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To avoid completely hijacking Therock88's Meth thread I started this to continue a side discussion on use of the larger TVS2650 supercharger on the AJ133 (supercharged 5.0 V8). The original thread is here: https://www.jaguarforums.com/forum/f...3/#post2309758
For continuity sake I will include the first posts that started the conversation:
Originally Posted by SinF
A larger SC without upgraded cooling will be just getting to heat soaking much sooner. So unless you are stacking dry ice prior to each pull, it won't be a good mod.
Originally Posted by FLRRS
As the TVS2650 is more efficient at the range we are targeting and provides greater mass air flow at a lower temperature there is a reduction in the need for charge air cooling to achieve higher power levels with the same boost levels. The 2650 is rated at 3377 kg/hr compared to 2414 kg/hr at a pressure ratio of 1 (14.7 psi of boost). That's a huge difference in mass air flow.
Naturally greater charge air cooling is a benefit in almost all conditions if there are no trade offs (increase pressure loss due to a more restrictive intercooler core for example) but in our application yes, a larger more efficient supercharger will be a benefit even without any increase in charge air cooling capability.
If you use a more efficient charger at the same power level the engine will actually be cooler additionally, the more efficient charger will also allow higher power levels that are not possible with the factory one.
To explain it in simpler terms a road racer could run cooler at the same power levels with the factory charger air cooler and the 2650 and those that drag race could run at higher power levels as the heat soak issue it not as significant of a issue with time between runs to cool down.
Thank you for attempting to explain this to me. I read linked article.
I understand "more efficient" part, I get "greater mass air flow" but I still don't understand "at a lower temperature". Supercharger is compressor, it takes volume of air at one pressure applies mechanical energy that produces smaller volume of air at higher pressure. This will always result in heat and my understanding of fluid thermodynamics is that the same change in pressure will always result in the same amount of generated heat unless you change gas composition.
My understanding that at the same altitude, humidity and ambient temperature 14.7 psi of boost will produce the same amount of heat regardless of what SC you use.
Please explain to me how does TVS2650 gets around Charle's law? Here is accessible article that explains air compression process in more detail.
No problem. The TVS 2650 does not get around Charles law. Charles law states even in a perfect world of 100% efficiency when you compress air the temperature will increase. As no 100% efficient superchargers exist they all add heat while compressing the air in addition to the heat generated under the ideal conditions of 100% efficiency. The TVS 2650 simply adds less heat for a given volume of mass air moved.
Your second statement " My understanding that at the same altitude, humidity and ambient temperature 14.7 psi of boost will produce the same amount of heat regardless of what SC you use." is incorrect. A supercharger with lower efficiency (in our case the TVS 1900) will add more additional heat on top of Charles law compared to the more efficient Supercharger (the TVS 2650).
The TVS 2650 is moving an additional 39.7% air with each rotation less working the air less and adding less heat. Additionally the TVS 2650 was developed after the TVS 1900 and has several additional features such as an 10 degree increase in rotor twist further increasing the advantage.
The TVS 2650 does not get around Charles law. Charles law states even in a perfect world of 100% efficiency when you compress air the temperature will increase. As no 100% efficient superchargers exist they all add heat while compressing the air in addition to the heat generated under the ideal conditions of 100% efficiency. The TVS 2650 simply adds less heat for a given volume of mass air moved. The TVS 2650 is moving an additional 39.7% air with each rotation less working the air less and adding less heat.
I understand now - total heat generated is X from compression + Y from mechanical operation of supercharger. While X is always constant, you can reduce Y by building a better SC. Do you know what percentage of heat X relative to Y? "39.7% air with each rotation" could not mean "39.7% less heat" (i.e X is not zero).
Formulas for calculating heat from supercharging that I have found don't have anything that I can recognize as Y. I did find some articles suggesting that Centrifugal, TVS and Twin Screw generate different amount of heat as measured by discharge temperature at the same boost. However, here we are talking TVS vs TVS.
Do you have discharge temperature numbers for both at the same boost level?
