Hi Guys just interested to know which is the best sort of supercharger to use for a VH45 for low end torque?

Twin screw supercharger will give you the most low end. Getting it to fit can be difficult tho.

Pictured is a VK45, tho both engines are very similar.

I read an article pointing out different forced induction methods with pros and cons. In my view the twin screw was by far the best. It did everything the old roots did but also ran hard all the way to redline and was way more efficient. The turbo had the highest peak torque and efficiency, however also the obvious drawbacks. Same as the vortech centrifugal, was the 2nd most efficient but buggar all lowdown boost.Can anyone put any links up that tell us more about the twinscrew? When I was looking I couldnt find any decent max recommended flow/hp figures. I wanted to find a twinscrew that is capable of around 800-1000hp, however none of the couple of twinscrews had such specs listed. Plus they only did kits for mainstream models. From memory they were lysolm (spelling) and another aussie crowd. The article I read was up around 700hp (again from memory) and was on a twin cam mustang v8 I think. All appologies about my lack of definite facts, however surely there must be more info out there if this design seems to be the way to go.

there is nothing like the pull of a 03-04 cobra with a whipple or kenne bell charger on it. i have been in one with a whipple supercharger, stock engine too. its good to work on fords

ultrapulse wrote:I read an article pointing out different forced induction methods with pros and cons. In my view the twin screw was by far the best. It did everything the old roots did but also ran hard all the way to redline and was way more efficient. The turbo had the highest peak torque and efficiency, however also the obvious drawbacks. Same as the vortech centrifugal, was the 2nd most efficient but buggar all lowdown boost.Can anyone put any links up that tell us more about the twinscrew? When I was looking I couldnt find any decent max recommended flow/hp figures. I wanted to find a twinscrew that is capable of around 800-1000hp, however none of the couple of twinscrews had such specs listed. Plus they only did kits for mainstream models. From memory they were lysolm (spelling) and another aussie crowd. The article I read was up around 700hp (again from memory) and was on a twin cam mustang v8 I think. All appologies about my lack of definite facts, however surely there must be more info out there if this design seems to be the way to go.

Lysholm makes a 2.4L supercharger. Kenne Bell makes a 2.8L and Whipple makes an enormous 5.0L units that will likely flow for 1300+HP.

killbill wrote:Hi Guys just interested to know which is the best sort of supercharger to use for a VH45 for low end torque?

I thought you had gone off a VH45? Good to see you have seen the light.

for a street application with low boost ie 6-7 lbs what are you guys thinking as the best twin screw eaton m90 or m112

G'day Darin just still weighing up all the options that are available to me,hey how did your turbo VH45 turn out ,did u achieve the objective?

definitely go with the m112 over the m90, you could get one from a cobra. with just 6-7 psi it would be fun. you could even get the blower ported for more fun. id say with a stock m112 at that boost at least 350 hp. tons of torque to boot.

I just finished wiring in the Autronic (SMC) ecu last night so now we will really see. I'm organising a comp for the 2 to4 Nov so will get to test it and the winch then. All things point to over 300rwkw with the 35's on! Which should be a bit of a handful in the mud.I have to cear the workshop in time for Bathurst at least, due to a grandstand being built for the race. The joys of having a pool table, dart board, fridge, TV and a stereo in the workshop. Maybe that has something to do with the time it has taken for the build as well!!!!!!!!!!!!!

Rewiring the engine has tidied things ALOT. the only factory wiring left is ignitor to coil and I'll do that later some time. I've use new plugs everywhere so now there is no connections between the engine plugs and the ecu plug. A must for our use!

hey guys bringing this back up

you think the eaton m90 is to small for the vh not really looking for more than 350 whp

i just picked this one up for free

I don't know but if it's from an xterra or frontier there is an overdrive pulley available for it that typically makes 8-9 psi on the V6.

That unit is quite a bit bigger than the unit that comes on the VG33ER. I think the S/C on the ER is an M62. I've got one sitting in my dorm room and it looks a fair amount different than the one pictured.

id say go with a m112 350hp would be easy and with low boost. one guy at work has two m112 off of some cobras and he might get rid of them for cheap if you want me to ask him. he was wanting to do a twin supercharged 5.4, but instead opted for a twin turbo 351. so the chargers are in good condition.

