: Roots style S/C for the northstar. Anytakers?



1badcaddy
09-10-07, 08:26 PM
Soo what if a custom hood with a bump in it would be required. This would make for a mean STS. Imagine how much power you could make if you could get the tranny to handle it. I wonder how much they cost? Those of us with the 93-95 should be able to make it work since Westers still custom programs chips for us. Hell I'd cut a hole through my ghost flamed hood to let that polished blower breath. The car is only used for weekends anyways.
http://www.mechtech-ms.com/images/gallery/supercharger1.jpg
http://www.mechtech-ms.com/northstarSupercharger.php

eldorado1
09-10-07, 09:05 PM
Someone was selling a complete kit (might have been them) for $6k on ebay... supercharger, manifold and injectors.

1badcaddy
09-10-07, 10:22 PM
That sounds about right. Especially if it is highly polished like that with billet fuel rails. I wonder what else would be needed? It should still work with all the factory accessories. If you didn't have a HG problem yet you will after this install.

Raze
09-10-07, 11:24 PM
easier to setup a centrifugal supercharger with a real intercooler, no need for custom intake or rails, no hood bump, just need a custom bracket and new belt arangement, cost would be in the 6k ish range w/o tune...

1badcaddy
09-10-07, 11:49 PM
But has anybody done a custom Centri setup on the cramped Northstar yet? I imagine it would have to be a reverse rotation Vortech and it will be in the place of the battery tray and be a bear to install. That is the same way SHO's and Maximas do it. Anyways the Northstar is lacking in lowend torque and the centri's only provide mid-high end hp due to spool up time. The one I linked above will fix that problem real quick Get these pigs off the line allot quicker and into the upper RPMs where they want to be. Oh and where in the heck is the Water pump in that picture above? Would it still be in stock location and the belt wrap back around it?

Raze
09-11-07, 11:43 AM
It would take some fitting, but as long as you rotated the outlet housing downward there'd be a minimial amount of cutting/pounding to fit.

As for the low end torque, you really don't need anymore on these cars, especially if you have the shorter 3.73 gears in the ETC, STS, or DTS which as is comes close to breaking the tires loose from a standstill on good tires/dry pavement. More low end power is going to make you spend more time/money trying to keep the nose down so the tires don't break loose, plus the additional cost of a custom hood for a roots/screw style blower and the inability to really cool the air charge (aftercoolers would just make the thing stick up that much more and cost a bunch more), another setup would be preferable.

When last I spoke with Mark about his Turbo'd 99 STS he said 1st gear was useless and 2nd only mildly useful as he'd still spin starting in second when his boost would come in around 2-3k or so. His setup was also a nightmare to plumb, and very expensive.

I know both a turbo or roots/screw would be preferable from a power standpoint to a CSC but I think it solves 2 major problems better than either of the other alternatives. First is integration, besides battery relocation and custom bracket/belt, plumbing a FMIC would be easy and you could use stock intake, TB, fuel rails. Second, traction, our FWD cars loose traction during burnouts cause the back suspension is squishy and we can't put bigger tires on unless you don't plan on turning. A roots/screw would get you out of the hole faster but not if the tires are spinning the whole way down, same goes for the turbo, the CSC comes in later and can be easily tailored with an electronic/programmable wastegate to maximize traction as well as power.

this is of course just my .02

1badcaddy
09-11-07, 03:22 PM
I agree with you but I just don't like Centri supachachas that much. They require rebuilds, are heavy, use engine oil(tapped), etc.. I am a turbo guy myself but after seeing Marks turbo'd 99' I said screw that. Tha was a tight fit and plumbing nightmare. I guess if somebody stepped up and made the backets and tensioners pullies needed to mount and keep from belt slip then people could buy new or used headunits and piece toghter intercooler and cold side pipe kits.

eldorado1
09-11-07, 03:25 PM
uhh... heh.... the supercharger and intake on the 4.4L N* weighs 70lbs. It requires an adapter for an engine hoist to remove it.

Also, ones like the Paxton have self contained oil reservoirs and don't need pressurized engine oil.

1badcaddy
09-11-07, 03:37 PM
I know but we were talking about Vortech. Sorry I forgot to specify. BTW that 4.4L's Supachacha weighs a ton! Never heard of them weighing that much before. Usually it's less then or equal to that of the Centri's due to the swapping of the inake manifold for the roots intake and unit. Then the Centri's have the 20+lb head unit and all the oil fttings/lines, heavy steel bracket, extra tensioners(if needed) charge pipes, intercooler etc...

1badcaddy
09-11-07, 03:41 PM
Oh and battery relocation bracket/Box, extra large gauge cables to move the battery away from the original spot. I guess forced induction isn't really feasable on these Northstar engines.

