Pre & Post Dyno from my Atom 2

[shinoo]

Here is the results of our upgrades and tuning on my Atom.  This is the safe level of power that can be extracted from a stock LSJ.  We tweaked the redline up and adjusted the pedal progression to make it smoother at low speed - no more herky jerky around town driving.  My car has Tom's intake, a 76mm pulley and 42# injectors.  Note we used K&N Engineering's dyno for both tests.  The car is wicked fast - with Tom's added intercooler, heat soak seems a thing of the past.

[McFred]

Neat!  Did you take advantage of the dyno to see what happens with a few 4th gear runs in quick succession?  Does it stay ~240whp with a steady air/fuel ratio?

[s996]

is your atom a 245 or a 300?  what is the going rate (HP )for an unmodded 300?  Predictions for a standard 300 with your intercooler?  what is with the heatsoak problems? is this heatsoak affecting normal trackday fun?

[Terry Kennedy]

[quote="s996"]what is the going rate (HP )for an unmodded 300?[/quote]

My stock Brammo Ecotec Atom 300 w/ 91 octane:



Since then I've switched exhausts (to Shinoo's), which should help somewhat.

[s996]

why do  they call them the 300?

Am I missing something.  What would the 245 do?

[Terry Kennedy]

why do  they call them the 300?

Brammo? Either ignorance or malice. Both theories have been floated with reasonable supporting evidence in the past.

Am I missing something.  What would the 245 do?

About the same. The "Fix" for the Brammo 300's was to essentially downgrade them to 245's.

[DarthChicken]

which is why a few of us went our own rout after a while to get the missing power.  S996 pm me for more info.

[s996]

I guess they may claim 300 at the flywheel but mechanical losses resulting in 80 hp loss at the wheels sounds very high.-about 25%

I would suspect drive losses of about 10% at most.

Do the mods bring the engine up to 300 without replacing major components? sc/pistons/turbo?

[Heywood-Yablowme]

I believe it was wishfull thinking mostly,on both GM and brammos part.They may have apporached 300hp on an engine dyno back at GM,with who knows what kind of exhaust,fuel,coolers etc.
They weren't bad..they just didn't have the 300 people paid for. Money for nothing.Did not help out the brammo reputation at all,especially the Upgrade-slash-downgrade "solution".

Well,that's all old history anyway.    300whp is not that hard to achieve, if you need it. Just takes a bit of money and wrenching

Turbo,TVS,twin charge..it's all good.

[s996]

Thanks guys for the history

I learning. 

Let me learn to drive this 222 / 300 and then I when I need a little more I will buy the "magic dust" that you add to the tank to make it faster.

[Terry Kennedy]

[quote="MadMaxAtom and company"]
I believe it was wishfull thinking mostly,on both GM and brammos part.They may have apporached 300hp on an engine dyno back at GM,with who knows what kind of exhaust,fuel,coolers etc.[/quote]

GM knew exactly what horsepower (260 on 100 octane) their LSJ Stage 3 kit produced and what it required (93 octane fuel).

I can believe that they had hopes that the setup they prepared for the Atom would do better than that - after all, the Atom has a much shorter and less constricted exhaust, no parasitic loss from an A/C compressor, a different intercooler pump, and so forth.

Brammo was always very secretive on what they were doing with the engines in the various HP ranges. But it was obvious to anyone who visited them that they weren't opening up engines and changing the internals. The only special part that has been confirmed (other than the ECU) is the dual pass end plate on the intercooler. But they were modifying the stock plates instead of using the GM Tuning version.

Oregon is a 91 Octane state (as is most of the western US). So HP numbers achieved in Detroit couldn't be matched in Oregon, on street gas at least.

By the time enough owners of the "300" were asking where their horsepower was, GM had long since decided to discontinue the LSJ in favor of the turbocharged model, so there probably wasn't a lot of interest at GM in finding the missing HP.

[DarthChicken]

Oregon is a 92 octane state Terry.  And its "good" 92 octane, unlike Washington's 92 octane, which acts more like 91.

Regardless, its not 93.  As much as I'd like to be angry at GM, the problem was with Brammo, and always was.  They knew that the sum of their parts was never going to make it to the magic number.

(breath.. relax.. let it go.. its ok... breath...)

[NormLarson]

I have seen it vary considerably or at the very least noticeably from station to station and definitely from brand to brand.  I was told one time it could vary a lot by something as simple as how often they change their filters.  I have no idea if that is true.  Basically not all "92" is the same ...

[Terry Kennedy]

[quote="DarthChicken"]
Oregon is a 92 octane state Terry.[/quote]

Ok. I must have been confused because of the "we assume you're too stupid to pump your own gas" law, which we also have in NJ (the only 2), and it being close to the California Conspiracy of pseudo-91 gas.

NJ is nominally a 93 state, though sometimes 94 shows up. I'm spoiled, though - I have 2 places that carry 100 (Sunoco 260 GT) reasonably close by.

IN is a 94 state.

I think SD is 91 or 92, but a number of stations switch to 93 or 94 around Bike Week (I came though about 2 weeks after it ended in 2007 and was chatting w/ a station owner who does around 5000 gallons/week of 94 during Bike Week and only around 100/week the rest of the year.

On my 2nd trip back from Brammo in 2007 I took the northern route back, and in one of the uninhabited states I pulled off the highway for gas. The pump offered 83/85/87 and was out of 87, so I decided to wait for the next station. That turned out to be another 50 miles or so down the highway and had one of those "directions at exit" signs. Turns out the "station" was about 10 miles down a dirt road and was a lone pump serving 83 with a paper note saying "multiply all readings by 4" taped to the inside of the glass, because it had never been re-geared for gas over 99 cents/gallon. It was padlocked and I had to go into the bar (yes, this was in the front yard of a bar) and wait for a slow time at the bar before the bartender would come out, take my cash, and unlock it.