Full throttle Electric Supercharger Build Thread

[fenton]

Originally Posted by Toma

Correction? Tough call on that one. They were never intended for forced induction applications. Depends on what the supercharger does I guess.

I won't predict an outcome lol. Interested to see what happens.

I think they are wondering if your dyno added the boost to get the number we got?

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[fenton]

I know that a dyno can correct for the difference in a NA car between sea level and our altitude.

So that means that my car made 168 HP stock at sea level even when in reality it would not be putting that down to the wheels at our altitude.

The charger physically isn't able to make the same boost at our altitude so nothing can be corrected that does not exist.

[fenton]

Originally Posted by Robftss

6. Correction factors are for outright numbers only. The only important info from the dyno is the delta gains in % from stock to mod at various rpms. This is what the driver will 'feel'.

7. Comparing 1/4 mile times has to be done with the same car same place same time to be valid. 1/4 mile or any timed performance done a two different relative densities will be not comparable. A stock FRS will do 17 sec in Denver and 14.5 sec at SL (very approximate).

This pretty much says it all, no sense speculating until someone tosses it on a dyno at sea level

[Wonderbar]

Originally Posted by fenton

I know that a dyno can correct for the difference in a NA car between sea level and our altitude.

So that means that my car made 168 HP stock at sea level even when in reality it would not be putting that down to the wheels at our altitude.

The charger physically isn't able to make the same boost at our altitude so nothing can be corrected that does not exist.

No charger will, but forced air loses less % of power at altitude than an NA motor. Turbos and s/c were actually designed for use in piston powered aircraft motors to still have power at flying altitudes.

Example; when I was in Colorado Springs, an NA car would lose about 18% horsepower when compared to the same NA car at sea level. A turbo car would only lose about 5% and a supercharged car about 4-5%.

[Fast_Freddy]

Originally Posted by FT_Monk

17:1 is possible when throttle lift off, don't know the AFR was measured with a wide band.

Yes but who cares what the AFR is during coasting fuel cut? It gets a lot leaner than 17:1 if you coast long enough.

Originally Posted by Dustin2JZ

Just going by what Fenton posted.
Seems quite high to me too.

Fenton & Rob. We need clarity please

I think it's reasonable to assume that a mistake was made. Rob's explanation clears things up to my satisfaction.

Originally Posted by fenton

The simple point is the power being made at 1.6 psi on a otherwise stock car.

Its not at all a stretch to say we might make another 20 hp or so with some supporting mods or a little bit more boost if it is possible. Just look at the vortech unit with a FA20club header, huge gains.

I could see you calling me out for BS if i was saying >250 with exhaust mods.

Just as an FYI when we hooked up an additional battery(2 very small ones) we made 210whp but Rob didnt want me to post that one as he isnt sure if the packaging will work as he likes.

All information about the kit is being shared freely here, i will wait for @Toma to answer the dyno correction questions.

I believe there are some guys at Sea Level that should be getting the kit soon and i hope to see them post up here as well

I was afraid that I wasn't clear enough. I didn't mean to accuse you or Rob of spreading BS about this e-charger, not at all. You may be understandably enthusiastic and possibly even a bit optimistic about it but Rob has been nothing but factual thus far and I really appreciate how both of you have been handling this thread. The BS that I referred to was from other members posting in this thread.

Anyway, enough of this for now. I'm looking forward to some new performance data and tune info.

[PantsDants]

Originally Posted by Robftss

3. Check engine light @ 3000 rpm tripped by ECU, Fenton had 2 codes relating to the transducer and a load calc. No intervention made by ECU , Ie timing or knock etc. , CEL off shortly after. Toma modified trip with Brz Edit.

4. Below 2000 rpm, rich and timing pull. An rpm window switch to deploy boost ~ 3000 rpm would ensure stock tune operation. A NOS window switch, which there are several available, can be installed as per the instruction of the manufacturer of the device the same as you would a NOS system.

So would something like http://www.jegs.com/i/JEGS-Performan...rentProductId= wired in-line with the accelerator switch work to prevent activation below 3k rpm? This is assuming that a tuning solution won't be shipping with the kit.

[mid_life_crisis]

It should, but do we know for sure that disabling the system below 3000 rpm would prevent the cell?

[mid_life_crisis]

@fenton
I can't find how you ended up implementing the engagement switch. Is it monitoring a voltage level or is it a physical switch that you bolted in somewhere?
I'm sure it's mentioned somewhere in the thread, but there are way too many pages to read them all again looking for it.

[SloS14]

Originally Posted by mid_life_crisis

@fenton
I can't find how you ended up implementing the engagement switch. Is it monitoring a voltage level or is it a physical switch that you bolted in somewhere?

looks like a switch

[Robftss]

Originally Posted by Wonderbar

No charger will, but forced air loses less % of power at altitude than an NA motor. Turbos and s/c were actually designed for use in piston powered aircraft motors to still have power at flying altitudes.

