radix power

[hank]

i beleave when i check my pressure before it idled at 55 psi.

[6.0ss]

My 03 booster pump add on, (no in tank change) nets 49 at idle and 64lb's at WOT. Running Nelson Tune and 42lb injectors, the engine seems to give up at the end of its rpm range?? More Fuel and a tune for it?

[O3GMC]

what kinda fuel press are you radix guys getting at idle and at wide open i idle at 60lbs and wide open at around 70-72 lbs

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I'm getting about 47/65

[H2Racer]

hopefully we'll know more on this soon. we're working on fuel pressure/volume at this point.

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Hey Zippy, I've seen a similar trend with the injectors/fuel system. Everyone like to kick around the 42 lb'ers are good to "X" RWHP. Maybe in cars or two wheel drive vehicles, but the "rule" don't apply in all wheel drive where the losses are higher like the SSS and the H2. I do have a wide band and have noted the AFR creeping up at the top of the RPM band and especially in second gear. I never get to run out third and am only in third the last couple of seconds at the strip.

 

I've noticed that my truck likes to run around 11.3 to 1 AFR for best timing and power. I see the injector duty cycle maxing out at the top of the rpm band, too. I've got an 04 so I have the walbro intank pump with my kit. I don't have a fuel pressure gauge so I don't know what it going on there. With all I read a few weeks ago I decided to go ahead and buy a boost a pump. I've got it sitting on my bench ready to install just needing the time to do it.

 

I anticipate seeing the injector constant drop after I install it, but I still feel that we are indeed near the limit of what the injectors will do. I'll be sure to post my results over here, too, after the install and more wideband measurements.

 

Honestly, I can't say I blame magnacharger for only doing 42's in the kit. Think about it... if people had to cut their wiring harness and splice in new injector connectors a lot less people would buy the kit. The magnacharger is a pretty damn good "plug and play" kit with great reliability as it comes. Those who are willing to cut the harness for the most output are guys like us who just always want more

[zippy]

i'm not really sure at what point the 42's run out of fuel, but from the guys with lightning trucks that i've talked to it doesn't take much modding before the duty cycles get to the point of the injectors working very hard to try and keep up. i'm very big on not having more injector than needed since a large injector can bring on a poor idle with having the pulse width so low. at this point we're still trying to find out what it's going to take to make the numbers.

[H2Racer]

i'm not really sure at what point the 42's run out of fuel, but from the guys with lightning trucks that i've talked to it doesn't take much modding before the duty cycles get to the point of the injectors working very hard to try and keep up. i'm very big on not having more injector than needed since a large injector can bring on a poor idle with having the pulse width so low. at this point we're still trying to find out what it's going to take to make the numbers.

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Right, I'm on the same page. In my case I can be sure it's either the fuel pump or the injectors. If the boost a pump (boosting voltage to overdrive the fuel pump) can't make the walbro get it done then it must be injectors. Unless of course it's both. I sure hope that's not the case!

[MN C5]

A fair amount of Bad Info in this tread....

 

A 42lb injector will support over 600 hp with a Radix at 65lbs of pressure. I've done it more than once on a engine dyno. If you don't have enough fuel pressure at the RAIL you may have issues.

 

 

Zippy yes the Lightnings do run out of injector but they run at slightly lower fuel pressure and are putting down some big #'s with just a few mods.. In other words 42's in the Lightning are good for 470-500RWHP with stock twin pumps at 55+lbs

 

I highly doubt the setup your working on is putting down these type of #'s

 

 

And injectors do have a aprox RWHP upper range, why wouldn't they... Yes it will be different for SC, NA or Turbos but each group should be pretty close

[Krambo]

Great thread!

