Supercharged drag RX7 2nd ge.
#28
putting it down daily
https://www.rx7club.com/2nd-generation-specific-1986-1992-17/230-whp-supercharged-vert-complete-dyno-car-video-sc-comparisons-431570/
a local guy with a setup very similar to mine (I have yet to dyno, so I will let his post do the talking)
a local guy with a setup very similar to mine (I have yet to dyno, so I will let his post do the talking)
#29
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BC
#30
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One thing I've always assumed is that if you get a good sized roots style blower on there to provide good boost down low, isn't the inertia of the blower significant to the point where it's sucking up most of power created just to spin it?
Keep in mind that I've not looked at superchargers in almost 9 years, and then only briefly.
Are there any examples of high HP 13Bs running superchargers that I could look at?
Keep in mind that I've not looked at superchargers in almost 9 years, and then only briefly.
Are there any examples of high HP 13Bs running superchargers that I could look at?
However a turbo is a gigantic restriction in the exhaust stream and, as I understand it, its impossible to have lower pre-turbine exhuast pressures than intake boost pressure. So in effect you will always have some exhaust reversion. In a low overlap engine (like the renesis or a specificly cammed piston engine) this is minimized, but on a 13b you see exhaust reversion that heats the incoming intake charge and hampers chamber filling until the exhaust port is closed. So you see a loss from the exhaust reversion and late start on filling. Is it 50hp? I am not the person to ask.
A blower has the advantage of cyclinder clearing due to higher intake pressure, scavenging, and less heating of the intake charge by exhaust reversion. I think the big thing to consider is efficiency. Both methods of FI require energy to increase power, so its a trade off either way.
BC
#31
Engine, Not Motor
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Yes, an unmodified 13B will handle 30 PSI of boost...once.
Basically a .5bar supercharger setup on a 13b would act like a NA 20b. I doubt that the supercharger has any more inertia than an additional rotor. (I do not have numbers to back this up as I have no access to rotational inertia numbers for the superchargers.)
Turbochargers also have inertia, commonly called turbo lag.
In my opinion, more AutoXers should use superchargers, as the turbo just starts to spool up as you lift your foot for the next corner.
However a turbo is a gigantic restriction in the exhaust stream and, as I understand it, its impossible to have lower pre-turbine exhuast pressures than intake boost pressure. So in effect you will always have some exhaust reversion. In a low overlap engine (like the renesis or a specificly cammed piston engine) this is minimized, but on a 13b you see exhaust reversion that heats the incoming intake charge and hampers chamber filling until the exhaust port is closed. So you see a loss from the exhaust reversion and late start on filling. Is it 50hp? I am not the person to ask.
In high overlap engines like bridgeports or peripheral ports, the backpressure seems to help out a lot in keeping the pressurized intake charge from blowing out the exhaust ports.
Both methods of FI require energy to increase power, so its a trade off either way.
BC
BC
#32
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All the backpressure does in keeping gas out of the exhaust is save fuel and keep egt's down. It does nothing for power. When you start blowing gas out the exhaust you havent hurt anythingbut your gas mileage, but what you have gained is a clean intake charge. If the intake charge is going out the exhuast then you are damn close to having zero exhaust in your combustion chamber, which means more power.
Even at 15-25 psi of backpressure there will always be more back pressure than intake pressure. Physics sucks, but you cant make energy.
BC
Even at 15-25 psi of backpressure there will always be more back pressure than intake pressure. Physics sucks, but you cant make energy.
BC
Last edited by anewconvert; 01-14-08 at 08:14 PM.
#33
Is that thing Turbo?
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[quote=Aaron Cake;7726389]If you intend to use a 13B, that's going to be a lot of time and effort (not to mention money) to run low 15s.quote]
Huh? My S4 na ran 15.2 almost completly stock except for xhaust and a cone filter. After the rest of my mods i knowi as in the 14s and everything i had including the car cost me less that 1500, with a bolt on camden kit i don't see why my car shouldn't be near 13s.
unfortunaly theres not much to back me up in way of 13s supercarched stock motor FCs. Anyway I would really love to see the proper type and size supercharger on an fc. I bet a 500hp supercharged FC with open exhaust would sound mean
Huh? My S4 na ran 15.2 almost completly stock except for xhaust and a cone filter. After the rest of my mods i knowi as in the 14s and everything i had including the car cost me less that 1500, with a bolt on camden kit i don't see why my car shouldn't be near 13s.
unfortunaly theres not much to back me up in way of 13s supercarched stock motor FCs. Anyway I would really love to see the proper type and size supercharger on an fc. I bet a 500hp supercharged FC with open exhaust would sound mean
#34
Lives on the Forum
You're right - 13-seconds from an SC 13B should be trivial.
We're only talking about 200hp at the wheels.
Building a "500hp" 13B is not...
The supercharger itself would cost more than the car, and I'd imagine the build would approach $10,000.
You got this kinda cash to waste?
-Ted
We're only talking about 200hp at the wheels.
Building a "500hp" 13B is not...
The supercharger itself would cost more than the car, and I'd imagine the build would approach $10,000.
You got this kinda cash to waste?
-Ted
#35
Is that thing Turbo?
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I don't have them money nor desire to make a 500hp SC FC. That was a seperate statement stating that i've never seen a really high HP SC FC, But i'd love too. on another not i'd love to see what my car would do with a 200whp motor seeing that i've seen 14s and have maybe 150some at the wheels
#36
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hmm the thread was about drag... Id be looking for something more like this.
20B pp SC.
http://www.aeromanagement.com.au/blown3rotor/index.html
but from what Ive read they where never happy with it.
The 20B pp now is in the process of getting 3xGt42's
20B pp SC.
http://www.aeromanagement.com.au/blown3rotor/index.html
but from what Ive read they where never happy with it.
The 20B pp now is in the process of getting 3xGt42's
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