Of course, the fuel system would have to be able to support this increase to fully take advantage of it, and to do it safely.

 

Radix + Direct Port Nitrous

 

I don't know what else can be discussed about this issue. It's already been discussed in other threads. Some people have hit just over 500rwhp some don't. The limit of the blower is around 500rwhp. Of course the vehicle driveline setup has some to do with the rwhp numbers. Autos will show less, manuals will show more, different makes may show more than us or less. Different dynos will read differently I just don't understand why it is so hard to believe that the blower has a limit around 500rwhp. The charts are there to look at and run the numbers. Every blower has it's limit and the 112(relatively small blower compared to others) is around 500rwhp.

 

I think it's significant that the owner of the fastest truck on the board initially chose a non-intercooled Whipple over an intercooled Radix, explicitly stating that the Whipple had a higher power limit....all the time praising the cleanliness of the Radix install. I think it's also significant that a respected shop can't get much more than 415/450 HP/TQ out of a Radix on a 408. Perhaps the upper limit of a Radix is best achieved on a 5.7L (or a 6.0L) motor, not a 6.7L, and perhaps the limit is right around 500 RWHP.

I think we all need to see the Radix for what it is - a great power adder, in the most complete kit available, with the cleanest install of any other F/I system on the market. But for raw power it is not the best choice out there. For that, turbo, centrifugal, or twin screw. Make no mistake - with an ATI or a Whipple or a turbo you will be fiddling around quite a bit, not bolt-on and go like with a Radix. If you are persistent, you will be rewarded. But if you don't want to fiddle and will be happy with 500 RWHP or less, it sounds like the Radix is for you.

 

After thinking about this more.
1. I think it would make sense to start with the mechanical limits of the Radix.
Everyone seems to be in agreement that it is at about 18,000rpm.
Unless there really are composite rotors out there that allow the unit to spin faster, and cooler while doing it, 18,000rpm has been a well repeated number.
2. Then we should look at the Inlet flow chart of the Radix and extend the chart in support of 18,000rpm, applying the .69 multiplication for flywheel HP.
3. Next, how do we apply the efficiancy table to the output of the Radix. Or would it be simpler/easier to not factor this in. Maybe someone has a good rule of thumb for this.
4. There should be a way to apply Nine ***** results to the power potential of the radix, how can we do this?

that's all I have so far.

 

amen brothers to the last few posts

i really thought about a forged 408 with radix and DP set up. have to run a 300+shot to do what i want to do but it would be a prety cool set up.

 

It's not hard at all to believe this. Most seem to agree, so it's probably close to right or the proverbial nail on the head!

What I thought this thread evolved into was trying to make an educated guess based on info, data, and results on what the absolute limit of the Radix might be. For ***** and giggles of course. That's what we do, right?

 

even though it has been hashed out before i will toss in my math. just guestimating from the charts 18000rpm = 1100cfm. that would be about 759fwhp. now to drive the thing would take about 90hp. that puts us at 669fwhp. now drop 18%, not really sure what number people use these days for driveline loss but that sounds good. that puts us at 548rwhp.

all of these numbers are estimates. i dont think the VE would matter, looks like it would be up there prety high even at 18000rpm. dont know how the heat would effect things.

 

There was another thread a while back where this was discussed and numbers were crunched. It got long and there has been quite a bit of discussion about this issue so forgive me if I seem kinda sensitive about it.

I will also run the numbers again tomorrow and post them here cause I can't find the other thread.

One other thing, most Cobra guys switch over to the KB when they want to get to 600rwhp(The KB blower is 27% bigger than a 112). The 112 seems to hit it's limit on those cars around 500rwhp also. I'll PM Unit and get him in here. He is the resident '03 Cobra owner and knows ALOT more about those setups than I do or probably anyone else on this site.

 

If you go back and look at the inlet flow it is more like 1000CFM at 18000rpm, maybe 1050 at the highest. It is dropping off as the rpms increase.