I understand now - total heat generated is X from compression + Y from mechanical operation of supercharger. While X is always constant, you can reduce Y by building a better SC. Do you know what percentage of heat X relative to Y? "39.7% air with each rotation" could not mean "39.7% less heat" (i.e X is not zero).
Formulas for calculating heat from supercharging that I have found don't have anything that I can recognize as Y. I did find some articles suggesting that Centrifugal, TVS and Twin Screw generate different amount of heat as measured by discharge temperature at the same boost. However, here we are talking TVS vs TVS.
Do you have discharge temperature numbers for both at the same boost level?
Exactly. That's a great way of laying it out.
I find the TVS series interesting because it is almost a hybrid between the twin screw and the roots style.
Sadly no. I grew up on turbos and they have excellent compressor maps and tons of data that spell it out but superchargers don't have nearly the documentation that turbos do. Mainly due to there are far few choices in superchargers than turbos. There are compressor maps for the TVS 1900 and 2650 on their web site and we can make some inferences from them but nothing exact. Maybe Tuning@VelocityAP can chime in with any data they may wish to share... .
Based on what they have available:
The AJ133 runs 11.6 psi from factory which is a pressure ratio (PR) of 1.78 (11.6 psi + 14.7 psia (pounds per square inch absolute also called atmospheric pressure or "Gods boost") = 26.7 psia / 14.7 psia = 1.78) but wait there's more! In reality there's restrictions in front of the supercharger so it probably loses a pisa or two so its more like a PR of 1.82 or so. Knowing that we can find it on the compressor map and draw a line across:
I also looked at that graphs ( I think the one you posted is for TVS 1900), but my understanding of kW figures (i.e. 50 to 56 kW) is that it is energy that takes to drive SC. As SC is not 0% efficient, only some of it will go into production of heat. According to graph, we are looking at 60-70% efficiency in the most of the range. Even if we know SC efficiency, waste (1 - efficiency) is not entirely heat - some of it will be noise and vibrations. Also as SC itself radiates heat, the calculation to even approximate outlet temperature based on energy it takes to drive is going to be immensely complex.
I also noted that TVS 2650 at 1.8 corresponds to 70 to 78kW in 55 to 60% zone and TVS 1900 at 1.8 corresponds to 50 to 56kW in 60 to 65% zone. This tells me TVS 1900 is more efficient in intended application (both energy to drive it and operational efficiency). This means you would have to increase boost just to end up where TVS 1900 is. Am I misreading the graph?
I also looked at that graph, but my understanding of kW figures (i.e. 50 to 56 kW) is that it is energy that takes to drive SC. As SC is not 0% efficient, only some of it will go into production of heat. Even if we know SC efficiency, waste (1 - efficiency) is not entirely heat - some of it will be noise and vibrations. Also as SC itself radiates heat, the calculation to even approximate outlet temperature based on energy it takes to drive is going to be immensely complex.
Exactly, as we don't have the resources or data the best we can do is make educated guesses until someone (Velocity AP cough, cough) bolts one on and tests it. Here on the TVS map you can see its actually not as good at higher PR but man does it flow volume! The TVS 2650 is really a unit designed for the aftermarket and has a bunch of "hot rodder" tweaks that are commonly done to superchargers by aftermarket companies. Like larger bearings and timing gear as well as the pressure relief ports in bearing plate for reduced input power.
Kong performance makes monster 2650 kits for the newer LSA/LS9 and LT Chevy engines https://kongperformance.com/
I am 100% on board with "bigger is better", as long as you can keep it cool. You don't ever want to hear that ping-bong coming from your engine, that is the sound money makes as it goes down the drain.
My understanding of the issue with F-type and AJ133 /126 is that they are limited by cooling. JLR is "right sized" intercooler, and most of what VAP was doing with their tuning results in heat soak. Great for quarter mile, not so much for a race track.
I also noted that TVS 2650 at 1.8 corresponds to 70 to 78kW in 55 to 60% zone and TVS 1900 at 1.8 corresponds to 50 to 56kW in 60 to 65% zone. This tells me TVS 1900 is more efficient in intended application (both energy to drive it and operational efficiency). This means you would have to increase boost just to end up where TVS 1900 is. Am I misreading the graph?
