Procharger Supercharger

[-Nemesis-]

Gave it a decent workout today, this is the boost characteristics I discovered:

After it hits boost it jumps to about 4psi, then hangs there, there's no linear rise, untill just before redline where it has a little spike to nearly 6psi, but i'm talking from 5700rpm at the earliest.

Not sure why it spikes there, but for the most part i'm seeing 4psi, so I guess the 3" intake is too restrictive. If I could get it to hit a 7psi ceiling and stay there the way it's doing it with 4psi i'd be laughing.

 

[spf_lexus]

Are you using an intercooler Nem? IC sucks up 1-2psi usually. If you could cram one in you can keep 6psi but have it producing numbers an 8psi system would offer. I feel ya, i wasn't too stoked on 5psi... I wouldn't mind 8psi maybe 9 but now im dreaming lol

 

[JustenGT8]

You guys know how your centrifugal SCs produce boost right? It's solely in response to compressor speed which for you guys is fixed by revs....ANY no linear boost response is due to problems with your setup ie you can have less boost and any point to give a flat boost response but you can't have more.

So Nemesis, after 4 psi (and maybe before) there is something about your setup that is preventing a linear increase in boost. Yes i would be looking to improve that but don't expect to suddenly have 6psi instead of 4psi and same boost response curve. If you resolve the issue you will just get a steady increase from 4 to whatever max boost the pulley gearing will give.

With centrifugal SC max boost is always at max revs in an optimised system.

 

[-Nemesis-]

Yep, know exactly how they work

I did plenty of reading before install and apparently you can set them up with a wastegate to control maximum boost, and incidently an intake restrictor can do the same thing (if it's not too small like mine atm)

You use a smaller than ideal pulley like I have, the idea being it hits your desired boost level earlier in the rev range, then whatever limiting device you use maintains your max ceiling. I think the only risk is overspinning the supercharger but I won't have any risk there, I assume my 3.4" pulley is only good for 10psi anyway

 

[stevechumo]

It's not the 3" intake pipe size that restricts the boost . The smaller the pipe, the faster the air will travel from the supercharger to the TB. Too small will restrict the flow, but 3" is plenty enough. You can run 20 psi with 3" intake pipe with no problem, maybe more. You may check the pipe angles; tigh cut angle will cause the problem. And check the vacuum hoses that might leak. When you floor the gas, did you feel the power increasing in linear? Don't pay attention to the gauge because the gauge might be faulty.

 

[-Nemesis-]

Sorry not the intake to the engine, the intake to the supercharger itself (i'm running a snorkel back into the engine bay as it's too tight for a filter in front of blower.)

Restricting the air flow the right amount will reduce the max CFM entering the supercharger. It's an interesting read, i'll see if I can find the link. If you get it right you end up with a more efficient system than using a wastegate because the blower isn't trying to compress as much air to achieve the same psi result down stream.

 

[JustenGT8]

The problem with running the SC harder to get more boost earlier and then bleeding off to maintain a constant peak is you run the risk of pushing the Compressor out of it's peak efficiency range. So for the same boost you get more heat and less power.

I say never try to make a system something it's not

 

[-Nemesis-]

Yep, precisely why i'm trialling the restrictor method.

Here's the discussion, it gets interesting from post 18, the guy knows his stuff

http://forums.corvetteforum.com/showthread.php?t=1982378

Oh and btw spf; I am running a front mount intercooler. Will get a build thread after this weekend I promise!

 

[JustenGT8]

Just run the boost mate, a stock UZ will take plenty if your ECU is good enough

 

[-Nemesis-]

I'm paranoid about my old head gaskets though

ECU wise it's stock Toyota, with a catch. The LPG has it's own ECU that feeds off the info the Toy ECU gathers, Neil used heavy duty injectors for the lpg but not too sure how far they can be pushed yet. Won't go too nuts till I get it on his dyno next Friday.

But yeah, started building a 90mm smooth wall snorkel (filter to charger) today, will be interesting to see the difference. The flexi 3" pipe I was using fits inside the 90mm stuff lol (p1sc intake is 3.75")

 

[spf_lexus]

Justin

If you think about it, both of us are not going any higher than 10psi max. Given that the P1sc supports 600+hp and by utilizing a 14psi pulley your ceiling wont get anywhere near its max operating speeds anyway. meanwhile we get our cake and eat it too by benefiting from the quick response a small linear pulley will offer but w/o the brutal top end. the idea is to sort of speak, "bridge" a turbo with a roots blower. Now if we had a 2 staged boost controller you would really see what I mean.