 

I have been running my set-up with the radix for a couple of weeks and have no SOTP falling off at higher RPM's. I am shifting @ 6K 1-2 and 5900 2-3. I just hooked up my boost gauge and fuel pressure gauge. I see 65 and 8.5psi (just swapped the 3.3 for a 2.9). I took the truck to the track this weekend and did a 13 flat pass at FULL street weight (x-2000 speedstur, 3/4 tank of gas, baby seat and all) and the 3.3 pulley. I had 97mph trap speed. I am looking to go this weekend without the bed cover, spare and jack, less gas, no baby seats etc. and see if I can tuck well into the 12's with the 2.9" pulley. I want to give the truck a week to settle in from the new tune. I need to get this thing on a wideband!

[MN C5]

well, my findings are from what i can tell the 42lb hr injectors that the radix kit comes with are only just big enough for the stock pulley and good tuning. if you notice the track times from the radix trucks you'll find that the mph is always very low. with two SS trucks sitting side by side and doing tuning work we found that every time just before the shift point on either the truck would begin to creep up to lean. the amount and time is very little and no KR* is present due to this. we found this by installing a 2.8 pulley on an SS this weekend. it was certainly quicker and had we simply tuned it as most i suspect have by adding fuel and adjusting the timing tables to prevent KR*, we'd never have noticed the issue. running the smaller pulley certainly made the truck quicker and even the KR* wasn't rediculous. there was a small amount coming in over 5200 or so though. at this point we decided instead of just getting the timing tables where they needed to be and adding some fuel to the VE and PE tables we'd put the wide band on it. the truck ran a solid 11.8:1 afr by my settings all the way to around 4200 or so and began creeping lean. by around 5200 it was at the 14:1 area and at the shift point it had topped 15.x:1. trying every trick i could come up with to add fuel to the truck seemed to only help minorly and i could never keep it below 13:1 from around 5200 and up. it consistantly was over 14:1 by the shift. to see if it was just my settings we put the stock pulley back on. at this point the same tune resulted in an afr of around 9.2:1-11.3 all the way to around 5600-5700 where it would creap to around 13:1 very briefly and just before the shift so this was acceptable. i ended up retuning the truck back to the settings i had for the stock 3.3 pulley. the other truck sitting there had just had a radix put on it as well as a corsa exhaust. i had modified the airbox some also to get more air in. both trucks on the stock radix tune never showed lean because of the low timing tables and lower shift points. lower timing tables means unburned fuel and of course shows up as being rich. with a properly worked over timing table and wideband VE and PE table both trucks would go lean in the same spot which was about 50-100rpm just before the shift (lean being over 13:1 in this case). the 03' truck we had sitting there had a freshly installed walbro 255 in it and fresh fuel filter. we figured we'd test for a fuel volume issue by re-installing the auxillary pump. running both the walbro and auxillary pump did not change the issue. i know that when dcairns bought his radix it had a 3.1 pulley on it. the later models come with a 3.3. i believe this is more due to fuel requirements rather than the compression issue. it's been shown more than enough times that the smaller pulleys have no issue even on the stock radix tune driving around and having acceptable KR*. running the stock very rich radix tune will even allow for a smaller pulley and not show an issue because of the very weak timing tables and rich as hell program. with weak timing the KR* doesn't show to be an issue therefore even on a better tune such as a mail order tune one only watches for the KR* and never even bothers to check to see if the truck is lean or not. having driven the same truck with a 2.8 pulley and a 3.3 pulley, i'd say it would have shown gains in the quarter because the truck was so much quicker in the lower rpms and it crosses the traps before going lean in 3rd due to rpm becomes a problem (caused by the tall tires). i'd certainly like to see some more wideband numbers on this. the truck we put the 2.8 pulley on we ended up taking it back off until we can get bigger injectors for it an try again. i just didn't feel safe letting it go like that. of course our colder and more dense air up here in michigan only makes the problem a bit worse. with the only mods to this truck being my tunining work, a trailblazer converter, and a zippy kit, the truck went a 13.64@98mph. this is with a non-removable subwoofer box still in the truck and a heavy fiberglass toneau cover still on it and in 75 degree weather. taking away the 200 or more extra pounds would have netted some gain as will an exhaust, etc. i think that the reason the radix trucks are consistantly being held into the 13's even with going to the smaller pulleys and upping the boost considerably is these damn small injectors they come with. i feel a radix truck tuned with larger injectors and a smaller pulley with the average bolt on's would be dead into the 12's like the procharger trucks, etc with the same amount of boost (which comes in considerably earlier).

