As most of you guys know, a gen 2 Busa will make 230whp off a 4.5psi spring on 93 pump gas... well that is until you try tuning one on VP E98. I’m still blown away by this result.
Not your typical stage 1 gen 2 Hayabusa
- Thread starter Boosted Cycle Perf
- Start date
50 whp from different fuel! Wow
Is VP E98 an ethonal fuel?
We don't have that in my area.
Is VP E98 an ethonal fuel?
We don't have that in my area.
Mathewrussell52
Registered
Wow can you explain how? I know it’s alcohol but it’s not oxygenated. It must not take tons of fuel as running stock injectors.
Does a 4.5lb spring usually run 5.6lbs?
Does a 4.5lb spring usually run 5.6lbs?
Factory stock. For a moment, forget the bike made what it did. Boost level, and ignition timing wise everything is exactly the same as if this bike were to be tuned on 93.
The reason stock gen 2s are limited to such low boost is their stock compression ratio, and very light seat pressure valve springs.
While yes the bike makes surprisingly more power on e98, it’s not pushing the limits of why we have to keep boost so low in the first place. In fact, I’d debate anyone that it’s actually safer because ethanol burns so cool, it vastly reduces any chance of detonation at the proper afr.
Yep, unless you have a textbook correct wastegate priority configuration you’ll almost never see exactly what wastegate spring pressure is rated for. Because of space it’s nearly impossible to achieve that textbook set up on a bike. RCC does an excellent job on porting the turbine housings to keep boost so close to what spring pressure is. Honestly 1psi over rated is better then most guys can get with a lot more mounting locations in the car world.
As far as HP, I’m no stranger to e85/e98 fuels. Both my race cars run those fuels, and I’ve set up and tuned several other cars on the fuel as well. I knew for a fact that it was gonna pick up power. But from my experience with turbo cars is those gains are usually seen from ability to run more ignition timing advance because of the fuels resistance to detonation. These fuels burn extremely cool, and come in at around 105-108 octane.
With that being said, on this bike from 75% throttle on up, there has been zero ignition advance added. The same exact timing as if it were on 93. THATS what I’m most surprised with. Actually adding some in, and pulling some out didn’t effect HP by more then +/- 1hp. So it was happy with stock values. The biggest jumps in HP directly correlated with afr. Tuning on the gas scale, back to back runs it sits at 11.7-11.8 which is safe on 93, and actually still a bit rich for ethanol.
And it took everything those stock injectors had. 90% duty cycle at redline.
Same as e85. (85% ethanol) but it’s e98. 98% ethanol.
SSGT_B
Registered
So you said the target afr remained the same correct? No timing adjustments? E85 or 98 has a different stoic value than gasoline. I don’t know crap about tuning bikes however I did the tuning on my TT Vette and for the Alcohol Vs Gas tunes the afr was vastly different as well as the timing. Please don’t misunderstand I am not questioning your ability, I am just trying to understand differences between the cars and bike.
Mr Brown
Registered
I'm amazed at the results. I was under the impression that Gen 2's couldn't get much over 230 hp without engine work. I wonder what would the difference be on pump E85? I realize that stuff isn't consistent, but could it be tuned to safely compensate for variation in the fuel?
No you’re absolutely right, and that is a valid question. I actually just had the same conversation with a guy on Instagram.
Fundamentally tuning is the same between bikes and cars. The key is to know the specific platforms personalities. You being in the LS world know all about how picky they are with timing when you’re playing with boost. (I have a 200k plus sbe 4.8 in my mustang that’s seen 1k HP more times then I can count. Been going strong for 4 years)
Lots of guys like to switch back and forth between gasoline scale, and ethanol scale because of the fuels stoic. However back in the day when aem came out with their first full flex fuel stand alone ecu s I just became accustomed to tuning both fuels in the gasoline scale. When it comes to the blend table, it’s gotta be one or the other.
So in reality tuning ethanol on the gas scale really gives you a decent extra safety buffer. In this case, 11.8 really I could safely lean it out further without any problems and boy does this fuel like it. The first full pull was a 11.4 average, and made 261hp. So going up to 11.8 picked up 15whp without a sweat.
As far as ignition timing goes I did add 5* to the whole map, below 75% throttle. You have to do that on everything being converted to ethanol in my experience otherwise they take forever to start, aren’t responsive, and or don’t idle well. My strategy was I know from 75% on, timing is safe for pump fuel so it’s plenty good for ethanol. Then once I got the afrs close, then I’d try sprinkling in a little extra timing up top to see how it picks up. That turned out to be a good judgment call. I put one degree in, and gained one HP. Added one more, and gained one more HP.
Again, referencing the ls world, if you’ve ever watch Matt Happel on sloppy mechanics he always used to talk about the point of diminishing gains in regards to playing with ignition timing. Add a degree at a time and see how power changes. If you add one degree and pick up 12hp, add another. Say it picks up 11. Okay, add another, and it picks up 7.... okay maybe try adding one more and it only picks up 3hp. That’s when you know you’re getting close to having too much in, and are going to start risking detonation. Pull two degrees out, and it should be fine.
Same approach with this bike. Added one degree after peak tq, and it only picked up one HP. Added one more to be sure, and yep, one more up gained. So that showed me that it had enough timing in it. The key is to give it what it wants, not what the internet says it should take. And when you take an approach like how I just did it always takes longer, but it’s worth it when the customer has years of trouble free fun.
Stock pistons and rods hold out just fine to 320hp.
The main reasons to keeping the boost low is because of the high compression. The higher the compression with boost the more prone you could be to pushing a head gasket. But even more important you’ll quickly reach a point where 93 isn’t enough octane and start running in to detonation.
Valve springs are the other concern. They have low seat pressures. You run the risk of blowing the valves open if you have too much boost with stock springs.
busakiller
Registered
Would this be a better fuel to use compared to c16? For a built motor non intercooled set up. Or is c16 the best option to use for non intercooled.
Tbh i can’t say yes or no to that. C16 is specially made for high boost non Intercooled engines. I could ramble on back an forth about theory but it all comes down to numbers.
I will say this. Since there’s no chance of a gen 3, I’m going to go out a buy a bike this weekend. I need my own bike again to test new products that are being made in house. But rest assured there’s a lot of things I’m willingly going to test to the absolute limits or even failure. But after yesterday’s results, I’m definitely going to investigate this fuel further.
That's an awesome guinea pig......
Johnnie Phatt
Registered
We should all be so lucky to have such a nice looker.
Similar threads
