Here's some dyno charts from other cars to give you an idea of power curves from this charger.

The first two are from an S2000, with the first one running 5psi and the second running 10psi, the other one is from a CRX with a K20 running 10psi. I consider those pretty flat ...

 

Perfect evidence - a linear power and torque curve, going up with RPM.

 

I think when most of us think flat we think "Torque hits low and stays steady throughout the revs." That is what the most of us would call very linear. Either way, it looks like a great addition.

 

Im lovin the work, cant wait to see it

 

Yay!!!

 

Just to correct myself, I previously mentioned that I'll be doing 70MM for the pulley, I actually meant to say 80MM.

 

Nice Very Interesting! Keep the updates coming!

 

I should have a pulley done before the end of next week hopefully.

 

So why did you decide to use serpentine pulleys instead of a Gilmer drive setup? Was it just for ease of sourcing replacement belts?

At least it should have a lot less rotating mass than the 7" Camden I was using. Horrible belt slippage no matter how tight it was.

 

interested in making a first gen alternator pulley duel sheave for two v belts in the stock size or slightly smaller?

 

Yes I'm using the serpentine belt for the ease of replacement and the lower cost. it won't be as easy to slip too because its gearing efficiency is so high (about 98%) vs a camdem which would be closer to 60% , that's a lot of wasted energy and would make it harder to spin putting more resistance to belt. I have seen setups run them with a 4 groove belt, but the 6 groove is more common and normally easier to source off the shelf, along with the added assurance that it just won't slip as easily with the extra contact on there. the belt will have over 180 degrees of contact to it also, with the addition of a spring loaded tensioner, I really don't see this belt slipping so easily.

 

the double groove pulleys are already available on re-speed website for the alternator.

I might be making a replacement 4 groove pulley to replace that and the water pump one though, also a better tensioner for the alternator instead of that groove bracket that always slips down.

 

Definitely in for results when done. Nice to see someone looking into more options.

 

so you know if those are stock diameter? i want to have my alternator run at normal speeds not under driven like it is now lights dim and what not at low rpm also i can hear my fuel pump surge when the turn signals are on.

 

sorry not trying to jack your thread pm me will you please? ill email billy too. thanks


Back the the Rotrex.... any more progress??

 

its a stock diameter pulley, no updates yet on the charger.

 

thanks!

 

Well I just finished designing the first pulley measuring 80mm a few minutes ago and will be sent out first thing in the morning for getting one machined. The first one that I'll be doing will most likely be just out of steel just to be a bit cheaper on it and to make sure that everything lines up properly first. If all goes well a second one out of aluminum will be made

 

It's more expensive to machine one out of aluminum than steel? 6061T6 is a good $20 cheaper for a 12" length of 3" rod on McMaster compared to the same piece in a low-carbon steel like 1018. That, and aluminum is so much easier to machine than steel. I'm curious what rationale the machine shop gave you for that pricing, it doesn't make sense to my student mind.

 

so what are you designing them with? on a cad program? or plastic or what? just curious i thought you were making them yourself

 

It might be cheaper out of Aluminum ... I actually haven't priced them out yet, I just assumed, and I did think of it easier to machine earlier on this morning. I posted that at 3am and didn't really think too much of what I was posting at the time.

I did the pulley just on AutoCad. My buddy will be turning the pulleys for me as he has the proper cutting tool and cut path for the ribbed portion. Other wise I could of done it myself and besides I'm so busy right now its actually kinda ridiculous ... Between running my car detailing business (people wanting their cars clean before storing), working at the restaurant a few nights a week, just doing random machining and welding repairs for people, and trying to find a big shop to purchase another business ontop of all that ... Ya, I'm a workaholic ... and no I can't find time for a girl in my life now lol.

 

got ya thats cool i want to know how that pulley works out for ya Sounds like you are busy geeze

 

The brackets will most likely be done in MDF wood first though for its cheap price then aluminum or steel ones will be done. the reason I say steel now is because I don't know if I can fit a piece of aluminum strong enough in there .... I think I only have about 1/4 " or so between the charger and belt

 

Well the pulley will be made out of aluminum, Ill have it on hand hopefully in a couple of days time. I had to well up some mufflers for my buddy in exchange for it ... then I have to finish his headers. He's building a full tube chassis car with the fiberglass body being the latest generation Honda civic, but in a widebody form, the power plant is a nsx engine with ITB custom ground cams .... quite the beast it should be! I have to do all the engine management wiring and tuning on it also .