Electric Supercharger Install + Testing + Q&A

[Wild Weasel]

There's some discussion earlier about the restriction caused by the compressor when it's inactive. The bottom line is that it's irrelevant. It's not enough to create an appreciable change in throttle response, and so long as it's available when you get to 100% throttle, there's no power loss. The only time this would come into play would be if you ran the battery down and didn't have it available. I'd have said you never need to worry about this because I was utterly unable to get to this condition despite my actively trying to, but now I'll qualify that statement by saying that you'll never have to worry about this unless you have access to a speed-limit-free Autobahn.

[Crazy2287]

As long as the flow rate did not exceed the compressors CFM ability i would expect series setups to factor boost levels. In this instance it won't work once the vehicles is ingesting somewhat less than the cfm limit of a single compressor.
For Parallel, Wouldn't the loading cause the compressors to self regulate? I wouldn't expect an increase in PR at zero CFM, but up to double the flow you would see a higher rpm/larger capacity car supported.
At any rate, this is how a standard turbo works, was interested to see these systems operating under similar characteristics. Don't see why not, the limitation is the speed of the compressor wheel.

?

How about tests with water injection into the mouth of the compressor? Any time air is compressed it increases heat, in this setup it would not warrant an intercooler but water injection is easy enough to implement.

Also, is there a plot for pressure drop across the compressor wheel when inactive, at X-CFM flow?

[Robftss]

*subscribing*
Sorry if its already been mentioned. I skimmed through pretty quick so i might have missed.
Have you done tests with 2 units in series and parallel and they affect?
If a singe supports 2 liter engine then 2 in parallel should support a percentage close to double the cfm?

Anyway, Missed this thread, shall now be watching with interest!

Series, aka sequential, PR x PR. ~Doubles boost, 1st compressor sees atmos, 2nd sees elevated atmos, both work in there operation range. See Robftss (you tube).

Parallel, each compressor needs to pressurize its own run to its own cylinders, ie 350Z (2 intakes). or, very tricky, a pressure balancer valve to keep flow from reversing through one or the other compressors.


Ultimately, bigger everything will create more CFM's. 250HP is the present max, but more to come!!

Rob

[Wild Weasel]

*subscribing*
Sorry if its already been mentioned. I skimmed through pretty quick so i might have missed.
Have you done tests with 2 units in series and parallel and they affect?
If a singe supports 2 liter engine then 2 in parallel should support a percentage close to double the cfm?

Anyway, Missed this thread, shall now be watching with interest!

Rob will have to answer that question definitively, but I don't think that's how they work. It's my impression that the blower will only push a certain amount of CFM through itself, so once that first one is doing that, the 2nd one will basically be spinning freely but not push any more air. It'll just cause undue stress on the motor due to it spinning faster with little to no load.

Essentially, this is what happened with the small one when used in series with my M45. At the top of the RPM band, it just wasn't keeping up and became a restriction. I have no reason to believe the same wouldn't be true if I put it behind the first blower (with it's own batteries) instead of behind the M45.

The real solution to needing higher boost or feeding a larger engine is most likely to go with a 36 or 48 volt version.

I actually broke down and registered on the FT86 forum, but still can't post because I need to get home to get the confirmation email.

[Crazy2287]

*subscribing*
Sorry if its already been mentioned. I skimmed through pretty quick so i might have missed.
Have you done tests with 2 units in series and parallel and they affect?
If a singe supports 2 liter engine then 2 in parallel should support a percentage close to double the cfm?

Anyway, Missed this thread, shall now be watching with interest!

[Wild Weasel]

Hey guys... I know I never got to do dyno runs with mine... but the FR-S guy just did some and they're hella impressive! Here's a link directly to page 9 where he posts them...

http://www.ft86club.com/forums/showthread.php?t=39719&page=9

Reading the whole thread is good fun though. It's got everything! The initial speculation... some doubters... a proper flame war in the middle... people coming in half-way through mocking the whole thing without having actually read anything... and then finally the dyno numbers pretty much blowing everyone's expectations out of the water.