Example; when I was in Colorado Springs, an NA car would lose about 18% horsepower when compared to the same NA car at sea level. A turbo car would only lose about 5% and a supercharged car about 4-5%.

Well, in theory here is how altitude effects N/A and FI (temp and dew point being constant) you have to use absolute station pressures, with SL (14.5 psi) & ~4000' (13 psi) and 5 psi gauge for FI as an example.

N/A: 14.5/13 = -11.5%

Turbo with gauge reference: 19.5/18 = -8.3%

Turbo with abs reference (BMW, Audi, others?): 19.5/~19.5 = ~ 0%

Mech super: 19.5/17.5 = -11.5% *fixed speed relation to engine so PR applies. so 5psi @ SL will be 4.5psi @ 4000'.

FTS 19.5/17.75 = -10% (compressor rpm increases slightly due to lower density @ altitude, so PR is up, ~ 1/2 way between a turbo an mech super)


SC piston aircraft (WW II) had 2 gear ratios (low alt and high alt) since it does not compensate for altitude. Modern turbo aircraft engines primarily 'turbo normalize' to maintain +SL performance regardless of elevation.

So..Fenton racing a BMW 135i which can maintain nearly zero loss @ altitude..nice!

Rob

[Wonderbar]

^ good find.

As for your e-charger at altitude, I bet it is making up some of your atmospheric differences and making it feel even better than when you were NA. 3500 feet isnt going to have nearly the strain that 6400 feet of Colorado Springs but will still make a stock BRZ/frs even more sluggish.

[fenton]

Originally Posted by mid_life_crisis

@fenton
I can't find how you ended up implementing the engagement switch. Is it monitoring a voltage level or is it a physical switch that you bolted in somewhere?
I'm sure it's mentioned somewhere in the thread, but there are way too many pages to read them all again looking for it.

Its a nitrous style WOT switch engage by physical contact of the accelerator pedal with the switch.

As for your other question, a window switch with 3000 engagement will not get rid of the CEL.

Yes you probably wont get a CEL in first or second but in third and greater going WOT at 3000 to 4000 will result in the CEL coming on. I drove the car like this for 3 weeks and it didnt have any ill effects other than the light coming on.

The tune gets ride of the CEL for good though.

[Robftss]

Originally Posted by Wonderbar

^ good find.

As for your e-charger at altitude, I bet it is making up some of your atmospheric differences and making it feel even better than when you were NA. 3500 feet isnt going to have nearly the strain that 6400 feet of Colorado Springs but will still make a stock BRZ/frs even more sluggish.

e-charger or mechanical supercharger will provide essentially the same "making up for some atms differences". Regardless of relative density @ various altitudes the delta gains will be similar, peak #'s with the FTS will be +~35% TQ and +~20% HP. Through some of the 'useable' rpm range over 50% is achieved.
Again, centri or positive displacement SC do not compensate for altitude, unless provisions are made (Audi 3.0 SC) to recirculate some pressure.

[Wonderbar]

Originally Posted by Robftss

e-charger or mechanical supercharger will provide essentially the same "making up for some atms differences". Regardless of relative density @ various altitudes the delta gains will be similar, peak #'s with the FTS will be +~35% TQ and +~20% HP. Through some of the 'useable' rpm range over 50% is achieved.
Again, centri or positive displacement SC do not compensate for altitude, unless provisions are made (Audi 3.0 SC) to recirculate some pressure.

Without coming across as insulting, I think we are agreeing in a circular manner with slightly different details.

In theory long as the system stays sealed and uses a recirculating bov setup, then the pressure stays an even constant. But both superchargers and turbochargers compress air the same way and as long as its a sealed system they work the same way. They both have the same effects at negating altitude for an internal combustion motor simply because they are forcing more air into the same volume, essentially making the thinner air at altitude a non issue and keeping the power output of the motor in a range of normalcy.

The reason for two-step superchargers was to prevent over boosting at low altitudes since boost is mechanically controlled through gear ratio as opposed to pressure release valves.

Roughly 10psi at sea level is the same as 30psi at 30,000 feet. Pretty good section on altitude effects.

Again, I think we are agreed, just having a discussion on the topic.

http://en.m.wikipedia.org/wiki/Supercharger

Since the E-charger doesn't have a bov or anything, once the air is compressed and blown towards the TB, it will stay the same pressure even on throttle let off. The issue you run into then is compressor back surge, which is a whole separate issue, but I think since the charger disengages when not powered, I assume the air pressure will just back itself into the airbox through the compressor.