Project Thread Supercharged Supra

[cribbj]

Mitch logged most of the runs, but we may have some difficulty correlating them to Dennis' data. I neglected to get Mitch's data before he left, but he's going to email it to me, and I'll sift through it as time permits and transpose it to the Excel spreadsheet. He captured boost, AFR, charge air temp, coolant temp, etc.

What really would have been useful would have been the BSFC data that Dennis usually gets, but this time he didn't due to a slipup in his fueling configuration. I won't allow that to happen again, and will furnish the fuel pump next time.

If we'd had the BSFC data, we could have spotted straightaway if we were blowing too much energy out the exhaust. We already know this motor is capable of 0.50 to 0.55 lbs/hp-hr as it did these levels last time.

 

[Lextreme II]

WOW... nice torque curve....

 

[Cobber]

Love that torque and looks like it may even be even fatter at lower rpm.

Godd one John you have inspired me to spend the rest of the day in the shed.

 

[JBrady]

If we'd had the BSFC data, we could have spotted straightaway if we were blowing too much energy out the exhaust. We already know this motor is capable of 0.50 to 0.55 lbs/hp-hr as it did these levels last time.

Following from post #277 on page 14

The 460cc injector duties approached 90% as we hit 498 HP, even with us dumping 600ml/min of straight methanol into the system, so to go much higher than 500 HP even with meth injection is going to require larger injectors.

Go to the following link, bottom of page, fuel injector calculation worksheet

http://www.rceng.com/technical.aspx

First calc
HP goal = 500
Num Inj = 8
BSFC = .55
Duty = 80%
Fuel pressure = 60psi

Injector size required = 37 lb / 385cc

Your 460cc injectors at 90% spec out to 675 hp...

175hp worth of fuel is missing somewhere...

 

[turboandrew]

90 hp lost for driving that SC

 

[JBrady]

90 hp lost for driving that SC

90 sounds high but still leaves 85hp of gasoline and an unknown quantity for methanol.

 

[stevechumo]

I thought with turbocharge/supercharge engine, it must be multiplied by .60 BSFC.

Therefore, (500 hp x .60) / 6.4 = 46.87 lb/hr per injector => 46.87 x 10.5 => 492 cc/min per injector. This is the safe side.

 

[JBrady]

I thought with turbocharge/supercharge engine, it must be multiplied by .60 BSFC.

Therefore, (500 hp x .60) / 6.4 = 46.87 lb/hr per injector => 46.87 x 10.5 => 492 cc/min per injector. This is the safe side.

Steve, the .60 BSFC is rule of thumb for safety. John and Dennis already determined that this engine works well at .55 and even .50 BSFC.

We already know this motor is capable of 0.50 to 0.55 lbs/hp-hr as it did these levels last time.

The most recent dyno runs showed the injector duty cycle at 90%.

Many think that a FPR that matches boost keeps flow constant. Injectors are hydraulic devices and the pressure port or rail opening is larger than the outlet orifice. This multiplies pressure and way more than overcomes just the boost increase for delta P. John mentions fuel rail pressure at 60psi as aposed to the standard rated flow pressure of 43.5psi.

Also as mentioned there was methanol (fuel) being injected) negating some fuel requirements.

Now, lets talk ONE injector. 1/8th of 500hp = 62.5hp per injector.

That needs about 43lb/hr injectors at .55 bsfc and 80% duty cycle at 43.5psi rail pressure.

Increase that rail pressure to 60psi and the increased flow reduces injector size required for the same power to 36lb injectors.

460cc injector at .55, 80% and 60psi supports 75hp (75 x 8 injectors= 600hp)

Now, as said they reached 90% duty cycle. 460cc, .55, 90%, 60psi = 84hp ( 84 x 8 inj = 672hp)

And at .50 BSFC, 460cc, 90%, 60psi = 94hp (92hp x 8 inj = 736hp)

This is NOT including the Meth.

So, without the meth and granting a pretty large 90hp blower drive allowance (probably less) still leaves nearly 150hp unaccounted for at .50, 84hp at .55

 

[Zuffen]

JBrady,

I was thinking the same thing myself.

