how much noise?
 

This is probably a real newb question, but here goes anyway.

I have been reading about how the rotrex and whipple superchargers are much quieter than the roots blowers, I know turboes are silent (more or less), I've had a couple turbocharged cars.

I want to go with forced induction on my '01, I love the drivability of the stock torque curve so I'm leaning towards an MP62 based setup. However, I hate noise! That probably sounds contradictory from someone that owns a convertible, I actually find my stock car rather pleasant to drive, I don't like loud or harsh exhaust noise for example, just how loud are the roots type compressors?

Jim

Gee, hustler, thanks for the useful reply. Are you just naturally an a-hole or do you work hard at it?

Superchargers whine because of their gears. Turbos are quieter because they have no gears. Engines were developed to run timing belts instead of chains to reduce friction and weight efficiency losses and to reduce noise. Superchargers have tremendous friction and rotating mass losses compared to turbos. Supercharged cars always get worse mileage than stock, even when being driven normally. Superchargers are parasitic drag devices. Many here get far greater mileage than stock with their turbo cars.

A turbocharger sized properly for your desired powerband will make more power more quietly with less fuel than whatever supercharger you might be considering. You can make boost at 800rpm or 8,000rpm depending on what turbo you choose. Not demonstrating this understanding in your initial premise leads me to believe you don't fully grasp just how readily turbos are tailored to every need.

Just leave the car stock.

Thanks six shooter, i do understand turbo sizing and spool up time etc. I guess I should have added that I am interested in the supercharger route as much for the simplicity of installation as the power curve. I'm not to keen on running oil and coolant lines if I would be happy with the noise level of a supercharger. I haven't even heard a supercharged engine run, so it is a total unknown for me. I keep looking at the rotrex kits and wondering if it would be possible to fatten up the lower rpm range a little.

To be honest, i don't even know why i hesitate in going with a turbo, I loved the power output of my Volvo 740 turbo (intercooled and running 9psi boost and bigger exhaust). The power was seamless and it pulled hard from down low all the way to redline. I do notice the turbo lag in my truck (LBZ 6.6 Duramax), if you mash the throttle from a stand still it seems a little weak, then all of a sudden the turbo spools up and it takes off.

I think I have been getting to caught up in looking at the dyno sheets posted by the kit makers, it seems the turbo kits are lacking bottom end (but then again, they are probably using a midsize turbo for more top end ?) I like the the advertised torque curve of the JR MP62 kit. I also like the cold air box available for the JR kits. Although I am capable of doing some basic fabrication work to build one if I had to, I am getting lazy and like the idea of a true bolt on. I am only looking for around 200rwhp.

Is there a particular compressor you would suggest for quick spool up and a similar to the stock torque curve? According to dyno runs I had done on my car, I am getting 90 ft-lbs@3000, peaking at 98ft-lbs@4800 and dropping off to 80 ft-lbs@ 7000 (bone stock @ 3500 ft altitude). Obviously I am not going to get an identical torque curve, i don't expect that, but I would like close. I love the way my car pulls from about 3k to 7k in any gear for day to day driving.

Jim

Jim,

Speaking as a supercharged Miata owner, I think you should get a turbo. Anyone who tells you that installing a pre-fabbed supercharger is easier than a pre-fabbed turbo has never done one or the other.

9psi from a MP62 will be too loud for you and that's just the belt noise.

I selected a supercharger over turbo for one reason - AutoX performance.

You'll notice that there is no miatasupercharger.net. Ever wondered why?

Oh, and to answer your previous question. Some are born great, some have greatness thrust upon them - I think Hustler got both.

Why would the drive belt be any louder than say the ribbed and ridiculously long serpentine drive belt on ford V-8s?

its just loud.

you would be better off with a turbo. i just installed a MP45 kit on a friends car bout a month ago, it was a huge PITA. dont ever really want to install another.

Because superchargers suck a lot of power just to spin. To transmit that power requires a bunch of belt tension = noise. The nose pulley on the supercharger is very small causing a tight wrap radius = noise. The belt itself is a multi-vee = noise.

Personally I love the sound of a supercharger, and it's belt, at full chat.

For your expressed desires regarding torque curve I would say to look at a gt2554 size turbo. Compare dyno sheets from our dyno sheet posting thread with what you are making now. They have early spool characteristics. For these in a kit form, check out the BEGi-S kits. If you are moderately budget conscious I would look at the BEGi Shanghai kits. If you are willing to do a bit more studying, you can save more still and source more parts used, piece by piece, from our for sale threads.

If you decide you want more kick in exchange for a slightly higher powerband, the gt2560 is the next size up from the gt2554. You can also make adjustments to spool characteristics on a given turbo by swapping to different A/R housings. A turbo can be tailored like an Armani suit.

And yes, the folks at GM chose a laggy turbo for the Duramax engine. They didn't have to, but I'm sure they had their specific reasons/goals.

[QUOTE= and yes, the folks at GM chose a laggy turbo for the Duramax engine. They didn't have to, but I'm sure they had their specific reasons/goals.[/QUOTE]

I don't know if it has anything to do with the variable vane geometry, or if it's something else. Adding an AFE stage 2 intake and Bullydog programmer smoothed the transition, but it is still quite noticable.

My supercharger setup was very loud. That's why I now have a turbocharger under the hood.

I really enjoyed it, but you cannot beat the smoothness of a turbo :)

+1

you will never look back

(though in time, you may very well end up looking forward!!)

your all dumb, superchargers are teh awesome and sound > turboz

That's what my trans used to sound like...but i just replaced it so I no longer drive an RC car.

I LOOVE the scream of my supercharger!

OMFG. i'd kill myself if my car A. was that slow B. sounded like that C. both A and B.

Slow? That was half throttle. 3rd gear.

Holy crap those SC sound clip/videos were annoying.

Jeff's does look like/sound like a badass RC car.

need to drop the car off with artech for a weekend then it will be better... or worese. the guy does good work but a straight mid pipe and fm 2.25 is out of his control but for a track car power > sound.

I think of my SC as a catback exhaust, it makes some noise but in the end I am not that fast! I like the whine but wouldnt bat an eye if someone swapped me for an "okay" turbo setup.

your charger must suck, mine is good and fast.

It does suck. It is a Sebring m45 with BIPES and AFPR. On the otherhand Ive riden in a FFS setup with add-ons and a DIY turbo setup. I would still choose a turbo over a SC setup. That is unless I was soley into building a SSM car.

Here's mine (mp62)

http://www.youtube.com/watch?v=K5uTcHh3qWI (you can skip to about 1:15)

So basically it sounds like a stock Miata except when your hard on the gas, or did I miss something?

Thanks for posting that video RayvnX, I like the way your car sounds

Jim

Do you have a dyno sheet that shows those 250whp?

I picked up the car a little over a month ago. Previous owner says it was dyno tuned to 250rwhp. I'm a little skeptical so whenever I get this overheating issue fixed I'll find a dyno day to get a chart for everyone here.

10 psi on a SC = 250rwhp? I doubt it

Right, hence the skepticism. Others here have said it should be in the 200 rwhp range.

10psi on 99 w/ tdr kit is ~200rwhp.

standalone with proper tune will be 210-220.

Maybe he meant 250 crank? Although that seems to be a bit low: 250 x 0.8 = 200whp. No excessively low, but it all depends on tune (see Jeffs post).