Centrifugal Supercharger

[ou812]

I am currently working on my mechanical engineering senior design project, in which I am working on intercooler efficiency and effectiveness. In order to do this I am trying to get my hands on a supercharger set up for a 98 XJ. I’m looking for a Vortec, Paxton, Pro charger design that would be easy to install. I’ve done some searching and haven’t had much luck finding a company that makes them for a 4.0 liter. Vortec had an aftermarket company factorXengineering that made it for the 4.0L but it looks like there no longer around. Does anyone know what they did for this set up or does any have a set up like this that they are using? If it’s just Fabing up a mounting bracket and piping then that wont be a problem. What else would be needed to do this, if the boost was fairly low, maybe 6 psi? Would I need a new chip burned for the ecu? Any input would be greatly appreciated!! Thanks

[RichP]

There was a guy from sweden or norway that put a nice S/C in a YJ. Dont remember the brand but it was neat clean install.. He had pics posted oh, maybe a year ago or so...

[JJacobs]

*I haven't actually done this so take it with a grain of salt*

My understanding is you'd need at the very least some big injectors and an FMU. A wideband o2 box is almost a necessity for the safety of the engine. A stout fuel pump is in order too.

FMUs crank the fuel pressure relative to the boost level. If you get lucky the rate is perfectly proportional and you don't really have to tune much. There are some add-on controllers to mess with the fuel, and there are others that will auto-adjust based on the wideband rich/lean feedback.

I don't know how much of a project you want to make this, but have you seen the Megasquirt DIY EFI? 2-bar MAP and no FMU required.

[ou812]

I am somewhat familiar with the megasquirt system. That is going in another direction to the main scope of the project. So i didn’t want to get into that big of a project. I have 12 weeks to finish this project and need to convince the school to fund this project, unless I get donations.

For the project im looking into optimizing effectiveness and would have to base line a current intercooler set up and improve from there.

How does the intercooler work on the Kenne Bell SC? Sounds like just a finned pipe? Is there room for adding additional piping to the Kenne Bell and installing a typical intercooler like what is used mainly on a turbo car?

[Boostwerks.com]

What exactly are your plans for improving the intercooler design efficency? I'm not exactly sure what your objective is with this project. Are you taking a design that already exists and making it better, or designing something totally new? I specialize in building custom turbo setups, and have found that you can't get any more efficent than a nice water/air with ice in the water tank. It is EXTREEMLY hard to get better than 95% efficency reliably out of any intercooler.

Why exactly are you looking for a centerifugal SC anyways? you can intercool roots designs, although with your project I would look into to turboing it.

As a matter of fact, I will have a turbo kit coming out for the 4.0L here soon. Stay tuned... ;)

[ou812]

At first I looked into doing a turbo set up. But do to time I think it might be a hard task to complete in time. Also funding will be an issues here, though it sounds like I will be able to get companies to make donations. Its very soon in the design process and were looking for ways to improve on a current design and if we can come up with a new design. One of our tests would be just comparing a air to air vs. a water to air design. Also thoughts of using an Evaporation cooling type IC ( not sure how well it would work but its a thought) and slightly though about some type of peltier electric device. Any input on these? I find the peltier device interesting but very unsure about them and if this is even a task they could handle. If you’d like to donate a turbo set up id love to try it!! Id be interested in intercooling a roots design, it would be a whole lot easier if I can get a complete kit instead of piecing one together.

[Boostwerks.com]

Yeah, I just don't have the financial ability to donate a full kit for ya. It would be almost $3,000 for a complete setup.

so is your goal to make the most efficent IC, or just make one "better"? I'm still kinda confused what you guys are after. However, I can point ya in the right direction.

PWR and Garret make some of the most efficent IC cores out there.

Heres one of PWR's latest water/air IC's which allows you to put ice straight into the core. It's probubly the most efficent means of intercooling without using some type of compressed gas charge.

http://www.pwr-performance.com/images/icebox.jpg

In terms of good quality air-air intercoolers, look for ones that are a "bar-plate" design. the added surface area of the bar's allow it to be more efficent than a "tube-fin" design. Also, the higher the fin density is (inside and outside the core) the more efficent it will be. However, the higher the fin density is, the larger pressure drop it will have. Another thing to look for is what is called "turbulators." They are basically little slots within the fins that allows the air to pass between a fin in that same bar or tube further increasing it's effectiveness.

Bar/plate on the left, and tube/fin on the right:

http://www.are.com.au/feat/techtalk/tti01a.JPG

[POLAR_JEEP_04]

www.avengersuperchargers.com (http://www.avengersuperchargers.com)

www.hescosc.com (http://www.hescosc.com)

[philip_g]

out of curiousity why a centrfugal?
I run a procharger on my GTO and it would be worthless on the jeep for offroading.

[Beej]

out of curiousity why a centrfugal?
I run a procharger on my GTO and it would be worthless on the jeep for offroading. Street and performance forum...