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Zippy its my humble opinion that the reason the traps are low and times aren't where they should be has more to do with tuning than the size of the injectors. Spin the crap out of the blower and keep your shift points below 6k and you'll go faster. A stock lighting tune has about 4 or 5 more degrees of timing than the tune supplied with the Radix. (This is from memory so I could be off a bit)

 

 

Would monitoring inj duty cycle show the problem?  How many pounds of boost did you see with the smaller pulley?  Most Radix guys are seeing around 8.5 max.

 

Also, aren't the Procharged trucks running more boost?  12lb on one of them.  They are using the same 42lb injectors.

 

60s would be way too big.

 

Not hard, but a PITA to change over to LS1 style pigtails.  42 is as big as they get for the truck pigtails.  Also need to raise the fuel rails.

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Ben I agree with you except that IMHO 60's aren't to big. They just require different tuning and would allow you to add timing by fattening up the fuel a bit.

 

 

i went 13.55 this weekend, trap of 96.35 mph (corsa, radix, 2.9, zippy kit & trail blazer converter - as well as a JL audio non-removable sub-box) vs. a 2001 camaro ss (headers, cut-out, gear, suspension & air lid - many of the major bolt ons...) which ran 13.52 @ 100.44 mph. I talked with Bryan from PCM4Less before the outting at the track and he had convinced me to switch plugs to Autolite 103's with a .035 gap (he said with the CHP truck they ran into "blowing out the spark" - oddly enuff on my camaro buildup both trick flow & holley reccommended Autolite plugs - prior to that i dont think i would have even put autolite in my lawnmower.... but in all honesty it seemed to have helped. Anyone know what 8.1L injectors flow? and whether or not their compatiable? (i havnt seen enuff 8.1's around the shop much)..... Zip, what do you think?

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I seem to recall BigTex saying that the 8.1 injectors are the ones that come with the Radix kit. I think they might have a 8.1 marine part # but are 42lb'ers.

 

 

I have two years and 10 sensors of experience on the wideband. Tuning both forced induction and n20 vehicles. Also lets note that fueling a ATI is much different then a Radix at the same PSI. Tuning and fueling a Radix is more like tuning and fueling a Turbo. It takes more at the same boost level. Ijector and volume issues will become present earlier. In one gear lets say 2nd the radix will eat more fuel at 8psi then a ATI going from 3000rpm to 6000. Just as a properly sized turbo would. 

Neither truck is blowing spark. I run TR6's gapped at .034 in both. The 03' also ahs MSD wires. What we are running into here is that we could make the truck go faster with a 2.8 pully like everyone else but it would not be as fast as it should be or "ideal". We would rather refuse to do the non ideal thing and make it work right. We could dump the timing and get it to have enough unburned fuel to keep it were we want at 11.8:1. Then why would you put that pully on. Great you can get it moving but then you end up with the weak Radix trap speed.

I think that a 2.75 pully should net 105+mph not 100-102 corrected. Look forward to us fueling one of these correctly with the proper injectors and pump. As i belive a single 342 will not fuel a pulley any smaller then 3.1" I have my doubts o nthe 3.3" with a good exhaust intake and a high but correct shift point. Time for dual intakes and 57's. We need to get one of these Radix trucks to trap the right speed.

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I agree with you, no spark blowing out and the traps. but not that 57lbs injectors are needed. Add fuel and add timing and she'll scoot

 

 

Interesting stuff, guys. Keep us posted as to your findings on correct fuel pump/injector size.

 

Supposedly CHP and Allen Nelson are also going to be testing for optimal pulley size and tuning on the SSS. Any benefit in sharing information with them?

