TitaniumTT's I hope I make it to DGRR '09 Build

[NoDOHC]

Just a question: Are you running a returnless fuel system, because if not, the fuel flow rate is fixed by the pump, it either goes in the injectors or through the FPR, but it always flows the same from the pump at a given fuel pressure. With the engine off, the pump should see load equivalent to 0 psi boost. Under boost, the pump has to make 13.75 psi more fuel pressure.

I think that you are on to something, but maybe not exactly as you described it above. I think that your fuel pump is overheating, which is decreasing the available fuel throughput of the pump and is starving your engine for fuel. You can boost for short spurts just fine, but the pump can't handle the 57 psi for very long without drawing more current.

One more thing, it is likely a multi-stage impeller-type pump, which means that under boost (when the pressure is higher) the flow will actually decrease due to limitations of that design, without factoring in the change in coil resistance due to temperature. (Look at turbo-map speed lines for an idea of the curve shape).

You should have a fuel pressure correction map in the Motec... If not, you can set up an inverse trim to the 0-5V input. Maybe that will avoid going lean in the future.

[TitaniumTT]

Originally Posted by NoDOHC

Just a question: Are you running a returnless fuel system, because if not, the fuel flow rate is fixed by the pump, it either goes in the injectors or through the FPR, but it always flows the same from the pump at a given fuel pressure. With the engine off, the pump should see load equivalent to 0 psi boost. Under boost, the pump has to make 13.75 psi more fuel pressure.

Nope, it's a return system. -6 Stainless return hardline. The all the pulls up till the last three showed about 55 psi of rail pressure. The filter that plugged last week, after we replaced it I drove around for 600 miles without an issue at all. I'm starting to think that the contamination is the pump disintegrating.

Originally Posted by NoDOHC

I think that you are on to something, but maybe not exactly as you described it above. I think that your fuel pump is overheating, which is decreasing the available fuel throughput of the pump and is starving your engine for fuel. You can boost for short spurts just fine, but the pump can't handle the 57 psi for very long without drawing more current.

I agreee. Which is why on my 20 minutes communtes there is no issue or when I drive 150 miles to Daves and cruise down the highway at ~36psi of rail pressure and very little flow, there is no problem. But pull after pull after pull just over works the pump.

Originally Posted by NoDOHC

One more thing, it is likely a multi-stage impeller-type pump, which means that under boost (when the pressure is higher) the flow will actually decrease due to limitations of that design, without factoring in the change in coil resistance due to temperature. (Look at turbo-map speed lines for an idea of the curve shape).

Not sure of the type of pump that it is. Same as all the others I'd imagine.

Originally Posted by NoDOHC

You should have a fuel pressure correction map in the Motec... If not, you can set up an inverse trim to the 0-5V input. Maybe that will avoid going lean in the future.

I do, I've looked at it, and I've already started working on some sort of correction MAP. The only problem is, and admitatdy I haven't spent a great deal of time on it, if we see down to 31 ish psi, there isn't a problem, when under decel. So I'm still pondering how to input the table to account for the needed fluctuations in boost. It'll come to me one night at 3 in the morning when I can't sleep.

[NoDOHC]

It is an easy map.

According to our buddy Bernoulli, Fluid flowing through an orifice (fuel delivered) is proportional to the square root of the differential pressure (should be 43 psi for you). This is fixed as the fuel pressure is biased to the manifold pressure, thus the pressure drop across the injector is always constant.

Thus, you would flow 1.41 Times as much fuel at 43 psi as you would at 21.5 psi.

The map should be very easy to plot.

EDIT:

Whoops! I forgot about a factor that will make the map extremely difficult, you are not measuring differential pressure, you are measuring gauge pressure and absolute pressure in the manifold. This math will be a little more complicated.

If you have a barometric pressure input to the Motec, you can configure a Math channel (I think that a Motec will do this). Set the math channel to Differential_Pressure = Fuel pressure + Barometric pressure - (Manifold pressure (in kPA) * 0.145). If you don't have barometric pressure, call it 14.7 psi and you will be close enough.

Now you can use the above relationship to compute your fueling correction parameters and avoid engine damage (we would all be very sad to hear that you damaged the engine while you were checking the local dyno against Dave's).

Another edit due to random thought while at work:

If your fuel pump would ever run out of capacity, it would be at maximum RPM and maximum boost. I think I explained this earlier, I just got to thinking that my previous post was slightly confusing. If the fuel pressure is dropping before the filter, the fuel pump has to be the weak link. A good way to test this would be to pressurize the FPR with a bicycle pump or something to 15 psi and let the fuel pump run for a while. If the pressure starts to drop relative to the bike pump (should run 43 psi above pressure from bike pump consistently). This means that your Fuel pump can not make that much pressure, even at 0 flow (the FPR will eventually shut the fuel flow though it off completely as the fuel pressure is dropping). If the fuel pump can maintain the pressure, The next calculation that you need to make is the maximum flow that you achieved through your injectors (which should be straight forward if you know the injector size).

