Road Race Carbureted Ls1 Dry sump

[ctk30]

I am going to mimic your design of modifying the stock windage tray (imitation is the highest form of flattery right?) and add the crank scraper

Now for the the sump design, I searched a little bit on here. It seems like the middle front is a good spot for the pickup, however my rear pickup positioned to on side is less than ideal. I was going to try and come up with some diverters, but maybe I'll just buy another pickup and put it in the middle rear

Then I can cover the whole sump section with either the unidirectional screen, louvered metal like the avaid pan I found, or maybe expanded metal or perforated steel

Blue is the location of the new pickups, green is current. Yellow would be a solid steel perimeter I would make to help calm the initial splash up from shifting oil

[ctk30]

My other idea is to segment the pan into two sections. With something covering the sump area like the other idea

I figure most of the time spent at higher rpm with higher oil flows is gonig to be accelerating forwards, so why not design the pan for this?




Edit: Or something like this and leave the current pickups



http://www.ebay.com/itm/NASCAR-Stefs-St ... Wp&vxp=mtr

[MadBill]

That last pan looks like a six stage piece; your pump is three is it not?

[ctk30]

Yep mines a 3 stage

I didn't clarify, I meant to show it as putting a shelf inside the pan and directing the oil only to one side to the pickups, I could also angle it to let gravity help

That particular pan is a square pan with a hollow shelf, similar to what mine would look like if I did that

[MadBill]

Maybe Kevin or ?? will weigh in here, but if I had only two pick ups, I'd put one in each rear corner. If I could pony up for a third it would go center front.

[Kevin Johnson]

Maybe Kevin or ?? will weigh in here, but if I had only two pick ups, I'd put one in each rear corner. If I could pony up for a third it would go center front.

I am filled with trepidation that he is thinking about putting a hole in the straw. If you add a third pickup you will need to add a fourth stage to your pump assembly. Don't just splice another pickup into an existing tube. if you want to see why, put a hole in a straw near where your lips seal it. It is easier for air to enter than for liquid to be drawn up.

Yep mines a 3 stage

I didn't clarify, I meant to show it as putting a shelf inside the pan and directing the oil only to one side to the pickups, I could also angle it to let gravity help

That particular pan is a square pan with a hollow shelf, similar to what mine would look like if I did that

I was working on a TR4 sump -- similar problem. You might consider creating two transverse baffles to fully segregate the sump well into thirds front to back. in the middle of each baffle make a passage that closely conforms to the pickup body but leaves a 1/4" to 3/8" gap to the floor. In that way, any oil attempting to transfer through will be exposed to the pickup suction.

[ctk30]

I am filled with trepidation that he is thinking about putting a hole in the straw. If you add a third pickup you will need to add a fourth stage to your pump assembly. Don't just splice another pickup into an existing tube. if you want to see why, put a hole in a straw near where your lips seal it. It is easier for air to enter than for liquid to be drawn up.

I was working on a TR4 sump -- similar problem. You might consider creating two transverse baffles to fully segregate the sump well into thirds front to back. in the middle of each baffle make a passage that closely conforms to the pickup body but leaves a 1/4" to 3/8" gap to the floor. In that way, any oil attempting to transfer through will be exposed to the pickup suction.

Only planning on two pickups

I like your idea of dividing it into thirds. How about if I integrate the pickups into the baffle, maybe on one side of the pickup tube. Would probably have 1/3 of the pickup exposed on one side and 2/3 on the other, the 2/3's side being the back of the pan that sees oil under acceleration

I'm not sure this is clear, I'll do a quick "paint cad" sketch on my lunch break

As far as putting something on the baffles to help stop the splashing up, do you think the louvers or screen over the whole sump is necessary? I was thinking of putting a plate on the top of the baffle to form a T shape maybe 1" wide, 1/2" on each side. I can experiment with it

I think I'll do a solid roof like this, maybe a couple dimple died holes

[img]
https://www.circletracksupply.com/image ... 276%29.jpg[/img]

[ctk30]

double post

[Kevin Johnson]

If you have a full length factory tray with interior screening there is no need to repeat the screening over the sump.

[ctk30]

Thats kind of what I figured, I'll add a 1" wide piece along the top of the baffle to add some rigidity and also help the oil not splash directly up

Is this what you had intend when you mentioned the baffles?

[Kevin Johnson]

Thats kind of what I figured, I'll add a 1" wide piece along the top of the baffle to add some rigidity and also help the oil not splash directly up

Is this what you had intend when you mentioned the baffles?

Yes, that should work.

[MadBill]

Doesn't that configuration effectively result in the unworkable 'punctured straw' scenario? Consider when lateral g forces pile the oil up on one side of the divider. At that point the oil will be surging away from the opposite side, leaving one portion of the pickup sucking air...

[ctk30]

That was a worry of mine, but I think enough oil should be flowing through the cutout and underneath the pickup to overcome it

I think the 2/3 or so coverage when accelerating should hopefully be fine also

[Kevin Johnson]

Doesn't that configuration effectively result in the unworkable 'punctured straw' scenario? Consider when lateral g forces pile the oil up on one side of the divider. At that point the oil will be surging away from the opposite side, leaving one portion of the pickup sucking air...

It is normal for a dry sump to suck in a mixture of oil and air at the pickup (or at least one of the pickups). It is critical that the scavenge capacity exceeds the pumping capacity by a comfortable margin which makes this implicit lest the tank be emptied into the interior volume of the engine. Two pickups are marginal in my opinion but some OEMs actually use just one. Cough.

[MadBill]

If rules permit, for that RPM range and head flow, I'd say you need a 1,000+ CFM and a good ultra tall single plane manifold. With a close ratio box, the revs shouldn't drop much below 5500 anywhere you can use full throttle and any benefit of a dual plane will be long gone by then. We used a 1,000 CFM Braswell on our 308" SBF road racer and had no problems at all at the bottom end with a production ratio TKO600. My guess: A big carb/single combo would be worth 40 HP average 5-7,000 and 75 HP peak Vs. a 650/dual.

Definitely finalize such details before getting Mike on the case!

no doubt that would be worth some power but those numbers seem a little optimistic unless the 650 is very, very poorly tuned

Not to beat a dead horse, since a) we've moved on to pan design and b) it turns out the 650 DP is already in hand, but I just came across some tests reported by David Vizard in his How to Build Horsepower book. He tested a 740, a 920 and a 1030 CFM Holley on a 10.5:1 383 SBC with an Air Gap Performer RPM manifold. Peak power was ~508 @ 6300 with the 740, ~527 @ 6700 with the 920 and ~535 @ 6600 with the 1030. A few other observations:

o At 6700, the 1030 was up 58 HP from the 740.

o All three showed identical power at 3500 RPM, but by 4000 the larger two were starting to pull away.

o At the ~4600 RPM torque peak the 1030 was up by ~10 lb-ft. over the other two.

o At 7300, the 1030 was up ~19 HP over the 940.

o I'd like to have seen what a Victor Jr. would have done, but clearly the Edelbrock two-plane would be hard to beat, absent a 7,000+ RPM motor...