Raze
09-11-07, 10:27 PM
Actually I was thinking more along the lines of a Paxton due to the self-oiling design but I like Vortech and ProCharger just as well, an oil line isn't that big a deal. I've heard most people get more miles out of Vortech but I've seen Paxtons get to 20k miles before needing a rebuild which isn't too shabby.

GizmoQ
06-14-09, 05:57 PM
Well I guess, I'm a poser then. I did it more to motivate me into getting it done and done right. The suspension is easy, I modded my 95 with new suspension parts and dropped and tighten up the handling. So I already know what to do there. Then I ran into the first roadblock -Big Brakes. Brembo said they could do 13.8" 4 piston front 12.?? 2 piston rear for $8500. I was floored! Next AJ stopped development on 96-99 NorthStars to do NX for Codewise and then he got all involved in his move so I'm leaving him alone until he gets settled in. For the 0-60 under 5 seconds, as soon as I can get my hands on a decent used VorTech supercharger, I can begin designing the piping and mounts to run it off the waterpump pulley, then I'll get AJ to tune.
Lastly, enhanced styling cues is pretty much done except after facing the above issues I stopped development on my rear wing, but that too is an easy add.

Don't forget that the water pump drive pulley is attached to the intake cam, so it rotates at half engine rpm.........

............... which brings up a simple question: How long will that single roller front cam chain last if tasked to drive a 2.5 or 3 to 1 stepup blower pulley ?


I know this is probably the wrong post to add this to, but Sub and I need to discuss this further. And if possible ETC and AJ jump in here and add your expertise.

Since I'm only trying to generate 3-6 pounds of boost, a smaller pulley will allow me to spool up just as fast or faster than someone spooling 12-30 PSI. A smaller pulley/Vortech would also be less stress on the cam chain. Problem is Vortech's power graphs are almost impossible to interpret without a degree in aeronautical engineering - which I HAVE! They're supposed to get back to me to tell me which custom combo will best meet my needs, but haven't heard back from them. Their S1V looks like a best fit to me, but I'll only be using 15-20% of its capability at my max PSI.

Vortech swears 4-6PSI will work with stock components and electronics and they charge a premium for custom configurations. Let's think about this! I want a slow screw, low boost, and smaller body. None of which they will supply. They want to sell me one off the shelf and tell me to get XYZ size pulley to meet my needs - AND THEN THEY WANT TO CHARGE ME A PREMIUM. I don't think so!

Submariner409
06-14-09, 06:30 PM
A Roots blower does not "spool up" (a turbocharger term) because it always runs at a fixed ratio of engine rpm. While a Roots may supply some boost at low engine load and rpm depending on the pulley ratio, a turbocharger depends solely on exhaust gas heat and volume to spool up - as in blowing on the pinwheel, therefore the term "turbo lag". A turbo really needs your foot in the floor and high exhaust gas flow to produce more than absolute minimal boost. At any condition other than power application (throttle opening) a turbo loafs along producing NO boost. As a matter of fact, a turbo is a restriction in the intake and exhaust systems unless it is driven to boost volumes. In a like vein, a Roots blower is a net power drain (something has to turn it, like an A/C compressor that gets harder to turn the faster the engine turns........) until the power derived from boost overcomes the drive power necessary to spin the blower........TANSTAAFL.

We used to do a few turbo tricks back in the Dark Ages, (60's) one of which was to wrap the entire pre-turbo exhaust piping in glass and asbestos insulation to keep as much heat in the system as possible. Man, does galvanized exhaust pipe rot out an an incredible rate under those conditions.......and for Roots blowers, before the advent of serpentine belts, it was common to see 2 or 3 sheave belt pulleys driving a 4-71 or 6-71 blower. The smaller the blower pulley, the faster it turns, and therefore requires more power to turn, placing undue stress on the drive system.

GizmoQ
06-14-09, 06:45 PM
A Roots blower does not "spool up" (a turbocharger term) because it always runs at a fixed ratio of engine rpm. While a Roots may supply some boost at low engine load and rpm depending on the pulley ratio, a turbocharger depends solely on exhaust gas heat and volume to spool up - as in blowing on the pinwheel, therefore the term "turbo lag". A turbo really needs your foot in the floor and high exhaust gas flow to produce more than absolute minimal boost. At any condition other than power application (throttle opening) a turbo loafs along producing NO boost. As a matter of fact, a turbo is a restriction in the intake and exhaust systems unless it is driven to boost volumes. In a like vein, a Roots blower is a net power drain (something has to turn it, like an A/C compressor that gets harder to turn the faster the engine turns........) until the power derived from boost overcomes the drive power necessary to spin the blower........TANSTAAFL.
Yeah, I knew this wasn't the most appropriate place to continue this discussion. Vortech superchargers aren't roots or turbos - somewhere in between. Thats why they're called centrifugal superchargers, i.e., spool like a turbo but driven by a belt.