 

It's always been a bit suspicious how the efficiency of the Radix seems to tap out between the 2.9 and 2.75 pulleys, in spite of the fact that at 6K engine RPM the blower still isn't maxed out. Maybe it's lack of fuel capacity, pure and simple.

 

Thanks Zippy for keeping us Radix guys in mind. 

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The Radix doesn't tap out between a 2.9 and 2.75 pulley. Its just the case of diminishing returns. The faster you spin the blower the less you'll gain moving the blower speed up the next time.

 

You can spin the Radix to 20k plus and it will still make boost, just any more than it did at 18k and the air is hotter.

 

 

 

Throw fuel at it with low timing and then turn the timing up till you get knock. Then play with the fuel again.

 

Don't spin your motor faster than you need to. Try the smallest pulley you can get and set your shift points lower... Tune for the blower not the fact that you can spin the your LS1 motor to 6000 plus. The Radix will produce loads of TQ but a lot of guys are setting the shift points up to blow past the useful range of the Radix.

[Hunter]

I was thinking of putting my Radix on a 402... Maybe I should hold off on that?

[hellbents10]

I would not reccomend a Radix for a 402. It will not push enough air to provide much of a gain over that motor.

[moregrip]

I would not reccomend a Radix for a 402. It will not push enough air to provide much of a gain over that motor.

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I hear rumors that it just might with that very same displacement.

[MN C5]

I would not reccomend a Radix for a 402. It will not push enough air to provide much of a gain over that motor.

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I had the Radix on a 427 and it made 7-8lbs of boost. It made even more boost with a broken valve spring (Some of you will know what I'm refering to..lol) As far as power goes it won't add as much as it would on a 347 for sure. But it will make tons of TQ and would be a worth while mod to a 402 hauling a heavy truck like the SS.

 

The Radix added about 60 peak flywheel HP to my 427. But it made that power early.. i.e. I think it hit 600 hp at 4400 and like 570lbs of TQ so low the dyno couldn't hold it down...

[whitt1]

I would not reccomend a Radix for a 402. It will not push enough air to provide much of a gain over that motor.

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I had the Radix on a 427 and it made 7-8lbs of boost. It made even more boost with a broken valve spring (Some of you will know what I'm refering to..lol) As far as power goes it won't add as much as it would on a 347 for sure. But it will make tons of TQ and would be a worth while mod to a 402 hauling a heavy truck like the SS.

 

The Radix added about 60 peak flywheel HP to my 427. But it made that power early.. i.e. I think it hit 600 hp at 4400 and like 570lbs of TQ so low the dyno couldn't hold it down...

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I'm running a 402 with a 228/234 .588/.598 cam and I'm only seeing 6lbs. of boost,I saw 618rwhp at 5900rpm,but was making 427rwhp by 4100rpm.I went with a bigger inline pump to remedy my fuel pressure loss.I had problems dynoing low rpms spinning my tires all the way through 2nd gear.

[moregrip]

I would not reccomend a Radix for a 402. It will not push enough air to provide much of a gain over that motor.

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I had the Radix on a 427 and it made 7-8lbs of boost. It made even more boost with a broken valve spring (Some of you will know what I'm refering to..lol) As far as power goes it won't add as much as it would on a 347 for sure. But it will make tons of TQ and would be a worth while mod to a 402 hauling a heavy truck like the SS.

 

The Radix added about 60 peak flywheel HP to my 427. But it made that power early.. i.e. I think it hit 600 hp at 4400 and like 570lbs of TQ so low the dyno couldn't hold it down...

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I'm running a 402 with a 228/234 .588/.598 cam and I'm only seeing 6lbs. of boost,I saw 618rwhp at 5900rpm,but was making 427rwhp by 4100rpm.I went with a bigger inline pump to remedy my fuel pressure loss.I had problems dynoing low rpms spinning my tires all the way through 2nd gear.

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well what do you know, the rumors are true

thats some serious power whitt! outstanding job!