JETPILOT

iTrader: (51)

No I'm not keeping the Z.

ttg35fort

iTrader: (2)

Jet is still trying to sell the Z, but he wants to address any flaws he has before selling it.

When I ran Sebring I lowered my boost, so I probably was right around 480-500 hp, and I was still sucking the stock swirl tank dry, even on the long straights. One option is to drill holes in it to allow more fuel flow in, but I am shooting for 700-750 hp when I tune with Meth injection, so I am beyond the limits of one Walbro.

That is why I bought the SPR tripple pump hangar. When I bought it, however, I did not realize it didn't use a swirl tank. For street use, it is fine and pushes alot of fuel. Although I don't have to worry about sucking the stock swirl tank dry, I am concerned about losing fuel pickup when the fuel sloshes to one side in high G turns. Admittedly, I have not yet tested the SPR tripple pump hangar on the track, but I will feel much more comfortable having a surge tank.

thom000001

assuming your return line is big enough, what about running all 3 pumps. But have one of the pumps run the pickup over to the other side (driver's side) instead of waiting on the venturi to catch up (takes the venturi a bit to refill the pass side saddle)?

or run the 3rd pump as the fill from driver's side to passenger side instead of the venturi.

Just a thought........

tom

TrackPack

iTrader: (1)

I could never use one to draw. But thats just me

phunk

iTrader: (21)

i could put a bosch 044 inside the surge tank... but thats going to displace some of the displacement... im not sure how small you can go and still have a decently effective setup. considering the pickup issues would be brief, and not under full power, i dont know that you need a whole ton of surge can... but i cannot say for sure.

say i had a 1.5L can... put the pump in there... what is it now? and is it enough? and the setup would cap off at 650-700rwhp TOPS...unless you added another inline pump but 3 pumps doing different jobs is pretty overcomplicated, better off to just go external surge can at that point.

ttg35fort

iTrader: (2)

Right now with two Walbros running the sound is quite irritating. I imagine with 3 it will be even worse. Also, without an external surge tank, if one of the Walbros picks up air, I would be concerned about that air going through the fuel line and to the injectors.

I think the safe bet is going with the external surge/swirl tank. I am going back to the stock fuel pump hangar with a single Walbro to supply the external surge tank. I'm also going to drill holes in the stock swirl tank to allow significantly more fuel to flow into it. On the down side, some of that fuel will run out through the holes in high G turns.

Nonetheless, my external surge tank holds 1.6 L, which should be more than adequate. Since I am pushing the motor hard for 20 minute stretches while running on the track, I'll be turning my boost down to run no more than about 550 rwhp, which translates to approximately about 265 lph of fuel flow at the most. For safety, I have estimated my driveline losses a little on the high side (18%) and the energy conversion efficiency of the motor on the low side (28%), so my maximum fuel flow will in actuality probably be below 240 lph, and much lower when the meth system is on line because it also will be providing fuel. I do intend to run the meth system while on the track. With my conservative calculation, this gasoline flow will be about 205 lph at most when the meth system is on line, but more likely down around 190 lph, or even lower.

265 lph (worst case scenario) translates to roughly 4.4 L/min. 190 lph trans so roughly 3.2L/min. The 1.6 L surge tank should give me about 22 seconds of additional fuel at WOT in the worst case scenario, and about 30 seconds or more at WOT in the more likely scenario, minus whatever I lose due to slosh in the surge tank. I have yet to hold WOT throttle anywhere more than a few seconds while exiting a turn, and I have baffles in my external surge tank to reduce the slosh problem.

On the straights, slosh will not be a problem with my surge tank design because the 3.5" OD tube is horizontally mounted. At Sebring, the stock swirl tank ran dry toward the end of the long straights, usually within 5-10 seconds of the next turn. So between modifying the stock swirl tank to allow gasoline to flow in much faster, and installing the external surge tank, I am very confident that my fuel delivery issues will be solved. I'll let everyone know it works after I have my motor back together and run my first event.

TrackPack

iTrader: (1)

With out measuring these are rough calculatiuons:

The 044 would displace approximately 400cc of fluid which would make the internal volume of your 1.5liter can more like 1.1 liters, now 1.1 liters of fuel without any refill assist from the other intank pump would provide aprox. 15 seconds of fueling at a constant 700whp. Now the issue is that the lower in volume the the surge canister becomes the more vulnerable to fuel slosh and drawing in air it becomes which is why you generally "over- volume" the design. Now I realize that a constant 700whp isn't the norm...especially in a high G situation so that adds some time to the calculation also you would hope the other intank would be assisting a little in the process.
I would definitely baffle the pickup in the tank in a low volume design such as this. I would feel comfortable saying that a well designed/baffled 1.1liter tank at 700whp would provide a solid 10seconds of hassle free fueling in any high G application. Now that may not sound like alot but keep in mind I over design and I'm very careful with claims,(10 secs if a long f*ckin' time to be WOT at 700whp btw!lol) also consider that through a high G turn you would probably be a half throttle/power and thus have twice if not more fuel available to you equaling 20+ seconds of safety.

At the end of the day it would provide a better alternative than anything we have today available in a drop in application in the community. We would get a reliable bosch out of the deal, 700whp fueling, and a proper(not as big as I like but atleast functional unlike the other only available option lol) surge tank for the track stars, well as proper as can be designed for the space provided anyways.

I think it would be a great option for the community Charles, I would even say it would be the best available option to date, it wouldn't provide the volume of your twin pump but it would be a very reliable option for the higher whp track enthusiast.

chopperman

iTrader: (9)

Waiting on results

JETPILOT

iTrader: (51)

Have you run the full course at Sebring yet? What kind of times are you running on the full course? I have 565 whp now and on the full course it's just too much. It's a handful to drive. I'm going to be making another map for 450whp. I think the car will be faster with less power. Throttle modulation is a real ***** with high power.

phunk

iTrader: (21)

Trackpack, I think I'll try it... It will take a few weeks tho as we are workng on finishing this batch of hr rails and the front intake. It will be pricey since it's not just a sheet metal box but I don't think it will be too bad. I need to borrow a pump from someone

ttg35fort

iTrader: (2)

It was the full course. But I'm still in the learning mode. I was with an instructor and was not monitoring my lap times. I was more focussed on learning the lines, especially turn 5. When I was driving at a moderate pace, I did OK. But when I went at it fast, I kept screwing up my line there. Turn 7 is where I did the 4 wheel power slide. That was fun. When I ran it I had my boost turned down to 12 psi because it was my first time there. Also, Roger pulled back my timing and richened up the fuel mixture before the event, so I was proabably only pulling around 475 rwhp on that day. It was enough to pull away from a 911 that was trying to keep up with me though.

rrmedicx

iTrader: (54)

Phunk (Charles) you had better get back to making some of those intake plenums.
Terry has this plan all worked out. LOL