We used to do a few turbo tricks back in the Dark Ages, (60's) one of which was to wrap the entire pre-turbo exhaust piping in glass and asbestos insulation to keep as much heat in the system as possible. Man, does galvanized exhaust pipe rot out an an incredible rate under those conditions.......and for Roots blowers, before the advent of serpentine belts, it was common to see 2 or 3 sheave belt pulleys driving a 4-71 or 6-71 blower.

I remember doing this, too.

Submariner409
06-14-09, 07:10 PM
Not a problem....the old Paxtons had to spin at some incredible speeds to generate boost....... turbos are in fact centrifugal blowers, but exhaust driven, whereas a Vortech is belt driven, so it needs darn fast speeds to produce boost, and the larger the engine displacement, the faster it needs to spin..........regardless, you'll have to admit that you need to spin this puppy pretty darn fast, and a cam drive will NOT do it.

A 6" crank pulley driving a 3" alternator spins the alternator at 2:1 - 1,000 engine rpm = 2,000 alternator rpm. A 6" cam pulley drives the same alternator at half speed because the cam runs at half engine speed, so you would need a 12" cam pulley to equal crank speed in this case. It will not work to drive a centrifugal blower.

GizmoQ
06-14-09, 11:10 PM
Not a problem....the old Paxtons had to spin at some incredible speeds to generate boost....... turbos are in fact centrifugal blowers, but exhaust driven, whereas a Vortech is belt driven, so it needs darn fast speeds to produce boost, and the larger the engine displacement, the faster it needs to spin..........regardless, you'll have to admit that you need to spin this puppy pretty darn fast, and a cam drive will NOT do it.

A 6" crank pulley driving a 3" alternator spins the alternator at 2:1 - 1,000 engine rpm = 2,000 alternator rpm. A 6" cam pulley drives the same alternator at half speed because the cam runs at half engine speed, so you would need a 12" cam pulley to equal crank speed in this case. It will not work to drive a centrifugal blower.

I'll admit I don't know the math, but (given everything else is linear) if the cam pulley turns at half engine RPM driving a VorTech setup at 12 PSI, don't I get 6 pounds of boost. I am not naive enough to accept the linear assumption, but looking at the boost charts from Vortech, I ought to be able to get something to work.

dkozloski
06-15-09, 12:01 AM
Latham axial flow superchargers constructed like the compressor section on a gas turbine engine are more efficient and out perorm anything else I ever saw.

97EldoCoupe
06-15-09, 12:28 AM
What we need is a shop that will convert these cars to a RWD car, aluminum tube chassis, Northstar installed longitudinally, with a true dual exhaust setup & headers. Then throw that blower on top.

If I wasn't so dang busy doing HG replacements I'd do this to my '97 Eldo. The problem is the chassis controls- the whole stability system & traction control systems would have to be reprogrammed. A Catera rear diff/axle setup would be ideal, although I'm unsure of their final drive ratios. Maybe even a IRS setup from a late model GM F-body.

This setup would solve the traction problems, and make the car a whole hell of a lot more fun to drive....

Submariner409
06-15-09, 08:46 AM
You need to talk to Vortech and come up with their info on what blower rpm even begins to generate boost for a running engine. The 12# setting is immaterial in this instance, and is dependent on engine displacement, rpm, and blower rpm.

Because the cams are driven at half engine speed, the size of the necessary step-up pulleys to get the blower spun up to boost speeds would be insanely large: IF the target engine uses a 6" crank pulley and a 2" accessory pulley, the accessory is driven at 3:1 - at 2,000 engine rpm the accessory is driven to 6,000 rpm. If cam pulleys were used, the speeds are cut by half and the drive (cam) pulley needs to double in size, in this case to 12", to make the same 6,000 rpm ! It won't work because a centrifugal blower has to spin at incredible speeds to produce boost - a turbo operates at way over 10,000 rpm.

Pulley sizing and the ratios are what allows the crankshaft speed to be changed, by pulley sizes, in order to drive different accessories at different speeds with the same engine rpm. The alternator, power steering, a/c compressor, and water pump all spin at different speeds compared to the engine rpm. The alternator spins at almost twice engine speed, while the p/s pump spins slower than engine speed. When your car hits a WOT shift at 6,300 rpm, the poor alternator is spinning over 10,000 rpm.

codewize
06-15-09, 09:24 AM
Well 97EldoCoupe, if you don't have HG work now, you will soon.

BTW, how does the PCM handle all this?