Next, you will need to get a graduated cylinder and take off the return line from the fuel rail to the fuel tank and feed it into the cylinder. Keeping the bicycle pump at full boost (~15 psi) measure the flow rate that the pump is able to make. Time how long it takes the pump to fill the graduated cylinder 3/4 full. This could take a minute or so, depending on the size of your graduated cylinder, Several liters would be better (I use a 5-gallon pump calibrators bucket).

Armed with this information, you will know conclusively if your pump can indeed supply enough fuel to the engine.

If I were you, I would run the pump for a couple minutes and then retry the flow test (you will need two ball valves to change the FPR return location quickly).

[TitaniumTT]

Originally Posted by Slammedred7

Man....good thread. Looks really sharp!

Thanks man.

Originally Posted by NoDOHC

EDIT:

That was a good edit, worthy of it's own post because I almost didn't see it. The one thing that you forgot to mention is A draw from the pump as well. This is what I've been doing the last few nights is checking flow, A draw, and pressure before and after the filter.

So far I have concluded that my Cosmo pump has puked. It's drawing 12.5A @12v and 15 A @ 13.5V. The fucker is gone. In fact, the dicoloration that I'm seeing in the filter is most likely chunks of magnet getting spit out - per a theory from the Aeromotive tech that I spoke too who has actually seen that happen. My theory is this, I know I have had epoxy clogged filters in the past, you could peel it off the filter. So, I believe that the filter brought up the delta acorss itself so high that the pump just overworked itself. This is what cost engine #3. Prior to going to the dyno I had been running a Bosch 044 but MY GAWD is that fucker loud. The night before I put the Cosmo pump back in (pressure had been fine with the Bosch pump all the way to redline running pig rich) and drove out to Dave. On the drive out the Fuel Pressure sender puked. First pull she went way lean and warped 2 Apex seals. On the drive home I had to stop a few times to add fuel to the entire map to stay on the safe side of stoich. This also happened a few times on some longer road trips. I thought the filter was just clogging, in fact, I think the pump was just getting hotter and hotter and hotter (scary thought actually)

So got home from fragging engine #3 and in fact the filter was clogged with epoxy. Cleaned that thing out and continued to run the same pump ASSuming it was the filter Fastforward to this weeks adventures and towards the end of the day the "filter clogged" Changed it out (let the pump relax for ~45 minutes) and made one pull and alls well, go for the money pull (she did do 402.77) and the "filter clogged" again. Without changing the filter I'm testing the delta and it's actually ~.3psi less BEFORE the filter. Here's why I think that is. At the reg I'm using a 100psi sender and 10" of -3 line. Before the filter I'm using a 250psi sender and 4' of -4 line (all I had) So given the extra length to travel, and the lower resolution of the 250psi sender, I'm saying they are damn close and the delta is virtually unmeasurable as it should be with a filter with 150 miles and 2 dyno pulls.

Think about what we're asking the pump to do on the dyno though, run 56 psi basically all day long. Now in speaking with Dave he has run the Cosmo pump all the way to 500rwhp. Not the greatest but it does. We're also using the same pressures as well. The only 2 Cosmo pumps that he's seen fail were sugared. It's a good pump, but I don't think I'll be buying a new one just becuase it broke once (although the circumstances sucked) but I don't like replacing broken parts with the same thing.

So I've tested the Cosmo pump and it failed.
I tested my Bosch pump and it works, but loud as fuck
I have my buddies Walbro GSS341 which flows enough that I am testing tonight. If it's considerably quiter than the Bosch and holds pressure and flow, I'll run that until I can find my ultimate pump. I'm thinking it's going to the Apexi BNR33 or is it 32? Dunno but something like that. I want... need a quite pump. Bosch is too damn loud. Flows like a bejuzus but loud as hell.

So, off to install a Walbro now

[vex]

B- could you shoot some close ups of your ducting work/radiator mounts and post them up? I'm planning on beginning that taken care of on mine sooner rather than later.