Downside is the price over the already finished setup and R & D.

 

[-Nemesis-]

So I ran it here to work with a 90mm intake feeding the charger and it still seemed to get a non linear boost ceiling of around 4psi, I guess i'm losing boost elsewhere...

 

[spf_lexus]

Just bolted mine back on yesterday. waiting for the weekend for the final touches and tune. Hey Nem i totally forgot you have LPG, any chance it's messing with the burn? well, using FI and all.

 

[-Nemesis-]

I don't think so, LPG likes boost...

I had an old Uni Filter element from the V6 which I cable tied over the end of the 90mm pipe and tonight coming home it wouldn't crack 4 psi. So I pulled over and took the filter off, then took off up the road and peaked at 6 or 7psi, so it must have still been restricting it.

Just now in the garage I went over every hose clamp after the supercharger and a few didn't seem too tight so I could have been losing little bits there. Tomorrow will tell the next stage of the journey.... (2am now)

The only things that might cause a little pressure drop that I can think of are: intercooler (which you have), 2 hump hoses for stress relief in the plumbing (these apparently can drop pressure a tad) and from my charger outlet I have one 90 degree bend straight into another 90, so it turns back on itself, though it's two elbows and not THAT tight a turn (compared to a 135 degree elbow +45 etc....) Remember I have a 3.40" pulley.

 

[spf_lexus]

Sounds like your real close. Being humble customizers... doing it all ourselves always leaves bugs to sort out. I noticed mine was loosing booost but ot was popped couplings. I would rev her up and you could visibly see 2 silicone straights "pulsating" back and worth with air rushing out at high rpm, I even had my MAF pop out of it's sleeve!! I thought they were tight but I maxed them out and had a better overall curve. I would try running her w/o ANY filter. All I have is fine metal screen material w/ T-bolt. Doing that would let ya know if your element is your problem, higher boost w/o? there ya go lol. I don't worry about objects/dirt too much because I have so many things obstructing air flow. A/C cond, radiator, IC, fans and a headlight all blocking direct path. I figured if you cant beat em' join em. Just figured no way to route a pipe out fo the hot engine bay, might as well benefit somewhere and betetr flow was all i had. Give it a try, IMO i would opt for the snorkel idea for your app. Hey you didn't by chance use the "krinkled" flexy hose for your before pipe? if so I hear they create a lot of turbulence for blowers.

 

[-Nemesis-]

I did use the flexi hose on the first attempt. The problem with filtration is most of the damage is caused by particles you can't see, too small to see but big enough to hurt. Mine will see plenty of dirt action so i need to sort out a nice sealed unit eventually.

 

[spf_lexus]

I would have a hard time running w/o filter on a 4-runner lol. I used to have a long travel Tacoma way back when with a 1 foot wider track width in front w/ 16'' travel, drove her w/o my filter and dirtied up the MAF in 20 min. Ocatillo wells gets pretty dusty out in CA.

As soon as i'm out of class tomorrow i'm firing her up w/ the procharger. 1st time it will be run since the re-build. All is needed is to attach a couple vacuum lines for FMU, swap belts and my trusty screw driver for tuning. I get kinda nervous before startup.... mind starts considering "what if".

My charger has |__________| room for a filter, not much option lol, if i went 90 degree i would be restricting the flow. Only answer I can think of is the filter material for 2-strokes. maybe cut out a circle and slide under the T-bolt between the screen.

 

[-Nemesis-]

lol yeah I was so nervous before the first turn key!

I would say I have less room than you lol, only difference is mine sits beside the radiator so i've cut a hole and gone out through the front!

 

[spf_lexus]

Well after a few months of neglecting my intake here was my final solution. I had to cut out the backside of my headlight and trimmed the rear sheetemtal housing to accommodate this massive 4'' system. I don't think there was a single square inch wasted! The LS has about 4-6'' less frontal room compared to the SC.

 

[Lextreme II]

Nice...Let me know where u got those parts. Need them soon for my car.