The Meth should have been adding a serious amount of power to the equation.

From memeory John was feeding the engine around 500cc per minute which is like an extra injector.

My leaning is toward the cams being too agressive and shoving the mix straight out the exhaust.

Milder cams should equal more (much more) power.

 

[JustenGT8]

Not much meth in the scheme of things so doubt it's adding bugger all to the total power in combustion.......intake density and burn control is where it's doing it's thing.

 

[turboandrew]

Well, it's gotta be either ignition timing or cam timing. I can see both having a major impact. Ignition timing seems easier to test What was the timing on the near 500 HP run?

 

[cjsupra90]

Quote:
Originally Posted by stevechumo
I thought with turbocharge/supercharge engine, it must be multiplied by .60 BSFC.

Therefore, (500 hp x .60) / 6.4 = 46.87 lb/hr per injector => 46.87 x 10.5 => 492 cc/min per injector. This is the safe side.

Steve, the .60 BSFC is rule of thumb for safety. John and Dennis already determined that this engine works well at .55 and even .50 BSFC.

Another thing to add to this is that all the quoted BSFC figures (or value's) that are still used to this day are still based on older less effiencent engines. As technology has advanced and engines have become more effiencent, BSFC figures (or value's) drop for the same given power output.

 

[stevechumo]

Another thing to add to this is that all the quoted BSFC figures (or value's) that are still used to this day are still based on older less effiencent engines. As technology has advanced and engines have become more effiencent, BSFC figures (or value's) drop for the same given power output.

This is a good point. It also depends on several factors such as electronic fuel controller, the position of the fuel injector, the injector's efficiency by itself, and correct tuning...etc. I'm not an expert in tuning so I just follow the formula that we have available. I think as long as the A/F ratio is correct, then the BSFC that is used to tune it is already correct.

 

[cribbj]

Lots of good commentary here. I appreciate everyone's thoughts & ideas.

BSFC: on the dyno runs last April, we had actually measured as low as 0.44 (no boost), and as high as 0.55. These were with the supercharger and a bit of M/W going in presupercharger. When I broke the motor in, naturally aspirated, with the 4bbl Holley last October, the BSFC's were between 0.44 & 0.48.

Ignition timing: for the 498 BHP run it was 27 degrees, IIRC. Between 25 and 28 "seemed" to be the sweet spot for this motor.

Meth: I had both a 375ml/min and a 225ml/min nozzle in the system for the last runs. I'd already measured 500ml/min coming out of the 375 nozzle at 175psi instead of the rated 100psi. So I'm guessing we were putting between 600 and 800 cc/min of methanol into the system at full chat. Unfortunately I didn't get to see the pressure gauge on the meth system to see what it was doing, as I wasn't too keen to go into the dyno cell with the engine @ 500 BHP and 7000 RPM ;-)

Fuel Pressure: As we were having fuel pump issues, and were seeing the pressure drop off at high output, Mitch boosted the static rail pressure up to 50psi (around 40-42psi @ idle), and at 17psi of boost, we were seeing around 60psi of fuel pressure, so the injector outputs should be figured on 60-17= 43psi.

Exhaust: We were all surprised at the amount of energy coming out the exhaust. We had about 1.5 metres of flex pipe between the headers and the rigid tailpipes, and we were breaking either the left or right flex on nearly every pull. During the pull, the tailpipes would start shifting toward the motor, due to the thrust that was being produced, then that would cause the flex to bind, then break. In retrospect, I think if we had restrained the tailpipes, we might have had better luck. The cams we were running have 16 degrees more duration than stock, so it's certainly possible we were losing a lot of useful energy out the tailpipe. Plus perhaps with the difference in compression between left & right banks, they could have been installed a tooth off, or other. I've asked Dennis to find out where this difference in compression came from.

 

[Mattmannz]

Nice progress!

500hp in a street car will be great!

What fuel pump and regulator are you using? Is the reg a rising rate setup?

Cheers
Matt.

 

[JustenGT8]

Lots of good commentary here. I appreciate everyone's thoughts & ideas.