[TitaniumTT]

Sorry man, only pics I got I already posted. Tell ya what, bring the rig up here and I'll build it for ya after 1/1/10

Ask any questions that you want though. I LOVE the setup but honestly I went too big. My coolant temps never get above 173* on the highway and on my last trip to Dave my oil temps were @ 139*!!! That's honestly too cold. I'm thinking about building some muffs but when I sit in traffic, the oil temps get up there, and by up there I mean 210*. The only time my coolant temps ever got about 187* was sitting on the rollers for the emmisions test.... then both water and coolant hit something like 265* and chunked the rear/rear side seal

[vex]

Originally Posted by TitaniumTT

Sorry man, only pics I got I already posted. Tell ya what, bring the rig up here and I'll build it for ya after 1/1/10

If you're serious I may take you up on it. School right now is kicking my trash (Astro-Mechanics, Thin-Walled Structures, Vehicle Vibrations and Controls, Thermo Dynamics, Aero/HydroDynamics, with a manufacturing processes lab for fun). I'm aiming to get something put together next weekend and I think I have a design in mind--we'll see though.

Once I have that and the scavenge pump in I can start concentrating on the important things (ECU, and custom manifold). But I imagine that this car won't be "done" until I'm in my own house and can actually take it completely apart and build it from the ground up.

PS, I demand more pictures/movies. Or I may just have to send you a hooker to bribe them out of you.

[TitaniumTT]

Originally Posted by vex

If you're serious I may take you up on it. School right now is kicking my trash (Astro-Mechanics, Thin-Walled Structures, Vehicle Vibrations and Controls, Thermo Dynamics, Aero/HydroDynamics, with a manufacturing processes lab for fun). I'm aiming to get something put together next weekend and I think I have a design in mind--we'll see though.

Once I have that and the scavenge pump in I can start concentrating on the important things (ECU, and custom manifold). But I imagine that this car won't be "done" until I'm in my own house and can actually take it completely apart and build it from the ground up.

PS, I demand more pictures/movies. Or I may just have to send you a hooker to bribe them out of you.

Dead serious. PM me if you want to chat about it. We'll definately be able to work something out though.

[Slammedred7]

Man....good thread. Looks really sharp!

[EJayCe996]

Originally Posted by Slammedred7

Man....good thread. Looks really sharp!

GTFO, Eric

LOL you're gonna have me praying my modified supra pump never has issues although i haven't heard much about anyone having problems with em.

[TitaniumTT]

Per Dave, the TT Supra pump IS the Cosmo pump. He loves the Cosmo pump.

[TitaniumTT]

Going for a test drive. If the flow holds @ max boost, Walbro pump - believe it or not - takes it. Mainly becuase the A draw is about 75% of the Bosch and the noise.... oh thankfully it's so much quiter than the Bosch.

Although, 2nd gear pull on race tires in the rain is going to be sketchy. I loose traction by 5500 in the dry If there's a problem to have, traction is a good one to have

[NoDOHC]

I was hoping that it was just the pump and not plugged injectors, or overheating injectors, or debris in the FPR (so that it can't close completely), or sugar in the fuel tank, or some other weird issue that I haven't seen yet.

Large injectors are very expensive, so anything injector related would have been very bad news.

I am interested to see a dyno graph on the sequential turbos after you get them tuned.

Did you port the turbos or do anything to them? I have a set of Twins that I have had forever (I don't even remember why or where I got them). I checked them over today and they appear to be in good shape. I might go that route after your inspiring example.

(First I should learn to work as hard and fast as you and get around to replacing my rotors. I seem to lack motivation because the car runs fine right now.)

[TitaniumTT]

Originally Posted by NoDOHC

I was hoping that it was just the pump and not plugged injectors, or overheating injectors, or debris in the FPR (so that it can't close completely), or sugar in the fuel tank, or some other weird issue that I haven't seen yet.

Large injectors are very expensive, so anything injector related would have been very bad news.

I am interested to see a dyno graph on the sequential turbos after you get them tuned.

Did you port the turbos or do anything to them? I have a set of Twins that I have had forever (I don't even remember why or where I got them). I checked them over today and they appear to be in good shape. I might go that route after your inspiring example.

(First I should learn to work as hard and fast as you and get around to replacing my rotors. I seem to lack motivation because the car runs fine right now.)

Why thank you. I would definately consider them, I love them, even run non-sequentially they make great power. If the gearbox was a little better geared there would really be no need for the sequentials but alas, not yet. Really was prominent today at the auto-x

The only thing that I did to the turbo's was port the WG, replace the flapper, and ease the opening into that area. Other than tha, they are bone stock.

The injectors aren't that bad, ~$65 each I think? Although they are getting replaced over the winter I believe. We were touching 89% duty cycle on the 403 run with another pound to add. i may be upgrading the injectors and the ignition over the winter as well. We'll see what happens if we can ever get a clean dyno day out of her

[Turbo II Rotor]

How loud are those 044's? I'm gonna have 2 of them in my hatch feeding off a surge tank. Sounds like I might have to make an insulation box around them.