[Dr. Dyno]

Centrifugals are relatively easy to install and take up little underhood space, but they don't start to make any performance difference until you hit 3000rpm, and then you've only got 2250rpm more before you hit the rev limiter.
If you build your engine to make most of its torque at low/medium rpm when naturally aspirated, adding a centrifugal will boost torque at higher rpm and make the torque curve wider and flatter.

[philip_g]

Street and performance forum...like mentioned you're going to make peak boost at 4500 RPM just before you hit the limiter. I suppose the advantage of a low redline is you can run a pretty large crank pulley and a tiny blower pulley over such a narrow range.
But really, who drags a jeep? Turbo is easier and cheaper.

[ou812]

In my case im just trying to do a project for school and thought a centrifugal S/C would be the easiest set up. Does anyone know what type of intercoolers are used with the current supercharger set ups? Are they able to be modified? From what I read on Kenne Bell's website is that the intercooler is more or less a finned pipe, is this true? or is it a typical intercooler?

[philip_g]

In my case im just trying to do a project for school and thought a centrifugal S/C would be the easiest set up. Does anyone know what type of intercoolers are used with the current supercharger set ups? Are they able to be modified? From what I read on Kenne Bell's website is that the intercooler is more or less a finned pipe, is this true? or is it a typical intercooler?my procharger uses a standard air to air.

[ou812]

How about the IC's on kenne bell, avenger or hesco superchargers?

[philip_g]

can't say for sure but assume the same unless they're + displacement.

[Dr. Dyno]

Turbo is easier and cheaper.

Agree about the turbo being the best form of forced induction for the 4.0 (and stroker) since you get a big boost in torque from as little as 2000rpm to the redline (depending on turbo size). Installation is relatively easy but since the turbo glows red under hard use, you'd be well advised to insulate it so adjacent items such as electrics, rubber hoses, plastics don't get cooked. The lack of underhood space in the XJ means that the turbo will probably need to be mounted high, so you'll either need to cut a hole in the hood and add a hood scoop, or substitute the stock hood with a cowl hood.

[philip_g]

Agree about the turbo being the best form of forced induction for the 4.0 (and stroker) since you get a big boost in torque from as little as 2000rpm to the redline (depending on turbo size). Installation is relatively easy but since the turbo glows red under hard use, you'd be well advised to insulate it so adjacent items such as electrics, rubber hoses, plastics don't get cooked. The lack of underhood space in the XJ means that the turbo will probably need to be mounted high, so you'll either need to cut a hole in the hood and add a hood scoop, or substitute the stock hood with a cowl hood.

actually what I had kicked around for a CHEAP CHEAP setup would be to buy a used TD04 out of a WRX, cut the down pipe fairly low, weld in an exhaust flange like the WRX up pipe, since the turbo fits that already, then reconnect to the exhaust with a short DP. Of course your intake plumbing would be longer, and you'd need some sort of scavenge pump to pump engine oil back up to the engine, but the STS systems set up in a similar fashion work pretty well.

[BoostedHULK]

there is no rule that says a centrifugal supercharger reaches positive manifold pressure at 3000 rpm. this depends on compressor size and pulley size, that's all. You can have one that spools at any rpm you want, literally.

[philip_g]

there is no rule that says a centrifugal supercharger reaches positive manifold pressure at 3000 rpm. this depends on compressor size and pulley size, that's all. You can have one that spools at any rpm you want, literally.

Yes, but the faster you spin the CSC down low the more you boost up top considering it's a linear spool, unless you run something like a restrictor plate or something similar to a wastegate setup to vent excess boost.

[BoostedHULK]

It is NOT linear.

[philip_g]

It is NOT linear.
My procharger begs to differ

http://www.miataturbo.net/philip/gtodyno.jpg

Please explain how a compressor tied directly to engine RPM is not linear.

[BoostedHULK]

Torque falls off after 4500. If what you're saying is true, you could keep adding rpm and boost and fuel and that engine would continue to make power. That's not true. There are a million factors that ALL change how an engine performs at what rpm range, how wide a range it makes power...there's nothing linear about it. Cam design, ignition, fuel delivery, air flow into the comb. chamb.

[BBeach]

Didnt anything ever happen with this project?

[Pro Stock John]

I run a Griffin air to air front mount in my 98 turbo Formula. I ran a similar unit when I was supercharged with a Vortech YSi. It's the more inferior tube and fine design. I was always told to keep the inlet air temps below 150F at WOT.

You could pulley a centrifrugal setup to hit more boost and just shift lower. Some LS1 guys running the Vortech G-Trim LS1 kits would swap from a 3.12 to a 2.75 or even smaller blower pulley and would short shift. But Dr. Dyno's comments about the rev limiter nicely points out that it's pointless to run any old blower setup, since a blower like that might also move your power peak up 500 rpms. (all generalizations from me BTW).

[BoostedHULK]

i know this is REALLY old, but just happen to be reading through some old crap, and as far as the amount of air flow, it isn't hard to vent excess air with a pop off type valve.