No you are not. As Jaguar did select the best unit for the intended application. However we are after higher power thus increasing the PR. The lower pulley mod that is very popular adds 3.5 psi and changes the PR to 2.0. In that situation the TVS 2650 starts becoming the better choice. If someone wants to keep the stock power it would not be worth the money spent on a new supercharger. This is why you can't just install the biggest supercharger that will fit for every application. However if they are looking for more power the 2650 can do it more efficiently. Also it will open the door to even higher power levels
I am 100% on board with "bigger is better", as long as you can keep it cool. You don't ever want to hear that ping-bong coming from your engine, that is the sound money makes as it goes down the drain.
My understanding of the issue with F-type and AJ133 /126 is that they are limited by cooling. JLR is "right sized" intercooler, and most of what VAP was doing with their tuning results in heat soak. Great for quarter mile, not so much for a race track.
Agreed. There are two camps here the road race and street/drag race camp. For road racing I feel there will be limited application for this mod as the skill level needed to take advantage the gains offered would be a limiting factor. This is mainly aimed at street and drag race applications. As the cars age out to second and third generation owners this will be the most common usage due to the high cost of road racing the vehicle.
This discussion was a great opportunity to learn more about superchargers. I appreciate time you spent answering my questions.
Originally Posted by FLRRS
Originally Posted by SinF
I also noted that TVS 2650 at 1.8 corresponds to 70 to 78kW in 55 to 60% zone and TVS 1900 at 1.8 corresponds to 50 to 56kW in 60 to 65% zone. This tells me TVS 1900 is more efficient in intended application (both energy to drive it and operational efficiency). This means you would have to increase boost just to end up where TVS 1900 is. Am I misreading the graph?
No you are not. As Jaguar did select the best unit for the intended application. However we are after higher power thus increasing the PR. The lower pulley mod that is very popular adds 3.5 psi and changes the PR to 2.0. In that situation the TVS 2650 starts becoming the better choice. If someone wants to keep the stock power it would not be worth the money spent on a new supercharger. This is why you can't just install the biggest supercharger that will fit for every application. However if they are looking for more power the 2650 can do it more efficiently. Also it will open the door to even higher power levels
Could it also be the case that your statement "As the TVS2650 is more efficient at the range we are targeting" is not quite accurate?
Unfortunately, I still fail to understand why you think bigger supercharger would run cooler at the same or greater boost levels.
I also noted that TVS 2650 at 1.8 corresponds to 70 to 78kW in 55 to 60% zone and TVS 1900 at 1.8 corresponds to 50 to 56kW in 60 to 65% zone.
Approximately 20KW difference it takes to drive TVS 2650 vs TVS 1900 means that everything else equal, you will be approximately 25 HP behind after doing the swap - it takes more power to drive bigger supercharger.
Last edited by SinF; Oct 31, 2020 at 01:14 PM.
Reason: I did not notice difference in mass flow rate scales, these numbers are not at the same mass flow rate.
Interesting discussion so far. However, are either of you looking at the graphs with respect to the required flow rates to achieve the desired hp? If I'm not mistaken (could be) a flow rate of about 2000kg/hr is required to support ~650hp (about 1.5 cfm/hp* and ~190kg/hr flow/100 cfm**)? In view of this one of your views might change.
*According to Kenne Bell
** From a conversion chart
Yes, TVS 2650 at 2000kg/hr flow rate is more efficient, however I am not sure you could get to that mass flow rate without increasing boost (and pressure ratio). So the horizontal red line (stock numbers) goes up. So total heat generated X from compression goes up.
I think you would likely port and polish intake at the point ... so no idea how to tell what it going to be at.
This discussion was a great opportunity to learn more about superchargers. I appreciate time you spent answering my questions.
Could it also be the case that your statement "As the TVS2650 is more efficient at the range we are targeting" is not quite accurate?
Unfortunately, I still fail to understand why you think bigger supercharger would run cooler at the same or greater boost levels.
Originally Posted by SinF
Approximately 20KW difference it takes to drive TVS 2650 vs TVS 1900 means that everything else equal, you will be approximately 25 HP behind after doing the swap - it takes more power to drive bigger supercharger.
