSC/Edelbrock/Harrop on their standard pulleys.

You're welcome to extrapolate my power using videos.

Ok, so am I understanding correctly? The issue isn't that the engine can't reliably make more power with a properly sized turbo than a supercharger, the issue is that you're using a turbo that's too small for the increased efficiency of a turbo to be reveled?

Why did you spend so much money/time/fabrication to get more air through a huge intercooler instead of upgrading to a larger and/or more efficient turbo?

[jflogerzi]

Originally Posted by Calum

Ok, so am I understanding correctly? The issue isn't that the engine can't reliably make more power with a properly sized turbo than a supercharger, the issue is that you're using a turbo that's too small for the increased efficiency of a turbo to be reveled?

Why did you spend so much money/time/fabrication to get more air through a huge intercooler instead of upgrading to a larger and/or more efficient turbo?

Heat management, predictable power curve, engine longevity, and sure other reasons

Sent from my GM1915 using Tapatalk

[CSG Mike]

Originally Posted by Calum

Ok, so am I understanding correctly? The issue isn't that the engine can't reliably make more power with a properly sized turbo than a supercharger, the issue is that you're using a turbo that's too small for the increased efficiency of a turbo to be reveled?

Why did you spend so much money/time/fabrication to get more air through a huge intercooler instead of upgrading to a larger and/or more efficient turbo?

Because with the current setup, I literally, cannot overboost. Stuck wastegate? no problem. Wastegate failure? no problem. My goal is reliability and sustainability, not pure output.

Enabling more power and/or efficiency is just a matter of swapping on a larger turbo, but why? I can't use any of that extra efficiency/overhead without going back into constantly-breaking-transmissions territory.

I don't care to total my car with a CD009 swap, and don't care to swap in a PPG gearset.

If I just want more power, there are other more powerful cars I can drive.


At the end of the day, I went turbo because I wanted to prove that a turbo setup can be done reliably. It just so happens a supercharger can put out just as much power at roughly half the cost.

Modern superchargers are far more efficient than I think you may give them credit for.

[new2subaru]

Originally Posted by CSG Mike

Because with the current setup, I literally, cannot overboost. Stuck wastegate? no problem. Wastegate failure? no problem. My goal is reliability and sustainability, not pure output.

Enabling more power and/or efficiency is just a matter of swapping on a larger turbo, but why? I can't use any of that extra efficiency/overhead without going back into constantly-breaking-transmissions territory.

I don't care to total my car with a CD009 swap, and don't care to swap in a PPG gearset.

If I just want more power, there are other more powerful cars I can drive.


At the end of the day, I went turbo because I wanted to prove that a turbo setup can be done reliably. It just so happens a supercharger can put out just as much power at roughly half the cost.

Modern superchargers are far more efficient than I think you may give them credit for.

I think people will be parroting this for some time to come.

[86TOYO2k17]

Originally Posted by CSG Mike

I can't use any of that extra efficiency/overhead without going back into constantly-breaking-transmissions territory.

I don't care to total my car with a CD009 swap, and don't care to swap in a PPG gearset.

It just so happens a supercharger can put out just as much power at roughly half the cost for a track build.

It’s a good thing OP has an auto to handle all the power then.

Finished that last statement for you.

[CSG Mike]

Originally Posted by 86TOYO2k17

It’s a good thing OP has an auto to handle all the power then.

Finished that last statement for you.

Don't lose sight of everything else, because holding the power is what you're focused on.

I should mention, 5 of the 7 transmissions i shredded died on the street, not on track.

[Irace86.2.0]

Originally Posted by Calum

Ok, so am I understanding correctly? The issue isn't that the engine can't reliably make more power with a properly sized turbo than a supercharger, the issue is that you're using a turbo that's too small for the increased efficiency of a turbo to be reveled?

Why did you spend so much money/time/fabrication to get more air through a huge intercooler instead of upgrading to a larger and/or more efficient turbo?

Mike’s turbo. Clearly he is not trying to overcompensate:

[Irace86.2.0]

Originally Posted by CSG Mike

Because with the current setup, I literally, cannot overboost. Stuck wastegate? no problem. Wastegate failure? no problem. My goal is reliability and sustainability, not pure output.

Enabling more power and/or efficiency is just a matter of swapping on a larger turbo, but why? I can't use any of that extra efficiency/overhead without going back into constantly-breaking-transmissions territory.

I don't care to total my car with a CD009 swap, and don't care to swap in a PPG gearset.

If I just want more power, there are other more powerful cars I can drive.


At the end of the day, I went turbo because I wanted to prove that a turbo setup can be done reliably. It just so happens a supercharger can put out just as much power at roughly half the cost.

Modern superchargers are far more efficient than I think you may give them credit for.

Really though, what turbo do you have on your car? It must be super small to have such a low max boost. It seems like such a small turbo would spool super fast like the A90 Supra's torque curve to 7 psi then plateau before seeing some boost creep as the engine muscled more boost out of the turbo up to 10 psi, but even then, the turbo would have to be a major restrictor and cause some back pressure. Are you just getting huge boost drop because of your giant FMIC? Or are you using a permanent restrictor plate or small bypass system to limit flow to the turbo?

I'm trying to wrap my head around how a small turbo could be so small as to max out on boost, but not choke the engine while naturally creating a ramp up without a boost controller. Are you using drive-by-wire to limit throttle input?

[CSG Mike]

Originally Posted by Irace86.2.0

Really though, what turbo do you have on your car? It must be super small to have such a low max boost. It seems like such a small turbo would spool super fast like the A90 Supra's torque curve to 7 psi then plateau before seeing some boost creep as the engine muscled more boost out of the turbo up to 10 psi, but even then, the turbo would have to be a major restrictor and cause some back pressure. Are you just getting huge boost drop because of your giant FMIC? Or are you using a permanent restrictor plate or small bypass system to limit flow to the turbo?

I'm trying to wrap my head around how a small turbo could be so small as to max out on boost, but not choke the engine while naturally creating a ramp up without a boost controller. Are you using drive-by-wire to limit throttle input?

18G

Specifically a GReddy T518Z

The FMIC doesn't cause any boost drop; the Garrett FMIC actually increased flow.

The turbo has a giant hot side, with a relatively small cold side. Your picture above isn't too far off from the actual size of the cold side.

I think most folks have a good idea of the size of the OEM throttle body diameter. Use that as a frame of reference compared to the turbo. In particular, look at the outlet size of the turbo. It's smaller than the outlet of a Rotrex C30-94. https://www.instagram.com/p/BbYKuqwhwzB/

[DarkPira7e]

Originally Posted by CSG Mike

18G

Specifically a GReddy T518Z

The FMIC doesn't cause any boost drop; the Garrett FMIC actually increased flow.

The turbo has a giant hot side, with a relatively small cold side. Your picture above isn't too far off from the actual size of the cold side.

I think most folks have a good idea of the size of the OEM throttle body diameter. Use that as a frame of reference compared to the turbo. In particular, look at the outlet size of the turbo. It's smaller than the outlet of a Rotrex C30-94. https://www.instagram.com/p/BbYKuqwhwzB/

I think if some people saw the compressor wheel and exhaust wheels on these turbos compared to what most people run, it'd give them a better idea.
Sometimes I look at one of my 9B turbos I have on a shelf from my VR4 and suddenly everything looks like it should be sucking rags off of nearby shelves.

[mrg666]

Originally Posted by CSG Mike

Don't lose sight of everything else, because holding the power is what you're focused on.

I should mention, 5 of the 7 transmissions i shredded died on the street, not on track.

Rods could have bent if the transmission had not failed first, especially if you had no proper cooling.