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Radix---displacement vs effciency?


slowfive0
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Ok, I think everyone would agree that 6.0 is about the biggest this blower can handle. A radix just isn't a good match for a 408. My question is:

If a camshaft helps a radix combo, wouldn't ported or better cylinder heads help also?

I'm at 190,000 miles and am replacing my motor with a 38,000 mile LQ9. I want to put better rod bolts in it and a better cam. I really want to get this truck in the 11's bad.

In my my mind porting the heads would help this cause, but some say no. So, if a cam helps, why wouldn't a ported cylinder head help?

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The radix is a great blower but one of the biggest reasons it has trouble is due to its poor design with the heat transfer when using smaller pulleys below the 3"... There are a few people that can get there trucks in the 11's and low 11's with this blower but it will require the use of meth or nitrous as well as a bigger intercooler resovoir... Supersub makes a phenolic spacer that does wonders with this blower by keeping the engine block heat from transfering to the blower... With the proper measures taken to reduce the heat you can run smaller pulleys like a 2.8 or 2.75" and get 9-11PSI out of it... If you can get the radix to operate at ambiant IAT's it is a awesome blower still... I myself am running the blower but am battling high IAT's and will be using meth to help counter act them as well as purchasing the phenolic spacer next spring hopefully...

 

As far as rod bolts, it is not all that necessary unless your reving out more than 7k rpms but at the same time it is still good insurance... I beleive idahoBLKss was hiting low 11's and running 22PSI of boost on a stock block,crank,heads,cam ect.. It's all in the tune and good fuel...

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It's all about diminishing returns... for the same amount of $$$ that you would spend getting a decent 10-11 psi out of a Radix-equipped LQ9, you could put into a turbo or large centrifugal and get 15-psi or more. My point is, the Radix has it's limits, and your performance expectations (low-11s) are realistically beyond those limits.

 

Air is 'stretchy stuff', and yes anything that helps a motor N/A also helps it under forced induction. So reworking heads/cam is never a bad idea, although it might not get you the ET gains you were hoping for. The problem is that usually the heads/cam are not the chokepoint, the compressor itself is!

 

Mr. P. :)

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777 has a Radix on top a 408, he has made some good #s

Like I stated, It is a perfectly fine blower if you spend the $$$ to get that heat pump to be more efficient... But like Mr. P said you would be almost better off spending the money on a different blower... Unlike me who bought a $5500 dollar blower for $4200 brand new from magnusen and put a 90mm TB and modified the J-tube to 90mm and added meth I still need to buy a spacer from ray and get a bigger resevoir for my coolant... Wouldn't hurt getting a bigger intercooler too... All said and done $250 for meth, $450 spacer, $200 for resevoir, 90mm TB $150 and fabrication of J-tube free, Smaller pulley $75... about $1125 to get the MP112 to perform as efficient as possible at ambiant temps instead of 200' IAT's LOL.... So if you already have the heat pump radix and don't want to drop 3-4K more on a newer TVS because a used MP112 would only fetch ya about 3K I would not mind dumping an extra grand to keep the exsisiting radix as long as you're not planning low 11's or 10's 1/4's... But mid to high 11's should not be a problem at all... BTW if you want low 11's with the radix a 75 shot of NAWWWS and the IAT mods will get ya there LOL

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  • 3 weeks later...

It's all about diminishing returns... for the same amount of $$$ that you would spend getting a decent 10-11 psi out of a Radix-equipped LQ9, you could put into a turbo or large centrifugal and get 15-psi or more. My point is, the Radix has it's limits, and your performance expectations (low-11s) are realistically beyond those limits.

 

Air is 'stretchy stuff', and yes anything that helps a motor N/A also helps it under forced induction. So reworking heads/cam is never a bad idea, although it might not get you the ET gains you were hoping for. The problem is that usually the heads/cam are not the chokepoint, the compressor itself is!

 

Mr. P. :)

 

Well said Steve :thumbs: . the radix will see a truck into the low 12s / high 11s without n20 or meth comfortably (also highly dependent on the tuner). after that you will be pushing the envelope

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  • 2 weeks later...

I have a question (and instead of a new topic, I figured I ask here because this kinda falls in line with mine) I want to put a smaller pully on my truck, running a 3.3" pully now on my Radix MP112, I'd like to drop to a 3.0" or a 2.9" I'll be running a Snow meth kit soon, but was wondering if the motor would take the added PSI? one guy at work says it'll blow my motor to pieces.

 

I have almost 100,000 miles on my motor now. you guys are my fall back becasue most of you have delt with these issues.

 

also what is the price of that spacer? I've seen photos and I like them alot, and want to get one when I upgrade the throttle body

 

*Nevermind, saw the price of the spacer above, lol*

Edited by Bad Company
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I want to put a smaller pully on my truck, running a 3.3" pully now on my Radix MP112, I'd like to drop to a 3.0" or a 2.9" I'll be running a Snow meth kit soon, but was wondering if the motor would take the added PSI? one guy at work says it'll blow my motor to pieces.

LMAO :crackup: .... No pulleying down won't blow your motor to pieces LOL... The guy at work must be on crack or knows nothing about these indestructable LQ9 iron blocks LOL.... I myself still have a stock bottom end running about 9.5-10lbs of boost on a 2.8" pulley... I also have my compression bumped up to by milling my stock heads to 10.5-1 and a aftermarket camshaft, with a devils own meth kit for the IATS and I haven't blown it up or even come close... IdahoBlkSS ran 22PSI of boost on a completley stock engine and never blew it up... It's all in the tune bud... I'd run nothing less than a 2.9 unless you have some things in place to eliminate IATS such as a bigger coolant resovoir, bigger intercooler, meth injection etc... A 2.9-3.0" pulley would be about 8-9PSI which is not alot to worry about... The first thing I did when I bought my MP112 was put a 3.0" on it and had Wheatley send me a custom tune for it...

 

FYI-- Check out my sig... It has just about all the stuff I have done to the truck and all on a Stock Bottom End... Your will love the boost just fine... If you had closer to 200k I might say to maybe play it a little safer but I still would do it LOL...

Edited by 2003_SuperSport
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awesome deal that puts me in a happy place. I think he was talking about his car for the most part which is an 03 Cobra and he's had a lot of issues with pullys and stuff like that. I dunno. Anyways sounds good and yeah I'm buy a snow method kit next week and I would like to get a smaller pulley on my truck got a 2013 Mustang GT to stomp

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Do it. It will love you for it - lol! I have 190,000 miles on mine and have a 2.8 pulley on it. Been a best of 12.20 at 110 with it at 5650 (I'm almost 300lbs & all of my stereo equip, etc). Stock wheels, tailgate, etc. Been an amazing daily driver for me. Good tune is where its at. Good luck!

 


 

I have a question (and instead of a new topic, I figured I ask here because this kinda falls in line with mine) I want to put a smaller pully on my truck, running a 3.3" pully now on my Radix MP112, I'd like to drop to a 3.0" or a 2.9" I'll be running a Snow meth kit soon, but was wondering if the motor would take the added PSI? one guy at work says it'll blow my motor to pieces.

 

I have almost 100,000 miles on my motor now. you guys are my fall back becasue most of you have delt with these issues.

 

also what is the price of that spacer? I've seen photos and I like them alot, and want to get one when I upgrade the throttle body

 

*Nevermind, saw the price of the spacer above, lol*

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