It comes down to use case. What I meant by "range we are targeting" is no one is going spend a couple grand on a supercharger upgrade to run the stock boost/power levels that the TVS 1900 is a better fit for. This is for individuals looking to achieve at least the 650hp the TVS 1900 runs out of steam at. At 650 HP and above the TVS 2650 will be much more efficient. To clarify at 650hp and above the TVS 2650 charge air temp will be lower then the TVS 1900 as it is at its limits.
Originally Posted by RGPV6S
Interesting discussion so far. However, are either of you looking at the graphs with respect to the required flow rates to achieve the desired hp? If I'm not mistaken (could be) a flow rate of about 2000kg/hr is required to support ~650hp (about 1.5 cfm/hp* and ~190kg/hr flow/100 cfm**)? In view of this one of your views might change.
*According to Kenne Bell
** From a conversion chart
You are correct and why the TVS 2650 will be the better unit for those looking to go beyond the 650hp that is the upper limit for the TVS 1900 on the AJ133. You can beat a few more horses out of the 1900 but it is becoming a heat pump very quickly as you are nearly off the compressor map and beyond the manufacture 18,000 rpm limit. To move that much air the TVS 2650 is just getting to work. Chevrolet LS9's are making over 1000 whp with the unit. Not apples to apples but indicates what it's capabilities are.
It comes down to use case. What I meant by "range we are targeting" is no one is going spend a couple grand on a supercharger upgrade to run the stock boost/power levels that the TVS 1900 is a better fit for. This is for individuals looking to achieve at least the 650hp the TVS 1900 runs out of steam at. At 650 HP and above the TVS 2650 will be much more efficient.
Chevrolet LS9's are making over 1000 whp with the unit. Not apples to apples but indicates what it's capabilities are.
Now, I am way out of my competence zone... so just asking...
Isn't LS intake and heads design, that is possible because it is a pushrod engine and you have more room, what allows this power level? My WAG that you don't have room under the hood in F-type to fit better flowing heads and larger supercharger to get to that level unless you cut the hood.
Now, I am way out of my competence zone... so just asking...
Isn't LS intake and heads design, that is possible because it is a pushrod engine and you have more room, what allows this power level? My WAG that you don't have room under the hood in F-type to fit better flowing heads and larger supercharger to get to that level unless you cut the hood.
Something like this (Roadkill's Draguar) :
Lol I remember that thing. It had a actual old school roots blower on it. With how much power can be made by the newer compact twisted lobe blowers there's no need for cutting the hood unless you just want to.
The biggest factor is that the LS9 is a 6.2 liter compared to our 5.0 so it will always be easier for them to make more power. Plus the decade of advancements that have happened since the AJ133 debuted in 2009. When the AJ133 came out with direct injection and overhead cams it was amazing. Now its solid mid pack for the upper level of performance V8s.
You could port our heads but they are pretty good already so there are easier gains with boost to be had. The 2650 is the same height as ours it's just 40mm longer for the increase in displacement to take it from 1.9 liters to 2.65 liters so no need to cut the hood for this one. I'd say the real limiting factor for development of this engine is the lack of internal parts for it. To "build" the bottom end it would be a very expensive custom effort. I don't know of anyone that has done it. I could build the bottom end of my GTR to handle 1200 whp for under 10k with parts that are kept in stock. That's not the case here.
I could build the bottom end of my GTR to handle 1200 whp for under 10k with parts that are kept in stock. That's not the case here.
I read somewhere that JLR gave up balancing crankshafts in AJ to cut cost. Not sure how true it is...
If I was shopping based on aftermarket availability or ease of hitting crazy power levels I would probably get Mustang GT350 or Camaro SS. I think GTR is still too expensive even well-used and that eats too much into your total project budget.
If that was my goal, I definitely would not have picked F-type as a starting point, as aftermarket simply not there and the base car price is still too expensive. More so, what mods are available are often downright detrimental to long-term reliability.
So if your goal is to hit 650+ hp, absolutely TVS 2650 will get you there, but why put it on AJ133? LS or Coyote would get you there today and cheaper.
TVS2650 discussion
