If I may elaborate on the reason for a restrictive intercooler causing a very large power drop with a positive displacement supercharger...

With a positive displacement supercharger a fixed volume of air is pumped per engine revolution with a given throttle opening and rpm. In this sense, it is akin to a normally aspirated engine except with a wider range of cfm capabilities. This is why this sort of setup has similar drivebility and throttle response as a normally aspirated engine, except with a lot more power and torque of course. When an intercooler is put in the mix it can upset the power and driveability if it is not just the right size. Flow of the intercooler is very important since the supercharger cannot "make up" for lost flow downstream. The supercharger is at a fixed pulley ratio and cfm, so any restriction downstream will directly decrease cfm by the amount of restriction. Additionally the restriction will cause more issues because this restriction is also backpressure on the supercharger. We measure this backpressure with a boost gauge . That's right, more boost at a given blower drive ratio is not a good thing. This higher boost means that it takes a lot more hp to drive the supercharger which is directly related in the engine crankshaft hp. Also, higher boost means more heat and even less power. So a modest restriction with an undersized intercooler causes a cascading effect that decreases power substantially. Cfm goes down, drive hp goes up, and heat goes up. This means that in a supercharger application the intercooler sizing and priorities is different than for a turbo. For superchargers more cross sectional area and flow as opposed to lots of cooling area are priorities. Of course, we also need enough cooling area... but that is the key, just enough to keep throttled volume down and airflow up.

Having the wrong sized intercooler on a supercharger is very evident. On the dyno one will see it flatline at a given hp no matter what pulley size is used. This means if one tries to run a faster pulley size the hp peak will remain the same but the peak rpm will simply be lower. When the supercharger and intercooler are the right size the power should climb all the way to redline. Of course, it is possible to have too big of either. Too big of a supercharger will result in laggy low rpm performance while too big of an intercooler will result in sluggish throttle response. However, when it is sized just right the throttle response and low rpm power are very crisp.

Bill

 

Damn, how much are we loooking at for this kit? You guys are located in Greenville SC too?? Maybe I should make a little drive there..

 

Just give us a call before you come to make sure the car is in driving mode instead of torn down development mode.

 

not trying to step on your toes here. im glad there are companies out there trying to do new things.

your comment about knowing the intercooler is the fault by just looking at the dyno graph is not the correct procedure. there are many variables to why the setup is not making power till redline

IMO, and most hard core engineers will probably tell you the same thing. if you are in question about the intercooler. you need to do a couple things.

you can easily calculate the efficiency of the intercooler. by measuring air temp as well as boost pressure before the intercooler and after the intercooler, you can measure the exact pressure drop and be able to calculate the intercooler efficency. this will aid into correctly designing a good system and probably saving you time in the long run instead of just randomly choosing an intercooler.

Good luck.

 

Mase1, I'm pretty sure BRP are well aware of the steps and calculations required to selecting the correct intercoler; I'm quite sure they're not "just randomly choosing an intercooler." A small business like BRP would not be able to survive if its employees just took guesses on these things...

They've been in the Miata supercharging business for several years now, and have Miatas putting out over 300rwhp. If they can get a 1.8L Miata with this 'charger to over 300rwhp, I'm sure they'll have no trouble with the S2000. They're not spring chickens, man

 

so I have a question, most specifically for 3ngin33r and mase1, but also for a much broader range of members on here who all seem to sport the same attitudes....

what's with all the animosity???

 

good question......

I think for the most part people have said for so long that a roots charger won't work on the S 2000. And some folks are having a hard time realizing that somebody actually made it work.

 

There have been a lot of false starts with PD SCs but it is good to see someone actually getting somewhere.

I expect the animosity is from the once bitten thing, but also the usual sort of tyre kicking impatience. When you are developing a product there is so much interest and pressure and any minor set back (like the IC issue) is blown totally out of proportion. As soon as you actually release the product however a lot of the people who were so keen and supposedly had money waiting just seem to evaporate. Pretty sad really.

 

Not all of us...

 

Very curious to see how this kit performs...Keep us posted