176?
That's sad.

I got a tune a local Kouki FC with one of those Buick(?) SC's, and we managed to get a little over 190+ hp at the wheels on a DynoJet.


-Ted

 

Codeblue saw 210 rwhp on a streetported 13b and a 7" camden

 

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)

 

that buick blower you are refering to is the M90. At best it see's efficiency of about 55-60% if you get the ariflow and pressure ratio JUST right. Otherwise it blows a lot of hot air.


BC

 

I cant speak for larger blowers, but the 3rd gen M90 off a grand prix takes about 50 hp to turn at 14000 rpm. Its significant.

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

 

I don't know much about superchargers, as evidenced by my post. Though the points about cost effective and such are valid.

Yes, an unmodified 13B will handle 30 PSI of boost...once.

Is there proof that is due only to the supercharger, or is it because the engine is running a better tune?

Keep in mind that the 3rd rotor is not "dead weight" and adds a significant amount of torque over a 13B.

Turbo lag is a myth. When you are taking about the stock turbo or a properly sized aftermarket turbo boost is instant.

If that's the case then there is something seriously wrong with that setup. Either the turbo is too large, there is a restriction somewhere, or the A/F ratio is way too rich (which is quite common).

It's common to see 15-25 PSI in pre turbine pressure. This drops when the wastegate opens to around 9-15 PSI.

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.

Yep. It kills me when people say "a turbo is free power".

 

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

 

[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

 

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

 

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

 

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