[Wild Weasel]

wow, thats a long read, but it looks promising...I do have a question though... will this work on larger displacement/hp engines in the future? Like an n/a LT1 or LS engine? As far as i read, its good up to 250 hp engines?

The current design won't work because it simply won't push through enough air to boost an engine that size. I know Rob's been working on versions using 36 or 48 volts though, which I'd expect would be able to handle it or provide way more boost to smaller engines. So... while this particular version won't do it, that's not to say there won't be such a thing in the future sometime.

[Mongoose Hunter]

wow, thats a long read, but it looks promising...I do have a question though... will this work on larger displacement/hp engines in the future? Like an n/a LT1 or LS engine? As far as i read, its good up to 250 hp engines?
Also, on a slightly unrelated topic, has anyone here seen the Motor Trend Roadkill episode with the leaf blower superchargers?

http://www.youtube.com/watch?v=U81_0waqEWA

[AlexanderB]

Lol, you wish you lived near Germany (no speed limit on the autobahn) I've done WOT runs in excess of half an hour.

[Wild Weasel]

Its like you said though ( i think it was you) you cant do a minutes worth of WOT in one go on the road. You just run out of space. The road aint no race track. This just shows how usefull this sort of thing could be on a road car. You wouldnt see it in motorsport but deffo small displacement cars.

It will definitely be useful on the drag strip for casual racers.

One interesting thing i did notice on some of the dyno graphs is how the smaller blower seems to generate more boost to start with but tails off quicker (obviously). Better get a twin electric supercharger setup in the pipeline :lol: :lol: :lol:

Yeah. Remember that both blowers are using the same power source. It's not that the bigger one is more powerful. It's just more efficient at different places, if that makes sense.

The most WOT i ever get on my way to work is maybe a couple of second and third gear pulls...thats what...5 seconds? maybe 10

Exactly. That's why I had a hell of a time trying to run it down just to see how long it would take. I resorted to trying to hold my brake while mashing the throttle in 5th gear and just holding it there... which was obviously idiotic.

[Vetrox]

The most WOT i ever get on my way to work is maybe a couple of second and third gear pulls...thats what...5 seconds? maybe 10

[Wild Weasel]

Looking at the last comment there made me chuckle.

Some info i got from the site: I believe this kit is in the $1300 range. As well it's the charge that doesn't last, with an 8:1 ratio for charge:boost. So if you continuously boost for 1 minute, it will take roughly 8 to recharge that amount.

I think the comment was meant to be negative... but I don't think he realizes how impossible it is to be at WOT for a minute.

[Vetrox]

It's fun to see him having the same challenge I had in trying to run down the battery.

Its like you said though ( i think it was you) you cant do a minutes worth of WOT in one go on the road. You just run out of space. The road aint no race track. This just shows how usefull this sort of thing could be on a road car. You wouldnt see it in motorsport but deffo small displacement cars.

One interesting thing i did notice on some of the dyno graphs is how the smaller blower seems to generate more boost to start with but tails off quicker (obviously). Better get a twin electric supercharger setup in the pipeline :lol: :lol: :lol:

[Wild Weasel]

I've been following that thread closely on the FT86 forum. Sometimes trolling my web logs pays off.

It's actually neat to watching someone going through all the same steps I did, from the initial install and impressions and then on to the analysis of the boost curves and what not. I didn't get much into the fact that it's entirely non-parasitic boost here, but he makes good note of that. When it's running, it's all gain without the losses my M45 takes, which is worth noting in that the psi numbers can't be compared so directly.

It's fun to see him having the same challenge I had in trying to run down the battery.

[Vetrox]

Hmm this seems veeerrry interesting.

Could be extremely usefull on my girlfriends RX-8...it could do with a little bit extra at the lower end of the rev range