I mght just take you up on that offer, i was looking at the m112.

One thing that baffles me since i am a lifelong turbo guy. How do you regulate the boost on a supercharger i understand the pulley comes in to play here but how do you know what boost is what and how soon does the supercharger make the max boost.

marksport wrote:
Lysholm makes a 2.4L supercharger. Kenne Bell makes a 2.8L and Whipple makes an enormous 5.0L units that will likely flow for 1300+HP.

Been to their websites, and low and behold NONE of them list all the important specs like max impellor rpm, max approx hp, max boost, max flow (cfm etc). A couple of specs are available, however to try and custom fit one to an engine like mine is damn near impossible. I see Kenne Bell does a kit for a shelby 500 which is 800hp. This is close but still short of what I am tryingh to make. Why dont these guys want my money? Where is their serious info? I click on Technical and get an engineering drawing, or a larger throttle body.sheez thanks guys!

o answer the above Q, with an 'unknown' or tested engine you make a good educated guess of a pulley size and bolt one on. Your boost is basically controlled by the size of the drive pulley. The style of blower will determine what rpm the majority of boost is in. So its simple, test a few pulley sizes to get what you are after boostwise and youre done. That's the usual way that I am aware of.

Ok now that I feel better does anyone know of a twin screw which is good for a max of 950 odd hp? This is a bit above what i am aiming for but some in reserve. I know you (mark) said one is theoretically good for 1300hp but none of their info stated that. Otherwise its the Procharger D1 I have which is going on...

Actually there is a more methodical approach to solving this. I am at work so I don't have time to give you any hard and fast formulas but I will give you the algorithm

1. Many vendors (eaton/magnusson, vortech, etc..) will give you a map of CFM with respect to input RPM (usually this is pretty linear for a supercharger)

2. Input RPM is dependent on the engine rpm and the ratio of the input pulley and crank pully sizes.

3. How much "boost" or pressure above atmospheric you will see depends on the the engine's CFM at that RPM. This requires emprical testing but some estimation can be done.

For example we know our engines are 4.5 liters = 0.158916 cubic feet.And we know they are 4 stroke, V8's. So for each engine revolution (360 degrees) we have 4/8 cylinders being filled so divide that first number in half.

0.158916 cubic feet / 2 revolutions = 0.079458 ft^3 / rev

And we say we want to examine 6000 RPM = 6000 rev /min

So we estimate that our engine consumes 6000 * 0.079458 ft^3 /min = 476.74800 CFM NOTE: this is assuming 100% volumetric efficency which may not be right at that RPM. It's an estimate anyway.

So if you force in anymore air than ~477 CFM you are generating some boost. Now its a matter of determining the pressure you want at the manifold. Now lets say you wanted to have 10 PSI of boost (that is roughly 2/3 of an atmosphere so we need a ratio that is 1 and 2/3 = 4/3 more than the 477 CFM). In this example:

4 / 3 = x / 477 CFM --> x = 4 * 477 / 3 = 636 CFM.

So we find at what input RPM the supercharger makes 636 CFM by looking at the graph and size our pulles such that at 6000 engine RPM we get that input RPM. Now if you think this is difficult, I took a lot of shortcuts and I didn't even get into the ideal gas law. So if this is too complicated for you and it's just a loose estimation then I recommend you just pick a reasonable size and work from there since it will vary with intercooler and plumbing etc

Cheers for that. Looks awefully simple (for an approximate figure). The one thing I never thought of is trying to intercool a screw type with my present manifold and intercooler. Using a screw type will mean having to find room to sit it beside the engine (or somewhere not on top). However I will go to extremes to achieve the best allround outcome. I'll endeavour to 'talk' once I get closer to this part of the installation. (headers are nearly finished..yay)

I'm sure that last part was fudged up because of the fact that I didn't apply the ideal gas law so I didn't take temperature into the equation at all. However, up until the boost equations, it's pretty solid calculations.