BSFC: on the dyno runs last April, we had actually measured as low as 0.44 (no boost), and as high as 0.55. These were with the supercharger and a bit of M/W going in presupercharger. When I broke the motor in, naturally aspirated, with the 4bbl Holley last October, the BSFC's were between 0.44 & 0.48.

C16 will change things quite a bit i would guess?

Ignition timing: for the 498 BHP run it was 27 degrees, IIRC. Between 25 and 28 "seemed" to be the sweet spot for this motor.

That's a heap of timing for 15psi....i run 18 deg adv at full load. Again, shows what C16 will let you achieve....Meth obviously helping too. Hmmm, if only c16 was a tad cheaper that's all i'd. Fine for drags but a day at the circuit would be getting expensive.

Unfortunately I didn't get to see the pressure gauge on the meth system to see what it was doing, as I wasn't too keen to go into the dyno cell with the engine @ 500 BHP and 7000 RPM ;-)

Wuse, i'm next to the engine bay with earmuffs listening for det on my 536rwhp runs

 

[cribbj]

Mattmanz, the fuel pressure regulator is an SX unit, with a 1:1 ratio to manifold pressure.

The dyno fuel pump was a dodgy SX unit that had seen better days, and will be replaced for the next session.

I'll be running the standard Supra fuel pump, but will be boosting the voltage up to 16v as needed and controlling it via PWM. At 16v, this pump is capable of pumping over 800 HP of fuel.

Justen, it seemed the sky was the limit with that C16. The power output really jumped once we were above 18 degrees. The engine seems to like lots of timing (when it has lots of octane).

Wuse, i'm next to the engine bay with earmuffs listening for det on my 536rwhp runs

Yeah, but you don't have to worry about two exhaust pipes that think they're rocket engines, trying to launch themselves up your arse either! :crazy:

 

[JBrady]

One of the best things about the internet is it brings so many minds to the table that problems can be thought through and real experience provided from around the world.

Take this thing back to last Thursday page 14 of this thread:

I would consider just using race gas and no meth/water to simplify the whole thing (for now). 190 degrees is a little on the hot side, but IMO not enough, with the right octane gasoline, to be such a problem. There has to be something else going on.

Is it possible to run without the supercharger and still run the fuel injection? I'd want to know exactly what this thing can do without the supercharger first. With cams (I think you added cams, right?) I would expect 300 BHP. If that can not be done, do not move forward until the HP is addressed in that configuration.

My gut feel is it's a false air temp reading. Supercharging these engines has been done many times with some very basic control systems with good results...

Turboandrew's comments about going back to basics and getting your base point is also very valid, being an engineer root cause analysis and standing back looking at the big picture is the first tool I use...

...check to see if the int. and exh. cams are timed correctly to eachother, i.e. not off a tooth or two or even possibly more and this might explain the extremely low power for running 15psi and also the strange distrabution issues especially if the distrabution issue is different from bank to bank and thus might be a head that has the cams wrong.

I bring this up cause I say a similar situation on a 1MZ-FE that had a TRD supercharger on it, and the guy had the heads rebuilt and mildly ported and the shop that did them put the cams off on one of the heads. Basically, they had the exh cam on the one head IIRC retarded by two teeth and thus created a pretty substantial amout of overlap and thus the supercharger was blowing a large portion of the A/F charge straight out the exhaust and thus that bank was down on power...

Now, posted by Greybeard but easily missed was the power requirements of the Opcom series SCs and the 420:

The 420 is shown here which will be close.

http://www.hi-flow.com/HP7Super.htm

It shows the 420 (2 liters) requiring a max of about 57kW (74 horsepower) at max flow and RPM on their map. Now the 422 is slightly larger at 2.2 liters so add 10% and that is about 80hp maximum drive loss. The graph is so small it is hard to read so not easy to tell what the flow rates and pressures are.

 

[JBrady]

More Opcom data

http://www.textiform.se/autorotor.pdf

 

[Zuffen]

Jbrady,

I have that page printed out at home.

The temp rise is only minor but John C was seeing almost 100* increase which he beat with lots of meth.

Something here doesn't make sense as he should only see a minor rise in the inlet temp.